CHAPTER 1
INTRODUCTION: PROJECT CONCEPTION AND LITERATURE REVIEW
Butadiene is a versatile raw material used in the production of a wide variety of synthetic rubbers and polymer resins as well as a few chemical intermediates. The largest uses for butadiene are the production of styrene butadiene rubber (SBR) and polybutadiene rubber (BR), which are used mainly in tire products.[ Anonymous, (February 2009),Butadiene Uses and Market Data ]
Butadiene is one of the components used in the manufacture of acrylonitrile-butadiene-styrene (ABS), styrene-butadiene (SB) copolymer latex, styrene-butadiene block copolymers and nitrile rubbers. 1, 3-Butadiene ranks 36th in the most produced chemicals in the United States. Three billion pounds per year are produced in the United States and 12 billion globally. World butadiene consumption in the synthetic rubber and latex applications is forecast to grow at an average rate of about 2%/year.[ Anonymous, (February 2009),Butadiene Uses and Market Data]
The region seeing the strongest performance has been Asia due to increased production of finished goods in the electronics, automobile and tire
sectors. The major source of butadiene is as a byproduct in the steam cracking of naphtha and gas oil to make ethylene and propylene. The butadiene is extracted from the C4 cracker stream using extractive distillation. Butadiene is a colorless, non corrosive liquefied gas with a mild aromatic or gasoline-like odor. Butadiene is both explosive and flammable because of its low flash point.[ Anonymous, (February 2009),Butadiene CAS No: 106-99-0]
1.1) History and Background
1.1.1) History
In 1863, a French chemist isolated a previously unknown hydrocarbon from the pyrolysis of amyl alcohol. This hydrocarbon was identified as butadiene in 1886, after Henry Edward Armstrong isolated it from among the pyrolysis products of petroleum. In 1910, the Russian chemist Sergei Lebedev polymerized butadiene, and obtained a material with rubber-like properties. This polymer was, however, too soft to replace natural rubber in many roles, especially automobile tires.[ Anonymous, (February 2009),History Butadiene]
The butadiene industry originated in the years leading up to World War II. Many of the belligerent nations realized that in the event of war, they could be cut off from rubber plantations controlled by the British Empire, and sought to remove their dependence on natural rubber. In 1929, Eduard Tschunker and Walter Bock, working for IG Farben in Germany, made a copolymer of styrene and butadiene that could be used in automobile tires. Worldwide
production quickly ensued, with butadiene being produced from grain alcohol in the Soviet Union and the United States and from coal-derived acetylene in Germany.[ Armstrong, H.E. Miller, A.K. (1886).]
1.1.2) Background
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.[ Sun, H.P. Wristers, J.P. (1992).]
The name butadiene can also refer to the isomer, 1,2-butadiene, which is a cumulated diene. However, this allene is difficult to prepare and has no industrial significance.
In the United States, western Europe, and Japan, butadiene is produced as a byproduct of the steam cracking process used to produce ethylene and other olefins. When mixed with steam and briefly heated to very high temperatures (often over 900 °C), aliphatic hydrocarbons give up hydrogen to produce a complex mixture of unsaturated hydrocarbons, including butadiene. The quantity of butadiene produced depends on the hydrocarbons used as feed. Light feeds, such as ethane, give primarily ethylene when cracked, but heavier favor the formation of heavier olefins, butadiene, and aromatic hydrocarbons.
Butadiene is typically isolated from the other four-carbon hydrocarbons produced in steam cracking by extraction into a polar aprotic solvent such as acetonitrile or dimethylformamide, from which it is then stripped by distillation.
Butadiene can also be produced by the catalytic dehydrogenation of normal butane. The first such commercial plant, producing 65,000 tons per year of butadiene, began operations in 1957 in Houston, Texas.
In other parts of the world, including eastern Europe, China, and India, butadiene is also produced from ethanol. While not competitive with steam cracking for producing large volumes of butadiene, lower capital costs make production from ethanol a viable option for smaller-capacity plants. Two processes are in use.
In the single-step process developed by Sergei Lebedev, ethanol is converted to butadiene, hydrogen, and water at 400–450 °C over any of a variety of metal oxide catalysts:
This process was the basis for the Soviet Union's synthetic rubber industry during and after World War II, and it remains in limited use in Russia and other parts of Eastern Europe. In the other, two-step process, developed by the Russian chemist Ivan
Ostromislensky, ethanol is oxidized to acetaldehyde, which reacts with additional ethanol over a tantalum-promoted porous silica
catalyst at 325–350 °C to yield butadiene:[ Beychok, M.R. and Brack, W.J, June 1957]
2 CH3CH2OH → CH2=CH-CH=CH2 + 2 H2O + H2
Figure 1.1: Structural Chemical Reaction of Ethanol
CH3CH2OH + CH3CHO → CH2=CH-CH=CH2 + 2 H2O
Figure 1.2: Structural Chemical Reaction of Ethanol by react With tantalum-promoted porous silica
This process was used in the United States to produce government rubber during World War II, and remains in use today in China and India.
1.1.3) Butadiene Synonyms and Abbreviations Biethylene Buta-1,3-diene Butadieno Divinyl Erythrene Vinylethylene 1,3-Butadiene
1.1.4) Chemical-Physical Properties product and raw material
Molecular formula C4H6 Molar mass 54.09 g mol−1
Appearance Colorless gas or refrigerated liquid Density 0.64 g/cm at -6 °C, liquid
Melting point -108.9 °C, 164 K, -164 °F Boiling point -4.4 °C, 269 K, 24 °F Solubility in water 735 ppm Viscosity 0.25 cP at 0 °C
1.1.5) Importance of Butadiene production
The 1,3-butadiene is the simplest member of the series of conjugated dienes, which contain the structure C=C−C=C, the C being carbon. The wide variety of chemical reactions peculiar to this system makes butadiene important in chemical synthesis. Under the influence of catalysts, butadiene molecules combine with each other or with other reactive molecules, as acrylonitrile or styrene, to form elastic, rubberlike materials. In uncatalyzed reactions with reactive unsaturated compounds, such as maleic anhydride, butadiene undergoes the Diels-Alder reaction, forming cyclohexene derivatives. Butadiene is attacked by the numerous substances that react with ordinary olefins, but the reactions often involve both double bonds (e.g., addition of chlorine yields both 3,4-dichloro-1-butene and 1,4-dichloro-2-3,4-dichloro-1-butene). At atmospheric conditions, 1,3-butadiene exists as a colourless gas, but it is liquefied either by cooling to -4.4° C (24.1° F) or by compressing to 2.8 atmospheres at 25°C. [Kirshenbaum, I. (1978)]
1.2) Application of Products
Nearly all (96%) of the butadiene produced globally is as a co-product of the steam cracking of naphtha and gas oil to make ethylene and propylene. After ethylene and propylene are extracted from the cracker, a “C4 stream” is separated from the process which contains predominately hydrocarbons containing four carbon atoms, e.g. butadiene and butenes.
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
automobile tyres. SBR is also used in adhesives, sealants, coatings and in rubber articles like shoe soles. Polybutadiene is also used in tyres and can be used as an intermediate in the production of acrylonitrile-butadiene-styrene (ABS). ABS is widely used in items such as telephones, computer casings and other appliances.[ Anonymous, (June 21, 2007),Product Safety Assessment, Butadiene]
Other polymers made from butadiene include styrene-butadiene latex, used for example in carpet backings and adhesives; nitrile rubber, used in hoses, fuel lines, gasket seals, gloves and footwear; and styrene-butadiene block copolymers which are used in many end-uses ranging from asphalt modifiers (road and roofing construction applications), to adhesives, footwear and toys.[ Anonymous, (June 21, 2007),Product Safety Assessment, Butadiene]]
Chemical intermediates made from butadiene include adiponitrile and chloroprene which are used, respectively, in the manufacture of nylon and neoprene.
1.2.1) Synthetic Elastomer
The synthetic elastomers of the invention have incorporated therein from about 11-50%, preferably from about 20-40%, of a liquid, high vinyl 1,2-polybutadiene resin having a pendant vinyl group for every other chain carbon which is capable of crosslinking to a very high degree. The preferred liquid, high vinyl 1,2 polybutadiene has from about 80-95 mole %, most preferably from about 90-95 mole % 1,2 vinyl structure. [Anonymous, (1987), Synthetic elastomeric with improved chemical, aging and oil resistance]
In the method of the invention, the previously polymerized, liquid, high vinyl content 1,2-polybutadiene is incorporated into an elastomer selected from the group consisting of propylene copolymer rubbers and ethylene-propylene-nonconjugated diene terpolymer rubbers. The previously polymerized liquid, high vinyl content 1,2-polybutadiene is incorporated during the polymerization of the elastomer to provide additional cure sites on the resulting elastomer. Rather than attempting to directly polymerize the polybutadiene onto the backbone of the ethylene-propylene chain, the polybutadiene is solution blended after catalysis and prior to separating and drying the polymerized elastomer. The polybutadiene is added prior to precipitating and drying the polymerized elastomer. The resulting elastomer is peroxide cured to produce an insulating material exhibiting excellent electrical characteristics, ease of compounding, and improved performance at extreme temperatures and pressures when exposed to solvents, oil and aqueous environments.[ Anonymous, (1987), Synthetic elastomeric with improved chemical, aging and oil resistance]
Synthetic olefin polymers are popular as electrical insulating materials because of their ease of compounding, good extrudability and excellent electrical characteristics. These polymers also find use as valve seats, and in other applications. In particular, ethylene-propylene copolymer rubbers, known as EPR, and ethylene-propylene-nonconjugated diene terpolymer rubbers, known as EPDM have been widely employed as the primary insulating materials for electrical wire and cable. These materials have the characteristics of flowing and/or distorting at elevated temperatures and under extreme pressures and are sensitive to swelling and dissolving in various hydrocarbon solvents and oils. Where insulated wire and cable is needed for extreme conditions, EPR and EPDM elastomers have been physically blended with low molecular weight polybutadiene in a roll mill, Banbury mixer, or the like. The physical blending or incorporation of the polybutadiene into the EPR/EPDM rubber provides additional cure sites for greater cross link density. An increase in cross link density has been found to enhance the chemical aging and oil resistance of the elastomer, improving the performance of the elastomer in extreme environmental conditions. U.S. Pat. No. 3,926,900 to Guzy et al., issued Dec. 16, 1975, discusses the physical blending of liquid 1,2 polybutadiene with EPDM polymers. [Anonymous, (1987), Synthetic elastomeric with improved chemical, aging and oil resistance]
1.2.2) Polymer and Resin
Engineering resins is the term for a group of polymer plastics which exhibit a greater tendency to form crystals in their solid state than their more amorphous cousins. The additional level of long-range order at the molecular
scale produces a different set of physical properties which suit the engineering plastic resins to a wide variety of applications that amorphous resins cannot fill. In general, engineering plastic resins are physically stronger and less flexible than amorphous resins and show greater resistance to fatigue, friction and wear. [Anonymous, (2007), Engineering Resin]
1.2.3) Polybutylene Terephthalate (PBT)
PBT engineering plastic resins are used to fabricate components found in computer keyboards, appliances, fluid handling systems, cars and trucks, electrical connectors, and industrial systems and controls. This product list is a testament to the versatility of the compound and is a direct result of its many outstanding characteristics. Stability and resistance to temperature extremes, along with a superior ability to be molded into complex or fine shapes makes PBT one of the most important engineering polymers.[ Anonymous, (2007), Engineering Resin]
1.2.4) PC/ABS
A true industrial thermoplastic, this engineering resins blend combines the most desirable properties of both materials; excellent features of ABS and the superior mechanical properties and heat resistance of polycarbonate. PC-ABS blends are widely used in automotive, electronics and telecommunications applications. This engineering plastic resins blend is ideal for the rapid production
of prototypes, tooling and the direct (tool-less) manufacturing of production parts.[ Anonymous, (2007), Engineering Resin]
1.2.5) Nylon 66 (Polyamide 66) resin
A thermoplastic resin with excellent mechanical, thermal and electrical properties will use as raw materials of fiber, film and engineering plastic. Engineering plastic resins are replacing the previous metals at a rapid pace. Nylon has a proven record of outstanding service in a wide range of applications for all industries.[ Anonymous, (2007), Engineering Resin]
1.2.6) Styrene Butadiene Rubber (SBR)
Styrene butadiene rubber (SBR) is the outcome of synthetic rubber research that took place in the United States and Europe under the impact of the shortage of natural rubber, a German chemist developed a series of synthetic elastomers by copolymerization of two compounds (styrene and butadiene) in the presence of a catalyst. The first step involved in the process is to let styrene and butadiene react together. The new synthetic rubber that was formed consists of about 25% styrene, with butadiene making up the rest, which in principle had the same properties as natural rubber. This rubber is considered to be the highest volume general purpose and the most common type of synthetic rubber. [Anonymous, (2007), Types of Synthetic Rubber]
1.2.7) Properties of Styrene Butadiene Rubber
This type of rubber is usually very weak unless reinforcing fillers are incorporated. With suitable fillers, this becomes a strong rubber.
It has similar chemical and physical properties like natural rubber.
It has better abrasion resistance.
It has poorer fatigue resistance.
Heat resistance is better than natural rubber.
Low temperature flexibility and tensile strength are less than that of natural rubber.
1.2.8) Chemical used
Chemical intermediates manufactured from butadiene include adiponitrile and chloroprene. Adiponitrile is used to make nylon fibres and polymers. Chloroprene is the monomer to make polychloroprene, better known as Neoprene, which has a wide variety of uses such as wet suits, electrical insulation, car fan belts, gaskets, hoses, corrosion-resistant coatings and adhesives.[ Anonymous, (February 2009),Butadiene Uses and Market Data]
1.2.9) Other applications
Elastomers, 61% (styrene-butadiene rubber (SBR), 32%; polybutadiene, 23%; polychloroprene, 4%; nitrile, 2 percent); styrene-butadiene latex, 12%; adiponitrile for HMDA, 11%; ABS resins, 5 percent; miscellaneous, 11%
Anonymous, (November 1996),Locating and Estimating Air Emissons From Source]
Other polymers made from butadiene include styrene-butadiene (SB) copolymer latex, which is used in paper coatings, carpet back coatings, foam mattresses and adhesives. Styrene-butadiene block copolymers have many applications ranging from asphalt modifiers in road and roofing construction to adhesives, footwear and toys.
Nitrile rubbers, made by the copolymerisation of acrylonitrile with butadiene, are used mainly in the manufacture of hoses, gasket seals and fuel lines for the automobile industry as well as in gloves and footwear.
1.3. Problem Statement
Butadiene is one of highly demanded products in petrochemical industry. For many years, its production rate has been increasing. The current production of butadiene is about 7,000,000 ton per year in USA, Western Europe and Eastern Asia only, and it does not satisfy the market needs, since yearly increase in demand is predicted to be 3.9%, whereas increase of production rate is 2-3% only. The price of the product during 2000 increased by 25%. Butadiene is produced using n-butane as a raw material in a two stage Gudry vacuum dehydrogenation process. The output of butadiene in this process is usually about 12%. The project presents the extremely effective solution for production butadiene – the catalyst that makes it possible to increase output of butadiene from 12 to 25%.[DR. Talishinsky, (1996),Butadiene production]
Besides elastomers will continue to be the largest consumer of butadiene and should maintain their position of 61 percent of total consumption. However, they are mature products that are heavily reliant on the automotive industry. Adiponitrile/ hexamethylenediamine (HMDA), styrene-butadiene (SB) copolymer latex, acrylonitrile-butadiene-styrene (ABS) resins, styrenic block copolymers and other smaller polymer applications will grow faster than the elastomers (excluding polybutadiene), but they each account for only 5-10% of the total butadiene market. With a projected negative average annual growth of -1.7 during 2000-2004, the total market for butadiene in 2004 will reach 5.1 billion pounds, or about about what it was in 1998. This takes into account the big hit in demand in 2001. [Lynne M.Miller, (Dec 1978),Investigate of Selected Potential Environmental Contaminants : Butadiene and its Oligomers,]
So to recover the quality and maintain the production cause of the high of demand in Malaysia and the entire world, the selected of this plant design
research title are very suitable.
1.4. Objective and Scope
The objective of this research of plant design is to increase the production of butadiene with efficient way and to bear an amount of demanding production especially in Malaysia with the scope of this research are:-
i. To design the plan based on demand of production ii. To develop a suitable business in Malaysia
1.5) MARKET SURVEY
1.5.1) Global Situation
The Global production and consumption of butadiene in 2008 were approximately 10.6 million metric tons and 11.1 million metric tons, respectively. Global capacity utilization in 2008 was 88%. Global butadiene consumption is estimated to have increased by almost 2% in 2008, and is expected to average growth of 3.8% per year from 2008 to 2013, slowing to 2.3% per year from 2013 to 2018. Global utilization rates are expected to be in the 90s. [Anonymous, (January 2010),Butadiene]
Styrene butadiene rubber (solid & latex) accounted for more than 30% of global butadiene consumption in 2008, followed by polybutadiene rubber, for around 25%. Other applications for butadiene include manufacture of styrenic copolymers, ABS resins, SB latex, nitrile rubber, and adiponitrile/HMDA.
The following pie chart shows world consumption of butadiene by end use: [Anonymous, (January 2010),Butadiene]
From the figure 1.4, it’s shown that butadiene demand is concentrated in its use in the manufacture of styrene butadiene rubber (SBR) solid and latex (34.7%), polybutadiene rubber (24.9%), ABS resins (10.2%), SB copolymer latex (9.4%) and other consumptions about 20.9%.
Figure 1.4: World consumption of Butadiene
Table 1.1.0: World Butadiene Supply/Demand Balance (1999-2005)
Demand for butadiene in the production of ABS resins will see the highest average annual rate growth for all derivatives in the increase in total tons of butadiene consumed. Demand of butadiene in this application will increase by more than 500,000 tons during the period. Global demand for butadiene will increase at an average annual rate of 3.9% during the period from 2001-2006 percent and will outpace capacity additions. This rate is higher than the
compounded annual rate of 2.7% from 1996-2001 due to the global decline in demand that occurred in 2001 following the global economic slowdown.[ Jorg Wutke, (1996),The petrochemical Industry in China]
It’s expected that, in 2008 through 2012 period will experience a butadiene demand growth rate of just under 3.5 percent per year, slightly higher than the 3.2 percent annual rate experienced over the past five years. Global demand for butadiene consumed into ABS resin production is estimated to grow at a high annual rate of around five percent, due to heavy use of thermoplastics in the manufacture of computer equipment and other appliances, mainly in China. Butadiene based nylon production, through adiponitrile, will also grow at about five percent per year. However, worldwide demand for butadiene in its largest end use sector, the production of commodity-based synthetic rubber and latex, is anticipated to average around 3% per year.[ Anonymous, (January,14,2008), CMAI Completes 2008 World Butadiene Analysis]
1.5.1.1)Styrene Butadiene Rubber (SBR) Demand
The tyre industry consumes 75 percent of the SBR produced globally followed by the mechanical rubber goods/automotive parts applications (19 percent of the market). Footwear accounts for only around six percent of the SBR market. The main use of SBR is in the manufacture of tyre tread, and consumption is forecast to develop in line with the automotive sector.
1. The production of auto tyres is increasingly competitive and cost sensitive. Consequently, the manufacture of tyres and other rubber goods has tended
to migrate to lower labour cost areas, depressing market growth in developed regions such as Western Europe, the United States and Japan. Exports of finished rubber goods, primarily tyres, from regions such as China to the United States and Europe have increased dramatically over the last five years, leading to the closure of a number of tyre plants in the importing regions. Flourishing automotive sectors in China, India, and Thailand have also increased demand in the Asia Pacific region. [Anonymous, (2008), Butadiene Derivatives Impacted by Automotive Crisis]
1.5.1.2 Butadiene Rubber (BR)
Approximately two-thirds of BR is consumed in tyre production, with a further quarter used as an impact modifier in high impact polystyrene (HIPS) production. Other applications consume only around eight percent of the BR market. As the main use of BR is in the manufacture of tyres, BR consumption is forecast to increase in line with the automotive sector.
Asia Pacific, North America and Western Europe are the major consuming regions for BR, with total consumption in these three regions accounting for more than 80 percent of the global total. China has surpassed the United States to become the largest consumer of BR in 2007. The combination of new tyre manufacturing and high impact polystyrene (HIPS) capacities in China has boosted demand for BR while some rationalisation of both capacities was seen in the United States.[ Anonymous, (1996), Butadiene rubber]
1.5.1.3 Acrylonitrile Butadiene Styrene (ABS)
Global ABS demand has been under pressure from inter-polymer competition, especially from polypropylene and lately polystyrene, which is competing particularly at the lower specification end of the automotive sector. Recent development in high gloss polystyrene is a new threat for ABS for decorative parts. However, ABS remains the material of choice in most applications in the key electronics/electrical appliance sector, due to its mechanical properties, high gloss and processability.[ Anonymous, (November 1996),Butadiene Styrene]
Although ABS consumption is forecast to grow at slower rates over 2009-2018 after the recent economic downturn, it will be one of the key drivers for styrene market growth during the recovery of the economy, with long term sustainable growth supported by the electrical appliance and automotive sectors. Asia Pacific, particularly China will remain the largest consuming region with an increasing proportion of the global consumption. Central Europe is expected to grow to balance the slowdown in the Western Europe.
Figure 1.7: Global ABS Capacity
In 2008, SBR is the largest end use of butadiene, accounting for slightly less than one-third of total demand, followed by BR and SBL respectively. ABS, hexamethylenediamine (adipic acid) HMDA and other butadiene uses made up the remaining demand, accounting for 30 percent in total. Butadiene consumption is driven to a great extent by the automotive industry, which tends to give a very volatile growth pattern. Historically, BR grew faster than SBR, but this will change in the forecast due principally to the slow growth in HIPS market. Despite a freefall in the ABS sector last year along with electronics and automotive industries, ABS is expected to recover and continues to grow at high rates. Due to a cost advantage over the acrylonitrile process, demand into HMDA towards butadiene will also grow rapidly as new plants start up in the United States and China. On the other hand, the growth of the SBL sector is forecast to moderate as a result of more efficient use in paper and carpet industries. [Anonymous, (2007),Product overview and market projection of emerging bio]
Figure 1.8: Global Butadiene Capacity
Butadiene extraction capacity is concentrated in the major naphtha cracking regions of Asia Pacific, North America and Western Europe. The development of ethylene capacity based on heavier feedstocks in the Middle East will increase butadiene capacity there, although the region is destined to remain small in terms of overall production. Capacity in Eastern Europe is expected to remain fairly flat as ethylene capacity in the region remains in excess of demand, and is not expected to increase significantly.[ Anonymous, (2009),Butadiene Market Dynamics]
Figure 1.9: Global Butadiene Consumption, Operating Rate and Capacity
Global butadiene operating rates remain at well above average levels, but are expected to decline towards a trough in 2011 as major capacity additions are made during the forecast period of low demand growth. The increasing proportion of liquids based cracker developments will increase the availability of mixed C 4 feedstock for butadiene extraction at a rate greater than that of butadiene demand growth. This is expected to result in a greater proportion of mixed C 4 hydrogenation and co-cracking rather than over expansion of butadiene extraction capacity. The limited amount of naphtha cracker capacity expansion in North America and Western Europe will govern the level of butadiene capacity development in these areas. No new derivatives will be based in areas where there is no additional butadiene availability, leading to a gradual concentration of activity in butadiene and derivatives in Asia. [Anonymous, (2009),Butadiene Market Dynamics]
Year Price ($/Pound) 2004 0.30 2005 0.26 2006 0.544 2007 0.735 2008 1.360 2009 0.428
Table 1.1.1: World Butadiene Prices (2004-2009)
Year Demand (-000-Metric Tons) 1999 7,880 2000 8,340 2001 8,634 2002 8,937 2003 9,229 2004 9,507 2005 9,810 2006 10,430 2007 10,878 2008 11,513
Table 1.1.2: World Demand toward Butadiene
According to the figure 1.4.5, world demand towards butadiene was slowly increased from 1999 to 2008. In 2009, global butadiene demand is expected to grow at a pace lower than the 3.2 percent annual rate experienced over the past five years. For example, the outlook for worldwide butadiene in its largest end use sector, the production of commodity based synthetic rubber and latex, is anticipated to only average around 2 percent per year. A slowing global economy is also causing slower demand for rubber goods, especially in the automotive sector. Global butadiene growth has averaged 3.3 percent per year from 1995-2006, but is expected to average only 3.1 percent over 2006-2015. Global consumption of butadiene is expected to increase from 10 million tons in 2006 to 13 million tons by 2015.[ Anonymous, (2008),Basic Material: Global Insights]
From figure 1.4.4, the global prices of butadiene were rapidly increasing from 2004 to 2008 but the price was drastically decreased in 2009. Actually, the global economic culture and oil prices were affecting the prices of butadiene in the market. We believe that the global prices rhythm of butadiene will increased according to the report that said the global economic will became stable at the end of 2010. The political instability especially in the Middle East (Iraq and Iran) will cause the increasing of global oil prices. So, we assumed that when the oil prices increase, the global prices of butadiene will increased too.
1.5.2 Asia Pacific Situation
The Asian market has been particularly active in building new capacity of butadiene and butadiene derivatives due to the ongoing development of automotive and tyre production in the region. The relocation of automotive industries increased synthetic rubber demand through tyre production, while both ABS and HMDA will benefit from plastics demand in the Asian automotive
sector. Additional global demand for butadiene in recent years was entirely focussed in Asia Pacific where significant new derivatives capacity built up, particularly in China and South Korea. In the outlook, the share of Asia Pacific demand will grow further from 45 percent in 2008 to 53 percent in 2015.
Demand in Asia Pacific accounts for 41 percent of the global total, and the proportion is forecast to increase. The growth in demand in Asia is driven by increasing availability, and the rapid growth in demand in derivatives to supply the booming Asian manufacturing sector.[ Anonymous, (2008),Basic Material: Global Insights]
The markets for butadiene have emerged from a long period of oversupply, leading to record prices and margins in 2006. Butadiene prices broke the $1,500 per ton level in Asia in late 2006, almost six times the lowest prices seen in the late 1990s. At the same time, margins for West European producers reached over $400 per ton, despite the prevailing high feedstock prices. The current high global operating rates are set to last through 2007 and 2008, before dropping off due to major capacity additions.
The Asian market has been particularly active for butadiene due to the ongoing development of automotive and tyre production in the region which drives demand, and the major steam cracker developments which drive supply. The Asia Pacific region has accounted for over half of global capacity and demand growth over the past five years, and will account for three quarters over 2007-2011.
Major steam cracker developments in Asia will provide more mixed C4s for butadiene production, leading to a decrease in operating rates. In the long term, the growth of ethylene production, and therefore the availability of C4s, will exceed demand growth for butadiene, leading to increased reprocessing of steam cracker C4s. Countries such as China are expected to extract enough butadiene to serve their own derivative requirements, and hydrogenate then recycle the remainder back to the steam cracker.[ Anonymous, (2008),Basic Material: Global Insights]
The operating rates will remain above 85% until 2009, when major capacity additions and slower demand growth will cause a decline towards a trough in 2011. New capacity developments are focussed on conventional extraction from steam cracker mixed C4 streams. The current high margins on butane dehydrogenation are expected to be temporary and not likely to encourage new investment in this technology. The tendency towards heavier cracker slates in the Middle East is increasing the availability of steam cracker C4s for butadiene and derivatives. The scale however remains small relative to expansions in Asia . While currently growing rapidly from a small base, the Middle East is unlikely to build a major export position for butadiene and derivatives as it has in the ethylene chain.[ Anonymous, (2008),Basic Material: Global Insights]
1.5.2.1 Butadiene Market in China
With the increase of domestic butadiene production capacity, China's butadiene supply will basically meet the rising demand in the coming four years, according to industry experts.With large scale development of the ethylene industry, enterprises under the aegis of China's two oil giants PetroChina and Sinopec are swarming to build or expand butadiene production facilities to
produce butadiene, which is in great demand on the domestic market. It is predicted that China’s butadiene production capacity is expected to reach 2.7 million tons by 2011. [Anonymous, (2008),Management Discussions]
China had 18 butadiene producers and 26 sets of butadiene production facilities with an annual production capacity totaling 1.614 million tons by May 2007, accounting for 13.5 per cent of the world's total. Last year, it produced 1.153 million tons of butadiene, an increase of 15.78 per cent over 2005. Its butadiene output grew at an average annual rate of 12.3 per cent in 2001-2006. However, its current output cannot satisfy the domestic demand. It has to import butadiene in bulk. With some production facilities newly built or expanded, the import volume has declined moderately, from 195,900 tons in 2004 to 147,200 tons in 2005 and 89,200 tons in 2006. With the rapid development of synthetic rubber industry, the main consumer of butadiene, China's apparent butadiene consumption has kept growing in recent years, from 782,500 tons in 2001 to 1.0353 million tons in 2004 and 1.2153 million tons in 2006. It is predicted that the consumption will grow 8.7 per cent annually from 2006 to 2011, topping 1.7 million tons in 2011.[ Anonymous, (Nov 2008),Production from China]
1.5.3 Malaysia Situation
Malaysia has a well-developed oil and gas sector and a growing petrochemical industry. The petrochemical industry is an important sector in Malaysia with investments totaling US$7.4 billion in 2004 and US$6.9 billion in 2007. From being an importer of petrochemicals, Malaysia is today an exporter of major petrochemicals product. A wide range of petrochemicals are produced in Malaysia such as olefins, polyolefin, aromatics, ethylene oxides, glycols,
oxo-alcohols, exthoxylates, acrylic acid, phthalic anhydride, acetic acid, styrene monomer, polystyrene, ethyl benzene, vinyl chloride monomer and polyvinyl chloride.[ Anonymous, (2009),Butadiene Market Dynamics]
The rapid growth of the industry is mainly attributed to the availability of oil and gas as feedstock, a well-developed infrastructure, a strong base of supporting services, the country's cost competitiveness, as well as Malaysia's strategic location within ASEAN and its close proximity to major markets in the Asia Pacific Region. Malaysia has the world's 14th largest natural gas reserves and 23rd largest crude oil reserves. In 2008, Malaysia produced 5,891 million standard cubic feet per day of natural gas and 691,600 barrels of oil equivalent per day of crude oil. Malaysia also has the world's largest production facility at a single location of liquefied natural gas with production capacity of 23 million metric tonne per year.[ Anonymous, (2009),Butadiene Market Dynamics]
The long term reliability and security of gas supply ensures the sustainable development of the country's petrochemical industry. The existence of a trans-peninsular gas transmission pipeline system and six gas processing plants, has resulted in a ready supply of gas to the industry. To complement the existing gas reserves and to ensure further security of gas supply, Malaysia has forged partnerships with other ASEAN members for the supply of gas such as Vietnam, Indonesia and the Malaysia-Thailand Joint Development Area (JDA). In addition, gas supply will be further enhanced with the implementation of the ASEAN gas grid, a venture to make gas available to all the 10 ASEAN countries. With the full implementation of AFTA, petrochemical manufacturers in Malaysia will benefit from a single market. Manufacturers based in Malaysia will also benefit from the access to a much larger Asia Pacific market. With China being a net importer of petrochemicals, Malaysia's 'early harvest' Free Trade Agreement with China will
open up new business opportunities for petrochemicals manufacturers in Malaysia.[ Anonymous, (2009),Butadiene Market Dynamics]
The presence of world renowned petrochemical companies, such as Dow Chemical, BP, Shell, BASF, Eastman Chemicals, Toray, Mitsubishi, Idemitsu, Polyplastics, Kaneka, Dairen and West Lake Chemical speaks clearly of Malaysia's potential as an investment location for petrochemical industries. Most of these companies are working in collaboration with Malaysia's national petroleum company, PETRONAS. Three major petrochemical zones have been established in Kertih, Terengganu; Gebeng, Pahang; and Pasir Gudang/Tanjung Langsat, Johor. Each zone is an integrated complex with crackers, syngas and aromatics facilities to produce feedstocks for downstream products. There are also other petrochemical plants in Malaysia such as the ammonia and urea plants in Bintulu, Sarawak and Gurun, Kedah; acrylonitrile butadiene styrene plant in Pulau Pinang; methanol plant in Labuan and the nitrile-butadiene rubber plant in Kluang, Johor.[ Anonymous, (2009),Butadiene Market Dynamics]
1.6) SCREENING OF SYNTHESIS ROUTE IN PRODUCTION OF BUTADIENE
Butadiene is produced commercially by three processes:
Steam Cracking of Paraffinic Hydrocarbons
Catalytic Dehydrogenation of n-Butane and n-Butene (the Houdry process). Oxidative Dehydrogenation of n-Butene (the Oxo-D or O-X-D process).
1.6.1) Butadiene Production via Steam Cracking of Paraffinic Hydrocarbons
Figure 1.12: Typical Olefin Plant
In this process, butadiene is a co product in the manufacture of ethylene (the ethylene co-product process).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 1.1 depicts a flow chart for a typical olefins plant.
The flow path of the C4 components (including butadiene) is indicated by bold [red] lines.
The indicated feed stocks (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.[ Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
While some olefins plant designs will accommodate any of the listed feed stocks, many olefins plants process only Natural Gas Liquids (NGLs) such as ethane, propane and sometimes butane. The mixes of feed stocks, the conditions at which the feed stocks 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. Olefins plants generally produce crude butadiene streams that contain very few C3 and C5 components, as shown by the analysis found in Table 1.1. The composition of the crude butadiene stream also can be altered via recycle blending of various product streams. For example, when finished butadiene streams (99+ wt% pure) do not meet commercial specifications, they are often combined with crude butadiene streams in order to recover the butadiene. In this situation, the resulting stream may not fall into the example range. Generally, crude butadiene is stored as a liquid under pressure in a pressure products sphere.[Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
Table1.1.3: Example of a Crude Butadiene Analysis
1.6.2) Butadiene Production via Catalytic Dehydrogenation of 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 1.13. 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.[Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
Figure 1.13: Catadiene Process Plant
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.
1.6.3) Butadiene Production via Oxidative Dehydrogenation of 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 feed stocks. 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 selective can range from 70-90%, making it unnecessary to recover and recycle feedstock. (Yield losses can produce the CO2.) In the Oxo-D process shown in Figure 1.3, 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.[Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
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, and then it is sent to a purification system to recover the butadiene product.[Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
Figure 1.14: Oxidative Dehydrogenation Process
1.6.4) Butadiene Recovery from Crude Butadiene Streams Via Extractive Distillation
Since the boiling points of the various C4 components are so close to each other, separation via simple distillation does not currently suffice to adequately separate the components; therefore, extractive distillation is used. Several design options are available, including those listed in Table 1.2. Inclusion here is not intended as an endorsement. These processes involve one or two extractive distillation steps followed by one or two distillation steps. The number of extraction and/or distillation steps can be reduced to one by including an acetylene hydrogenation step.[Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
Table 1.1.4: Major Butadiene Recovery Process
1.6.5) Butadiene Purification via Acetylene Hydrogenation and Extractive Distillation Using MOPN/Furfural Solvent
This process contains four sections: 1) acetylene hydrogenation, 2) extractive distillation, 3) butadiene purification, and 4) solvent purification.
The objective of the acetylene hydrogenation section is to hydrogenate C4 acetylenes that could otherwise contaminate the butadiene product. This is achieved using a liquid phase reactor system. Butadiene-dimers and trimers formed in the reactor are removed via distillation in the green oil column located just downstream of the reactor. The green oil column overhead stream is fed to the extractive distillation section. The function of the extractive distillation section is to separate the C4 hydrocarbon stream into a butane/isobutene/trans-butene-2 stream (C4 Raffinate 1) and a butadiene/cis-butane/isobutene/trans-butene-2 stream via extractive distillation and solvent stripping. The green oil column overhead stream is vaporized then fed to the lower portion of the extraction column where the vapors are counter currently contacted with the aqueous methoxy-proprio-nitrile (MOPN)/furfural solvent which are fed into the top of the column. Butane and the less soluble butenes are concentrated and removed in the overhead stream.
The butadiene/cis-butene-2 rich solvent from the bottom of the extraction column are fed to the extract stripper column, where butadiene, cis-butene-2 and acetylenes (ppm level) are stripped overhead. The extract stripper column overhead stream is used to feed the butadiene purification column where butadiene is concentrated in the overhead product. Then the remaining butene-2 and heavier components are drawn from the bottom of the column and recycled to the olefins plant cracking furnaces. The purpose of the solvent purification section is to remove impurities from the lean solvent. The system consists of two evaporators, a stripping column and a solvent settling drum which are used to remove furfural-butadiene polymer, acrylonitrile-butadiene codimer, and vinylcyclohexene compounds. [Anonymous, (2002),Butadiene product Stewardship Guidance Manual]
Figure 1.15: Process A- Acetylene Hydrogenation/Extractive Distillation Using MOPN/Furfural
1.6.6) Extractive and Conventional Distillation Process Using NMP Solvent
This process, licensed by BASF and illustrated in Figure 1.6, is a combination of extractive and conventional distillation. The extractive distillation uses n-methylpyrrolidone (NMP) as the solvent. The highest temperature is approximately 300 °F and the maximum pressure is approximately 100 psig (7 bars g).
The evaporated C4 cut is fed to the extractive distillation section where in the first stage the butanes and the butenes are separated from the more soluble 1,3-butadiene, 1,2-butadiene, C4 acetylenes, propyne and the C5 hydrocarbons. The loaded solvent is degassed in a steam heated column where the acetylenes are withdrawn as a side stream and are fed to a washer where the NMP is recovered.
Crude butadiene leaves the extractive distillation section at the top of the second stage and is then fed to the propyne distillation column where propyne (methyl-acetylene) is removed overhead. The bottoms product containing the 1,3-butadiene, 1,2-butadiene and the C5 hydrocarbons is then distilled in the butadiene column. Generally, 1,3-butadiene with a purity of >99.6% by weight leaves the top of the butadiene column. The column bottoms stream usually contains 1,2-butadiene and heavier hydrocarbons.
The crude butadiene, the top of the propyne column, and the purified butadiene are typically inhibited with tertiary butyl catechol (TBC) or with other compounds. Sodium nitrite can be used as an inhibitor during extractive distillation. The waste hydrocarbon streams can be diluted with naphtha and used as supplemental feedstock for the olefins plant.[ Anonymous, (November 1996),Produce of Butadiene]
Figure 1.16: Process B- Extractive and Conventional Distillation Using NMP
1.6.7) Dimethylformamide (DMF) Solvent Extraction Process
This process, licensed by Nippon Zeon, consists of four sections: 1) first extractive distillation; 2) second extractive distillation; 3) butadiene purification; and 4) solvent purification. SeeFigure 1.7. In the first section of the plant, the hydrocarbon feed (C4 fraction) and the DMF solvent are fed to the first extractive distillation column, where the C4 stream is separated into two fractions:
1. the C4 raffinate 1 overhead product, which contains less soluble components (butane/butene); and,
2. The bottoms product, which contains the DMF solvent rich in butadiene/acetylene components which are the more soluble components.
At this stage, the C4 raffinate 1 product stream is available for downstream processing (MTBE, polyisobutylene, alkylation). The butadiene/acetylene rich solvent is fed to the first stripper column where the butadiene/acetylenes are stripped from the solvent and proceed overhead to the second extractive distillation section. The lean solvent from the stripper is cooled via heat recovery prior to being sent back to the extractor. In the second extractive distillation section, the butadiene/acetylene stream from the first section also is separated into two fractions, again using DMF as the solvent:[ Anonymous, (November 2006),Production of Butadiene]
1) butadiene/methyl acetylene rich overhead fraction; and,
2) bottoms fraction, containing the DMF solvent rich in vinyl acetylene which is more soluble in the DMF solvent than is butadiene or methyl acetylene.
The butadiene/methyl acetylene rich overhead fraction is sent on to the butadiene purification section of the process where the remaining acetylenes are removed using two distillation columns and a pure 1, 3-butadiene product stream is produced. The bottoms fraction from the second extractive distillation is fed to a stripper column where a vinyl acetylene rich stream is stripped from the solvent and used for fuel.
Since the DMF solvent is continuously circulated to the first and second extractive distillation columns, butadiene dimer, tar, and any water from the C4 feed stream tend to increase in concentration, thereby decreasing the effectiveness of the solvent. Therefore a part of the solvent is continuously passed to the solvent purification section of the plant to remove these impurities.
Figure 1.17: Process C- DMF Solvent Extraction Process
1.6.8) Aqueous Separation and Acetonitrile (ACN) Extraction
In this process, licensed by Shell, the hydrocarbon feed (C4 fraction) is routed to an extractive distillation system. The separation is achieved in an aqueous solvent environment, where the top product contains the butanes/butylenes and the bottoms stream contains the butadiene and acetylenes. Acetonitrile (ACN) is used as the extraction solvent. As illustrated in Figure 1.8, the butadiene is then stripped from the extraction solvent and may be fed to a topping column where residual light ends (primarily methyl acetylene) are rejected. Heavier acetylenes such as vinyl acetylene and ethyl acetylene are rejected as a side stream from the solvent stripping operation. Bottoms product from the topping column can be fed to a postfractionator where residual olefins (cis-2/trans-2 butene) and remaining trace heavy ends (vinyl, ethyl and heavier acetylenes, 1,2-butadiene, dimer, C5’s and heavier) are rejected to the bottoms.
The overhead butadiene product is chilled and passed through a coalescer to remove entrainedwater before being sent to the rundown tanks in the tank farm. Tertiary butyl catechol (TBC) is added to the butadiene to inhibit the formation of peroxides. It is also common to use an in process inhibitor that is removed prior to the addition of TBC.
Hydrocarbon streams exiting the process can be washed with water for the removal of ACN.The recovered solvent can be concentrated and returned to the extraction section.[ Anonymous, (November 2006),Production of Butadiene]
Figure 1.18: Process D - Aqueous Separation and ACN Extraction Process
1.7) JUSTIFICATION OF PROCESS CHOSEN
PRODUCTION OF CRUDE BUTADIENE
1 2 3 Temperature 1450-1525 °F (790-830 °C) 1100-1260 °F (600-680 °C) 930-1110 °F (500-600 °C).
Pressure 98-118 kPa 15-20 kPa
Reaction (exo/endo)
endothermic endothermic exothermic
% of butadiene 2-16% 30% - 50% 70-90%
Side products hydrogen, ethylene,
propylene, fuel gas, fuel oil
_
Raw material Ethane, propane, butane, naphtha, gas oil
n-butane/n-Butenes n-Butenes
catalysts chromium/alumina bismuth
molybdate
Table 1.1.5: Properties of Crude Butadiene
Among the choices for implementing the production of butadiene (polymer grade) from C4 fractions, we have chosen to do a coupling of catalytic dehydrogenation of n-butane and n-butene (the Houdry process) and oxidative dehydrogenation of n-butene (the Oxo-D or O-X-D process).
We have chosen this route because the coupling of the non oxidative catalytic dehydrogenation with the oxidative dehydrogenation of the n-butenes
formed provides a very much higher yield of butadiene based on n-butane used. The non oxidative dehydrogenation can also be operated in a gentler manner. This coupling process features particularly effective utilization of the raw materials. Thus, losses of the n-butane raw material are minimized by recycling unconverted n-butane into the dehydrogenation. The isomerization of 2-butene to 1-butene also yield 1-butene as the product of value. So because of the coupling process method, we get 1-butene as our byproduct after butadiene as a major production.
For our by product, 1-butene is a linear alpha olefin (alkene), produced either by separation from crude C4 refinery streams or from the reaction of ethylene. It is distilled to give a very high purity product.[ Anonymous, (2007),Butadiene Market Demand]
Butene-1 can be produced directly from C4 cracking and also by extraction from C4's mixtures out of ethylene crackers. It is used as a copolymer in polyethylene alkylates gasoline, polybutenes, butadiene; as intermediates for C4 and C5 aldehydes, alcohols and other derivatives; and in the production of maleic unhydride by catalytic oxidation.
Demand for 1-butene also has a big contribution in chemical area, like Japan’s chemical markets for 1-butenes will grow strongly and for isobutylene very slowly during 2007–2012. Since August 2004, 1-butene demand for propylene production via butylene metathesis quadrupled to 2007, but will slow over the forecast period.[ Anonymous, (2007),Butadiene Market Demand]
While for application for 1-butene is used in the manufacture of a variety of other chemical products. It fills an important role in the production of materials such as linear low density polyethylene (LLDPE). The co-polymerisation of ethylene and 1-butene produces a form of polyethylene that is more flexible and more resilient. 1-butene can also help to create a more versatile range of
polypropylene resins. It is also used in the production of polybutene, butylene oxide and in the C4 solvents secondary butyl alcohol (SBA) and methyl ethyl ketone (MEK).
1.8) SEPARATION OF BUTADIENE BY EXTRACTIVE
DISTILLATION
The C4 product gas stream is separated by means of extractive distillation into a stream that consisting substantially of n-butane and 2-butene and a product stream which is butadiene. To this end, C4 product gas stream is contacted in an extraction zone with an extractant, preferably an N-methyl-2pyrrolidone (NMP)/water mixture. Suitable extractants are butyrolactone, nitriles such as acetonitrile, propionitrile, methoxypropionitrile, ketones such as acetone, furfural, N-alkyl-substituted cyclic amides (lactams) such as N-alkylpyrrolidones, especially NMP. In general, alkyl-substituted lower aliphatic amides or N-alkyl-substituted cyclic arnides are used.[ Anonymous, (1996),Process of Butadiene production]
The effects of the solvents used will be taken into consideration in the comparison for the separation of C4 product to butadiene.
Solvent Hazard
Identification Effect
methoxy-proprio-nitrile
(MOPN) Toxic fumes of acrylonitrile and methanol may be released. Uncontrolled burning may also result in the release of highly toxic hydrogen cyanide (HCN) vapours.
n-methyl-2pyrrolidone (NMP) Stable, but decomposes upon exposure to light.
Combustible Dimethylformamide (DMF) Hazardous
DMF has been linked to cancer in humans, and it is thought to cause birth defects
Acetonitrile (ACN) Toxic and flammable.
It is metabolized into hydrogen cyanide and thiocyanate
Table 1.1.6: Effects of the each solvents
It is noticed that all types of solvents used are hazardous and toxic. MOPN and ACN are unfavourable in terms of environmental friendly as both of these solvents will metabolize into hydrogen cyanide (HCN), which causes threat not only to human health, but also environment. Thus, NMP is the most acceptable solvent to be used in the process as it causes least harm to the environment.
Therefore Extractive distillation process by using aqueous n-methyl-2-pyrrolidone (NMP) is the most environmental friendly method to be used as the solvent (NMP) causes less harm to the environment and provides the process with
1.9) SITE SELECTION & PLAN LAYOUT
There are some factors that should be considered in selecting the suitable site. This is very important because the characteristics of a site location will have a market effect on the success or otherwise of a commercial venture. The choice of the final site should be based on a complete survey of the advantages of various geographical areas, in addition to the advantages and disadvantages of available industrial estates.
There are locations designated which have potential to fulfill all the criterion shows above. The locations is Kerteh Industrial Estate, Terengganu
1.9.1) Plant Location
The basic site selection process takes account the criteria of the economic geography of the area in which the plant site is placed. Several important criteria or factors should be considered, such as:
Figure 1.19: Map of Plant Location
1.9.1.1) Land price
The first factor to consider is the land price. The cost of a land depends on the location of the property and may vary between rural district and a highly industrialized area. [49]
1.9.1.2) Raw Materials
This is particularly important if large volumes of raw materials are required by plant. The availability of raw material is important due to its location from plant, transportation and its purity to ensure the least cost is needed.
1.9.1.3) Transportation
Water, railroads and highways are the common means of transportation used by major industrial concerns. These types of connection needed to ensure the distribution of the product is optimize.
1.9.1.4) Water Supply
The plant should be located where water supply is available for the purposes of cooling, washing, steam generation and as a raw material. Temperature, mineral content, purification (treatment) and cost of water ought to be considered.
1.9.1.5) Energy supply
The location of a plant site should be near to hydroelectric installations if the plant is using electrolytic process. The local cost of power can help to determine whether power should be purchased of self-generated.
1.9.1.6) Labors
Type and supply of labors available in the vicinity of a proposed plant site must be examined. Consideration should be given to prevailing pay scales and restrictions on number of working hours per week
1.9.1.7) Waste management
The site selected for a plant should have adequate capacity and facilities for correct waste disposal. In choosing a plant site, the permissible tolerance levels for various methods of waste disposal should be considered carefully, and attention should be given to potential requirements for additional waste treatment facilities.[ Anonymous, (November 1996),Produce of Butadiene, Website]
1.9.1.8.1 Availability of raw materials
Location/ Characteristics
Kerteh Industrial Estate, Terengganu
Land Price RM 0.18 -RM5.60 per ft 2
Sources of Raw Material
(Natural gas
-Petronas LNG Sdn Bhd at Kerteh - Reserved natural gas until 2007 (53 trillion cubic feet)
Transportation East Coast highway Kemaman Port
Water Supply Terengganu Water Company (SATU Electricity Supply Paka power plant
Labor - UMP, UMT, UTM, UiTM, TATIUC<
POLISAS Area Available 1184.2 hectares Preferred Industry Type Chemical
Nearest town -15 km from Kemaman
-160 km from Kuantan -220 km from Kuala Lumpur
Waste management Monthly charges vary for disposal of toxic waste carried out by Kualiti Alam according to the type and quantity of waste.
1.9.1.8.2 Selected Site
Industrial land is available in all districts in the form of developed, semi developed as well as raw land. Terengganu’s industrial land is among the cheapest in Malaysia, at RM0.18 - RM5.60 or (US$0.06 - $1.75 per square foot) compared to other states, where land sells from lows of RM2.00 - RM4.50 psf to highs of RM18.00 - RM22.00 psf.
The location very near with Kemaman and Kuantan town provided local community factors such as banking, medical, security, housing and entertainment
Our plant needs the supplier to supply major raw material that is C4
For delivering process of ammonia, Kerteh can be link to Kuala Lumpur by East Coast highway which can reduce traveling time from four hours to only two hours by truck also can be export by ships through Kemaman Port
For the manpower or labor, UMP,TATIUC and POLISAS with quality educational level and other technical schools can provide skilled and semi skilled workers to operate and handle our plant
Others universities such as UM, UTM, UTP, UPM, UKM and UiTM also can provide many graduate students to work in our plant
Terengganu employs an integrated environmentally friendly waste management system for industrial wastes that meets international best practices.[ Anonymous, (November 1996),Produce of Butadiene, Website]
Admininstration Building Butadiene Plant N-Butane Butadiene N-Butane Butadiene Cooling Tower Utilities Area Waste treatment Mosque
Master Evacuation Area Control Room
Loading / Unloading Area
Fire Station Fire Water Tank Laboratory Fire Water Tank Workshop Cafeteria Mosque Cafeteria Post Guard Figure 1.20: Plant Layout
CHAPTER 2
PROCESS SYNTHESIS AND FLOWSHEETING
2.1 SYNTHESIS OF PROCESS FLOW DIAGRAM
2.1.1 Introduction
Process synthesis and flow sheeting is the most important in plant design. In this chapter, it will cover material and energy balance and simulation by using ASPEN. Generally, the processes that choose in producing butadiene from butane is catalytic dehydrogenation and oxidative dehydrogenation. This route absolutely gives an optimum purity of butadiene. Here, 50 000 MT/yr butadiene from butane will produced.
2.1.2 Process Flow Diagram (PFD)
Process flow diagram in figure 2.1 below described details flow of butadiene process. Basically for the PFD diagram, the major and minor include together except the controller system that explained details in process safety studies. Catalytic dehydrogenation process used 1 basic chemical which is butane and water and air used as a combustion process to remove hydrogen. Then produce 1-butene and 2-butene. For second reaction, used Oxidative
dehydrogenation process to produce 1-butane, 2-butene to butadiene from hydrogen removed. To produce butadiene, there are 6 equipments involved. The equipments are:
a. The Fixed Bed Reactor – Reaction occurs here
b. The NMP solvent recovery system that function to recover the NMP solvent.
c. The distillation for separate light and heavy end which is 1-butane and butane
d. Heat transfer for maintain the temperature in the process
e. Absorption for separate inert gas and C4 hydrocarbon