Questions about the selection of low-temperature ethylene pumps
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This post was last edited by FLYTOINTER on 2010-7-14 12:27. I have a new project here, which involves low-temperature ethylene that needs to be sent from the low-temperature tank to the device reactor. Now I am encountering some difficulties or conflicts in the selection of the pump. I would like to ask for your help, and I would like to express my thanks in advance. My output process is as follows: low-temperature ethylene tank (0.6MPA) --- pump (pressurized to 2.2MPA) --- vaporizer (normal temperature) --- reactor (2.1MPA). The specific required conditions are as follows: Q=950~1000KG/H (-69℃), P in the raw ethylene tank is: 0.6MPA (G); the required outlet pressure reaches: 2.2MPA (G). Based on the above conditions, my selection plan is as follows: 1) Choose a multi-stage pump, (but the efficiency is too low, and the manufacturer said that it is a horizontal multi-stage pump, which is difficult to choose with such a small flow rate (about 2.0NM3/H based on the temperature conversion); and the on-site location is not convenient for layout (there is a problem of cavitation margin). The manufacturer suggested that I choose their barrel pump, but after considering the cavitation margin, it has to be arranged underground. So I don’t want to choose this. 2) When choosing a reciprocating pump, consider using the vaporizer outlet pressure as a signal. Add a frequency converter to the reciprocating pump, use the vaporizer outlet pressure signal to adjust the speed of the variable frequency, and rely on the speed of the pump to adjust the flow rate. (This type of pump also solves the problem of cavitation.) I hope you can have an extensive discussion (from the perspective of safety, reliability and economy) on whether the second selection option above is advisable and whether it is appropriate. Thank you very much!
Which "manufacturer" did you mention? Is it Hermetik?
It is recommended to choose a barrel pump, as safety and reliability are guaranteed. After all, the stability of the device is the first priority, followed by economics. For reciprocating pumps, future maintenance costs may be relatively high, and reliability may not be guaranteed.
Choose vertical multi-stage canned pump, this is how we use it
It is recommended to use Hermetic canned pumps. We have been to Shanghai Petrochemical's liquefied gas project, which uses a large number of Hermetic canned pumps. The cavitation margin of the canned pump is low. If you have special requirements, you can also install a pump inlet guide impeller to further reduce the cavitation margin of the pump. Some usage conditions are similar to yours and the usage conditions are good. If Dalian Hermetic cannot provide it, it can be provided by the German headquarters company. It is recommended to contact the Dalian company to help with selection. I also think that a barrel pump is possible, but it is more troublesome, so it is better to use a canister pump.
What are the differences between bucket bag pumps and canned pumps? Can you introduce it, the concept is rather vague!
I would like to inform you of my final selection plan here. I finally selected the Haimi multi-stage canned pump. Thank you for your suggestions. I also hope that you can give feedback on the results when you ask questions in the future.