VIT U N I V E R S I T Y

(Estd. u/s 3 of UGC Act 1956)

VELLORE – 632 014

SCHOOL OF MECHANICAL AND BUILDING SCIENCES

CHEMICAL ENGINEERING DIVISION

DESIGN PROJECT ON

ETHYLENE OXIDE

By:-

ROHIT KUMAR(10BCH0046)SHREY KULSHRESHTHA(10BCH0054)

SAMBHAV JOHARI(10BCH0071)

VII SemesterB. Tech. Mechanical Engg. Spec. in Chemical Processes

Design Project Record2012

VIT U N I V E R S I T Y

(Estd. u/s 3 of UGC Act 1956)

VELLORE – 632 014

SCHOOL OF MECHANICAL AND BUILDING SCIENCES

CHEMICAL ENGINEERING DIVISION

Certified that this is the bonafide record of work done by

1.ABHISHEK RANJAN(09BCH001)

2.ARSHI SAHU(09BCH017)

3.MANISH JAIN(09BCH032)

Of Seventh Semester students of B.Tech Mechanical Engineering with Specialization in

Chemical Processes during the year 2012.

Project guideProf. K Rambabu

Ackno w ledgement

We would like to express our deep gratitude to all those who gave us the possibility to complete this design project. We want to thank the Department of Chemical Engineering of VIT University, Vellore for helping us to commence on this design project. We have furthermore to thank the faculties Prof. David K Daniel, Prof. L.Muruganandam, Prof. Anand Gurumoorthy and Prof. Byron Smith who reviewed us periodically and encouraged us to go ahead with the work.

We are deeply indebted to our guide Prof. Rambabu K. who helped us in stimulating suggestions and helped and supported us with all the valuable hints.

Last but not least we wish to avail ourselves of this opportunity, express a sense of gratitude and love to our friends and beloved parents for their manual support, strength, help and for everything.

Preface

This design project includes various aspects of a chemical product development right from the market condition evaluation to the estimation of cost of the plant setup.

Chapter 1 deals with the introduction to the product (acetic acid) – its properties both physical and chemical. It also provides the application of acetic acid in various other areas such as manufacture of pharmaceuticals, etc.

Chapter 2 contains a study of acetic acid in the global as well as Indian market. The gap between demand and supply is studied and used to set a bar for the production rate for the plant.

Chapter 3 has a brief explanation of various available processes for the manufacture of the acetic acid. A comparison is also done between the chosen of the process and the other available processes. The detailed process description is also given for the selected process.

Chapter 4 includes material balance over all the equipments used in the plant for a production of 100 TPD of acetic acid. Both component-wise and overall mass flow rate has been provided. The mol%, and wt.% is also provided for each component and the molar flow rate of each is included too.

Chapter 5 contains enthalpy balance for all the streams in the plant in and out of each equipment. The utilities requirement are also calculated, stating the amount of cooling water and steam required for daily running of the plant.

Chapter 6 contains internal as well as external mechanical design. The number of stages is calculated using McCabe Thiele Method, and then the column design is done along with the plate specifications and then design of skirt support is also done.

Chapter 7 provides a cost estimation for the distillation column and also the overall plant cost. The total income and profit is also calculated along with the break even point for the plant.

Process flow sheet is also provided at the end along with the material safety data sheet.

TABLE OF CONTENTS

Certificate i

Acknowledgement ii

Preface iii

1. Introduction 1

2. Market Analysis 5

3. Process Selection 9

4. Material Balance 14

5. Energy Balance 17

6. Equipment Design 23

7. Cost Estimation 39

Reference

Process Flow Sheet

MSDS Sheets

Cha pter 1

I ntro ductio n

1.1 Basic P r o p er ti e s:

Acetic acid has a place in the organic chemical industry that is comparable to sulphuric acid in the inorganic chemical industry. The most commonly known acetic acid is also known as methane carboxylic acid. Its IUPAC name is ethanoic acid. Its molecular formula is CH3COOH and abbreviated as ACOH, with molecular weight of 60.05.

A clear, colorless liquid that has a piercingly sharp, pungent (vinegary odour) and is a dangerous vesicant. As the acid of vinegar, acetic acid is as ld as fermented liquors, which sour spontaneously and which are historically recorded prior to 3000BC.

It occurs both free and combined in the form of esters of various alcohols in many plants and has also been detected in animal secretions.

The term “acetic acid” have been introduced by Libavius (1540-1600AD), and the properties of icy (glacial) acetic acid and common vinegar were recognized. Many (attempts have been made to prepare icy acetic acid from repeated distillation of vinegar during these early studies), but it was normally prepared by dry distillation of copper acetate or similar heavy metals acetates like the production of sulphuric acid from its metallic salts. Later, Lavoisier believed acetic acid made by dry distillation of salts can be distinguished from acetic acid, the hypothetical acid of vinegar. After his death, the identity of acetic and acetous acid was demonstrated by Adet and others. But, final proof was obtained, when Kolbe first prepared acetic acid in 1847.

Today, acetic acid is one of the most important industrial organic acids. It is produced mostly synthetically in volume exceeding a billion pounds per year.

1.2 Phys ical Prop erties:

S .No. P r o p er ti e s Val u e 1 Molar Mass 60.05 g mol-1

2 Appearance Colourless Liquid3 Solubility in water Miscible4 Melting point 16.635 ± .002 oC5 Boiling Point 118oC6 Vapor pressure log p =7.55716– 1642.54/(233.386+1)7 Thermal conductivity 0.158 W/mK at 20ºC8 Heat of melting 207.1 J/g9 Heat of vaporization 394.5 J/g at boiling point10 Specific heat of vapor 5.029 J/gK at 124ºC11 Density, 20.0ºC 1.04928 g/ml12 Refractive index, nd 1.36965

13 Specific heat of solid0.837 J/gK at 100K11.83 mPa.s or cp at 20ºC10.97 mPa.s or cp at 25ºC

14 Critical pressure 57.856 kPa (571.1 atm)15 Critical temperature 321.6ºC

1

16Magnetic susceptibilitySolidLiquid

32.05 x 10-6 cm3/mol31.80 x 10-6 cm3/mol

17Dielectric constantSolidLiquid

2.665 at -10.0ºC6.710 at 20.0ºC

18surface tension,mN/m or dyne/cm

27.57 at 20.1ºC

19 Flash point, open cup 57ºC20 Autoignition point 465ºC21 Lower limit of flammability 40ºC22 Lower limit of flammability 5.4 vol % at 100ºC23 Acidity(pKa) 4.7624 Basicity(pKb) 9.198

25 Std. Enthalpy of formation ∆fH298 -483.88 - -483.16 kJ mol-1

26 Std. Enthalpy of combustion ∆cH298 -875.5- -874.82 kJ mol-1

27 Std. molar entropy So298 158.0 JK-1mol-1

28 Sp. Heat Capacity 123.1 JK-1mol-1

Though the molecular weight of acetic acid is 60.05, its apparent molecular weight varies with both temperature and the other associating substances present.

It is miscible in all proportions with water, ethanol and ether. It is an excellent solvent for organic compounds. A zero dipole moment for unsymmetrical acetic acid structure (is explained

by the formation of symmetric dimmers via hydrogen bonding in which the dipole moments cancel).

No high dissociation ionic species in acetic acid solution. Possesses relatively low basicity or proton affinity. Has a very strong leveling effect on bases and solvolyzes all strong bases

to acetate ion, CH3COO-.

1.3 Che mical Prop er ties:

Acidity

The hydrogen center in the carboxyl group (−COOH) in carboxylic acids such as acetic acidcan separate from the molecule by ionization:

CH3CO2H → CH3CO2- + H+

Reactions with Organic Compounds

2

Acetic acid undergoes the typical chemical reactions of a carboxylic acid. Upon treatment with a standard base, it converts to metal acetate and water. With strong bases (e.g., organolithium reagents), it can be doubly deprotonated to give LiCH2CO2Li. Reduction of acetic acid gives ethanol

Reactions with inorganic compounds

Acetic acid is mildly corrosive to metals including iron, magnesium, and zinc, forming hydrogen gas and salts called acetates:

Mg + 2 CH3COOH → (CH3COO)2Mg + H2

Because aluminium forms a passivating acid-resistant film of aluminium oxide, aluminium tanks are used to transport acetic acid. Metal acetates can also be prepared from acetic acid and an appropriate base, as in the popular "baking soda + vinegar" reaction:

NaHCO3 + CH3COOH → CH3COONa + CO2 + H2O

1.4 App li cation s of Acetic Acid :

The various areas where acetic acid has its wide use are: Over 60% of acetic acid produced goes into polymers derived from either Vinyl acetate (vinyl esters) or cellulose (cellulose esters). Most of poly (vinyl acetate) is used in paints and coatings or used for Making poly (vinyl alcohol) and plastics. Also, cellulose acetate is used to produce acetate fibres. Acetic acid and acetate esters are used extensively as solvents and in organic

synthesis. In the production of white lead and chrome yellow pigments, it is used to Make lead available in a soluble form for further reaction to give basic lead carbonate

and lead chromate. Also used to provide the necessary acidity in the number of processes carried out in

an aqueous media. Used in the mordanting process and in dyeing of wool in textile industry. Used as a coagulant for rubber latex in manufacture of elastic thread, as a component

of photographic stopping and fixing baths and as a laundry sour. Also used in electroplating, engraving and in the processing of fish glue. Dilute acetic acid functions either or both as a preservative and flavouring agent in

food stuffs such as pickled vegetables, condiments, jellies and confectionery. RDX - the high explosive cyclotrimethylenetrinitramine is furnished on nitration of

hexamethylenetetramine with acetic acid. Also, lower alkyl esters such as methanol, ethanol, isopropanol and butanol are

widely used as solvents for lacquers and adhesives. Other esters form basis for synthetic flavors for perfumes and bornyl acetate in the

manufacture of synthetic camphor.

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Acetic acid is mainly utilized in the manufacture of the following products:1. Acetic Anhydride: Acetic Anhydride is a very versatile product. It is a part of the

manufacturing of Cellulose Acetate fiber, Plastics, Vinyl Acetate Monomer etc. The pharmaceutical industry uses Acetic Anhydride as a dehydration agent. The Dye industry also uses it for manufacturing Dyes and Dye intermediates. Ordinance factories use it in the manufacture of explosives. Perfumes are also made by the use of Acetic Anhydride. Aspirin, Paracetamol and other antibiotics are also made by using Acetic Anhydride.

2. Vinyl Acetate: Vinyl Acetate is a basic raw material for Poly Vinyl Acetate and Poly Vinyl Alcohol. Vinyl Acetate Monomer is used in the manufacture of latex paint, paper coatings, Adhesives and textile finishing.

3. Cellulose Acetate: Cellulose Acetate is an important constituent of thermoplastics and fibers. The textile industry uses cellulose acetate widely for the production of cellulose acetate fiber. The other uses of Cellulose Acetate are the production of film, plastic sheets and the formulation of liquor.

4. Monochloro Acetic acid: Monochloro Acetic acid [MCA] is used extensively in the manufacture of Herbicides, Preservatives, Bacteriostat and Glycine. Mainly it is used in the manufacture of Carboxy Methyl Cellulose which is a gummy and strong adhesive powder used in drilling for oil. MCA is also used for producing laboratory chemicals like EDTA and 2 4 D Thioglucolic acid.

5. Purified Terepthalic Acid [PTA]: · Acetic acid finds use in the manufacture of PTA as a solvent. PTA is an alternative raw material for polyester fiber manufacture insteadof Dimethyl Terepthalate [DMT]

6. Food Additives[VINEGAR]: Acetic acid is widely used in the form of vinegar as a food additive. As vinegar it is used for the preservation of food and also to impart a sour taste to certain preparations.

4

Cha pter 2

Ma rket Analy sis

Chemicals are a part of every aspect of human life, right from the food we eat to the clothes we wear to the cars we drive. Chemical industry contributes significantly to improving the quality of life through breakthrough innovations enabling pure drinking water, faster medical treatment, stronger homes and greener fuels. The chemical industry is critical for the economic development of any country, providing products and enabling technical solutions in virtually all sectors of the economy.

Organic chemicals industry is one of the most significant sectors of the chemical industry. It plays a vital developmental role by providing chemicals and intermediates as inputs to other sectors of the industry like paints, adhesives, pharmaceuticals, dye stuffs and intermediates, leather chemicals, pesticides etc. Methanol, acetic acid, formaldehyde, pyridines, phenol, alkyl amines, ethyl acetate and acetic anhydride are the major organic chemicals produced in India. Formaldehyde and acetic acid are important methanol derivatives and are used in numerous industrial applications. Phenol is an aromatic compound and derived from cumene, benzene and propylene derivatives. Alkyl amines are used in the manufacture of surfactants. Pyridine derivatives are used in the manufacture of pharmaceuticals. Ethyl acetate is the ester of ethanol and acetic acid and is manufactured for use as a solvent. Acetic anhydride is widely used as a reagent. Natural gas/ naphtha are mainly used as feedstock for the manufacture of these organic chemicals. Alcohol is also an important feedstock for the industry, with sizable production of acetic acid and entire production of ethyl acetate being based on alcohol.

2.1 Gl ob al S cen ario:

A market study on glacial acetic acid discloses a large gap between its demand and supply. The production of acetic acid is sound globally but recent data shows a decreasing producing capacity of Asia worldwide. Most of Acetic Acid produced in Asia is consumed internally and the excess is being imported due to its cheapness in the process involved.

5

A comparison of the demand and supply chart from the 2008 data supports the fact. With the demand of 60%, Asian producers are able to supply only 57% of it. The rest of the demand is being imported from producers from other continents.

A study of world consumption of acetic acid in the year 2009 also reveals similar facts with china being the greatest consumer of acetic acid in the market and united states being the second most consumer.

In a recent study, total worldwide production of virgin acetic acid is estimated at 5 Mt/a (million metric tons per year), approximately half of which is produced in the United States. European production stands at approximately 1 Mt/a and is declining, and 0.7 Mt/a is produced in Japan. Another 1.5 Mt are recycled each year, bringing the total world marketto 6.5 Mt/a. The two biggest producers of virgin acetic acid are Celanese and BP

6

Chemicals. Other major producers include Millennium Chemicals, Sterling Chemicals, Samsung, Eastman, and Svensk Etanolkemi.

Of the total global acetic acid capacity (virgin acid), 44% is in China, followed by 21% for the rest of Asia, 19% in the United States and 6% in Western Europe. These regions make up90% of total world capacity.

2.2 Ind ian mark et:

With Asia’s growing contribution to the global chemical industry, India emerges as one of the focus destinations for chemical companies worldwide. With the current size of $108 billion1, the Indian chemical industry accounts for approximately 7% of Indian GDP. The chemicals sector accounts for about 14% in overall index of industrial production (IlP). Share of industry in national exports is around 11%. In terms of volume, India is the third-largest producer of chemicals in Asia, after China and Japan. Despite its large size and significant GDP contribution, India chemicals industry represents only around 3% of global chemicals.

Two distinct scenarios for the future of the Indian chemical industry emerge, based on how effectively the Indian industry leverages its strengths and manages challenges. In the base case scenario, with current initiatives of industry & government, the Indian chemical industry could grow at 11% p.a. to reach size of $224 billion by 2017. However, the industry could aspire to grow much more and its growth potential is limited only by its aspirations. In an optimistic scenario, high end–use demand based on increasing per capita consumption, improved export competitiveness and resultant growth impact for each sub-sector of the chemical industry could lead to an overall growth rate greater than 15% p.a. and a size of $290 billion by 2017.

During the XIth Five Year Plan period, production of major organic chemicals(including acetic acid) has shown a significant decline due to large volume imports taking place from countries like China, resulting in low operating ratios of ~ 60%.

The demand for organic chemicals in India has been increasing at nearly 6.5% during this period and has reached the level of 2.8 million tonnes. The domestic supply has however grown at a slower pace resulting in gradual widening of demand supply gap which was primarily bridged through imports. Domestic production declined at ~ 6% p.a. and imports grew at a rate of 17-19% p.a. during the XIth plan period.

Acetic Acid is primarily used for production of purified terephthalic acid (PTA), vinyl acetate monomer (VAM), acetic anhydride and acetate esters. In India, production of acetic acid is primarily based on alcohol and its demand has grown at 10% during XIth Five Year Plan period. At present the consumption is estimated to be 0.6 million tonnes which would reach nearly 1.0 million tonnes by end of XIIth Five Year Plan period (2012-2017). The demand growth is primarily driven by end use demand from PTA which is basic raw material for polyester and fiber. There is substantial incremental capacity of PTA, driving demand for acetic acid in this segment.

Acetic acid is primarily produced through alcohol or methanol route. Alcohol route in Indian context is gradually becoming unviable due to high prices and limited availability of this feedstock. At present bulk of acetic acid is imported with domestic production accounting for less than 30% of demand.Amongst the six major organic chemicals produced in India Acetic Acid contribute to nearly2/3rd of Indian basic organic chemical industry. The balance 1/3rd of the organic chemical consumption in the country is accounted for by other wide variety of chemicals.

7

A comparison of import and import volumes of acetic acid in the indian market shows the increasing import of acetic acid at a cheaper rate than the production cost used in indian market.

The above table shows a considerable increase in the import volumes of acetic acid (in metric tonnes) from the 7th five year plan. The import volume of 340.5 x 103 metric tonnes for the half of the 11th five year plan period is also comparatively larger than the volume of 389.7 x103 metric tonnes in the 10th five year plan. Moreover, the export volumes of acetic acid can also be seen decreasing from the table following the different five year plans. Cheap importhas led the chemical manufacturers to reduce their plant capacity utilization.

A bar chart of the demand and supply gap in the Indian market shows a constant existing gap. The global demand is also forecasted to reach 11.3 million tons by the year 2015 and hence a great scope for the establishment of a cost-effective process for acetic acid manufacture lies. In this design project we aim to cover the same gap by proposing a low cost process that is mainly used by the manufacturers outside India.

800000Demand And Supply Chart

700000

600000

500000

400000

300000

200000

100000

0 Production

Consumption

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Chap ter 3

Process S ele ction

The 99.8% pure acetic acid, sold in the name of glacial acetic acid can be manufactured by various processes. Each processes are discussed in detail in the following sections:

3.1 Variou s avail ab le Processes of S yn thesis of Acetic Acid :

a) By oxidation of Acetaldehyde:Oxidation of acetaldehyde with air or O2 to acetic acid takes place by a radical mechanism with peracetic acid as an intermediate. The acetyl radical, formed in the initiation step, reacts with O2 to make a peroxide radical which leads to the foris mation of peracetic acid. Although peracetic acid is formed by homolysis of the peroxy group, it is assumed that the peacetic acid preferentially reacts withacetaldehyde to give α-hydroethyl peracetate, which then decomposes through a cyclic transition state to two moles of acetic acid.If a redox catalyst is used for the oxidation of acetaldehyde to acetic acid, it not only serves to generate acetyl radicals initiating the oxidation but also accelerate the decomposition of peracetic acid. The resulting acetoxy causes chain branching. The usual catalysts used are solutions of Co and Mn acetates in low concentration (upto0.5 wt% of the reactant mixture).

2 CH3CHO + O2 → 2 CH3COOH

The mechanism of the process can be graphically represented as:

In Hoechst Process, the oxidation is usually done with oxygen, which operates continuously at 50-70oC in the oxidations towers of stainless steel (bubble columns) with acetic acid as solvent. Temperatures of atleast 50oC are necessary to achieve an adequate decomposition of peroxide and thus a sufficient rate of oxidation. The heat of reaction is removed by circulating the oxidation mixture through a cooling system. Careful temperature control limits the oxidative decomposition of acetic acid to formic acid, CO2, and small amounts of CO and H2O. Acetic acid selectivity reaches95-97% (based on CH,CHO).

9

Besides CO2 and formic acid, the byproducts include methyl acetate, methanol, methyl formate, and formaldehyde, which is separated by distillation.

b) By Oxidation of Alkanes and Alkenes: C, to C, hydrocarbons are the favoured feedstocks for the manufacture of acetic acid by oxidative degradation. They can be separated into the following groups and process modifications:1. n-Butane (Hoechst Celanese, Huls, UCC)Acetic acid can be prepared by uncatalyzed oxidation of n-Butane with oxygen in a

bubble column at 15-20 bar and 180oC using liquid oxidation products as reaction mixture. A wide range of by-products are formed including Acetaldehyde, acetone, methyl ketone, ethyl acetate, formic acid, propionic acid and butyric acid. Hence the conversion is limited in this process to 2% to prevent the formation of secondaryproducts (about 60% selectivity).

C4H10 + 5/2O2 2CH3COOH + H2O

2. n-Butenes (Bayer, with sec-butyl acetate as intermediate; Huls directly)

C4H8 + 2O2 2CH3COOH

In this process, n-Butene is oxidized at 200oC in a liquid phase consisting essentiallyof crude acetic acid. However the product acetic acid is very dilute and needs to be concentrated. The selectivity in this process reaches 73% at 75% conversion.

c) Anaerobic fermentation

Species of anaerobic bacteria Species of anaerobic bacteria, including members of the

genus Clos t rid i um or A ce tobact e rium can convert sugars to acetic acid directly,

without using ethanol as an intermediate. The overall chemical reaction conducted by

these bacteria may be represented as:

C6H12O6 → 3 CH3COOH

These acetogenic bacteria produce acetic acid from one-carbon compounds, including

methanol, carbon monoxide, or a mixture of carbon dioxide and hydrogen:

2 CO2 + 4 H2 → CH3COOH + 2 H2O

This ability of Clos t rid i um to utilize sugars directly, or to produce acetic acid from

less costly inputs, means that these bacteria could potentially produce acetic acid

more efficiently than ethanol-oxidizers like A ce tobact e r .

However, Clos t rid i um bacteria are less acid-tolerant than A ce tobac t e r . Even the

most acid-tolerant Clos t rid i um strains can produce vinegar of only a few per cent

acetic acid, compared to A ce t o ba c ter strains that can produce vinegar of up to 20%

acetic acid. At present,it remains more

cost-effective to produce vinegar using A ce tobact e r than to produce it

using Clos t rid i um and then concentrate it. As a result, although acetogenic bacteria

have been known since 1940, their industrial use

remains confined to a few niche applications.

10

d) Carbonylation of Methanol:The Carbonylation of methanol is mostly done in the presence of rhodium catalyst combined with iodine and is considered as an active catalyst system for the carbonylation. The reaction is as shown:

CH3OH + CO → CH3COOH

The process involves iodomethane as an intermediate, and occurs in three steps as shown

1. CH3OH + HI → CH3I + H2O

2. CH3I + CO → CH3COI

3. CH3COI + H2O → CH3COOH + HI

This process will be discussed in detail in the next section.

3.2 Th e S elected Proc es s (Cativa Proc ess) :

Production of Acetic Acid by carbonylation of methanol used to be done by a process named as Monsanto Process where Rhodium catalyst was used as an active catalyst with iodide of metals such as lithium. The process was carried at 50-60 bar pressure and at a temperature of150 to 200oC giving a high selectivity of 99% based on the methanol feed. But B.P chemicalscame up with a process named as Cativa that used Iridium catalyst with Hydrogen iodide as the active catalyst in the system. This overcame many limitations of the Monsanto process as

Lower water concentration was obtained in the product compared to Monsanto process.

The process now could be carried at a comparatively lesser pressure and temperature.

The number of distillation units was reduced. Iridium is cheaper than Rhodium, hence reducing the cost of production to a large

extent.

The cativa Process is carried 30-40 bar pressure and at a temperature of 150-180oC giving a high selectivity of 99% (based on the methanol feed). The reactions are:

Main reaction:

CH3OH + CO → CH3COOH ∆H= -138kJ/mol

Side Reactions:

CH3OH + CO C2H5COOH

CH3COOH + CH3OH CH3COOCH3

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3.3 Advan tages of select ed p rocess over o ther p rocesses :

The selected process has following advantages over other processes:

The selectivity of cativa process is 99% as compared to the 90% of acetaldehyde and even lesser in other processes.

The operation is cheaper than other processes. The methanol used as the feed is comparatively cheaper than the feed in other

processes. Fermentation process which also seems viable in terms of operation involves a

greater upstream and downstream cost for sterilisation of equipment to provide an environment for microbial growth.

The liquid phase reaction is easy to control.

3.4 Process D escrip tion :

The carbonylation process of methanol is carried out in a continuous stirred tank reactor. The methanol(stream 1) and carbon monoxide(stream 2) is fed to the reactor from the bottom as feed. The carbon monoxide is compressed in a compressor to 30 bar before inlet to the reactor to ensure the reaction is occurs in the liquid phase. The reaction is highly exothermic and hence a cooling jacket is provided outside the reactor to ensure that the proper

temperature of 150oC is maintained in the reactor. The initial heat required to ignite the reaction is mainly through passage of steam through the jacket. As the reaction starts, the heatof reaction is used to continue the reaction and excess heat is removed.

The unreacted gases are vented out through a scrubber (stream 7) which also works as a preheater for a part of methanol feed. A part of methanol feed (stream 3) is preheated from

ambient temperature to 60oC as it comes out of the scrubber (stream 5). Another work that is performed by the side stream is the stripping of entrained liquid in the vent gases and it also ensures that the loss of product with these gases is minimal. The vent gases generally exit the

scrubber at 50oC to the atmosphere.

The product stream from the CSTR, i.e. stream 6, rich in acetic acid and containing small concentrations of methanol, by-product propionic acid and water is made to pass through the throttling valve to the flash tank where the product is flashed to a reduced pressure of 1 atm. The product from the flash tank is fed to the light end distillation column at a temperature of52oC (stream 9). A recycle stream 8 is pumped from the bottom of the flash tank back to theCSTR.

In the light end distillation column the feed containing acetic acid, water, propionic acid, methanol and methyl acetate is distilled to separate light ends (methyl acetate and methanol) from the bottom stream 11 containing acetic acid, propionic acid and little concentration of water. The acetic acid is generally 87.6 % by wt. which is further purified in the acid purification unit to obtain the required product. The feed stream 9 enters at a temperature ofabout 52oC and the bottom stream leaves the end column at a temperature of 97oC.

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In the acid purification unit, the stream 11 enters at a temperature of 97oC. The higher boiling component propionic acid is obtained from the bottom of the distillation tower where a

temperature of 123oC is maintained. Glacial Acetic acid (99.8% by wt.) is obtained from the

top of the distillation tower, maintained at 118oC.

Enclosed: Process Flow Sheet of the Process.

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Cha pter 4

Ma teri al Ba la nce

From literature, selectivity to acetic acid(AA) = 99% (based on Methanol).Yield of Acetic Acid = 90%

Basis: 100 ton p er d ay of Gl acial Acetic Acid (produ ct)

It is known that 99.8% acetic acid by weight is to be obtained as the overhead product and the 93.5(wt %) propionic acid is obtained as bottom product with .09(wt%) of acetic acid in it and balance as water.

Hence, for 2nd Distil lation colum n (Aceti c A cid P urificati on Colum n)

We have, xD=0.998, xB=0.00085, xF=0.926 (all in wt%)and D= 100 TPD

= 4166.67 kg/hr of AA.

Taking wt. per hour basis of acetic acid,

B = D*(xF-xD)/(xB-xF)= 4166.67*(0.926-.998)/(0.00085-0.926)= 324.27 kg

Thus, F = D + B = 4490.94 kg.

Hence, the weight and wt. fraction can be arranged in the table as:

ComponentsFeed Bottom Overhead

wt% wt wt% wt wt% wt

H2O

CH3COOH

C2H5COOH

0.376 17.83576 1.636 9.502431 0.2 8.3333333

87.600 4158.828 0.08521 0.494943 99.8 4158.3333

12.024 570.8568 98.27885 570.8568

Total 100 4747.521 100 580.8542 100 4166.6667

And, for 1st Distil lation column ( Light End Dist il lation C olum n)

We have, xD=0.00839, xB=0.926, xF=0.915 (all in wt%)and B= 4490.94 kg

D= B*(xB-xF)/(xF-xD)= 4490.94*(0.926-0.915)/( 0.915-0.00839)= 53.139 kg

Thus, F= D + B = 4544.079 kg

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The weight and wt. fraction values can be arranged in the tabular column as:

ComponentsFeed Overhead Bottom

wt% wt wt% wt wt% Wt

CH3OH H2O

CH3COOH

CH3COOCH3

C2H5COOH

0.006 0.320521 0.217 0.430373

3.325 164.4556

84.127 4160.489 0.839 1.661085

11.390 563.2849 98.944 195.893

0.376 17.83576

87.600 4158.828

1.152 56.955 12.024 570.8568

Total 100 4945.505 100 197.9845 100 4747.521

Now, as assumed remaining methanol is converted to methyl acetate during the throttling operation. Hence the amount of acetic acid remains constant and can be used to find the moles(and thus the wt.)of methanol to be used.

Main Reactions:

Side Reactions:CH3OH + CO CH3COOH

CH3OH + ½ CO C2H5COOHCH3OH + CH3COOH CH3COOCH3

Ma teri al bal ance f or the di st ill at ion col umn,

Let the moles of methanol taken be x kmol.Also, yield = conversion * selectivity∴ we have conversion = 90.91%.

Taking mole balance on the reactor itself, we have:

CH3OH + CO CH3COOH

x kmoles + x kmoles 0.9091*x kmoles of AAof MeOH of CO

Unreacted MeOH = (1-.9091) * x = 0.0909 * x kmolesHence, this methanol is used in production of methyl acetate in the flash tank during the

throttling process. But it is known that we obtain 1000 ppm of methanol from the tank output. Thus,

Methanol consumed in flash tank = 0.0909 * x – 0.001 * x = 0.0899 * x kmoles

CH3OH + CH3COOH CH3COOCH3 + H2O

0.0899 * x kmoles of reactants 0.0899 * x kmoles of products

∴ total CH3COOH to light end distillation feed = 0.9091 * x – 0.0899 * x= 0.8192 * x kmoles

15

But, the kmoles of Acetic acid in the flash tank output = 69.28 kmolesHence, actual methanol requirement = 69.28/0.8192 = 84.57 kmoles

Also, total water is produced in propionic acid and methyl acetate reaction.

∴ Total water produced = 0.01* 0.9091 * 84.57 + 0.0899 * 84.57= 8.37 kmoles

Now, taking considerations of 0.5(wt. %) of water in methanol feed we have,∴ Total water in light end distillation column feed = 9.13 kmoles

Assuming carbon monoxide is taken 7.2% in excess than the methanol feed.∴ moles of carbon monoxide = 107.2% * 84.57 = 90.66 kmoles

Similarly, the moles of propionic acid and methyl acetate were also calculated and the value ispresented in the table below.

From the total moles, moles % = mole of component * 100/ total moles of mixture

From the mole %, wt % can be calculated as,wt. % of component i = (mole fraction of i * molar wt. of i)/total wt. of mixture.

Hence, obtaining any one values from %wt., wt. or mol. or mol.%, other values could be easily found out and the same is used to calculate the following table.

Thus from the calculations,

ComponentsCSTR Output Flash tank to DC-1 Feed

wt% wt kmol mol% wt% wt kmol mol%

CH3OH H2O

CH3COOH

CH3COOCH3

C2H5COOH

4.980 248.4213 7.69 8.85

0.555 27.69448 1.52 1.76

93.313 4654.45 76.88 88.51

1.151 57.41545 0.77 0.89

0.006 0.320521 0.01 0.01

3.325 164.4556 9.13 10.52

84.127 4160.489 69.28 79.82

11.390 563.2849 7.60 8.76

1.152 56.955 0.77 0.89

Total 100 4987.981 86.87 100.00 100 4945.505 86.79 100.00

Considering overall material balance assuming the reactor, scrubber and flash tank as a complete system we have,

Mass of gas in vent = mass of methanol in + mass of carbon monoxide in – mass of feed in light end distillation column∴ Mass of vent from scrubber = 2724.33 + 2539.43 – 4945.51= 318.25 kg

Also, 20% in excess promoter, i.e. Hydrogen Iodide and Iridium Catalyst is assumed to be used in thereactor. Hence, weight of catalyst = 20% excess of feed methanol

= 12981.36 kg = 12.98 tonnesThis catalyst is recycled back to the reactor and hence is not required to be fed again and again.

16

Ch a pter 5

Energ y Ba la nce

En thalp y Balan ce on S trea ms in an d ou t of th e Reacto r syste m:

F eed in (at a tempe ratur e of 30 oC ):

Total Enthalpy of stream 1 in = mass of methanol * Sp. Enthalpy of methanol + mass of water * Sp. Enthalpy of water

= 2710.71 * 7536.23 + 13.62 * 15856.6= 20644518.73 kJ/hr.

Total Enthalpy of stream 2 in = mass of CO * Sp. Enthalpy of CO= 2539.43 * 3941.28= 10008591.85 kJ/hr.

Total Enthalpy of recycle stream 7 in = ∑ mass of component i*Sp. Enthalpy ofcomponent i

The balance is shown in the following tabular column:

Components Enthalpy(kJ/kg) @ 30 b ar &150oC Kg/hr kJ/hr

Acetic Acid 7698.63 35.73 285207.11

Propionic Acid 6534.98 0.49 3340.79

Methanol 7072.02 0.00 20.75

Water 15349.07 1.41 22397.09

Total 42.48 339960.90∴ Total Enthalpy of feed in = 20644518.73 + 10008591.85 + 339960.90= 31004047.435 kJ/hr= 31004.047 MJ/hr

F eed out (at a tempe ratur e of 150 oC and 30 b ar):

Total Enthalpy of stream 6 in = ∑ mass of component I * Sp. Enthalpy of component i

Components Enthalpy(kJ/kg) @30 b ar &150oC Kg/hr kJ/hr

Acetic Acid 7698.63 4654.45 32575354.10

Propionic Acid 6534.98 57.42 341098.78

Methanol 7072.02 248.42 1597128.46

Water 15349.07 164.46 2294763.71

Total 5124.74 36808345.05

17

Total Enthalpy of Vent gases out of the scrubber = mass of gases * Sp. Enthalpy of gases= 318.25 * 3941.28= 1254311.25 kJ/hr

For the methanol side stream to the scrubber,Assuming the stream 5 (side stream from scrubber) is entering the reactor at a temperature of60oC and stream 8 (vent gases) is at a temperature of 50oC.Let the mass of methanol transferred to the side stream 3 by m kg.

∴ Heat gained by methanol stream 3 = Heat lost by gases stream 4∴ m * Sp. Enthalpy change of methanol stream = mass of vent gases * (Sp.

Enthalpy of gas at 150oC – Sp. Enthalpy of gas at 50oC)

∴ m = 318.25 * (3909.995 – 3816.51)/(7536.23-7430.636)= 281.74 kg

From literature, heat of reaction, ∆H = -138 kJ/mol = -138 x 103 kJ/kmol∴ Heat required by steam or coil to start the reaction = 138 x 103 * 76.88

(kmoles/hr ofacetic acid)

= 10609965.598 kJ/hrMaking overall Energy Balance on the reactor we have,

Energy in + Energy generated = Energy out + Energy Accumulated∴ Energy Accumulated = Energy in + Energy generated - Energy out

= 31004047.435 + 10609965.598 + 38062656.299= 3551356.734 kJ/hr

Assuming the cooling water is available from the cooling tower at 17oC and leaves the

reactor jacket at 80oC, this cooling water will be used to remove the extra heat accumulated in the reactor.∴ Heat gained by the cooling water = heat accumulated in the reactor

∴ Mass of cooling water required by the reactor = heat accumulated/(4.18*(80-17))

= 13485.823 kg/hr

18

En thalp y Balan ce ab out th e Ligh t En d Distill ation Colu mn :

Total Enthalpy of Feed stream 8 in = ∑ mass of component i*Sp. Enthalpy of component i

The balance is shown in the following tabular column:

F ee d str e a m 8:

Components Enthalpy(kJ/kg) @52 oC Kg/hr kJ/hrAcetic Acid 644.80 4160.49 2682673.08

Propionic Acid 692.89 56.95 39463.68Methanol 810.77 0.32 259.87

Methyl acetate 461.89 563.28 260176.10

Water 2211.05 164.46 363619.70

Total 4945.51 3346192.44

Similarly, the enthalpy balance for the overhead stream 9 and bottom stream 10 is written as:

Overhead stream 9:

Components Enthalpy(kJ/kg) @62 oC Kg/hr kJ/hrAcetic Acid 666.72 1.66 1107.47Methanol 838.35 0.43 360.81

Methyl Acetate 482.23 195.89 94465.13Total 197.98 95933.41

Bott om Stream 10:

Components Enthalpy(kJ/kg) @9 7 o C Kg/hr kJ/hrAcetic Acid 747.32 4158.83 3107962.08

Propionic Acid 796.32 570.86 454586.49Water 2399.71 17.84 42800.70Total 4747.52 3605349.27

Cooli ng W ater Requirement:

Amount of cooling water used by the condenser = mass of vapour being condensed * Sp. (assuming reflux ratio same Enthalpy / (Sp. Enthalpy change

as distillation column 2) of cooling water)∴ mass of cooling water required = 5.1 * 197.98 * 301.5 / (4.18 * (25-17))

= 908.91 kg

19

S team R equirement:

Taking overall energy balance over the distillation column we have,

Feed Enthalpy + Enthalpy of steam = Overhead Enthalpy + Bottom Enthalpy + HeatRemoved by Cooling Water∴ Total Enthalpy provided by steam = Overhead Enthalpy + Bottom Enthalpy + Heat

Removed by Cooling Water - Feed Enthalpy= 95933.41 + 3605349.27 + 304435.27 – 3346192.44= 659525.51 kJ/hr

Assuming 5% loss of energy from the column,Steam should provide energy = (1+5%) of 659525.51 kJ/hr

= 1.05 * 659525.51= 692501.786 kJ/hr

Now, assuming steam enters at 120oC and leaves as saturated liquid at 100oC we get, Mass of steam = Heat Required / Sp. Enthalpy change of steam

= 692501.786 / (1.9*(120-100))= 300.7 kg/hr

En thalp y Balan ce ab out th e Ac etic A cid Purif ication Colu mn :

Total Enthalpy of Feed stream 10 in = ∑ mass of component i*Sp. Enthalpy of component i

The balance is shown in the following tabular column:

F ee d str e a m 10:

Components Enthalpy(kJ/kg) @97oC Kg/hr kJ/hr

Acetic Acid 747.32 4158.83 3107962.08

Propionic Acid 796.32 570.86 454586.49

Water 2399.71 17.84 42800.70

Total 4747.52 3605349.27

Similarly, the enthalpy balance for the overhead stream 12 and bottom stream 11 is written as:Overhead stream 12:

Components Enthalpy(kJ/kmol) @118o C kmol/hr kJ/hrAcetic Acid 47980.18 69.24 3322358.33

Water 44131.17 0.46 20737.89

Total 69.71 3343096.21

20

Bott om Stream 10:

Components Enthalpy(kJ/kmol) @ 123 o C kmol/hr kJ/hr

Acetic Acid 48742.84 0.01 401.73

Propionic Acid 63883.93 7.71 492293.06Water 45214.04 0.53 23849.19Total 8.24 516543.98

Cooli ng W ater Requirement:

Amount of cooling water used by the condenser = mass of vapour being condensed * Sp. (assuming reflux ratio same Enthalpy / (Sp. Enthalpy change

as distillation column 2) of cooling water)∴ mass of cooling water required = 5.1 * 69.71 * 240.32 / (4.18 * (25-17))

= 2554.98 kg

S team R equirement:

Taking overall energy balance over the distillation column we have,

Feed Enthalpy + Enthalpy of steam = Overhead Enthalpy + Bottom Enthalpy + HeatRemoved by Cooling Water∴ Total Enthalpy provided by steam = Overhead Enthalpy + Bottom Enthalpy + Heat

Removed by Cooling Water - Feed Enthalpy= 3343096.21 + 516543.98 + 85438.50 - 3605349.27

= 339729.42 kJ/hr

Assuming 5% loss of energy from the column,Steam should provide energy = (1+5%) of 339729.42 kJ/hr

= 1.05 * 339729.42= 356715.891 kJ/hr

Now, assuming steam enters at 120oC and leaves as saturated liquid at 100oC we get, Mass of steam = Heat Required / Sp. Enthalpy change of steam

= 356715.891 / (1.9*(120-100))= 9387.26 kg/hr

Evalu atin g Total S team an d Coolin g w ater requ iremen t of Overall Plan t:

Total Cooling Water required = CW in reactor + CW in DC-1 + CW in DC-2= 13485.823 + 908.91 + 2554.98= 16949.713 kg/hr= 406.793 TPD

21

And, Total Steam Required = Steam in DC-1 + Steam in DC-2= 300.7 + 9387.26= 9687.96 kg/hr= 232.51 TPD

22

C h a pter 6

Equipment Des ig n

6.1 Numbe r of S tages Calculation (McCabe Th iele Me thod ):

From the material balance, we have

Feed to the distillation tower = 4158.828 kmol/ hr of acetic acid +17.83576 kmol / hr of water + 570.8568 kmol/ hr of propionic acid

= 4747.521 kmole/ hr

Top product from the distillation tower is 99.8 wt% acetic acid.Bottom product from the distillation tower is 98.288 wt% propionic acid .

Feed:Flow rate of feed = 4747.521 kmol/ hr.Mol fraction of acetic acid in feed = 4158.828 / 4747.521 = 0.8884Average molecular weight of feed = 60.91 kg/kmol

Distillate:Flow rate of distillate = 4166.6667 kmol/hrMol fraction of acetic acid = 0.99336Average molecular weight of distillate = 59.77 kg/kmol .

Residue:Flow rate of residue = 580.8542 kmol/hr. Mol fraction of acetic acid = 0.001Average molecular weight = 70.48 kg/kmol.

The feed to the distillation column is cold liquid at 97oC.

q= 1+(Cpl(Tb-Tf)/ λ)∴ q=1.11

Feed line is a line passing through xF and having a slope of 10 and intercept -8.0764Now, from x- y plot

Rmin / (Rmin + 1) = (xD-y`)/(xD-x`)∴ Rmin =2.734

Takin Optimum reflux ratio as 1.5 times of Rmin, we haveR= 1.5*2.734 = 4.1

From the equilibrium curve we obtain, Number of ideal stages, Ni=18

23

Assuming efficiency 80%Number of real stages, Na = 18/0.8

= 21(approx.)6.2 In tern al d esign estima tion:

From the McCabe Thiele curve, we getSlope of the bottom operating line = 1.01Slope of top operating line = 0.809

From the material Balance,Feed =4747.51/60.91= 77.95 kmol/hTop product Vapor rate, V = D*(1+R)=69.71(1+4.1) = 355.521 kmol/hLiquid rate = L = V*Slope of top operating line = 287.616 kmol/hr

An overall mass balance gives:

Bottom product, B=8.24 kmol/h

Slope of the bottom operating line = Lm`/Vm` =1.01

Vm`= Lm`-B

Lm`= 1.01Vm`

Vm`= 1.01Vm`-B

Vm`= 8.24/0.01 = 824 kmole/hr

Lm`= 824 + 8.24 = 832.24 kmole/hr

Top:

Bottom:

ρv= 3.038 kg/m3

ρl= 934.360 kg/m3

Surface tension, σT=27*10-3

ρv= 3.119 kg/m3

ρl= 905.346 kg/m3

Surface tension, σB =32.3*10-3

Calculating flooding velocity:

FLV bottom = 1.01 (3.119/905.346)1/2 =0.0512

FLV top = 0.809 (3.038/934.360)1/2 =0.046

24

Fig: Flooding Velocity, sieve plates (Fig 11.27 from Chemical Process Design by R.K Sinnott)

Taking plate spacing as 0.7m, from the above figure,

Base K1=0.12Top K1=0.13

Using correction for surface tension,

We get,

Base K1 = (32.3*10-3/0.02)0.2 *0.12 =0.132Top K1 = (27*10-3/0.02)0.2 *0.13 =0.136

Calculations of flooding velocity:

∴ Base uf = 0.132 (905.346-3.119/3.119)1/2 =2.248m/s∴ Top uf =0.138 (934.360-3.038/3.038)1/2 =2.4162m/s

25

Design for 85 per cent flooding at maximum flow rate

∴ Base uv=2.245*0.85 =1.90825 m/s∴Top uv =2.4162 *0.85 =2.0537 m/s

Maximum volumetric flow-rate:

∴ Base = 824*70.46/3.119*3600 =5.1722 m3/s∴ Top =355.521*59.77/3.038*3600 =1.9429 m3/s

Net area required:

∴ Base = 5.1729/1.90825 = 2.71 m2∴ Top = 1.9429/2.0537 = 0.946 m2

As first trial take downcomer area as 12 per cent of total.

Column cross-sectioned area:Base =2.71/0.88 =3.0795 m2

Top =0.946/0.88 =1.075 m2

Column Diameter :

Base = (3.0795*4/3.14)1/2 =1.98mTop = (1.075*4/3.14)1/2 =1.17m

As column is of uniform diameter, using same diameter above and below feedWe take Column diameter =1.98m

Liquid flow pattern

Maximum volumetric liquid rate=832.24*70.48/3600*905.346 =1.79*10-2 m3/sUsing the liq flow rate, a single pass tray can be selected (Ref. fig 11.28 R.K. Sinnott)

Provisional plate design:

Column diameter, Dc =1.98 mColumn area, Ac = 3.0795 m2

Down-comer area, Ad =0.12*0.50 = 0.36954 m2, at 12 per centNet area, An = Ac -Ad=3.0795- 0.36954= 2.70996 m2

Active area, Aa = Ac -2Ad =3.0795 -2*0.36954= 2.34042 m2

Hole area, Ah (take 10 per cent Aa as first trial) = 0.234042 m2

Weir length: the chord/weir length will normally be between 0.6 and 0.85 of the column diamter. Best intial guess would be 0.76 of column ia. Therefore weir length = 0.76*1.98 =1.5048

26

Take ,weir height = 70mmHole size =5 mmPlate thickness = 5 mm

Check f or Weep in g:

Maximum liquid rate=832.24*70.48/3600 =16.29 kg/secMinimum liquid rate, at 70 per cent turn-down = 0.7*16.29 =11.40 kg/sec

Height of liquid crest over the weir

Maximum how at maximum liquid rate =39.22 =39 mm liquid(approx.) Minimum how at minimum liquid rate =31 mm liquidat minimum rate hw +how =70+ 31=101mm

From above figure K2=31

27

Minimum vapour velocity

uh(min) =7.157 m/s

Actual minimum vapour velocity =0.7*5.1729/0.234042 =15.47m/sThus the minimum operating rate will be well above weep point.

Plate pressure drop:

Dry plate dropMaximum vapour velocity through holes

uh =5.1729/0.234042 =22.1m/s

From Figure below, for plate thickness/hole diameter= 1, and Ah/Ap = Ah/Aa = 0.1,C0 = 0.84

28

hd=121mm liquidhr = 12.5*103/905.346=13.8mm

total plate pressure drop= ht = hd + hr + hw + how

= 244mm liquid

Downcomer liquid back up:

Downcomer pressure loss: The down comer area and plate spacing must be such that the level of the liquid and froth in the down comer is well below the top of the outlet weir on the plate above. If the level rises above the outlet weir the column will flood.

Hap =hw-10 = 60 mmAap=0.60*60*10-3 =0.036

Hdc =41.46mmHb=0.384 m liquid

0.384<0.385So plate spacing is acceptable

Residence Time:

Check residence time=0.36954*0.382*905.346/16.29 =7.84

As residence time is greater than 3 sec therefore satisfactorily.

Check entrainment:

Percent flooding = uv /uf, uv = vapor velocity based on net area

An upper limit of Ψ = 0.1 is acceptable

Uv=5.1729/2.70996 =1.9088 m/sPercent flooding =1.9088/2.245=85%

29

Flv=0.0592Ψ=0.06>0.1 ∴ acceptable

6.3 Plate Design :

We are considering sectional construction platesAllowing 125 mm unperforated strip round plate and 125 mm wide calming zone

From Figure below, at lw/Dc =1.5048/1.98 = 0.76Φ=99o

angle subtended by the edge of the plate D 180 -99 = 810

mean length, unperforated edge strips =(1.98-125*10-3)3.14*(81/180) =2.621m

area of unperforated edge strips 125*10-3*2.621=0.327625m2

mean length of calming zone, approx. = weir length * width of unperforated strip= 1.5048 *125*10-3=1.6298 m

area of calming zones =1.6298*125*10-3=0.40785m2

total area for perforations, Ap =2.34042-0.40785-0.327625=1.604945m2

Ah/Ap = 0.234042/1.604945= 0.146From Figure , lp/dh = 2.6; satisfactory, within 2.5 to 4.0.

30

Number of holesArea of one hole = 1.964*10-5m2

Number of hole = 0.234042/1.964*10-5

=11925

Design pressure =1atm=1.01325 bar0.101325N/mm

Design pressure, take as 10 per cent above operating pressure

Therefore design pressure =0.101325*1.1 =0.1114575 N/mm

Typical design stress =145 N/mm2

Cylindrical section:

E = (0.1114575*1.98*103)/(2*145-0.1114575) = 0.76mmSay 1mm

31

Choosing Domed head and calculating its thickness:

1. Try a standard dish head(torisphere)

Crown radius Rc=Di=1.98mKnuckle radius =0.06*1.98=0.1188mAssuming joint efficiency, J=1

Cs=1.77

∴ Thickness of the torispherical head e =

1.346mm

2. Trying standard ellipsoidal head, major to minor axes ratio =2:1

∴ thickness of ellipsoidal head, e = 0.76(Say 1mm)

Hence we have ellipsoidal head as probably the most economical. ∴ Taking same thicknessas wall 1 mm.

from column design:Height, between tangent lines= 15 mDiameter=1.98mSkirt support, height =3 m21 sieve plates, equally spacedMaterial of construction, stainless steel, design stress 145 N/mm2 at design temperatureOperating pressure 1.01325 barVessel to be fully radiographed (joint factor 1)

32

Design pressure take 10% above operating pressure =1.01325*1.1*1/10=0.1114575N/mm2

Minimum thickness required for pressure loading = (0.1114575*1.98*103)/(2*145-0.1114575)

= 0.76

A much thicker wall will be needed at the column base to withstand the wind and dead weight

loads.

As a first trial, take minimum thickness as 5mm

Approximate weight of cylindrical vessels with domed end is calculated as:

For steel vessel, we have,

Cv = 1.15(vessels with plates)

Dm = 1.98+5*10-3=1.985m

Hv=15m

T=5mm

Wv=45.44kN

Obtaining weight of plates,

Plates area=3.14*1.982/4 =3.078m2

Weight of 1 plate =1.2*3.078=3.6936 kN

For 21 plates, total weight =21*3.6936=77.56kN∴ Total wt=45.44+77.56=123kN Wind loading

Dynamic wind pressure=1280N/m2

Mean diameter=1.98+2(5*10-3) = 1.99 m

Loading (per linear metre)=1280*1.99 = 2547.2N/m

Bending moment at the bottom tangent line Mx = 2547.2*152/2 =286560N/m

33

Analysis of stress at the bottom tangent line,

σL=0.1114575*1.98*103/4*5=11.03 N/mm2

σh=0.1114575*1.98*103/2*5=22.06 N/mm2

Dead weight stress calculation,

σw=3.9468 N/mm2(compressive)

Bending stress

Output dia, Do=1.98*103+2*5=1990mm

Moment of inertia, Iv=1.535*1010mm4

σb=18.575 N/mm2

∴ Resultant longitudinal stress=

σz (upwind) = σL-σw+σb =25.6582 N/mm2

σz (downwind) = σL-σw+σb =-11.4918 N/mm2

Greatest difference between the principle stresses will be on downside =

22.06-(-11.4918)=33.5518 N/mm2 which is well below allowable design stress

34

Check elastic stability (buckling)

σc = 50.25 N/mm2

The maximum compressive stress will occur when the vessel is not under pressure

3.9468+18.575 = 22.5218 > 50.25, well below the critical buckling stress.

Skirt support :

Try a straight cylindrical skirt (θ=90) of plain carbon steel, design stress 135 N/mm2

and Young’s modulus 200,000 N/mm2 at ambient temperature.

Maximum dead weight will occur when the vessel is full of water

Approximate weight = (3.14*1.982*15*1000*9.81)/4

= 452.856kN =453 kN∴ Weight of vessel = 123kN∴ Total weight = 453+123=576 kN

∴ Wind loading =2.5472*(15+3)2/2 =412.6464 kNm

Taking initial skirt thickness same as bottom thickness 5mm

σbs35

σbs =26.74 N/mm2

W(test)=453kN

σws(test)=14.54 N/mm2

W(operating)=123kN

σws(operating)=3.946 N/mm2

Maximum σs(compressive)=26.71+14.54=41.25 N/mm2

Maximum σs(tensile)=26.71-3.964=22.746 N/mm2

Take J=1

The skirt thickness should be such that under the worst combination of wind and dead-weight

loading the following design criteria are not exceeded:

22.746 125

41.25 63.13

Both criteria are satisfied, add 2 mm for corrosion, gives a design thickness of 7mm

36

Base ring and anchor belts:

Scheiman gives the following guide rules which can be used for the selection of the

anchor bolts:

1. Bolts smaller than 25 mm (1 in.) diameter should not be used.

2. Minimum number of bolts 8.

3. Use multiples of 4 bolts.

4. Bolt pitch should not be less than 600 mm (2 ft).

Approximate pitch circle diameter =2.2m

Circumference of bolt circle=2200

No of bolts required at minimum bolt spacing=2200 /600=11.51

Closest multiple of 4=12

the bolt area required is given by:

Where,

Ab =area of one bolt at the root of the thread, mm2,

Nb = number of bolts,

fb =maximum allowable bolt stress, N/mm2;

typical design value 125 N/mm2 (18,000 psi),

Ms = bending (overturning) moment at the base, Nm,

W = weight of the vessel, N,

Db = bolt circle diameter, m.

Ms=412.6464kNm

Ab=418mm2

Bolt root diameter=(418*4/3.14)=23mm

37

The total compressive load on the base ring is given by:

Fb=153.868kN/m

Take bearing pressure 5N/mm2

Lb=153.86*103/5*103=30.7736mm

It is not too large so a cylindrical skirt can be used

Bolt spacing=3.14*2.2*103/12=575mm

Use M24 bolts (BS 4190:1967) root area = 418 mm2

Actual width require=Lr+ts+50

=76+7+50=133mm

Where

Lr =the distance from the edge of the skirt to the outer edge of the ring(from figure 13.30,coulson

Richardson volume 6( 4th edition)).

Ts=skirt thickness

actual bearing pressure on base:

fc` = 153.868*103/133*103=1.156 N/mm2

base ring thickness,

Hence, the thickness of base ring = tb=11.96=12 (approx.)

38

C h a pter 7

COST ESTI MATI ON

7.1 Cost of Distill ation tow er:

Trays towers: The cost of tray towers can be calculated using the following formulae,

C = 1.218 [ f1*Cb + N*f2*f3*f4*Cr + Cp1 ], where the constants can be calculated as,

Cb= 1.218 exp [ 7.123 + 0.1478 (ln W) + 0.02488 (ln W)2 + 0.01580 (L/D) ln (Tb / Tp)] Cr= 457.7 exp(0.1739 D) , 2 < D <16 ft tray diameterN = number of trays

Cp1= 249.6 D0.6332 * L0.8016

The material of construction is taken as stainless steel 316. Hence, we get the values from cost estimation datasheet as:

f1=2.1f2 =1.401 + 0.0724Df3=0.95f4=2.25/ (1.0414)N

where,Tb is the thickness of the shell at the bottom.Tp is the thickness required for the operating pressure. D is the diameter of the shell and tray.L is the tangent to tangent length of the shell.

From design calculation we have,

D=1.98m = 6.496 ftL= 15 m = 49.21ft

And, W=27651.5 lbs And, Tb=1mmAnd, Tp=5mm

Hence, we have the values as,

Cb=11392.66914Cr=1416.39239Cp1=18543.01705 f1=2.1

39

f2 =1.401 + 0.0724D =1.87 f3=0.95f4=2.25/ (1.0414)21 = 0.96

Substituting the values of the constants, we get the cost of the distillation tower as,

C = 113511.0705 $

7.2 Cost Estima tion O f Overall Plan t

Using the sixth-tenth factor rule,

C2 = C1 ( Q2 / Q1)n where,

C1 = Fixed capital cost of a plant of Capacity Q1, andC2 = Fixed capital cost of a plant of Capacity Q2

n= 0.6

For the year 2006, we have the capacity of a carbonylation plant as Q1 = 129 TPD which has a FCI of C1 = $ 18000000, whereas the capacity of our plant for which FCI is to be calculated is Q2 = 100 TPD.

Hence, our plant’s fixed capital investment for the year 2006 can be calculated as

C2 = 18000000 x (100 / 129)0.6

= $ 15.45 x 106

Using the cost indexes formulae, cost of the plant in 2009 can be calculated as:

(Cost of plant in 2009 / Cost of plant in 2006) = (Cost index in 2009 / Cost index in 2006)∴ Cost of plant in 2009 = $ 15.45 x 106 *(521.9/499.6)

= $ 16.1 x 106

= Fixed Capital Investment (FCI) required

= Rs.857.28 x 106

40

(Using the table 26 from Plant Design and Economics by Peter & Timmerhaus)

Estimation of capital investment cost (showing individual costs)

I Direct cost: (70 - 85 % of FCI )

A. Calculating Equipment + installation + instrumentation + piping +electrical, etc related costs

1. Purchased Equipment (PEC) (15 - 40% of FCI) Taking PEC as 25% of FCI = Rs 214.32 x 106

2. Installation including insulation and painting ( 25 - 55% of PEC) Taking 30% of PEC = Rs 64.296 x 106

3. Instrumentation and Controls, Installed (6 - 30 % of PEC) Taking 25% of PEC = Rs 53.58 x 106

4. Piping, Installed (10 - 80 % of PEC)Taking 30% of PEC = Rs . 64.296 x 106

5. Electrical, Installed (10 - 40% of PEC) Taking 25% of PEC = Rs. 53.58 x 106

B. Building, process and auxiliary (10 - 70% of PEC) Taking 40% of PEC = Rs.85.728 x 106

C. Service Facilities and Yard Improvements ( 40 - 100% of PEC) Taking 60% of PEC = Rs.128.592 x 106

D. Land ( 1- 2% of FCI or 4- 8% of PEC)Taking 5% of PEC = Rs. 10.716 x 106

∴Total Direct Cost = Rs.675.108 x 106

II Indirect Costs (15 - 30 % of FCI)

A. Engineering and Supervision ( 5 - 30 % of Direct Cost) Taking 10% of Direct cost = Rs. 67.5108 x 106

B. Construction Expense and Contractors Fee (6 - 30% of Direct cost ) Taking 10% of Direct costs = Rs. 67.5108 x 106

C. Contingency (5- 15% of FCI)Taking 5.5% of FCI = Rs. 42.864 x 106

∴ Total Indirect Cost = Rs 177.8856 x 106

41

III Working Capital (10 - 20% of TCI)Taking 15% of TCI = Rs. 151.2846 x 106

IV Total Capital Investment (TCI)TCI = FCI + Working Capital∴ TCI = Rs. 1008.564 x 106

(Using the table 27 from Plant Design and Economics by Peter & Timmerhaus)Estimation Of Total Product Cost (Showing individual components):

I Manufacturing Cost

A. Fixed Charges (10 - 20% of TPC)

1. Depreciation ( 10% of FCI + 2 - 3% of building value for building ) Taking 10% of FCI + 2.5% of Building value = Rs. 87.8712 x 106

2. Local Taxes (1-4% of FCI )Taking 4% of FCI = Rs 34.2912 x 106

3. Insurance (0.4 - 1% of FCI)Taking 0.7% of FCI = Rs. 6.00 x 106

∴ Total Fixed Charges = Rs. 128.1624 x 106

Total Product Cost, TPC = fixed charge/0.15

= Rs. 854.416

B. Direct Production Costs ( about 60 % of TPC)

1. Raw Materials (10 - 50 % of TPC)Taking 10% of TPC = Rs . 85.4416 x 106

2. Operating Labor ( 10 - 20 % of TPC )Taking 15% of TPC = Rs.128.1624 x 106

3. Direct Supervisory and Clerical Labor ( 10 - 25 % of Operating labor) Taking 15% of Operating Labor = Rs. 19.224 x 106

4. Utilities ( 10 - 20% of TPC )Taking 10 % of TPC = Rs 85.4416 x 106

5. Maintenance and Repairs ( 2- 10% of FCI ) Taking 5% of FCI = Rs. 42.864 x 106

6. Operating supplies ( 10 - 20% of cost for maintenance and repairs) Taking 15% of cost for maintenance and repairs = Rs. 6.4296 x 106

42

7. Laboratory Charges ( 10 - 20% of Operating Labor ) Taking 15% of Operating Charges = Rs. 19.224 x 106

8. Patents and Royalties ( 0 - 6% of TPC ) Taking 2% of TPC = Rs 17.088 x 106

∴ Total Direct Production Cost = Rs 403.8752 x 106

C. Plant Overhead Cost ( 5 - 10% of TPC)Taking 7% of TPC = Rs. 59.809 x 106

II General Expenses

A. Administrative Costs ( 2- 6% of TPC)Taking 5% of TPC = Rs. 42.708 x 106

B. Distribution and Selling Costs ( 2 - 20% of TPC ) Taking 18% of TPC = Rs. 153.79488 x 106

C. Research and development cost ( 5% of TPC ) Taking 5% of TPC = Rs. 42.7208 x 106

D. Financing ( 0- 10 % of TCI )Taking 5% of TCI= Rs. 50.4282 x 106

∴ Total General Expenses = Rs. 289.66468 x 106

∴ Manufacturing cost = total product cost – general expenses

= 564.75132

7.3 Plan t Econ omics(P r of it and RoR):

Capacity of Acetic acid produced = 100 TPD Selling price of Acetic acid =36000 per ton

∴ Total income = selling price x qty of product produced= 100*36000*310= Rs. 1116 x 106 per annum.

Gross Earning = Total income - Total product cost= 1116 x 106 – 854.416 x 106

= Rs 261.584 x 106

per annum

Tax on gross earning = 50% of gross earning.

Net Profit = Gross earning [ 1 - tax rate ]= Rs. 130.792 x 106

43

Rate of return = Net profit / Total capital investment= 130.792 x 106 / 1008.564 x 106

= 0.129 = 12.9%

7.4 Break even p oin t calcul ation :

Let the break-even point is achieved at a production of X TPY of Acetic Acid. Now, for break-even point to be obtained, we have:

Total income = Total product cost

Or, X*36000=854.416 x 106

∴ X= 23733.78 Ton per year

The plant production is 100TPD,∴ Break even point =23733.78/100=237.3378=238 days =0.76 years

44

R eferenc e s

1. Perry’s Chemical Engineering Handbook 8th edition.

2. Unit Operations of Chemical Engineering by McCabe, Smith and Harriott.

3. Chemical Product Design by R.K. Sinnott

4. Indian Chemical Industry XIIth Five Year Plan (2012-2017).

5. “The CativaTM Process for the Manufacture of Acetic Acid” By Jane H. Jones, B.P

Chemicals Ltd.

6. United States Patent, Garland et. al. , Processes for the production of Acetic Acid.

7. Process Plant Design and economics by Peter And Timmerhaus.

8. Simulation Software: ChemCad

9. Websites:

w w w . I c is.com

w w w.Ch e r e so u r c e s . c om

M a te r i a l S a fe t y D a t a S h eet ACETIC ACID, GL AC IAL

SECTION 1 – Chemical Product and Company Identification

MSDS Name: ACETIC ACID, GLACIAL

Synonyms: Acetic acid, glacial, Ethanoic acid, methanecarboxylic acid.

Formula: CH3COOHMolecular Wt: 60.05

SECTION 2 – Hazards Identification

EMERGENCY OVERVIEW

Appearance: Acetic acid is a clear, colourless liquid above 16 °C and colourless, ice-like crystals below 16 °C. Has a strong, pungent odour of vinegar. Hygroscopic. COMBUSTIBLE LIQUID AND VAPOUR. Vapour is heavier than air and may spread long distances. Distant ignition and flashback are possible. Harmful if inhaled or swallowed. Vapour is irritating to the respiratory tract. May cause lung injury--effects may be delayed. Concentrated solutions are CORROSIVE to eyes and skin. Causes permanent eye damage, including blindness, and skin burns, including tissue death and permanent scarring. May be an aspiration hazard. Swallowing or vomiting of the liquid may result in aspiration into the lungs.Target Organs: Teeth, eyes, skin, mucous membranes.

Potential Health Effects

Primary Route(s) of Entry: Inhalation and ingestion. Skin contact. Skin absorption.Effects of Acute Exposure: May be fatal by ingestion, inhalation or skin absorption.

Corrosive.LD50/LC50: CAS# 64-19-7: Inhalation, mouse: LC50 = 5620 ppm/1H. Oral, rat: LD50 =

3310 mg/kg. Skin, rabbit: LD50 = 1060 mg/kg.Eyes: Concentrated solutions are corrosive and can cause permanent eye damage, including

blindness.Skin: The degree of irritation depends on the concentration of acetic acid and the length of exposure. Highly concentrated solutions or pure acetic acid can cause corrosive tissue injury with deep burns, tissue death and permanent scarring. Less concentrated solutions can cause mild to severe irritation.Ingestion: Causes severe corrosive injury to the gastrointestinal tract and stomach. Acetic acid may be aspirated (inhaled into the lungs) during ingestion or vomiting. Aspiration of even a small amount of liquid could result in a life-threatening accumulation of fluid in the lungs. Severe lung damage (edema), respiratory failure, cardiac arrest and death may result. Ingestion is not a typical route of occupational exposure.Inhalation: Accidental inhalation of high concentrations may cause corrosive injury to the respiratory tract, inflammation, nose and throat irritation, shortness of breath, cough, wheezing, and reversible lung injury in people exposed occupationally. Effects may be delayed.Effects of Chronic Exposure: Repeated inhalation may cause pulmonary edema, bronchopneumonia, or chemical pneumonitis. Prolonged or repeated exposure may cause

dermatitis, erosion of teeth, conjunctivitis and cumulative systemic injury. To the best of our knowledge, the chronic toxicity of this substance has not been fully investigated.

SECTION 3 – First Aid Measures

Eyes: Flush skin and eyes with copious amounts of water for at least 20-30 minutes, holding lids apart to ensure flushing of the entire surface. Contact with liquid or vapor causes severe burns and possible irreversible eye damage. Get medical aid immediately.

Skin: Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 20-30 minutes while removing contaminated clothing and shoes. Wash clothes before reuse. Discard shoes.

Ingestion: Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Consult a physician immediately. Never give anything by mouth to an unconscious person. Keep patient warm and quiet.

Inhalation: Get medical aid immediately. Remove patient from exposure to fresh air immediately. Administer approved oxygen supply if breathing is difficult. Administer artificial respiration or CPR if breathing has ceased. Call a physician. Symptoms of pulmonary edema can be delayed up to 48 hours after exposure.

Notes to Physician: Treat symptomatically and supportively. Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instance of inhalation or skin contact.

Antidote: No specific antidote exists.

SECTION 4 – Fire Fighting Measures

General Information: COMBUSTIBLE LIQUID AND VAPOUR. Can form explosive mixtures with air at, or above, 39 °C. Vapour is heavier than air and may travel a considerable distance to a source of ignition and flash back to a leak or open container. Vapours from warm liquid can accumulate in confined spaces, resulting in a flammability and toxicity hazard. Closed containers may rupture violently when heated. NOTE: The fire properties of acetic acid depend upon the strength of the solution. In concentrated form, its properties approach those of glacial acetic acid. Reacts with most metals to form highly flammable hydrogen gas, which can form explosive mixtures with air. Fire-fighters should wear a positive pressure self-contained respirator (SCBA) and full-body encapsulating chemical protective suit.

Extinguishing Media: For small fires, use dry chemical, carbon dioxide, water spray or alcohol-resistant foam. Use water spray to cool fire-exposed containers or disperse vapours if they have not ignited.

Auto-ignition Temperature: 867-869 °F (463-465 °C); also reported as 516 °F (961 °C)

Flash Point: 39-43 °F (103-109 °C) (closed cup)

NFPA Rating: Health 3; Flammability 2; Instability 0.

Explosion Limits: Lower: 4% (also reported as 5.3-5.4%); Upper: 16% (also reported as19.9%).

Special Fire and Explosion Hazards: Flash back along vapour trail may occur; eliminate sources of ignition. Emits toxic fumes under fire conditions. Empty container may contain explosive or flammable residue. Hazardous combustion products – Oxides of carbon.

SECTION 5 – Accidental Release Measures

General Information: Use proper personal protective equipment as indicated in Section 7.

Spills/Leaks: Restrict access to area until completion of clean-up. Ensure clean-up is conducted by trained personnel only. Use water spray to dilute spill to a non-flammable mixture. Avoid run-off into storm sewers and ditches which lead to waterways. Extinguish or remove all ignition sources. Provide ventilation. Do not touch spilled material. Contain spill with earth, sand, or absorbent material which does not react with spilled material. Remove liquid by pumps or vacuum equipment. Place in suitable, covered, labelled containers.

Steps to be taken in case material is released or spilled: Evacuate. Shut off all sources of ignition. Soak up spill with absorbent material which does not react with spilled chemical. Put material in suitable, covered, labelled containers. Flush area with water. Contaminated absorbent material may pose the same hazards as the spilled product.

Waste disposal method: Burn in a chemical incinerator equipped with an after burner and scrubber. According to all applicable regulations. Avoid run-off.

SECTION 6 – Handling and Storage

Handling: This material is a CORROSIVE, COMBUSTIBLE LIQUID. Inspect containers for damage or leaks before handling. Immediately report leaks, spills or failures of the engineering controls. Avoid all ignition sources. Use in the smallest possible amounts, in a well-ventilated area, separate from the storage area. Avoid generating vapours or mists. Prevent the release of vapours or mists into the air. Do not use with incompatible materials. See Section 10 for more information. Never return contaminated material to its original container. Keep containers tightly closed when not in use. Empty containers may contain hazardous residues. Never add water to a corrosive. Always add corrosives to COLD water. When mixing with water, stir small amounts in slowly. Never perform any welding, cutting, soldering, drilling or other hot work on an empty vessel, containers or piping until all liquid and vapours have been cleared.

Storage: Store in a cool, dry, well-ventilated area, out of direct sunlight and away from heat and ignition sources. Store away from oxidizers and corrosives and other incompatible materials such as most common metals. See Section 9 for more information. Inspect all incoming containers to make sure they are properly labelled and not damaged. Keep quantity stored as small as possible. Keep containers tightly closed. Empty containers may contain hazardous residues. Have appropriate fire extinguishers and spill clean-up equipment in or near storage area.

SECTION 9 – Exposure Control/Personal Protection

Engineering Controls: Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits.

Exposure Limits:Chemical Name OSHAAcetic acid, glacial 10 ppm TWA (25 mg/m3 TWA);OSHA Vacated PELs Acetic acid: 10 ppm TWA; 25 mg/m3 TWA.

Personal Protective EquipmentEyes: Wear appropriate protective eyeglasses or chemical safety goggles as described byOSHA’s eye and face protection regulations in 29 CFR 1910.133.

Skin: Wear appropriate protective neoprene or polyethylene gloves to prevent skin exposure. Apron or clothing sufficient to protect skin.

Clothing: Wear appropriate protective clothing to prevent skin exposure. Neoprene, PVC or polyethylene apron or clothing sufficient to protect skin.

Respiratory Protection: Follow the OSHA respirator regulations found in 29CFR 1910.134. Always use a NIOSH-approved respirator when necessary. Wear appropriate OSHA/MSHA approved chemical cartridge respirator. If more than TLV, do not breathe vapour. Wear self- contained breathing apparatus.

Ventilation: Use only in a chemical fume hood. Adequate ventilation to maintain vapour/dust below TLV.

Other Protective Equipment: Make eye bath and emergency shower available.

SECTION 8 – Physical and Chemical Properties

Physical State: Liquid

Appearance: Colourless

Odour: Pungent odour – acetic odour (vinegar-like)

pH: 2.4 (1 M solution in water)

Vapour Pressure: 1.52 kPa (11.4 mm Hg) @ 20 °C

Vapour Density: 2.07 (air = 1)

Evaporation Rate: 0.97 (n-Butyl acetate = 1)

Viscosity-Dynamic: 1.22 mPa.s (100% w/w), 2.39 mPa.s (90% w/w) @ 20 °C.

Boiling Point: 100% (w/w): 117.87 °C (244.2 °F)

Freezing/Melting Point: 100% (w/w): 16.635 °C (61.9 °F);

80.6% (w/w): -7.4 °C (18.7 °F)

Decomposition Temperature: No information available.

Solubility: Soluble in all proportions in water, ethanol,

acetone, diethyl ether, glycerol and benzene.

Specific Gravity/Density: 100% (w/w): 1.0495 @ 20 °C;

80% (w/w): 1.08 @ 15 °C

Molecular Formula: C2H4O2

Molecular Weight: 60.0268

SECTION 9 – Stability and Reactivity

Chemical Stability: Stable at room temperature in closed containers under normal storage and handling conditions.

Conditions to Avoid: Incompatible materials, ignition sources, sparks or flame, excess heat.

Incompatibilities with Other Materials: Reacts with most common metals to produce hydrogen. Oxidizing agents, acids, alcohols, alkalies, amines, peroxides. Acetaldehyde, 2- aminoethanol, ammonium nitrate, bromine pentafluoride, chlorine trifluoride, chlorosulfonic acid, chromic acid, chronic anhydride + acetic anhydride, diallyl methyl carbinol + ozone, ethylene diamine, ethyleneimine, hydrogen peroxide, nitric acid, nitric acid + acetone, oleum, perchloric acid, permanganates, phosphorus isocyanate, phosphorus trichloride, potassium hydroxide, potassium-t-butoxide, sodium hydroxide, sodium peroxide, and xylene. See NFPA Fire Protection Guide for specifics.

Hazardous Decomposition Products: Carbon monoxide, carbon dioxide.

Hazardous Polymerization: Has not been reported.

Reaction Product(s): Contact with incompatible materials may cause explosion or fire.

SECTION 10 – Toxicological Information

RTECS: CAS# 64-19-7: AF1225000.

LD50/LC50: CAS# 64-19-7: Inhalation, mouse: LC50 = 5620 ppm/1H. Oral, rat:

LD50 = 3310 mg/kg. Skin, rabbit: LD50 = 1060 mg/kg.

Carcinogenicity: CAS# 64-19-7: Not listed as carcinogen by ACGIH, IARC,

NIOSH, NTP, OSHA, or CA Prop 65.

Epidemiology: Standard Draize test: Skin, human – 50 mg/24H, mild reaction.

Teratogenicity: Effects of Newborn: behavioral, Oral-rat

TDLo = 700 mg/kg.

Reproductive: Fertility: male index, itt-rat TDLo = 400 mg/kg.

Mutagenicity: There have been no positive reports once the effect of pH on culture media has been controlled.

Neurotoxicity: No information available.

SECTION 11 – Ecological Information

Ecotoxicity: Bluegill (fresh water) TLm = 75 ppm/96H. Goldfish (fresh water)

TLm = 100 ppm/96H. Shrimp (aerated water) LC50 = 100-330 ppm/48H.

Physical: No information available.

Other: None.

Environmental: Substance spreads on soil surface and penetrates at rate dependent on soil type and water content. Substance readily degrades in water and shows little potential for bioaccumulation.