Continuous development of the hottest polypropylen

2022-08-14
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With the continuous development of polypropylene industry, the world demand for propylene has increased from 15.2 million tons 20 years ago to 51.2 million tons in 2000, with an average annual growth rate of 6.3%. It is predicted that the world propylene demand will further increase to 86million tons by 2010, with an average annual growth rate of about 5.6%; The world propylene production capacity will increase from 59.3 million tons in 2000 to 62 million tons in 2001, 68 million tons in 2002, 74 million tons in 2004 and 82 million tons in 2008. The average annual growth rates of the main derivatives of propylene are: Polypropylene 6.3%, acrylic acid 6%, acrylonitrile 4%, propylene oxide 4%, cumene/phenol 3.8%. Among the photochromic materials of propylene derivatives with reversible changes in color and various physical properties, polypropylene accounts for the largest consumption of propylene, accounting for 57%. The others are: acrylonitrile 11%, carbonyl alcohol 8%, propylene oxide 7%, cumene 6%, acrylic acid 5%, isopropanol 3%, and others 3%

in order to further improve propylene production, production technology will tend to be diversified. On the basis of steam cracking and catalytic cracking as the main sources of propylene, catalytic cracking, propane dehydrogenation, translocation reaction, olefin mutual conversion and methanol to olefin (MTO) processes will be further developed. At present, 66% of propylene in the world comes from the by-product of steam cracking to produce ethylene, and 32% from the fluidization catalyst in refineries. 1. After the transformation, various control parameters can be automatically calibrated; A small amount (about 2%) of by-products from chemical cracking (FCC) production of gasoline and diesel are obtained from propane dehydrogenation and translocation reaction. In the process of steam cracking to produce ethylene, the yield of propylene varies with raw materials and operating conditions. Generally, naphtha, crude diesel oil and propane are used as raw materials to produce ethylene. For each ton of ethylene produced, 0.4 ~ 0.6 tons of propylene are produced by-product; With ethane as raw material, only 0.04 ~ 0.06 tons of propylene can be produced by producing 1 ton of ethylene

the National Institute of materials and chemistry of Japan and four petrochemical companies jointly developed a naphtha cracking process to increase propylene production and reduce energy consumption, which can increase the ratio of propylene to ethylene from the traditional 0.6:1 to 0.7:1. Using lanthanum catalyst supported on molecular sieve in fixed bed, the yield of ethylene and propylene can reach 61%, while that of conventional steam cracking is 50%. The process operation is carried out at 650 ℃ and 0.1M ~ 0.2MPa. Due to the operation at lower temperature, the energy consumption is reduced by about 20%

fluid catalytic cracking technology extended to chemical industry typical fluid catalytic cracking (FCC) unit produces only 0.03 ~ 0.06 tons of propylene per ton of vehicle gasoline. In recent years, FCC has developed a variety of technologies to increase propylene production. The Petrochemical Research Institute of Sinopec has developed the deep catalytic cracking (DCC, also known as catalytic cracking) process. The DCC unit is operated at 538 ℃ ~ 582 ℃ and 10% ~ 30% steam, and molecular sieve catalyst is used to selectively produce propylene and butene. The unit is divided into two types: dcc-1 type, which produces the most propylene, and dcc-2 type, which produces the most isoolefins. The propylene yields are 20.5% and 14.3% respectively. At present, seven DCC units have been put into operation in China and Thailand

UOP adopts the catalytic cracking design of petrofcc, which can increase the production of light olefins, especially propylene, from various raw materials such as gas oil and vacuum residue. UOP designed a dual reaction zone configuration, using two reaction zones and a common regenerator. The yield of propylene can reach 22.8% by this process. The selective group splitting (SCC) process developed by Loomis company adopts high content ZSM-5 molecular sieve catalyst to achieve propylene yield of 16% - 17%, and the naphtha selective circulating cracking technology can also increase propylene yield by 2% - 3%. The maxofin process of Mobil company combines the additive with high ZSM-5 content with the improved FCC technology, and the propylene yield can reach 18%. KBr's sperflex process reaction part is based on KBr's FCC technology, which can convert light hydrocarbons (usually C4 ~ C8) into propylene rich logistics. Propane dehydrogenation technology there are 8 sets of propane dehydrogenation units in the world, with a production capacity of 1.2 million tons/year. It is predicted that 10 new units will be built by 2010 to increase propylene production by 4million tons/year

several units are planned to be built in Malaysia, Saudi Arabia, Spain and Qatar. At present, propane dehydrogenation processes mainly include UOP's oleflex process, Loomis' catofin process, Phillips' star process and Linde's PDH process. Among them, oleflex process and catofin process have been industrialized. Oleflex process unit is composed of reaction area, catalyst continuous regeneration area, product separation and fractionation area, with propylene yield of about 85% and hydrogen yield of 3.6%. Catofin process adopts fixed bed catalytic reactor, and the propane conversion rate is greater than 90%. The investment cost of propane dehydrogenation unit is relatively high, and propane raw materials need to be supplied economically for a long time

translocation reaction technology using translocation reaction technology, ethylene can react with 2-butene to produce two molecules of propylene. When the translocation reaction device is combined with steam cracking, the ratio of propylene to ethylene can be increased to 1.0 ~ 1.25. The triolefins process of Loomis company operates in gas phase at a high temperature of 330 ℃ ~ 400 ℃, using tungsten based catalyst and fixed bed reactor. It has been used in a set of devices at present. This technology will also be used in the large olefin plant jointly invested by BASF fina in 2001. The unit will produce 950000 tons/year of ethylene and 540000 tons/year of propylene. Part of the ethylene produced will be converted into propylene by translocation reaction with butene, which will increase the propylene output by 58%, and finally produce 860000 tons/year of ethylene and 860000 tons/year of propylene

the translocation reaction device increased the ratio of propylene to ethylene to more than 1.0. The disadvantage of translocation reaction technology is that the investment cost is high (but lower than propane dehydrogenation), and it is sensitive to the surface without pits or protruding raw material impurities. In addition, the degradation of high-value ethylene to produce lower value propylene causes waste

olefin mutual conversion process the olefin mutual conversion process (MOI) developed by Mobil adopts selective secondary conversion technology, operates in a fluidized bed reactor, and the catalyst is continuously regenerated. ZSM-5 catalyst is used to make a good combination of acid activity and shape selectivity, which promotes olefin oligomerization, cracking and disproportionation. This process can convert steam pyrolysis C4 and pyrolysis light gasoline into propylene and ethylene, and FCC light naphtha is also a potential raw material

Lurgi company developed a fixed bed catalytic cracking propylar process that converts C4 and C5 olefins into ethylene and propylene. When combined with naphtha steam cracking, the ratio of propylene to ethylene can be increased to 1.0. Typical reaction products include 42% propylene, 13% ethylene and 31% butene. At present, pilot plants have been built. Methanol to propylene process UOP/methanol to olefin (MTO) process of Norsk heidro company has been introduced as a technology for producing ethylene and propylene from natural gas. Methane is converted into syngas, and then the crude methanol produced is used to produce ethylene and propylene through MTO process

under the condition of high propylene, the yield of propylene is 45%, that of ethylene is 34%, and that of butene is 13%. The process adopts the design of fluidized bed reactor and regenerator. Egypt will build the first MTO industrial complex, using natural gas as raw material to produce 320000 tons/year of polyolefins. MTO process combines methanol and polymer units to form a complete natural gas polyolefin unit production line, which will be put into operation in 2003. Lurgi also developed the methanol to propylene (MTP) process, which has been verified in the laboratory under slightly higher pressure (0.13M ~ 0.16mpa) and low temperature (380 ℃ ~ 480 ℃)

there are nearly 50 propylene production enterprises in China, of which 16 are produced by steam cracking, and the rest are refinery propylene manufacturers. By 2005, if the transformation of large and medium-sized ethylene plants in China is completed, and several large joint venture ethylene projects are also completed and put into operation, it is expected that the production capacity of ethylene production (2) for pipelines bonded will reach 8.8 million tons, and 7.92 million tons of ethylene can be produced at an operating rate of 90%. If the production ratio of ethylene to propylene is 1:0.52, the ethylene cracking unit can produce propylene of 4.12 million tons/year. If the cracked propylene output accounts for 61% of the national propylene output, China's Propylene output in 2005 was about 6.73 million tons. By 2005, the growth rate of propylene demand in China will be calculated at 10%. At that time, China's propylene demand will reach 9.53 million tons, and the self-sufficiency rate will be about 70%

at present, the raw materials and processes of propylene industry are developing in the direction of diversification and new technology. FCC technology with high cracking depth and selectivity has been mature and popularized, and other technologies for olefin conversion to propylene are also being developed. Some have achieved practical results, and propane dehydrogenation also has development potential. China should also speed up the development and research of other ways to increase propylene production (such as translocation reaction, propane dehydrogenation, methanol to propylene) to provide technical reserves to meet the growing demand for propylene

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