However Ill give some general information. The effect of a given compression ratio is many things, your question is light on specifics.
Compression ratio is: As compression ratio increases the capacity decreases as less gas is drawn into the compression chamber and compressed. Compression ratio is the ratio of volume occupied when the piston is at the bottom of its stroke to the volume when the piston is at the top of the stroke. Process people say if we start at 50% capacity, the compressor will not trip as compression ratio should be lower than 1.86.I do not disagree since I believe compressors deliver flow and not pressure (so compression ratio will vary with flow), but I have read some of my old university courses and found that compressors deliver constant compression ratio.That is my concern.Įdited by sheiko, 06 December 2016 - 10:31 AM. The most important Compressor parameters are Threshold and Ratio. The volume of gas compressed by this P-V diagram is the difference in volume between Positions 1 and 4: This volume is influenced by the compression ratio (R C) and the magnitude of V 3. As a result if compression ratio remains at 1.86, then discharge pressure will be higher than PSHH and compressor will trip (if PSHH not desactivated). Problem is that during startup the compressor suction pressure will be 20.8 barg (then decreased to 14.8). PSV set pressure = 33.2 barg (while design pressure is 37.7 barg.and by the way designed with relieving flow rate twice bigger than 4775 Nm3/h because at the beginning of the project there were 2 cylinders.no comment) I personally would not go higher than that, and usually stick to 2:1 or lower on a mix buss. Many buss compressors will feature ratios even lower than 2:1 1.5 is common though some engineers prefer ratios as high as 4:1. discharge operating pressure : 28.5 barg (compression ratio = 1.86) For that reason, it’s common to use a lower ratio for buss compression. Well my concern is that we have revamped an existing compressor with the following process data (I just changed job two weeks ago, now in operations after 5 years doing process economics, so I was not involved in the study).