Method for controlling CO/H2 molar ratio in coal to methanol purification device

Abstract

The invention relates to a method for controlling the CO / H2 molar ratio in a coal to methanol purification device. The method is characterized by comprising the following steps: (1) feeding rough synthesis gas from a gasification unit into a gas-liquid separator, performing gas-liquid separation, and dividing the separated gas phase into two paths, namely a first path of synthesis gas and a second path of synthesis gas, wherein the flow ratio of the first path of synthesis gas to the second path of synthesis gas is 1:(0.58-0.85); (2) performing heat exchange on the first path of synthesis gas, and performing CO conversion in a CO conversion unit to obtain converted gas; (3) performing heat exchange on the converted gas until the temperature of the converted gas is less than or equal to 50 DEG C, separating out a liquid phase, performing low-temperature rectisol in a first absorption tower to obtain a first path of purified gas, performing heat exchange on the second path of synthesis gas until the temperature of the second path of synthesis gas is less than or equal to 50 DEG C, separating out a liquid phase, and performing low-temperature rectisol in a second absorption tower to obtain a second path of purified gas; and (4) merging the first path of purified gas and the second path of purified gas to obtain methanol synthesis gas. By utilizing the method, a perfect CO / H2 mole ratio can be obtained, the energy consumption of the device is low, and the purpose of reinforcing the operability of the device can be achieved.

Description

technical field [0001] The invention relates to a coal-to-methanol process, specifically referring to a process for controlling CO / H in a coal-to-methanol purification device. 2 molar ratio method. Background technique [0002] In recent years, my country has adopted coal water slurry, dry pulverized coal, and crushed coal gasification technology to produce methanol, etc., because the crude synthesis gas directly produced by the gasification device contains CO, H 2 In addition to the effective gas, it also contains H 2 S, CO 2 , NH 3 In order to meet the raw material gas requirements of downstream methanol synthesis and butyl-octanol units, it is necessary to control and adjust the H in the synthesis gas 2 / CO, and removal of H 2 S, CO 2 , NH 3 Wait for acid gas. [0003] At present, coal-to-methanol units generally adopt the process of gasification→carbon monoxide shift→low temperature methanol elution to remove acid gas→methanol synthesis. The raw syngas from the ...

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Problems solved by technology

Such a process setting leads to a large size of the absorption tower in a large coal chemical plant. At the same time, one feed means only one absorption system is set up, which cannot optimize the methanol circulation system of the low-temperature methanol washing absorption part, and the cooling capacity consumption is high.

[0006] Nowadays, with the large-scale production scale, the disadvantages of this process become more and more obvious.

At the same time, due to the limitations of equipment manufacturing technology and transportation conditions, it is difficult for a single series of equipment to handle more than 1 million tons of methanol

At the same time, the carbon monoxide shift unit and shift furnace catalyst in the large-scale coal-to-methanol plant are loaded more, and it is more difficult to control the temperature of the catalyst bed, the activity of the reaction, and the degree of CO shift reaction.

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