Process flow for separating low-carbon hydrocarbons and separating gas during production of olefins (M-OS/MTO) from methanol

Abstract

The invention provides a non-cryogenic oil absorption separation method for a mixture of low-carbon hydrocarbons, which is used for separating the mixture of the hydrocarbons from gas during production of olefins from methanol. Methane / hydrogen can be separated from heavy components, namely C2 and above by absorbing fractions of the C2 and above by adopting two or more strands of absorbing agents. According to the method disclosed by the invention, an absorbing agent separating tower is increased before a demethanization tower, one strand of material flow, which is separated from the tower is taken as a main absorbing agent of the demethanization tower for absorbing the C2 and C3, the strand of the absorbing agent is the mixture of the fractions, which is from the former system and needs to be separated, and circulation is not required. The second strand of the absorbing agent of the demethanization tower is from a system including a depropanization tower and a debutanization tower, and the absorption effect is further enhanced. Compared with the prior art, the method can greatly reduce the using quantity of the circulating absorbing agents; moreover, the multiple strands of the absorbing agents are adopted, equipment investment and energy consumption are significantly reduced, the recovery rate of ethylene and propylene is further improved; and furthermore, the flow is simple, the operation cost is low, and the operation is safe and reliable.

Description

technical field [0001] This low-carbon hydrocarbon separation and methanol-to-olefins (M-OS / MTO) gas separation process is suitable for oxidation to olefins, hydrocarbon cracking, hydrocarbon catalytic reaction to produce olefins, and is also suitable for traditional petrochemical ethylene fields. Background technique [0002] Most of the intermediate and final products in the petrochemical industry are based on olefins and aromatics. The ethylene unit is the main production unit for the production of olefins (ethylene, propylene, butadiene) and aromatics. In the past, olefins were mainly produced by thermal cracking of naphtha through a tube furnace. In recent years, due to the shortage of petroleum resources, the methanol-to-olefins (MTO / MTP) technology has been gradually developed and entered the stage of industrialization. Methanol-to-olefins technology consists of reaction technology and separation technology. Reaction technology is centered on the development and des...

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Problems solved by technology

[0010] The currently industrialized Shenhua Baotou MTO plant uses propane-based absorbents to enter the top plate of the demethanizer to absorb components of C2 and above. The absorption efficiency is good, but the amount of absorbent is large and the absorption The agent comes from the follow-up separation system (propylene rectification tower still), and the circulation route is long, resulting in relatively large equipment such as towers, high investment and high energy consumption

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