Methanol Weekly Topic What causes the temperature in the methanol synthesis tower to drop? 2016.02.14---02.21

Introducing liquid methanol into the tower causes a rapid drop in the temperature of the catalyst layer. (1) Changes in the gas composition cause the temperature of the catalyst layer in the synthesis tower to drop. If the hydrogen-to-carbon ratio of the fresh gas is inappropriate or if the methane content increases, it will affect the methanol synthesis reaction; this reduces the heat generated by the reaction, causing the temperature of the catalyst layer in the synthesis tower to drop. (2) A sudden decrease in the amount of fresh gas can also cause a drop in the temperature of the catalyst layer in the synthesis tower. A decrease in gas volume may also be caused by a compressor tripping or leaks in the equipment or pipelines. (3) Damage to the internal components of the synthesis tower. (4) The illusion of a temperature drop caused by instrument failure.

A sudden drop in the temperature of the catalyst layer in the synthesis tower can be caused by several factors: (1) The introduction of liquid methanol into the tower can lead to a rapid decrease in the temperature of the catalyst layer. The main reason is the loss of control over the liquid level in the crude methanol separator; the excessive liquid level caused liquid methanol to be carried out through the gas outlet, pass through the circulator, and then enter the synthesis tower. Solution: Open the separator drain valve to establish a normal liquid level, and reduce the circulation rate to maintain a normal tower temperature. (2) Excessive circulation volume lowers the bed temperature; reduce the circulation volume. (3) Changes in the gas composition can also cause a decrease in the temperature of the catalyst layer in the synthesis tower; for example, an increase in the CH4 content in the feed gas, or an improper ratio of (H2-CO2/CO+CO2), can affect the methanol synthesis reaction, reducing the heat generated by the reaction and thereby lowering the temperature of the catalyst layer in the synthesis tower. Solution: Please ask the gas production team to adjust the gas composition ； The flow rates of fresh gas and recycled gas are adjusted simultaneously to control the tower temperature. (4) If the drum pressure is low, lower the bed temperature to increase the drum pressure. (5) A sudden decrease in the amount of fresh gas can also cause a drop in the temperature of the catalyst layer in the synthesis tower. A decrease in the amount of fresh air may be caused by a compressor trip or by leaks in the equipment or pipelines. Handling method: Maintain the normal tower temperature and promptly arrange maintenance. (6) Damage to the internal components of the synthesis tower causes the gas to take a short circuit within the tower; the gas enters the catalyst layer directly without passing through the heat exchanger, resulting in a drop in tower temperature. The internal components of the synthesis tower have a complex structure; therefore, it is necessary to be cautious and thorough when determining whether there are defects in these components, and no hasty conclusions should be drawn. (7) Temperature drop caused by instrument failure. At this time, the operator should analyze and determine from various aspects whether the instrument is functioning properly, and ask an instrument technician to inspect and repair it.