System and method of preparing propylene tail oil by value-added exploitation of methanol

Abstract

The invention provides a system and a method of preparing propylene tail oil by value-added exploitation of methanol. The comprises a first reactor, a second reactor, a product separation unit, a c 4 hydrocarbon extraction, rectification and separation device and a heating furnace, wherein the first reactor performs dimethyl ether preparation reaction with methanol to form a first product flow; the second reactor synthesizes propylene by using a material from the heating furnace as a raw material to form a second product flow; the product separation unit receives and separates the second product flow to form propylene, c 4 hydrocarbon, a c 5 / c 6 hydrocarbon mixture and ethylene; the c 4 hydrocarbon extraction, rectification and separation device separates at least part of c 4 hydrocarbon to form a butylene product flow; and the heating furnace receives and heats at least part of first product flow, at least part of butylene product flow, at least part of c 5 / c 6 hydrocarbon mixture and at least part of ethylene. The system and the method can reprocess butylene alone, and supplement the removed butane part with the c 5 / c 6 hydrocarbon mixture; the reprocessing quantity of the tail oil is increased; the yield of propylene is increased; the value-added exploitation of the tail oil is achieved; and economic benefits are raised.

Description

technical field [0001] The invention belongs to the field of methanol-to-propylene technology, in particular to a system and method for value-added utilization of methanol-to-propylene tail oil. Background technique [0002] Propylene is one of the important basic chemical raw materials in the chemical industry. Methanol to propylene process, that is, using coal or natural gas as a raw material through synthesis gas, methanol, and then to propylene, as a non-petroleum route technology, gets rid of the shackles of oil shortage, and opens up a new raw material route for the production of propylene . [0003] The methanol-to-propylene technology of Shenhua Ningxia Coal Industry Group, located in Ningdong, Ningxia, is provided by Germany's Lurgi. For this device, the feed amount of the raw material dimethyl ether / methanol and the recycling amount of ethylene, C4 hydrocarbons, and C5 / C6 mixed hydrocarbons (C5 / C6 mixed hydrocarbons are part of the tail oil) Limited by the maxim...

AI Technical Summary

Problems solved by technology

In these existing technologies, after the extraction and separation of C4 hydrocarbons, only the separated butene is re-smelted, and the butane, which is not effective in producing propylene, is sent out of the boundary area as liquefied gas, thereby reducing the recovery of C4 hydrocarbons. Refining

It does not mention the impact on the refining amount of C5 / C6 mixed hydrocarbons, that is, it does not increase the utilization of tail oil, and cannot make full use of the by-products in the methanol-to-propylene process to increase the production of propylene

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