MANUFACTURE OF BUTADIENEUSING n-BUTANE A PROJECT REPORT Submitted by ARVIND C.A. (41501203002) PRAKASH RAO K.R. (41501203015) SURYANARAYANAN K.S. (41501203018) in partial fulfillment for the award of the degree of BACHELOR OF TECHNOLOGY in CHEMICAL ENGINEERING S.R.M. ENGINEERING COLLEGE, KATTANKULATHUR-603 203, KANCHEEPURAM DISTRICT. ANNA UNIVERSITY : CHENNAI - 600 025 MAY 2005 BONAFIDE CERTIFICATE Certified that this project report " MANUFACTURE OF BUTADIENE USING nBUTANE " is the bonafide work of " ARVIND C.A. (41501203002), PRAKASH RAO K.R. (41501203015) and SURYANARAYANAN K.S. (41501203018)" who carried out the project work under my supervision. Dr. R. KARTHIKEYAN Dr. R. KARTHIKEYAN HEAD OF THE DEPARTMENT SUPERVISOR Professor CHEMICAL ENGINEERING CHEMICAL ENGINEERING S.R.M.Engineering College S.R.M.Engineering College Kattankulathur - 603 203 Kattankulathur - 603 203 Kancheepuram District Kancheepuram District ACKNOWLEDGEMENT We are extremely thankful to Prof. R. Venkataramani, Principal, S.R.M Engineering College, for permitting to carry out this project and providing us with all the facilities. We take pride in expressing our deepest gratitude to our project guide, Dr.R.Karthikeyan, Professor and Head, Department of Chemical Engineering, for his invaluable guidance and encouragement at every stage of this project. We extend our thanks to all the staff members of the Chemical Engineering Department for their technical assistance and support. iii NR. For a high yield requirement of butadiene. energy balance. PBR. iv . This project deals with the material balance. ABS.ABSTRACT Butadiene is one of the most important industrial chemicals with applications ranging from polymers and elastomers like SBR. design. the Houdry Catadiene process of dehydrogenation of n-butane has proven most economic. economics and safety aspects of the process. control. SBL. and CR to chemicals like adiponitrile used in the manufacture of Nylon-66. 2 CHEMICAL PROPERTIES 4 1.3.1 PHYSICAL PROPERTIES 3 1.4.3 ENERGY BALANCE 17 2.3. ABBREVIATIONS ix INTRODUCTION 1 1.3 PROPERTIES 3 1.TABLE OF CONTENTS CHAPTER 1 TITLE ABSTRACT iv LIST OF TABLES vii LIST OF FIGURES viii LIST OF SYMBOLS.2 MATERIAL BALANCE 10 2.1 METHODS OF PRODUCTION OF BUTADIENE 6 1.4 LITERATURE REVIEW 2 PAGE NO 6 1.4.2 SELECTION OF PROCESS 7 PROCESS 8 2.1 PROCESS DESCRIPTION 8 2.2 APPLICATIONS 1 1.4 DESIGN 24 2.1 HISTORY 1 1.5 PROCESS CONTROL AND INSTRUMENTATION 36 v . 7 COST ESTIMATION 46 2.8 PROCESS SAFETY 55 2.11 HEALTH.10 STABILIZATION.2. PLANT LAYOUT 38 2.9 MATERIALS OF CONSTRUCTION 62 2. SAFETY AND TOXICOLOGY 64 CONCLUSION 66 REFERENCES 67 vi .6. STORAGE AND TRANSPORTATION 2. 12 Indirect cost factor 48 Table.7 Required data for cooler 20 Table.9 Physical properties data for preheater 24 Table.8 Required data for reboiler 22 Table. Uses of Butadiene 2 Table.14 Exposure limits 65 vii .10 Delivered cost of major equipment 47 Table.5 Required data for reactor 18 Table.2 Physical properties of butadiene 4 Table.4 Required data for preheater 17 Table.13 Auxillary services cost factor 49 Table.6.1.LIST OF TABLES Table.3 Materials entering the absorber 12 Table. Required data for quench tower 19 Table.11 Direct cost factor 47 Table. LIST OF FIGURES Fig.HEAVY ENDS SYSTEM 32 Fig.3 PLANT LAYOUT 38 viii 9 .1 MANUFACTURE OF BUTADIENE Fig.2 BUTADIENE . J / sm2 0C K = thermal conductivity.m3/kmol. kg n = number of stages N. kmol/s GMS = Molar flow rate of inerts to the absorber. m R = Universal gas constant. atm. = Height of transfer unit. m2 B = Molar flow rate of residue. J / kg.T. m/s ύ = vapor flow rate in stripping section kmol/s X = Mole ratio in liquid phase x =Mole fraction in liquid phase ix . m hi = tube side heat transfer coefficient. m F = Molar flow rate of feed. m do = outer diameter. kmol/s de = equivalent diameter. J / sm0c L = Tube length. ABBREVIATIONS AO = surface area.U. atm Pr = Prandtl number PT = pitch.U = Number of transfer units Nu = Nusselt number P = Pressure. kmol/m2s H.K D = Molar flow rate of distillate.LIST OF SYMBOLS.T. J / sm2 0C V = vapor flow rate in rectifying section kmol/s v = Velocity. m di = inner diameter. kmol/s CP = specific heat. J / sm2 0C ho = Shell side heat transfer coefficient. kmol/m2s m = mass. m LMS = Molar flow rate of solvent to the absorber.K RD = Reflux ratio Re = Reynolds number TPD = tons per day UO = overall heat transfer coefficient. 0C λ = Latent heat. 0C ∆TL = log mean temperature difference.s ρ = density.y = Mole fraction in vapor phase Y = Mole ratio in vapor phase ZT = Total height of absorption column. kg / m. m GREEK SYMBOLS α = relative volatility ∆H0R = Standard heat of reaction. kJ/kg µ = viscosity. kcal/kg ∆T = temperature difference. kg / m3 x . The main product is the copolymer of acrylonitrile. A new elastomer 1 .2.K.ZIEGLER and G. the work of K.BERTHELOT produced it by passing a mixture of acetylene and ethylene through a red-hot iron tube. CIAMICIAN and P. is Nitrile rubber (NBR).MILLER. M. After the war. among others. They are also included in the production of cyclododecatriene as a step toward making Nylon-12 and in manufacture of hexabromocylododecane.ARMSTRONG and A. methods were developed for manufacture of useful butadiene polymers. produced from acrylonitrile and butadiene are important. HISTORY E.discovered butadiene in the products obtained on cracking petroleum. Nitrile latices. where 10-15% butadiene is incorporated. 1.CAVENTOU was the first to isolate butadiene by means of pyrolysis of amyl alcohol. APPLICATIONS Butadiene. in 1886. G.1. The stereospecific polybutadiene rubber (PBR) and thermoplastic rubbers containing polybutadiene and polystyrene blocks are growing in importance.MAGNAGHI elucidated the structure of butadiene.E. H. practical interest in this compound and its derivatives developed.NATTA.1. Another important area of use for butadiene is in the field of plastics.LEBEDEW in 1910 discovered that butadiene forms rubber like polymers. INTRODUCTION 1. on polymerization with organometallic catalytic agents led to better quality of rubber. Simultaneously. It is also used in the raw material for production of adiponitrile and hexamethylenediamine as intermediates for production of Nylon-66. It is the main component of the general-purpose rubber designated SBR (70% butadiene and remainder styrene). The third rubber involving butadiene as monomer. in which butadiene and 20 – 60 % acrylonitrile are copolymerised. In 1885. Butadiene was produced on a large scale in Germany prior to World War II and in the USA during the war. Ever since S. A number of latex materials are also produced from butadiene in conjunction with other monomers. butadiene and styrene known as ABS resin. the principal diolefin and four-carbon industrial chemical.chlorobutadiene. The fourth type is chloroprene rubber (CR) where the monomer is 2. is primarily used as a monomer or a co-monomer in production of synthetic rubber. 6 2.7 4.0 8.0 2 .0 13.0 CHEMICALS AND OTHER USES Adiponitrile Others 21.7 11.7 POLYMERS AND RESINS Acrylonitrile-butadiene-styrene(ABS) Styrene-butadiene copolymer(latex) 15.0 23.g.0 5. Uses of Butadiene END USE PERCENTAGE OF TOTAL SYNTHETIC ELASTOMERS Styrene-butadiene rubber(SBR) Polybutadiene(BR) Polychloroprene(neoprene) Nitrile rubber 63.3 32. Table 1..system based on carboxy-terminated butadiene acrylonitrile polymers (CBTN) is being developed as an alternative to urethane technology e. car bumpers. flammable gas at room temperature and atmospheric pressure. Since normal carbon-carbon single bonds are .2-butadiene is much less studied. more thermodynamically stable than molecule with two isolated single bonds. colorless. The s-trans isomer.3. rapid equilibrium allows reactions to take place with either the s-cis or s-trans form. this indicates the extent of double-bond character in the middle single-bond.145 nm. often called the trans form. .1. PROPERTIES 1.3. PHYSICAL PROPERTIES 1.141 nm.154 nm. It is sparingly soluble in water. Upon complexing with metal carbonyl moieties like Fe(CO)3 . slightly soluble in methanol and ethanol. The conjugation of the double bonds makes it 15 kJ/mole. the two terminal bonds lengthen to . Although there is a 20kJ/mole rotational barrier. benzene.3-butadiene is . It has a mildly aromatic odor. and the single-bond. 1. and carbon tetrachloride.148nm.3-Butadiene is a non-corrosive.134 nm. The double-bond length in 1. 3 . and soluble in organic solvents like diethyl ether. is more stable than the s-cis form at room temperature. and the middle bond shortens even more to .1. It is a flammable gas at ambient conditions. mPa.addition is the most important butadiene reaction.902 0 Critical temperature. approximately 1850C. In the production of adipic acid according to a BASF procedure. kJ/mole 88.J/(mole. and at a lower pressure pentene acid ester 4 .0 Critical pressure.5 1.additions with itself (polymerization) and with other reagents.2-addition. On 1. butadiene reacts with carbon monoxide and methanol in two steps under different reaction conditions.MPa 4. liquid.6452 00C . kJ/mole 110. Polymerisation by means of 1. atactic polymers. C 152.411 0 Freezing point. CHEMICAL PROPERTIES Butadiene has two conjugated double bonds and. therefore. C -4. cm /mole 221 Critical density.25 Heat of formation. C -85 Explosion limits in air. in which the vinyl group has an arbitrary steric position.g/ml .7 0 Flash point. Physical properties of butadiene Property Value Molecular formula C4H6 Molecular weight 54. gas. can take part in numerous reactions. C -108.and 1. linear dimerisation and trimerisation. The manufacture of chloroprene (chlorinated hydrocarbons) requires the chlorination of butadiene followed by isomerization and alkaline dehydrochlorination.and 1.s at 0 C . and ring formation.6194 250C Density(gas) (air=1) 1.4. which includes 1.2.Table 2.0 Upper 11.538 0 Refractive Index. at -25 C 1.g/ml at .245 Density (liquid).2.ppm 735 0 Viscosity (liquid).4.3.092 0 Boiling point at atm.9 0 Heat capacity at 25 C.32 3 Critical volume.165 Heat of formation. vol% Lower 2.2. pressure. can also be formed.K) 79. At a higher temperature.4292 0 Solubility in water at 25 C. LITERATURE REVIEW 1. with Cu(I)salts. gives styrene.reacts again with carbon monoxide and methanol to give adipic acid dimethyl ester. In the production of hexamethylenediamine. reacts with butadiene forming a cyclohexane ring. forming 4-vinylcyclohexene-1. Butadiene also reacts in several ways to give 1. when subjected to dehydrogenation or oxidation.4-butanediol. i. Co. cobalt. 2. or Fe catalysts. 1. butadiene undergoes a Diels-Alder reaction with naphthaquinone to give tetrahydroanthraquinone. nickel.4. a dienophile. Pd. Usually. hydrogen cyanide reacts with butadiene in two steps and the adiponitrile thus obtained is hydrogenated to give the diamine. Vinylcyclohexene. which in turn is oxidized to anthraquinone.5-dihydrothiophene-1. which is exclusively a 1. a heat-stable and highly polar solvent.. Complexes with iron. Butadiene readily undergoes a 1. Cyclization. Hydrolysis then leads to the formation of adipic acid. which is a starting material in production of heat-resistant lubricants. Formation of Complexes: Butadiene reacts with numerous metal compounds to form complexes.4.. Diels-Alder Reaction: The Diels-Alder reaction is one of the best known reactions of butadiene. which are used in the extraction of butadiene from C4-hydrocarbon mixtures. and platinum are also well known.g. In the synthesis of anthraquinone. Linear dimerisation and trimerisation: Butadiene forms linear dimers or trimers in the presence of Ni. can also take place with a second molecule of butadiene as the dienophile component.4-addition. METHODS OF PRODUCTION OF BUTADIENE 5 . Butadiene undergoes hydroformylation to give valeric aldehyde.1. e.4-addition with sulfur dioxide forming a cyclic sulfone. This addition reaction. This compound is converted into sulfolan. on catalytic hydrogenation.1-dioxide. Dimerisation of butadiene and simultaneous reaction with carbon monoxide and alcohol leads to the synthesis of pelargonic acid. palladium. an olefin with an activated double bond.e. Oxidative Dehydrogenation of n-Butenes: The conversion and the selectivity of the dehydrogenation of n-butenes to butadiene can be significantly improved by removing the hydrogen from the equilibrium. The main cracking feed stock is ethane. Dehydrogenation of n-Butane: The best known one-step dehydrogenation is the Houdry Catadiene process. highly endothermic pyrolysis reaction. 1. subsidized agricultural surpluses. which has been in operation on a commercial scale since 1943. C4H8 + 1/2O2 C4H6 + H2O The addition of oxygen to the dehydrogenation reaction of butane is not meaningful because at the high temperatures required. Oxidative Dehydrogenation of Butane with Halogen: Shell has developed a one-step dehydrogenation of butane to butadiene using iodine as the hydrogen acceptor. which manufacture cheap ethanol from carbohydrates or in the EEC with its enormous.2 SELECTION OF PROCESS 6 . this process has proven most economic. giving rise to undesired byproducts. Production from ethanol: 2CH3CH2OH CH2=CH-CH=CH2 + H2 + 2H2O It is the method of choice in countries. The addition of iodine enables a high conversion and yield of butadiene. These methods are no longer used as the production of acetylene requires a large amount of energy and is very expensive.4. The addition of oxygen causes the oxidation of hydrogen to water. Steam Cracking: Steam cracking is a complex. but has the disadvantage of causing serious corrosion problems in the plant.oxygen reacts with the reaction products. If a high yield of Butadiene is required. which yields only a little C4 hydrocarbons and is thus not suitable as a route to butadiene.Production from Acetylene: The large-scale industrial production of butadiene from acetylene has been carried out in Germany using two processes. (3) azeotropic distillation with ammonia. compressed. which is purified by (1) absorption using cuprous ammonium acetate (CAA).If a high yield of Butadiene is required.2 Kcal (b) Side reaction: C4H10 C4H8 + H2 n-butylenes A refinery gas of C4/C5 cut containing predominantly n-butane with some isopentane is mixed with recycle gas and preheated to reaction temperature prior to contact with a catalyst in a fixed bed. The overhead is fractionated to yield crude butadiene at the top. 120-150 mm absolute. 2. dropping to 5500C at the end before switching to regeneration. The temperature of reaction at the start of the make period is 6500C. (2) extractive distillation with furfural. ∆H = +32. A pair of reactors forms an adiabatic cycle with the heat of reaction required during the 5-15 minutes “make” period equal to that supplied by the combustion of carbon deposit on the catalyst during the regenerative period. regenerative-heating system. PROCESS DESCRIPTION: DEHYDROGENATION OF BUTANE: CHEMICAL REACTIONS: (a) Main reaction: C4H10 CH2=CH. 7 . PROCESS 2. The product gases are oil-quenched. to force the reaction to the right.1.CH=CH2 + 2H2. cooled and separated from the light ends by absorption in naphtha following by stripping. The pressure is low. the Houdry Catadiene process has proven most economic. A desorption step at higher temperature is followed by distillation.1571 kg (from fresh feed) ≡ 1.0717 kmol ≡ 1-min operation Following reactions are taking place in the reactor: C4H10 n-butane C4H10 n-butane CH2=CH-CH=CH2 + 2H2 ----------. Ammonia is recovered in the distillation tower by water addition. and liquefaction of butadiene to give 98-99% product purity. it is then separated as substantially anhydrous NH3 by fractionation.II n-butylenes 8 . MATERIAL BALANCE REACTOR: BASIS: 62.The more common absorption process involves contact of the close-boiling butadienebutene fraction with lean CAA solution.2. 2.I butadiene C4H8 + H2 ------------. which dissolves butadiene. Mono-olefins may be required. compression. 79 OUTPUT kg C4H10 9 : 248.1072 kmol = 0.643) = 5.643 kmol n-butane reacted in other reactions = 0.3584 – 1.643 x 4 + 0.2867 kmol = 248.2143 kmol = 0.2143 x 2 = 3.0007 kg Conversion of butane is taken as 12 % ∴ Butane entering into the reactor = (1/0.79 kg ∴ Butane from recycle = 5.4287 kmol n-butane reacted in reaction II is taken as 0.643 kmol = 0.2157 kg n-butane reacted for the production of heavy ends is taken as 0.2143 kmol n-butane reacted for the production of light ends is taken as 0.1072 x 58 = 6.7222 kg Butene produced in reaction II = 0.63 .2143 x 56 = 12.643 x 54 = 34.3584 x 58 kg = 310.12)(0.3584 kmol = 5.1072 x 58 = 6.2157 kg Butadiene produced in reaction I = 0.0717 = 4.1072 kmol = 0.Yield is taken as 60 % n-butane reacted in reaction I = 0.63 kg INPUT kg REACTOR C4H10 : 310.0027 kg H2 produced in reactions I and II = 0. 5003 Light ends 6.99 % of solute be removed in the absorber ∴ Mole ratio of solute to inert in the leaving gas mixture = Ya = 3. kg Mol.7222 54 0.6396 kmol Mole ratio of solute to inert in the entering gas mixture = Yb = 5.0007 2 1..0007 Light ends : 6. of kmoles C4H10 248.7222 C 4 H8 : 12. Materials entering the absorber Component Weight .0027 56 0.63 58 4. Wt.2026 Let 99.2867 C 4 H6 34.3.79 6.2157 60 (assumption) 0.8909 Moles of inert (H2 and Light ends) entering absorber through gas mixture (Gms) = 1.643 C 4 H8 12.2157 TOTAL: 310.2143 H2 3.2157 45 (assumption) 0.1393 Heavy ends 6.2513/1. kg/kmol No.0027 H2 : 3.2026x10-3 Mole ratio of solute to solvent (naphtha) entering the reactor = Xa = 0 (as pure naphtha is used) Let Lms be pure solvent used & Xb be mole ratio of solute to solvent leaving the rector Material balance for solute in the absorber: Lms (Xb – Xa) = Gms (Yb – Ya) For minimum solvent rate.79kg ABSORBER: Table. (Lms)min . Xb = Xb* 10 .C 4 H6 : 34.2157 Heavy ends : 6.6396 = 3.79 kg TOTAL : 310.1072 Total 310. 2095 kg Light ends absorbed = 6.59 kg TOTAL : 436.2 = 0.7222 12.9976 Light ends : 6.5 = 3.0007 – 2.6396 ( 3.4052 (Lms)min ( 6.2157 6.003 Light ends : 0.2157 – 6.59 kg 11 .9828 kmol = 0.2157 TOTAL : 436.003 kg Light ends unabsorbed = 6.0027 3.006 Heavy ends : 6.2 times the minimum solvent rate ∴ Lms = 0.8190 kmol Let actual solvent rate be 1.2026x10-3 ) (Lms)min = 0.63 34.0007 6.63 C4H6 : 34.9976 kg H2 absorbed = 3.5 = 6.2095 SOLUTION 248.9976 = 0.2157 NAPHTHA : 125.999 = 6.8 VENT GAS ABSORBER REACTOR EFFLUENT C4H10 : C 4 H6 : C 4 H8 : H2 : Light ends : Heavy ends : kg H2 : 2.5 X ∴ Xb* = Yb / 0.0007 x .7222 C4H8 : 12.2026 – 3.4052 – 0) = 1.2095 = 0.9828 x 128 = 125.0027 H2 : 0.8190 x 1.Let equilibrium relationship be given as Y = 0.999 = 2.006 kg kg NAPHTHA : 125.8 C4H10 : 248.8 kg H2 unabsorbed = 3.2157 x 0.2026 / 0. 2157 C4H10 : 248.STRIPPER: Let all naphtha be removed in the stripper H2 and Light ends are not taken into account.63 C4H6 : 34.7222 C4H8 : 12.3706 kg BUTADIENE TOWER: Let heavy ends be completely removed in the butadiene tower Material balance in the butadiene tower: CRUDE BUTADIENE GAS MIXTURE kg BUTADIENE TOWER kg C4H10 : 248.0027 Heavy ends : 6.0027 C4H8 Heavy ends: 6.2157 Naphtha : 125.3706 kg TOTAL : 427.0027 C4H10 : 248.63 C4H6 : 34.7222 : 12.8 : 248.7222 C4H8 : 12.8 TOTAL : 427.2157 Heavy ends : 6.2157 TOTAL : 301.5706 kg 12 . as they are negligible GAS MIXTURE kg STRIPPER kg Naphtha : 125.0027 Heavy ends: 6.5706 kg TOTAL : 301.63 C4H6 : 34.63 C4H10 C4H6 : 34.7222 C4H8 : 12. Material balance in the mixer – settler: Let 1 kg of CAA be used per kg of crude butadiene kg kg MIXER CAA : 295.0027 TOTAL : 590.7222 C4H8: 12.3549 C4H6 : 34.7098 kg C4H10 : 248.7222 C4H8 : 12.3549 C4H6 : 34.7222 C4H8: 12.63 C4H6 : 34.7098 kg STRIPPER: Let all CAA be removed in the stripper Material balance around stripper: kg kg CAA : 295.MIXER SETTLER: Crude butadiene is sent to mixer – settler where cuprous ammonium acetate (CAA) separates n-butane.63 CAA : 295.0027 TOTAL : 590.3549 SETTLER CRUDE BUTADIENE C4H10 : 248.7222 C4H8 : 12.0798 kg TOTAL : 342.0027 STRIPPER C4H6 : 34.0027 CAA : 295.0798 kg 13 .3549 TOTAL : 342. 0027 C4H8 : 12. C4H8 mixture ∴ NH3 required = 46.8134 kg 14 .AZEOTROPIC DISTILLATION TOWER: In the azeotropic distillation tower.2 kg of H2O be used per kg of C4H6.7249 x 0.0671 = 8.2 kg of NH3 be used per kg of C4H6.0698 kg In the butadiene purifier NH3 is removed by H2O Let 0.3449 kg AZEOTROPIC DISTILLATION TOWER NH3 : 9. ammonia is used to remove C4H8 Material balance in the azeotropic distillation tower: Let 0.3449 C4H6 : 34.3449 kg kg NH3 : 9. NH3 mixture ∴ H2O used = 0.0027 BUTADIENE PURIFIER: TOTAL : 56.2 = 9.7222 C4H8 : 12.0698 kg TOTAL : 56.7222 C4H6 : 34.2 x 44. 4.6164 x 103 1.3449 C4H6 : 34.7222 kg 2.1 x 103 x 700 ∴ m = 407.7222 NH3 : 9.75 kg Mass of fuel gas required = 407.79 x 1.8134 BUTADIENE : 34.79 HOT FLUID(FUEL GAS) ??? Specific heat.3449 TOTAL : 52.m(kg) COLD FLUID (C4H10) 310.Cp(J/kgK) 1.7222 H2O : 8.8134 NH3 : 9.8805 kg TOTAL : 52. Required data for preheater Required data Mass.1 x 103 Outlet temperature(0C) 650 200 Inlet temperature (0C) 25 900 Temperature difference.Material balance in the butadiene purifier: kg kg BUTADIENE PURIFIER H2O : 8.8805 kg BUTADIENE PRODUCED = 34.∆T (0C) 625 700 ( m x cp x ∆T )cold fluid = ( m x cp x ∆T )hot fluid 310.6164 x 103 x 625 = m x 1. ENERGY BALANCE: PREHEATER: Table.3.75 kg 15 . 79 kg Outlet temp: 6500C FUEL GAS: 407.5.94 x 103 x (T-25) + 32.79 kg Inlet temp: 250C PREHEATER C4H10 (gas): 310.6164 x 103 x (650-25) 16 .187 x 1000 – 310.79 Specific heat.79 x 1.2 Kcal Datum temp: 250C Temperature of products leaving the reactor =? Heat of reaction (∆H)= Σ (mCp ∆T) products + ∆H0R .Σ (mCp ∆T) reactants For adiabatic process: ∆H=0 ∴0 = Σ(mCp ∆T) products + ∆H0R .2 x 4.75 kg Outlet temp: 2000c C4H10 (gas): 310.Σ (mCp ∆T) reactants 0 = 301.6164 x 103 1. Required data for reactor Required data Reactants Products Mass.79 310.79 x 1.75 kg Inlet temp: 9000C REACTOR: Table.Cp(J/kgK) 1.FUEL GAS: 407. m(kg) 310.94 x 103 Inlet temperature of reactant = 6500C Standard heat of reaction ∆H0R = 32. 00 Light ends: 6.79 kg REACTOR C4H10: 310. Required data for quench tower Required data Cold fluid (oil) Mass.1 x 103 x 275 = 310.1 x 103 1.63 C4H6 : 34.79 kg QUENCH TOWER: Table.79 x 1.50C Outlet temp: 545.520C T = 545.22 Total: 310.50C Inlet temp: 6500C kg C4H10 : 248.00 H2 : 3.6164 x 103 x 490.5 m = 426.5 Outlet temperature ( C) 300 55 Temperature difference. m(kg) ??? 310.T – 25 = 520.6164 x 103 Inlet temperature(0C) 25 545. ∆T (0C) 275 490.79 Specific heat.6.67 kg Mass of oil required = 426.67 kg 17 .22 Heavy ends: 6.50C ∴Outlet temperature of products = 545.Cp(J/kgK) 2.72 C4H8 : 12.5 0 Hot fluid(Products from reactor) ( m cp ∆T )cold fluid = ( m cp ∆T )hot fluid m x 2. Oil: 426.∆T (0C) ( m Cp ∆T) cold fluid = (m cp ∆T) hot fluid m X 4.98 kg Water: 79.00 H2 : 3.67 kg Outlet temp: 3000C C4H10: 248.00 H2 : 3.187 X 103 x (85-25) = 310. difference.79 X 1.63 C4H6 : 34.98 kg Mass of water required = 79. Required data for cooler Required data Hot fluid(products from the compressor) cold fluid (water) Mass.72 C4H8: 12.6164 X 103 75 ??? 4.22 Total: 310.00 Light ends: 6.79 kg Oil: 426.50C kg Outlet temp: 550C kg QUENCH TOWER C4H10: 248.187 X 103 25 35 75-35 = 40 85 85-25=60 Outlet temperature(0C) Temp.22 Total: 310.79 kg COOLER: Table.72 C4H8: 12.98 kg Inlet temp: 250C 18 .22 Heavy ends: 6.22 Heavy ends: 6.00 Light ends: 6.79 1. m(Kg) Specific heat.63 C4H6 : 34.7. Cp (J/Kg K) Inlet temperature(0C) 310.6164 X 103 x (75-35) m = 79.67 kg Inlet temp: 250C Inlet temp: 545. 9999 Substituting the above values.79 kg Outlet temp: 350C Water: 79.25 kmoles xF = 0.98 kg Outlet temp: 850C BUTADIENE TOWER: Condenser: V λ = (mCp∆T) cooling medium V= Amount of vapor leaving the tower = D (RD+1) Let RD (reflux ratio) = 2.35 Kg.5 D = amount of distillate = F[(xF – xB) / (xD – xB)] F = 5.14 x (2.9796 xB = 0.79 kg Inlet temp: 750C Products (gas) Mass : 310.COOLER Products (gas) Mass : 310.5 + 1) = 18 kmoles = 295.001 xD = 0. we get D = 5.14 kmoles ∴Amount of vapor = V = 5.6 x 103 J/kg m = mass of cooling medium =? Cp of cooling medium = 3 X 103 J/kgK 19 . λ = 494. λ (J/Kg ) 2321.35 Latent heat. Required data for reboiler Required data Hot fluid Vapor.F (1-q) q = 1(for saturated liquid feed) ύ = V = 295.5 X 10 (ύλ)cold fluid = (mλ)hot fluid 295.Let ∆T = 150C V λ = (mCp∆T) cooling medium 295.26 Kg ύ = vapor flow rate at bottom of the tower.35 X 515 X 103 = 2321.6 X 103 = m X 3 X 103 X 15 m = 3246. ύ (Kg) 295.35 X 494. = V .5 X 103 X m 20 Cold fluid (water) -3 515 X 103 .35 Kg Reboiler: Table.8. 9999 kmoles C4H10 : 4.m = 65.64 C4H8 : 0.9796 21 .21 Heavy ends: 0.64 C4H8 : 0.29 C4H6 : 0.25 HEAVY ENDS: 0.001 5.21 5. F kmoles C4H10 : 4.11 kmoles xF = 0.11 BUTADIENE TOWER DISTILLATE XD = 0.29 C4H6 : 0.14 REBOILER RESIDUE XB = 0.52 Kg mass of heating medium required for reboiler = 65.52 Kg CONDENSER FEED. 35x10 –6 kg/ms Let velocity of flow V = 30 m/s Assume ¾ inch outside diameter tubes of BWG – 16 do = 0.35 x 10 –6)/ 1.of tubes ∆TL = log mean temperature difference = (∆T1 .6 22 .023 (Re)0. Nu = 0.∆T2) / ln[(∆T1/ ∆T2)] UOAO∆TL = (m Cp ∆T) cold fluid 1 / [(1/ho)+(ao/ai)(1/hi)] x 2 x π x ro x L x n x ∆TL = (m Cp ∆T) cold fluid Table.35 x 10-6 = 160204 (>10000) Pr = Cp µ/ K = (1.5)/ 7.4 Re = (di v ρ)/µ = (0. Physical properties data for preheater PHYSICAL PROPERTIES FUEL GAS(SHELL SIDE FLUID) BUTANE(TUBE SIDE FLUID) Cp (J/KgK) ρ (kg/m3) Κ (J/smoC) 1.0191 m di = 0.2.6164 x 10 3 x 7.8 (Pr)0.0198 µ (kg/ms) 2 x 10-5 7.4. ro = outside radius L = Length of the tube n = no.5 0.1 x 103 1.8 0.98 x 10 –2 = 0.0157 m Tube side heat transfer coefficient hi: Using Nusselt equation.0157 x 30 x 2.0339 1.9. DESIGN PREHEATER: UOAO∆TL = (m Cp ∆T) cold fluid = (m Cp ∆T) hot fluid UO = Overall heat transfer coefficient = 1 / [(1/ho)+(ao/ai)(1/hi)] Where ho = shell side heat transfer coefficient hi = tube side heat transfer coefficient Ao = surface area = 2 x π x ro x L x n Where.6164 x 103 2. 7408)] = 111.023 (160204) 0.023 (Re)0.Nu = hi di /K = 0.6)0.3 ho de / K = 0.3 ho = 213. Nu = 0.8 (0.9359 x 10-4 m2 ao = π x do2/4 = 2.8 )/ 2 x 10-5 = 48600 (>10000) Pr = Cp µ/k = 1.9359)(1/344.023 (Re)0.7408 J/sm2 oC Shell side heat transfer coefficient ho: Using Nusselt equation.7408 J/sm2oC ai = π x di2/4 = 1.8 (Pr)0.3551 hi = 273.8 (Pr)0.86 Pt – π x do2/4)/( π x do ) Assume 1-inch triangular pitch de = 0.6489 ho de / K =0.98 x 10 -2/0.4 = 0.8(0.0157 = 344.4 = 273.1 x 103 x 2 x 10-5/ (0.4254 J/sm2oC ∆TL = log mean temperature difference = (∆T1 .6079 J/sm2oC Uo = overall heat transfer coefficient = 1/[(1/ho)+(ao/ai)(1/hi)] ho = 213.6079 J/sm2oC hi = 344.023 (Re)0.3551 x 1.023 (48600)0.018 m Re = de v ρ/µ = (0.8652 x 10-4 m 2 ∴UO = 1/[(1/213.8652/1.∆T2) / ln[(∆T1/ ∆T2)] 23 .8 (Pr)0.3 de = equivalent diameter de for a triangular pitch is given by de = 4 x ( Pt x 0.6489)0.0339) = 0.6079) + (2.018 x 30 x 1. 048 m Outer dia of each tube = ¾ inch = 0.35) = 6047.9727 / 2 = 3930.0157 m No.2755 oC UOAO∆TL = (m Cp ∆T) cold fluid m = mass flow rate of C4H10 = 310.79 kg/min = 5.048 m ∴ n = 1205 ∴ No.0191 m Inner dia of each tube = 0.9727 m3 gas charged / hr Space velocity = 2 m3 gas charged / hr m3 of catalyst ∴Volume of catalyst = 7861.9906 m REACTOR: Volume of gas charged = nRT / P n = 5.35 ∴Volume of bed = 3931/(1 .9906 m DESIGN SUMMARY: Length of each tube = 10 ft = 3. = 0.= [(900-650)-(200-25)] / ln(900-650/200-25) = 210.3584 kmol/min = 321.9864 m3 of catalyst Let porosity ε = 0. of tubes used = 1205 Shell inner diameter = 39 in.0.1797 kg/sec ∆ T = 650 – 25 = 6250C ∴ UO x π x do x L x n x ∆TL = (m x CP x ∆ T)cold Assume length of tube L as 10 ft = 3. = 0.08206 atm m3/kmol K T = 298 K P = 1 atm ∴ Volume of gas charged per hour = 7861.5021 kmol/hr R = 0.6713 m3 of bed Assume D = 3m & L/D = 7 24 . of tubes = 1205 Shell inner diameter = 39 in. 4211 ya* = 0. of transfer units NOY = (yb – ya) / ∆ yL ----------.0273 kmol/s NAPHTHA C4H10 xb = 0.44 = 41 DESIGN SUMMARY: Diameter of each reactor = 3 m Length of each reactor = 21 m No. of reactors required in parallel = 41 ABSORBER: H2 Light ends NAPHTHA xa = 0 ya = 0. ya* = 0 yb = 0. NOY = 11 25 .5 xa = 0.∴ L = 21 m Volume of one reactor = π D2L/ 4 = 148.II y* = 0.0032 A B S O R B E R yb = 0.8421 = 0.5 x 0 = 0 ya = 0.5 x 0.7621 .5 xb = 0.4211 Substituting the above values in equations I and II.8421 C4H6 C4H8 No.7621 C4H10 C4H6 C4H8 H2 Light ends Heavy ends GM = 0. yb* = 0.5 x (equilibrium relationship) ∴ yb* = 0.44 m3 ∴No of reactors required in parallel = 6048 / 148.0032 .I ∆ yL = [(yb – yb*) – (ya – ya*)] / ln {( yb – yb*) / (ya – ya*)} -----. 2 % flooding = {√(0.59 kg / min = 7.0273/2.046 kmol / m3.8460)/π = 1.0396 kmol/m3 = 2.U): Height of transfer unit.9 x 10-3 kg/m.1 x FP x (µL/ρL)^0.046 = 0.1797){√(2.29 kg/m3 Liquid density ρ = 960 kg/m3 µ = 1.1797 kg / sec Liquid flow rate = 427.sec Gm = Molar flow rate / column area Gas flow rate = 310.s ∴ column area = 5.08206 x 308) = 0.79 kg / min = 5.31 m DESIGN SUMMARY: Column diameter = 1.9 m No.2)} x 100 = 53 %.29/960)} = 0.s (LW/VW){√(ρV/ρL)} = (7.T.1266 kg / sec Assuming 38 mm Intalox saddles packing.067 Assume pressure drop of 20 mm H2O/m packing ∴ K4 = 0.9.⇒ No.82 kg/m2.0096 kmol/m2s ∴ Hoy = Gm/ kya = 0.82 = 2.0096/0.9 m ∴ Gm= 0.ρV)} / {13. satisfactory VW = [{K4 x ρV x (ρL .1797 / 1. At flooding K4 = 3.9/3.1266/5.21 m ∴ Zt = Hoy x Noy = 0. of transfer units = 11 HEIGHT OF TRANSFER UNIT (H.8460 = 0. FP = 170 m-1 Gas density ρ (at 350C) = P / RT = 1 / (0. of transfer units = 11 26 .21 x 11 = 2.1}]^(1/2) = 1. HOY = Gm / KYa Let KYa (overall mass transfer coefficient) = 0.8460 m2 = πd2/4 ∴ column diameter = √(4 x 2. 29 C4H6 : 0.11 kmoles RESIDUE XB = 0.9796 HEAVY ENDS: 0.21 B U T T A O DW I E E R N E FEED.Height of each transfer unit = 0.25 xF = 0.31 m BUTADIENE TOWER: DISTILLATE XD = 0.29 C4H6 : 0. F (SATURATED LIQUID) kmoles C4H10 : 4.11 5.21 m Total height of the column = 2.001 27 .14 5.64 C4H8 : 0.21 Heavy ends: 0.9999 kmoles C4H10 : 4.64 C4H8 : 0. intercept of rectifying section operating line = xD/ RD+1 = 0.2857 By Mccabe . No. q= 1 ∴ Slope of feed line = q/q-1 = ∞ y .9999/3.thiele diagram.5 ∴ Equilibrium curve is given by y = α x/(1+[α-1]x) = 2. OF STAGES: Let relative volatility α = 2.5x) For saturated liquid feed. of theoretical stages = 12 .NO.5 = 0.5x/(1+1.1( for reboiler) = 11 28 . XB q -.LINE STRIPPING OPERATING LINE Fig 2 BUTADIENE – HEAVY ENDS SYSTEM EQULIBRIUM CURVE X: MOLE FRACTION OF LIQUID PHASE Y MOLE FRACTION OF VAPOUR PHASE y X 29 RECTIFICATION OPERATING LINE XFXD . 5 m Column diameter = 1.88 = 1.8374 m/s Design for 85% flooding at maximum flow rate Base UV = 0.2 x 8 x 10-2 = 0.6280 m2 ∴Column diameter = √(4 x 1.2 = 1.0996 Base Uf = 0.5 m ρv = 2. of theoretical stages = 11 Tray spacing = 0.2375/1.4327 m2 Taking downcomer area as 12% of total column cross sectional area.2)/2.5 + 1 = 6 m DESIGN SUMMARY: No.6280)/(π) = 1.2 x 60) = 2.8374 = 1.0552 Surface tension = 60 x 10-3 N/m Base K1 = 8 x 10-2 Correction for surface tension: Base K1 = (60/20)0.2375 m3/s Net area required = 2.0996 √(750-2.44 m Column height = 6 m 30 .02 √2.44 m Column height = 10 x 0.518 = 1.COLUMN DIAMETER: FLV bottom = (slope of bottom operating line )√(ρv/ρL) Assume tray spacing as 0.02 FLV bottom = 1.85 x 1.35/(2.2 kg/m3 .4398 m ≈ 1. Base area : 1.5618 m/s Maximum volumetric flow rate: Base : 295.2/750 = 0.4327/0. ρL = 750 kg / m3 Slope of bottom operating line = 1. 52 kg λ steam = 2321.50 = 25oC m steam = 65.5 x 103 J/Kg K µ = 1.0157 m (0.0191 m 31 .REBOILER: Inlet temp. = 750C Vapor Steam: 65.5 x 105 J/kg ho = 8513.52 kg Inlet temp. = 500C REBOILER Heavy ends (lqd) Water: 65.0174 W/moC di = 0.9 x 10-4 kg/ms K = 0. 16 BWG di = 0.6 J/sm2oC Re =di v ρ / µ Assume ¾ inch outside dia. = 500C Outlet temp.52 kg Outlet temp.0157 m do = 0.9 x 10 –4 kg/ms ρ = 39 kg/m3 Re = 0.62 inch) Let v = 30 m/s µ = 1. = 750C UOAO∆TL = (mλ) steam UO = hio ho/ (hio + ho) AO = 2 π ro L n ∆TL = 75 .9 x 10 –4 = 96679 jH = 250 Cp = 1.0157 x 30 x 39 /1. 5 x 103 n = 1. of tubes = 1024 Shell inner diameter = 37 in. Safe plant operation: a) To keep the process variables within known safe operating limits.048 m Outer diameter of each tube = ¾ inch = 0.52/60 = 1.5959 x π x 0.K (Pr)1/3 = 0.048 x 25) ≈ 1024 Shell inner diameter = 37 inch = 0.9398 m 2.0442 hi = (jHK/D) (Pr )1/3 = 703.092 x 2321.9398 m DESIGN SUMMARY: Length of each tube = 10 ft = 3.5 x 103/(541.092 x 2321.5. = 0.39 W/m2oC Clean overall coefficient Uc = hio ho/ (hio + ho) = (8513.0191 m Inner diameter of each tube = 0.5959 W/m2oC UCAO∆TL = (mλ) hot Let L = 10 ft = 3.048 x n x 25 = 1.39) = 541. 32 .0191 x 3.0191 x 3.6 x 578.048 m m = 65.6469 W/m2oC hio = hi x di/do = 578.0157 m No.6 + 578.39)/(8513.092 kg/s 541. PROCESS CONTROL AND INSTRUMENTATION The primary objectives of the designer when specifying instrumentation and control schemes are: 1.5959 x π x 0. Instrumentation: 33 . Product Quality: To maintain the product composition within specified quality standards. Cost: To operate at the lowest production cost. and the reactor dynamics are suitable. the product composition can be monitored continuously and the rector conditions and feed flows controlled automatically to maintain the desired product composition and yield. Production rate: To achieve the desired product output. commensurate with other Objects. REACTOR CONTROL: The schemes used for reactor control depend on the process and the type of reactor.b) To detect dangerous situations as they develop and to provide alarms and automatic shutdown systems. 2. Pressure is usually held constant. If a reliable on-line analyzer is available. More often. Material balance control will be necessary to maintain the correct flow of reactants to the reactor and flow of products and unreacted materials from the reactor. 3. 4. adjusting the controller set points to maintain the product within specification. Reactor temperature will normally be controlled by regulating the flow of heating or cooling medium. based on periodic laboratory analysis. c) To provide interlocks and alarms to prevent dangerous operating procedures. the operator is the final link in the control loop. platinum-platinum 13% rhodium.6. chromel-alumel. Difficulties are sometimes encountered when the liquid deposits on the floor and when the liquid level is foaming or turbulent. iron-constantan. pitted tube. 2. This method is suitable for a wide range of liquids and semi-liquids. Flow rate Measurement: The industrial devices for flow rate estimation are orifice meter. Level Measurement: The flow-shaft type is employed either in open vessels or in pressure vessels. venturi meter. and rotameter. The piping system must be made of special corrosion resistant material meant for corrosive fluids.Temperature Measurement: The temperature-measuring element in a control system for a jacketed tank is generally thermocouple. The five most commonly used thermocouple are copperconstantan. PLANT LAYOUT 34 . platinum-platinum 10% rhodium. 3.EFFULENT TERATMENT RAW MATERIAL STORAGE SCRAP AREA FINISHED BOILER HOUSE AND WATER PLANT EXTENSION AREA PROCESSING AREA SAFETY DEPT C A N T E E N HEALTH CENTER ADMINISTRATIVE OFFICE W O R K S H O P PRODUCT STORAGE SECURITY OFFICE MAIN ROAD Fig. determine the general location of many things. This can be done by consulting Weather Bureau records. or toxic release • Maintenance costs • The number of people required to operate plant • Other operating costs • Construction costs • The cost of the planned future revision or expansion The first thing that should be done is to determine the direction of the prevailing wind. Wind direction will All equipment that may spill flammable materials should be located on the downwind side. PLANT LAYOUT The laying out of a plant is still an art rather than a science. It involves the placing equipment so that the following are minimized: • Damage to persons and property in case of a fire. explosion. Then if a spill occurs 35 . where they could be ignited by an open flame. 36 . This is to minimize the possibility that these facilities will be damaged in case of a major spill. boilers. where there are usually open flames. Items that should be located Upwind of the plant: Plant Offices Electrical substation Central Laboratories Water treatment plant Mechanical and other shops Cooling tower Office building Air Compressors Cafeteria Parking lot Store house Main water pumps Medical Building Warehouses that contain non-hazardous Change house Non-explosive and Fire station Non-flammable materials Boiler house Fired heaters Electrical Power house All ignition sources Items that should be located downwind of the plant Equipments that may spill inflammable materials Blown down tanks Burning Flares Setting ponds For a similar reason the powerhouse. and air supply facilities should be located 250 ft (75 m) from the rest of the plant. and on the upwind side. spark. water pumping.the prevailing winds are not apart to carry any vapors over the plant. or a hot surface. This is especially important for the first two items. and non explosive materials should be located upwind of the plant. For this reason. STORAGE FACILITIES Tank farms and warehouses that contain non-hazardous. Then. mechanical shops and central laboratories. These depend on the characteristics of the material. All of these involve a number of people who need to be protected. or services areas in case of a tank fir. When liquefied petroleum gases are used. public roads and building. the processing area might be damaged. The same reasoning applies to hazardous shipping and receiving areas.Every precaution should be taken to prevent the disruption of utilities. Those that do not fit this category should not be located downwind of the plant. utilities. it may also be wise to separate the boilers and furnaces from the other utilities. storage tanks are located on a hill. Also. They should be located atleast 250 ft (75 m) to the side of any processing. Other facilities that are generally placed upwind of operating units are plant officers. shops and laboratories frequently that are used primarily for quality control are sometimes located in the production area. nonflammable. SPACING OF ITEMS The OSHA has standards for hazardous materials that give the minimum distances between containers and the distances between these items and the property line. Nor should they be located upwind of the plant where. the other utilities will not be damaged. if some of their contents are spilled. the type and size of the container. should fired equipment explode. since this could mean the failure of pumps. whether the tank is above ground or buried and the type 37 . in order to allow the gravity feeding of tank cars. where they could be damaged and possibly destroyed by a major spill in the processing area. agitators. Care must be taken under these circumstances to see that any slop over cannot flow into the processing. and instrumentation. Some authorities suggest this should be 500 ft. Sometimes. the areas for containing spills are always below grade because the gases are denser than air. The gases will accumulate in the low areas will also not be asphyxiated. Often. The grouped layout places all similar pieces of equipment adjacent. this could reduce the number of operations required. This scheme is best for large plants. a combination that best suits the specific situation is used. these would all be placed in the same general area and could be watched by minimum of operators. PLACING OF EQUIPMENT Once a general scheme is decided upon. as well as liquefied petroleum gases. The maximum loss concept must also be considered. unless special precautions are taken. It may be desirable to have two or more processes controlled from one location. it is used mainly for small volume products. The units should be grouped so that the number of operating personnel is minimized. This permits those watching the controllers to quickly investigate and determine the cause of any problems that might arise. the major reason for including the layout in the preliminary plant design is that the transporting equipment and buildings may be sized to make certain that no needed equipment is omitted and that the chosen plant site will be large enough. Some companies place a limit in the maximum loss that can be expected if a fire or explosion occurs. PROCESSING AREA There are two ways of laying out a processing area. only its approximate location can be given. if they were spread out over a wide area. This minimizes the length of transfer lines and therefore reduces the energy needed to transport materials. At this point. Again. instead of using the grouped or flow line layout exclusively. They also prohibit the storage and location of vessels containing flammable and combustible materials inside buildings. The flow line layout uses the train or line system. Specific details are provided for compressed gas equipment containing acetylene-air.of protection provided. since most of the energy transfer equipment has not been sized. This provides for ease of operation and switching from one unit to another. hydrogen-oxygen and nitrous oxide. In industries. more operators might be added. the processing area is divided into unit areas. which locates all the equipment in the order in which it occurs on the flow sheet. if there are 10 batch reactors. In 38 . For instance. enough headroom must be provided so that these can be removed. a floating-head heat exchanger must have enough space so that the tube bundle can be removed from the shell and taken elsewhere for repairs. The roadways along which the crane will travel must have adequate overhead and horizontal clearness. This is to protect both the employees and the equipment. the cost of maintenance exceeds the company’s profit. this may increase construction and operating expenses and the ease of operability. large columns that are field-erected should be located at one end 39 .this case. For instance. The engineer must design to reduce these costs. It can also be a hazard should there be an earthquake. Some pieces of equipment will be elevated to simplify the plant operations. For tanks containing coils and agitators. The superstructure to support on elevated piece of equipment is expensive. The engineer should determine what type of equipment need to be serviced by mobile cranes. For instance. Adequate space must be left around all equipment so that it can be easily serviced and operated. This especially true for solids and slurry feed. However. In some cases. This eliminates the need for some materials-handling equipment. ELEVATION If there is no special reason for elevating equipment it should be placed on the ground level. but away from fired heaters. These pieces of equipment will need to be located on the perimeters of the plant or on a roadway. CONSTRUCTION AND BUILDING Proper placing of equipment can result in large savings during the construction of the plant. fire or explosion. The easiest way to reduce maintenance costs is to allow lots of extra space and to construct everything at ground level for easy access. the control room should be located in a relatively unexposed area near the edge of the processing area. Then it might collapse and destroy the equipment it is supporting as well as that nearby. MAINTENANCE Maintenance costs are very large in the chemical industry. An example of this is the gravity feed of reactors from elevated tanks. PLANNING FOR EXPANSION AND IMPREMENTS Obviously. The extension of bay in one direction can be done inexpensively. RAILROADS. change rooms. It depends on the number of workers employed. All major traffic should be kept away from the processing areas. and tested without interfering with the construction of the rest of the plant. a standard size bay (area in which there are no structural supports) is 20ft x 20ft (6m x 6m).4m) from the center of the railroad track. If. Lavatories. however. no extra space needs to be provided. This means that there should be a road around the perimeter of the site. their location should be indicated on the pilot plan. However. and the size of teach. additional equipment will be required. and requires stronger supports. if they are contemplated. lunch rooms and medical facilities is dictated by OSHA. Research laboratories and office buildings usually not included in the preliminary cost estimate. space should be allocated for it. BUILDING Building with the layout of the plant is the direction as to what types of buildings are to be construction. Buildings and loading docks should be set back 8 ft (2. 40 . welded. For safety there should be two ways to reach every location. No road should be dead-end. and for maintenance equipment. The net result will be an increase in these initial costs of construction and some increase in material transfer costs. Spurs and switches should be laid out with a 100 ft (30m) radius. if the equipment has been over designed to meet the anticipated future expansion. Under normal conditions a 20-ft (6m) span does not need any center supports.of the site so that they can be built. ROADWAY AND PIPE RACKS The main purpose of railroads is to provide an inexpensive means for obtaining raw materials and for shipping products. When laying out buildings. Roads are used not only for these purposes but to provide access for fire fighting equipment and other emergency vehicles. This means that they should be close to raw materials and or/ product storage. This only increases the amount of steel in the long girders. because the transfer lines will be longer. PROCESSING BUILDINGS Quality control laboratories are necessary part of any plant. The fixed capital investment in the process area. either this operation will be performed in a separate building. WAREHOUSE The engineer must decide whether warehouses should be at ground level or at dock level. The capital investment in the auxillary services. Adequate space must be proved in them for performing all tests. IW. C. The capital investment as working capital.. This is the investment in all processing equipment within the processing area. FIXED CAPITAL INVESTMENT IN THE PROCESS AREA. 2. 41 . Packaging equipment generally must be in enclosed buildings. B. IF. It is usually difficult to justify the added expense of a dock-high warehouse. COST ESTIMATION ESTIMATION OF THE TOTAL CAPITAL INVESTMENT: The total capital investment “I” involves the following: A. IA. i. and must be included in all cost estimates. IF. If the material being packaged is hazardous. The latter facilitates loading trains and trucks.e.7. I = IF + IA + IW A. and is often located at one end of the warehouse. or a firewall will separate it from any processing or storage areas. but costs 15-20 percent more than one placed on the ground. and for cleaning and storing laboratory sampling and testing containers. 6 x 106 1.17 x 106 3.4 x 106 2 Reactor 41 2. Delivered cost of major equipment S.2 x 108 lakhs TOTAL Table.11.10.No Items Direct cost factor 1 Delivered cost of major equipments 100 2 Equipment installation 15 3 Insulation 15 4 Instrumentation 15 5 Piping 75 6 Land & building 30 7 Foundation 10 8 Electrical 15 9 Clean up 5 Total direct cost factor 42 280 .066 x 108 3 Heat exchanger 5 7 x 105 35 x 105 4 Distillation column 3 8 x 105 24 x 105 5 Absorption column 1 6 x 105 6 x 105 6 Stripper 2 4 x 105 8 x 105 7 Mixer settler 1 5 x 105 5 x 105 8 Pump 1 10000 10000 9 Ejector 1 10000 10000 10 Compressor 1 10000 10000 11 Miscellaneous 3.17 x 106 1.4 x 106 2. Direct cost factor S.Fixed Capital Investment In The Process Area. Equipment Units Cost in lakhs/unit Cost in lakhs 1 Furnace 1 2. If = Direct Plant Cost + Indirect Plant Cost The approximate delivered cost of major equipment used in the proposed Butadiene manufacturing plant are furnished below: Table.No. IF = Direct plant cost + Indirect plant cost = 3. IA.36 x 108 * 56) / 100 = 1. Such items as steam generators.8816 x 108 lakhs Fixed capital investment in the process area. Indirect cost factor S. 43 .36 x 108 + 1.8816 x 108 = 5.Direct plant cost = (Delivered cost of major equipments) × (Total direct cost factor) / 100 Direct plant cost = (1. fuel stations and fire protection facilities are commonly stationed outside the process area and serve the system under consideration. 30 2 Engineering fee 13 3 Contingency 13 Total indirect cost factor 56 Indirect plant cost = (Direct plant cost)(Total indirect cost factor) / 100 = (3.No.2 x 108 * 280) / 100 = 3.2416 x 108 lakhs B.12. The capital investment in the auxiliary services. Item Indirect cost factor 1 Overhead contractor etc.36 x 108 lakhs Table. Table.13. Auxillary services cost factor S.No. Items Auxillary services cost factor 1 Auxillary buildings 5 2 Water supply 2 3 Electric Main Sub station 4 Process waste system 1 5 Raw material storage 1 6 Fire protection system 0.7 7 Roads 0.5 8 Sanitary and waste disposal 0.2 9 Communication 0.2 10 Yard and fence lighting 0.2 Total 12.3 1.5 Capital investment in the auxillary services = (Fixed capital investment in the process area)( Auxillary services cost factor) / 100 = (5.2416 x 108 * 12.3) / 100 = 6.4471 x 107 lakhs Installed cost= Fixed capital investment in the process area + Capital investment in the auxillary services = 5.2416 x 108 + 6.4471 x 107 = 5.8863 x 108 lakhs 44 C. The capital investment as working capital, IW. This is the capital invested in the form of cash to meet day-to-day operational expenses, inventories of raw materials and products. The working capital may be assumed as 15% of the total capital investment made in the plant ( I ). Capital investment as working capital, IW = (5.8863 x 108 * 15) / 85 = 1.0387 x 108 lakhs Total capital investment, I = IF+ IA+ IW = 5.2416 x 108 + 6.4471 x 107 + 1.0387 x 108 = 6.9250 x 108 lakhs ESTIMATION OF MANUFACTURING COST The manufacturing cost may be divided into three items, as follows: A. Cost Proportional to total investment B. Cost proportional to production rate C. Cost proportional to labour requirement A. COST PROPORTIONAL TO TOTAL INVESTMENT This includes the factors, which are independent of production rate and proportional to the fixed investment such as - Maintenance-labour and material - Property taxes - Insurance - Safety expenses - Protection, security and first aid 45 - General services, laboratory, roads, etc. - Administrative services For this purpose we shall charge 15% of the installed cost of the plant = (Installed cost * 15) / 100 = (5.8863 x 108 * 15) / 100 = 8.8294 x 107 lakhs B. COST PROPORTIONAL TO PRODUCTION RATE The factors proportional to production rate are - Raw material costs - Utilities cost – power, fuel, water. Steam, etc. - Maintenance cost - Chemical, warehouse, shipping expenses Assuming that the cost proportional to production rate is nearly 60% of total capital investment, Cost proportional to production rate = (Total capital investment * 60) / 100 = (6.9250 x 108 * .6) = 4.1550 x 108 lakhs C. COST PROPORTIONAL TO LABOUR REQUIREMENT The cost proportional to labour requirement might amount to 10% of total manufacturing cost. Cost proportional to labour requirement=(8.8294x107+4.155x108)(0.1)/(0.9) 46 5978 x 107 lakhs Therefore.15) / (1+0.8294x107+4.155x108+5.8863 x 108 * .45/kg Production rate = 50 TPD Total sales income = 45 x 50 x 1000 x 330 = 7.5978x107) = 5.15)15-1 = 1.425 x 108 lakhs PROFITABILITY ANALYSIS A.2371 x 107 lakhs 47 .5978 x 108 lakhs SALES PRICE OF PRODUCT Market price of Butadiene = Rs. manufacturing cost = (8.= 5. DEPRECIATION According to sinking fund method: R = (V-VS) I / (1+ I)n R = Uniform annual payments made at the end of each year V = Installed cost of the plant VS = Salvage value of the plant after n years N = life period (assumed to be 15 years) I = Annual interest rate (taken as 15%) R = (5. Net profit = Gross profit – Depreciation .1.8863 x 108 = 16.7262 x 107 lakhs D. Tax rate is assumed to be 40%.36908 years 2.B.7262 x 107+ 1.(Gross profit*Tax rate) = 1.7262 x 107) / 5.manufacturing cost = 7. PROCESS SAFETY Introduction: 48 .4) = 9.8272 x 108 . PAYOUT PERIOD Payout period = Depreciable fixed investment / ((profit)+(depreciation)) = 5.5978 x 108 = 1. NET PROFIT It is defined as the annual return on the investment made after deducting depreciation and taxes.2371 x 107) = 5. GROSS PROFIT Gross profit = Total sales income .5. ANNUAL RATE OF RETURN Rate of return = (100*Net profit/Installed cost) = (100*9.8863 x 108 / (9.8272 x 108 lakhs C.8.5235% E.8272 x 108 *0.425 x 108 .(1.2371 x 107 . In recent years there has been an increased emphasis on process safety as a result of number of serious accidents. Local and national governments are taking a hard look at safety in industry as a whole and the chemical industry in particular. This is due in part to the worldwide attention to issues in the chemical industry brought on by several dramatic accidents involving gas releases. which causes or is likely to cause an injury. the public often associates chemical industry with environmental and safety problems. major explosions and several environmental accidents. it will be seen that the occurrence of an injury is the culmination of a series of events or circumstances that invariably occur in a fused and logical order. There has been an increasing amount of government regulations. 49 . Faults of persons are inherited from the environment and reasons for the faults are: Improper attitude Lack of knowledge or skill Physical unsuitability Improper mechanical or physical environment Accident prevention: Form the foregoing. Public awareness and of these and other accidents has provided a driving force for industry to improve its safety record. Industrial accidents: An accident has been defined as an unplanned or unexpected event. It is vital for the future of the chemical industry that process safety has a higher priority in the design and operation of chemical process facilities. For many reasons. An accident occurs as a result of unsafe actions or exposure to an unsafe environment. Unsafe actions or unsafe mechanical or physical conditions exist only because of faults of a particular person. even though previous events or circumstances in the sequence are unfavorable. Using unsafe equipment. Working on moving or dangerous equipment. The most important point is that unsafe conditions or actions are the immediate cause of accidents. Operating or working at unsafe speed. Prevent unsafe action being committed.Knowledge of the factors in the accident sequence guides and assists in selecting the point of attack in prevention work. mixing etc. The supervision and management can control the actions of employed persons and so prevent unsafe acts and also guard or remove unsafe conditions. Unsafe conditions –examples: Operating without securing. The four factors that converge to cause accidents are: Personal factor Hazard factor Unsafe factor Proximate casual factor The solution under the four factors would also lead to two steps. Prevent unsafe mechanical or physical conditions. It permits simplification without sacrifice of effectiveness. These are planning and organizing to 1. Unsafe mechanical and physical conditions-examples 50 . placing. Unsafe loading. Making safety devices inoperative. warning etc. Taking unsafe positions or posture. 2. Instruction. Persuasion. Industrial ventilation and lighting The main functions of ventilation in an industry are: To prevent harmful concentration of aerosols. Inadequately guarded. Ventilation should aim at Keeping the air temperature of the workroom low enough to enable 51 . delayed etc). To maintain reasonable condition of comfort for operators at workplace. planning etc. Inadequate or improperly distributed ventilation. Unsafe dress or apparel. The most important means of accident prevention are: Engineering revision. Unsafe method. process. Unguarded. It maintains the body heat balance and to provide reasonable conditions of comfort. Personal adjustment. Defective condition (rough. Appeal. Hazardous arrangement or process. Discipline. Unsafe design or construction. which operate to induce natural ventilation in building. Duration and type of occupants and their activities. Types of natural ventilation: 1. 2. The operators of the ventilating system. Cross ventilation. 3. 52 . Natural ventilation 2. Heat gains from sun. 3. hot manufacturing. Cool type roof ventilation.1. body heat to be dissipated by convection. preventing excessive humidity so as to assist body heat loss by evaporation. 4. The amount of ventilation generally depends on the following factors: 1. 5. 2. Mechanical ventilation Natural ventilation Forces. are due to: Pressures exerted by outside wind The temperature differences of the air within and without the building. Temperature conditions. Types of ventilation 1. Roofed ventilation. 2. Size and type of room or building and its usage. 3. regulating the rate of air movement so that loss of body heat by convection is facilitated. The degree of protection. Make sure that the employees use and maintain these correctly. the employers are required to provide it. Once it is decided to use personal protective devices. two criteria should be used: 1. Free of cost and also should be responsible to ensure its usage maintenance and renewal. The ease with which it may be used. Respiratory devices 2. 2. Protective devices are divided into two groups: 1. For selection of device. we must select the proper type of device. Non-respiratory devices Safety appliances: 53 .Mechanical ventilation It is brought out by either one or both of the following two methods: Ventilation through windows or other openings owing to the suction created by the exhaust of air Positive ventilation by means of a fan or blower Types of mechanical ventilation: Exhaust ventilation Combined plenum and extraction systems Mechanical roof ventilators. Personal protective devices: Protective devices are required by regulation. No worker will be allowed to enter any plant without a helmet. Special goggles must be worn for gas welding and grinding operations. In spite of safety appliances. Hand gloves: While operating any valve or equipment and also while executing any maintenance work including electrical maintenance work. 54 . Plastic aprons: This along with the hood gives protection to the operation and maintenance staff while handling dangerous acids and other hazardous chemicals particularly when there is possible leakage. the employees should wear appropriate type of safety gloves. Safety shoes: All the employees working inside a factory should wear safety shoes and gumboots should be used while handling acids and alkalis. which can cause a lot of irritation and in the long run painful and incurable diseases. Safety goggles: The goggles must be worn while entering the process areas. Dust mask: While working in a dusty atmosphere. the company’s medical center is equipped to meet any emergency and any employee coming in contact with acids or any hazardous chemicals must be treated at the medical center immediately. the employees must wear dust masks to prevent dust and fumes from entering the sensitive respiratory organs.Helmets: Every employee inside the factory should always wear the safety helmet to avoid head injuries. Nickel alloy steels are said to be satisfactory provided that the catalyst is not calcium nickel phosphate. High chrome alloy steels are used for the construction of catalyst support grids in Houdry plant. but brass. The internal surfaces of Houdry reactor are alternatively exposed to high temperature hydrocarbons and air atmospheres. MATERIALS OF CONSTRUCTION Generally carbon steel is suitable for most plant equipment processing butadiene or similar hydrocarbons. They are deposited at the bottom of butadiene containers. Chrome alloys are (4 to 30%) are however. carbon steel is regarded suitable.9. Special construction materials may be essential in certain other circumstances. inhibitors. the surfaces are exposed to high temperatures and steam. For example. An aqueous sodium nitrite solution is also used as an antioxidant in the production of butadiene. claimed to give good service. Nickel steels are said also to be responsible for coke formation in n-butane dehydrogenations. Brass or copper should be avoided because of the possible formation of explosive acetylides from traces of acetylene. like TBC (p-tert-butylpyrocatechol) or TBK (2. Refractory linings are essential. This reaction is dependent 55 .10. Butadiene forms dangerous polymeric peroxides with oxygen. which are viscous liquids sparingly soluble in liquid butadiene. In purification plants. consequently carbon steels are not suitable. STORAGE. In addition. Butadiene can polymerize during its production. STABILIZATION. Heavy carbon deposition is possible when this catalyst is used with nickel alloys. Carbon steel is suitable in cuprous ammonium acetate extraction plant. copper or bronze alloys must be avoided. 2. Hence. handling of butadiene requires complete exclusion of oxygen. AND TRANSPORTATION Stabilization involves protection against the action of oxygen and against polymerization. are added because they are especially effective at scavenging radicals. They also prevent a spontaneous polymerization of butadiene and can easily be removed by washing with aqueous sodium hydroxide.2. Oxy halo dehydrogenation processes can give very high corrosive conditions. in an nbutene hydrogenation vessel. it can dimerize to vinylcyclohexene.6-di-tert-butyl-p-cresol). storage and transportation in three different ways: First. Liquefied butadiene is stored at normal temperatures in liquid-gas containers or. granular. 2. nose. Exposure studies have been made using mice and rats. initiated by oxygen. The formation of Popcorn in closed areas can lead to pressures of > 1000 bar. the so-called Popcorn.on time and temperature and can be stopped by adding a potassium cyanide solution to butadiene. Secondly. railroad tank wagons. and in ships. and rust. and very hard polymer.3-butadiene may vary individually. and short exposures to higher temperatures reduce this polymerization. Short-term exposure to high concentrations of butadiene may cause irritation to the eyes.11. SAFETY AND TOXICOLOGY Butadiene has been used widely in producing many important industrial polymers and other products. and throat. temperatures of 40C and pressure less containers are required. but only a weak carcinogen in the rat. HEALTH. exclusion of oxygen. It is transported at normal temperatures and raised pressures in tankers. The interpretations have focused on differences in toxification rates and detoxification metabolisms as causative factors. butadiene can polymerize. Long-term physiological reactions to 1. Dermatitis and frostbite may result. today. causing the bursting of off-stream tubes or containers. It forms preferentially in off-stream tubes. for safety reasons at a temperature of 40C in almost pressureless containers. butadiene can polymerize under the influence of oxygen and high temperatures. low temperatures. Butadiene was found to be a potent carcinogen in the mouse. like TBC. These experiments have demonstrated species differences in butadiene toxicity and carcinogenicity. It can be prevented by the addition of TBC and by the careful elimination of all Popcorn seeds. hence. must be kept moist during its removal. opalescent. Antioxidants. high temperatures. to give rubber-like polymers (fouling). to give a glassy. 56 . Popcorn is spontaneously inflammable in air and. especially during its manufacture. Especially in ships. Thirdly. Its growth is favored when Popcorn seeds are present in the plant. Exposure limits Country Exposure Limit Belgium 10 ppm Germany 5 ppm before polymerization 15ppm after polymerization Italy 10 ppm (predicted) Japan 10 ppm (voluntary adoption) Latin America 1 ppm (predicted) The Netherlands 50 ppm United Kingdom 10 ppm United States 10ppm (ACGIH. Also with the major advancements like production of a new elastomer system based on carboxy-terminated butadiene acrylonitrile polymers (CBTN) as an alternative to urethane technology and its wide applications. Table. some-times preceded by excitation and hyperventilation. This project has analyzed the salient features of the process of manufacture of Butadiene. 1982) 10ppm for 15 min (OSHA 1990) 2ppm 8-h time weighted average (OSHA 1990) CONCLUSION Butadiene is one of the most important chemicals.Butadiene is of low acute toxicity. cost estimation and project feasibility. 57 .14. butadiene has become one of the most widely used chemicals in the world. It has also dealt with the various design aspects of the important equipments. Like some other hydrocarbons butadiene causes narcotic effects after inhalation of high concentrations. .A.Q.E.R. Treybal. (1977) ‘Chemical Engineering’.G.K.R. Mccabe.O. Smith.J.P. Kern.REFERENCES 1. (1993) ‘Outlines of Chemical Technology’.S. Austin.. ‘Encyclopedia of Chemical Engineering’ 13. Fifth edition. Vol. Wiley 7.O. (1984) ‘Shreve’s Chemical Process Industries’. Perry.J.. Green. Tata Mcgraw-Hill 3.L.P.D.D.. New York 4.M. (1985) ‘Process Heat Transfer’. Second edition 11. John Wiley and Asia Publishing. Second edition. Peter and Timmerhaus. Affiliated East-West Press 6.. Dryden.E. 6.J. ‘Encyclopedia of Chemical Engineering’ 10. Mcgraw-Hill edition 12. Bhatt. Mcgraw-Hill Kogukosha 16. Mcketta.. John Wiley. 8. Pergamon Press 5. (1980)‘Mass Transfer Operations’.. Mcgraw-Hill. and Ragatz. Mcgraw-Hill International Book Co.W.T. ‘Industrial Chemistry Handbook’ 58 ... Richardson. Revised edition 9.C. (1978) ‘Industrial Instrumentation’. (1986) ‘Process Systems Analysis and Control’.. (1972) ‘Chemical Reaction Engineering’.M. Mcgraw-Hill edition 14.. Mcgraw-Hill... Coughnowr and Koppel.D. Eckman. Watson. (1997) ‘Perry’s Chemical Engineers’ Handbook’.A.M. Ullman. and Harriot.B..R. Coulson.W. (1976) ‘Stoichiometry’. Vora..C.L.H. Kirk and Othmer.... Levenspiel.F. Hougen. (1993) ‘Unit Operations in Chemical Engineering’. Singapore 2. (1970) ‘Chemical Process Principles Part-1’. ‘Plant design and Economics for Chemical Engineers’ 15.