Project Report of Production of Butadiene from Butane Submitted to the M.S. University of Baroda in partial fulfillment of the requirements of Bachelor of Engineering in Chemical Engineering

Production of Butadiene from Butane

By

Sudhanshu S Soman

Guided by,Dr. R.A. SENGUPTA

CHEMICAL ENGINEERING DEPARTMENTFACULTY OF TECHNOLOGY & ENGINEERINGTHE MAHARAJA SAYAJIRAO UNIVERSITY OF BARODA CHEMICAL ENGINEERING DEPARTMENTFACULTY OF TECHNOLOGY & ENGINEERINGM.S.UNIVERSITYBARODA2012-2013

CERTIFICATE

This is to certify that this project report is a bonafide record of the work done by Mr. SUDHANSHU S SOMAN (Exam No. ________) of B.E.-IV Chemical Engineering. He has successfully completed his Seminar on Photonic Materials and Applications in the year 2012-2013 under my guidance and supervision. His report is now ready for assessment.

Project Guide : Professor (Dr.) Ranjan Sengupta Dr. Bina R Sengupta Head Of Chemical Engg. Dept.

Date: _________ Date: ________ Production of Butadiene from Butane

CHEMICAL ENGINEERING DEPARTMENTFACULTY OF TECHNOLOGY & ENGINEERINGM.S.UNIVERSITYBARODA2012-2013

Prepared By : Sudhanshu S SomanGuided By : Professor (Dr.) Ranjan Sengupta CONTENTS :CHAPTER 1: INTRODUCTION1.1 Butadiene Introduction...4CHAPTER 2 : LITERATURE REVIEW 2.1 Feed Properties82.2 Product Selection92.3 Market Scenario....132.4 Butadiene Manufacturing Process Information.152.5 Conceptual Design Analysis..212.6 Input Output Structure.252.7 Recycle / Reactor Synthesis...252.8 Separation Structure.29CHAPTER 3 : PROCESS DESCRIPTION3.1 Preprocess Purification Deisobutanizer...333.2 Dehydrogenation Section...343.3 Purification Section36CHAPTER 4 : MATERIAL & ENERGY BALANCE4.1 Distillation Unit..404.2 Non-Oxidative Dehydrogenation Reactor...414.3 Oxidative Dehydrogenation Reactor424.4 Distillation Unit Energy Balance..444.5 Non-Oxidative Dehydrogenation Reactor Energy Balance.......464.6 Oxidative Dehydrogenation Reactor Energy Balance47

CHAPTER 5 : DESIGN OF EUIPMENTS5.1 Design of Distillation Column...495.2 Design of Heat Exchanger.585.3 Design of Reactor...65CHAPTER 6 : PLANT LAYOUT 6.1 Factors in Choosing a Suitable Plant Location...776.2 Plant Layout Consideration Factors806.3 Site Layout..82CHAPTER 7 : COST ESTIMATION7.1 Direct Cost..907.2 Total Product Cost.937.3 Spreadsheet For Estimation of TCI.977.4 Spreadsheet For Estimation of TPC....987.5 Profitability Analysis.99CHAPTER 8 : MATERIAL SAFETY AND CHEMICAL HAZARD8.1 Inherent Safety Aspect..1018.2 Distillation Column HAZOP Analysis...1058.3 Non-Oxidative Dehydrogenation Reactor HAZOP Analysis...106CONCLUSIONREFERENCESAPPENDICES

CHAPTER 1 : INTRODUCTION

INTRODUCTION1.1 Butadiene Introduction :Butadiene is a flammable, colorless gas with a mild aromatic odor and it is highly reactive. Its physical Description - Colorless gas that has a mild gasoline-like odor. Its molecular weight is 54.1 & boiling/melting point 24F / -164F. Butadiene is soluble in alcohol and ether, insoluble in water and polymerizes readily, particularly if oxygen is present.One major use of butadiene has been in the making of synthetic rubber (styrene-butadiene and nitrile butadiene rubbers, to a large extent, CIS-polybutadiene is also an extender and substitute for rubber, and polymerizations transpolybutadiene is a type of rubber with unusual properties). Butadiene is also used extensively for various polymerizations for plastics manufacturing.

1,3-Butadiene was discovered in the nineteenth century and its use in the development of rubber-like polymers was explored during the early 1900s (Grub and Loser 2005; Sun and Wristers 2002). Large volume production of 1,3-butadiene in the United States began during World War II. The Russian chemist Sergei Vasilyevich Lebedev was the first to polymerize butadiene in 1910.[19][20] In 1926 he invented a process for manufacturing butadiene from ethanol, and in 1928, developed a method for producing polybutadiene using sodium as a catalyst.There are two sources of butadiene in world: Extractive distillation from Crude C4 stream produced as a co-product of ethylene production, and on-purpose production by dehydrogenation o n-Butane or n-Butenes. Leading licensors of technology for Butadiene are Shell, BASF and Nippon-Zeon.

BASF, Borealis, Equistar Chemical, ExxonMobil, Ineous, Polimeri Europa, Reliance Industries, Repsol YPF, Sabic, Shanghai Petrochemical, Shell, Sinopec are the leading producers of Butadiene.

The demand on the global butadiene market is indicating reasonable growth it is also expected that it will move upwards by 2-2.5% annually in the coming 5-6 years. The butadiene markets in the developed countries are not considered as considerable contributors to the demand growth the market has already reached its saturation point. However the developing BRIC countries make up the major driver behind the butadiene industry activity.

The global capacity of Butadiene was 12 MMT in 2011 against demand of 9 MMT. The capacity is expected to increase to 14 MMT in 2016 with demand reaching 12 MMT. In India total Butadiene capacity is expected to reach 528 KTA by 2016-17 and IOC has planned capacity expansion to 138 KTA by 2016-17 followed by OPAL 95 KTA

Up to 50% of the produced volume of butadiene is taken up by SBR and polybutadiene. These applications are forecast to lead the demand in the near future as they are both set to lavishly develop through 2017.

Butadiene is used to manufacture rubber for tires, hoses, gaskets, paints and adhesives. It is also used in the production of nylon clothing, carpets and engineering plastic parts.Table : Properties of 1, 3 Butadiene (Air Liquide MSDS, 2005)

PROPERTIESVALUES

Physical state at 20 CLiquefied gas.

ColourColorless gas.

OdourPoor warning properties at low concentrations.

Molecular weight54

Melting point [C]-109

Boiling point [C]-4.5

Critical temperature [C]152

Vapour pressure, 20C2.4 bar

Relative density, gas (air=1)1.9

Relative density, liquid (water=1)0.65

Solubility in water [mg/l]1025

Flammability range [vol% in air]1.4 to16.3

Auto-ignition temperature [C]415

Other data

Gas/vapour heavier than air. May accumulate in confined spaces, particularly at or below ground level

CHAPTER 2 : LITERATURE REVIEW

LITERATURE REVIEW2.1 Feed Properties :The main feed supplied to the plant is crude C4 which mainly consisted of butanes (also called normal butane or n-butane). According to Wikipedia (2007), butane is the unbranched alkane with four carbon atoms, CH3CH2CH2CH3. Butane is also used as a collective term for n-butane together with its only other isomer, isobutane (also called methylpropane), CH (CH3)3. Figure shows the molecular structure of n-butane and isobutane. Figure : Molecular structure of (a) n-butane and (b) isobutane Butanes are highly flammable, colorless, easily liquefied gases. The properties of butane as feed are given in Table.Table : Properties of Butane (Wikipedia, 2007)PROPERTIESVALUES

Molecular formulaC4H10

Molar mass58.08 g/mol

AppearanceColorless gas

Density 2.52 g/l, gas (15 C, 1 atm)

Phase0.584 g/cm3, liquid

Liquid Solubility in water6.1 mg/100 ml (20 C)

Melting point 138 C

Boiling point 0.5 C

2.2 Product Selection :The team has been assigned by BCD Chemicals to design a plant which uses butane as the main feed and to select the most economical butane derivative product. There are four potential products discussed by the team; 1. Polyisobutylene2. Maleic Anhydride3. Propylene Oxide4. ButadieneAccording to Peters and Timmerhaus (1991), before any detailed work is done on the design, the technical and economic factors of the proposed process should be examined. A feasibility survey will give an indication of the probable success of the project and will also shows what additional information is necessary to make a complete evaluation.2.2.1 Polyisobutylene :Polyisobutylene, also known as Butyl rubber (C4H8)n is a synthetic rubber, a homopolymer of 2-methyl-1-propene. Polyisobutylene is produced by polymerization of about 98% of isobutylene with about 2% of isoprene. Structurally, polyisobutylene resembles polypropylene, having two methyl groups substituted on every other carbon atom. It has excellent impermeability, and the long polyisobutylene segments of its polymer chains give it good flex properties. Polyisobutylene is a colorless to light yellow viscoelastic material. It is generally odorless and tasteless, though it may exhibit a slight characteristic odor (Wikipedia, 2007).The formula is for polyisobutylene is shown in Figure :

Figure : PolyisobutyleneApplication: Polyisobutylene is used in making adhesives, agricultural chemicals, fiber optic compounds, cling film, electrical fluids, lubricants (2 cycle engine oil), paper and pulp, personal care products, pigment concentrates, for rubber and polymer modification, as a gasoline/diesel fuel additive, and even in chewing gum. The first major application of butyl rubber was tire inner tubes. This remains an important segment of its market even today.Strengths and WeaknessesOne of the strengths of polyisobutylene is the increasing market demand of this product. The region range for polyisobutlyne consimer is wide too. However, the production process is very extreme since the feed needed to be heated up to 600oC for dehydrogenation process then later coolded to -40oC for polymerization. The capital and operting cost of the process will be very high.2.2.2 Maleic Anhydride :Maleic anhydride (cis-butenedioic anhydride, toxilic anhydride, dihydro-2,5-dioxofuran) is an organic compound with the formula C4H2O3 (C=OCH=CHC=O2).

Figure : Maleic AnhydrideIn its pure state, it is a colorless or white solid with an acrid odor. Maleic anhydride is refined pure white crystal at room temperature and transformed to colorless liquid at heating. It is sublimate.Application: Maleic anhydride is used as a chemical intermediate in the synthesis of fumaric and tartaric acid, certain agricultural chemicals, resins in numerous products, dye intermediates, and pharmaceuticals. It is also used as a co-monomer for unsaturated polyester resins, an ingredient in bonding agents used to manufacture plywood, a corrosion inhibitor, and a preservative in oils and fats.Strengths and WeaknessesMaleic anhydride market is very stable since it has been established for very long. However, it is very hard for a new player to perform in the competitive environment. The market demand of maleic anhydride is also slowed down recently.2.2.3 Propylene Oxide [3]Propylene oxide is a versatile chemical intermediate used in a wide range of industrial and commercial products. By volume, it is among the top 50 chemicals produced in the world.Application:Propylene oxide is a highly reactive chemical used as an intermediate for the production of numerous commercial materials. It reacts readily with compounds containing active hydrogen atoms, such as alcohols, amines, and acids. Therefore, propylene oxide is used worldwide to produce such versatile products as: Polyether polyols (polyglycol ethers) Propylene glycols Propylene glycol ethersPolyether polyols are one of the main components in polyurethane systems and are used in many consumer applications, such as rigid foam insulation and flexible foam seat cushions. Polyether polyols make up the largest share of propylene oxide usage, between 60% and 70% of the total volume. Propylene glycol consumes another 20% of the total volume while propylene-based glycol ethers comprise about 5%. The remaining share goes into other propoxylated or specialty organic compounds. Also, other products made using propylene oxide are: Flame retardants Modified carbohydrates (starches) Synthetic lubricants Oil field drilling chemicals Textile surfactantsStrengths and WeaknessesAlthougth the market demand is growing, the production process of propylene oxide is very complicated. Since the main reactant of for propylene oxide production is propylene, and the feed only consisted of very small portion of propylene, additional process is required to converted n-butane or isbutane to propylene. Hence, the process might not be economy feasible.2.2.4 Butadiene :1,3-Butadiene is a simple conjugated diene. It is an important industrial chemical used as a monomer in the production of synthetic rubber. When the word butadiene is used, most of the time it refers to 1,3-butadiene.

Figure : ButadieneApplication:The largest single use for butadiene is in the production of styrene- butadiene rubber (SBR) which in turn is principally used in the manufacture of tires. According to Huntsman (2006), about half of all butadiene consumption in the United States is for styrene butadiene rubber (SBR) and polybutadiene (PB), the primary feed to tires manufacturing. Approximately 14% of the butadiene consumed in the US goes into the production of nylon 6, 6 which is used in making carpet. About 13 % of the butadiene is used in the manufacture of styrene butadiene latex (SBL) which is further processed into products such as adhesives and carpet backing. Another important use for butadiene is the production of acrylonitrile butadiene styrene (ABS) plastic which is used for pipe, automotive components and housings for electronic equipment such as telephones and computers.2.3 Market :According to CMAI (2007), global butadiene demand is expected to grow at just under 3.5%/year through 2012, slightly above the average of 3.2%/year growth of the past five years. Demand in India will be the largest, growing nearly 15%/year for the next five years. Demand in Asia is expected to exceed 5%/year, although demand in some countries, primarily China, will be at more than 10%, analysts say. Demand in North America and Western Europe is expected to rise at less than 1%.Most of the capacity will be added in Asia, particularly China, which will account for nearly 75% of new capacity, added before 2012. Operating rates in Asia are expected to be strong at 85%-90%, while operating rates in Europe will be highest, at about 90%, analysts say. Operating rates in North America are expected to hover in the 70% range, they say. Table 2.3 shows the butadiene producer and production rate in Asia. Notice that in Malaysia, there is only 100,000 mt /year production totally.

CountryProducersProduction Rate(in thousands of MT./year)

ChinaYangzi Petrochemical185

CNOOC Shell Petrochemicals4155

Maoming Petrochemical150

Jilin Chemical140

Qilu Petrochemical130

Lanzhou Petrochemical120

Shanghai Petrochemical120

Yanshan Petrochemical113

Others395

Total1508

IndiaReliance Industries150

Others172

Total322

JapanJapan Synthetic Rubber268

Chiba Butadiene177

Nippon Zeon150

Okayama Butadiene140

Tobu Butadiene130

Tonen General105

Nippon Petrochemicals70

Total1040

KoreaYeochon Naphtha Cracking Centre218

Korea Kumho Petrochemical205

LG Chemical145

Lotte Daesan Petrochemical109

Samsung Petrochemicals99

LG Daesan Petrochemical98

SK Corp.72

SK Energy72

Total1018

MalaysiaTitan Petchem100

Total100

Singapore60

Total60

TaiwanFormosa Petrochemical373

Chinese Petroleum173

Total546

ThailandBangkok Synthetics140

IRPC565

Total205

Average:149.96875

2.4 Butadiene Manufacturing Process Information :Butadiene is produced commercially by three processes:

1) Steam Cracking of Paraffinic Hydrocarbons: In this process, butadiene is a co- product in the manufacture of ethylene (the ethylene co-product process).2) Catalytic Dehydrogenation of n-Butane and n-Butene (the Houdry process).3) Oxidative Dehydrogenation of n-Butene (the Oxo-D or O-X-D process).

Each of these processes produces a stream commonly referred to as crude butadiene that is rich in 1,3-butadiene.

2.4.1 Butadiene Production Via Steam Cracking of Paraffinic Hydrocarbons

The steam cracking process is reported to be the predominant method of the three processes of production, accounting for greater than 91% of the world's butadiene supply. Figure depicts a flow chart for a typical olefins plant. While this does not represent any particular plant, and there are certainly many variations among olefins plants, this representation will provide the reader with a general understanding of the process.

The indicated feedstocks (ethane, propane, butane, naphtha and gas oil) are fed to a pyrolysis (steam cracking) furnace where they are combined with steam and heated to temperatures between approximately 1450-1525 F (790-830 C). Within this temperature range, the feedstock molecules "crack" to produce hydrogen, ethylene, propylene, butadiene, benzene, toluene and other important olefins plant co-products. After the pyrolysis reaction is quenched, the rest of the plant separates the desired products into streams that meet the various product specifications. Process steps include distillation, compression, process gas drying, hydrogenation (of acetylenes), and heat transfer. The focus of this review is 1,3-butadiene;however, since butadiene is created in the olefins plant pyrolysis furnace, and is present in the crude butadiene product stream at concentrations up to approximately 75 wt%, the olefins plant process and the crude butadiene stream are addressed in this publication to a limited degree.

The flow path of the C4 components (including butadiene) are indicated by bold [red] lines.While some olefins plant designs will accommodate any of the listed feedstocks, many olefins plants process only Natural Gas Liquids (NGLs) such as ethane, propane and sometimes butane. The mix of feedstocks, the conditions at which the feedstocks are cracked, and the physical plant design, ultimately determine the amount of each product produced, and for some of the streams, the chemical composition of the stream.

2.4.2 Butadiene Production via Catalytic Dehydrogenationof n-Butane and n-Butene (the Houdry process)

The catalytic dehydrogenation of n-butane is a two-step process; initially going from n-butane to n-butenes and then to butadiene. Both steps are endothermic.A major butane-based process is the Houdry Catadiene process outlined in Figure.

In the Houdry process, n-butane is dehydrogenated over chromium/alumina catalysts. The reactors normally operate at 12-15 centimeters Hg absolute pressure and approximately 1100-1260 F (600-680 C). Three or more reactors can be used to simulate continuous operation: while the first reactor is on-line, the second is being regenerated, and the third is being purged prior to regeneration. Residence time for feed in the reactor is approximately 5-15 minutes. As the endothermic reaction proceeds, the temperature of the catalyst bed decreases and a small amount of coke is deposited. In the regeneration cycle, this coke is burned with preheated air, which can supply essentially all of the heat required to bring the reactor up to the desired reaction temperature.

The reactor effluent goes directly to a quench tower, where it is cooled. This stream is compressed before feeding an absorber/stripper system, where a C4 concentrate is produced to be fed to a butadiene extraction system for the recovery of high purity butadiene.

2.4.3 Butadiene Production via Oxidative Dehydrogenationof n-Butenes (the Oxo-D or O-X-D process)

Oxidative dehydrogenation of n-butenes has replaced many older processes for commercial (on-purpose) production of butadiene. Several processes and many catalyst systems have been developed for the oxydehydrogenation of either n-butane or of n-butene feedstocks. Butenes are much more reactive, however, and they require less severe operating conditions than that of n-butane to produce an equivalent amount of product. Therefore, the use of n-butane as a feedstock in this process may not be practical.

In general, in an oxydehydrogenation process, a mixture of n-butenes, air and steam is passed over a catalyst bed generally at low pressure and approximately 930-1110 F (500-600 C). The heat from the exothermic reaction can be removed by circulating molten heat transfer salt, or by using the stream externally for steam generation. An alternate method is to add steam to the feed to act as a heat sink. The heat can then be recovered from the reactor effluent.Reaction yields and selectives can range from 70-90%, making it unnecessary to recover and recycle feedstock.

Butadiene Production via Oxidative Dehydrogenation

In the Oxo-D process shown in Figure, a mixture of air, steam, and n-butenes is passed over the dehydrogenation catalyst in a continuous process. The air feed rate is such that an oxygen/butene molar ratio of approximately 0.55 is maintained, and the oxygen is totally consumed. A steam to butene ratio of 10:1 has been reported as necessary to absorb the heat of reaction and to limit the temperature rise.

The reactor effluent is cooled and the C4 components are recovered in an absorber/degasser/ stripper column combination. The lean oil flows from the bottom of the stripper back to the absorber, with a small amount passing through a solvent purification area. Crude butadiene is stripped from the oil, recovered in the overhead of the stripper, then it is sent to a purification system to recover the butadiene product.

2.4.4 Conclusion of Product Selection :

Comparisons for all four products have been tabulated in Table 2.4. Based on the comparisons, the team has decided to select butadiene as the butane derivative product. The team decides to design butadiene production plant because; Increasing market demand especially in Asia region. Demand in Asia will grow at a more rapid rate, at 5% /year, although demand in some countries, particularly China, will be at more than 10%/year (CMAI, 2007). High market pricing of USD 0.64/lb which will give higher profit. Only one competitor in Malaysia, which is Titan Petchem. (M) Sdn. Bhd. Nearby neighbor, Singapore is only producing 60mt/yr. Aiming to be the major butadiene supplier in Asia

Table : Comparison between potential Butane Derivative Product

Polyisobutylene

Maleic AnhydridePropylene OxideButadiene

Market pricing$1.30 per pound(1996-2001)$0.63 per pound(2007)$0.64 per pound(1995-2000)$0.64 per pound(2006)

Complexity of the reactionsCopolymerization of isobutyleneOxidation of aromatic compound2 routes-chlorohydrin-indirectoxidationCatalytic dehydrogenation of normal butane

Strengths

Tires,tubes the largest end user accounting for 75-80% total consumption.Mature marketPrice stable and rising demandPresent market firmed and increasingHigh market potential

Weaknesses

Fortunes tied heavily to tires industryGrowth slowed down and No growthagriculturechemicaland oiladditivesDemand driven by automotive, housing and construction marketHeavily relied on automotive industry

The process which is here described in the project among these three processes is the production of the n-Butadiene by oxydehydrogenation process.

2.5 CONCEPTUAL DESIGN ANALYSIS

The Hierarchical Decomposition Approach suggested by Douglas (1988) is consisted of 3 hierarchy of decisions, which are:

Level 1: Batch vs. ContinuousLevel 2: Input-output StructureLevel 3: Recycle / Reactor SynthesisLevel 4: Separation

2.5.1 BATCH vs. CONTINUOUS

Continuous processes are designed so that every unit will operate continuously for close to a year at almost constant conditions before the plant shut down for maintenance. On the other hand, batch processes normally contain several units that are designed to be started and stopped frequently. During a normal batch operating cycle, the units are filled with material and perform their desired function for a specified period. After that, the units will be shut down, drained and cleaned before the cycle is repeated (Douglas J.M, 1988).According to Douglas (1988), there are a few criteria that needed to be considered when selecting the type of process, which are:1. Production rates:Plant that has a capacity that is greater than 10 x 106 Ib/yr is usually continuous. In contrast, if the plants capacity is less than 1 x 106 Ib/yr, then batch process will be chosen. Batch process is usually simpler and more flexible. Therefore, a satisfactory product can be produced with a large uncertainty in the design. Besides that, because of greater flexibility, batch plants are most common when a large number of products are produced in essentially the same processing equipment.2. Market forces:Batch plants are often preferred for products with a seasonal demand. Batch process is also preferred for products with a short life time.3. Operational problems:It is very difficult to build continuous processes when a low capacity of slurries must be handled. This is because it is very hard to pump slurries at low flow rate without having the solid settling out of the suspension and plugging the equipment problem. Some materials tend to foul the equipment frequently that the equipment must be shut down and cleaned very often. Hence, batch process is suitable for this kind of process instead of continuous. Butadiene demand is not seasonal and it is forecasted to have 3.5 percent growth per year through 2012 (CMAI, 2007). Besides, the production rate of butadiene plant that is decided is more than 10 x 106 Ib/yr and no slurry material is involved in the process. Therefore, continuous process is selected for butadiene production.2.5.2 Purification of FeedA decision to purify the feeds before they enter the process is equivalent to a decision to design a preprocess purification system. Some design guidelines to be considered are as follows (Douglas, 1988):i. If a feed impurity is not inert and is present in significant quantities, remove it. Otherwise it will lead to raw-material losses, and usually a much complicated separation system is required to recover the additional by-products.ii. If a feed impurity is present in a gas feed, as a first guess process the impurity.iii. If a feed impurity in a liquid feed stream is also a by-product or a product component, usually it is better to feed the process through the separation system.iv. If a feed impurity is present in large amounts, remove it.v. If a feed impurity is present as an azeotrope with a reactant, often it is better to process the impurity.vi. If a feed impurity is inert but is easier to separate from the product than the feed, it is better to process the impurity.vii. If a feed impurity is a catalyst poison, remove it.

Table shows the composition of the component in feed. The main component that is to be used in butadiene production is n-butane. However, the amount of isobutane in the stream is large (39.3 mole %). If isobutane is not separated from the feed and is processed, additional by product might be produced and thus complicated the separation process downstream. This will imposed additional cost (capital and operating) to the plant. Hence, with reference to guideline i and iv, the team decided to purify the stream first before entering to the reactor.

Table : Composition of the Components in the FeedComponentFormulaMole %

Propanei-Butane (isobutene)n-ButaneOther HydrocarbonC3H8C4H10C4H10C5+9.025.972.21.0

Figure : Purification of the feed

Figure shows the schematic diagram of the feed purification section. Distillation column is used to separate the impurities from the feed. As shown in the diagram, n-butane will be withdrew as side draw product, while isobutane and propane will be withdrew from the distillation column as the top product and C5+ as bottom product.To convert n-butane to butadiene, two stages of dehydrogenation reaction are involved (non-oxidative and oxidative dehydrogenation). The by product of the processes are hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), short chain hydrocarbon (C1-C3) and steam (H2O). Figure 4.3 shows the schematic diagram of two stages of dehydrogenation process. Only approximately 33% of n-butane will be converted to butadiene. Hence the unreacted n-butane will be recycled.

Figure : Two Stages Dehydrogenation of n-butaneSince only approximately 33% of n-butane will be converted to butadiene, the unreacted n-butane will be recycled after separated of the product stream. It is impossible to achieve sharp separation in the separation process. Hence, the recycle stream will consist of low fraction of impurities. Hence, part of the recycle stream will be purged to avoid accumulation of the impurities in the process stream.

2.6 Input Output Structure :

2.7 RECYCLE / REACTOR SYNTHESIS

Good reactor performance is of paramount importance in determining the economic viability of the overall design and fundamentally important to the environmental impact of the process (Smith, 2005). Therefore, issues to be addressed for a good reactor design should include;1. Reactor type2. Catalyst 3. Size4. Operating Conditions (Temperature and Pressure)5. Phase6. Feed Conditions (Concentration and temperature)At early stages in design, a kinetic model normally is not available. Thus, material balance calculations should be based on a correlation of the product distribution (Douglas, 1998). This type of kinetic analysis is very crude but in most cases the reactor cost is not nearly as important as the product distribution costs.

2.7.1 Reactor Selection

The selection of reactor is crucially important in order to make sure that the feed operates at its maximum. For single reaction, the highest rate of reaction is maintained by the highest concentration of feed (Smith, 2005). Based on the design guidelines for reactors by Douglas, 1998 stated that in order to maximize the conversion, reactor that always maintains the highest concentration should be selected. The ideal plug flow reactor (PFR) is chosen for all three reactors because it always maintains higher concentration of the reactant. Beside, all three reactions is in gas phase and PFR is also suitable for gas phase reaction.

Since the reaction is carried out in gas phase over a selective catalyst, the options for type of reactor selection for this type of reaction are fixed-bed catalytic reactor and fluidized bed reactor. The structure of fixed bed catalytic reactor is similar to a shell and tube heat exchanger. It is a tubular reactor that is packed with solid catalyst particles. It gives the highest conversion per weight of catalyst of any catalytic reactor. It is suitable to be used for high pressure reaction where smaller diameter cylinder vessels are used to allow usage of thinner vessel walls. Fixed bed catalytic reactor is also suitable for process that uses catalyst with a long life time. However, it has difficulty with temperature control because heat loads vary through the bed. Temperature in the catalyst might become locally excessive, which may lead to undesired product and catalyst deactivation. The catalyst is usually troublesome to replace too. Besides, channeling of the gas flow might occur in the reactor which will result ineffective use of parts of the reactor bed.

On the other hand, fluidized bed reactor is designed to be operated in a well mixed condition between the gas phase reactant and catalyst, which result in an even temperature distribution throughout the bed. Since the temperature is relatively uniform throughout the reactor, the possibility of having hot spots n the reactor can be eliminated. The heat transfer rate is high due to the rapid motion of the catalyst. It can also handle large amounts of feed and solids and has good temperature control. One of the disadvantages of fluidized bed reactor is high operating cost. Furthermore, the attrition of catalyst can cause generation of catalyst fines which could be carried over and lost in the system. This may cause fouling in the pipelines or equipment downstream. Hence, fluidized bed reactor is Preferable for gas-solid non-catalytic reactions. The advantages and disadvantages of both types of reactors are summarized in Table .

Table : Advantages and Disadvantages of Packed Bed and Fluidized Bed ReactorReactorFixed Bed Catalytic ReactorFluidized Bed Reactor

Advantages It gives the highest conversion per weight of catalyst of any catalytic reactor. Used for high pressure reaction where smaller diameter cylinder vessels is used to allow usage of thinner vessel walls. High heat transfer due to rapid motion of catalyst. The temperature is relatively uniform throughout the catalyst, thus avoiding hot spots. Can handle large amounts of feed and solids and has good temperature control.

Disadvantages Difficult to control the temperature because heat loads vary through the bed. Temperature in the catalyst becomes locally excessive, which may lead to undesired product and catalyst deactivation. The catalyst is usually troublesome to replace. Channeling of the gas flow occurs, resulting in ineffective use of parts of the reactor bed. High cost of the reactor and catalyst regeneration equipment. Attrition of catalyst can cause generation of catalyst fines which could be carried over and lost in the system, and may cause fouling in pipelines and equipment downstream. Preferable for gas-solid non-catalytic reactions.

After comparing both types of reactor, tubular fixed-bed catalytic reactor is chosen for all three reactors involve in the process. This is due to the:a. lower capital and operating cost The reactions involved in the butadiene production are required to be operated in high pressure condition. The required volume for tubular fixed bed catalytic reactor is smaller compared to fluidized bed reactor for high pressure operation, and thus lower capital cost. The operating cost for fluidized bed reactor is very high because it is more difficult to maintain the gas phase reactant and catalyst to be in the well mixed condition if it is operated in high pressure.b. less losses in catalyst There will be losses in catalyst if fluidized bed reactor is selected. The losses in catalyst are resulted from: catalyst will settle at the bottom of the reactor if it is not well mixed with the gas phase reactant. catalyst fine might be generated during the operation of the reactor when the catalyst hit on the wall of the reactor or through attrition. The catalyst fine will be brought to the downstream of the process when together with the product stream.c. lower maintenance cost If fluidized bed reactor is selected, the catalyst that settle at the bottom of the reactor will foul and plug the reactor while the generated catalyst fine will cause fouling in the pipeline and equipment downstream Plant might need to be shut down often for maintenance.

2.8 SEPARATION STRUCTURE The core reaction in butadiene production is the dehydrogenation using n-butane as the reactant. However, the feed stream contains significant amount of i-butane which is up to 39.3%. Thus, in order to increase yield, we need to convert i-butane into n-butane. The conversion is done in the Isomerization Reactor. The deisobutanizer column in pretreatment section employs side draws to yield purified n-butane. The n-butane stream is drawn as a vapor side product a few trays above the bottom, leaving a small heavy end stream which is only about 1% of the feed stream to be the bottom product. Thus, the system consists of two prominent products and we can assume that the small stream does not exist.The initial assumption for distillation columns is to have 0.02 mole percent of light key component in bottom and 0.01 mole percent of heavy key component in the overhead product. Also, we assume that all the component lighter than the light key leave with overhead and that all components heavier than the heavy key are taken at the bottoms.2.8.1 Design of Extractive Distillation Column :According to Seader (1998), extractive distillation is a partial vaporization process in the presence of a miscible, high-boiling, non-volatile mass separation agent, normally called the solvent, which is added to an azeotropic or non-azeotropic feed mixture to alter the volatilities of the key components without the formation of any additional azeotropes.2.8.2 Solvent selection:Since the solvent is the heart of extractive distillation, more attention should be paid on the selection of potential solvents. The affinity of hydrocarbon to polar solvent depends directly on their degree of un-saturation. A highly unsaturated hydrocarbon is more soluble in a polar solvent, and the solvent decreases the volatility of the hydrocarbon.Based on Perrys Handbook, several features are essential:1. The solvent must be chosen to affect the liquid-phase behavior of the key components differently; otherwise no enhancement in separability will occur.2. The solvent must be higher boiling than the key components of the separation and must be relatively nonvolatile in the extractive column, in order to remain largely in the liquid phase.3. The solvent should not form additional azeotropes with the components in the mixture to be separated.4. The extractive column must be a double-feed column, with the solvent feed above the primary feed; the column must have an extractive section.From Ullmans handbook (1985), there are five solvents that are commonly used in industry:a. n-methyl-2-pyrrolidone (NMP), b. dimethylformamide (DMF)c. Dimethylacetamide (DMAC)d. Acetonitrile (ACN)e. Furfural Of all possible solvents that can be used for the separation of butadiene-butane mixture we have chosen dimethylformamide (DMF). DMF is recommended as a potential entrainer because it gives great alteration in relative volatility. This in turn will make the separation easier and cheaper, as the utilities and trays required are lesser. Even though NMP gives greater value, it costs almost twice the DMF.

CHAPTER 3: PROCESS DESCRIPTION

Process DescriptionIn this project, butadiene is produced in continuous process. Here the 1,3-butadiene is produced by oxidative dehydrogenation reaction.

3.1 Preprocess Purification Deisobutanizer :

Figure : Preprocess Purification Section

The main objective of this pre-treatment unit is to extract n-butane from the feed. The extracted n-butane will be used as the reactant for the dehydrogenation process in order to produce butadiene.

The feed omposition is as follows :

Table : Feed CompositionComponentFormulaMole %

Propanei-Butanen-ButaneOther HydrocarbonC3H8C4H10C4H10C5+9.025.9072.21.0

From the table, it can be seen that the feed also contains significant amount of i-butane which is 25.90 %. In order to fully utilize the feed, the separated i-butane will be sent to isomerization section to undergo the isomerization process that will convert i-butane to n-butane.

The distillation column, C-101 will recover i-butane as the top product. The overhead product of the column also consists of significant amount of n-butane. For the sake of purity, the overhead product will enter the vapor recovery system which is the condenser (E-102). The operating temperature and pressure of E-102 are 40.71oC and 300 kPa. The condensed product which is mainly n-butane will be recycled back to C-101 while the vapor product which is mainly i-butane will be sent to the Alkylation Section. N-butane is extracted as the side product. This n-butane will enter the Reaction Section to undergo the dehydrogenation process. The bottom product of this column consists of the heavier product which is the condensate (C5+) together with considerable amount of n-butane. The bottom stream of column will then enter the reboiler (E-101) to recover the n-butane. 3.2 Dehydrogenation Section The third section of the plant is the dehydrogenation unit. The main objective of the unit is to convert the n-butane to the product desired, Butadiene. The section involves two steps of dehydrogenation processes which are the non-oxidative dehydrogenation and oxidative dehydrogenation. The processes are represented by Dehydrogenation Reactor (R-301) and Oxidative Dehydrogenation Reactor (R-302) respectively.

Figure : Dehydrogenation Section

The process gas from Section 1, the preprocess unit enters the furnace (F301) at 42.92oC. The furnace will heat up the process gas up to 600oC. The heated process gas will enter the Dehydrogenation Reactor (R301) where the n-butane will be converted in to butenes. Hydrogen and other byproduct such as C1 C3 will also form.The Dehydrogenation Reactor (R301) is a fixed bed tubular reactor operating at temperature of 500oC and pressure of 3 bar. The reaction is an exothermic reaction and the temperature is maintained using molten salt at the shell side of the reactor. The catalyst used in the reactor is the Pt0.3 Sn0.6Cs0.5K0.5 La3.0 which gives the conversion of 32.9 % and selectivity of 96%.The butenes from R301 will be cooled down from 600oC to 420oC by Dehydrogenation Inter-cooler (E301) before further supplied to Oxidative Dehydrogenation Reactor (R302). The R302 is also a fixed bed tubular reactor and is operating at temperature of 330oC and pressure of 3 bar. The reaction is an exothermic reaction and the temperature is maintained by molten salt. The catalyst used in the reactor is the Mo12Bi1Cr3Ni8Zr1Fe0.1K0.2 which gives the conversion of 99 % and selectivity of 96%.The Oxidative Dehydrogenation Reaction in R302 will convert the butenes to butadiene and also byproducts such as C1-C3, Carbon Oxide, Carbon Dioxide (CO2 ), water (H20) , and Hydrogen (H2 ). The product gases from the reactor need to be cooled down to 24.48oC by two Dehydrogenation Reactor Coolers which are the E302 and also E303 before can be sent to Section 3, the purification section.3.3 Purification Section The purity of 1,3-butadiene produced is demanded to be at least 99.6%. To achieve the high purity, purification section is employed to separate 1,3-butadiene from any impurities.

Figure : Purification SectionThe product stream which comes from reactor section contains component as heavy as water and as light as hydrogen.

Table 2: Product Stream from ReactorComponentNBP (oC)Mole Fraction

Hydrogen-252.600.0099

CO-191.450.00018

Oxygen-182.950.0329

CO2-78.550.00028

butenes-6.250.0029

1,3-butadiene-4.450.3487

n-butane-0.500.5815

H2O100.000.0233

TOTAL1

Due to wide array of components boiling point, different method of separation is utilized. First is by cooling the stream to achieve partial condensation which is happened in the previous section. The stream is then introduced to flash drum V-401 to separate the liquid phase which is essentially water from the gaseous phase. The liquid phase is sent to water treatment section while the gas is fed into compressor K-401 to do partial condensation by compression. The K-401 outlet stream is sent to a flash drum V-402 to separate off-gas from C4 which is the liquid phase.

Afterward, liquid C4 stream enter a distillation column C-401. Since the relative volatility is very low, thus extractive distillation is employed where solvent is introduced at the upper trays and feed enters the column at lower tray of C-401. The column is equipped with a condenser E-402 at 30oC and 304kPa of operating condition and a reboiler E-403 to supply heat at 70oC and 354kPa of operating condition. The overhead product consists of all the feed but solvent and 1,3-butadiene. Overhead product is sent back to C-101 Pretreatment Section. On the other hand, solvent extracts 1,3-butadiene from the feed stream and leave the column as bottom product to solvent recovery column, C-402.

The C-401 bottom product enters solvent recovery column, C-402. The purpose of C-402 column is to recover solvent and produce 99.7% purity of 1,3-butadiene. The heat to column C-402 is supplied by a reboiler E-403. The operating condition of E-403 is at temperature 208oC and pressure 355kPa. The bottom product is the solvent which will be recycled to column C-401, while overhead of the column is cooled down in a condenser with operating condition is at 27.45oC and 304kPa and collected in a reflux drum. Eventually, final product of 1,3-butadiene flows from the reflux drum to storage.

CHAPTER 4 : MATERIAL & ENERGY BALANCE

Material Balance4.1 Distillation Column :

Light Key Component : i-C4 Heavy Key Component : n-C4Feed = 3000 kmol/hrFeedDistillateBottoms

ComponentsXfmole %Xdmole%Xbmole%

C3270.009270.0371049900

i-C47770.259693.0840.9524767683.9160.036929

n-C421660.7227.5810.010418262158.4190.949868

C5+300.0100300.013202

Total30001727.66512272.3351

Split Fractions of LK = 0.892

For Distillate: LLK C3 : In = Out = 27 kmol/hrLK i-C4 : 777*0.892 = 693.084 kmol/hrHK n-C4 : (1 0.9965)*2166 = 7.581 kmol/hr Total : 727.665 kmol/hrFor Bottoms :LK i-C4 : 777-693.084 = 83.916 kmol/hrHK n-C4 : 2166-7.581 = 2158.419HHK C5+ : 30 kmol/hr

4.2 Non-Oxidative Dehydrogenation Reactor :

Reaction :

Assumption : 35% conversion of n-Butane to (1,cis,trans) Butenes

ComponentsFeed (kmol/hr)(kg/hr)Product (kmol/hr)(kg/hr)

n-C42158.419131339.79621402.9723581544.9619

Butenes00863.367648440.9659

H200671.50813331353.7604

131339.79622937.848083131339.688

n-C4 : 2158.419-(2158.419*0.35) = 1402.9723 kmol/hrButenes : ( 2158.419*0.35)*(4/3.5) = 863.36 kmol /hrH2 : (2158.419*0.35)*(4/4.5) = 671.50 kmol/hr

4.3 Oxidative Hydrogenation Reactor :

Reactions :

Amount of O2 added : (863.3676*3/10)*(1.07) = 277.1409996Conversion :99.16 % of reacted of Butenes for Butadiene & 50% O2 is reacted.ComponentsFeed (kmol/hr)(kg/hr)Product (kmol/hr)(kg/hr)

n-C41402.9723581372.39631402.9723581372.3963

Butadiene00856.115312248798.5728

Butenes863.367648348.58567.25228784413.380407

H2671.50813331343.016267671.50813331399.28865

O2277.14099968868.511987138.57049984614.39764

H2O00173.21312483268.53166

CO000.9065359826.1082362

CO2000.9065359840.0054328

139932.5102139932.681

n-C4 : In = out = 1402.97235Butadiene : 863.3676*0.9916 = 856.1153122Butenes : 863.3676 - (863.3676*0.9916) = 7.25228784H2 : In = Out = 671.5081333O2 : (277.1409996*0.50) = 138.5704998H2O : (277.1409996*0.50)*(10/8) = 173.2131248CO : ((863.3676 - (863.3676*0.9916)) / 2) = 0.90653598CO2 : ((863.3676 - (863.3676*0.9916)) / 2) = 0.90653598Energy Balance :4.3 Distillation Unit :Inlet Temperature = 313 KOverhead Temperature = 510 KTemperature Difference = 197 KDistillateFlow Rate CpEnthalpy

ComponentsXdmole%in Kg/hrKJ/kmol KH (KJ/hr)

C3270.037104986118876.701407972.619

i-C4693.0840.95247675840198.872101.47513855147.68

n-C47.5810.010418256439.698101.475151548.5491

C5+000114.0020

Total688.37109141826.5714414668.85

Q = mCpT Condenser Duty Qc = (Qv- QD-QL)V = 1.408836 kmol/secCp = 89.72 J/kmol KQv = 14.4088*3600*89.72*( 510-273)Qv = 107845163 KJ/hrL = 1.206707 kmol/secCp = 119 J/kmol KQL = 1.206*119*(298-273)QL = 12916260 KJ/hrSimilarly we can find the QD for distillate in which temperature difference is taken as ( 773-273) KReference Temperature is 273 KQD = 25361268.33 KJ/hrHence Condenser Duty Qc = 107845163 12916260 - 25361268.33Qc = 69567634 KJ /hr

For Bottom Inlet Temperature = 313 KBottom Temperature = 773 KTemperature Difference = 448 KBottomsFlow Rate CpEnthalpy

ComponentsXbmole%in Kg/hrKJ/kmol KH (KJ/hr)

C300068.3180

i-C483.9160.036929414867.128104.7663938611.6

n-C42158.4190.94986831125188.3104.766101305758

C5+300.013202282100117.5921580436.5

Total2149.6291132155.4106824806

Reboiler Duty QB = QW+QD+QC-QF-QLReference Temperature = 273KFor Qw temperature difference = 773-273=500 KQW = 224598914 KJ/hrFor feed stream Temperature difference = 313-273= 40 KQf = 16100760 KJ/hrHence Reboiler Duty QBQB = 224598914 +25361268.33 +69567634 -16100760 12916260QB = 290510796 KJ/hr 4.5 Non-Oxidative Dehydrogenation Reactor :Inlet Temperature : 773 KOutlet temperature : 603 KTemperature Difference : 170 KComponentM ( KJ/hr)

C3H818.774

i-C421.297

n-C422.383

Butenes68.02

Butadiene22.468

ComponentsProduct (kmol/hr)Cp (KJ/kmol K)Enthalpy H (KJ/hr)

n-C41402.97235197.95547213338.95

Butenes863.3676169.33324853494.41

H2671.508133330.0433429600.204

Total2937.84808375496433.56

Enthalpy of outlet stream of Non-oxidative dehydrogenation = 75496433.56 KJ/hr

4.6 Oxidative Dehydrogenation Reactor : Inlet Temperature : 603 KOutlet Temperature : 295 KTemperature Difference : 308 KComponentsProduct (kmol/hr)Cp (KJ/kmol K)Enthalpy H (KJ/hr)

n-C41402.97235168.92772995994.71

Butadiene856.1153122133.67435247652.81

Butenes7.25228784144.458322744.527

H2671.508133329.3816076710.783

O2138.570499831.6921352605.494

H2O173.213124836.4241943207.376

CO0.9065359831.4258774.271097

CO20.9065359845.46812695.26041

Total3251.44478117960385.2

Enthalpy of outlet stream of Oxidative Dehydrogenation Reactor = 117960385.2 KJ/hr.

CHAPTER 5 : DESIGN OF EQUIPMENTS

Design of Equipments

5.1 Design of Distillation Column Calculation for Rmin Rmin + 1 = ((i xi)/(i -))

X((i xi)/(i -))

C33.450.0091.473051

i-C41.380.259-0.17444

n-C410.722-0.29725

C5+0.410.01-0.00136

Total6.427255

By Trial and Error we get the value of = 1.228921306 Rmin = 5.427 R/ Rmin =1.1 R= 5.9699 6Calculations for Nmin :

Where xdi and xbi are molefractions light key component in distillate and bottom respectively & xdj and xbj are molefractions heavy key component in distillate and bottom.xDi 0.9524768

xBi0.0369294

xDj0.0104183

xBj0.9498683

1.375

By evaluating these values we get the minimum no. of trays required , Nmin = 23.376606Calculation for No. of Trays and Feed stage location :

x = 0.077866 y = (N-Nmin)/(N+1) = 0.576719 No. of trays N = 56Height of the Column = Tray spacing x No. of trays = 56 * 0.5 = 28 m

Feed Stage Location :

NR/Ns = 2.63039 and as we know NR + Ns = 56Hence NR = 40 = No. of Trays in Rectifying SectionAnd NS = 16 = No. of Trays in Stripping Section

COLUMN DIAMETER:Overall balance: Component balance: Equilibrium: L= D*RL =( 727.665/3600)*6 = 2.168681 kmol / sec V = L +D = 2.168681 + (727.665/3600) = 2.37081 kmol/secL = 750 Kg/m3 V = 2.3 Kg/m3

Liq-Vap Flowrate FLv = (2.168/2.3708)*(750/2.3)0.5 = 0.050656 m/sFlooding Velocity

For 0.5 m tray spacing K = 0.097 Flooding Velocity Uf = 0.097*((750-2.3)/2.3)0.5 = 1.748926 m/sDesign for 80% FloodingV = 1.399141 m/sFlowrate = Vapor velocity*M.W./ Density of Vapor Net Area = (Flowrate / velocity) = 8.249589 m2Downcomer Area = 12% of total Area C/S Area = 9.374533 m2Column Diameter = 3.4557315 mHence Actual Column Diameter = 3.5 mC/S Area Ac = 9.61625 m2Downcomer Area Ad = 1.15395 m2Net Area An= Ac - Ad = 8.4623 m2Active Area Aa= Ac - 2Ad = 7.30835 m2Hole Area = 10% of active area = 0.730835 m2

Check for weepingWeir Length lw = (0.77 x Column Dia)=(0.77*3.5)= 2.695 mMax how= 750 (Lv / L*lw ) =750*(2.168681/(750*2.695)) = 8.72537 mm of LiqMin how = 750 (V / L*lw ) =750*(2.37081/(750*2.695)) = 8.226993 mm of Liq Assume hw =50 mm hw+ how = 58.22699 mm From Graph K= 32Uh = ((K 0.9(25.4 - d0))/ v0.5 ) = 8.99395 m/s Actual min Vapor velocity through holes U = (min. vapor rate/ hole area) = 13.81919 m/sSince U> Uh , there is no chance for weeping

Plate Pressure DropPressure drop for flow of vapor through dry plate hd hd = (51*(Uh/C0)2*(V/L) ) = 86.38675 mm of liq Residual losses hr =( 12.5*103/ L ) = 16.66667 mm of liq Lhw+ how = 58.22699 mm ht = hd + (hw+ how) + hr = 86.386 + (58.226) + 16.66 = 161.7788 mm of liqP = L ht g =(750*161.778*9.81) = 0.172636 Psi (tolerable) Downcomer Backup CheckHeight of bottom plate of apron hap = 50-10 = 40 mmAap = hap*weir length = 0.040*2.695 = 0.1078 m2Ad = 1.15395 m2 & Aap = 0.1078 m2Hence select Am = 0.1078 m2Head loss in downcomer hd = 166*(Lv/L Am)2 =166*(2.168/(750*0.1078))2= 0.119437 mmhbc = (hw+ how)+ hd+ ht = (58.226) + 0.119 + 161.77 = 220.6236 mmNow (0.05+0.5)/2 = 0.275 = 275 mm220.6236 < 275 , hence Tray sapcing is adequate.Downcomer residence time tr (From Graph) = 8.804498661 > 3 sec hence it is also satisfactory.Check for Flooding & Entrainment Velocity = (Vapor flow rate/ Net area) = 1.329184 m/sActual % flooding = ( 1.329184/Floodig velocity) = (1.329 / 1.746) = 76 % which is satisactoryFor Entrainment FLV = 0.050656 0.09 < 0.1 (From Graph)Hence no Entrainment.Hydraulic GradientFva = (Q/Aa)( v)0.5 = (0.8 / 7.30835)*(2.3)0.5= 11.97591 m/s = froth density = 0.2 QP = Aeration Factor = 0.8 q = 2.168681*55 / 750 = 0.0981 m3/sec ha = 0.8 (0.1*hw + how) = 0.8*(0.1*58.22699) = 10.9803 cmhf = ha/ (2 QP 1)= 10.9803 / (2*0.8 1) = 18.30049 cmDf = 3.0975 mHydraulic Radius Rh = ( hf Df/2 hf + 100 Df )=( 18.30049*3.0975/2*18.3)+(100*3.0975) = 0.163666Velocity of Aerated Mass Uf = (100 q / hf Df) =(100*0.0981/ 18.3*0.2*3.09750)= 1.263771 m/sReynolds modulus = ( Rh Uf L/ L ) =(0.163*1.263*750/4.674*10^-4) =189179.3 f = 0.090 (from Graph) =( 10000*f * Uf2 weir length / Rh g ) = (10000*0.090*1.2632*2.695 / 189179.3*9.81) = 24.12745 mm

Tray Layout

Area for unperforated edge strip = 0.243743 m2Area of Calming Zone = 0.2595 m2Total Area available for perforations = Active Area (Area for unperforated edge strip + Area of Calming Zone)= 7.3083 (0.24374 + 0.2595)= 6.805108 m2 Area of holes = (*d2/4) = 0.000019625 m2No. of Holes = (Active area / Area of holes) = (6.805108/0.000019625)= 372400

5.2 Design of Heat Exchanger :

Mass Flow Rate (kg/hr)Tin (C)Tout (C)

Hot Fluid 131339.7500330

Cold Fluid80973.67160280

Difference34050

Q= 75496433.56 KJ/hr (From Non Oxidtive Rector Energy Balance)LMTD = ((340-50)/ ln (340/50)) = 151.9269 oC Assumption : Overall Heat Transfer Co-efficient Uf = 900 W/m2 oC

Area = 75496433.56 / 900*151.9269=154.0239 m2 Assumptions :Two pass Heat Exchanger with Square pitch Lay out with tube I.D. 0.016 m & the length of the Heat Exhanger is assumed to be 11 ft.CTP= 0.9CL= 1.0 Pitch Ratio (PR)= P/doPR= 1.25 do= 0.019 mP=0.02375L=3.35 mA = 154.0239 m2

Dia. Of Shell (Ds) = 0.637 * (1/0.9)0.5 * ( 154.0239*(1.25)2*0.019 / 3.35 ) = 0.78447 m 0.8 mNo. of Tubes

= 0.785* ( 0.9 / 1.0 )*( 0.82/ 1.252 0.019)(Nt) = 770 For two pass = 385 per pass Baffle Spacing is 60%B= 0.6 x 0.8 = 0.48 mShell Side : Feed from Non-Oxidative Reactor UnitT = 415 oC = 750 Kg/m3 , Cp = 1920 J/Kg K , = 4.67 x 10-4 , K = 0.652 W/m K , w= 6.04 x 10-4Tube Side : Water T = 220 oC = 1000 Kg/m3 , Cp = 4160 J/Kg K , = 4.2 x 10-4 , K = 0.610 W/m K

Equivalent Diameter (De)De = 4*( P2 (*d02/4))/( *d0) where P= d0*Pitch Ratio= 4*(0.023752 (*0.0192/4))/( * 0.019)t= 0.018818 mC= P do C= 0.00475 m Area of Flow = (Ds*C*B/P) = 0.07384 m2Gs = 131339.688/(3600*0.07384) = 494.5716 Kg/s m2Res= De Gs/ = 19907.67ho= 4283.297 W/m2 K Now , calculations for him = 80973.67 Kg/hr = 0.037488 m3/sC/s area of Flow = (Nt * di2 * / 8) = 0.077449 m2Um =0.037488/0.07744 = 0.48403 m/sRtube = 10088.85As hi = 1759.641 W/ m2 K

Hence overall Heat Transfer Coefficient (Uf) = 899.6566 W/ m2 K Design Summary :Area = 154.0239 m2 Dia. Of Shell (Ds) = 0.8 m No. of Tubes(Nt) = 770 For two pass = 385 per pass ho= 4283.297 W/m2 Khi = 1759.641 W/ m2 K (Uf) = 899.6566 W/ m2 K

5.2.1 Mechanical design of Heat Exchanger(a) Shell side detailsMaterial : carbon steelNumber of shell passes: oneWorking pressure: 0.1N/mm2Design pressure : 0.11N/mm2Permissible stress for Stainless Steel: 95 N/mm2(b) Tube side detailsNumber tubes: 770Number of passes: 2Outside diameter: 19.05mmInside diameter : 15.75Length: 3.35 mPitch triangular: 1 inchWorking pressure: 0.1 N/mm2Design pressure: 0.11N/mm2

Shell side(1) Shell thicknessts= PD/(2fJ+P)= 0.11*838/(2*95*0.85+0.11)= 0.57Minimum thickness of shell must be=6.3 mmIncluding corrosion allowance shell thickness is 8mm(2) Head thickness.Shallow dished and torispherical ts=PRcW/2fJ= 0.11*838*1.77/(2*95*1)= 0.858minimum shell thickness should be 10mm including corrosion allowance.(3) Transverse BafflesBaffle spacing =0.6*Dc= 48mmnumber of baffles,Nb+1=L/LS=3350/480=7Nb = 6Thickness of baffles, tb=6mm

NozzlesTube side nozzles diameter=180 mmShell side nozzles diameter = 180 mmThickness of nozzles = t =10mmSaddle supportMaterial: low carbon steelTotal length of shell: 6.6 mDiameter of shell: 800 mmKnuckle radius : 51.24 mmTotal depth of head (H)= (Doro/2)0.5= (800*51.24/2)0.5= 143 mmWeight of the shell and its contents = 11943kg = WR=D/2=400 mmDistance of saddle center line from shell end = A =0.5R=200 mm

5.3 Reactor Design :Reaction for Oxidative Dehydrogenation3 C4H8 + 10O2 = C4H6 + 4CO + 4CO2 + 8H2O + H2

Flowrate

C4H8863.3676kmol/hr

Steam in feed671.508133kmol/hr

Air in feed277.141kmol/hr

Total Fa1812.01673kmol/hr

Pressure Pa = 350 kPaConversion Xa = 0.9r = a/(a + bfo)2 , where r1 = moles butene converted/ft3 catalyst-hr.r2 = moles butadiene produced/ft3 catalyst-hr.f0 = equivalent reciprocal space velocity for zero age catalyst, ft3 catalyst-hr/mol feed.a and b = constants calculated from equationsIn a = -13.03794 + 0.19267 (1 x lo5 )In b = -4.48793 + 0.09814 (Ix lo5 )But K value is given by this equation : K = 2.1x104 exp (-63.116/ RT) which is an empirical equation Hence K= 20000 kmol/m3reactor/h/(kPa)2 Volume of Reactor V= (Fa/ K Pa)*((dXa/(1-Xa)2)V = (F/K Pa)*((1/(1-Xa)) - 1) V = (1812.01673/20000*350)*((1/(1 - 0.09)) 1)Hence Volume of Reactor V = 2.3297358 m3Now Volume of CatalystCatalyst particle diameter, dp = 5 mmCatalyst particle density = 2100 kg/m3Packing void fraction E = 0.45Volume of catalyst = (1-E )* Volume of reactor= (1 - 0.45) * 2.3297358 = 1.28135469 m3Consider length of tube = 5 mDiameter of tube = 2.5 cmVolume of one tube = /4 (d)2 (L)= /4 (2.5 x 10-2)2 (4)= 0.00245313 m3

Props.Shell Side (Water) Tube side (Butene Feed + H2O)

Cp 5.1865 (KJ/Kg oK)1.920 (KJ/Kg oK)

9 x 10-4 (Kg/m.Sec)4.187 x 10-4 (Kg/m.Sec)

K0.62 (w/m.oK)0.54 (w/m.oK)

995.40 (Kg/m3)750 (Kg/m3)

No. of tube = ( Volume of reactor / Volume of one tube )= 2.3297358 / 0.00245313 No. of tubes = 950 tubesArea of tube per pass:Atp = (/4) (d) 2 (Ntp)= (/4) (2.5 x 10-2)2 (950)At = 0.46609375 m2 Mass flow rate of reacting material = 57217.0976 kg/hr= 15.8936382 kg/secVelocity:

U = m/ m = 15.8936382 Kg/Sec U = 15.8936382 / 750*0.46609375U = 19.3748066 m/sec

NRe = du/(1-E)= (2.5 x 10-2) x (19.3748) x (794.09)/ (0.00000784) x (1 -0.45)NRe = 108736.159AO = Nt x x d xL= (950) x x (2.5 x 10-2) x (5)AO = 372.875 m2

Shell diameter: Consider the Triangular pitchCTP = 0.9CL = 0.7Take PR = Tube pitch ratio = 1.25

Ds = 0.637 * ( 0.7/ 0.9)0.5 *(409.66 x (1.25)2 x (2.5 x 10-2) / (0.5) )0.5

Ds = 0.95883493 m

= 0.785* ( 0.9 / 0.7 )*( 0.95882 / ( 1.252 * 0.0252 ) = 1059.10 > Total No of tube that is required.

De = 4*( P2 (*d02/4))/( *d0) where P= d0*Pitch RatioPT = 0.03125 mDe = 4*( ( 0.031252 ( *0.0252/ 4 )) / ( *0.025)) = 0.018 mC= P do= 0.03125 0.025 = 0.00625B = 0.6*DsB = 0.6 * 0.95883493B = 0.38353397As = Ds*C*B / PT = ( 0.95883493 x 0.00625 x 0.38353397 ) / ( 0.03125 )As = 0.07354915 m2 Gs = m/ As= 8.648 / 0.07354915

Gs = 117.581231 Kg/m2.secFrom the above equation,

( h0 * 0.018 / 0.62) = ho = 1725.81167 W/m2KTube side H.T.C:Nu = 0.023 (NRe)0.8 (Pr)0.4

( hi*di/k ) =

( hi*0.025/0.54) = hi = 280.163 W/m2KOver all H.T.C1/U0 = ( (1/h0) + (1/hi) + 0.005 )

= Uo = 39.0939011 W/m2 KNow,Total H.T area available = 372.875 m2Rate of H.T. is given byQ = UAT(4713400) = 39.0939011 x A x 30 A = 391.448444 m2 > A available

5.3.1 MECHANICAL DESIGNNow, Internal design pressurePd = 0.1 * 0.375= 0.0375 N/ mm2External Design PressurePd = 0.1*0.35= 0.0375 N/mm2Material of Construction is stainless steel (SS 316).Maximum Allowable Tensile Stress at 30 o C = 98 N / mm2SHELL DESIGN: For Internal Design Pressure P Design PressureD- Mean Diameter J- Joint Efficiency f- Design Or Permissible stress at design temperatureDi Internal Diameter Do Out Side Diameter ts = PDi / (2fJ P)

= 0.0375*1000 /(2*98*0.85 - 0.11) (Here Dia = 0.95883493 m 1000 mm)

= 0.26 mm = 5.00 mm (Because minimum thickness of the plate available is 5 mm) + C.A.Use 10 mm Thick Plate For Fabrication.

For External Design Pressure

Pc = 2.42 E ( t/D0 ) 5/2 / ((1-2 )3/4 [ ( L / Do ) 0.45 ( t / Do ) 1/2 ]) = {2.42*190*103*( 5 /1000)5/2}/{( 1-0.32 ) 3/4 [ (2000/1000) 0.45 (10/1000)1/2]} = 0.4367 N/mm2

Now, Allowable Pressure

P = Pc/4 = 0.4367/4P = 0.109 N/mm2 < Pd Means critical buckling pressure is less than External design pressure. So, we can use thickness of the shell ts = 5 mm. HEAD DESIGN: Here The Design Pressure is 0.0375 N/mm2 so we can use Torrispherical Head.Let Rc = Crown Radius = internal diameter of shell = 1000 mmR1 = Knuckle radius= 6% of Inside Dia. Of Shell= D * 0.06= 1000 *0.06= 60 mmTorrispherical head: Thickness of head th= (P*Rc*W ) / 2fJWhere, P - internal design pressureRc - crown radiusW - stress intensification factorW = 0.25 * (3+ (Rc/R1)0.5)W = 0.25 * (3+ (1000/60)0.5)W =1.770th = 0.11*1000*1.77 /2*98*0.85th = 1.17 mm= 5 mmThickness of Torrispherical head = 5 mm.

BRACKET SUPPORT DESIGN:-Let,Pt = Total force due to wind load acting on vesselH = Height of vessel above foundation.F = Vessel clearance from foundation to vessel bottom.Db = Diameter of bolt circle.W = Maximum weight of vessel with attachments & contents.n = no. of brackets.Pw = Wind pressure.P1 = Wind pressure for the lower part (Below 20m) of the vessel = 400 to 1000 N/m2Kp = Coefficient depending of the safe factor Wind pressure = Pw = Kp*h*Do*P1= 0.7*2.00*1.01*1000= 1414 NDensity of SS-316 = 7750 kg/m3Wt. of catalyst = 2000 kg = 20000 N W = wt. of vessel with attachment + wt. of contentWeight of Shell = (3.14*Ds2*L/4)*7750 = 3.683*7750 = 39970 kg =399700 NWeight of Tube = (3.14*Dt2*L/4)*7750 = 19.0117 kg = 190.11 NP = ( 4*Pw*(H-F) / n*Db ) + ( w/ n)= (4*1414*5.00 / 4*1.65) + (419890 / 4)P = 109257 N

Bracket: Base plate size a =140 mm, b=150mmAllowable bending stress for structural steel = f = 157.5 N/mm2 Pav = P / a*b = 109257 / 140*150 Pav = 5.20 N/mm2 f = 0.5 (Pav * b2 / T12 ) * ( a4 / a4+b4 ) = 0.5* (5.20 * (150)2 / T12) *(1404 / 1404+1504)157.5 = 1689.09 / T12T1 = 32 mmSo, thickness of base plate = T1= 32 mm = 3.2 cm.5.3.2 Thickness of the Insulation:From the heat balance it is clear that there is some amount of heat lost into the atmosphere.To limit the heat loss to the same figure an insulation is to be given to the reactor. The insulating material can be chosen as asbestos.Density of asbestos = 577 Kg/m3Thermal Conductivity of asbestos = 681.4 x 10-3 W/m2 KMaterial of the drier is stainless steelThermal Conductivity = 147.6 W/m2 KConvective Heat transfer Coefficient = 40 W/m2 KFrom Heat Balance Heat Loss = 97 KWD1 = 1 mD2 = 1.02 mt1 = 10 mmLet y be the thickness of insulation.D3 = D2 + 2y = 1.02 + 2yT1 = 603 K , T2 = 295 CWe have from the Continuity equationQ = (T1 T2) t 1 + t 2 + 1 k1 A1 k2 A2 Hc A3

A1 = (D1+ D2) x L/ 2 = 3.14 (1.0 + 1.02 ) x 7 /2 = 3.79 m2A2 = (D2 + D3) x L / 2 = 3.14 (1.02+ 1.02 + 2y) x 7/2 = 22.42 + 21.98 yA3 = x D3 x L = 3.14 x (1.02 + 2y) x 7 = 22.42 + 43.96 y

97x103 = ( 603 295) 10 x 10 -3 + y + 1 147.6 x 3.79 681.4 x 10 -3 (22.42 + 21.98 y) 56.8 (22.42+43.96 y) y = 38.78 mmTherefore the thickness of the insulation should be 40mm.CHAPTER 6 : PLANT LAYOUT

PLANT LAYOUT

A preliminary determination of the plant layout enables consideration of pipe runs and pressure drops, access for maintenance and repair, access in the event of accidents and spills, location of the control room and administrative offices. The preliminary plant layout can also help to identify undesirable and unforeseen problems with the preferred site, and may necessitate a revision of the site selection. The proposed plant layout must be considered early in the design work to ensure economical construction and efficient operation of the completed plant. The plant layout adopted will also affect the safe operation of the completed plant, and acceptance of the plant (and possibly any subsequent modification or extension) by the community.

6.1 Factors in Choosing a Suitable Plant Location : There are several major factors that contribute to the operability and economic aspects of a site location for a plant, which are the primary factor and specific factor.Primary Factors :Availability of Raw MaterialA plant with close proximity to the source of the raw material allows a lower cost of transportation. The cost of shipping raw materials and fuel to the plant site should be considered along with the cost of transporting the products to market so as to minimize the total transportation cost as much as possible while balancing that cost against other operating expenses. A seaport might have to be at a reachable distance from the site location if the raw material is to be imported.

Reasonable land price The cost of the land depends on the location itself. An ideal land will provide an economical land price to the total investment cost. It is then vital to choose a suitable land price when initiating a new plant in order to gain the highest economic and profit value.Proximity to marketThe plant should be constructed close to the primary market to minimize transportation costs. Local demand of product should also be taken into account in selecting a proper plant site. It would add as an extra point if both the raw material supplier and buyers are at a reachable distance.Electricity and waterAny chemical plant is in need of large quantities of water supply for cooling and other uses in the plant. Electricity is needed to run all the machines and equipments. Therefore, sufficient local water and power supply plants is required to ensure a smooth operation of the plant. Geographical and Weather :The climate conditions affect the budget and cost operation. It may be necessary to consider the yearly weather consideration.

Specific FactorsAvailability of low cost labor and servicesAny chemical processing plant should be located where sufficient labor supply is adequately available. The usual practice is to bring non-local, skilled construction workers and ample number of local, unskilled workers for training of plant operation. The cost of operation will reduce if inexpensive manpower for plant operation can be gathered from the surrounding area.

Transport facilitiesThe construction of the plant should be located close to road network, seaport and airport. All these major facilities will aid to smooth transportation of the raw feed, product, plant personnel and plant equipment supplies. Government incentives To attract investors to place their investment in a state, state governments offer attractive investments incentives. Some incentives grant partial or total relief from income tax payment for a specified period, while indirect tax incentives come in the form of exemptions from import duty, sales tax and excise duty.Waste and effluent disposal facilities Site location should also take into account the availability of efficient and satisfactory disposal system. This is to ensure that the factory waste and industrial effluent will have proper treatment if those are to be treated off-site.

Plant layout is often a compromise between a numbers of factors such as : The need to keep distances for transfer of materials between plant/storage units to a minimum to reduce costs and risks The geographical limitations of the site Interaction with existing or planned facilities on site such as existing roadways, drainage and utilities routings Interaction with other plants on site The need for plant operability and maintainability The need to locate hazardous materials facilities as far as possible from site boundaries and people living in the local neighbourhood The need to prevent confinement where release of flammable substances may occur The need to provide access for emergency services The need to provide emergency escape routes for on-site personnel The need to provide acceptable working conditions for operatorsThe most important factors of plant layout as far as safety aspects are concerned are: Prevent, limit and/or mitigate escalation of adjacent events (domino) Ensure safety within on-site occupied buildings Control access of unauthorized personnel Facilitate access for emergency services

Many factors must be considered when selecting a suitable site with respect to the marketing area, raw material supply, transport facilities, availability of labor, availability of utilities, availability of suitable land, environment impact, etc. All these factors play a significant role in the choice of the site. The overall site layout is shown.Several factors have been considered in laying out the site. The process units and ancillary building should be laid out to give the most economical flow of materials and personnel around the site. In term of safety, process area is located at enough distance from the place where there are a lot of personnel. 6.2 Plant Layout Consideration Factors When laying out the plant, these are the factors that we have considered;1. Inherent SafetyThe major principle in Inherent Safety is to remove the hazard altogether. The best method in achieving this is to reduce the inventory of hazardous substances such that a major hazard is no longer presented. However, this is not often achievable. Other possible methods to achieve an Inherently Safer design are; Intensification to reduce inventories Substitution of hazardous substances by less hazardous alternatives Simpler systems/processes to reduce potential loss of containment or possibility of errors causing a hazardous event

2. Domino EffectHazard assessment of site layout is critical to ensure consequences of loss of containment and chances of escalation are minimized. Domino maybe by fire, explosion (pressure wave and missiles) or toxic gas cloud causing loss of control of operations in another location.3. FireThere are four ways that fire can spread; Direct burning Convection Radiation ConductionThe use of vertical and horizontal compartmentation using fire-resisting walls and floors can prevent the spread of fire from its origin to the other part of the premises. Protection against domino by convection, conduction and radiation can be achieved by ensuring that the distances between plant items are sufficient to prevent overheating of adjacent plants compromising safety of that plant also. If this is not possible due to other restrictions, other methods such as fire walls, active or passive fire protection may be considered. 4. Explosion :Explosion propagation may be directly by pressure waves or indirectly by missiles. Inherently safety methods that should be considered are; Arranging separation distances such that damage to adjacent plant will not occur even in the worst case. Provision of barriers e.g. blast walls. Protecting plant against damage e.g. provision of thicker walls on vessels.5. Toxic gas releasesToxic gas releases may cause domino effects by rendering adjacent plants inoperable and injuring operators. Prevention of such effects may be affected by provision of automatic control system using inherently safer principles and a suitable control room.

6. Reduction of consequences of event on and off siteA plant layout design technique is also applicable to the reduction of the risks from release of flammable or toxic materials include; Locating all high-volume storage of flammable/toxic material well outside process area Locating hazardous plant away from main road Siting of plants in the open air to ensure rapid dispersion of minor releases of flammable gases and vapors and thus prevent concentrations building up which may lead to flash fires and explosions. Provision of ditches, dykes, embankments, sloping terrain to contain and control releases and limit the safety and environmental effects. Hazardous area classification for flammable gases, vapors and dusts to designate areas where ignition sources should be eliminated.7. Positioning of occupied buildingsThe distance between occupied buildings and plant buildings will be governed by the need to reduce the dangers of explosion. Evacuation routes should not be blocked by poor plant layout, and personnel with more general site responsibilities should be housed in buildings sited in a non-hazard area near the main entrance. Occupied buildings should not be sited downwind of hazardous plant areas.8. Aggregation / trapping of flammable vapors :To avoid aggregation and trapping of flammable/toxic vapors which could lead to a hazardous event, buildings should be designed so that all parts of the building are well ventilated by natural or forced ventilation. Flammable storage should be sited in the open air so that minor leaks or thermal out breathing can be dissipated by natural ventilation.

6.3 Site Layout : The site layout can be divided into two parts: Non-Process area area where there is no production activity and has low risk hazards to workers and process units. Process Area - consists of all processing equipments, butadiene is produced.6.3.1 Non-Process Area :

The non-process area usually occupies a smaller fraction of the overall plant site area. All the facilities in the non-process area should be located in a logical manner that considers site terrain, accessibility to roads, soil bearing capability and the climate including the wind direction and other unusual weather condition. This is important to avoid any undesired incident due to explosion or fire from the process zone will be easily spread to the non-process area. Taking this into account, the entire process area where the reaction and separation occurs is surrounded with a buffer zone to ensure that surrounding buildings or sites are not affected in case of an emergency. Among the buildings or units in the non-process area are: -a) Guard PostGuard posts are located at the entrance of the site in order to ensure that only authorized personnel gets access into the plant. There are 5 guard posts that are situated at the crucial entrances in the plant: Main entrance guard post to control the flow in and out of personnel or cars between the site and public area. Emergency entrance guard post security check for emergencies such as ambulance, fire engine or other special occasions. Process entrance guard post As shown in the layout, there are two different main entrances to the plant. The first one is for public entrance where only cars and other small vehicles are allowed to pass through. The second main entrance is only open to trucks. This is to avoid congestion and at the same time reduce the hazard of material spillage at the plant. With two different entrances, the public are less exposed to the danger of chemicals exposure or accidents with the trucks.

b) Administration Building

The administration block is built adjacent to the main entrance. This is to allow the administration employees to enter their office without passing through the hazardous process area. As shown in the plant layout, the administration building is place near to the process area. This location is most strategic as it is aligned with the process area. This arrangement allows the employees at the administration building to alert on any mishap at the process area that is visible from the administration building but far enough to ensure that no accidents from the processing area can affect the administration block.

c) CafeteriaCanteen provides meals for the employees and visitors. Canteen is located in the public zone and far away from the process area to avoid contaminant in food and ensure safety of the public.

There are other facilities that should be located in the non-process area including surau, gymnasium, car park and also fire station.

6.3.2 Process AreaProcess zone is an area where all processing equipment is allocated and is deemed as a hazardous area, thus precaution has to be applied at all times. The buildings or units situated in this process zone are: Process zone guard post Control Building Laboratory Wastewater treatment plant Plant Area Utilities Storage area Fire assembly points Flare area

a) Process zone guard postThis facility is to ensure no unauthorized personnel will be access into the process area by using a security pass, to record the personnel activity, such as check-in and check-out between process zone and public zone. The purpose of this process zone guard post is to ensure that all the personnel will obey to the plant rule and regulations.

b) Control Building :All the control valves for the whole process area will be controlled and monitored from this central control building. The control rooms are designed with blast proof construction and have emergency backup power and air conditioning. In case of emergency occurs in the plant, control room will be the assembly point in the process area. At least two escape routes for operators/personnel must be provided from each level in process buildings.

c) LaboratoryHere the quality of the purity of butadiene is tested to determine whether it meets the specifications or not. All the result will be sent to the control room and some adjustments in controlling will be made, if needed. Thus, the distance between laboratory and control room is not too far. Laboratory staffs will also perform an analysis regarding waste of the process before being channeled to nearby environment.d) Wastewater Treatment PlantThe waste stream from Plant Area will first flow into the Wastewater Treatment plant to separate the impurities from the water. The impurities will be treated before being recycled back to the process released to the environment. It is located adjacent to the main process unit so that the wastewater effluents from the process units can be channeled easily.e) Plant AreaThis area is the major processing unit where the butadiene is produced. Safety, economy, operability and ease of maintenance are considered during the allocation of each equipment within the area. Adequate spacing between equipment is also considered to minimize the spread of fire in case it happens. Distances between each unit are also well designed to prevent any hazards from occurring.

f) Utilities This unit will supply cooling water, low pressure steam, instrument air and some other utilities to the main process unit. For this plant, the utilities located near to plant area where all the process of producing butadiene occurs. Its location is perfectly suitable to give the most economical run of pipe to and from the process unit. The utilities and control building is situated near to the utilities for easy monitoring.g) Storage areaThis unit stores vessels containing chemical substance, lubricants, and catalyst used for the process. It also stores chemicals needed for the waste water treatment plant. It is situated next to the waste water treatment plant.h) Warehouse :Warehouse stores all the equipments spare parts. It is placed near to the workshop to ease the maintenance job and to conduct hot work.i) Expansion SiteAmple expansion areas are allocated at the process area for future expansion in case the management decides to increase production rate or other crucial considerations. j) Fire assembly pointsIn case of emergency, the assembly point in the plant for public zone will be located in the nearest car park area and next to the canteen. For process zone; the assembly point will be near to the QC Laboratory building and next to the Utilities and Control building for personnel working there. Once gathered, wait for further instruction from Health, Safety and Environment personnel or from fire department personnel. There are a total of 5 assembly points planned at the site.

k) Flare AreaFlare is used to burn all excess gas that is emitted from the process units as well as to burn some of the waste gas from waste treatment area. The flare is located far from the process area and administration complexProcess Unit :Table below summarizes the layout consideration for process unitsTable : Layout Consideration for Process UnitPROCESS UNITLAYOUT CONSIDERATIONS

Process Area Located in well ventilated area with leak detector to allow maximum safety if there is leakage or spillage Located as far s possible from ignition sources

Instrumentation Instrumentation control cables are routed underground to prevent any hazards. Fire proofing protection should be considered.

Pipelines Consider types of fluid, temperatures, pressures and flow condition

Reactor/Column/Heat Exchanger/Pressure Vessels Isolated from other equipment and from flammable, toxic or inert materials. Consider internal refractory of insulation due to overheating and rupturing.

`Figure : Plant Layout of Butadiene Production Plant

CHAPTER 7 : COST ESTIMATION

Cost Estimation

7.1 Direct Cost :

1.) Purchased EquipmentSr. No.Equipment NameQuantityPrice in Rs.

1Dehydrogenation Reactor 13424735

2OxydativeDehydrogenation Reactor 1749890

3Deisobutanizer116352892

4Extractive Distillation Column126147632

5Solvent Recovery Column14412826

6Furnace1163076706

7Flash Drum16528834

8Dehydrogenation Inter-Cooler13478284

9Dehydrogenation Reactor Cooler13928860

10Compressor118602226

11Deisobutanizer Pump11133838

12Extractive Pump1522756

13Recovery Pump1268740

14Feed Pump1368136

15Solvent Pump1176706

16Tanks283372220

17Heat Exchanger1040000000

Total Cost of Equipment = 372545281 Rs.

2.) Purchased Equipment InstallationInstallation of all the equipments listed, structural supports, paints (Taken as 25% of the purchased equipment cost)= 85685414 Rs.

Sr. No.DescriptionGrand Total cost in Rs.

1Purchased Equipment372545281

2Purchased Equipment Installation85685414

3Instrumentation and Control (17%)63332697

4Piping (20%)74509056

5Electrical (10%)37254528

6Building (17%)63332697

7Yard Improvement (3%)11176358

8Service Facilities (9%)33529075

9Land (15%)55881792

Total Direct Cost (D) = 797246902 Rs.7.1.1 Indirect Cost (I)

1) Engineering and Supervision

Total Engineering and Supervision Cost is taken as 8% of the Total Direct Cost = 87,697,159.27 Rs.

2) Construction Expenses

Total Construction Expenses cost is taken as 7% of the Total Direct Cost = 63,779,752.20Rs.

3) Contractor's Fee

Total Contractor's fee is taken as 5% of the Total Direct Cost = 39,862,345.12Rs.

4) Contingency

Total Contingency cost is taken as 8% of the Total Direct and Indirect cost = 55,807,283.17 Rs.

Sr. No.DescriptionGrand Total cost

1Engineering and Supervision Cost (11%)87,697,159.27

2Construction Expenses (8%)63,779,752.20

3Contractor's Fees (5%)39,862,345.12

4Contingency (7%)55,807,283.17

(% of Total Direct Cost)Total Indirect Cost (I) = 247,146,539Rs Total Fixed Capital Investment (D + I) = 1,044,393,442 Rs. Working Capital (WC), 15% of TCI = 184,304,725.10 Rs. Total Capital Investment (TCI) = 1,228,698,167.31 Rs.

7.2 Total Product CostDetermination of the necessary Capital Investment is only one part of a complete cost estimate. Another equally important part is the estimation of costs for operating the plant and selling the products. These costs can be grouped under the general heading of Total Product Cost.Basis:1.) Total cost is calculated on the basis on the Annual Cost Basis 2.) Number of days working per year is taken as 330 days 3.) Plant is running in three shifts i.e. 24 hrs per day 4.) Capacity of the plant per year = 1512939600 Kg/yrManufacturing Cost1.) Direct Production Costs a.) Raw MaterialSr. No.Quantity per annum KgCost per unit in Rs.Total annual cost in Rs.

1LPG1,512,939,600.0026.0039,336,4296

Total Cost of Raw Materials = 39,336,4296 Rs

Total Direct Production Cost :Sr. No. Description%Cost in Rs.

1Raw Material50.0039,336,4296

2Operating Labour15.005,900,464,4.40

3Operating Supervision15.00885,069,6.66

4Utilities10.005,000,000.00

5Maintainance and Repair3.5011176358.45

6Operating Supplies15.001676453.77

7Laboratory Charges0.201,180,0928.88

8Patents and Royalities0.000.00

9Catalyst (yeast)2,400,000.00

Total Direct Production Cost = 493273378Rs.2) Fixed Chargesa) Depreciationi) Annual cost of Depreciation for Machinery and Equipment is assumed as 10% of the Fixed Capital Investment = 10,443,934.42 Rs.ii) Annual cost of Depreciation for buildings is taken as 3% of the Initial Cost of buildings = 1,899,980.94 Rs. iii) Annual cost of Depreciation for Instrumentation & Controls, piping, Electrical equipment and Materials is assumed as 5% of FCI = 52,219,672.11 Rs.b) Taxes : Annual property taxes for plant is assumed as 1% of the Fixed Capital Investment = 10,443,934.42 Rs. c) Insurance : Annual cost of Insurance is assumed as 1% of the Fixed Capital Investment = 10,443,934.42 Rsd) RentAnnual cost of Rent for Land and Buildings = 0.00 Rs.Total Annual Fixed Charges :S. No.DescriptionTotal Annual cost in Rs.

1.00Depreciation64563587.47

2.00Taxes10,443,934.42

3.00Insurance10,443,934.42

4.00Rent0.00

Total Fixed Charges = 85451456Rs.4) Plant Overhead CostsAnnual Plant Overhead Costs is assumed as 30% of the total cost of operating labor, supervision and maintenance = 2,038,193,918.38 Rs.Total Manufacturing Cost :S. No.DescriptionTotal Annual cost in Rs.

1Direct Production Cost47,319,169,059.24

2Fixed Charges50,706,388.08

3Plant Overhead Cost2,038,193,918.38

Total Manufacturing Cost = 49,408,069,365.70 Rs.7.2.1 General Expenses1) Administrative Expenses[9]Annual cost of Administrative expenses is assumed as 25% of the total cost of operating labor = 1,475,1161.10 Rs.2) Distribution and Marketing ExpensesAnnual cost of Distribution & Marketing expensesis assumed as 10% of the Total Product Cost = 49,327,337.82 Rs.3) Research and DevelopmentAnnual cost of Research and Development = 24,663,668.91 Rs.4) Financing (interest)Annual cost of Financing (interest) = 0.00 Rs.Total General Expenses (G)S. No.DescriptionTotal Annual cost

1Administrative Expenses1,475,1161.10

2Distribution and Marketing Expenses49327337.82

3Research and Development24,663,668.91

4Financing (interest)0.00

Total Cost of General Expenses = 88,742,167.82 Rs.Total Product Cost (TPC), M + G = 691,176,512.14 Rs.

7.3 Spreadsheet for Estimation of Total Capital Investment

S. No.DescriptionCost in Rs.Cost in Rs.

Direct Costs

1Purchased Equipment372,545,281.52

2Purchased Equipment Installation85,685,414.75

3Instrumentation and Controls63,332,697.86

4Piping74,509,056.30

5Electrical Equipment and Materials37,254,528.15

6Buildings (Including services)63,332,697.86

7Yard Improvements11,176,358.45

8Service Facilities33,529,075.34

9Land55,881,792.23

Total Direct Costs (D)797,246,902.45

Indirect Costs

10Engineering and Supervision87,697,159.27

11Construction Expenses63,779,752.20

12Contractors Fee39,862,345.12

13Contingency55,807,283.17

Total Indirect Costs (I)247,146,539.76

Fixed Capital Investment (FCI), D + I1,044,393,442.21

Working Capital (WC), 15% of TCI184,304,725.10

7.4 Spreadsheet for Estimation of Total Product Cost

S. No.DescriptionCost in Rs.Cost in Rs.

Manufacturing Costs

Direct Production Costs

1Raw Materials393,364,296.00

2Operating Labor59,004,644.40

3Operating Supervision8,850,696.66

4Power and Utilities5,000,000.00

5Maintenance and Repairs11,176,358.45

6Operating Supplies1,676,453.77

7Laboratory Charges11,800,928.88

8P