MANUFACTURE OF MALEIC ANHYDRIDE

(100 TON PER DAY)

Submitted

In partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGY

IN

CHEMICAL ENGINEERING

By

G. SAI SOUNDARYA

ROLL NO.1008-11-802-032

Under the esteemed guidance of

Prof. Dr V. RAMESH KUMAR

Department of Chemical Engineering

University College of Technology

Osmania University, HYD – 500007 (T.S)

University College of TechnologyOsmania University

CERTIFICATE

This is to certify that thesis entitled “Manufacture Of Maleic Anhydride” being

submitted by Ms.G.Sai Soundarya bearing the Roll No: 1008-11-802-032 , for the

award of the degree of Bachelor of Technology in Chemical Engineering at University

College of Technology, Osmania University, is a record of bonafide work carried out by

her independently during the academic year 2014-15.

Signature of guide

Signature of Head of the Department Signature of principal

Date of viva-voce examination

Signature of internal examiner Signature of external examiner

DECLARATION

I hereby declare that this is the bonafied record of project work ,

entitled “MANUFACTURE OF MALEIC ANHYDRIDE” done under the

supervision of Prof. V. Ramesh Kumar, as a part of partial fulfillment of the

requirements for the award of B. Tech. degree in Chemical Engineering at

College of Technology, Osmania University, Hyderabad.

To the best of my knowledge, the matter embodied in the report has

not been submitted to any other University/Institute for the award of any

Degree/Diploma.

Date:

G.SAI SOUNDARYA

1008-11-802-032

ACKNOWLEDGEMENT

I am very much indebted to Dr V.Ramesh Kumar, professor of

chemical engineering, College of Technology, Osmania University, Hyderabad

for his invaluable suggestions, constructive advice, and guidance throughout

the project work. He was very supportive throughout the project and was

always ready to help.

I am also thankful to all the staff members of College of

Technology, for their cooperation and coordination during the period of my

study and project work.

Special thanks are due to all the members of my family for their

role in successful completion of my study.

G.Sai Soundarya

ContentsABSTRACT.......................................................................................................1

1.Introduction:...................................................................................................2

2.Processes For Manufacture:........................................................................14

3.Process Description:.....................................................................................23

4.Material Balances:.......................................................................................25

5.Energy Balance.............................................................................................32

6.Process Equipment Design..........................................................................40

7.Instrumentation & Process Control...........................................................89

8.Materials of Construction............................................................................96

9. Plant Layout..............................................................................................100

10. Economic Analysis..................................................................................106

11.Safety And Health Hazards & pollution Control..................................109

12. References:...............................................................................................117

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ABSTRACT

The increasing demand of current world production for Maleic Anhydride

emphasizes the need to focus on the techno-economic analysis of the existing technologies.

Manufacturing of anhydride from Butane are chosen for technical analysis followed by cost

estimation and economic assessment.

The technical part involves the development of flow sheets, process design, carrying

out of calculations as well as estimation of raw materials, labor, utilities, and process

equipment by sizing and other sub-components. The economic part comprises the

estimation of working capital, fixed capital investment, total capital investment, and total

production costs. The results obtained from technical analysis and economical feasibility

studies show that the this process based technology has clear advantages in terms of raw

material consumption and economic competitiveness.

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1. Introduction:

Maleic Anhydride is a multifunctional cyclic organic chemical compound and as

the name suggests , anhydride of maleic acid. It is a major intermediate product

manufactured and consumed in large scale all over the world and has vast importance in

nearly every field of industrial chemistry.

It is an important raw material that is being extensively used in the manufacture

of pthalic type alkyd and unsaturated polyester resins, surface coatings, lubricant additives,

plasticizers and stabilizers, copolymers, food additives, preservative for oils and fats,

paper, vulcanising and modifying agents, for, rubber, synthetic polymers, permanent press

resins used in textiles and agricultural chemicals such as pesticides.

Chemical formula: C2H2(CO)2O

Structure of Maleic Anhydride:

Maleic anhydride is a 5-membered ring compound. The anhydride is a stable

compound containing two acid carbonyl groups and a double bond in α and β positions.

Nomenclature of the compound :

Maleic anhydride is a common name given to the compound based on naturally

occuring malic acid.The compound has other names based on nomenclature .the compound

is also called 2,5-Furandione , dihydro-2,5-dioxofuran,toxilic anhydride or cis-butenedioic

anhydride.

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History Of Maleic Anhydride:

Maleic Anhydride was initially amalgamated in 1830s but was not industrially

manufactured till 1933.The National Aniline And Chemical Co..,Inc ., in 1933

manufactured maleic anhydride industrially for commercial purposes, by oxidising benzene

using a vanadium oxide catalyst.

Properties Of Maleic Anhydride:

Physical Properties:

Property Maleic Anhydride

Formula C4H2O3

Molecular Weight 98.06

Physical State Solid

Colour White to colourless

Odour Chocking,irritating

Boiling point οC 202

Melting Point οC 52.85

Specific Gravity @60οC 1.31

Specific Gravity ,solid 1.43

Specific Gravity,Vapour/Air 13.38

Flash Point,οC 110

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Autoignition TemperatureοC 447

Heat Of Combustion,Kcal/mole 333.9

HeatOfFormation,solid,Kcal/mole 112.2

Heat Of Fusion,Kcal/mole 3.26

Heat Of Hydration,Kcal/mole 8.33

Heat Of Vapourisation,Kcal/mole 13.1

Dipole Moment 10-30C.m 13.2

Appearance Free flowing white solid and exists in the form of, needles,

crystals, flakes or pellets

Crystalline Form Orthorhombic

Heat Of Neutralisation KJ/mole4 126.9

Heat Capacity,KJ/(K Mol)4

Solid

Liquid

0.1199

0.164

Solubiity Data Of Maleic Anhydride:

Maleic Anhydride is soluble in organic solvents such as acetone,bezene,toulene,kerosene ,etc..,

Solvent at 25οC Maleic Anhydride

Acetone 227

Benzene 50

Toulene 23.4

o-Xylene 19.4

Kerosene .25

Chloroform 52.5

Carbon Tetrachloride 0.6

Ethyl Acetate 112

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Maleic Anhydride is a nearly planar molecule with the ring oxygen atom lying 0.003nm

out of molecular plane accorind to the data from single crystal X-Ray diffraction data . A twofold

rotation axis bisects the doublebond and passes through the ring oxygen atom.

Chemical Properties:

The broad industrial applications for this compound is due to its reactivity of the

double bond in conjugation with the two carbonyl oxygens.

Alkylation:

Maleic Anhydride reacts with alkenes activated by α-β unsaturation or an

adjacentaromatic resonance to produce succinic anhydride derivatives .the reaction

conditions are 150 to 300 C and upto 2Mpa pressure.

polyAlkenyl succinic anhydrides are prepared under these conditions by the reaction of

polyalkenes in a nonaqueous dispersion of maleic anhydride ,mineral oil and surfactant.

N-Alkylpyrroles react with maleic anhydride to give electrophilic substitution.

Acid Halide Formation:

Maleic Anhydride when treated with various reagents such as

phosgene,phthaloyl chloride or bromide ,phosphorus pentachloride ,or thionyl chloride or

thioyl halide gives 5,5-dichloro-2furanone .Maleic anhydride reacts with carbon tetra

chloride or tetra bromide at 220οC over activated carbon to form Noncyclic maleyl chloride

or bromide(6).

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Amidation :

Reaction of maleic anhydride with ammonia,primary and secondary amines

produce mono and di-amides and the reaction is known as amidation.

Maleic anhydride reacts with ammonia to form maleamic acid.

It reacts with primary amines to form amic acids that can be dehydrated to

imides ,polyimides,or isoimides depending on the reaction conditions.Amines and pyridines

decompose maleic anhydride often in a violent reaction and carbon-di-oxide is usually a

biproduct.

Miscellaneous Reactions:

1.

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2.

3. Maleic anhydride dimerizes in a photochemical reaction to form cyclobutane tetracarboxylic

dianhydride (CBTA).

4.

5.

6. Diels –Alder reaction:

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7.

Uses and World Wide consumption:

Maleic anhydride has two types of chemical functionality making it uniquely

useful in chemical synthesis and applications.The derivatives of maleic anhydride has

worldwide consumers and each structure has its own commercial interest.The majority of

maleic anhydride produced is used in unsaturated polyester resin . The other fields in which

maleic anhydride is employed is in prodction of plasticisers and stabilizers , additives and

agricultural chemicals.

1. Unsaturated polyester resins are the most commonly used thermoset resins in the

world. More than 2 million tonnes of unsaturated polyester resins are utilised

globally for the manufacture of a wide assortment of products, including sanitary-

ware, pipes, tanks, gratings and high performance components for the marine and

automotive industry. They are formulated from aromatic dibasic acid such as

phthalic anhydride, an unsaturated dibasic acid such as maleic anhydride and glycol

such as propylene glycol. The polyester chains are then cross linked through the

double bond with vinyl cross linking agents such as styrene . Reinforcement in the

form of glass fibers or other reinforcement fibers maybe added to provide the

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strength requirement of the end product .The exact unsaturated polyester formulation

,its cross linking agent and reinforcement fiber are selected to optimize the

performance of the end product.

Their versatility in use allows unsaturated polyester resins to be used in a

myriad of composite applications. Composite parts can be made at temperatures as

low as 15°C to as high as 150°C depending on the processing requirement of the

application .Unsaturated polyester resins also have excellent service temperatures.

They have good freeze-thaw resistance and can be designed for use in many low to

moderate temperature applications ranging from refrigerated enclosures to hot water

geysers.

When it comes to weight for cost comparisons, unsaturated polyester

resins are much favoured over their metallic counterparts. With the current fuel and

processing costs, the increasing prices of steel and aluminium are pushing more

fabricators to use unsaturated polyester resin composites instead. Another major

advantage is the increased productivity potential. While metals involve the use of

specific smelters, expensive tooling and processing requirements, unsaturated

polyester resins are far cheaper and afford the use of low cost tooling. An

unsaturated polyester resin can be moulded at ambient temperature whereas metals

need to be heated to well over 2000°C before they are melted and poured into mould

cavities. Although the perception is that metals are generally structurally superior,

there has been much advancement in the development of technologies for producing

higher strength composites made from unsaturated polyesters resins.

Collectively there is an ever increasing potential for unsaturated polyester

resins. Their low cost, ease of use and weight advantages make them prime

candidates for a wide variety of structural and decorative applications.

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2. Fumaric acid , succinic acid and malic acid are produced from maleic anhydride.

The primary use of fumaric acid is in manufacture of paper sizing products and is

also used as food acidulant. Malic acid is particularly desirable acidulant in certain

beverage selections , specifically those sweetened with artificial sweetener

aspartame. lube oil additives represent another important market segment for maleic

anhydride derivatives ,the molecular structure of importance being adducts of

polyalkenyl succinic anhydrides.

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3. Maleic anhydride is used in a multitude of applications in which a vinyl copolymer

is produced by the copolymerisation of maleic anhydride with other molecules

having a vinyl functionality.Typical copolymers are styrene maleic ,di-isobutylene

maleic ,acrylic acid maleic,butadiene maleic and C18 alpha olefin-maleic

(emulsification agent and paper coating).

4. Agricultural chemicals such as maleic hydrazide ,endothal, captan, have a wide

range of consumers.they are used for plant growth regulation,fungicides,isecticides,

and herbicides.

5. There are many bio degradable polymers produced from maleic anhydride such as

poly aspartic acid , which is employed in water treatment,detergent builders

etc..,.sulfosuccinic acid esters serve as surface active agents .Alkyd resins are used

as surface coatings.Chlorendricanhydride is used as a flame resistant

compoent.Tetraydropthalic acid and hexahydropthalic anhydride have resin

applications.poly malic anhydride is used as a scale preventer and corrosion inhibitor

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.Maleic anhydride forms polymer with mono-O-methyl –oligoethylene glycol vinyl

ethers ,that are esterified for biomedical and farmaceutical uses.

6.Kvamer process technology licenses a process for production of 1,4-butanediol from

maleic anhydride .This technology can be used to produce a product mix of three

molecules as needed by the producer.

World Maleic Anhydride Capacity By Region

Data in: kilotonnes per annum

Region 2002 2012

North America 235 311

South & Central America 44 41

Western Europe 168 456

Central & Eastern Europe 64 58

Asia 315 483

Africa 10 10

Total 836 1359

Source: Kirk & Othme

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The market for the maleic anhydride was around 3841.1 kilo tons per

annum in 2011 . A steady growth in both the revenue and demand for the maleic

anhydride has been observed in the following years . The graph below predicts the

growth in demand and profit of maleic anhydride in world market based on the

consensus observed and analysed.

Major Producers of Maleic Anhydride in the world (Source: Kirk & Othmer)

Company Location

Bartek Ingredients Inc. Canada

Sasol-Huntsman Germany

DSM NV The Netherlands

Flint Hills Resources LP USA

Huntsman Corporation USA

Huntsman Performance Products USA

Lanxess Corporation USA

Lonza Group AG Switzerland

Marathon Petroleum Company LLC USA

Mitsubishi Chemical Corporation Japan

Mitsui Chemicals, Inc Japan

Mitsui Chemicals Polyurethanes, Inc. Japan

Nippon Shokubai Co., Ltd Japan

NOF Corporation Japan

Polynt SpA Italy

Suzhou Synthetic Chemical Co, Ltd. China

Thirumalai Chemicals Ltd. India

TCL Industries Malaysia Sdn. Bhd. Malaysia

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2.Processes For Manufacture:

Maleic Anhydride is manufactured initially in 1930 by vapour phase

oxidation of benzene and the use of benzene as the feed for manufacture of benzene

continued till early 1980s. several processes have been employed in converting the benzene

to maleic anhydride .

Later after extensive researc into the properties of anhydride and its derivaties

various processes have been designed to obtain the anhydride of high purity at low cost.

Although, not much of economic importance these days, oxidation of butene/isobutylene, to

MA, was looked at, with interest, in 70's. A fewplants were also in operation.

Various manufacturing processes involved in the manufacture of Maleic Anhydride are

1.Manufacture of anhydride from benzene

2.Manufacturing of anhydride from Butane

3. By dehydration of Maleic Acid(very rarely employed in direct manufacture)

4.As a byprodct in the manufacture of Pthalic Anhydride.

In the manufacture of maleic anhydride from hydrocarbons like benzene and butane

various technologies such as catalyst technology, fixed bed process and fluidized bed

process technology are employed based on the requirement of the quality of product and the

economics .

1.Manufacture of maleic Anhydride using Benzene:

The primary reaction is one in which benzene is partially oxidized

to form maleic anhydride (Equation 1). There are three undesired side reactions, the

subsequent combustion of maleic anhydride (Equation 2), the complete combustion of

benzene (Equation 3), and the formation of the by-product, quinone (Equation 4).

C6H6(g)+4.5O2(g) C4H2O3(g)+2CO2+2H20 (1)

C6H6(g)+7.5O2(g) 6C02(g)+3H20(g) (2)

C4H203(g)+3O2(g) 4C02(g)+H20(g) (3)

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C6H6(G)+1.5O2(g) 6H402(g)+H20(g) (4)

(a)Catalyst Based Technology:

The catalyst for the conversion of benzene to maleic anhydride consists of

supported vanadium pentoxide .the support is sually an inert oxide such as

kieselguhr, alumina,or silica and is of low surface area as high surface area adversly

effects the conversion o benzene.The Vanadium Oxide on the surface of the support

is often modified with molybdenum oxide such the catalyst has 70% vanadium

oxide.The molybdenumOxide is said to form either a solid solution or compound

oxide with the vanadium oxide and thus increase the activity of the catalyst.

(b)Fixed Bed Process Technology:

The reactions in the fixed bed reactor are as mentioned above .The benzene

concenntrations used are about 1.5mol% or just below the lower flammable limit of

benzene in air.The reactor operates at conversions greater than 95% and molar yields

greater than 70%.The benzene oxidation reaction runs a little cooler than having

typical reactor temperatures of 350 to 400οC range.The reactor gas is cooled by one

or more heat exchanger and sent to the collection and refining section of the

plant.unreacted benzene and by-products are incinerated.

2.Manufacture Of Anhydride Using Benzene:

The manufature of maleic anhydride by butane as feed stock is similar to

benzene process except the processing conditions and catalyst.Butane is oxidised

using the oxygen in the air .The following reactions occur in the reactor during the

production of maleic anhydride. The oxidation of butane is an exothermic reaction &

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from the reactions mentioned , carbon –di-oxide and cabon-mono-oxide are the

major byproducts obtained during the conversion.

C4H10(g)+3.5O2(g) C4H2O3(g)+4H20 (1)

C4H10(g)+5.5O2(g) 2C02(g)+5H20(g)+2CO (2)

C4H10(g)+3.5O2(g) C02(g)+3H20(g)+C3H4O2 (3)

C4H10(G)+6O2(g) CH202(g)+4H20(g)+3CO2 (4)

(a)Catalyst Based Technology:

The catalyst used in the manufacture of maleic anhydride is vanadium

phosphorus oxide.During the conversion of butane to maleic anhydride there is a

complexity in the reaction.The eight hydrogen atoms must be extracted from butane

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and three oxygen atoms has to be inserted and a ring closure has to occur.The 14

elctrn oxidations occurs extensively on the surface of catalyst. Hence ,eventhough

many catalyst based manufacturing processes are employed the catalyst used is

VPO in all processes.

(b)Fixed Bed Process Technology:

Air is compressed to modest pressures, typically 100 to 200 kPa with either a

centrifugal or axial compressor, and mixed with superheated vaporized butane. Static mixers

are normally employed to ensure good mixing. Butane concentrations are often limited to

less than 1.7 mol % to stay below the lower flammable limit of butane . Operation of the

reactor at butane concentrations below the flammable limit does not eliminate the

requirement for combustion venting, and consequently most processes use rupture disks on

both the inlet and exit reactor heads. The highly exothermic nature of the butane-to-maleic

anhydride reaction and the principal by-product reactions require substantial heat removal

from the reactor. Thus the reaction is carried out in what is effectively a large multitubular

heat exchanger which circulates a mixture of 53% potassium nitrate, KNO3; 40% sodium

nitrite , NaNO2; and 7% sodium nitrate , NaNO3.

Reactor temperatures are in the range of 390 to 430οC. Despite the rapid

circulation of salt on the shell side of the reactor, catalyst temperatures can be 40 to 60οC

higher than the salt temperature. The butane to maleic anhydride reaction typically reaches

its maximum efficiency (maximum yield) at about 85% butane conversion. Reported molar

yields are typically 50 to 60%. Efficient utilization of waste heat from a maleic anhydride

plant is critical to the economic viability of the plant. Often site selection is dictated by the

presence of an economic use for by-product steam. The steam can also be used to drive an

air compressor, generate electricity, or both. Alternatively, an energy consuming process,

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such as a butanediol plant, can be closely coupled with the maleic anhydride plant. Several

such plants have been announced . Design and integration of the heat recovery systems for a

maleic anhydride plant are very site specific. Heat is removed from the reaction gas through

primary and sometimes secondary heat exchangers. In addition to the heat recovered from

the reactor and process gasheat exchangers, additional heat can be recovered from the

destruction of unreacted butane, the carbon monoxide by-product, and other by-products

which cannot be vented directly to the atmosphere. This destruction is done typically in a

specially designed thermal oxidizer or a modified boiler. Reactor operation at 80 to 85%

butane conversion to produce maximum yields provides an opportunity for recycle

processes to recover the unreacted butane in the stream that is sent to the oxidation reactor.

Patents have been issued on recycle processes both with and without added oxygen.

Pantochim has announced the commercialization of a partial recycle process . Mitsubishi

Chemical Corporation has announced plans to add butane recovery from the offgas of their

fluid bed process through the use of BOC Gases’ proprietary selective hydrocarbon

separation system (PETROX) . This technology is particularly well suited to use in fluid bed

processes where the hydrocarbon to air ratio is relatively high and in world areas where

butane has a high value relative to its energy content. Operation of the butane to maleic

anhydride process in a total recycle configuration can produce molar yields that approach

the reaction selectivity which is typically 65 to 75%, significantly higher than the 50 to 60%

molar yields from a single pass, high conversion process. The Du Pont transport bed process

achieves its high reported yields at least partially through implementation of recycle

technology. Recovery of the fuel value of the

butane in the offgas from a single pass configuration plant reduces the economic

attractiveness of recycle operation.

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(C) Fluidized-Bed Process Technology:

Fluidized-bed processes offer the advantage of excellent control of hot spots by rapid

catalyst mixing, simplification of safety issues when operating above the flammable limit,

and a simplified reactor heat-transfer system. Some disadvantages include the effect of back

mixing on the kinetics in the reactor, product destruction and by-product reactions in the

space above the fluidized bed, and vulnerability to large-scale catalyst releases from

explosion venting. Compressed air and butane are typically introduced separately into the

bottom of the fluidized-bed reactor. Heat from the exothermic reaction is removed from the

fluidized bed through steam coils in direct contact with the bed of fluidized solids.

Fluidized-bed reactors exploit the extremely high heat-transfer coefficient between the bed

of fluidized solids and the steam coils. This high heat-transfer coefficient allows a relatively

small heattransfer area in the fluid-bed process for the removal of the heat of reaction

compared to the fixed-bed process. Gas flow patterns in a commercial scale fluid-bed

reactor are generally backmixed, which can lead

to maleic anhydride destruction.

Fluidized-bed reactors require a significant amount of space above the catalyst

level to allow the solids to separate from the gases. This exposure of the product to high

temperatures at relatively long residence times can lead to side reactions and product

destruction. Fluidized-bed processes are operated at high butane concentrations but at longer

gas residence times than fixed-bed processes. The product stream contains gases and

solids. The solids are removed by using either cyclones, filters, or both in combination.

Cyclones are devices used to separate solids from fluids using vortex flow. The product gas

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stream must be cooled before being sent to the collection and refining system. The ALMA

process uses cyclones as a primary separation technique with filters employed as a final

separation step after the off-gas has been cooled and before it is sent to the collection and

refining system . As in the fixed bed process, the reactor off-gas must be incinerated to

destroy unreacted butane and by-products before being vented to the atmosphere. Fluidized-

bed reaction systems are not normally shut down for changing catalyst. Fresh catalyst is

periodically added to manage catalyst activity and particle size distribution. The ALMA

process includes facilities for adding back both catalyst fines and fresh catalyst to the

reactor.

3.By Dehydration of Maleic Acid:

Maleic anhydride can also be obtained by dehydration of maleic acid that is a

byproduct of petroleum industry. This is a rarely used industrial process but is a process

mostly employed at lab scale.The high process conditions and the reactivity of acid to form

acid derivatives and also the economics involved in the dehydration process are the main

reasons for not employing this process industrially on a large scale. The dehydration occurs

in the presence of phosphorus pentoxide to form the anhydride and water.

4. Byproduct Of Pthalic Anhydride Production:

Maleic anhydride is, also, formed as a by-product, from phthalic anhydride

process. From the, present, six phthalic anhydride plants,with an installed capacity of 55,000

TPA, about 2,000 TPA of MA is recoverable.

C6H4(CH3)2 + 3 O2 → C6H4(CO)2O + 3 H2O

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The reaction proceeds with about 70% selectivity. About 10% of maleic anhydride is also

produced

C6H4(CH3)2 + 7.5 O2 → C4H2O3 +4 H2O + 4 CO2

(II) Recovery and Purification:

All processes for the recovery and refining of maleic anhydride must deal with

the efficient separation of maleic anhydride from the large amount of water produced in the

reaction process. Recovery systems can be separated into two general categories: aqueous-

and nonaqueous-based absorption systems. Solvent-based systems have a higher recovery of

maleic anhydride and are more energy efficient than water-based systems.

The Huntsman solvent-based collection and refining system will be used as a

generic model for solventbased recovery systems .The reactor exit gas is cooled in two heat

exchangers for energy recovery. The cooled gas product stream is passed to a solvent

absorber where a proprietary solvent is used to absorb, almost completely, the maleic

anhydride contained in the product stream. The solvent stream, coming from the bottom of

the absorber with a high concentration of maleic anhydride, known as rich oil, is sent to a

stripper where the rich oil is heated and maleic anhydride is vacuum stripped from the

solvent. The vacuum-stripped maleic anhydride is typically greater than 99.8% purity, and is

sent to the purification section of the plant where it is batch distilled to produce extremely

pure maleic anhydride. A small slip stream of the solvent which has had the maleic

anhydride removed by stripping is sent to the solvent purification section of the plant where

impurities are removed. The Scientific Design water-based collection and refining system is

in broad use throughout the world in butane-based and benzene-based plants . The reactor

off-gas is cooled from reaction temperatures in a gas cooler with generation of steam. The

off-gas is then sent to a tempered water-fed aftercooler where it is cooled below the dew

point of maleic anhydride. The liquid droplets of maleic anhydride are separated from the

off-gas by a separator. The condensed crude is pumped to a crude tank for storage. The

maleic anhydride remaining in the gas stream after partial condensation is removed in a

water scrubber by conversion to maleic acid which accumulates in the acid storage section

at the bottom of the scrubber. The acid solution is converted to crude maleic anhydride in a

dual purpose dehydrator/refiner. Xylene is used as an azeotropic agent for the conversion of

maleic acid to maleic anhydride. Water from the dehydration step is recycled to the

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scrubber. When the conversion of the acid solution to crude maleic anhydride is complete,

condensed crude maleic anhydride is added to the still pot and a batch distillation refining

step is conducted. The UCB collection and refining technology also depends on

partial condensation of maleic anhydride and scrubbing with water to recover the maleic

anhydride present in the reaction off-gas. The UCB process departs significantly from

the Scientific Design process when the maleic acid is dehydrated to maleic anhydride. In the

UCB process the water in the maleic acid solution is evaporated to concentrate the acid

solution. The concentrated acid solution and condensed crude maleic anhydride is converted

to maleic anhydride by a thermal process in a specially designed reactor. The resulting crude

maleic anhydride is then purified by distillation.

(iii)Merits Of Butane Over Benzene for The Manufacture of Anhydride:

Benzene, although easily oxidized to maleic anhydride with high selectivity,

is an inherently inefficient feedstock since two excess carbon atoms are present in the raw

material. The price of benzene and its hazardous properties are other factors that

overshadow the yield obtained in the process and hence butane based production has been

replacing the benzene based technologies .

In 1983, Monsanto started up the world's first butane-to-maleic anhydride

plant, incorporating an energy efficient solvent-based product collection and refining

system. This plant was the world's largest maleic anhydride production facility in 1983 at

59,000t/yr capacity, and through rapid advances in catalyst technology has been

debottlenecked to a current capacity of 105,000t/yr (1999). Advances in catalyst technology,

increased regulatory pressures, and continuing cost advantages of butane over benzene have

led to a rapid conversion of benzene- to butane-based plants. By the mid-1980s in the

United States 100% of maleic anhydride production used butane as the feedstock.

Coincident with the rapid development of the butane-based fixed-bed process, several

companies have developed fluidized-bed processes. Two companies, Badger and Denka,

collaborated on the development of an early fluid-bed reaction system which was developed

through the pilot-plant stage but was never commercialized. Three fluid-bed, butane-based

technologies were commercialized during the latter half of the 1980s by Mitsubishi Kasei,

Sohio (British Petroleum), and Alusuisse. A second fluidized-bed technology for the

oxidation of butane to maleic anhydride, known as transport bed, has been developed by Du

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Pont. A world-scale plant in Spain for the production of THF by the hydrogenation of

maleic acid using this technology began production in 1996 . Europe has largely converted

from benzene-based to butane-based maleic anhydride technology with the construction of

several new butane based facilities by CONDEA-Huntsman, Pantochim and Lonza.

3.Process Description:

Pure butane, Stream 2, and compressed air, Stream 3, are mixed and fed to

R-101, an adiabatic reactor, where butane reacts with oxygen to form maleic anhydride.

The reaction is exothermic, therefore, one could consider either a fluidized bed reactor or a

packed bed reactor with heat removal to stay close to isothermal. The reactor effluent is

cooled and sent to T-101, a packed bed absorber, where it is contacted with water, Stream 7,

to remove the light gases and all of the maleic anhydride reacts to form maleic acid. The

vapor effluent, which consists of non- condensables , Stream 8, must be sent to an after-

burner to remove any carbon monoxide prior to venting to the atmosphere. This is not

shown here. The liquid effluent, Stream 9, is then cooled and flashed at 101 kPa and 120°C

in V-101. The vapor effluent from V-101, Stream 11, is sent to waste treatment. Stream 12,

the liquideffluent, is sent to R-102 where maleic acid is broken down to maleic anhydride

and water. The reactor effluent is then sent to distillation column, T-102, where maleic

anhydride and water are separated. The distillate, Stream 14, is sent to waste treatment.

Stream 15, the bottoms, consists of 99-wt.% maleic anhydride.

The conversion of butane is assumed to be 82.2%. The selectivity for each reaction is as

follows [2]:

(1) maleic anhydride 70.0%

(2) carbon dioxide 1.0%

(3) acrylic acid 1.0%

P a g e | 24

(4) formic acid 1.0%

Data that may provide reaction kinetics can be found in US patent 4,317,778.

FLOW SHEET FOR THE MANUFACTURING PLANT

Equipment Summary:

C-101 Air Compressor

E-101 Heat Exchanger

E-102 Heat Exchanger

E-103 Condenser

E-104 Reboiler

P-101A/B Reflux Pump

R-101 Packed Bed Reactor

R-102 Maleic Acid Reactor

P a g e | 25

T-101 Absorption Tower

T-102 Distillation Column

V-101 Flash Vessel

V-102 Reflux Vessel

4.Material Balances:

4.1- Reactor

Air entering at 25 0C and assume the Humidity is 65% from the Psychometer chart

H= 0.018kg water/kg dry air

=0.03 kgmol water/kgmol dry air.

Basis:

120 ton of maleic anhydride per day.

According to US Patent # 4317778 air is provided in this reaction is

Bu : O2

1 : 8.65 (in mol fraction )

From Encyclopedia

Butane unreacted = 17% of entering

Butane converted to maliec anhydride = 53% of entering

Butane converted to Acrilic acid = 1.1% of entering

Butane converted to formic acid = 1.07% of entering

Butane entering = 116 ton/day

= 1829 Kgmol/day

O2 required = 1829*8.65

= 15820.85 kgmol/day

= 553.6 ton/day

N2 required = 15820.85*0.79/0.21

P a g e | 26

= 59516.7 kgmol/day

= 1822.26 ton/day

Hence ,total dry air = 75337.55 kgmol/day

H2O with air = 75337.55*0.03

= 2260.1kgmol/day

= 44.48 ton/day

So butane coming out = 0.17*1829

= 310.83kgmol/day

= 19.72 ton/day

Butane converted to

maliec anhydride = 0.53*1829

= 969.37 kgmol/day

= 103.88 ton/day

Acrilic acid = 0 .011*1829

= 20.119kgmol/day

= 1.584ton/day

formic acid = 0.0107*1829

= 19.57kgmol/day

= 0.9844ton/day

Total butane in-butane consumed = butane coming out of reactor

1829-(969.37+20.119+19.57+x) = 310.93

x=amount of butane consume in cox = 509.01kgmol/day

From the reactions given by stochiometry

P a g e | 27

O2 Balance:

O2 consumed in reaction (1) = 3.5*969.37

= 3392.79

kgmol/day

O2 consumed in reaction (2) = 5.5*509.01

= 2799.56 kgmol/day

O2 consumed in reaction (3) = 3.5*20.119

= 70.42 kgmol/day

O2 consumed in reaction (4) = 6*19.57

= 117.42

kgmol/day

Total O2 consumed = 6380.19 kgmol/day

O2 leaving un reacted = O2 entering -O2 consumed

= 15820-6380.19

= 9439.81 kg mol/day

= 330.342 ton/day

CO2Balance

CO2 produced in reaction in (2) = 2*509.01

= 1018.02

kgmol/day

CO2 produced in reaction in (3) = 1*20.119

= 20.119

kgmol/day

CO2 produced in reaction in (2) = 3*19.57

= 58.71 kgmol/day

Total CO2 produced = 1096.85kg mol/day

= 52.77 ton/day

CO Balance

P a g e | 28

CO produced in reaction in (2) = 2*509.01

= 1018.02 kgmol/day

Total CO produced = 1018.02kgmol/day

= 31.17 ton/day

H2O Balance:

H2O produced in reaction (1) = 4*969.37

= 3777.48 kgmol/day

H2O produced in reaction (2) = 5*509.01

= 2545.05 kgmol/day

H2O produced in reaction (3) = 3*20.119

= 60.357 kgmol/day

H2O produced in reaction (4) = 4*19.57

= 18.57 kgmol/day

Total water produced = 6567.17 kgmol/day

Water with air = 2260.1 kgmol/day

Total H2O outlet = 8821.29 kgmol/day

= 173.63 ton/day

4.2 Material Balance around absorber:

The solubility of Butane in water is 0.0098 kgmol butane/kgmol water at 60 oc and the

solubility of CO, CO2, N2and O2 is negligible.

Water required for absorption = 310.93/0.0098

=31727.55 kgmol/day

= 625 ton/day

P a g e | 29

4.3 Balance around flash vessel:

Stream entering in flash vessel is given below

H2O=778.788 t/d

C3H4O2=1.548 t/d

CH2O=0.9844 t/d

C4H4O4= 103.88 t/d

C4H10=19.33t/d

Total moles entering =40880.53 kgmol/day

Zj=mol fraction in feed

Xj=mol fraction in liquid in outlet

Yj=mol fraction in vapour in outlet

V/F= vapour to feed ratio

Pj=vapour pressure of component supposed

P=Total pressure

By hit and trail method

At 120 oC and

V/F=0.95

Components

Zj Pj

KPa

PPj

1 1 PP FV

Z X i j j

j j X PP Yi

C4H10 0.0076 2068.5 20.41 0.000391 0.00797

CH2O 0.00047 179.27 1.769 0.000272 0.00048

C3H4O2 0.0005 51.7125 0.51 0.000935 0.000477

C4H4O3 0.024 0.06895 0.00068 0.4738 0.000322

H2O 0.967 193.06 1.91 0.5198 0.9905

P a g e | 30

Total 1.000 0.996 0.999

components Liquid stream

kgmol

L*Xj

vapour stream

kgmol

V*Yj

C4H10 0.799 303.91

CH2O 0.55 19.02

C3H4O2 1.83 18.291

C4H4O4 969 0.37

H2O 1072.34 38494.42

4.4 Balance around maleic acid reactor:

By the ref

At 135 oc maliec acid rapidly decomposes into maliec acid and water according to the

reaction

C4H4O4 C4H2O3+H2O

So, H2O produced =969 kgmol /day

Total H2O =969+1072.34=2041.34 kgmol /day=40.18ton/day

Maliec acid produced =969 kgmol/day=103.841ton/day

Maliec acid reactor:

H2O=21.11 t/d C3H4O2=0.144 t/d CH2O=0.0276 t/d C4H4O4= 122.91 t/d C4H10=0.051t/d

H2O=40.18 t/d C3H4O2=0.144 t/d CH2O=0.0276 t/d C4H2O3= 103.8411 t/d C4H10=0.051t/d

4.5 Balance around distillation column :

P a g e | 31

As Butane, Formic acid and Acrylic acid are so small that they can be neglected.

It is assumed that 98% of water is in distillate and 99% maleic acid in bottom.

Feed stream:

H2O= 2041.35 kgmol/day

C4H2O3=969 kgmol/day

C4H10=0.85kgmol/day

CH2O=0.546 kgmo/day

C3H4O2=1.829kgmol/day

Overall balance :

F=D+W --------------1

D+W=3010.35

Maliec acid balance :

0.02*D+0.98*W=966.32---------2

By solving equation 1&2

D= 2063.93 kgmol/day

W=946.42 kgmol/day

Residue:

Maliec acid = 0.98*946.42=927.48kgmol/day=100ton/day

H2O=0.02*946.42=18.93 kgmol/day

Acrylic acid=0.9148 kgmol/day

Formic acid=0.011 kgmol/day

Distillate:

Maliec acid = 41.32 kgmol/day

H2O= 2025.43kgmol/day

P a g e | 32

Acrylic acid= 0.9145kgmol/day

Formic acid=05377 kgmol/day

Butane=0.8047 kgmol/day

5.Energy Balance

5.1 Energy Balance around Air Compressor:

Inlet flow rate =77597.65 Kmol/day= 0.898 kmol/s

Inlet volumetric flowrate:

Where

n=0.898kmol/s

R=0.0821 m3atm/kmol K

P= 1 atm

T=298 K

On substitution,

V=21.97 m3/s

From fig 3.6 of Coulson & Richardson- vol 6, for this flow rate centrifugal compressor

would be used with efficiency EP=75%.

V = nRT/P

P a g e | 33

Outlet temperature for Air:

where

T1=25 oC =298K

P1=101.325Kpa

P2=300 Kpa

m=(γ-1/γEP )

For Air, γ=1.4

On substitution,

m= 0.38

T2=177.6οC=450.6K

Work required per Kmol:

Where

n=(1/1-m)=1.61

Z1=1 (at 25 oC and 1 atm from Perry Handbook)

R=8.314 kJ/KmolK

On substituting

W=3326.56KJ/Kmol

Power requirement:

On substituting

P=3.983MWatt

5.2 Energy Balance around Butane Compressor:

Inlet flow rate =1829 Kmol/day= 0.021 kmol/s

T2= T1*(P2/P1)m

W=Z1T1R1(n/n-1)[(P2/P1)(n/n-1) -1]

P= (W ×0.898Kmol/s)/EP

P a g e | 34

Inlet volumetric flowrate:

Where

n=0.021kmol/s

R=0.0821 m3atm/kmol K

P= 1 atm

T=298 K

On substitution,

V=0.51m3/s

From fig 3.6 of Coulson & Richardson- vol 6, for this flow rate centrifugal compressor

would be used with efficiency EP=67%.

Outlet temperature for Air:

where

T1=25 oC =298K

P1=101.325Kpa

P2=300 Kpa

m=(γ-1/γEP )

For Butane, γ=1.135

On substitution,

m= 0.177

T2=88.32οC=361.32K

Work required per Kmol:

Where

n=(1/1-m)=1.216

Z1=0.98(from fig 3.8 Coulson & Richardson vol 6)

R=8.314 kJ/KmolK

V = nRT/P

T2= T1*(P2/P1)m

W=Z1T1R1(n/n-1)[(P2/P1)(n/n-1) -1]

P a g e | 35

Here,

Tc=425.1 K,

Pc=37.96 bar

We know,

Tr=Tc/T1=0.701,

Pr=P1/Pc=0.0263

On substituting

W=2906.72KJ/Kmol

Power requirement:

On substituting

P=0.091MWatt

5.3 Energy Balance around Mixing Tee:

For a mixer,

Where

ni = no. of moles of ith component

Cpi = heat capacity of ith component

T1 = reference temperature

P= (W ×.021Kmol/s)/EP

Q=∑niʃCPidT (from T1 to T2)

T=?

Butane

T2=88.32 οC

Air

T2=177.14 οC

P a g e | 36

T2= final temperature

For Air,

T1=25οC

T2 = 177.14oC

For Butane,

T1 = 25o C

T2 = 88.32oC

Qin = QA +QB

On Substituting,

Qin= 3.6* 108 kJ/day

We know,

Qin = Q out

On substituting,

T4= 155oC

Q H f P H f R

W=Q/CP∆T

5.4 Around reactor:-

Inlet feed temperature = T1 =155 oC

Out let product temperature T2= 410 oC

Inlet cooling water temperature=t1= 25 oC

Outlet cooling water temperature=t2= 70 oC

Sensible energy

Is given by eq.

where

ni = no. of moles of ith component

Q1=∑niʃCPidT (from T1 to Tref)

P a g e | 37

Cpi = heat capacity of ith component

T1 = reference temperature=25 oC

where

ni = no. of moles of ith component

Cpi = heat capacity of ith component

T1 = reference temperature=25 oC

Q = Q2 -Q1

On Substituting,

Q= 6.5* 108 kJ/day

Heat of reaction

is given by following equation

Q H f P H f R

=-3.19*109 +7.75 * 10 8

= -2.4*109 kJ/day

Q evolved = Q + Q2

= -1.76*109 kj/day

Where ‘–ve’ sign shows that heat is evolved

Amount of water required:-

W=Q2/CP∆T

where

Cp = 4.184 KJ/kg oC

W= 9.3* 106 KJ / day

5.5 Around heat exchanger (E-101)

Inlet temperature =T1=410oC

Q2=∑niʃCPidT (from T1 to Tref)

P a g e | 38

Out let temperature =T2=90 oC

Q=8.2*108KJ/day

5.6 Around absorber

Feed inlet temperature=T2 =90oC

Water inlet temperature=25 oC

Outlet temperature =T=?

where

T1= ref temperature =25oC

Qin =1.59*108 kJ/day

We know,

QIN=QOUT

On substituting

T=90oC

5.7 Around heat exchanger (E-102)

Inlet temperature =T1=90oC

Out let temperature =T2=120 oC

Q=4.9*107KJ/day=574 kJ/s

5.8 Around heat exchanger (E-103)

Inlet temperature =T1=120oC

Out let temperature =T3=160 oC

Reaction temperature T2=135 oC

Q=∑niʃCPidT (T1 to T2)+∆HR+∑niʃCP dt (T2 to T3)

Q=∑niʃCPidT (from T1 to T2)

QIN=∑niʃCPidT (from T1 to T2)

Q=∑niʃCPidT (from T1 to T2)

P a g e | 39

=1.2*106+3.4*107+2.86*106

=1.7*108KJ/day

Q=2019.35KJ/s

5.9Around distillation column

Condenser

Energy balance equation of condenser is

H1Vn=[Lnhd+Dhd]+Qc

H1=∑Hliyni at Ti

= 0.979*2886.91+0.0199*1878.34

=2864 KJ/Kmol

hd=∑hdixdi

=0.979*2564.78+0.0199*1568.64

= 2542.14 KJ/Kmol

Qc=71392 KJ/hr =19.83 kJ/s

latent heat of water =λ1= 40683KJ/Kmol

m λ1=0.979*221.5*40683

=8822047.5 KJ/hr

=2450.6Kwatt

latent heat of malice anhydride = λ2= 54800KJ/Kmol

m λ2=0.0199*221.5*57800

=241550.2 KJ/hr

=67Kwatt

Qact=Qc+m λ1+m λ2

=2537.43KWatt

Around reboiler

Temperature =185 oC (isothermal)

Vapour required =m=96Kmol/hr

Q=m λ=1452.23KJ/s

P a g e | 40

Since the feed enters and leaves isothermally at 185 oC

So sensible heat is zero

5.10 Condenser after Flash Vessel

Qi=∑niʃCPidT+ m λ

where

T1= inlet temperature =120oC

T2=outlet temperature = 100oC

λ = latent heat of vapourization

Qt = 1.69*109 KJ/day

6.Process Equipment Design6.1 Fixed Bed Catalytic Reactors

Introduction:

Fixed-bed catalytic reactors have been aptly characterized as the workhorses of me

process industries. For economical production of large amounts of product, they are usually

the first choice, particularly for gas-phase reactions. Many catalyzed gaseous reactions are

amenable to long catalyst life (1-10 years); and as the time between catalyst change outs

increases, annualized replacement costs decline dramatically, largely due to savings in

shutdown costs. It is not surprising, therefore, that fixed-bed reactors now dominate the

scene in large-scale chemical-product manufacture.

Types of Fixed Bed Reactor:

Fixed-bed reactors fall into one of two major categories:

Adiabatic or

Non-adiabatic.

P a g e | 41

A number of reactor configurations have evolved to fit the unique requirements of

specific types of reactions and conditions. Some of the more common ones used for gas-

phase reactions are summarized in Table (4.1) and the accompanying illustrations. The table

can be used for initial selection of a given reaction system, particularly by comparing it with

the known systems indicated.

Fixed-Bed Reactor Configurations for Gas-Phase Reactions:

Classification Use Typical Applications

Single adiabatic bed

Moderately exothermic Mild hydrogenation

or

endothermic non-

equilibrium

limited

Radial flow Where low AP is Styrene from

essential ethylbenzene

and useful where

change

in moles is large

Adiabatic beds in series High conversion, SO2 oxidation

with intermediate equilibrium Catalytic reforming

cooling or heating limited reactions Ammonia synthesis

Hydrocracking Styrene

from ethylbenzene

Multi-tabular Highly endothermic or Many hydrogenations

non-adiabatic exothermic reactions Ethylene oxidation to

requiring ethylene oxide,

P a g e | 42

close temperature formaldehyde

control to by methanol oxidation,

ensure high selectivity phthalic anhydride

production

Direct-fired Highly endothermic, Steam reforming

non-adiabatic high temperature

reactions

1. SELECTION OF REACTOR TYPE

After analyzing different configuration of fixed bed reactors we have concluded that

for our system the most suitable reactors is multi tube fixed bed reactor. Because oxidation

of butane is highly exothermic reaction, so cooling will be required otherwise the

temperature of reactor will rise and due to rise in temperature the catalyst activity and

selectivity will be affected and in turn, the formation of by-products will increase which is

direct loss of productions.

As reaction temperature is already high 410 oC if we keep the process adiabatic temperature

of reactor will rise and the structure of the catalyst will be changed and catalyst will be

damaged. For such a situation the best reactor is multi-tube fixed bed reactor .

2. CONSTRUCTION AND OPERATION OF MULTI-TUBE FIXED BED REACTOR

Because of the necessity of removing or adding heat, it may not be possible to use

a single large-diameter tube packed with catalyst. In this event the reactor may be built up

of a number of tubes encased in a single body, as illustrated in Fig. The energy exchange

with the surroundings is obtained by circulating, or perhaps boiling, a fluid in the space

between the tubes. If the heat effect is large, each catalyst tube must be small (tubes as small

as 1.0-in. diameter have been used) in order to prevent excessive temperatures within the

reaction mixture. The problem of deciding how large the tube diameter should be, and thus

how many tubes are necessary, to achieve a given production forms an important problem in

the design of such reactors.

P a g e | 43

A disadvantage of this method of cooling is that the rate of heat transfer to the fluid

surrounding the tubes is about the same all along the tube length, but the major share of the

reaction usually takes place near the entrance. For example, in an exothermic reaction the

rate will be relatively large at the entrance to the reactor tube owing to the high

concentrations of reactants existing there. It will become even higher as the reaction mixture

moves a short distance into the tube, because the heat liberated by the high rate of reaction is

greater than that which can be transferred to the cooling fluid. Hence the temperature of the

reaction mixture will rise, causing an increase in the rate of reaction. This continues as the

mixture moves up the tube, until the disappearance of reactants has a larger effect on the

rate than the increase in temperature. Farther along the tube the rate will decrease. The

smaller amount of heat can now be removed through the wall with the result that the

temperature decreases. This situation leads to a maximum in the curve of temperature versus

reactor-tube length.

EFFECT OF VARIABLES ON MULTI-TUBE FIXED BED

REACTOR

Particle Diameter

The overall heat transfer coefficient declines with decrease in particle size in the

usual practical range. Redial gradients increase markedly with decrease in particle size.

Small size, however, may improve rate or selectivity in some case by making catalyst inner

surface more accessible.

P a g e | 44

Tube Diameter

Reducing tube diameter reduces the radial profile. Heat transfer area per unit volume

is inversely proportion al to the tube diameter and reaction temperature is affected by a

change in this area.

Outside Wall Coefficient

Improvement up to the point where this resistance becomes negligible is worthwhile.

Boiling liquids are advantageous because of the high heat transfer coefficient.

Heat of Reaction and Activation Energy

Accurate values should be used since calculated temp. is sensitive to both of these,

particularly to the value of energy of activation. This roust be determined carefully over the

range of interests, but calculated results should be obtained based on different activation

energies over the probable range of accuracy for the data so that final equipment sizing can

be done with a feel for uncertainties.

Particle Thermal Conductivity

One of the mechanisms of radial heat transfer in a bed, conduction through the solid

packing which must quite logically depend on the thermal conductivity of the bed, can be

reasoned to have some dependence on the thermal conductivity of the solid. But since it

only affects one of the several mechanisms, the proportionally cannot be direct. Differences

in effective conductivity and the wall heat transfer coefficient h between beds of packing

P a g e | 45

having high and low solid conductivity may be in the range of a factor of 2-3. The largest

difference will occur at lower Reynolds numbers. Most catalyst carriers have low

conductivities, but some such as carbides have high conductivities.

Design Procedure for Multi-Tubular Fixed Bed Reactor

To calculate weight of catalyst required

If space time is know then

By the knowledge of bulk density of catalyst and weight of catalyst calculate volume

of reactor

Decide the dimensions of tube; keeping in mind that

Calculate volume of one tube and then number of tubes required

Calculate Shell Dia

Calculate Pressure Drop

Dia of tube/dia of catalyst particle>10

Volume of reactor = weight of catalyst / bulk density of catalyst

space time = Volume of reactor/Volume of flow rate

W/FA0=∫X A3

X A 2

dX A/-rA

No. of tubes = Volume of Reactor / Volume of one tube

NT=[[(Ds-k1 )2 π4

+k2 ]-Pt(Ds-k1)(nk3-k4)]/1.223(Pt)2

∆ PL

= (1−ε

ε¿( G

D ρC )¿]

P a g e | 46

Calculate heat transfer co efficient

i. Shell Side

ii. Tube Side

iii. Calculate overall heat transfer coefficient

Calculate area required for heat transfer

Calculate area available for heat transfer

*Area available should be greater than required area

Design Calculations for Multi-Tubular Fixed Bed Reactor

Volume of Reactor

Volumetric flow rate of feed to reactor = Vo = 19.04 m3/s

Space time = τ = 0.15s Ref [US Patent #4317778]

Volume of reactor =V= τVo =2.86 m3

Type and volume of Catalyst

Vanadium Phosphorus Oxide (VPO) catalyst of 0.48 cm in the form of pellet is used

Bed void fraction =φ = 0.4

From the appendix table 1.1

h0=150 (1+0.011 t b )¿¿

hp d

k=3.50(

d pG

μ)e

−4.6d p

d

P a g e | 47

volume of catalyst = (1-φ )V= 1.72 m3

weight of catalyst

Bulk density of VPO =ρc=2836 Kg/m3 Ref [www.chemistry periodic table .htm.]

Weight of catalyst = Vcρc= 4103.92 Kg

Tube length and diameter

Take length and diameter of tube to prevent deviation from plug flow assumption.

From appendix table 1.2 Dt/Dp > 10 & L/Dp>100

Where

Dt = diameter of tube

Dp = diameter of particle

L=length of tube

Take L=250 cm ,Dt=5cm

Dt/Dp=10.48 & L/Dp=520.83( Satisfactory )

Number of Tubes

Volume of one tube = Vt = /4 Dt2 L

Dt = 0.05m L = 2.5 m

Vt = 0.006 m3

Total number of tubes = Nt=V/Vt

V = reactor volume =2.86 m3

Nt = 584

Tube layout

Tube layout is triangular.

P=1.25Do

Where P= tube pitch

Do=outside tube diameter

Do= 6 cm

P = 7.5

Number of tubes at bundle diameter

P a g e | 48

ND = number of tubes at bundle diameter

Nt= total number of tubes = 584

On Substituting, ND =28

Where P= tube pitch

ND = number of tubes at bundle diameter

Di = shell diameter

On Substituting, Di = 2.1 m

Shell Height

Length of tube = 2.5 m

Leaving 20 % spacing above and below

So height of shell = 2 (0.2 2.5) + 2.5 = 3.5 m

Pressure Drop

Tube Side

= bed void fraction = 0.4

DP = particle diameter = 4.8 mm = 0.48 cm

ρf= feed density = .00269 g/cm3

G = mass velocity = 0.274 g/cm2 Sec

μ = viscosity of feed = 0.00022 g/cm. Sec

gc = 980.67 cm2/sec

L = length = 2.5 m = 250 cm

Putting values in above eq. gives

N D=¿

Di=P [N D+1]

∆ PL

= (1−ε

ε¿( G

D ρC )¿]

P a g e | 49

ΔP = 267.5 gm/cm2

And 1033.074 g/cm2 = 1 atm

So ΔP = 0.25 atm

Shell side pressure drop

Mass flow rate = mw=107 kg/s = 235.4 lb/s

Flow area

Where

Ds=shell inside diameter= 82.656 in

Nt=total number of tubes = 584

Dot=tube outside diameter= 2.375 in

Ac= 2778.65 in2= 1.79 m2

Wetted primeter =π Nt Dot

= 4357.4 in

De= (4*flow area)/wetted primeter

Where De= Equivalent diameter= 2.55 in = 0.21 ft

G= mw/Ac

Where G= mass velocity =19.2 lb/ft2/s

Reynolds Number

De=equivalent diameter=0.21ft

μ=viscosity=0.000403 lb/ft/s

Re=10004.96

From appendix fig.1.1

Friction factor for tube side = f = 0.00025

Ac=π4

¿]

Re=GDe

μ

∆ PS=fGS

2 ln

5.22× 1010 D e φ

P a g e | 50

Where

∆Ps= pressure drop

Gs= shell side mass velocity= 43920 lb/ft2/hr

L= length of tube = 8.2ft n= number of passes=1

De=Equivalent diameter=0.21ft

S= specific gravity=1

Ps=0.00036 psi (Negligible )

Calculations of Heat Transfer Co-efficient:

Shell side

tb = average water temperature; oF

= 117.5 oF

De=Equivalent Diameter, in

De = 2.55 in

Now to calculate V’ = velocity of water in fps

Mass velocity = G = 19.92 lb/ft2/s

Water density =ρW =62.3lb/ft3

Water Velocity=V’=0.031fps

On Substituting,

hο=184.09 Btu/ hr. ft2 oF

Wall

ΦS=¿

h0=150 (1+0.011 t b )¿¿

V=GρW

hw=XDi

K w Dm

P a g e | 51

X=tube wall thickness=0.154 in

Di=tube outside diameter =2.375 in

Dm=tube mean diameter=2.22 in

Kw=Thermal conductivity=25 Btu/ hr. ft2 oF

hw=0.00066 Btu/ hr. ft2 oF

Tube Side

An equation proposed by LEVA to find heat transfer co-efficient

inside the tubes filled with catalyst particles

G = tube side mass velocity=2017 lb/hr. ft2

μ = viscosity of tube side fluid=0.073 lb/hr. ft

k = 0.0265 Btu/hr. ft oF

Dp = diameter of particle = 0.0157 ft

D = diameter of tube = 0.164 ft

On Substituting,

hi = 25.51 Btu/hr. ft2 oF

Inside dirt coefficient

From appendix table 1.3 for air

hid = 500 Btu/hr. ft2 ℉

Outside dirt coefficient

From appendix table 1.3 for water

hid = 333.33 Btu/hr. ft2 ℉

Over all H.T. Coefficient

hp d

k=3.50(

d pG

μ)e

−4.6d p

d

1U d

=1hi

do

d i

+d o

h id

+Xdo

kw dm

+ 1hod

+ 1ho

P a g e | 52

do= tube outside diameter =2.375 in

dm= tube mean diameter

UD=overall heat transfer

By putting the values

UD=16.99 Btu/hr. ft2 ℉

Area required for Heat Transfer

Q = 6.8*106 Btu/hr

LMTD = 389℉

Area required for Heat Transfer

A=1028.88 ft2 = 95.63 m2

Area Available for Heat Transfer

Length of tube = Lt = 2.5 m

Outer Dia of tube = Dot = 0.06 m

Surface area of one tube = πDotLt

= 3.14 × 0.06 ×2.5

= 0.47 m2

Total surface area available = 584 × 0.47

= 274.48 m2

So, sufficient area is available for heat transfer.

A=Q

UD LMTD

P a g e | 53

SPECIFICATION SHEET

Identification

Item

Item No.

No. required

Reactor

R-1

1

Function: Production of malice anhydride via butane

Operation: Continuous

Type: Catalytic

Multi tube, fixed bed

Chemical Reaction:

Catalyst:

Shape: Spherical

Size: 4.8 mm

Tube side: Tubes:

Material handled Feed Product No. 709

P a g e | 54

(kg/hr) (kg/hr) Length 2.438 m

C2H5OH 86326 432.58 O. D 63.5 mm

H2O 45.44 214.35 Pitch 79.37 mm pattern

CH3CHO ----- 412.8 Material of construction = copper

O2 635.28 484.96

N2 2090.82 2090.82

Temp (oC) 550 550

Shell side

ShellFluid handled = cooling water Dia = 2.66 m

Temperature 25oC to 45oC

Material of construction = Carbon steel

Heat transfer area required = 77.67 m2

6.2Design of Absorber

Absorptions

The removal of one or more component from the mixture of gases by using a

suitable solvent is second major operation of Chemical Engineering that based on mass

transfer.

In gas absorption a soluble vapours are more or less absorbed in the solvent from its

mixture with inert gas. The 'purpose of such gas scrubbing operations may be any of the

following;

a) For Separation of component having the economic value.

b) As a stage in the preparation of some compound.

c) For removing of undesired component (pollution).

Types of Absorption

P a g e | 55

1) Physical absorption,

2) Chemical Absorption.

Physical Absorption

In physical absorption mass transfer take place purely by diffusion and physical

absorption is governed by the physical equilibria.

Chemical Absorption

In this type of absorption as soon as a particular component comes in contact with

the absorbing liquid a chemical reaction take place. Then by reducing the concentration of

component in the liquid phase, which enhances the rate of diffusion.

Types of Absorbers

There are two major types of absorbers which are used for absorption purposes:

Packed column

Plate column

Comparison between Packed and Plate Column

1) The packed column provides continuous contact between vapour and liquid phases

while the plate column brings the two phases into contact on stage wise basis.

2) SCALE: For column diameter of less than approximately 3 ft. It is more usual to

employ packed towers because of high fabrication cost of small trays. But if the column is

very large then the liquid distribution is problem and large volume of packing and its

weight is problem.

3) PRESSURE DROP: Pressure drop in packed column is less than the plate column. In

plate column there is additional friction generated as the vapour passes through the liquid

on each tray. If there are large No. of Plates in the tower, this pressure drop may be quite

high and the use of packed column could effect considerable saving.

P a g e | 56

4) LIQUID HOLD UP: Because of the liquid on each plate there may be a Urge quantity

of the liquid in plate column, whereas in a packed tower the liquid flows as a thin film

over the packing.

5) SIZE AND COST: For diameters of less than 3 ft. packed tower require lower

fabrication and material costs than plate tower with regard to height, a packed column is

usually shorter than the equivalent plate column.

From the above consideration packed column is selected as the absorber, because in our

case the diameter of the column is approximately 0.8 meter which is less than 3 ft. As the

solubility is infinity so the liquid will absorb as much gases as it remain in contact with

gases so packed tower provide more contact. It is easy to operate.

PACKING

The packing is the most important component of the system. The packing provides

sufficient area for intimate contact between phases. The efficiency of the packing with

respect to both HTU and flow capacity determines to a significance extent the overall size of

the tower. The economics of the installation is therefore tied up with packing choice.

The packings are divided into those types which are dumped at random into the tower

and these which must be stacked by hand. Dumped packing consists of unit 1/4 to 2 inches

in major dimension and are used roost in the smaller columns.The units in stacked packing

are 2 to about 8 inches in size, they are used only in the larger towers.

The Principal Requirement of a Tower packing are:

1) It must be chemically inert to the fluids in the tower.

2) It must be strong without excessive weight.

3) It must contain adequate passages for both streams without excessive liquid hold up or

pressure drop.

4) It must provide good contact between liquid and gas.

5) It must be reasonable in cost.

P a g e | 57

Thus most packing are made of cheap, inert, fairly light materials such as clay, porcelain, or

graphite. Thin-walled metal rings of steel or aluminum are some limes used.

Common Packings are:

a) Berl Saddle.

b) Intalox Saddle.

c) Rasching rings.

d) Lessing rings.

e) Cross-partition rings.

f) Single spiral ring.

g) Double - Spiral ring.

h) Triple - Spiral ring.

Design Calculations of Packed Absorption Tower

98 % of the n-Butane (entering the tower at 12.948 Kgmol/h), 100 % of the Maleic

Anhydride (entering the tower at 40.388 Kgmol/h), 100 % of the Formic Acid (entering the

tower at 0.826 Kgmol/h), and 100% of the Acrylic Acid (entering the tower at 0.833

Kgmol/h) is to be absorbed. The absorption takes place at 170 kN/m2 and 373K.

Basis: 1 hour of operation

Compositions of Components in Gas Mixture at Entrance

Component Mol. Formula Mol. Wt. Kg/h Kgmol/h Mol%

Acrylic Acid C3H4O2 72 60 0.833 0.024

N-Butane C4H10 58 751 12.948 0.4

Carbon Dioxide CO2 44 2110 47.954 1.42

Carbon Monoxide CO 28 1188 42.428 1.25

Formic Acid HCOOH 46 38 0.826 0.024

Maleic Anhydride C4H2O3 98 3958 40.388 1.200

Nitrogen N2 28 69436 2480.000 73.237

P a g e | 58

Oxygen O2 32 12587 393.344 11.616

Water H2O 18 6616 367.556 10.829

Compositions of Components in Liquid Mixture at Exit

Component Mol. Formula Mol. Wt. Kg/h Kgmol/h Mol%

Acrylic Acid C3H4O2 72 60 0.833 0.04

N-Butane C4H10 58 736 12.689 0.60

Carbon Dioxide CO2 44 0 0.000 0.00

Carbon Monoxide CO 28 0.000 0.00

Formic Acid HCOOH 46 38 0.826 0.04

Maleic Acid C4H2O3 98 3958 40.388 1.91

Nitrogen N2 28 69436 0.000 0.00

Oxygen O2 32 12587 0.000 0.00

Water H2O 18 37120 2062.222 97.41

Compositions of Components in Gas Mixture at Exit

Component Mol. Formula Mol. Wt. Kg/h Kgmol/h Mol%

Acrylic Acid C3H4O2 72 0 0.000 0.00

N-Butane C4H10 58 15 0.260 0.01

Carbon Dioxide CO2 44 2110 47.954 1.62

Carbon Monoxide CO 28 1188 42.428 1.43

Formic Acid HCOOH 46 0 0.000 0.00

Maleic Anhydride C4H2O3 98 0 0.000 0.00

Nitrogen N2 28 69436 2480.000 83.66

Oxygen O2 32 12587 393.344 13.28

P a g e | 59

Water H2O 18 0 0.000 0.00

1) Selection of Solvent

The solubility data of these compounds shows that Formic acid, Acrylic and Maleic

Anhydride acid are very soluble in water. The least soluble component of the four

components, which are to be absorbed, is n-Butane. Therefore, we based the design of our

packed absorption tower on the solubility of n-Butane in water.

2) Selection of Packing

Our system, is corrosive, therefore, ceramic material is needed. The mass transfer

efficiency of Intalox Saddles is more than the Raching Rings and Berl Saddles. We have

selected this packing for the efficient operation. It is expensive than Raching Rings and Berl

Saddles. To avoid environmental pollution and to recycle n-Butane to the reactor we have to

absorb n-Butane as much as possible. Intalox Saddles (2 inch) of ceramic material is the best

choice for our required conditions.

3) Calculation of Column Diameter

Most methods for determining the size of randomly packed towers are derived from

the Sherwood correlation, which is used here to find out the diameter of the absorber. The

physical properties of gas can be taken as that of air at 60 0C and 170kN/m2 because

concentration of n-Butane is very small in gas mixture and average molecular weight of gas

mixture = 29. The flow rate of water to absorb the n- Butane has been optimized in the

context of calculation of height of absorber, which is 31230 Kg/h.

The abscissa of Fig.2.1 =( LG )¿).5

L = Flow rate of water 31230 Kg/h

G = Flow rate of gas 85956 Kg/h

ρV = Density of gas at 60 0C and 170kN/m2

ρL= Density of Water at 60 0C and 170kN/m2

ρV = PM / RT

P = 170kPs = 170kN/m2 = 1.7atm

M = 29 Kg / Kgmol

P a g e | 60

R = 0.082(atmKgmol/m3K)

T = 600C = 333K

ρV = (1.7atm* 29 Kg/Kgmol) / (0.082 atmKgmol/m3K)* 333K

= 2 Kg/m3

ρL= 988Kg/m3 at 60 0C

Therefore abscissa of the Fig.2.1¿( LG )¿).5 =0.02

For 42 mmH2O/m of packing height, from Fig.2.1

K4 = 2

From table 2.1, Fp = 22.3m-1

μL is viscosity of water at 60℃= 0.5 cp \

G* = 7.6 (Kg/m2s)

G = Flow rate of gas 85956 Kg/h

G = Flow rate of gas 23.90 Kg/s

A = Cross-sectional area of the column

A = G / G*

A = 23.90 / 7.6

= 3.14 m2

=2 m

4) Calculation of the Column Height

i. Calculations of Number of Transfer Units

The solubility data of these compounds shows that Formic acid, Acrylic and Maleic

Anhydride acid are very soluble in water. The least soluble component of the four

components, which are to be absorbed, is n-Butane. Therefore, we based the design of our

packed absorption tower on the solubility of n-Butane in water.

Assumptions:

1) Absorption takes place isothermally at 373K

G¿=¿

D = [4∗A /π ¿¿0.5

P a g e | 61

2) Carbon dioxide, Carbon monoxide, Oxygen, and Nitrogen are insoluble in water at this

temperature

3) n-Butane is our key component

Equilibrium Curve

As the concentration of solute is very small, the flow of gas and the liquid will be

essentially constant throughout the column, and the operating line as well as the equilibrium

curve for our system is straight lines. According to solubility data of n-Butane the

equilibrium curve of n-Butane-Water System (Fig.1) is straight line with a slope of 0.47 at

170 kN/m2 and 373K. Hence the equation of equilibrium curve for n-Butane-Water System

at 170 kN/m2 and 373K is:

Y * = 0.47*X----------------- (1)

Optimum Flow Rate

m = 0.47, Gm = 0.262 Kgmol/m2s then from fig.2.2

mGm/Lm 0.7 0.75 0.80 0.85 0.9

NOG 8 9 11 13 16

Opt = 0.75 which gives the optimum water flow rate Lm = 0.153 Kgmol/m2s.

Operating Line

We have to remove n-Butane from an inert gas stream of 2964 Kgmol/h in a packed

column. The inlet gas contains 0.38-mole percent n-Butane and the outlet

P a g e | 62

gas stream can contain 0.02-mole percent n-Butane. A pure inert water stream enters the

packed tower at a rate of 1735 Kg mol/h.

Taking a point in the absorption tower where Mol.fr.of n-Butane is X, Y in the liquid

and gas respectively, then by n-Butane material balance across this point and the top of the

absorption tower we have:

Inert gas flow rate G = 2964 Kgmol/h, Inert liquid flow rate L = 1735 Kg mol/h.

G (Y – Y2) = L (X – X2)

2964(Y – 0.0001) = 1735 (X – 0)

Y = 0.6*X + 0.0001-------------(2)

X = 1.7*(Y-0.0001) ------------- (3)

These two equations represent the operating line of the absorption of n-Butane.Now we

assumed different values of Y and calculated their corresponding values of X and Y * using

(3) and (1) respectively which are tabulated in the following table

Y (Assumed) X (Calculated) Y *

0.004 0.00663 0.003116

0.003513 0.00580125 0.002727

0.003025 0.0049725 0.002337

0.002538 0.00414375 0.001948

0.00205 0.003315 0.001558

0.001563 0.00248625 0.001169

0.001075 0.0016575 0.000779

0.000588 0.00082875 0.00039

1e-04 0 0

The plot of the X VS. Y graph and X VS. Y * is shown in Fig. (2). As we have plotted the

operating line and equilibrium curve on the same graph, therefore the number of transfer

units are stepped off by using McCabe-And-Thiele Method as shown in fig (2).

NOG = 9, which is the same as obtained from the Fig.2

P a g e | 63

Fig 2

CALCULATION OF HOG

For two inch Ceramic Intalox Saddles HG = 0.5, HL = 0.6 (table 2.2)

HOG = Height of transfer units, based on overall gas film, co-efficient in m

HOG = HG + (m Gm/Lm)* HL = 0.95 m

Gm = Molar flow rate of gas in lbmol / h ft 2= 0.262 Kgmol / m2s

Lm = Molar flow rate of liquid in lbmol / h ft 2

= 0.153 Kgmol / m2s

Therefore height of the Packing, Z = HOG * NOG = 0.95*9 = 8.55m

Allowance for the Liquid distribution = 1.2 m

Allowance for the Liquid distribution = 1.2 m

Hence the total height of the Column = 3.73 +1.2 +1.0 = 10.95m

Height of column can be taken as = 11 m

5) Calculation of Pressure Drop (∆P)

In Operating Region

P a g e | 64

This bed should be in two sections; thereby requiring one intermediate combined

packing support and redistribution plate. It requires one bottom support plate only:

Pressure drop due to one redistributor and one bottom plate = 2 in H2O

Total pressure drop = 8.55*3.28*0.5 + 2

= 16.022in H2O = 16.022*0.250 = 4 kN/m2

At Flooding Region

∆P = 3.0 in. of H2O / ft of packing (from table 2.1)

= 3* 8.55 * 3.28 +2= 86.13 in H2O = 86.13*0.250 = 21.53 kN/m2

6) Evaluation of Operating Conditions

Calculation of Operating Velocity

Reading the abscissa of Fig.2.3 at value

The abscissa of Fig.2.3 = = 0.02

The value of ordinate = 0.035

Therefore, operating velocity for the gas from:

G 2 Fμ L 0.1/ ρV( ρL ρV )gc = 0.035,

G = 5 ft/s = 1.52 m/s

Calculation of Flooding Velocity

Reading the abscissa of Fig.2.3 at value

The abscissa of Fig.1=( LG )¿).5 =0.02

Ordinate for flooding line = 0.19 (for dumped packings for the same abscissa)

Therefore, flooding velocity for the gas from:

G 2 Fμ L 0.1/ ρV( ρL ρV )gc = 0.19,

G = 9.25 ft/s = 2.82 m/s

P a g e | 65

Operating velocity as %age of the flooding velocity

= (1.52/2.82)*100 = 54 %.

Calculation of Percent Flooding of Velocity

Reading the abscissa of Fig.2.3 at value

The abscissa of Fig.5

( LG )¿).5 = 0.02

G 2 Fμ L 0.1/ ρV( ρL ρV )gc = 0.035,

Ordinate for flooding line = 0.19 (for dumped packings for the same abscissa)

% Flooding = [0.035/0.19] 100 =18.42%

Pressure drop at flooding region = 21.53 kN/m2

Pressure drop at operating region = 4 kN/m2

Therefore, % flooding of liquid = (4 /21.53)*100 = 18.6 %

Calculation of Liquid Hold up and Support Load

Liquid hold up (htw):

htw = 0.0004(L / dp) 0.6

L = superficial mass flow rate of water, lb/hr.ft2 = 2027 lb/hr.s

dp = Equivalent dia of the packing, ft from table 2.3 = 0.115 ft

Therefore, the liquid hold up is:

htw = 0.14 ft3 of water / ft3 of column volume

Calculation of Number of Streams for Liquid Distribution at the Top of

Packing

Number of liquid distribution streams at the top of the packing

D = Diameter of the absorption column in inches = 59inch

Ns= (D / 6) 2

P a g e | 66

Putting values in above equations, we get, Ns = 100

Caluclation of Wetting Rate (LP)

Lp = Liquid flow rate per unit cross-sectional area / Specific area of packing

= 2.80*10-3 m3/m2s

Sp.area of packing from table 4 = 11 m2/m3,

Lp = 2.76*10-3/11 = 2.5* 10 –4 (m3 / m s)

SPECIFICATION SHEET

Identification

Item: Packed Absorption Column

Item No.T-101

No. required 01

Function: To absorb n-Butane, maleic anhydride, formic acid and acrylic acid in water.

Operation: Continuous

P a g e | 67

Entering gas Exit gas Liquid Liquid leaving

Kg/hr(Kgmol/hr) Kg/hr(Kgmol/hr) entering Kg/hr(Kgmol/hr)

Kg/hr

96744(3386) 82992(2964) 31230(1735) 123935(2117)

Design Data

No. of transfer units = 9

Height of transfer units = 0.95 m

Height of packing section = 8.55 m)

Total height of column = 11m

Inside diameter = 2 m

Flooding velocity = 9.25m/sec

Maximum allowable gas velocity = 5.0 m/sec

Pressure drop = 42 mmH2O/m of packing

Internals

Size and type = 50.8 mm, Intalox saddle

Material of packing: Ceramic

Method of packing: (wet) float into tower filled with water.

Packing arrangement: dumped

Type of packing support: simple grid & perforated support

6.3 Distillation Column

In industry it is common practice to separate a liquid mixture by distillating the

component, which have lover boiling points when they are in pure

condition from those having higher boiling points. This process is accomplished by partial

vaporization and subsequent condensation.

Here in our project “production of Maleic Anhydride from n-butane”

Maliec anhydride is separated from water.

P a g e | 68

The choice between plate and packed column

Vapour liquid mass transfer operation may be carried either in plate column or packed

column. These two types of operations are quite different. A selection scheme considering

the factors under four headings.

i) Factors that depend on the system i.e. Scale, foaming, fouling factors, corrosive systems,

heat evolution, pressure drop, liquid holdup.

ii) Factors that depend on the fluid flow moment.

iii) Factors that depends upon the physical characteristics of the column and its internals i.e.

Maintenance, weight, side stream, size and cost.

iv) Factors that depend upon mode of operation i.e. Batch distillation, continuous

distillation, turndown, intermittent distillation.

The relative merits of plate over packed column are as follows:

i) Plate column are designed to handle wide range of liquid flow rates without flooding.

ii) If a system contains solid contents, it will be handled in plate column, because solid will

accumulate in the voids and coating the packing materials and making it ineffective.

iii) Dispersion difficulties are handled in plate column when flow rate of liquid are low as

compared to gases.

iv) For large column heights, weight of the packed column is more than plate column.

v) If periodic cleaning is required, main holes will be provided for cleaning. In packed

columns packing must be removed before cleaning.

vi) For non-foaming systems the plate column are preferred.

vii) Design information for plate column are more readily available and more reliable that

that for packed column.

viii) Inter stage cooling can be provide to remove heat of reaction or solution.

ix) When temperature change is involved, packing may be damaged.

P a g e | 69

For particular process, “Maliec Anhydride and water system”, we have

selected plate column due to:

i) System is non-foaming.

ii) Temperature change is high (75o c).

iii) The column diameter is greater than 0.6 m

iv) The vapour flow rate is high as compared to liquid flow rate so if packed column is used

due to low liquid flow rate liquid and vapour contact would not be good so efficiency will

decrease.

CHOICE OF PLATE TYPES

There are four main tray types, the bubble cap, sieve tray, ballast or valve trays and the

counter flow trays. I have selected sieve tray because:

i) They are lighter in weight, less expensive. It is easier and cheaper to install.

ii) Pressure drop is low as compared to bubble cap trays.

iii) Peak efficiency is generally high.

iv) Maintenance cost is reduced due to the ease of cleaning.

v) Since sieve trays rely on vapour flow rate, the vapour flow rate is high so no weeping

occurs.

P a g e | 70

DISTILLATION COLUMN DESIGN

Feed Composition & Flow Rates (F)

Component Mass Flow Molar Flow Mol. Fraction

Rate Rate (Kmol/hr)

(Kg/hr)

H2O 1531 85.056 0.677

Maleic Anhydride 3957.24 40.38 0.321

Butane 1..914 0.033 .000267(negligible)

Formic acid .0228 0.0228 0.000182(negligible)

Acrylic acid 5.472 0.076 0.000607(negligible)

5495.6 125.5 1.00

Top Product Composition and Flow Rate(D)

Component Mass Flow Molar Flow Mol. Fraction

Rate Rate(Kmol/hr)

Kg/hr

H2O 1519 84.39 0.979

Maleic Anhydride 168.7 1.722 0.0199

Butane 1.931 0.0333 0.000389(negligible)

P a g e | 71

Formic acid 1.012 0.022 0.00026(negligible)

Acrylic acid 2.736 0.038 0.000442(negligible)

Total 1693.4 86.2 1.00

Bottom Product Composition & Flow Rates (B)

Component Mass Flow Molar Flow Mol. Fraction

Rate Rate(Kmol/hr)

Kg/hr

H2O 14.36 0.789 0.0199

Maleic Anhydride 3786.72 38.64 0.979

Butane 0 0 0

Formic acid 0.0211 0.00046 0.0000116(negligible)

Acrylic acid 2.736 0.038 0.000965(negligible)

Total 3803.83 39.47 1.00

ASSUMPTION

Binary distillation (H2O & maleic anhydride)

Ideal gas behaviour of vapours.

1. BOTTOM TEMPERATURE (TB) Bubble point calculations:-

PT = 1.2atm, T=185 oC (Assume)

Components Xb=Xi V.P(psia) Ki=V.P/PT Yi= KiXi

Maleic anhydride 0.979 11.76 0.8 0.7832

Water 0.0199 1.80 12.24 0.2435

Total 1.00 1.02

2.Top Temperature:-

Dew Point Temperature

PT = 1.2atm

TD =110 oC (Assume)

P a g e | 72

Components Yi=XF V.P(psia) Ki=V.P/PT Xi= Yi/ Ki

Maleic anhydride 0.0199 0.7 0.048 0.41

Water 0.979 23 1.56 0.615

Total 1.00 1.025

3.Temperature of Feed(TF):-

TF =160 oC

4. Feed Conditions:-

Dew point calculations:-

T=160.5℃

Components XF=Yi V.P(psia) Ki=V.P/PT Xi= Yi/Ki

Water 0.677 100 6.8 0.0929

Maleic anhydride 0.322 5.17 0.325 0.91

Total 1.00 1.0029

Since the dew point of feed is same as feed temperature so feed is at its dew point.

5. Calculation for α (Relative Volatility)

TF = Feed Temperature (oC) =160

Light key component (LK) =water

Heavy key component (HK) =malice anhydride

Component Top Bottom Average

Ki DiKi/KHK Ki BiKi/KHK α

Maleic 0.048 1 0.8 1 1

Anhydride

Water 1.56 32 12.24 15 21.7

6.Minimum Number of Plates (Nm)

P a g e | 73

Fensky Equation

S = still, (αAB)av = α = 21.7

Nm = 3

7.Caluclation of Rm(Minimum Reflux Ratio)

As feed is at its dew point so q = 0

By trial θ = 12.3

α A

xfA

α

B x

fB1 q

α A θ α B θ

P a g e | 74

Using eq. of min. reflux ratio

α A

xfA

α B

xfB R 1

α A θ α B θm

A = water, LK B = malice anhydride, HK

D = distillate

XfA=mol fraction of component corresponding to light key in feed.

XfB=mol fraction of component corresponding to heavy key in feed.

Rm = 1.26

8. Reflux Ratio (R)

R=1.25(Rm)

=1.57

9. Actual Number of theorical stages

From “Kirk bride” relation

N=8

10. Column Efficiency

Where

μ1=viscosity of liquid at mean tower temperature

μw=viscosity of water at 293 k

Xf = mol fraction of components in feed

N−Nm

N+1=0.75 [1−( R−Rm

R+1

0.566)]

E=0.17−0.616 log10 ∑[ x f ( μ1

μw)]

P a g e | 75

Mean tower temperature = 147.5 0C= 420.5 K

μ1= 0.174 cp

μw= 0.83 cp

Xf = 0.677

For maleic anhydride

μ1= 0.485 cp

μw= 0.83 cp

xf = 0.321

On Calculating

E = 0.48

11. ACTUAL NUMBER OF PLATES

Taking reboiler as a stage.

where

Na = actual number of plates

N = theoretical plates

E = efficiency

Na = 15

12.Feed Plate Location

Where

Nr = number of stages above the feed, including any partial condenser,

Ns = number of stages below the feed, including the reboiler,

B = molar flow bottom product,

D =molar flow top product,

Na=N−1

E

P a g e | 76

xf,HK = concentration of the heavy key in the feed,

xf,LK =concentration of the light key in the feed,

xd,HK = concentration of the heavy key in the top product,

xb,LK = concentration of the light key if in the bottom product.

B=39.47 Kmol/hr

D=86.2Kmol/hr

ND/NB= 0.9928

Na-NB=0.9928NB

NB=8

ND=7

So feed enters the column at 8th stage.

13. Column Pressure Drop

Assume 170 mm. water pressure drop per plate

∆Pt = 9.81ht *10-3 ρL Na

Where

∆Pt = total pressure drop (pa)

ht =Total plate pressure drop(mm liquid)

ρL = Density of liquid(H2O) at 25 o C

Na =actual no. of plates

By putting Values in above eq.

∆Pt = 25015.5 pa

Top pressure = 121.6*103 pa

Estimated bottom pressure = 146615.5 pa=1.44 atm

14. Liquid Vapour Flow Factor

Where

FLV =( Lm

T m)¿

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Lm=liquid flow rate (kg/sec)

Vm=vapour flow rate (kg/sec)

For top:-

Balance around condenser

Vn = Ln+ D

Vn = 221.5 kmol/hr

=1.21 kg /sec

Ttop=110℃

Av. Mol. Wt.=19.6 kg/k.mol

ρ v= 0.75kg/m3

ρL= 963.95 kg/m3 (From Perry)

So

FLVtop=0.016

For bottom:-

Balance around reboiler

Lm = Vm +B

135.3=Vm+39.47

Vm = 96 Kmol/hr

=0.422Kg/sec

Tbottom = 185o C

Av.mol wt=96.3

ρ v=3.7 Kg/m3

ρL=1302.2 Kg/m3 (table 3.1)

On Substituting,

FLV bottom =0.075

15. FLOODING VELOCITIES:-

U f=K1 √ ρL−¿ ρV

ρV

¿

P a g e | 78

U f= flooding vapour velocity

K1* = constant from fig 3.1

Whereσ =surface tension

By “sudgenparachor” method

where

σ = surface tension

pCh= sudgen’sparachors constant

M = mol.wt

At top:-

From fig 3.1 ,

K1* = 0.095

pCh= 54.2

σ top = 50 mJ/m2 = 5*10 -2 N/m

K1 = 0.114

Uf = 4.08 m/s

At bottom:-

From fig 3.1,

K1* = 0.090

pCh = 216.6

σ bottom = 21.7*10 -3 N/m

K1 = 0.0912

Uf = 2.58 m/s

Designing at 85% flooding at maximum flow rate

Corrected K1 =K1*¿

σ=¿

P a g e | 79

Top UV = 0.85 * Uf = 3.47 m/s

Bottom UV = 0.85 * Uf = 2.2 m/s

16.Maximum Volumetric Flow Rate :-

Top:-

Vn = 221.5 kmol /hr =0.0615 Kmol /sec

Max Volumetric flow rate = Vn ×Μ.wt /ρV

=1.6m3/sec

Bottom:-

Vm = 96 kmol /hr =0.027 Kmol /sec

Max Volumetric flow rate = Vm ×Μ.wt / ρV

=0.72 m3/sec

Net Area Required:-

A top = 0.51m2

A bottom =0.32 m2

Column Cross-Sectional Area :-

Taking down comer area as 12% of total

ACTop = Α T op/0.88

= 0.51 m2

AC Bottom = Abottom/ 0.88

=0.36 m2

19. Column Diameter

A=max . vol flow rateUV

P a g e | 80

DTop = 0.86 m

Dbottom = 0.68m

20. Liquid Flow Pattern

Where

Ln =Liquid Flow rate (k mol/hr)

ρL= Density of Liquid (Kg/m3)

On Substituting,

Ln =135.3 k mol/hr

ρL=963.95 Kg/m3

M=19.6

So max.Volumetric Flow rate = 2.78* 10-3 m3/sec

From fig. 3.2 it is clear that cross flow single Plate is used.

21. Provisional Plate Designing

Sieve plate is selected

Column Dia = Dc = 0.86 m

Column Area = Ac = 0.51 m2

Downcomer Area = Ad = 0.12 Ac = 0.0612m2 (12% of Ac)

Net Area = An = Ac – Ad = 0.448 m2

Active Area = Aa = Ac – 2Ad = 0.387 m2

D=√ 4 AC

π

Max. Volumetric flow Rate=Ln× M . Wt

3600 × ρL

P a g e | 81

Ah = hole area (total) = Aa 0.1 = 0.0387 m2 (10% of Aa)

From fig (3.3)

lw /Dc = 0.76

lw = weir length

lw = 0.654m

Take weir height = hw = 50 mm

Hole diameter = dh = 5mm

Plate thickness = 5 mm

22. Check Weeping :-

Where

LM =Liquid Flow rate below feed plate (k mol/hr)

On Substituting,

LM =135.3 k mol/hr

M. wt =96.3

Max. Liquid flow Rate = 3.62 kg/sec

Max. Liquid flow Rate at 70% turndown = 0.7*3.62 = 2.53 kg/sec

Weir Liquid Crest:-

Where

lw=weir length

how= weir crest, (mm liquid)

Lw= liquid flow rate, kg/sec

Max. Volumetric flow Rate=Ln× M . Wt

3600 × ρL

how=750¿

P a g e | 82

ρL=liquid density at bottom kg/m3

For minimum

On Substituting,

lw=0.654m

Lw= 2.53 ,kg/sec

ρL=1302.2 kg/m3

so ,

how= 15.5, (mm liquid)

For maximum

Substitute,

lw=0.654m

Lw= 3.62, kg/sec

ρL =1302.2 kg/m3

so ,

how= 19.7, (mm liquid)

At minimum rate

hw+how = 65.5 mm liquid

how= 15.5, (mm liquid)

23. Weep Point:

a) Minimum vapour velocity through holes:

ρ v= vap. density at base, kg/m3

dh= hole dia ,mm

U h=[k2−0.90 (25.4−dh)]

¿¿

P a g e | 83

k 2 = const. Fig. 3.4

put

ρ v= 3.7 kg/m3

dh = 5 mm

k 2 = 30.3

so

U h= 6.2 m/s

b) Actual minimum vapour flow velocity:

=0.7×0.702/0.0387

=12.7 m/sec

Since the total minimum vapour rate is above weep point. so no weeping

occurs.

24. Plate Pressure Drop:-

a) Maximum vapour velocity through holes:-

=1.6/0.0387

=41.3 m/sec

b) Pressure Drop Through Dry plate:

Where,

Co = const. from fig 3.5

U a=min. vap flow rate

Ah

hd=51¿

P a g e | 84

At plate thickness/hole dia=5mm/5mm=1 & Ab

Aa

=¿0.1

Co= 0.87

Put

ρV = 0.75 kg/m3

ρL= 963.95 kg/m3

hd=89 mmliq

c) Residual head:

=12.96 mm liq

d)Total pressure drop:-

ht = hd + (hw + how) + hr

Where

hd =pressure drop through dry plate

hw =weir height

how =weir liquid crest (max)

hr =residual head

putting values

ht =171.6 mmliq

This is close to the assumed value of pressure drop, so it is accepted.

25. Down Comer Backup:-

a) Down comer pressure loss:-

Take

hap= hw – 10

Where hw = weir height

hr=125× 103

ρL

P a g e | 85

hap = 40mm

b) Area Under apron:-

Aap = hap lw

Where

hap = height of bottom edge of apron above plate

Lw = weir length

So Aap = 0.026 m2

b) Head loss in downcomer :-

Where

hdc=head loss in down comer (mm)

Lwd= Liquid flow rate in down comer

Am = either the down comer or Area for Clearance Area under down comer Aap

whichever is small

Put

Lwd= 3.62 kg/s

ρL= 963.95 kg/m3

Am = 0.0612m

So

hdc= 0.625 mm

c) Backup in downcomer;-

hbc = hdc + (hw + how max) + h t

Put

hw = 50mm

hdc =0.625 mm

hdc=166¿

P a g e | 86

how max =19.7 mm

ht =190.6 mm

so,

hbc =261 mm = 0.261 m

0.261 < ½ ( plate spacing + weir height)

0.261 < 0.275

so our plate spacing 0.5 m is acceptable

26. Down Comer Residence Time;-

Where

t r= down comer residence time sec

hbc= dead liquid backup m

Lwd= liquid flow rate in Down -comer

ρL= liquid density

hbc = 0.261 m

Lwd= 3.62 kg/s

ρL= 963.95 kg/m3

So

t r= 4.25 sec (>3 (satisfactory))

27. CHECK ENTRAINMENT;-

Where

Un = actual velocity based upon net area

t r=[Ad hbc ρL

Lwd

]

% flooding=[U n

U f

¿

P a g e | 87

Uf = flooding Velocity

put values

Max.volumetric Flow rate =1.6

An = 0.51

Un= 3.14 m/s

Since Uf = 4.08 m/s

% flooding = 77%

from Fig. 3.6 at Flv = 0.016

percent entrainment i.e. = 0.097

28. Number of Holes

Dia of hole ( D) = 50 mm = 0.05 m

Area of Single whole ( A1 ) = π /4D2 = 1.96 * 10 -5 m 2

Total no. of Holes = Ah / A1 = 1975

29. Height of Distillation Column

No. of Plates = 15

Tray Spacing = 0.5 m

Distance between 15 plates = 15 * 0.5 = 7.5 m

Take

top Clearance = 0.5 m

Bottom Clearance = 0.5 m

Plate Thickness = 5mm / plate = 5*10 -3 m / plate

Total thickness of plates = 5* 10 -3 * 15

Un= max.Volumetric flow rate/net area required

P a g e | 88

= 0.075 m

= 75 mm

Total column height = 7.5 m + 0.5 +0.5 m +0.075m = 8.6 m

30. Mechanical Design

Shell material = carbon steel

Sieve plate material = stainless steel 316

Operating pressure =1.2 atm

Taking design pressure 40% more than operating pressure then

Design pressure = 1.68 atm

= 0.168 MPa

shell diameter =0.86 m

shell Height = 8.6 m

Shell thickness =

Where

P= design pressure =0.168 MPa

j= joint efficiency = 0.85

C = corrosion allowance for carbon steel = 2mm = 2*10-3 m/yr

f = allowable stress = 96.26 MPa

Di = internal diameter

ts = 0.046 m = 46 mm

SPECIFICATION SHEET

Identification:

Item Distillation column

Item No. T-102

No. required 1

Tray type Sieve tray

t s=( P2 fj−P )× Di+C

P a g e | 89

Function: separation of maleic anhydride from water

Operation: Continuous

Material handled

Feed Top Bottom

Quantity 125.5 Kgmol/hr 86.2 Kgmol/hr 39.47 Kgmol/hr

5495.6 Kg/hr 1693.4 Kg/hr 3803.83Kg/hr

Composition of 32.2 % 2% 98 %

Maleic Anhydride

Temperature 160 oC 110 o C 185 oC

Design Data

No. of trays = 15 Pressure = 1.2 atm Height of column = 8.6 m

Diameter of column = 0.86 m

hole area/active area = 0.10

weir length = 0.654 m

weir height = 50 mm

reflux ratio = 1.57:1

Hole size = 5 mm

Tray thickness = 5 mm

Flooding = 77 %

tray spacing = 0.5 m No. of holes = 1975

P a g e | 90

7.Instrumentation & Process Control7.1 Instruments

Instruments are provide to monitor the key process variables during plant

operation. They may be incorporated in automatic control loops or used for the manual

monitoring of the process operation. They may also be part of an automatic computer data

logging system. Instruments monitoring critical process variables will be fitted with

automatic alarms to alert the operators to critical and hazardous situations.

It is desirable that the process variable to be monitored be measured directly;

often, however, this is impractical and some dependent variable that is easier to measure, is

monitored in its place. For example, in the control of distillation columns the continuous on-

line, analysis of the over-head product is desirable but difficult and expensive to achieve

reliably, so temperature is often monitored as an indication of composition. The temperature

instrument may form part of a control loop controlling, say, reflux flow; with the

composition of the overheads checked frequently by sampling and laboratory analysis.

7.2 Instrumentation And Control Objectives

The primary objective of the designer when specifying instrumentation and control schemes

are:

1) Safer Plant Operation

a) To keep the process variables within known safe operating limits.

b) To detect dangerous situations as they develop and to provide alarms and automatic shut-

down systems.

c) To provide inter locks and alarms to prevent dangerous operating procedures.

2) Production Rate

To achieve the design product output.

3) Product Quality

To maintain the product composition within the specified quality standards.

4) Cost

P a g e | 91

To operate at the lowest production cost, commensurate with the other objectives.

These are not separate objectives and must be considered together. The order in

which they are listed is not meant to imply the precedence of any objective over another,

other than that of putting safety first. Product quality, production rate and the cost of

production will be dependent on sales requirements. For example, it may be a better strategy

to produce a better quality product at a higher cost.

In a typical chemical processing plant these objectives are achieved by a

combination of automatic control, manual monitoring and laboratory analysis.

7.3 Components of Control System

Process

Any operation or series of operations that produces a desired final result is a

process. In this discussion the process is the cracking of naphtha.

Measuring Means

Of all the parts of the control system the measuring element is perhaps the most

important. If measurements are not made properly the remainder of the system cannot

operate satisfactorily. The measured available is dozen to represent the desired condition in

the process.

ANALYSIS OF MEASUREMENT VARIABLES TO BE MEASURED

a) Pressure measurements

b) Temperature measurements

c) Flow Rate measurements

d) Level measurements

Variables to be Recorded

Indicated temperature, composition, pressure, etc.

Controller

The controller is the mechanism that responds to any error indicated by the error

detecting mechanism. The output of the controller is some predetermined function of the

error.In the controller there is also and error-detecting mechanism which compares the

P a g e | 92

measured variables with the desired value of the measured variable, the difference being the

error.

Final Control Element

The final control element. receives the signal from the controller and by some

predetermined relationships changes the energy input to the process.

7.5 Classification of Controller

In general the process controllers can be classified as:

a) Pneumatic controllers

b) Electronic controllers

c) Hydraulic controllers

In the ethylene manufacturing from naphtha the controller and the final control element may

be pneumatically operated due to the following reasons:

i) The pneumatic controller is vary rugged and almost free of maintenance. The maintenance

men have not had sufficient training and background in electronics, so basically pneumatic

equipment is simple.

ii) The pneumatic controller appears to be safer in a potentially explosive atmosphere which

is often present in the petro-chemical industry.

iii) Transmission distances are short. Pneumatic and electronic transmission system are

generally equal upto about 250 to 300 feet. Above this distance, electronic systems begin to

offer savings.

7.6 Modes of Control

The various type of control are called "modes" and they determine the type of

response obtained. In other words these describe the action of the controller that is the

relationship of output signal to the input or error signal. It must be noted that it is error that

actuates the controller. The four basic modes of control are:

i) On-off Control

P a g e | 93

ii) Integral Control

iii) Proportional Control

iv) Rate or Derivative Control

In industry purely integral, proportional or derivative modes seldom occur alone in

the control system.

The On-off controller in the controller with very high gain. In this case the error

signal at once off the valve or any other parameter upon which it sits or completely sets the

system.

7.7 Alarms and Safety Trips and Interlocks

Alarms are used to alert operators of serious, and potentially hazardous, deviations

in process conditions. Key instruments are fitted with switches and relays to operate audible

and visual alarms on the control panels.

The basic components of an automatic trip systems are:

i) A sensor to monitor the control variable and provide an output signal when a preset valve

is exceeded (the instrument).

ii) A link to transfer the signal to the actuator usually consisting of a system of pneumatic or

electric relays.

iii) An actuator to carry out the required action; close or open a valve, switch off a motor. -

A safety trip can be incorporated in control loop; as shown in figure . In this system the

high-temperature alarm operates a solenoid valve, releasing the air on the pneumatic

activator closing the valve on high temperature.

Interlocks

Where it is necessary to follow the fixed sequence of operations for example,

during a plant start-up and shut-down, or in batch operations-inter-locks are included to

prevent operators departed from the required sequence. They may be incorporated in the

control system design, as pneumatic and electric relays or may be mechanical interlocks.

P a g e | 94

7.8 Different Type of Controllers

Flow Controllers

These are used to control feed rate into a process unit. Orifice plates are by far the

most type of flow rate sensor. Normally, orifice plates are designed to give pressure drops in

the range of 20 to 200inch of water. Venture tubes and turbine meters are also used.

Temperature Controller

Thermocouples are the most commonly used temperature sensing devices. The

two dissimilar wires produce a millivolt emf that varies with the "hot-junction"temperature.

Iron constrictant thermocouples are commonly used over the 0 to 1300°F temperature range.

Pressure Controller

Bourdon tubes, bellows, and diaphragms are used to sense pressure and differential

pressure. For example, in a mechanical system the process pressure force is balanced by the

movement of a spring. The spring position can be related to process pressure.

Level Controller

Liquid levels are detected in a variety of ways. The three most common are:

Following the position of a float, that is lighter them the fluid.

Measuring the apparent weight of a heavy cylinder as it buoyed up more or less by

the liquid (these are called displacement meters).

Measuring the difference in static pressure between two fixed elevations, one in the

vapour above the liquid and the other under the liquid surface. The differential

pressure between the two level taps is directly related to the liquid level in the vessel.

Transmitter

The transmitter is the interface between the process and its control system. The job

of the transmitter, is to convert the sensor signal (millivolts, mechanical movement, pressure

differential, etc.) into a control signal 3 to 15 psig air-pressure signal, 1 to 5 or 10 to 50 milli

ampere electrical signal, etc.

P a g e | 95

Control Valves

The interface with the process at the other end of the control loop is made by the final

control element is an automatic control valve which throttles the flow of a stem that open or

closes an orifice opening as the stem is raised or lowered. The stem is attached to a

diaphragm that is driven by changing air-pressure above the diaphragm. The force of the air

pressure is opposed by a spring.

7.9 Control Schemes of Distillation Column

GENERAL CONSIDERATION

Objectives

In distillation column control any of following may be the goals to achieve

1. Over head composition.

2. Bottom composition

3. Constant over head product rate. .

4. Constant bottom product rate.

Manipulated Variables

Any one or any combination of following may be the manipulated variables

1. Steam flow rate to reboiler.

2. Reflux rate.

3. Overhead product withdrawn rate.

4. Bottom product withdrawn rate

5. Water flow rate to condenser.

7.10 Loads or Disturbances

Following are typical disturbances

1. Flow rate of feed

2. Composition of feed.

3. Temperature of feed.

P a g e | 96

4. Pressure drop of steam across reboiler

5. Inlet temperature of water for condenser.

7.11 Control Scheme

Overhead product rate is fixed and any change in feed rate must be absorbed by

changing bottom product rate. The change in product rate is accomplished by direct level

control of the reboiler if the stream rate is fixed feed rate increases then vapor rate is

approximately constant & the internal reflux flows must increase.

ADVANTAGE

Since an increase in feed rate increase reflux rate with vapor rate being approximately

constant, then purity of top product increases.

DISADVANTAGE

The overhead reflux change depends on the dynamics of level control system that adjusts it.

Figure: Control scheme

P a g e | 97

8.Materials of Construction Any engineering design, particularly for a chemical process plant, is only useful

when it can be translated into reality by using available materials of construction combined

with the appropriate techniques of fabrication can play a vital role in the success or failure

of a new chemical plant.

8.1 Corrosion In Brewery Industry

Breweries are unique in many aspects in the food-processing industry. The product

and its production as well as cleaning procedure, storage, and bottling, all use great

quantities of water. They require a large amount of tankage and extensive hot water

facilities. Furthermore, the product is an acidic liquid that is aggressive to low-carbon steel.

This is further complicated that the presence of iron ions in the product drastically affects its

shelf life.

Wet, damp, and high-humidity conditions all contribute to plant corrosion and

premature equipment failure if not properly treated. These factors make the typical brewery

a challenge to the corrosion engineer. A brewery materials engineer must be familiar with

the materials of construction for all of this equipment and must also be aware of diverse

corrosion control techniques involving coatings, metals, cathodic protection, plastics and

even the use of inhibitors.

8.2 Corrosion Control Methods

As in any other industry there are always several ways to solve a given material

problem in the brewery. The task of the materials (corrosion) engineer is to sort out the

available choices and to arrive at the most cost-effective solution to the problem.

Traditionally, brew masters, who at one time exercised, employed set conditions for

plant equipment, such as wood with wax linings (tanks with slotted or perforated false

bottoms used for filtering clear liquid from the grain mash) for fermentation and storage,

copper for kettles and lanter tubes, and low carbon steel for pasteurization.

In our plant corrosion is controlled by coating the equipments with paints.

P a g e | 98

8.3Important Material Available

Material of construction may be divided into two general classification of metals

and non-metals. Pure metals and metallic alloys are included under the first classification.

1) Iron and Steel

Although many materials have greater corrosion resistance than iron and steel cost

aspects favor the use of iron and steel. As a result they are often used as a material of

construction when it is known that some corrosion will occur. If this is done the presence of

iron salts and discoloration in the product can be expected and periodic replacement of the

equipment should be anticipated. In general, cost of iron and carbon steel exhibit about the

some corrosion resistance. They are not suitable for use with dilute acids, but can be used

with many strong acids; since a protective coating composed of corrosion products forms on

the metal surface.

2) Stainless Steel

There are more than 100 different types of stainless steels. The main reason for

the existence of stainless steels in their resistance to corrosion. Chromium is the main

alloying element, and the steel should contain at least 11%. Chromium is a reactive element

but it and its alloys passivity and exhibit excellent resistance to many environments. A large

number of steels are available. So stainless steel contains chromium, nickel, iron, and also

containing small amount of other essential properties. They have excellent corrosion

resistance and heat-resistance properties. Most of the brewery equipment currently being

installed is fabricated from A1S1 type 304 stainless steel.

3) Nickel and its Alloy

Nickel exhibits high corrosion resistance to most alkalies.' Nickel-clad steel is

used extensively for equipment in the production of caustic soda and alkalies. The strength

and hardness of nickel is almost as great as carbon steel. In general, oxidizing conditions

promote the corrosion of nickel, and reducing conditions retard it. Monel, an alloy of nickel

containing 67% nickel and 30% copper is often used in food industries. This alloy is

stronger than nickel and has better corrosion resistance properties than either copper or

nickel.

P a g e | 99

4) Copper

It has been the traditional metal in breweries for centuries, but with the

advent of new alkaline cleaner, some corrosion problems have occurred. Copper and copper

base alloys are used in the formation of heat exchanger tubing, piping, fittings, etc.

Although the corrosion rates are comparatively high. In the range from room temperature

upto 100°C, the corrosion rate of copper is comparatively small. However, the corrosion

rate of 100°C is about five times that which takes place at room temperature.

5) Aluminium

The lightness and relative ease of fabrication of aluminum and its alloys are

factors favoring the use of these materials. Aluminium resists attack by acids because a

surface film of inert hydrated aluminium oxide is formed. This film adheres to the surface

and offers good protection unless materials which can remove the oxide, such as hydrogen

acids or alkalies are present.

6) Land

Pure lead has low creep fatigue resistance, but. its physical properties can

be improved by the addition of small amounts of silver, copper, antimony or tellurium.

Lead-clad equipment is in common use in many chemical plants. Lead shows good

resistance to sulfuric acid and phosphoric acid but it is susceptible to attack by acetic acid

and nitric acid.

7) Hastelloy

The beneficial effects of nickel, chromium, and molybdenum arc combined

in Hastelloy C to give an expensive but highly corrosion-resistant material. A typical

analysis of this shows 56% nickel, 17 molybdenum, 16% chromium, 5% iron and 4%

tungsten with manganese, silicon, carbon, phosphorus, and sulfur making up the balance.

Hastelloy C is used where structural strength and good corrosion resistance are necessary

under conditions of high temperature. The material can be machined and is easily

fabricated.

P a g e | 100

8) Coatings

Breweries are large consumer of quality coatings, not only for tankage but also for

structural steel, flooring and other working areas. The coating used range from high heat

silicones for stacks to special super resistant grouts for floor pavers.

9) Floor Materials

Considerable giazod tile is used in breweries and special expoxies with good

adhesion to very smooth surfaces have employed to coat glazed ceramic tile in order to

prevent crazing (cracking).Bacterial contamination deep in the pores of the concrete is a

common occurrence. If floors are not properly sealed, corrosion of concrete rebars and

structural steel can result, with eventual cracking and spalling of concrete.

10) Plastics

For corrosion control point of view, plastics materials are very useful,

therefore they have found application in breweries, water treatment tanks, acid storage,

roofing, and gutters are application for plastics that are common to most industrial activity.

Fiberglass and polyvinyl chloride are among the plastics that have been employed. Small

polypropylene tanks for yeast culture and other specialty service have some record of use.

8.4 Sulfuric Acid Handling Materials

Mild steel is widely used for the handling of sulfuric acid in concentration

over 70% storage tanks, pipelines, tank cars, and shipping drums made of steel are very

common for 78% (60 B6), 93% (66Be), 98% and stronger acids such as oleum. Pumps and

valves are often made of high-alloy material such as type 316 stainless steel because of

erosion corrosion of steel. Much of the equipments are made of mild steel. Steel is attacked

rapidly by more dilute sulfuric acids. Most of the, tests were made on ordinary steel of 0.2%

carbon.

Mild steel would not be generally suitable in concentration below 65% at

any temperature. Above 70% concentration this type of steel can be used, depending on

temperature.

P a g e | 101

Mild steel is also generally unsatisfactory for handling suifuric acid from 100

to 101 with the oleum range.

Although the stainless steel may be used safely in contact with 80 to 100%

sulfuric acid at ambient temperature (carbon steel is ordinarily used in this range), they are

attacked slightly high temperature. One to 5% sulfuric acid at ambient temperature overtone

should not be stored molybdenum-free stainless steel. Type 316 may be used for this

purpose.

*Note: Baume Scale: [A scale of relative density (specific gravity) of liquids, Named after

A. Baurn6 (1728-1804). Degrees Baume = 144.3 (r.d.- l)r.d.]

8.5 Recommended Materials Of Construction

Maliec anhydride when pure shows corrosive action upto its boiling point

temperature. Therefore, special material of construction used in the production and handling

of maliec anhydride. Pure maliec anhydride is probably less corrosive toward stainless

steel .

Although many materials have greater corrosion resistance than carbon steel,

cost aspects favor the use of carbon steel. As a result they are often used as material of

construction when it is known that some corrosion will. All the major equipments of

"industrial malice anhydride" is recommended to be manufactured by carbon steel; some

equipments where conc. H2SO4 and dilute acid used stainless steel 304 or 316 are used

otherwise lining of corrosion resistance material can be used. So recommended material of

construction is stainless steel.

P a g e | 102

9. Plant Layout

Plant layout is the functional arrangement of machinery and equipment in a

existing plant. Plant layout may be defined as the floor plan for determining and

arranging the desired equipment of a plant, in the one best place, to permit the quickest

flow of materials at lowest cost and least amount of handling in processing the raw

material from the receipt of raw material to the shipment of finished products.

The material handling planned in the layout begins at the receiving point,

where the material arrives as raw material, then continuous progressively from storage

through process, moving the form of worked material from department to department,

from machine to machine ,the material flows in and out of temporary storage is fed

through assembly lines for final assembly. Provision is made for inspection, packaging

and storing the material as finished product.

Advantages of good plant layout to the workers :

• Reduces the effort of the workers.

• Reduces the number of handling.

• Permits working at maximumefficiency.

• Reduces the number of accidents.

• Provides basis for higher earnings.

Advantages of a good plant layout in labour cost:

• Increases output per man hour.

• Reduces number of operators.

• Loss setup time involved

Advantages of a good plant lay out in production control:

• Reduces production control expenses

• Pace production

\

P a g e | 103

Fundamental concepts of plant layout:

In apprising the advantages of good layout in the light of conditions

prevailing in a particular plant, it is well to bear in mind the following concepts of

plant layout.

• Majorpartofproductionworksisnotprocessing,asisinitiallysupposebut material

handling.

• Then speed of production in the plant is determined primarily by the

adequacies of its material handling facilities.

• A good plant layout is designed to provide the proper facility for material

handling.

• The factory is altered or constructed around the prescribed plant layout.

• Theproductionefficiencyoftheplantisdeterminedbythelimitationsofits layout.

TYPES OF DEPARTMENT

• Processing department.

• This department performs machining assembly and packaging.

• Service department.

• These constitute the facilities provided to keep the processing department in

operation without interruption.

• Administrative department.

• This department administrative sales, engineering, accounting production

control, departments etc.

PLANNING THE PROCESSING

• Theplantlayoutengineershouldobtaindataonbuildingelevation,column spacing,

door and conveyors.

• The conveyors should be placed at reasonable height to malfunctioning and

waste.

• The traffic in the plant may be greatly by location store rooms close to the

building entrances.

P a g e | 104

• In addition to the above vehicular traffic should be separated from pedestrian

traffic and the roads should be wider.

PLANNING THE PLANT SERVICE FACILITIES:

•Materialreceivedataplantarrivesviatheparticularformsoftransportation which are

generally prescribed.

• Liquids such as chemicals are transported in tank cars, drums or pipelines

•Thereceivingdepartmentmustbewellequippedtoreceivethematerialinall modes.

• The design of a receiving involves the followingconsiderations:

1. Space, 2. Climate conditions, 3. Variety of vehicles

STOREROOM:

• A store roomis the reservoir for raw material.

• Worked materials, finished products, maintenance supplies etc are kept.

• The functional requirements of a store roomare:

1. protection tomaterials

2. handling of the materials

3. control points

The above factors also help the layout engineer to design the store room as per

requirements.

INSPECTION ROOM:

•The inspection room or quality control room should be located near the

production unit, so that the samples from the production plant Can be checked

for its quality requirements.

• The labs should be well equipped and should be properly planned.

WATER STORAGE:

• Water is used in the plant for variety of purposes.

• A plant must have adequate water supply to crater all these needs.

P a g e | 105

•By far the most reliable and effectives means of fire protection is the automatic

sprinkler system.

•The sprinkler system is fitted with a sensitive transducer which lets water up to a

height of 15 feet.

• So the water storage system should be planned out with most care.

POWER AND LIGHTINGSYSTEM:

• Power and lighting systems forms the main part of the plant.

• The significant features of the power plant operations are,

1. For supplying steam.

2. Providing heat for process operations.

3. supplying power to run motor.

4. providing light to plant.

5. power for surplus use.

PLANNING OF ADMINISTRATIVE BLOCK:

•Location of an administrative block depends upon the geographic location with

respect to the plant functions.

•The general administrative block should have administrative rooms, conference

room and vault room storage of documents and records.

•The employee service facility consists of parking lots, Employment office

cafeteria, first aid stations and medical department etc. ref[6]

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Plant layout

P a g e | 107

10. Economic Analysis An acceptable plant design must present a process that is capable of operating

under conditions which will yield a profit.

It is essential that chemical engineer be aware of the many different types of

cost involved in manufacturing processes. Capital must be allocated for direct plant

expenses; such as those for raw materials, labor, and equipment. Besides direct

expenses, many other indirect expenses are incurred, and these must be included if a

complete analysis of the total cost is to be obtained. Some examples of these indirect

expenses are administrative salaries, product distribution costs and cost for interplant

communication.

10.1 Estimation of Equipment Cost

Total income-All expenses= Net profit

Equipment Cost (Rs.)

Exchanger E-101 154427

Exchanger E-102 183702

Condenser E-103 175501

Reactor R-102 193459

Re-boiler E-104 938765

Reactor R-101 5400000

Distillation Column T-102 2982000

Flash vessel V-101 120000

Absorber T-101 4431117

P a g e | 108

10.2 Estimation of Total Capital Investment

Direct Cost (Rs)

Purchased equipment cost = Rs. 14578971

Purchased equipment installation = 0.47× 14578971 = Rs. 6852116.37

Instrumentation & Process Control = 0.12 × 14578971 = Rs. 1749476.52

Piping (installed) = 0.66 × 14578971 = Rs. 9622120.86

Building (Including Services) = 0.18×14578971 = Rs. 2624214.78

Yard improvements = 0.1 × 14578971 = Rs. 1457897.1

Service facilities (installed) = 0.7 × 14578971 = Rs. 10205279.7

Land = 0.06 × 14578971 = Rs. 874738.26

Total direct plant cost = Rs. 47964904.6

Indirect Cost

Engg & Supervision = 0.33 × 14578971 = Rs. 4811060.43

Construction expenses = 0.41 × 14578971 = Rs. 5977378.1

Total Indirect Cost = Rs. 10788438.54

Total Direct & Indirect Cost = Rs. 58753343.14

Contractor’s fee = 0.05 × 58753343.14 = Rs. 2937667.157

Contingency = 0.1 × 58753343.14 = Rs. 5875334.3

Fixed Capital Investment = Total (direct +indirect) cost +contingency

+Contractor’sfee

= Rs. 67566344.6

Total Capital Investment = F.C.I + W.C.

Now

W.C = 0.15 (T.C.I)

P a g e | 109

= 0.15 (67566344.6 + W.C)

W.C = Rs. 11923472.58

T.C.I = 11923472.58+67566344.6

= Rs. 79489817.18

= 80 million rupees

P a g e | 110

11. Safety and Health Hazards & pollution Control11.1 Effects of Human Exposure

In many occupational situations workers are exposed to mixtures of acid

anhydrides, including maleic anhydride, phthalic anhydride, and trimellitic anhydride.

For example, Barker et al. (1998) studied a cohort of 506 workers exposed to these

anhydrides. In one factory, workers were exposed only to trimellitic anhydride, which

has the lowest acceptable occupational exposure limit (40 mg/m3) of the three

anhydrides. In that factory there was an increased prevalence of sensitization to acid

anhydride and work related respiratory symptoms with increasing full shift exposure

even extending down to levels below the current occupational standard. However,

none of the workplaces had exposure only to maleic anhydride and a doseresponse

relationship was not seen with mixed exposures. The following reports involve

exposure only to maleic anhydride.

There are several case reports describing asthmatic responses possibly resulting

from exposure to maleic anhydride. An individual showed an acute asthmatic reaction

after exposure to dust containing maleic anhydride (Lee et al., 1991). Workplace

concentrations of maleic anhydride were 0.83 mg/m3 in the inspirable particulate mass

and 0.17 mg/m3 in the respirable particulate mass. Bronchial provocation testing was

performed with phthalic anhydride, lactose, and maleic anhydride. Exposure of this

individual to maleic anhydride (by bronchial provocation testing) at 0.83 mg/m3 and

0.09 mg/m3 in inspirable and respirable particulate mass, respectively, showed a

response of cough, rhinitis, and tearing within two minutes. Within 30 minutes, rales

developed in both lungs and peak flow rate decreased 55%. An individual

occupationally exposed to maleic anhydride developed wheezing and dyspnea upon

exposure (Gannon et al., 1992). After a period without exposure, two re-exposures

both resulted in episodes of severe hemolytic anemia. There was no evidence of

pulmonary hemorrhage.Radioallergosorbent testing showed specific IgE antibodies

against human serum albumin conjugates with maleic anhydride, phthalic anhydride,

and trimellitic anhydride, but not with tetrachlorphthalic anhydride. A critique of the

Gannon et al. (1992) study by Jackson and Jones (1993) questions the relationship of

P a g e | 111

maleic anhydride exposure to the onset of the anemia, since there were extended

periods of exposure to maleic anhydride before symptoms appeared. Another case

report described occupational asthma due to exposure to maleic anhydride ..

Humans exposed to maleic anhydride showed respiratory tract and eye

irritation at concentrations of 0.25 to 0.38 ppm (1 to 1.6 mg/m3) maleic anhydride

(Grigor’eva, 1964). No irritation was reported at 0.22 ppm maleic anhydride.

11.2 Effects of Animal Exposure

Short et al. (1988) chronically exposed CD rats (15/sex/group), Engle hamsters

(15/sex/group), and rhesus monkeys (3/sex/group) to maleic anhydride by inhalation.

Four groups of each species were exposed to concentrations of 0, 1.1, 3.3, or 9.8

mg/m3 maleic anhydride for 6 (Determination of Non-cancer Chronic Reference

Exposure Levels Batch 2B December 2001 A – 67) Maleic anhydride hours/day, 5

days/week, for 6 months in stainless steel and glass inhalation chambers. Solid maleic

anhydride was heated to 53°C to generate vapors, which were then mixed with a

stream of nitrogen. Chamber target levels were monitored by gas chromatography as

total maleic (maleic anhydride plus maleic acid). No exposure-related increase in

mortality occurred. Of the species examined, only rats showed significant changes in

body weight during the course of the experiment, with reductions among males in the

high-dose groups after exposure day 40 and a transient weight reduction from days 78-

127 in the mid-dose group. All species exposed to any level of maleic anhydride

showed signs of irritation of the nose and eyes, with nasal discharge, dyspnea, and

sneezing reported frequently. No exposure-related eye abnormalities were reported.

The severity of symptoms was reported to increase with increased dose. No dose

related effects were observed in hematological parameters, clinical chemistry, or

urinalysis. No effects on pulmonary function in monkeys were observed. Dose-related

increases in the incidence of hyperplasic change in the nasal epithelium occurred in

rats in all exposed groups, and in hamsters in the mid- and high-dose groups.

Neutrophilic infiltration of the epithelium of the nasal tissue was observed in all

species examined at all exposure levels. All changes in the nasal tissues were judged

P a g e | 112

to be reversible. The only other significant histopathological observation was slight

hemosiderin pigmentation in the spleens of female rats in the high-dose group.

The teratogenicity and multigeneration reproductive toxicity of maleic

anhydride were also investigated (Short et al., 1986). To evaluate teratogenicity,

pregnant CD rats were treated orally with maleic anhydride in corn oil at

concentrations of 0, 30, 90, or 140 mg/kg-day from gestational days 6-15. Animals

were necropsied on gestational day 20. No statistically significant dose-related effects

were observed in maternal weight gain, implantation, fetal viability, post-implantation

loss, fetal weight, or malformations. Groups of 10 male rats and 20 female rats/group

(F0 animals) were orally treated with 0, 20, 55, or 150 mg/kg-day maleic anhydride in

corn oil to study multigeneration reproductive toxicity. Animals within the same dose

group were bred together after 80 days of treatment to produce two F1 generation

animals (F1a and F1b) and animals from the F1 generation were interbred to produce

two F2 generation animals (F2a and F2b). A significant increase in mortality was

observed among both F0 and F1 (Determination of Noncancer Chronic Reference

Exposure Levels Batch 2B December 2001A – 68) Maleic anhydride generation

animals in the high-dose group. Total body weight was significantly reduced in

animals in the high-dose group at Week 11 of exposure for the F0 generation males

and females and at Week 30 of exposure in the F1 generation males. No consistent

P a g e | 113

pattern of dose- or treatment-related effect on fertility, litter size, or pup survival was

observed. Examination of F0 animals showed necrosis of the renal cortex in the high-

dose group (60% of males and 15% of females). Absolute kidney weights were

significantly increased in F1 females in the low- and mid-dose groups, although there

was no histological correlate. No changes in organ weight or histology were observed

in the F2 generation animals.

11.3 Potential for Differential Impacts on Children's Health

Minimal teratogenic and reproductive adverse effects were seen at the lowest

oral dose of maleic anhydride (20 mg/kg-day), given to rats during gestation (Short et

al., 1986). This dose is equivalent to a person inhaling 70 mg/m3. Thus the chronic

REL of 0.7 μg/m3 should protect children. Maleic anhydride is a respiratory irritant

and an inducer of asthma. Exacerbation of asthma has a more severe impact on

children than on adults. However, there is no direct evidence in the literature to

quantify a differential effect of maleic anhydride in children.

Toxicology (This section is for information only and should not be taken as the basis

for OSHA policy).

Maleic anhydride is a severe irritant to the eyes, skin and respiratory tract

which can, upon exposure, produce intense burning sensations in the eyes and throat

with coughing and vomiting. Among workers repeatedly exposed to 5-10 mg/m3,

toxic effects included ulceration of nasal mucous membranes, chronic bronchitis, and

in some cases, asthma. Other potential effects of exposure are dermatitis, pulmonary

edema, respiratory sensitization, skin sensitization, photophobia and double vision.

(Ref. 5.2.)

11.4 Reliable quantitation limit

The reliable quantitation limit is 97 ng of maleic anhydride per sample or

0.005 mg/m3 based on the recommended air volume. This is the smallest amount of

maleic anhydride which can be quantitated within the requirements of 75% recovery

and 95% confidence limits of less than ±25%. (Section 4.2.)

P a g e | 114

11.5 First -Aid Measures

Ingestion

Do not induce vomiting. Have a conscious person drink several glasses of

water or milk. Seek immediate medical attention.

Inhalation:

Allow the victim to rest in a well ventilated area. Seek immediate medical

attention.

Skin Contact

After contact with skin, wash immediately with plenty of water. If irritation

persists seek medical attention. Wash contaminated clothing before reusing.

Eyes

Immediately flush with water for at least 15 minutes, keeping eyelids open. Seek

medical attention

FIRE FIGHTING MEASURES

Small fire: Carbon dioxide, water, foam.

Large fire: Water spray, fog or foam, do not use water jet.

Extinguishing Media:

11.7 Do Not Use Dry Chemical

Large volumes of gases could be produced by reaction with Maleic

Anhydride. Special Fire-Fighting Procedures: Wear self-contained breathing apparatus

with full face piece operated in the positive pressure demand mode and full body

protection when fighting fires. Hazardous Combustion Products: Carbon Dioxide,

Carbon Monoxide. Unusual Fire and Explosion Hazards: Unstable, or air-reactive or

water-reactive chemical involved Vapors from melted material can be ignited. Keep

melted material away from ignition sources. May form flammable dust-air mixtures

P a g e | 115

when finely divided. Prevent dust buildup by providing adequate ventilation during

grinding or milling Operations

11.8 Handling and Storage

Handling

Eye wash and safety shower should be available nearby when this product

is handled or used. Minimum feasible handling temperatures should be maintained.

Avoid generating mist or dust. Exercise care when opening bleeders and sampling

ports. Do not breathe gas, fumes, vapor or spray. Do not ingest. Avoid contact with

skin and eyes. After handling, always wash hands thoroughly with soap and water.

Storage Store away from incompatible materials.Store at temperatures not

exceeding 70°C (158°F). Contains moisture sensitive material -- store in a dry

place.

11.9 Exposure Controls/Personal Protection

Eye/Face Protection :

Avoid eye contact. Chemical type goggles with face shield must be worn.

Do not wear contact lenses.

Skin Protection

Protective clothing such as coveralls or lab coats must be worn. Gloves

resistant to chemicals and petroleum distillates required. When handling large

quantities, impervious suits, gloves, and rubber boots must be worn. Remove and dry-

clean or launder clothing soaked or spoiled with this material before reuse. Dry

cleaning of contaminated clothing may be more effective than normal laundering.

Inform individuals responsible for cleaning of potential hazards associated with

handling contaminated clothing. Respiratory Protection Airborne concentrations

should be kept to the lowest levels possible. If vapor, mist or dust is generated and the

P a g e | 116

occupational exposure limit of the product is exceeded, use appropriate NIOSH or

MSHA approved air purifying or air supplied respirator after determining the airborne

concentration of the contaminant. Air supplied respirators should always be worn

when airborne concentration of the contaminant or oxygen content is unknown.

11.10 Toxicological Information

Oral LD-50 (rat) 1030 mg/kg Dermal LD-50 (rabbit) 2620 mg/kg

Skin irritation (rabbit), corrosive Eye irritation (rabbit) extremely irritating

Sensitization. The limited number of animal studies investigating the dermal or

respiratory sensitization potential of maleic anhydride have not shown conclusive

evidence of sensitization potential. Although there have been reports of human dermal

or respiratory sensitization from maleic anhydride exposures, the number of reports

has been low when compared to the number of potentially exposed individuals. Maleic

anhydride has a low potential for human dermal or respiratory sensitization.

Effects of Acute Exposure Extremely dangerous in case of skin contact

(corrosive, irritant), of eye contact (irritant) and inhalation. Very dangerous in case of

ingestion. Slightly dangerous in case of skin contact (sensitizer). Eye contact can

result in corneal damage or blindness. Inhalation of dust will produce irritation to

gastro-intestinal or respiratory tract, characterized by burning, sneezing and coughing.

Effects of Chronic Exposure:

Carcinogenic effects Not available.

Mutagenic effects: Not available.

Teratogenic Effects: Not available.

Toxicity of the product to the Reproductive system: Not available.

Repeated exposure of the eyes to low level dust can produce

irritation. Repeated skin exposure can cause local skin destruction or dermatitis.

Repeated inhalation can cause a varying degree of respiratory irritation or lung

damage. Repeated exposure to a highly toxic material may produce general

deterioration of health by accumulation in one or many human organs.

P a g e | 117

11.11 Ecological Information

Aquatic Toxicity LC50 - 96hr 230 mg/liter (mosquito fish) practically

nontoxic. LC50 - 24hr 150 mg/liter (blue gill sunfish) practically nontoxic. Mobility

This product is not likely to volatilize rapidly into the air because of its low vapor

pressure. Bioaccumulative potential of this product is not expected to bioaccumulate

through food chains in the environment. Remarks this product will hydrolyze rapidly

to the acid. Expected to be slightly toxic to aquatic species because of acidity.

11.12 Disposal Considerations

Waste Disposal Methods Recycle if possible. Consult your local

authorities. This product has the RCRA characteristics of corrosivity, and is identified

under RCRA as Maleic Anhydride. If discarded in its present form, it would have the

hazardous waste numbers D002 and U147. Under RCRA, it is the responsibility of the

user of the product to determine, at the time of disposal, whether the product meets

RCRA criteria for hazardous waste. Remarks Do not allow to enter drains or sewers.

Do not allow to drain into surface waters.

P a g e | 118

12. References:

1. Zhou J, Wang LI, Wang CH, Chen T, Yu H, Yang Q (2005) Synthesis and self assembly of amphiphilic maleic anhydride–stearyl methacrylate copolymer.J Polymer 46:1157–11642. Nieuwhof R, Marcelis A, Sudholter E (1999) Side-chain liquid-crystalline polymers from the alternating copolymerization of maleic anhydride and 1-olefins carrying biphenyl mesogens. J Macromol . 32:1398–14063. Al-Sabagh A, Noor MR, Din EL, Morsi RE, Elsabee MZ (2009) Styrene-maleic anhydride copolymers esters as flow improvers of waxy crude oil. J Pet Sci Eng 62:139–1464. Zhu LP, Yi Z, Liu F, Wei XZ, Zhu BK, Xu YY (2008) Amphiphilic graft copolymers based on ultrahigh molecular weight poly(styrene-alt-maleic anhydride) with poly(ethylene glycol) side chain for surface modification of polyethersulfone membranes. Eur Polym J 44:1907–19145. Nieuwhof R, Koudijs A, Marcelis A, Sudholter E (1999) Modification of sidechainliquid-crystalline poly(maleic anhydride-co-alt-1-alkene

6. Merck Index, 11th Edition, 5586.

7. Kurt Lohbeck; Herbert Haferkorn; Werner Fuhrmann; Norbert Fedtke (2005), "Maleic and Fumaric Acids", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a16_053

8. Samuel Danishefsky, Takeshi Kitahara, and Paul F. Schuda (1983). "Preparation and Diels-Alder Reaction of a Highly Nucleophilic Diene: trans-1-Methoxyl-3-Trimethylsiloxy-1,3-Butadiene and 5β-Methoxycyclohexan-1-one-3β,4β-Dicarboxylic acid Andhydride". Org. Synth. 61: 147.

9. Horie, T.; Sumino, M.; Tanaka, T.; Matsushita, Y.; Ichimura, T.; Yoshida, J. I. (2010). "Photodimerization of Maleic Anhydride in a Microreactor Without Clogging". Organic Process Research & Development 14 (2): 100128104701019

10. "Substance Evaluation Report: Maleic anhydride". Environment Agency Austria.

11. "Tainted starch found in Tainan yet again". Want China Times. 2013-12-19.12. Felder, R. M. and R. W. Rousseau, Elementary Principles of Chemical Processes (3rd ed.), Wiley, New York, 2000.13. Wankat, P., Equilibrium Staged Separation Processes, Prentice Hall, Upper Saddle

River, NJ, 1988.14. The Properties of Gases and Liquids, Fifth Edition Bruce E. Poling, JohnM. Prausnitz, John P. O’Connell15.Chemical process design by Coulson__Richardsons-vol-6, 4th edtn , pg 34-90616. Plant Design &Economics for Chemical Engineers-Peters Timmerhaus, fourth edition,ch-6(pg 226-350)

17.Chemical process Design by M.V.Joshi,4thedition,pg-220 to300