What is the flow rate of acidic gas at the top of the unit’s regeneration tower?
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I have set the flow rate of acidic gas at the top of the regeneration tower; the normal value is 95 nm3/h. Currently, it is only 6295 nm3/h, because the flow rate of the lean liquid is only 15 t/h, and it’s not possible to increase this flow rate. It’s not a problem with the lean liquid pump; the flow rate of the lean liquid can be increased, but the flow rate of the rich liquid cannot be increased. As a result, the liquid level in the absorption tower rises while the liquid level in the regeneration tower drops. The filter screen at the inlet of the rich liquid pump has also been cleaned many times; after cleaning, the flow rate increases and can reach 25 t/t, but it starts to drop again after a few days. I think the amine scavenger should be cleaned once; that might help. During sampling, it was found that the rich liquid was very dirty. The absorption tower does not perform well due to the low flow rate of the lean liquid. The flow rate of the lean liquid can reach 30 t/t, and the acidic gas volume in the regeneration tower can exceed 100 nm3/h. I would like to know what the flow rate of the lean liquid in your unit is, and what the acidity level of the gas at the top of the regeneration tower is
The liquid flow rate and acid gas volume you mentioned are not comparable; it’s better to compare them with the design capacity of your facility. Based on what you’ve described, I believe it’s due to a clogged rich liquid filter. Therefore, try bypassing the filter first.
Not long ago, the flow rate of the lean liquid was only 10 t/h; after cleaning the filter at the inlet of the rich liquid pump, the flow rate of the lean liquid increased to 25 t/h. It could be clearly seen on the DCS that the volume of acidic gas at the top of the regeneration tower rose from 47 nm3/h to 95 nm3/h. This kind of data change has occurred many times. Of course, this is also related to the concentration of ethanolamine in the lean liquid and the H2S content in the exhaust gases. Because the lean liquid filters tend to clog, the workshop has backup lines for all the filters in the quench tower and regeneration tower.