Why is the methanol content in the exhaust gas leaving the exhaust gas scrubber high after maintenance and startup?
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What measures should be taken subsequently to control it?
Low recycling efficiency or equipment issues
Low-temperature methanol washing, from Dalian University of Technology
Possible factors include excessive nitrogen stripping volume and insufficient washing water volume in the wash tower
I think it’s due to an excessive gas-liquid ratio in the exhaust gas scrubber, as well as a high temperature of the scrubbing liquid! 1. It can reduce the amount of nitrogen used for air lifting and thus decrease the volume of exhaust gases (but this is not favorable for methanol regeneration) ； 2. Increase the amount of desalinated water used in the exhaust gas scrubber (but this increases the load on the methanol water distillation tower) ； 3. Find a way to lower the temperature of the demineralized water used for washing!
There are several possibilities: 1. The temperature of the deionized water is high； 2. Low consumption of demineralized water ； 3. High methanol content in exhaust gases ； 4. Problems with the tray cause insufficient contact, resulting in poor absorption efficiency.
Was anything touched during the maintenance of the tower internals? Furthermore, the liquid level or pressure at the upper part of the reabsorption tower is too high
The poster has provided too little information. Which equipment was repaired? Is there any maintenance work on the exhaust gas scrubber? Is the high methanol content in the exhaust present after every maintenance session, or is it only this time? Have there been any changes in the material parameters of the exhaust gas scrubber? It’s difficult to analyze without a detailed description of the operating conditions.
The amount of exhaust gas does not match the amount of water used for washing, or there is a fault with the internal components of the tower