Light hydrocarbon separation method used in methanol to olefin device

Abstract

The invention relates to a light hydrocarbon separation method used in a methanol to olefin device. According to the method, through the optimization for conventional technological processes, the recovery rate of ethylene and propylene can be effectively improved, meanwhile, other absorbents are not introduced, and materials such as ethane, propane and three-carbon mixture in a system are used to absorb; multi-section absrptions, namely, main absorption and auxiliary absorption are arranged, a main absorption liquid is short in circulation in the system, and can effectively reduce the system operation load and reduce the device running cost, the auxiliary absorption circulating process is relatively longer than that of the main absorption, but the circulation amount is small, and the influence on the system load is relatively small. Through the adoption of multi-stage absorption, the separation of gases of methane, hydrogen, nitrogen, oxygen, carbon monoxide, ethane and the like from ethylene, propene and propane can be realized without copious cooling. The loss of ethylene and propene in fuel gas is small, the separating efficiency is high, and fuel gas products with less propane can be obtained, propylene and ethylene products satisfying polymer grade requirements can be manufactured, and, meanwhile, propane products with high purity can be obtained.

Description

technical field [0001] The invention belongs to the field of coal chemical industry, in particular to a method for separating light hydrocarbons in a methanol-to-olefins device. Background technique [0002] In recent years, my country's methanol-to-olefins projects have made considerable progress, and companies such as Shenhua and China Coal have launched large-scale methanol-to-olefins projects. For the methanol-to-olefins project, on the one hand, the reaction device and catalyst system play a decisive role in the selectivity and conversion rate of the reaction; on the other hand, the separation of the light hydrocarbon mixture produced by the reaction is also a key factor affecting the investment in the device and the cost of the product. [0003] For the olefin mixture produced in the methanol-to-olefin project, its components are similar to petroleum cracking gas and refinery dry gas. Therefore, typical separation methods include conventional cryogenic process and oil ...

AI Technical Summary

Problems solved by technology

[0013] The main purpose of the present invention is to overcome the problems of large equipment investment and high operating costs in the light hydrocarbon separation method in the methanol-to-olefins unit in the prior art, and provide a light hydrocarbon separation method in the methanol-to-olefins unit by optimizing the existing process flow. Separation method, which can effectively improve the recovery rate of ethylene and propylene

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