Process flow for carrying out high-pressure and low-pressure adsorption treatments on polyolefin tail gas

Abstract

The invention provides a pressure swing adsorption process flow of high-pressure and low-pressure adsorptions, which is used for processing high-pressure polyolefin tail gas and low-pressure polyolefin tail gas generated in the production process of polyolefin and polypropylene to obtain high-concentration hydrocarbon-enriched gas and purified nitrogen gas. The process flow comprises at least four adsorption beds; each adsorption bed is sequentially used for the steps of low-pressure adsorption, high-pressure adsorption, concurrent discharge 1, concentration, vacuumization, vacuum washing, pressurization and the like; the low pressure polyolefin tail gas does not need to be treated by special compression and pressurization so that the cost for investing and operating a device is saved; meanwhile, the operation reliability of a tail gas recycling device is improved.

Description

technical field [0001] The invention relates to a process for treating vented tail gas produced in the production process of polyolefins, especially a process for separating high and low pressure tail gases produced in the production process of polyolefins such as polypropylene and polyethylene, recovering hydrocarbon components and purifying nitrogen process. Background technique [0002] In the production process of polyolefins such as polyethylene and polypropylene, olefin monomers such as ethylene and propylene undergo polymerization reactions to produce solid polyolefin powder. Products of different purposes and polyolefin plants with different production processes will also produce various tail gases during the production process, such as the exhaust gas from the polymerization tank, the exhaust gas from the degassing chamber, the exhaust gas from the dryer, the sealing gas, equipment and Valve leaks gas, etc. Some polyolefin production plants have both polyethylene ...

AI Technical Summary

Problems solved by technology

This process method mainly recovers the high-pressure tail gas after membrane separation, and does not recycle the low-pressure tail gas produced by the polyethylene plant, nor does it include the recovery and treatment of polypropylene tail gas

In addition, the hydrocarbon-rich gas recovered by pressure swing adsorption has relatively low hydrocarbon concentration and can only be used as fuel gas, which greatly reduces the recovery benefit

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