Refrigeration method for methanol synthesis and separation

Abstract

The invention discloses a refrigeration method for methanol synthesis and separation, and belongs to the technical field of a methanol production process. According to technical essentials of the method, a synthesized gas after a methanol synthetic reaction is subjected to cooling through a heat exchanger and enters an air condenser for further cooling to obtain liquid crude methanol, wax generated in a liquid side reaction, and an un-condensed synthesized gas; a methanol separator is installed after the air condenser to enable wax, generated in the liquid side reaction, together with liquid crude methanol enters the methanol separator and following treatment equipment, so that a total amount of wax entering a following water condenser is reduced, and a wax precipitation speed of the water condenser is reduced; and the un-condensed synthesized gas is subjected to cooling through the heat exchanger and separation through a methanol separating column to enable methanol to be fully condensed and separated, so that the content of methanol in the synthesized gas cycled to a synthetic tower is reduced, and the methanol synthetic reaction in the synthetic tower is promoted to move towards a positive reaction direction. According to the method, the yield of methanol is increased; the service cycle of the device is prolonged; and energy consumption is reduced.

Description

technical field [0001] The invention relates to a methanol synthesis and separation refrigeration method, which belongs to the technical field of methanol production technology. Background technique [0002] Methanol is an important organic chemical raw material and high-quality fuel. Industrially, coal, naphtha, refinery dry gas and natural gas are mainly used as raw materials to produce methanol. [0003] The methanol synthesis reaction is a high energy-consuming process with a low conversion rate, and the effective yield of methanol per pass is only 5% to 9%, so the effective recovery of methanol is very important. The partial pressure of the methanol gas phase in the synthesis gas decreases with the decrease of the temperature. Therefore, the cooling of the outlet gas of the methanol synthesis tower is an important link in the methanol production process. The partial pressure of the methanol gas in the gas will cause the gaseous methanol in it to not be condensed compl...

AI Technical Summary

Problems solved by technology

These alkanes form wax after being condensed by the water condenser, and these waxes are finally adsorbed on the surface of the water condenser, seriously affecting the condensation effect of the methanol unit

As the temperature increases, the separation effect of methanol becomes worse, and the methanol production drops sharply

At the same time, the synthesis cycle gas containing a large amount of gaseous methanol is sent to the synthesis reactor through the compressor for methanol synthesis reaction. As the reaction partial pressure of methanol increases, the synthesis efficiency of methanol further decreases.

When the synthesis gas containing methanol gas is sent into the compressor, it will cause a series of problems such as scaling of the compressor, greatly reducing the service life of the synthesis catalyst, decreasing methanol production, and poor synthesis efficiency.

[0004] The traditional method to reduce the methanol content in the cycle gas is to use high-efficiency separation equipment to separate the condensed liquid methanol in the cycle gas as much as possible, but this method can only separate methanol at saturation temperature and pressure. There is still a large amount of methanol that has not been condensed and separated, and the cycle gas flows repeatedly in the synthesis system, resulting in an increase in energy consumption

[0005] Therefore, the current technical problem is that in the methanol production system, the output of methanol synthesis is low and the maintenance cycle of equipment is short

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