What are the reasons for overpressure in the methanol synthesis system? How should it be handled?
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What are the reasons for overpressure in the methanol synthesis system? How should it be handled?
The reasons for overpressure include an imbalance in the H/N ratio, accumulation of CH4 or N2, etc. The solutions are to increase the flow rate for hydrogen removal and recovery or to vent it and burn it off.
Changes in gas composition! As the amount of inert gases in the gas increases, the outward flow of gas should be increased while reducing the circulation volume. It is also possible that introducing methanol into the tower exacerbates the reaction, causing gas to accumulate inside the tower and leading to pressure buildup. There’s also catalyst deactivation, but this is usually easy to detect!
The content of inert gases in the gas increases, and these inert gases are not removed in a timely manner； There is an issue with the hydrogen-to-carbon ratio of the syngas ； Methanol enters the synthesis tower, deteriorating the reaction conditions inside and reducing the rate of reactions ； If the temperature of the tower synthesis gas is low, the synthesis reaction decreases ； The aging or deactivation of the catalyst leads to a reduction in reactions.
When the gas flow rate suddenly increases or the catalyst activity is significantly impaired, the system pressure rises, potentially reaching overpressure; abnormal operating conditions can also lead to overpressure. The system pressure can be appropriately adjusted by adjusting the air volume of the compressor and the amount of gas removed from the tower
In addition to what was answered by Shanghai You, I would like to add that the methanol separation is not effective, resulting in a high alcohol content in the recycle gas；
The reasons for overpressure in the methanol synthesis system include: 1. An increase in the amount of inert gases entering the synthesis system, with such inert gases accumulating and not being removed in a timely manner； 2. Changes in the process conditions of the synthesis system, such as changes in gas composition or process parameters; since methanol synthesis is a reaction that results in a decrease in volume, a deterioration in the methanol synthesis reaction occurs along with an increase in pressure ； 3. The air injection volume of the circulation machine decreases, the methanol production decreases, and the system pressure rises.