Reciprocating compressor
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Why is the suction pressure of a reciprocating compressor within a certain range? What are the effects of it being too high or too low? For example, before starting our two-stage compressor, we ensure that the inlet pressure at the first stage is greater than or equal to 20 kPa and less than or equal to 80 kPa. What is the purpose of setting the pressure threshold for the primary inlet in the shutdown interlock to be less than 10 kPa but greater than 100 kPa, setting the shutdown interlock pressure for the secondary inlet at 0.6 Mpa, and setting it at 2.43 Mpa for the secondary outlet?
This post was last edited by 156026692 on 2018-8-5 09:15. Let me get started. Generally, a low pressure alarm is set for the inlet of reciprocating compressors; it is less common to have a low-low interlock in place. The purpose of the low inlet pressure alarm or interlock is to prevent an increase in the compression ratio once the inlet pressure drops, as this increases the stress on the piston rod and may affect its normal operation and lifespan. Additionally, low pressure can lead to a too-small reverse angle, and a too-small reverse angle is the most common cause of poor lubrication between the crankshaft and bearing shells in reciprocating machines (this is purely theoretical, as most units do not have the necessary monitoring equipment to measure the reverse angle directly). Additionally, the simplest and most direct reason for setting a high exhaust pressure is that exhaust systems are equipped with buffer tanks and safety valves to prevent the equipment from experiencing overpressure. Of course, regarding the owner’s question about why the inlet is set at a low level while the exhaust is at a high level, there are many other factors involved such as various process flows, inter-stage coolers, air valves, and so on. I won’t list them all here; you can simply search for posts on this topic in the forum – there have been many similar questions posted in the past.