Questions regarding the frozen compressor process
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The last edit to this post was made by 654262293 on 2010-10-14 at 10:00 :P I have a question for the experts: in the refrigeration process, screw compressors are used, with all compressors being of the same model. The ammonia gas comes from both the primary and secondary ammonia cooling systems. Is it feasible to send the ammonia gas discharged after compression through each compressor into a common pipeline before sending it to the evaporator? I heard from a senior that low-pressure gaseous ammonia has a higher compression ratio, which results in a very high temperature of the ammonia being discharged. It isn’t reasonable to feed such high-temperature ammonia directly into the evaporation cooler after compression; two stages of compression are necessary, otherwise the temperature is too high for condensation to occur! But another senior said that this approach is feasible; I’m very confused and unsure whether such a design is reasonable. I hope everyone can provide analysis and assistance! :P Thank you all!
Why isn’t anyone responding? Please, everyone!
:'(Who can help me?
It is inappropriate to use a screw chiller of the same model to handle ammonia gas with two different evaporation pressures. A feasible approach is to use a set of screw chillers for low-pressure ammonia cooling; the ammonia is compressed to the evaporation pressure required for high-pressure ammonia cooling, after which it merges with the ammonia coming from the high-pressure cooling system. Another type of screw chiller is then used to compress the ammonia to an even higher pressure, causing it to condense into liquid ammonia. This liquid ammonia is then sent to another cooling unit, and from there to yet another cooling unit, thus completing one cycle.
It should be feasible. Our process involves mixing primary and secondary ammonia-cooled ammonia together, feeding it into a screw chiller; there is one outlet pipe from the chiller, which then leads to the evaporation cooling units.
There should be no problem, as long as the screw compressor can handle it.
The key is to consider the cooling temperature and vapor ammonia evaporation pressure required for primary and secondary ammonia cooling; the inlet pressure of the screw compressor must meet the requirements of the cooling temperature and vapor ammonia evaporation pressure specified for secondary ammonia cooling.
Reply to 7# wangoolei: Do you mean that different models of compressors need to be chosen depending on the source of gaseous ammonia?
If this must be done, different models of chillers need to be selected for screw chillers. The premise of this solution is to select two screw chillers of different models, which should be the optimal approach. Reducing high-pressure gaseous ammonia to low pressure and then compressing it using an ice machine is unreasonable from the perspective of energy utilization, as it results in energy waste.
Reply to 9# sun0225: Should high-pressure gaseous ammonia be depressurized first before being compressed? It’s indeed a waste of energy. According to what you say, it would be better to first compress the low-pressure ammonia to the same pressure as that of the high-pressure ammonia, and then compress it together with the high-pressure ammonia before sending it to the evaporation cooler!
This post was last edited by Chemical Gas Purification on 2010-10-17 at 12:57. It’s necessary to check what the temperature at the compressor inlet is; there are no major issues with the outlet pressure and temperature