Polyethylene
| 원료 | Ethylene and comonomers | ||
| 생산물 | polyethylene | ||
| 적용 | To produce linear low-density polyethylene (LLDPE) to high-density polyethylene (HDPE) using the lowpressure, gas phase Unipol process. | ||
| 설명 | Description: A wide range of polyethylenes is made in a gas phase, fluidized bed reactor using proprietary solid catalysts. The product is in a dry, free-flowing granular form substantially free of fines. Melt index and molecular weight distribution are controlled by selecting the proper catalyst type and adjusting operating conditions. Polymer density is controlled by adjusting comonomer content of the product. High catalyst productivity eliminates the need for catalyst removal. The simple and direct nature of this process results in low levels of environmental pollution, minimizes potential fire and explosion hazards, and makes the process easy to operate and maintain. Gaseous ethylene, comonomer and catalyst are fed to a reactor (1) containing a fluidized bed of growing polymer particles and operating near 20 kg/cm2 and approximately 100℃. A conventional, single-stage, centrifugal compressor (2) circulates reaction gas which fluidizes the reaction bed, provides raw material for the polymerization reaction, and removes the heat of reaction from the bed. The circulating gas is cooled in a conventional heat exchanger (3). The granular product flows intermittently into product discharge tanks (4) where unreacted gas is separated from the product. The vent gas is compressed and returned to the reactor. Hydrocarbons remaining with the product are removed by purging with nitrogen. The granular product is subsequently pelletized in a proprietary low-energy system. Products: Polymer density is easily controlled from 0.915 to 0.97 g/cm. Depending on catalyst type, molecular weight distribution is either narrow or moderately wide. Melt index may be varied from less than 0.1 to greater than 200.
Raw materials and utilitles consumption: Per metric ton of pelleted polymer:
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