Problem of no liquid delivery in the reabsorption pump of the carbon dioxide absorption tower in Luchi’s low-temperature methanol washing unit’s second tower
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Our unit features a low-temperature methanol washing process designed by Saiding (formerly the Second Chemical Research Institute), using a nine-tower configuration. However, in actual operation, under high load conditions (94%), the reabsorption pump in the carbon dioxide absorption tower tends to fail to draw in liquid – the exhaust gas from the pump cannot be completely removed – which results in an increase in carbon dioxide levels. The situation improves as soon as the load is reduced, but this prevents the low-temperature methanol washing system from operating at higher loads. Experts, please analyze what is causing this issue.
Help me out, someone please! ! ! ! ! ! !
That is cavitation in the pump, and our company also faces this issue. The pump can be modified by adding an inducer wheel.
Is it due to the pump? Why does this situation occur only under high load?
This post was last edited by zwp997 on 2015-8-19 21:52. Under high flow rates, the required cavitation margin of the pump increases, so cavitation may have occurred. Hydraulics did not calculate this pump properly. It seems impossible to fix it; the only option is to replace the pump, or else reduce production volume, but the latter isn’t a viable solution.
I’m not sure if it will work by increasing pressure or lowering temperature
Increasing pressure doesn’t work; reducing temperature has an effect, but it’s not possible to lower it any further.
There is gas, but it can never be completely released. It’s to see if the problem can be resolved without replacing the pump.
Add a flash tank to the pipeline ahead of the pump, and activate it when the load is high......
It’s a good idea, but my company produces urea, so this wastes carbon dioxide
As you mentioned, there is an issue with the pump selection; at low loads, the temperature of the CO2-rich methanol liquid is relatively low, so cavitation does not occur. Cavitation appears only at higher loads. To resolve this completely, the pump either needs to be replaced or modified. Operation can only be maintained by methods such as reducing the load, lowering the methanol temperature, increasing the system pressure, and raising the inlet liquid level of the pump.