Low-pressure methanol synthesizing process

Abstract

The invention relates to a low-pressure methanol synthesizing process. In the low-pressure methanol synthesizing process, both a primary reactor and a secondary reactor adopt a boiler feed water forced circulating heat transfer technology, heat transfer is fast and efficient, the device layout can be effectively simplified, the project investment of a device frame is reduced, and the problems of circulating ratio decrease, a non-ideal heat effect and the like, which are caused by inaccurate calculation of the layout height of a steam pocket, do not appear; through forced circulation, the circulating ratio can be effectively increased, reaction heat can be efficiently and reasonably utilized, and the heat transfer effect is enhanced; a jumper wire is arranged between an outlet of a synthetic gas compressor and an inlet of the secondary reactor, so that stable operation of catalysts in the two stages of reactors in different stages of the service life is achieved, and through the jumper wire, loads of the reactors are conveniently and forcibly adjusted, so that the production ratio of medium-pressure steam to low-pressure steam is flexibly adjusted; a connection position of fresh synthetic gas is arranged behind a synthetic gas thermostat, so that the heat transfer area and the specification of the synthetic gas thermostat can be reduced and the project investment is reduced.

Description

technical field [0001] The invention relates to a low-pressure methanol synthesis process. Background technique [0002] Methanol is an important C1 chemical basic product and organic chemical raw material, and methanol synthesis is a reversible exothermic reaction with reduced volume. Since the German BASF company successfully developed the high-temperature and high-pressure gas-phase methanol synthesis process in 1923, the methanol synthesis process has experienced the technological development process of synthesis gas pressure from high pressure to low pressure, synthesis temperature from high temperature to low temperature, and reactor from adiabatic to isothermal. In recent years, with the progress of methanol synthesis technology and the continuous improvement of the country's energy consumption and environmental protection requirements, methanol synthesis technology is continuing to develop in the direction of large-scale, energy-saving, and environmental protection. ...

AI Technical Summary

Problems solved by technology

[0004] (1) Both the first methanol reactor and the second methanol reactor adopt natural circulation technology to remove the reaction heat. This technology has strict requirements on the layout of the steam drum connected to the reactor, and has low heat exchange efficiency and high investment, which is not conducive to the reaction problems such as device enlargement;

[0005] (2) There is no effective means of adjusting the reaction load between the first reactor and the second reactor, which will have two adverse consequences: one is when the catalysts in the first reactor and the second reactor are in different service life states , it is impossible to effectively adjust the load of the two-stage reactors in series; the second is that it is impossible to moderately adjust the gas production of the medium-pressure steam drum and the low-pressure steam drum;

[0006] (3) The access position of fresh syngas and recycle gas is not reasonable enough, because the pressure ratio of fresh syngas through the compressor is relatively large, and the temperature after compression is relatively high. At this time, it is mixed with low-temperature recycle gas, causing the temperature of the mixed gas to rise High, subsequent heat exchange will make the logarithmic average temperature difference smaller, thereby increasing the heat exchange area, heat exchanger specifications and engineering investment

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