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zhouweidl
06-11-2006, 07:25 AM
:confused: If we use propylene as frigerant in the screw compressor,is there any criteria of the propylene refrigerant?If some chemical plant can provide propylene which purity is up to 98%,can I use the propylene as refrigerant?

NoNickName
06-11-2006, 12:29 PM
I would recommend to buy specifically R1290 (propylene refrigerant grade 99.8%)

TXiceman
11-11-2006, 03:15 AM
If you use a 98% purity R1270, you need to know what the other 2% is made of. If it is light ends, they will tend to concentrate in the condensing system and raise the partial pressure. They will tend to act as inerts and increase the condensing pressure and increase power consumption. These can be bleed off and get you back closer to pure R1270 properties.

You can also have heavy ends which will collect in the evapoarator and change the bubble point of the refrigerant and change the evaporator temperature/pressure relation and capacity of the compressor.

Given the gas composition a compressor vendor can run the simulation and give you the actual performance of the compressor and gas composition.

Next problem is water in the refrigerant. If you are operating below the freeze point of water, you can get the water freezing in the expansion device. Also, in a screw compressor, the oil will pick up any free water and the filter being paper fiber elements, will swell and give the an apparent plugged filter. You might be changing a lot of filters to get the water under control. You can use a fiberglass oil filter element which will pass the water. Enough water in the oil can acause some oil problems as well.

We use screw compressors on some wet gas applications and have to make sure we have adequate oil filtration as well as frequent oil changes and the proper oil.

You can use Sporland filter driers to help pull the water out of a R1270 system.

Ken

Ambrish_bajpai
30-07-2009, 01:01 PM
98% Purity is quite good and most of the times the other consitutents will be either propane , ehtylene or butane. Other consitutent does effect the properties and compressor selections as well. One of the important point is oil selection in such cases and we should inforem the oil vendor about the mixture and consitituents.We ahave used Sporlan in of the propylene projects but results were not that encouraging. I think that one should opt for those suppliers who are more familiar with refinery industry