What impacts does the interruption of ammonia washing water in the scrubber have on the shift and low methane systems?
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What impacts does the interruption of ammonia washing water in the scrubber have on the shift and low methane systems? How should it be handled?
1. The liquid level valve at the bottom of the ammonia washing tower should be adjusted to a lower setting； 2. The pressure difference inside the tower will decrease, the space velocity will increase, and the separation efficiency of the ammonia-washing condensate water will be poor; as a result, some water vapor may be carried into the methanol washing process ； 3. The water and ammonia brought in for methanol washing will increase ； 4. The pressure of the process gas entering the methanol scrubber will increase.
What was said above is very good. I would like to add a few points: 1. The excessive ammonia content in the methanol wash leads to poor absorption efficiency, and ammonium carbonate crystals may form in the pipes, causing blockages； 2. The liquid level in the ammonia washing tower will experience temporary fluctuations.
1. The lack of spray cooling with ammonia wash leads to a significant increase in the temperature of the shift gas, which in turn increases the amount of ammonia present in the low-temperature methanol wash solution. 2. An increased amount of ammonia entering the low-temperature methanol wash results in an easy excess of ammonia concentration in the solution； Both of the above factors can easily affect the absorption efficiency and increase the degree of corrosion in the system; therefore, it is necessary to frequently analyze the ammonia and water content in methanol, and to control these levels promptly while preparing for gas switching. The other opinions are the same as those mentioned above!
The post by the original poster seems incorrect. 1. The lack of spray cooling with ammonia wash water causes the temperature of the shift gas to rise significantly, resulting in an increased amount of low-temperature methanol wash water being introduced. Since the temperature of the shift gas entering the wash tower is around 40°C, and the temperature of that wash water is also around 40°C, the interruption of the wash water supply has no effect on the temperature of the process gas. That is, the temperature of the transformed gas does not rise.
It is necessary to use an ammonia discharge valve to discharge ammonia into the acid gas system in order to reduce the ammonia content in the circulating methanol system and restore the ammonia washing water as soon as possible.
Where is your ammonia discharge valve located? Thank you!
An increased ammonia content in methanol can also lead to excessive sulfur levels in the purified process gas. Additionally, it increases the load on the methanol-water separation tower, making it easier for sulfur and ammonia to cause pipe blockages