Manufacture of L-cystine

PROJECT REPORT

on

MANUFACTURE OF L-CYSTINE

Submitted in partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGY in

CHEMICAL ENGINEERING by

DIVYA PRABHU (10704006) DHEERAJ.T.S (10704023)

under the guidance of

Ms.K.SOFIYA, M.TECH., (Lecturer, School of Chemical Engineering)

FACULTY OF ENGINEERING AND TECHNOLOGY

SRM UNIVERSITY (under section 3 of UGC Act,1956)

SRM Nagar, Kattankulathur – 603 203 Kancheepuram Dist.

MAY 2008

BONAFIDE CERTIFICATE

Certified that this project report “MANUFACTURE OF L-CYSTINE SUGAR”

is the bonafide work of DIVYA PRABHU (10704006), DHEERAJ.T.S (10704021)

who carried out the project work under my supervision.

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HEAD OF THE DEPARTMENT INTERNAL GUIDE Date: EXTERNAL EXAMINER INTERNAL EXAMINER Date :

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ACKNOWLEDGEMENT

ACKNOWLEDGEMENT

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We take this opportunity to thank the Associate Director Dr. C..Muthamizhchelvan for

providing us with an excellent infrastructure and conducive atmosphere for developing

our project.

We would also like to thank the Head of Department of Chemical engineering

Dr.R.Karthikeyan, for encouraging us to do our project.

We sincerely thank our project guide Ms.K.Sofiya for her valuable guidance, support

and encouragement in all aspects of this project and for its completion

We would also like to thank our faculty members and technicians of our Chemical

Department who helped in the successful completion of our project.

TABLE OF CONTENTS

S.NO CHAPTER PAGE NO.

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1. ABSTRACT 6

2. INTRODUCTION 8

3. PROPERTIES 12

4. APPLICATIONS OF L-CYSTINE 15

5. PROCESS DESCRIPTION 17

6. MATERIAL BALANCE 22

7. ENERGY BALANCE 33

8. DESIGN 43

9. COST ESTIMATION 55

10. PLANT LAYOUT AND LOCATION 61

11. SAFETY AND LOSS PREVENTION 69

12. MATERIALS OF CONSTRUCTION 72

13. INSTRUMENTATION AND CONTROL 75

14. CONCLUSION 79

15. NOMENCLATURE 81

16. BIBLIOGRAPHY 84

LIST OF TABLES

TABLE PAGE NO.

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6.1 Glass-Lined Reactor 24

6.2 Neutralization Tank 1 25

6.3 Filter Press 1 26

6.4 Decolorization Tank 1 26




6.8 Decolorization Tank 3 29


6.10 Final Neutralization Tank 31

6.11 Centrifuge 32

6.12 Tray Dryer 32

7.1 Glass Lined Reactor 35



7.4 Final Neutralization Tank 41

7.5 Tray Dryer 42

LIST OF FIGURES FIGURE PAGE NO.

5.1 Flow sheet for the manufacture 18

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of L-Cystine From human hair

8.1 Design of Reactor Vessel 48

8.2 Design of Filter Press 51

8.3 Design of Storage Vessel 54

10.1 Plant Layout 68

12.1 Glass Lined Equipment 73

12.2 Neutralization Tank 74

12.3 Decolorization Tank 74

13.1 Control Scheme 78

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ABSTRACT

ABSTRACT

The amino-acid L-cystine is manufactured from human hair. Human hair is rich in two

basic amino acid compounds such as L-cystine and L-Tyrosine, with L-Cystine

comprising about 12% of the hair.

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Chemically hair is a biopolymer largely of cystine cross linked proteins termed

keratins. L-cystine is a hydrolytic product of human hair, wool, horn, nail, feathers. But

human hair is considered to be the cheapest source and it has the major content of L-

Cystine than any other sources.

The human hair is hydrolyzed by hydrochloric acid; the hydrolysate consists of L-

Cystine which is separated by repeated neutralization and filtration. pH maintenance is

important in this process to obtain the crystals of L-Cystine.

L-cystine is used as a food additives, flavor enhancer, nutrient supplement and dough

strengthener.

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INTRODUCTION

INTRODUCTION

2.1 L-CYSTINE L-Cystine is a non-essential amino acid which can be produced by human beings. It is

present in many proteins and is a major constituent of keratin, the principal protein of

hair, skin and wool. Cystine is known as a disulfide amino-acid because it consists of two

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cysteine segments with their respective sulfur atoms bonded firmly together. Cystine

plays a special role as a cross-linking agent in protein structure.

2.2 NOTABLE FEATURES L-Cystine is found in the form of plates and prisms. It has a bland taste and can be taken

in powder or capsule form. The powder is water soluble. L-Cystine is the stable oxidized

form of L-Cysteine. L-refers to levorotatory, a type of optical rotation of a compound

under plane polarized light.

2.3 FUNCTIONS OF L-CYSTINE 1. It is necessary for the formation of skin and accelerates healing after injury or surgery.

2. L-Cystine strengthens the immune system, reduces damage from free radicals.

3. It promotes leucocyte formation and helps in the assimilation of vitamin B6.

4. This amino-acid is an integral part of the insulin molecule and thus important in

glucose metabolism.

5. Its sulfur rich amino group has been found useful in soothing for a variety of skin

conditions.

6. Allows skin to appear smooth and supple instead of rough and patchy.

7. It functions as an anti-oxidant and is a powerful aid to the body in protecting against

pollution and radiation.

8. It can help slow down the aging process and neutralize toxins. It serves to spare

Methanione.

2.4 HISTORY AND ISOLATION FROM NATURAL SOURCES In 1810 Watlaston described an organic compound which he had isolated from urinary

stones; it was soluble in both acids and alkalis, and it separated from alkaline solution on

acidification with acetic acid in the form of hexagonal plates. He called it an oxide

because of its apparently amphoteric nature and since it was derived from material

accumulating in the bladder, he decided on the term “cystic oxide”. The compound was

analyzed by Thaulow in Leibig’s laboratory and yielded results from which correct

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formula C6H12N2O4S2 was deduced. The name cystine instead of cystic acid was

introduced by Berrelius in 1833. In 1899 Morner isolated it from a horn hydrolysate.

Mauthner was the first to measure the optical rotation of L-Cystine and reported in 1882

an (x)D value at 20° of -205.88° in HCl solution.

2.5 SELECTION OF RAW MATERIAL The amino acid L-Cystine is produced from many sources like wool, horn, nail, feathers,

horse hair and human hair. Among these sources human hair is preferable as its

adequately available and cheap. Human hair consists of 12% of L-Cystine, 2.6% L-

Tyrosine, 82.4% of other amino acids, water, lipids, pigments and trace elements. In the

acid hydrolysis extraction process only barbed hair is suitable. Lengthy hair create

problem in the cleaning process. Dyed hair is also not preferable.

2.6 HAIR CHEMISTRY 2.6.1 HUMAN HAIR DESCRIPTION

Human hair is a keratin containing appendage that grows from large cavities or sacs

called follicles. The human hair fiber can be divided into three distinct zones along its

axis.The zone of biological synthesis and orientation resides at and around the bulb of the

hair. The next zone is the zone of keratinisation which is present in the outward direction

along the hair shaft, where stability is built into the hair structure via the formation of

cystine linkages, the third zone that eventually emerges through the skin surface is the

region of the permanent hair fibre which consists of dehydrated cornified cuticle, cortical

and sometimes medullary cells and inter-cellular cement. The diameter of human hair

fibres varies from 15 to 100µm.

2.6.2 COMPONENTS OF THE HUMAN HAIR

Hair is a complex tissue consisting of several morphological components and each

component consists of several chemical species. Depending on its moisture content (up to

32% by weight) human hair consists of approximately 65% to 95% proteins. Its

remaining constituents are water, lipids, pigment and trace elements. Proteins are

condensation polymer of amino acids, and those amino acids are Glycine, Alanine,

Valine, Isoleucine, Leucine, Phenylalanine, Tyrosine, lysine, Arginine, Histidine,

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Citrulline, Aspartic acid, Glutamic acid, Threonine, Serine, Cystine, Methionine,

Cysteine, Cysteic acid, Proline and Typtophan.

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PROPERTIES

PROPERTIES

3.1 GENERAL CHARACTERISTICS Crystal stem – Hexagonal system

Specific rotation – [α]²°D = -200 °~ -225° (1N HCl, C=2)

Melting point – 260°C

Stability – Decomposes in hot alkaline

aqueous solution

Solubility – H2O g/dl 0.0110(25°)

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0.0239(50°)

0.0523(70°)

0.1140(100°)

3.2 PHYSICAL & CHEMICAL PROPERTIES Physical state – powder

Appearance – white crystals

Specific gravity – 1.677

pH – 5.0~6.5

State of solution – ≥98%

Molecular weight – 240.31

EMPIRICAL FORMULA

C6H12N2O4S2

C= 29.99% H2= 5.03% O2= 26.63% N2= 11.66% S=26.69%

3.3 STRUCTURE –OOC–CH–CH2–S–S–CH2–CH–COO–

NH3+ NH3+

3.4 METABOLISM Glycogenic L-Cystine undergoes a reciprocal conversation with L-Cystine in the

oxidation reduction metabolism. It is metabolized to form pyruvic acid. L-Cystine is not

essential for human as it is derived from L-Methanione.

L-Cystine (1) is reduced to form L-Cysteine (2).

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3.5 ANALYTICAL REACTIONS A large number of gravimetric, colorimetric and titrimetric procedures have been offered

for the determination of cystine either as such or after its conversion to cysteine.

Such procedures depend in part upon

a) The ability of the disulfide grouping of cystine to undergo

disproportionate cleavage with heavy metals and with certain chemical reagents.

b) The kind of oxidation reduction reactions in which the sulfahydryl function of

cysteine can participate.

c) The property to form colored conjugates with various reagents and hence can

be estimated by colorimetric or spectrophotometric means; titration of the

sulfahydryl group may be achieved through the application of iodometric,

acidimetric and electrometric methods.

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APPLICATIONS

APPLICATIONS

The demand for L-cystine is 3000 tpa.

The applications of L-Cystine in different fields are:

4.1 PHARMACEUTICALS

• Expectorant for respiratory diseases such as chronic bronchitis.

• As a nutrients (transfusion solution) before and after operation on patients having

Hypoproteinemia and Hypo alimentation

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4.2 FOOD

• Components in flavors.

• Meat and meat products.

• Baby foods.

• Milk and milk products.

• Dough conditioner.

4.3 OTHERS

• Used to manufacture L-Taurine and L-glutathione .

Taurine plays a key role in central nervous system function. Glutathione is

critical for immune system function.

• Cystine strengthens the protective lining of the stomach and intestines.

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PROCESS DESCRIPTION

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PROCESS DESCRIPTION Acid- hydrolysis extraction method is a batch process. Total batch time is 10.5 hrs. Hence

there are two batches in a day.

5.1 RAW MATERIAL PREPARATION Hair is the raw material used in the manufacture of L-cystine. Hair is first cleaned

manually, removing unwanted contents such as matches, paper, hair pins and cigarette

butts. The other principal contamination is sand which causes trouble and is removed by

beater, then hair is sent for screening and the sand particles are screened out. Then hair is

immersed in a container of hot water where it is totally rid of all impurities including oil.

5.2 GLASS-LINED REACTOR The reaction is carried out in a Glass-lined reactor which is a jacketed vessel. HCl is used

for the hydrolysis of human hair. The temperature of the hydrolysis process should be

105°C to 110°C. Acid and water are added to the reactor initially followed by preheating

which is done by indirect steam heating. Hair is charged and temp. is maintained at

110°C. Hair is hydrolyzed into hydrolysate by the breaking up of the peptide bonds in the

hair. The amino-acids present in the hair separates from the pigments, lipids which are

the constituents of hair and forms a hydrolysate. The reactor consists of an agitator,

which agitates the charged hair and accelerates the conversion of solid hair into

hydrolysate. The hydrolysate liquid is pumped to the Neutralization tank 1.

5.3 NEUTRALISATION TANK 1 In the Neutralization tank 1 the acidic condition is neutralized by adding Sodium

carbonate. The hydrolysate consists of 21 amino-acids, other impurities, acid is cooled to

50°C by water cooling. The pH is maintained at 5.2. From the hydrolysate the amino-acid

L-cystine precipitates down due to the pH maintenance. The reaction that takes place in

the tank by the addition of soda ash is as follows.

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

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CO2 formed is emitted out and the neutralized solution with salt formed is pumped to

the filter press 1 for the filtration process.

5.4 FILTER PRESS 1 The black cake and other amino-acids are separated by filtration process. The black cake

consists of L-cystine, salt formed, and certain amount of impurities. The filtration

solution is the mother liquor of other amino-acids like glycine, alanine, valine, lysine,

tyrosine, cysteine etc. The black cake consists of some traces of other amino acids which

are removed in further process. The black cake is then sent to the decolourisation process.

5.5 DECOLOURISATION TANK 1 This decolourisation tank consists of HCl and the black cake is dropped into the tank and

agitation is done to dissolve the cake. Then activated carbon is further added to the

dissolved cake for decolourisation process. The black cake is decolourised to form a

brown acidified solution of L-Cystine.

5.6 FILTER PRESS 2 Activated carbon is separated in the filtration stage. The carbon separated is considered to

be waste cake, which should be properly discarded. The filtrate solution is brown in color

which is sent to the Neutralization tank 2 to neutralize the acidified solution.

5.7 NEUTRALIZATION TANK 2 The brown color solution is pumped inside the neutralization tank 2 which consist of

Sodium hydroxide. The acidic solution is neutralized and the pH is maintained at 1.8. The

salt is formed by the following reaction

2HCl + NaOH → NaCl + H2O

The L-cystine in the solution precipitates down due to pH maintenance.

5.8 FILTER PRESS 3 The neutralized solution is filtered to remove impurities. The solution is pumped to filter

press 3 to remove the water and separate the brown colored cake. The water removed in

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this filtration stage is sent to the Effluent Treatment Plant. The brown colored L-cystine

obtained is to be further decolorized to give white colored final product.

5.9 DECOLORIZATION TANK 2 The brown colored cake is washed off from filter press 3 and dropped into the

decolorization tank 2 which consists of HCl. The cake is dissolved in the acid by

agitation, and then activated carbon is added to decolorize the brown cake. The carbon

added adsorbs impurities present in the dissolved cake.

5.10 FILTER PRESS 4 The decolorized solution is acidic in nature and it consists of carbon. The carbon content

is separated at this filtration stage. The decolorized solution is obtained as a filtrate

solution and is sent to the final neutralization tank.

5.11 FINAL NEUTRALIZATION TANK The acidic solution is neutralized by adding NaOH, the pH is maintained at 2. The L-

cystine precipitates down. The salt is formed as follows,

HCl +NaOH → NaOH + H2O

The solution is then pumped to the centrifuge.

5.12 CENTRIFUGE The neutralized solution consists of excess water which is removed by the centrifugation

process. The centrifuge is top suspended type. The salt formed in the final neutralization

is removed in this stage. The decanted water consists of iron and traces of impurities.

5.13 TRAY DRYER The product obtained consists of moisture content to about 10% which is removed by the

tray dryer. The humidity is reduced by passing hot air at 120°C. The temperature of the

product is reduced by natural cooling. The dried product obtained is further blended and

packed.

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MATERIAL BALANCE

MATERIAL BALANCE

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Molecular weight: Hydrochloric Acid (HCl) = 36.46

Sodium Hydroxide (NaOH) = 40

Sodium Carbonate (Na2CO3) = 106

Water (H2O) = 18

Sodium Chloride (NaCl) = 58.46

Carbon di-oxide (CO2) = 44

Basis: 1000 Kg of human hair is taken as feed per batch.

Pure human hair is 80% of the feed = 800 kg

Impurities is 20% of the feed = 200 kg

6.1 GLASS LINED REACTOR Acid hydrolysis: 60% HCl is required

HCl required to hydrolyze 800 kg of human hair = 800 x 0.6

= 480 kg

H2O added to hydrolyze 800 kg of human hair = 800x 0.4

= 320 kg

2% of acid added is vaporized.

2% of water added is evaporated.

Hydrolysate H2O=313.6 kg HCl=470.4 kg Total Amino Acids=1000 kg

Human hair Pure content=800 kg Impurities=200 kg H2O=320 kg HCl=480 kg

GLASS LINED REACTOR

Evaporated Solution

Water =2% of 320 =6.4 kg HCl =2% of 480

=9.6 kg

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Output (kg)

Components

Input (kg)

Evaporated

Acid

Hydrolysate

Human Hair 800

Water 320 6.4 313.6

HCl 480 9.6 470.4

Impurities 200

Total amino acids 1000.0

16.0

1800 1800

6.2 NEUTRALIZATION TANK 1 Reaction:

2HCl + NaCO3 → 2NaCl+CO2+H2O

Amount of HCl required = (470.4x2)/36.46 = 25.8036 moles

Amount of Na2CO3 required = 25.8036 x 106/2 = 1367.5908 kg

Amount of NaCl formed =25.8036 x 58.46 = 1508.4785 kg

Amount of CO2 formed =25.8036 x 44/2 =567.6792 kg

Amount of H2O formed =25.8036 x 18/ 2 =232.2324 kg

76.6587% of NaCO3 solution is required to neutralize the hydrolysate.

Water required in neutralization =1784 x (1-0.766587) = 416.4092 kg

CO2 formed is emitted out =567.6792 kg

Amino acids contain 12% cystine.

CO2=567.6792 kg

Cystine=120 kg NaCl=1508.4785kg H2O=416.4092 +232.2324+313.6 =962.2416 kg Other amino Acids=409.6007 kg

Total amino acids=1000kg H2O=313.6kg HCl=470.4 kg

NEUTRALIZATION TANK 1

Water=416.4092 kg Na2CO3=1367.5908

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Output (kg) Components Input

(kg) Evaporated

Gas

Neutralized

Solution

HCl 470.4000

H2O 730.0092 962.2416

Na2CO3 1367.5908

Total amino acids 1000.0000

Cystine 120.0000

Other amino acids 409.6007

NaCl 1508.4785

CO2 67.6792

3568.0000 3568.0000

6.3 FILTER PRESS 1 The efficiency of the filter press1 is 90%.

The cystine loss is 10%.

Black cake consists of 5% of NaCl, 10% of H2O from their weights in the feed and 2% of

other amino acids in the form of impurities.

Black cake Cystine=108 kg NaCl=75.4239kg H2O=96.2242kg Impurities=8.192kg

Cystine =120 kg FILTER PRESS 1

NaCl=1508.4785 kg Water=962.2416 kg Other amino Acids=409.6007 kg

Filtrate Cystine=10% of 120 =12 kg NaCl=5% of 1508.4785 =1433.0545 kg Water=10% of 962.2416 =866.0174 kg Other amino Acids =401.4087 kg

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Output (kg) Components

Input

(kg) Black cake Filtrate solution

NaCl 1508.4785 75.4239 1433.0545

H2O 962.2416 96.2242 866.0174

Cystine 120.0000 108.0000 12.0000

Impurities 8.1920

Other amino acids 409.6007 401.4087

287.8402 2712.4806

3000.3208 3000.3208

6.4 DECOLOURIZATION TANK1 10% HCl is required to dissolve cystine cake.

HCl required to dissolve 287.8402 kg of cystine cake =287.8402 x 0.1 = 28.7840 kg

Water required to dissolve 287.8402 kg of cystine cake =287.8402 x 0.9 = 259.0562 kg

7% of carbon is required to decolorize cystine cake.

Carbon required= 287.8402 x 0.07 = 20.1488 kg

HCl=28.7840 kg Water=259.0562 kg Carbon=20.1488 kg

DECOLORIZATION TANK 1

Cystine=108 kg NaCl=75.4239 kg Water=96.2242 kg Impurities=8.192kg

Cystine=108kg H2O=355.2804kg NaCl=75.4239kg HCl=28.7840kg Carbon=20.1488kg Impurities=8.192kg

Components Input (kg) Output (kg)

Cystine 108.0000 108.0000

NaCl 75.4239 75.4239

H2O 355.2804 355.2804

HCl 28.7840 28.7840

Carbon 20.1488 20.1488

Impurities 8.1920 8.1920

595.8291 595.8291

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6.5 FILTER PRESS 2 8% of cystine loss. 3% of NaCl loss. 3% of HCl loss.98% of carbon separated. 6% of

water loss. Waste cake consists of 80% of total impurities.

FILTER PRESS2

Waste cake

Cystine=108 kg H2O=355.2804 kg Imp. =8.192kg NaCl=75.4239 kg HCl=28.7840 kg Carbon=20.1488kg

Filtrate Cystine=99.36kg H2O=333.9636kg Imp. =1.6384kg NaCl=73.1612kg

Cystine=0.08 x108 =8.64 kg HCl=0.03 x28.7840 =0.8635 kg H2O=0.06 x355.2804 =21.3168 kg NaCl=0.03 x75.4239 =2.2627 kg Carbon=0.98 x20.1488 =19.7458 kg Imp. =0.8 x8.192kg =6.5536 kg

HCl=27.9205kg


(kg) Waste cake Filtrate

Cystine 108.0000 8.6400 99.3600

NaCl 75.4239 2.2627 73.1612

HO 355.2804 21.3168 333.9636

HCl 28.7840 0.8635 27.9205

Carbon 20.1488 19.7458 0.4030

Impurities 8.1920 6.5536 1.6384

59.3824 536.4467

595.8291 595.8291

6.6 NEUTRALIZATION TANK 2

NaOH + HCl → NaCl + H2O

Amount of HCl reacted = 27.9205/36.46 = 0.7657 moles

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Amount of NaOH required = 0.7657 x 40 = 30.6280 kg

5% NaOH solution is required.

Water required to neutralize 536.4467 kg of filtrate = 536.4467 x 0.95 = 509.6244 kg


Cystine 99.3600 99.3600

NaCl 73.1612 117.9271

H2O 843.5880 857.3706

HCl 27.9205

Carbon 0.4030 0.4030


NaOH 30.6289

1076.6991 1076.6991

6.7 FILTER PRESS 3 Loss of cystine is 10%. Brown cystine cake consists of 5% of NaCl. 5% of moisture.

50% loss of impurities.

NEUTRALIZATION TANK 2

Brown cake

Filtrate solution

Cystine=0.9x99.36 =89.4240 kg NaCl=0.05x117.9271 =5.8964 kg H2O=0.05x857.3706 =42.8685 kg Imp. =0.50x1.638 =0.8192 kg

Cystine=99.36 kg NaCl=117.9271 kg H2O=857.3706kg Carbon=0.403 kg Imp. =1.6384 kg

FILTER PRESS 3

Water=509.6244 kgNaOH=30.6280 kg

Cystine=9.936 kg H2O=814.5021 kg NaCl=112.0307 kgCarbon=0.403 kg Imp. =0.8192 kg

Cystine=99.36 kg HCl=27.9205 kg NaCl=73.1612 kg Carbon=0.403 kg Water=333.9636 kg Imp.=1.6384 kg

Cystine=99.36kg NaCl=73.1612 +44.7658 =117.9271kg H2O =333.9636 +509.6244+3.7826 =857.3706 kg Carbon= 0.403 kg Imp. = 1.6384 kg

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(kg) Filtrate Brown cake

NaCl 117.9271 112.0307 5.8964

H2O 857.3706 814.5021 42.8685

Cystine 99.3600 9.9360 89.4240

Carbon 0.4030 0.4030

Impurities 1.6384 0.8192 0.8192

937.691 139.0081

1076.6991 1076.6991

6.8 DECOLORIZATION TANK 2 20% of HCl is required to dissolve Brown cystine cake.

HCl required = 139.0081 x 0.2 = 27.8016 kg

H2O required = 80% of 139.0081 = 111.2065 kg

10% of carbon is required to decolorize Brown Cystine cake.

Carbon required = 139.0081 x 0.1 = 13.9008 kg


Cystine 89.4240 89.4240

NaCl 5.8964 5.8964

H2O 154.0750 154.0750

HCl 27.8016 27.8016


Carbon 13.9008 13.9008

291.9170 291.9170

DDEECCOOLLOORRIIZZAATTIIOONN TTAANNKK 22

Cystine =89.4240 kg NaCl=5.8964 kg Water=42.8685 kg Impurities=0.8192 kg

Cystine =89.4240kg

HCl=27.8016 kg Water=111.2065 kgCarbon=13.9008 kg

NaCl=5.8964 kg H2O=154.0750 kg HCl=27.8016 kg Imp. =0.8192 kg Carbon=13.9008 kg

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6.9 FILTER PRESS 4 Cystine loss-10%;NaCl loss-10%; HCl loss-5%

In waste cake: Impurities-5% from its weight in feed

Carbon-98% from its weight in feed.


(kg) Waste cake Filtrate

Cystine 89.4240 8.9424 80.4816

NaCl 5.8964 0.5896 5.3068

HCl 27.8016 1.3901 26.4115

Impurities 0.8192 0.0410 0.7782

H2O 154.0750 7.7038 146.3712

Carbon 13.9008 13.6228 0.2780

32.2897 259.6273

291.9170 291.9170

FILTER PRESS 4

Cystine =89.4240 kgNaCl=5.8964 kg Carbon=13.9008 kg H2O=154.0750 kg HCl=27.8016 kg Imp. =0.8192 kg

Waste cakeCystine=8.9424kg NaCl=0.5896 kg H2O=7.7038 kg HCl=1.3901 kg Imp. =0.0410 kg Carbon=13.6228kg

Cystine=80.4816kg Filtrate

NaCl=5.3068 kg H2O=146.3712 kg HCl=26.4115 kg Imp. =0.7782 kg Carbon=0.2780 kg

6.10 FINAL NEUTRALIZATION TANK

NaOH + HCl → NaCl + H2O

Amount of HCl required = 26.4115/36.46 = 0.7244 moles

Amount of NaOH required = 0.7244 x 40 = 28.9760 kg

10% NaOH solution is required to neutralize cystine solution.

H2O required to neutralize 259.6273 kg of cystine solution=259.6273 x0.9=233.6646 kg

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Amount of NaCl formed = 0.7244 x 40 = 28.9760 kg

Amount of H2O formed= 0.7244 x 18 =13.0392 kg


Cystine 80.4816 80.4816

NaOH 28.9760 28.9760

Water 380.0358 380.0358

HCl 26.4115 26.4115


Carbon 0.2780 0.2780

NaCl 5.3068 5.3068

522.2679 522.2679

FINAL NEUTRALIZATION

TANK

NaOH=28.9760 kgWater=233.6646 kg

Cystine=80.4816 kg NaCl=5.3068 kg Water=146.3712 kg HCl=26.4115 kg Impurities=0.7782 kg Carbon=0.2780 kg

Cystine=80.4816kgNaCl=47.6551kg H2O=393.075kg Imp. =0.7782 kg Carbon=0.2780kg

6.11 CENTRIFUGE 15% Cystine loss. Impurities are reduced to 50%. Carbon is completely removed.

98% water loss. 98% NaCl loss. Cystine cake

Decanted water

CENTRIFUGECystine=80.4816 kg NaCl=47.6551 kg Water=393.0750 kg Imp. =0.7782 kg Carbon=0.2780 kg

Cystine=68.4094kgNaCl=0.9531 kg Water=7.8615 kg Imp. =0.3891kg

Cystine=12.0722kgImp. =0.3891kg NaCl=46.7020kg Water=385.2135kgCarbon=0.2780kg

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(kg) Decanted water Cystine cake

Cystine 80.4816 12.0722 68.4094

Water 393.0750 385.2135 7.8615

NaCl 47.6551 46.7020 0.9531

Impurities 0.7782 0.3891 0.3891

Carbon 0.2780 0.2780

444.6548 77.6131

522.2679 522.2679

6.12 TRAY DRYER 98% of the total moisture is removed in this process.

Cystine=68.4094 kg

TRAY DRYERNaCl=0.9531 kg H2O=7.8615 kg Imp. =0.3891 kg

Cystine=68.4094 kgNaCl=0.9531 kg H2O=0.1572 kg Imp. =0.3891kg

H2O=7.7043kg Output (kg) Components Input

(kg) Water removed Cystine

Cystine 68.4094 68.4094

Water 7.8615 7.7043 0.1572

NaCl 0.9531 0.9531


7.7043

77.6131 77.6131

PRODUCT L-cystine = 68.4094 kg /batch = 136.8188 kg/day (Two batches in a day)

Thus, L-cystine produced in an yr (300 working days) = 41tpa

34

ENERGY BALANCE

ENERGY BALANCE

35

Reference temperature: 25 °C = 298.15 K

Room temperature = 30 °C =303.15 K

Heat of formation (ΔHf cal/kmol) Specific heat constant (CP cal/mol K)

Na2CO3 (s) = -269.46 x 10³ Na2CO3 (s) = 28.9

HCl (l) = -39.85 x 10³ HCl (l) = 6.7 + 0.00084T

NaOH (l) = -112.193 x 10³ NaOH (l) = 9.4373

NaCl (s) = -98.321 x 10³ NaCl (s) = 10.79 + 0.0042T

H2O (l) = -68.3164 x 10³ H2O (l) = 18

CO2 (g) = -94.052 x 10³ CO2 (g) = 10.34 + 0.00274T – 195500/T²

C (s) = 2.673 + 0.002617T – 116900/T²

H2O (g) = 8.22 + 0.00015T + 0.00000134 T²

7.1 GLASS LINED REACTOR 110°C

Hair + H2O + HCl Hydrolyzed hair

HEAT ASSOCIATED WITH REACTANTS

303.15

QHCL = 480 x 10³/36.46 ʃ (6.7 + 0.00084T) dT cal = 0.4576 x 10³ kcal

298.15

303.15

QH2O = 320 x 10³/18 ʃ (18) dT cal = 0.0889 x 10³ kcal

298.15

ΔQ reactant = 0.5465 x 10³ kcal

HEAT ASSOCIATED WITH PRODUCTS

383.15

QHCL = 470.4 x 10³/36.46 ʃ (6.7 + 0.00084T) dT cal = 7.6614 x 10³ kcal

298.15

383.15

QH2O = 313.6 x10³/18 ʃ (18) dT cal =26.656 x 10³ kcal

36

298.15

373.15

Evaporated acid: QH2O = 6.4 x10³ /18 ʃ (8.22+ 1.5xE-4 T + 1.34xE-6 T² ) dT

298.15

+ 6.4 x10³/18 x (9729) = 3.6838 x 10³ kcal

383.15

QHCL = 9.6 x10³/36.46 ʃ (6.7 + 0.00084T) dT + 9.6 x10³/18 x (3860)

298.15

= 1.1720 x 10³ kcal

ΔQ product = 39.1732 x 10³ kcal

CHANGE IN ENERGY

ΔQ required = ΔQ product – ΔQ reactant + ΔH° R

= 39.1732 – 0.5465 + 0 = 38.6267 x 10³ kcal

Components Input (kcal) x 10³ Output (kcal) x 10³

HCl 0.4576 7.6614

H2O(l) 0.0889 26.6560

H2O(g) 1.1720

Heat of reaction 0

Heat supplied 38.6267

39.1732 39.1732

7.2 NEUTRALIZATION TANK 1 50°C

Na2CO3 + 2HCl 2NaCl + CO2 + H2O

STANDARD HEAT OF REACTION AT 298.15K

ΔHR° = (ΔHf) product – (ΔHf) reactant

For 1mole of Na2CO3 :

ΔHR°= {[2(-98.321) + (-94.052) + (-68.3164)] – [(-269.46) + 2(-.85)]} x 10³

= – 9.8504 x 10³ kcal

37

For 1367.5908/106 moles of Na2CO3 :

ΔHR°= (- 9.8504 x 10³) x 1367.5908/106

= -127.0879 x 10³ kcal


383.15

QHCL = 470.4 x10³/36.46 ʃ (6.7 + 0.00084T) dT cal = 7.6614 x 10³ kcal

298.15

383.15

QH2O = 730.0092 x10³/18 ʃ (18) dT cal = 62.0508 x10³ kcal

298.15

303.15

QNa2CO3=1367.5908 x10³/106 ʃ (28.9) dT cal=18.6431 x10³ kcal

298.15

ΔQ reactant = 88.3553 x10³ kcal


323.15

QNaCl = 1508.4785 x10³ /58.46 ʃ (10.79 + 0.0042T) dT cal =7.8022 x10³ kcal

298.15

323.15

QH2O = 962.2416 x10³ /18 ʃ (18) dT cal = 24.056 x10³ kcal

298.15

323.15

Qcystine = 120 x10³ /240.31 ʃ (141.2) dT cal = 1.7627 x10³ kcal

298.15

323.15

QCO2=567.6792 x10³/44 ʃ (10.34+0.00274T–195500/T²)dT cal = 2.9552 x10³ kcal

298.15

38

ΔQ product = 36.5761 x10³ kcal

CHANGE IN ENERGY


= (36.5761 – 88.3553 – 127.0879) x10³= - 178.8671 x10³ kcal

Components Input (kcal) x10³ Output (kcal) x10³

HCl 7.6614

H2O(l) 62.0508 24.0560

Na2CO3 18.6431

NaCl 7.8022

Cystine 1.7627

CO2 2.9552

Heat of reaction 127.0879

Heat released 178.8671

215.4432 215.4432

7.3 NEUTRALIZATION TANK 2

50°C

NaOH + HCl NaCl + H2O



For 1mole of NaOH

ΔHR° = {[(-98.321) + (-68.3164)] – [(-112.193) + (-39.85)]} X10³ = – 14.5944 x10³ kcal

For 30.628/40 moles of NaOH

ΔHR° = (-14.5944 x10³) x 30.628/40 = -11.1749 x10³ kcal


303.15

Qcystine = 99.36 x10³/240.31 ʃ (141.2) dT cal = 0.2919x10³ kcal

39

298.15

303.15

QNaCl = 73.1612 x10³/58.46 ʃ (10.79 + 0.0042T) dT cal = 0.0754 x10³ kcal

298.15

303.15

QNaOH = 30.628 x10³ /40 ʃ (9.4373) dT cal = 0.0361 x10³ kcal

298.15

303.15

QHCL = 27.9205 x10³ /36.46 ʃ (6.7 + 0.00084T) dT cal = 0.0266 x10³ kcal

298.15

303.15


298.15

303.15

Qcarbon = 0.403 x10³/12 ʃ (2.673+0.002617T–116900/T²)dT cal = 0.0003 x10³ kcal

298.15



323.15

Qcystine = 99.36 x10³/240.31 ʃ (141.2)dT cal = 1.4595 x10³ kcal

298.15

323.15

QNaCl = 117.9271 x10³/58.46 ʃ (10.79 + 0.0042T) dT cal =0.6099 x10³kcal

298.15

323.15


298.15

40

323.15


298.15

ΔQ product = 23.5056 x10³kcal

CHANGE IN ENERGY


= (23.5056 – 4.6482 – 11.1749) x10³ = 7.6825 x10³ kcal

Components Input (kcal) x10³ Output(kcal) x10³

Cystine 0.2919 1.4595

NaCl 0.0754 0.6099

H2O 4.2179 21.4343

HCl 0.0266

Carbon 0.0003 0.0019

NaOH 0.0361



23.5056 23.5056

7.4 FINAL NEUTRALIZATION TANK 50°C

NaOH + HCl NaCl + H2O



For 1mole of NaOH:

ΔHR° = {[(-98.321) + (-68.3164)] – [(-112.193) + (-39.85)]} x10³= – 14.5944 x10³ kcal

For 28.976/40 moles of NaOH:

ΔHR°= (-14.5944 x10³) x 28.976/40 = -10.5722 x10³ kcal


303.15

Qcystine = 80.4816 x10³ /240.31 ʃ (141.2) dT cal = 0.2364 x10³ kcal

41

298.15

303.15

QNaCl = 5.3068 x10³ /58.46 ʃ (10.79 + 0.0042T) dT cal = 0.0055 x10³ kcal

298.15

303.15

QNaOH = 28.976 x10³ /40 ʃ (9.4373) dT cal = 0.0342 x10³ kcal

298.15

303.15

QHCL = 26.4115 x10³ /36.46 ʃ (6.7 + 0.00084T) dT cal = 0.0334 x10³ kcal

298.15

303.15

QH2O = 380.0358 x10³ /18 ʃ (18) dT cal = 1.9002 x10³ kcal

298.15

303.15

Qcarbon = 0.278 x10³ /12 ʃ (2.673+0.002617T–116900/T²)dT cal = 0.0002 x10³ kcal

298.15



323.15

Qcystine =80.4816x10³/240.31 ʃ (141.2) dT cal=1.1822 x10³kcal

298.15

323.15

QNaCl = 47.6551 x10³/58.46 ʃ (10.79 + 0.0042T) dT cal = 0.2464 x10³kcal

298.15

323.15


298.15

42

323.15


298.15


CHANGE IN ENERGY


= 11.2568 – 2.2099 – 10.5722 = -1.5253 x10³ kcal

Components Input(kcal) x10³ Output(kcal) x10³

Cystine 0.2364 1.1822

NaOH 0.0342

H2O 1.9002 9.8269

HCl 0.0334

Carbon 0.0002 0.0013

NaCl 0.0055 0.2464


Heat released 1.5253

12.7821 12.7821

7.5 TRAY DRYER HEAT ASSOCIATED WITH REACTANTS

303.15

Qcystine = 68.4094 x10³ /240.31 ʃ (141.2) dT cal = 0.2010 x10³ kcal

298.15

303.15

QNaCl = 0.9531 x10³ /58.46 ʃ (10.79 + 0.0042T) dT cal = 0.0001 x10³kcal

298.15

303.15


298.15

43

ΔQ reactant = 0.2404 x10³kcal


393.15

Qcystine = 68.4094 x10³/240.31 ʃ (141.2) dT cal =3.8186 x10³ kcal

298.15

393.15

QNaCl = 0.9531 x10³/58.46 ʃ (10.79 + 0.0042T)dT cal = 0.0189 x10³kcal

298.15

393.15

QH2O = 0.1572 x10³/18 ʃ (18) dT cal = 0.0149 x10³kcal

298.15 393.15

Evaporated water: QH2O = 7.7043 x10³/18 ʃ (8.22+ 1.5xE-4 T + 1.34xE-6 T² ) dT

298.15

+ 7.7043 x10³/18 x (9729) = 4.4345 x10³kcal


CHANGE IN ENERGY

ΔQ required = ΔH product – ΔH reactant = (8.2869 – 0.2404 ) x10³ = 8.0465 x10³kcal

Components Input(kcal) x10³ Output(kcal) x10³

Cystine 0.2010 3.8186

H2O(l) 0.0393 0.0149

NaCl 0.0001 0.0189

H2O(g) 4.5071


8.2869 8.2869

44

DESIGN

DESIGN

8.1 DESIGN OF REACTOR VESSEL Data:

Density of water = 1000kg/m³

45

Density of HCl = 84.3681 kg/m³

Density of Hair = 237 kg/m³

Amount of water = 320 kg

Amount of HCL = 480 kg

Amount of Hair = 800 kg

Volume of water = 320/1000 = 0.32 m³

Volume of HCL = 480/845.3681 = 0.5678 m³

Volume of Hair = 800/237 = 3.3755 m³

Total volume = 4.2633 m³

Let us take 10% excess volume

Working volume = 4.2633(1+0.1) = 4.6896 m³

Working volume = volume of cylindrical portion + Volume of conical portion

= {π x (Dt/2)² x Hcy} + {π /3x (Dt/2)² x Hconi}

Where, Dt – Diameter of Vessel (m)

Hcy – Height of Cylindrical Portion (m)

Hconi – Height of Conical portion (m)

Ht – Height of Reactor Vessel (m)

∴ {π x (Dt/2)² x Hcy} + {π /3x (Dt/2)² x Hconi} = 4.6896

Hcy = 2Dt & Hconi = Dt /2

{π x (Dt/2)² x 2Dt } + {π /3x (Dt/2)² x Dt /2} = 4.6896

π /2 x Dt³ + π /24 x Dt³ = 4.6896

13π /24 x Dt³ = 4.6896

Dt = 1.402 m

Hcy = 2Dt = 2.804 m

Hconi = Dt /2 = 0.701 m

Ht = Hcy + Hconi = 3.505 m

Thickness of cylindrical portion = pDt = ρgHcy x Dt = 7861.093 x 9.81x 2.804 x 1.402

2f 2fs 2x (5 x106)

46

= 0.0303 m = 3.03 cm

Thickness of lining = 20% of Thickness of cylindrical portion = 0.2 x 3.03 = 0.06 cm

Thickness of conical head = pDt/2f cosα = ρgHconi x Dt = 7861.093 x 9.81x 0.701x 1.402

2fs cosα 2x (9.8 x106) xcos45°

= 0.0055 m = 5.5 mm

Where, fs – Shear Stress (kg/cm²)

P – Pressure exerted (N/m²)

AGITATOR

Da =Diameter of Agitator = 1/3 Dt = 0.4673 m

Let us assume the speed of agitator ‘u’ as 350 rpm

π DaN = u

π x 0.4673 x N = 350

N = speed of motor = 238.4089 rpm = 3.9734 rps

Reynolds number

NRe = NDa²ρ/µ

ρ = density = 237 kg/m³

µ = viscosity = 6.002 x 10-4 kg/ms

NRe = 342614 > 104, thus turbulent region

From NRe vs. power number (Np) table : Np = 5

Power number

Np = P/( ρ x N³ x Da5)

P = Np x ρ x N³ x Da5 = 5 x 237 x (3.9734) ³ x (0.46735) = 1656.4721 watts

= 1.6565 kw = 2.2214 HP

25% excess power

P = 2.2214 (1+0.25) = 2.7768 HP

47

Shaft diameter

Tc = Torque = HP x 75 x 60/ 2π N = 2.7768 x 75 x 60 = 8.3417 Nm

2π x 238.4089

Tmax = c x Tc = 1.9 x 8.3417 = 15.8492 Nm

ZP = Polar Modulus of shaft = Tmax/fs = 15.8492/ (5 x 106) = 3.1698 x 10-6 m³

π ds³/16 = ZP

ds = 0.0253 m

Some standard ratios

Da/ Dt = 1/3

E/Dt = 1/3

L/Da = ¼

W/Da = 1/5

H/Dt = 1

J/Dt = 1/12

E = height of impellor above vessel floor = 0.4673 m

L = length of impellor blade = 0.1168 m

W = width of impellor = 0.0935 m

H =depth of liquid in vessel = 1.402 m

J = width of baffle = 0.1168 m

DESIGN SUMMARY

Diameter of Vessel (Dt) = 1.402 m

Height of Cylindrical Portion (Hcy) = 2.804 m

Height of Conical portion (Hconi) = 0.701 m

Height of Reactor Vessel (Ht) = 3.505 m

Thickness of cylindrical portion = 3.03 cm

48

Thickness of lining = 0.06 cm

Thickness of conical head = 0.55 cm

Diameter of Agitator (Da) =0.4673 m

Shaft diameter (ds) = 0.0253 m

Height of impellor above vessel floor (E) = 0.4673 m

Length of impellor blade (L) = 0.1168 m

Width of impellor (W) = 0.0935 m

Depth of liquid in vessel (H) = 1.402 m

Width of baffle (J) = 0.1168 m

49

FIGURE 8.1 REACTOR

8.2 DESIGN OF FILTER PRESS

50

Basis: Carbon – water slurry: 13.91kg of C /154.08 kg H2O = 0.09 kg of C /kg of H2O

Specific gravity of carbon = 1.8

Assumptions: A plate and frame filter with frame 0.3 m²

The press takes 120s to dismantle.

120s to reassemble.

120s to remove cake from each layer.

Pressure = 275 KN/ m² = 275 x 10³ N/m²

Cake porosity = ε = 0.5

Let ‘n’ be the no. of frames and ‘d’ thickness of frame.

Total time for one complete cycle = Tf + 120n +240 sec

Overall rate of filtration = Vf

Tf + 120n +240

For constant rate of filtration Vf ² = ΔP A² Tf / µ c α

Where, Vf = volume of filtrate (m³)

Tf = time for filtration (s)

ΔP= pressure difference = (275-101.3) x 10³ N/ m²

A = area = 2n x 0.09 = 0.18n m²

µ = viscosity = 10-3 kgm/s

c =mass of solid deposited on filter per unit volume of filtrate

=13.6228 = 93 kg/m³

(146.3712/1000)

α = specific cake resistance = 8.8 x 107 x [1+ 1.64 x 10³x (ΔP)0.86] m/kg

Vf = volume of frames = 0.3² nd = 0.9nd

Volume of cake per unit volume of filtrate 0.09/ (0.5x1.8)

Vf ² = ΔP A² Tf

µ c α

(0.9 nd) ² = (275-101.3) x 10³ x (0.18n) ² x Tf

93 x 10-3 x α

(0.9 nd) ² = 1.28 n² Tf x 10-5

51

Tf = 6.328 x 104 d²

Let us take overall rate of filtration as 1.25 x 10-4 m³/s

1.25 x 10-4 = Vf

Tf + 120n +240

1.25 x 10-4 = 0.9nd / (6.328 x 104 d² +120n + 240)

7.91d² + 0.0015 n + 0.03 = 0.9nd

n = (7.91d² + 0.03) / (0.9d - 0.0015)

To find minimum number of trays: dn/dd = 0

(0.9d - 0.0015) (15.82d) - (7.91d² + 0.03)0.9 = 0

14.238 d²– 0.0237d – 7.119 d² – 0.027 = 0

7.119 d²– 0.0237d – 0.027 = 0

d = 0.0633 m = 63.3 mm

n = (7.91d² + 0.03) / (0.9d - 0.0015) ~ 2

Tf = 253.56 sec

Time for one complete cycle = Tf + 120n +240 = 733.56 sec

Overall rate of filtration = 0.9 nd = 1.55 x 10-4 m³/s

Tf + 120n +240

DESIGN SUMMARY

Number of frames (n) = 2

Thickness of frame (d) = 63.3 mm

Time of filtration (Tf) = 253.56 s

Time for one cycle = 733.56 s

Overall rate of filtration = 1.55 x 10-4 m³/s

Pressure = 275 KN/m²

Area of filter (A) = 0.9 m²

52

FIGURE 8.2 FILTER PRESS

8.3 DESIGN OF STORAGE TANK

53

Basis: Storage for one month

Material construction – stainless steel

Data:

Density of stainless steel = 7700 kg/m³

Density of NaCl = 2160 kg/m³

Density of H2O = 1000 kg/m³

Density of cystine = 1671 kg/m³

Density of carbon = 1800 kg/m³

Amount of NaCl = 224.0651 kg

Amount of H2O = 1629.0068 kg

Amount of cystine = 19.872 kg

Amount of carbon = 0.806 kg

Volume of NaCl = 0.1037 m³

Volume of H2O = 1.629 m³

Volume of cystine = 0.0119 m³

Volume of carbon = 0.0005 m³

Total volume = 1.7451 m³

Average density = total mass/ total volume = 1073.72 kg/m³

Volume per batch = 1.7451 m³

2 batches per day volume per day = 3.5 m³

25 working days in a month volume per month = 87.5 m³

Assume H/D ratio as 0.5

Volume V = π /4 D²H

87.5 = π /4 D² (0.5 D)

87.5 = π /8 D3

D = 6.06 m

H = 0.5 D = 3.03 m

Giving 10% allowance

54

D = 6.06(1+0.1) = 6.666 m

H = 3.03(1+0.1) = 3.333 m

Pressure p = avg. density x g x H

= 1073.72 x 9.81 x 3.333

= 35107.133 N/m² = 35.1071 KN/m²

Design pressure p = 35.1071 (1+0.1) = 38.6178 kN/m²

As the diameter is less than 15m, assume minimum steel thickness as 5mm.

DESIGN SUMMARY

Diameter of tank (D) = 6.666 m

Height of tank (H) = 3.333 m

Design pressure (p) = 38.6178 kN/m²

Plate thickness = 5 mm

55

FIGURE 8.3 STORAGE TANK

A -Storage tank; B - solution; C - Sludge; D - Tank roof; E - Loading valve; F - Riser; G - Pump hose ; H - Bottom hose; J - Main valve.

56

COST ESTIMATION

COST ESTIMATION

Number of working days per year = 300

Cost of 1kg of L-Cystine = Rs 1,10,000

Production of L-Cystine = 136.8188 kg/day

Gross sales for 1 yr or total income =110000x136.8188x 300 = Rs 450,00,00,000

TURN OVER RATIO:

57

It can be defined as the ratio of total income to fixed capital investment.

Turn over ratio = Total Income

Fixed capital Investment

For chemical industries the turn over ratio is one.

Thus, Fixed capital investment = Gross Annual Sales = Rs 450,00,00,000

But, Fixed capital investment = Direct cost + Indirect cost

DIRECT COST: It is taken as 70% of the fixed capital investment= 0.7 x 4500000000 = Rs 3,37,50,00,000

The costs involved in the direct cost are,

i. Equipment cost

ii. Installation & Painting cost

iii. Instrumentation Cost

iv. Electrical cost

v. Piping Cost

vi. Building, process and auxiliary cost

vii. Service facilities & yard improvement cost

viii. Land cost

Equipment cost

It is taken as 24% of fixed capital investment = 0.24 x 4500000000 = Rs 108,00,00,000

Painting and installation cost

It is taken as 40% of the equipment cost = 0.4 x 1080000000 = Rs 43,20,00,000

Instrumentation cost

It can be taken as 10% of equipment cost = 0.1 x 1080000000 = Rs 10,80,00,000

58

Piping cost

It is 25% of the equipment cost = 0.25 x 108000000 = Rs 27,00,00,000

Electrical cost


Building, process and auxiliary cost

It is 39.1677% of equipment cost = 0.391677 x 108000000 = Rs 42,30,00,400

Service facilities & yard improvement cost


Land cost

It is usually taken as 1% of fixed capital cost = 0.01 x 4500000000 = Rs 4,50,00,000

INDIRECT COST:

Indirect cost = Fixed Capital Investment – Direct Cost

= 4500000000 – 3375000000 = Rs 1,12,50,00,000

It consists of the following items

i. Engineering and supervision cost

ii. Contingency

iii. Working capital

Engineering and supervision cost


Contingency

It can be taken as 3.7% of fixed capital = 0.037 x 4500000000 = Rs 16,65,00,000

Working capital

It is 20% of total capital investment

Total capital investment = fixed capital + working capital

59

= 4500000000 + (0.2 x 4500000000) = Rs 5,40,00,00,000

Working capital = 0.2 x 5400000000 = Rs 1,08,00,00,000

Estimation of total product cost

Annual income = Rs 45,00,00,00,00

Gross earning is 10% of annual income = 0.1 x 4500000000 = Rs 45,00,00,000

Product cost = Total annual income – Gross earnings

= 4500000000 – 450000000 = Rs 4,05,00,00,000

Direct production cost

It can be taken as 60% of the total product cost = 0.6 x 4050000000 = Rs 2,43,00,00,000

Raw materials cost

It is 2% of the total product cost = 0.02 x 4050000000 = Rs 8,10,00,000

Operating labor cost

It can be taken as 15% of total product cost = 0.15 x 4050000000 = Rs 60,75,00,000

Direct supervisory & clinical labor cost

It is 20% of operating labor cost = 0.2 x 607500000 = Rs 12,15,00,000

Utilities

It can be taken as 15% of total product cost = 0.15 x 4050000000 = Rs 60,75,00,000

Maintenance & repair cost

It is 3.6% of fixed capital investment cost = 0.036 x 4500000000 = Rs 16,20,00,000

Laboratory charges

It is taken as 6.67% of operating labor cost = 0.0667 x 607500000 = Rs 4,05,20,300

60

Royalties

It is taken as 1.45% of the fixed capital cost = 0.0145 x 4500000000 = Rs 6,52,50,000

Fixed charges

It can be taken as 20% of product cost = 0.2 x 4050000000 = Rs 81,00,00,000

Plant overheads

This includes cost for general upkeep and overhead packaging, medical services, safety

and protection, recreation, sewage, laboratories, and storage facilities.


Depreciation

Depreciation for machinery is 10% of fixed capital cost

= 0.1 x 4500000000 = Rs 45,00,00,000

Depreciation of building is 3% of the land cost

= 0.03 x 45000000 = Rs 13,50,000

Total depreciation value = 4500000000 – 1350000 = Rs 44,86,50,000

Insurance

It is 1% of the fixed capital cost = 0.01 x 4500000000 = Rs 45000000

Rent value

It is 3.033% of the total product cost = 0.03033 x 4050000000 = Rs 12,28,36,500

General expenses

Administrative cost includes cost for officer, legal fees, office supplier and

communication.

It is 5% of the total; product cost = 0.05 x 4050000000 = Rs 20,25,00,000

Distribution and selling cost

61

It accounts for 7% of the total product cost = 0.07 x 4050000000 = Rs 28,35,00,000

Research and development cost

It is 1% of the total product cost = 0.01x 4050000000 = Rs 4,05,00,000

Financing


Net profit

It is obtained after deduction of taxes from the Gross Earnings.

Net profit is 40% of the Gross Earnings = 0.4 x 4500000000 = Rs 1,80,00,00,000

Determination of Pay-Back period (without interest charges)

= Depreciable fixed capital investment

(Average profit + average depreciation)/yr

= 4500000000

(1800000000 + 450000000)

= 2 yrs.

62

PLANT LAYOUT

AND

LOCATION

PLANT LAYOUT AND LOCATION

A suitable site must be found for a new project, and the site and equipment layout

planned.

10.1 PLANT LOCATION AND SITE SELECTION The geographical location of the final plant can have strong influence on the success of

the industrial venture. Considerable care must be exercised in selecting the plant site, and

many different factors must be considered. The location of the plant can also have a

crucial effect on the profitability of a project.

The choice of the final site should first be based on a complete survey of the

advantages and disadvantages of various geographical areas and ultimately, on the

advantages and disadvantages of the available real estate. The various principal factors

63

that must be considered while selecting a suitable plant site are briefly discussed in this

section. The factors to be considered are:

1. Raw material availability.

2. Location, with respect to the marketing area.

3. Availability of suitable land.

4. Transport facilities.

5. Availability of labors.

6. Availability of utilities (Water, Electricity).

7. Environmental impact and effluent disposal.

8. Local community considerations.

9. Climate.

10. Political strategic considerations.

11. Taxations and legal restrictions

10.1.1 RAW MATERIALS AVAILABILITY:

The source of raw materials is one of the most important factors influencing the selection

of a plant site. Attention should be given to the purchased price of the raw materials,

distance from the source of supply, freight and transportation expenses, availability and

reliability of supply, purity of raw materials and storage requirements.

10.1.2 LOCATION:

The location of markets or intermediate distribution centers affects the cost of product

distribution and time required for shipping. Proximity to the major markets is an

important consideration in the selection of the plant site, because the buyer usually finds

advantageous to purchase from near-by sources.

10.1.3 AVAILABILITY OF SUITABLE LAND:

The characteristics of the land at the proposed plant site should be examined carefully.

The topography of the tract of land structure must be considered, since either or both may

have a pronounced effect on the construction costs. The cost of the land is important, as

well as local building costs and living conditions. Future changes may make it desirable

or necessary to expand the plant facilities.

64

10.1.4 TRANSPORT

The transport of materials and products to and from plant will be an overriding

consideration in site selection. If practicable, a site should be selected so that it is close to

at least two major forms of transport: road, rail, waterway or a seaport. Road transport is

being increasingly used, and is suitable for local distribution from a central warehouse.

Rail transport will be cheaper for the long-distance transport. If possible the plant site

should have access to all three types of transportation.

10.1.5 AVAILABILITY OF LABORS:

Labors will be needed for construction of the plant and its operation. Skilled construction

workers will usually be brought in from outside the site, but there should be an adequate

pool of unskilled labors available locally; and labors suitable for training to operate the

plant. Skilled tradesmen will be needed for plant maintenance.

10.1.6 AVAILABILITY OF UTILITIES:

The word “utilities” is generally used for the ancillary services needed in the operation of

any production process. These services will normally be supplied from a central facility

and includes Water, Fuel and Electricity which are briefly described as follows:

Water: -

The water is required for large industrial as well as general purposes, starting with water

for cooling, washing, steam generation and as a raw material. The plant therefore must be

located where a dependable water supply is available namely lakes, rivers, wells, seas. If

the water supply shows seasonal fluctuations, it’s desirable to construct a reservoir or to

drill several standby wells

Electricity: -

Power and steam requirements are high in most industrial plants and fuel is ordinarily

required to supply these utilities. Power, fuel and steam are required for running the

various equipments like generators, motors, turbines, plant lightings and general use and

thus be considered as one major factor is choice of plant site.

65

10.1.7 ENVIRONMENTAL IMPACT AND EFFLUENT DISPOSAL:

Facilities must be provided for the effective disposal of the effluent without any public

nuisance. In choosing a plant site, the permissible tolerance levels for various effluents

should be considered and attention should be given to potential requirements for

additional waste treatment facilities. The disposal of toxic and harmful effluents will be

covered by local regulations, and the appropriate authorities must be consulted during the

initial site survey to determine the standards that must be met

10.1.8 LOCAL COMMUNITY CONSIDERATIONS:

The proposed plant must fit in with and be acceptable to the local community. Full

consideration must be given to the safe location of the plant so that it does not impose a

significant additional risk to the community.

10.1.9 CLIMATE:

Adverse climatic conditions at site will increase costs. Extremes of low temperatures will

require the provision of additional insulation and special heating for equipment and

piping. Similarly, excessive humidity and hot temperatures pose serious problems and

must be considered for selecting a site for the plant. Stronger structures will be needed at

locations subject to high wind loads or earthquakes.

10.1.10 POLITICAL AND STRATEGIC CONSIDERATIONS

Capital grants, tax concessions, and other inducements are often given by governments to

direct new investment to preferred locations; such as areas of high unemployment. The

availability of such grants can be the overriding consideration in site selection.

10.1.11 TAXATION AND LEGAL RESTRICTIONS:

State and local tax rates on property income, unemployment insurance, and similar items

vary from one location to another. Similarly, local regulations on zoning, building codes,

nuisance aspects and others facilities can have a major influence on the final choice of the

plant site.

10.2 THE SITE LAYOUT

66

The process units and ancillary buildings should be laid out to give the most economical

flow of materials and personnel around the site. Hazardous processes must be located at a

safe distance from other buildings. Consideration must also be given to the future

expansion of the site. The ancillary buildings and services required on a site, in addition

to the main processing units will include:

1. Raw material and Product Storage.

2. Maintenance Workshop.

3. Stores for maintenance and operating supplies.

4. Laboratories for process control.

5. Fire Station and other emergency services.

6. Utilities: steam boilers, compressed air, power generation, refrigeration, transformers.

7. Effluent disposal plant.

8. Offices for general administration.

9. Canteens and other amenity buildings, such as medical Centre.

10. Car parks.

10.3 PLANT LAY OUT After the flow process diagrams are completed and before detailed piping, structural and

electrical design can begin, the layout of process units in a plant and the equipment

within these process unit must be planned. This layout can play an important part in

determining construction and manufacturing costs, and thus must be planned carefully

with attention being given to future problems that may arise.

Thus the economic construction and efficient operation of a process unit will depend on

how well the plant and equipment specified on the process flow sheet is laid out. The

principal factors that are considered are listed below:

1. Economic considerations: construction and operating costs.

2. Process requirements.

3. Convenience of operation.

4. Convenience of maintenance.

5. Health and Safety considerations.

6. Future plant expansion.

67

7. Modular construction.

10.3.1 COSTS:

The coat of construction can be minimized by adopting a layout that gives the shortest

run of connecting pipe between equipment, and least amount of structural steel work.

However, this will not necessarily be the best arrangement.

10.3.2 PROCESS REQUIREMENTS:

An example of the need to take into account process consideration is the need to elevate

the base of columns to provide the necessary net positive suction head to a pump.

10.3.3 CONVENIENCE OF OPERATION:

Equipment that needs to have frequent attention should be located convenient to the

control room. Valves, sample points, and instruments should be located at convenient

positions and heights. Sufficient working space and headroom must be provided

10.3.4 CONVENIENCE OF MAINTENANCE:

Heat exchangers need to be sited so that the tube bundles can be easily withdrawn for

cleaning and tube replacement. Vessels that require frequent replacement of catalyst or

packing should be located on the out side of buildings. Equipment that requires

dismantling for maintenance, such as compressors and large pumps, should be places

under cover.

10.3.5 HEALTH AND SAFETY CONSIDERATIONS:

Blast walls may be needed to isolate potentially hazardous equipment, and confine the

effects of an explosion. At least two escape routes for operators must be provided from

each level in process buildings.

10.3.6 FUTURE PLANT EXPANSION:

68

Equipment should be located so that it can be conveniently tied in with any future

expansion of the process. Space should be left on pipe alleys for future needs, and service

pipes over-sized to allow for future requirements.

10.3.7 MODULAR CONSTRUCTION:

In recent years there has been a move to assemble sections of plant at the plant

manufacturer’s site. These modules will include the equipment, structural steel, piping

and instrumentation. The modules are then transported to the plant site, by road or sea.

The advantages of modular construction are:

1. Improved quality control.

2. Reduced construction cost.

3. Less need for skilled labors on site.

The disadvantages of modular construction are:

1. Higher design costs & more structural steel work.

2. More flanged constructions & possible problems with assembly, on site.

69

FIGURE 10.1 SITE LAYOUT

70

SAFETY

AND

LOSS PREVENTION

SAFETY AND LOSS PREVENTION

Any organization has a legal and moral obligation to safeguard the health and welfare of

its employees and the general public.

Safety and loss prevention in process design can be considered under the following broad

headings.

71

• Identification and assessment of hazards.

• Control of the hazards; for example, by containment of flammable and toxic

materials.

• Control of the process.

Process can be divided into those that are intrinsically safe and those for which the safety

has to be engineered in. an intrinsically safe process is one in which safe operation is

inherent in the nature of the process.

The designer should always select a process that is inherently safe whenever it is practical

and economical. The process that we are employing to manufacture l-cystine is inherently

safe. However in most chemical manufacturing processes, dangerous situations can

develop if the process conditions deviate from the design values.

Some of the process hazards are listed.

1. Toxic materials

2. Dust explosion.

3. low temperature

4. Flammable materials

5. Corrosion and erosion

6. Leakage joints and packing

PREVENTIVE AND PROTECTIVE MEASURES The basic safety and fire protective measures that should be included in all chemical

process designs are listed below.

1. Adequate and secure water supplies for fire fighting.

2. Correct structural design of vessels, piping and steel work.

3. Pressure relief devices.

4. Earthing of electrical equipments.

5. Adequate separation of hazardous equipments.

6. Safe design and location of control rooms.

PREVENTIVE MEASURES - CATEGORIES

72

1. Those that reduce the number of incidents such as, sound mechanical design of

equipment and piping, operating and maintenance procedures and operator

training.

2. Those that reduce the scale of a potential incident such as, measures for fire

protection and fixed fire fighting equipments.

The other common safety measures followed in the process industry are:

1. Compulsory wearing of helmets.

2. Wearing goggles while working in the furnace, any other fired equipment.

3. Wearing gloves while handling chemicals.

4. Wearing leather shoes in order to protect the legs from heavy materials.

73

MATERIALS

OF

CONSTRUCTION

MATERIALS OF CONSTRUCTION

The most important characteristics to be considered when selecting a material of

construction are:

1. Mechanical properties.

(a) Strength – tensile strength

(b) Stiffness – elastic modulus (young’s modulus)

(c) Toughness – fracture resistance

(d) Hardness – wear resistance

(e) Fatigue and creep resistance

2. The effect of high and low temperatures on the mechanical properties.

3. Corrosion resistance.

74

4. Any special properties required such as, thermal conductivity, electrical

resistance, magnetic properties.

5. Ease of fabrication – forming, welding, casting.

6. Availability in standard sizes – plates, sections, tubes.

7. Cost.

12.1 REACTOR The reactor is a glass-lined equipment. Its main body is made of high quality carbon steel

lined with special silicate glass by firing them at high temperature. The glass-lined

equipment, therefore, has high mechanical features and corrosion resistance

12.2 NEUTRALIZATION TANK Neutralization tank is cylindrical and have bolted down and gasketed covers. All

hardware for bolting are stainless steel, gaskets are neoprene.

75

12.3 DECOLORIZATION TANK Decolorization tank is cylindrical in shape. It is made up of stainless steel as it is fairly

corrosion resistant and has good mechanical properties.

INSTRUMENTATION

76

AND CONTROL

INSTRUMENTATION AND CONTROL

The process flow sheet shows the arrangement of the major equipments and thus, the

control of such major equipments is necessary.

13.1 INSTRUMENTS Instruments are provided to monitor the key process variable during plant operation.

They may be incorporated in automatic control loops, or used for the manual monitoring

of the process operation. 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.

13.2 OBJECTIVES

13.2.1 SAFE PLANT OPERATION

77

1) To keep the process variables within known safe limits.

2) To detect dangerous situations as they develop and to provide alarms and automatic

shut down systems.

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

13.2.2 PRODUCTION RATE

To achieve the design product output.

13.2.3 PRODUCT QUALITY

To maintain the product composition within the specified quality standards.

13.2.4 COST

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

13.3 TYPICAL CONTROL SYSTEMS 13.3.1 LEVEL CONTROL

In any equipment where an interface exists between two phases (liquid-vapor), some

means of maintaining the interface at the required level must be provided. The control

valve should be placed on the discharge line from the pump.

In this process, a level control valve is used in the reactor, neutralization tanks and

Decolorization tanks.

13.3.2 PRESSURE CONTROL

Pressure control will be necessary for most systems

handling vapor or gas. The method of control will depend on the nature of the process.

13.3.3 FLOW CONTROL

Flow control is usually associated with inventory control in a storage tank or other

equipment. There must be a reservoir to take up the changes in flow rate. To provide flow

control on a compressor or pump running at a fixed speed and supplying a next constant

78

volume output, a by-pass would be used. Flow control valves are used in the reactors,

neutralization tanks and Decolorization tanks to control the flow of input and output

streams.

13.3.4 CASCADE CONTROL

With this arrangement, output of one controller is used to adjust the set point of another.

Cascade control can give smoother control in situations where direct control of the

variable would lead to unstable operation. In reactor and neutralization tank 1

temperature control is cascaded with flow controls.

13.3.5 REACTOR CONTROL

The schemes used for reactor control depend on the process and the type of the reactor. If

a reliable on-line analyzer is available, and the reactor dynamics are suitable, the product

composition can be monitored continuously and the reactor conditions and feed flows

controlled automatically to maintain the desired product composition and yield. More

often, the operator is the final link in the control loop, adjusting the controller set points

to maintain the product within specification, based on periodic laboratory analyses.

Reactor temperature will normally be controlled by regulating the flow of the heating or

cooling medium. Pressure is held constant. Material balance control will be necessary to

maintain the correct flow of reactants, products and unreacted materials.

79

LC

FC

FC

TC

FC

FIGURE 13.1 STIRRED TANK REACTOR CONTROL SCHEME, Temperature: cascade control, and Reagent: flow control

80

CONCLUSION

CONCLUSION

In this project the dominant route for the manufacture of L-Cystine from Human Hair is

discussed. The process is an acid hydrolysis extraction process and is done in batch

operation. The yield obtained is 98% pure. This chapter provides a brief idea about the

material and energy balance calculations, design of a reactor vessel, the layout of the

plant and the pay back period in cost estimation. This process consists of raw materials of

low cost and finally yields a product of commercially high cost.

81

82

NOMENCLATURE

NOMENCLATURE

A – Area of filter (m²)

CP – Specific Heat Constant (cal/mol K)

c – Mass of solid deposited on filter per unit volume of filtrate

ds – Diameter of shaft (m)

Dt – Diameter of Vessel (m)

Da – Diameter of Agitator (m)

d – Thickness of frame (m)

D – Diameter of storage tank (m)

E – Height of Agitator above vessel floor (m)

fs – Shear Stress (kg/cm²)

g – Gravitational acceleration (m/s²)

ΔHf – Heat of Formation (kcal/mol)

H – Height of storage tank (m)

Hcy – Height of Cylindrical Portion (m)

83

Hconi – Height of Conical portion (m)

Ht – Height of Reactor Vessel (m)

ΔH°R – Heat of reaction (kcal/mole)

H – Depth of liquid in Vessel (m)

J – Width of Baffle (m)

L – Length of Blade (m)

L – Length of Agitator Blade (m)

Np – Power number

N – Rotational speed of Motor (rpm)

NRe – Reynolds number

n – Number of Frames in filter press

P – Power requirement for motor (Watts)

ΔP – Pressure difference (N/m²)

p – Design pressure for storage tank (N/m²)

Q – Heat required (kcal)

T – Thickness of Vessel (m)

Tc – Torque (Nm)

Tmax – Maximum Torque (Nm)

Tf – Time for filtration (s)

U – Speed of Agitator (rpm)

Vf – Volume of filtrate (m³)

W – Width of Blade (m)

Zp – Polar Modulus of shaft

Greek letters:

µ – Viscosity (kg/ms)

ρ – Density (kg/m³)

α – specific cake resistance (m/kg)

ε – Cake porosity

84

BIBLIOGRAPHY

85

BIBLIOGRAPHY

Douglas D. Schoon , John Halal

“Hair Structure & Chemistry”

Milady Publishing Company 1993

David Mautner Himmelblau

“Basic principles & Calculations in chemical engineering”

Prentice Hall PTR Publications 1996

Robert H Perry, Don W Green & James O Maloney

“Chemical Engineers Hand Book”

Mc Graw Hill Publications 1999

John Metcalfe Coulson, John Francis Richardson

“Plant Design & Economics for Chemical Engineers”

Butterworth and Heinemann Publications 2002

Warren L. McCabe, Julian C. Smith, Peter Harriot

“Unit Operations of Chemical Engineering”


Robert Ewald Treybal

“Mass Transfer operations’


M V Joshi, V V Mahajani

“Process Equipment Design”

Mac Millan Publications 2003

Max S Peters & Klaus D. Timmerhaus

“Plant Design & Economics for Chemical Engineers”


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Documents

Manufacture of L-cystine