Inert gas content in methanol synthesis
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At the beginning of production operation, the catalyst has high activity, and the content of inert gases in the methanol synthesis cycle gas is kept between 20% and 30%； In the later stages of production operation, the catalyst activity decreases, and the content of inert gases in the recycle gas is generally kept between 15% and 25%. Could everyone discuss how, in practice, the amount of inert gas can be adjusted in a timely manner based on the catalyst’s activity?
Original poster, you’ve posted this question in the wrong place; it should be posted in the forum dedicated to methanol and its downstream products. The main economic indicator reflecting catalyst activity is the synthesis rate. If this rate decreases under the same cycle ratio and other parameters, it indicates that the catalyst’s activity has declined; in such cases, the inert gas content should be reduced appropriately, which can be achieved by venting some of the gas or increasing the hydrogen recovery capacity.
At the beginning of catalyst use, at the designed temperature, the product content at the outlet of the synthesis tower can meet the design requirements； During subsequent use, under the same operating conditions, the content of the product at the outlet of the synthesis tower will gradually decrease. In practical operations, it is necessary to: 1. Increase the reaction temperature ； 2. Reduce the volume of circulating gas and increase the volume of vent gas; if all hydrogen is recovered and sent back to the compressor outlet, the conversion load also needs to be adjusted ；
If thermal equilibrium can be maintained, the circulation rate should be increased as much as possible. If the catalytic performance is good, the pressure in the synthesis system is low; if the performance declines, the pressure rises, which can be easily observed. Additionally, it can be determined by measuring the decrease in the temperature at the hot spots in the bed layer or by calculating the equilibrium temperature difference.
The required level of system inert gas varies at different stages of catalyst use.