The latest catalyst is indispensable

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Polyethylene (PE) is the largest variety of general synthetic resin. Because of its low price and good performance, it is widely used in industry, agriculture, packaging and daily life. It plays a decisive role in the plastic industry, so the market demand is huge. According to statistics, the world PE production capacity in 2000 was 56.85 million tons, and the output was 48.28 million tons. It is estimated that the production capacity and output of polyethylene resin will reach 67.86 million tons and 58.36 million tons respectively by 2005

according to the statistics at the beginning of 2001, the production capacity of the world's top ten polyethylene producers are: Dow Chemical Company 7.37 million tons/year, ExxonMobil company 6.11 million tons/year, equesta chemical company 3.19 million tons/year, Basel company 2.74 million tons/year, Chevron Phillips company 2.62 million tons/year, Saudi Basic Industry Corporation (SABIC) 2.43 million tons/year, Nordic chemical company (bore ALIS) 2.02 million tons/year, BP company 1.73 million tons/year, Nova chemical company 1.7 million tons/year, ATO fina company 1.6 million tons/year

the production of low density polyethylene (LDPE) by high pressure method is the most mature method in the production of PE resin. The kettle process and pipe process technology have been mature. At present, these two production processes coexist. Tubular production process is widely used in developed countries. In addition, foreign companies generally use low-temperature and high activity catalyst to initiate polymerization system, which can reduce the reaction temperature and pressure. LDPE Production by high pressure method will develop towards large-scale and tubular production. Titanium and chromium catalysts are mainly used in the production of high density polyethylene (HDPE) and linear low density polyethylene (LLDPE) by low pressure method. Ziegler titanium catalysts are mostly used in Europe and Japan, while chromium catalysts are mostly used in the United States

since the 1990s, the development of single active center (SSC) and metallocene catalyst technology has further promoted the technological progress of PE production process and PE products. According to statistics, metallocene and SSC catalysts produced and inspected whether the pressure spring of pressure stabilizing valve failed in 2000, and the PE produced reached 1million tons. Among them, 36% are for food packaging, 47% are for non food packaging, and 17% are for others (medicine, automobile and construction). Since the commercialization of metallocene polyethylene (MPE) in 1995, the global consumption of MPE resin has doubled every year. It is predicted that by 2005, the average annual growth rate of MPE demand will reach 25%, which is expected to reach more than 3 million tons. In 10 years, the PE capacity of 20 extrusion technology suppliers will reach 83million tons, of which 37% of LDPE and LLDPE and 20% of HDPE will use metallocene/ssc catalysts. MPE will reach 17million tons, including 7million tons of mLLDPE, 6million tons of mhdpe and 4million tons of mldpe

Ziegler Natta (Z-N) catalyst is also under development. BP and Nova Chemical Co., Ltd. jointly developed the advanced Z-N catalyst novacatt catalyst, which has been industrialized. Other high-performance PE catalysts have also been developed and introduced to the market. Samsung chemical company of South Korea launched a new industrialized PE catalyst, which can produce high-performance PE, especially c6-lldpe and MDPE, and its impact strength is comparable to that of metallocene products. The environmental stress cracking resistance of the prepared MDPE is 6 and 10 times that of metallocene and Z-N catalyst products, respectively. This catalyst, called hybridcg, is an organometallic compound of titanium or zirconium supported on manganese oxide products and activated with alumina cocatalyst. It combines chelating ligands and shares electrons with transition metals. The catalyst is suitable for gas-phase polymerization in fluidized bed reactor, and has been industrially verified on an 80000 T/a unit. Its production cost is only 25% of that of metallocene catalyst, and the 1-hexene comonomer required for the reaction can be reduced by 30%. Mitsui chemical company of Japan has also developed a new complex catalyst, whose activity can be more than 10 times that of metallocene catalyst. It is composed of group IV metals such as chromium, titanium or hafnium chelated with two phenoxyimine ligands. Aluminoxane is used as co catalyst, and its price is 1/10 of that of metallocene catalyst

after decades of development of PE resin in China, 23 sets of PE plants have been built, with a total production capacity of 2.358 million tons/year. It is estimated that the output of PE in 2005 will reach 4.92 million tons, and the output of LDPE, LLDPE and HDPE will be 1.28 million tons, 1.55 million tons and 2.09 million tons respectively. However, the output of PE in China can not meet the demand. It is estimated that the import of PE will increase from 3million tons/year now to 5million ~ 7million tons/year in 2005

there is still a big gap between China and foreign countries in the production and development of PE resin. In the future, we should further expand the production scale, improve product quality and add new varieties. At the same time, we should strengthen the research of catalysts, especially bifunctional, bimetallic and metallocene catalysts. In addition, we should continue to strengthen the research and development of slurry HDPE process, gas phase process and PE special resin and special material varieties

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