Olefin polymer effluent gas recycling device and method in production

Abstract

The invention discloses an olefin polymer effluent gas recycling device and method in production. The device comprises a compressing mechanism, a pre-dissociation mechanism and a cryogenic mechanism. The compressing mechanism is used for receiving effluent gas of olefin polymer in the production, the pressure of gas components in the effluent gas is compressed in the same grade, and recycled C4+ high-carbon hydrocarbon flow and residue effluent air flow are output. The pre-dissociation mechanism is used for receiving the residue effluent air flow from the compressing mechanism, and outputting recycled oligomerization physical flow and the residue effluent air flow. The cryogenic mechanism is used for receiving the residue effluent air flow from the pre-dissociation mechanism, and recycling C2+low carbon hydrocarbon flow and nitrogen flow in the residue effluent air flow. By cooperative working of the compressing mechanism, the pre-dissociation mechanism and the cryogenic mechanism, hydrocarbon substances in the effluent gas can be effectively recycled, it is achieved that the low polymer is recycled in low energy consumption, and meanwhile the hydrocarbon and the nitrogen with high recycling rates can be obtained.

Description

technical field [0001] The invention belongs to the field of tail gas treatment, and in particular relates to a device and method for recovering exhaust gas in the production of olefin polymers. Background technique [0002] During the production of olefin polymers, unreacted hydrocarbons (ethylene, ethane, propylene, butene, butane, isopentane, hexene, etc.), nitrogen, Hydrogen, residual catalyst, etc. These unreacted hydrocarbons and hydrogen must be removed, and the residual catalyst in the polyolefin resin must be deactivated to meet environmental protection standards and ensure the safety of downstream processes and products. Therefore, polyolefin resin needs to be devolatilized to obtain qualified products. The exhaust gas produced by the devolatilization process contains a large amount of hydrocarbon components. If it is directly discharged to the flare system for combustion without recovery, it will cause serious waste of raw materials and economic losses. At the s...

AI Technical Summary

Problems solved by technology

The compression condensation method mainly has the following disadvantages: the lower the content of condensable hydrocarbons in the exhaust gas, the lower the efficiency of the compression condensation method; The recovery rate is generally not more than 30%; the concentration of nitrogen in the uncondensed tail gas cannot meet the requirements of devolatilization, and it cannot be recycled and can only be discharged to the flare system

[0007] Although the above method can realize the recycling of hydrocarbons and nitrogen, it cannot remove the oligomers that may exist in the exhaust gas. If the oligomers cannot be separated, the recovery rate of hydrocarbons and nitrogen will decrease, the equipment pipeline will be blocked, and the operation will be affected. Stability, increased energy consumption for separation, and potential safety hazards

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