Fundamentals of Petrochemicals Presented by Umar Raja 25th May

2011

Introduction

· Mr Umar Raja, Principal Process Engineer

Umar has over 20 years experience in developing concept and detail design with an ability to see them through start-up, operations and operations management.

· The goal of today's workshop is to quickly and effectively bring you up to speed with the language, concepts and key issues in the petrochemical industry. It has been designed for managers, engineers, graduates, operators and other personnel who are new or are requiring insight into the Refining and Petrochemicals industry.

· The workshop will provide an excellent overview for people from technical, non-technical and commercial backgrounds, who have limited experience and wish to improve their familiarity with some of the systems and technologies involved.

Summary

· Chemical Industry· Oil Refineries & Petrochemical Refineries · Feed Stocks & Products · Basic Building Block Chemicals · Process Flow Configuration· Hands-on Session - Constructing simplified flow-schemes· Major Processes: Separation, Reaction, Equipment and

Environment· The Petrochem business? · Role of Engineers· Challenges in the Chemical Industry· Where can I get more information· Workshop Summary & Questions

The Chemical Industry

· Chemical products made from gas and crude oil (~70000 products)

· End products include plastics, soaps, detergents, solvents, paints, drugs, fertilizer, pesticides, explosives, synthetic textile fibres and rubbers, flooring and insulating materials and much more.

· The largest petrochemical manufacturing industries are to be found in the United States, Western Europe, Asia and the Middle East.

· In 2007, 2,980 operating plants worldwide

· 10 Million direct employees, 50 million indirect employees

· Annual growth rate 2.4 %. Global enterprise valued at $2.2 Trillion …… and growing!

Refining -The Mother Industry

5-6%

Petrochemical Refinery

THE PURPOSE OF A PETROCHEM REFINERY IS TO TRANSFORM RELATIVELY LOW VALUE PRODUCTS FROM OIL REFINERY INTO HIGH VALUE PRODUCTS

AS EFFICIENTLY, PROFITABLY AND ENVIRONMENTALLY SOUND A WAY AS POSSIBLE

Petrochemical Refinery

Feed Stocks & Products

Feed Stocks & Products

Chemical Industry- Product Pattern

Basic Building Blocks

The term ‘aromatics’ is typically used to describe· Benzene · Toluene · Xylenes These are commonly referred to as BTX aromatics and are produced in a

refinery or petrochemicals complex

The term ‘olefins’ is used to describe molecules with a C double bond· Ethylene · Propylene · Butenes or Butadiene These are commonly referred to as light olefins and are also produced in a

refinery or petrochemicals complex

Olefins and aromatics are very high-value products· Prices have reached over 1,000 $ / tonne for Paraxylene and benzene

Ethylene and propylene. Compared to naphtha at 40-60% of this value

Basic Building Blocks- Aromatics

Benzene, C6H6 , colourless and highly flammable liquid

· Carcinogen, additive in gasoline now limited· Building block for over 250 products

e.g.. Ethyl benzene (for styrene), Cumene (for phenol), Cyclohexane

Basic Building Blocks- Aromatics

Toluene (Methylbenzene), C7H8 or C6H5CH3, is a clear, water-insoluble liquid

· Produces benzene and xylenes · Toluene for toluene diisocyanate (TDI), manufactures

polyurethane· Produces phenol, caprolactam, nitrobenzene, benzoic

acid . · Octane booster in gasoline · 50% produces benzene and xylenes, 25% in solvents and

10% in the TDI. Around 15% of demand is by gasoline.[1] www.icis.com

Basic Building Blocks- Aromatics

Paraxylene (p-Xylene), C8H10, is colourless and a flammable liquid

· Isomers are O-xylene and M-xylene · One of the fastest growing petrochemicals · p-Xylene is used for PTA, DMT and PET for polyester · High purity needed for polymerisation process

Basic Building Blocks- Aromatics

Basic Building Blocks- Aromatics

Basic Building Blocks - Olefins

Ethylene, C2H4, is a gaseous organic compound

· Simplest Olefin Chemical feedstock· Most produced organic compound · 90% used to produce three chemical compounds

− ethylene oxide− ethylene dichloride− ethylbenzene− polyethylene

Basic Building Blocks - Olefins

Basic Building Blocks - Olefins

LDPE produces containers, dispensing bottles, tubing, plastic bags. Other products made from it include:

• Food storage and laboratory containers

• Parts that require flexibility, for which it serves very well

Parts of computer hardware, such as hard disk drives, screen cards, and optical disc drives

Basic Building Blocks - Olefins

HDPE is resistant to solvents and has a wide variety of applications, including:

• Plastic lumber

• Folding tables/chairs

• Storage sheds

• Chemical-resistant piping systems

• Water pipes, for domestic water supply

• Refillable bottles

• Bottle Caps

Basic Building Blocks - Olefins

Butadiene, C4H6

· Main intermediate for polymer production· Product of steam cracking· Light feeds, give primarily ethylene and heavier feeds form heavier

olefins, butadiene, and aromatic hydrocarbons. · Most butadiene is used in styrene-butadiene rubber (BDR)

production for the tyre industry (~28%)· Other polymers include Polybutadiene (PB), styrene-butadiene

latex (SBL), acrylonitrile-butadiene-styrene (ABS)

Basic Building Blocks - Olefins

shoe heels and soles, gaskets and

even chewing gum.

Musical instruments golf club heads (due to its good shock absorbance), automotive trim components, automotive bumper bars, enclosures for electrical and electronic assemblies, protective headgear, whitewater canoes, buffer edging for furniture and joinery panels, luggage, small kitchen appliances, and toys, eg. Lego bricks

Basic Building Blocks - Olefins

Propylene, C3H6

· Converts to acetone and phenol via the cumene process· Produces isopropanol (propan-2-ol), acrylonitrile.· Separated by distillation from hydrocarbon mixtures.· Products include plastic items for medical/laboratory,

kettles, food containers, clear bags and ropes.

PARAXYLENE1655 kta

BENZENE258 kta

CUMENE407 kta

ACETONE186 kta

CUMENE

PHENOL

NAPH

T HA

CRAC

KER

BENZENE780 kta

HYDROGENATEDPYGAS PYGAS

C5 ST

REAM

PROP

YLEN

E

Polypropylene

MEG

EOAEO

HDPE

MELAMINEUREA

ASU

LLDPE

MEDIUM - HEAVYNAPHTHA PROPYLENE10 kta

PP440 kta

MEGDEGTEG

ARGON

MEADEATEA

HDPE

UREALLDPE

ARGO

N

CO2E O

N2

ETHYLENE

BUTENE-1

N2 TOUTILITIES

AMMONIA

CO2

RECYCLE STREAMSMTBE

BUTADIENE

METHANOL

LT. NAPHTHA

HYDR

OGEN

OFFGASLPG

LT. NAPHTHAREFFINATE

PHENOL300 kta

UREA

522 kta

AROM

ATIC

SCO

MPLE

X

PYGASHYDRO

GENATION

CO2 R

ECOV

E RY

AMMONIA SYN.

O2

AMMONIA

MELAMINE

MTBEBUTADINE

Petrochemical Refinery – Flow Configuration

Major Processes – Aromatics Complex & Naphtha Cracker

Paraxylene1400 Kta

Benzene932 Kta

Medium/HeavyNaphtha2923 Kta

Naphtha Cracker

DeC5’d Pygas440 Kta

Light Naphtha3489 Kta

Propylene720 Kta

Ethylene1440 Kta

MTBE185 Kta

Butadiene200 Kta

C2/C3 Cut 162 Kta

LPG 291 Kta

L.t Naphtha 308 Kta

H2 92 Kta H2 35 Kta

H2 Export 127 Kta

Heavy Aromatics26 Kta

Tail Gas85 Kta

Butene 154 Kta

Toluene0 Kta

• Catalytic reformer for aromatics

� Feeds are heavy naphtha

� 60-70% yield of aromatics

� Up to 5% benzene, more in dedicated ‘benzene reformers’

• Steam cracker for olefins

� Feeds are ethane, propane, C4s,

naphtha

� 50-80% yield of olefins, 2–13% yield

of BTX

Aromatics Complex

Aromatics Complex - Overview

The following processes recover aromatic compounds from mixture

· Distillation· Extraction· Purification

The following processes convert lower-value aromatics into higher value aromatics

· Xylene isomerisation· Toluene conversion· C9+ aromatics conversion

Aromatics Complex - Overview

· Distillation won’t separate aromatics from non-aromatics due to the similar boiling points

· Aromatic are extracted from non-aromatic using either− Solvent extraction (liquid-liquid extraction)− Extractive distillation− Hybrid extraction (combination of the two)

· Purification of paraxylene from other C8 aromatics when not achieved by distillation uses following two techniques− Crystallisation exploits wide differences in freezing

points− Adsorption exploits differences in molecular shapes

Aromatics Complex - Production Processes

· Catalytic Reformer Operation with high catalyst activity to increase reformate aromatic yields from 50% to 75%

· UDEX Process (UOP Dow Extraction)

Aromatic rich feed with solvent removes non Aromatics in raffinate stream and aromatics in extract stream.

· SulfolaneTM Process similar to the UDEX but uses internal recycle streams to enhance separation and aromatic recovery

· Sulfolane by Shell Oil Company in the early 1960s is still the most efficient solvent available for the recovery of aromatics.

Aromatics Complex - Production Processes

Aromatics Complex - SulfolaneTM Process

Aromatics Complex - Chemical Transformations

· Toluene conversion into xylenes or benzene can be classified into 3 categories depending on the feed:

− 100% toluene feed− Toluene together with C9 and heavier aromatics− Toluene plus methanol

Toluene Hydrodemethylation to convert toluene to benzene

− Highly exothermic, hydrogen atmosphere to suppress coke formation

− Demethylation of occurs at about 650°F and 82barg

Aromatics Complex - Chemical Transformations

+

P-xylene

H2O+ CH3OH

· Toluene hydro de-alkylation

· Toluene methylation: Toluene and methanol

+

benzene

CH4+ H2

Aromatics Complex - Chemical Transformations

Toluene Disproportionation to convert toluene to benzene and xylene

· 2 moles of toluene into 1 mole of benzene and 1 mole of xylene

· Catalyst transfers methyl group from one methylbenzene ring to another methylbenzene ring

· Expensive than hydrodemethylation. · Involves hydrogen as reaction mixture is equilibrium

limited.

Aromatics Complex - Chemical Transformations

2 +

Mixed xylene Benzene

Aromatics Complex - Chemical Transformations

Process in which mixed C8 aromatics depleted in paraxylene are isomerised to produce more paraxylene

There are two types of xylene isomerisation· Ethylbenzene (EB) isomerisation

· Ethylbenzene (EB) dealkylation

The reaction path is dependent on catalyst used

Aromatics Complex - Chemical Transformations

C2H5

+ H2

C2H5

+ H2

+ C2H6

Mixed xylenes

Benzene

Xylene Isomerisation Process· Feed and hydrogen are preheated to reaction

temperature· Isomerisation reactor is a fixed bed down flow vessel

operating at temperatures of 450C and 31barg · Deheptanizer separates isomerised product as the

bottoms stream

Aromatics Complex - Chemical Transformations

Aromatics Complex – Selective Adsorption

· Isomers boil closely and conventional distillation is not practical.

· Parex process simulates a moving bed of adsorbent

· Separation takes place in the adsorbent chambers.

· 99.9 wt-% pure para-xylene at 97 wt-% recovery per pass

Parex process to separate Paraxylene from Xylene mixtures

Naphtha Steam Cracking – olefins

The feedstock is heated to the point that the energy transfer from heat is enough to ’crack’ the molecule into two or more smaller molecules.

• High heat input

• Mixture HC and steam passed through tubes inside a furnace

• Very Short Residence Time <1s

• Rapid Quench of reaction followed by distillation.

• 50-80% yield of olefins, 2–13% yield of BTX

Naphtha Steam Cracking – Overview

Hands on Session

1) The petrochemicals may be olefins or their precursors, or various types of ________ petrochemicals.

2) An ________ _______ is a combination of process units which are used to convert _________, from a variety of sources, and ___________ into the basic petrochemical intermediates: ______, ______, and ______.

3) Aromatics can be produced from variety of different feedstocks, including ______, _______, ________, and ___________.

4) Fill in the missing components for polystyrene production

______________ ______________ _______________ Polystyrene

Hands on Session

5) Fill in the missing process link

6) Traditional _________ won’t separate aromatics from non-aromatics due to _____ _____ ______. Aromatic components can be extracted from non-aromatic components using ____ _____ or _______ _______.

7) The two processes used to purify paraxylene from other C8 aromatics are ___________ and ___________.

8) _____________ exploits wide differences in freezing points and adsorption exploits differences in _________ ___________.

9) Toluene via ____________ or __________with C9-aromatics can produce _____ and an equilibrium mixture of xylenes.

Ethylene, propylene,Butenes & butadiene

Naphtha(80-110 C)

?

Hands on Session

10) Fill in the missing processes and components for the aromatic complex block flow below:

?

?

?

Gas

? Toluene

?

C9 Aromatics

TADP

Separation

?

Metaxylene

Isomerisation

?O-xylene / M-xylene separation

?O- xylene

Hands on Session

1) The petrochemicals may be olefins or their precursors, or various types of ________ petrochemicals.

2) An ________ _______ is a combination of process units which are used to convert _________, from a variety of sources, and ___________ into the basic petrochemical intermediates: ______, ______, and ______.

3) Aromatics can be produced from variety of different feedstocks, including ______, _______, ________, and ___________.

4) Fill in the missing components for polystyrene production

______________ ______________ _______________ PolystyreneBenzene Ethylbenzene Styrene

Ethylene

Aromatic

Aromatics Complex

Naphtha

Py Gas Benzene

Toluene Xylene

Naphtha LPG Condensate Py Gas

Hands on Session

5) Fill in the missing process link

6) Traditional _________ won’t separate aromatics from non-aromatics due to _____ _________. Aromatic components can be extracted from non-aromatic components using ____ _____ or _______ _______.

7) The two processes used to purify paraxylene from other C8 aromatics are ___________ and ___________.

8) _____________ exploits wide differences in freezing points and adsorption exploits differences in _______________.

9) Toluene via _____________ or ___________with C9-aromatics can produce _______and an equilibrium mixture of xylenes.

distillation

similar boiling points

solvent extraction

extraction distillation

crystallisation adsorption

crystallisation

molecular shapes

Ethylene, propylene,Butenes & butadiene

crackingNaphtha(80-110 C)

disproportionation transalkylation

benzene

Hands on Session

10) Fill in the missing processes and components for the aromatic complex block flow below:

Hydrotreating

Reformer

naphtha

GasToluene

Benzene

C9 Aromatics

TADP

Separation

Paraxylene Separation

Metaxylene

Isomerisation

P-xyleneO-xylene / M-xylene separation

O- xylene

Benzene Toluene Separation

Orthoxylene Separation

Reaction and Reactor

· Reaction- Process leading to transformation of one set of chemical substances to another.

· Reactor- Confines within which reaction occurs.

· Principal is not just confined to industrial reactors; but;

- Metabolic Processes in Living Organisms

- Atmospheric Chemistry.

Ideal, Batch and Flow Reactor

· Ideal Reactor- has uniform temperature, pressure and composition.

- In practice reactor temperature, pressure and composition are not uniform.

· Batch Reactor- Where reactor mass is not exchanged with surroundings

· Flow Reactor- Where reactor mass is exchanged with surroundings.

Adiabatic and Isothermal Reactor

Adiabatic Reactor- Where Reactor does not exchange heat with surrounding.

Isothermal Reactor- Where Reactor has good contact with surrounding but held at constant temperature (in both time and position within reactor).

CSTR or MFR

CSTR or MFR

Continuous Flow Stirred Tank Reactor OR Mixed Flow Reactor. Reaction occurs at constant pressure, constant temperature; and composition inside reactor is assumed to be that of effluent.

Tubular Reactor

Ideal Tubular or Plug Flow Reactor

Reactor operating isothermally and at constant pressure and at steady-state with unique residence time. Fluid fills the tube and moves like a plug down the length of the tube. Fluid properties are uniform over cross-section normal to direction of flow.

Industrial Reaction

What is expected from a Reaction?

Product of Choice

What is a Catalyst?

- Substance that enhances reaction without being consumed

2NH3

Reactants Products

Catalyst

Ammonia Synthesis

N2 + 3H2

Reaction and Catalyst

How long should a reaction take?- Fast to be economical

What is Economical?- Good value in relation to money, time and

effort

Ammonia is a cheap commodity, so catalyst must be cheap and durable! Lasts longer and produces 2000 times its value.

Industrial Reaction

If conversion is less what comes to mind?

How to dramatically improve it?

What are the factors?- Catalysts- Thermodynamics

Which of above is a primary Consideration?- Thermo is Primary- Catalyst is Secondary

Kinetics

Identification of Reaction

Elementary and Stoichiometric Reaction

H2+Br2 2HBr

Multi-step arrangement in Network (sequence/intermediates)Br+H2 → HBr + HH+Br2 → HBr + Br

Break or Make a single chemical bond. Must be written the way it takes place.

Environment - Water

Petrochemical Refinery environmental impacts on Water:

• process wastewater from desalting, distillation, cracking, and reforming operations

• about 24% of total emissions is released to wastewater

• large quantities of cooling water

Environment - Air

Petrochemical Refinery environmental impacts on Air: · volatile hydrocarbons from crude oil · SOx from crude oil and process heat

· NOx  and particulates from process heat

· H2S from sulfur recovery operations

· about 75% of total emissions by weight are released to air

Environment – Waste & Global Warming

Solid Waste

· Petrochemical plants generate significant amounts of solid waste and sludge , some of which is hazardous because of organics and heavy metals.

Contribution to Global warming

· energy-intensive operation · most of the energy is consumed as process heat · thus, little prospect for replacement of process energy by

renewable or non-CO2-intensive sources

Of great concern are accidental discharges as a result of abnormal operation.

Environment - Minimising Pollution

· Operate Furnaces Efficiently· Waste Material to Flare· Avoiding Spills and Accidental Releases· Water Treatment

Petrochemical Business

Price and quality of feedstock and products is constantly

changing.

Government regulations add additional constraints.

Not much differential between price of feedstock’s and products.

HOW DO I KEEP IN

BUSINESS?

· I need to design and revamp the plant utilizing the latest technology to be more efficient

· I need to make the plant more flexible and responsive · I need to operate (control) the plant in the most efficient

manner possible· I need to keep the equipment running all the time

I NEED ENGINEERS!

Petrochemical Business

Role of Engineers

· Operations & Maintenance Engineers· Control Systems Engineer· Design Engineer · Health & Safety · Environmental Impacts· Planning & Scheduling· Reliability Engineer· Plant Manager

Chemical Industry- The Challenges

· Feedstock availability and increasing cost

· Environmental controls e.g. increasing constraints on emissions

· Energy Savings· Process Efficiency · Catalyst Development · Increasing demand for

products

Workshop Summary

· Presented only some of the main processes in petrochemicals, others downstream are polymers, plastics, fibres and resins is extensive.

· A petrochemical refinery is made up of a combination of highly integrated processes such as distillation, extraction, and various separation operations.

· Olefins and aromatics are the building blocks for a wide range of materials and products

· Aromatic complexes is a general term for a combination of process units that produce the three basic chemicals

· Crackers convert feed-stocks into ethylene, propylene, butane, butadiene via cracking. 

Further Information

Books:

Speight, James. G. 2002, Chemical Process and Design Handbook

John Wiley & Sons. 2007 , Wiley Critical Content - Petroleum Technology, Volume 1-2

Chenier, P. 2002, Survey of Industrial Chemistry, Third Edition

Internet: Google Search, Online Books, Articles

Q & A

QUESTIONS

Summary

· Keywords –Language, Concept, Key Issues· Petrochemicals- Petrochemical Refineries are a combination of

highly integrated processes involving Reaction, Separation; and Extraction

· Aromatics Complex- A combination of Process units that converts Naphtha and Pygas into basic chemical intermediates. Simplest configuration produces Benzene, Toluene and Xylene.

· Basic Building Block Chemicals. · Process Flow Configuration· Hands-on Session - Constructing simplified flow-schemes· Major Processes: Separation, Reaction, Equipment and

Environment· The Petrochem business? · Role of Engineers· Challenges in the Chemical Industry· Where can I get more information· Workshop Summary & Questions