Theoretical Rearch And System Development Of Reciprocating Compressor Stepless Capacity Control

Reciprocating compressors have a wide range of applications in the petrochemical industry. With the constant changing in petrochemical processes and increasingly energy tensions in worldwide, it not only requires that the capacity can be a continuously adjusted in greater range, but also the power consumption decreased proportionally with the capacity reduced. Among all capacity regulation methods, pressing-off the suction valve is widely favored by industries because of its advantages of full-range stepless adjustment and good economy.This paper does a research on capacity regulation by the method of pressing-off suction valve, including1. A mathematical model of reciprocating compressor working process was established, through that the changing of cylinder pressure, suction and discharge valves motion under normal and capacity regulation conditions was analysised.2. By simplifying the working process of capacity regulation condition, an approximate calculating formula for capacity was derived, having some reference value.3. Through CFD analysis of the reciprocating compressor working process under capacity regulation condition, the gas-force on suction valve was calculated, and factors which affect the gas-force was analysised. 4. The changing of impact velocity between suction valve plate and valve seat under capacity regulation condition was analysised, the results show that the valve life was affected because the impact velocity significantly increased under capacity regulation condition.5. A reciprocating compressor capacity regulation system was designed and built. For the shortcomings of press-off suction valve on part stroke, a new scheme, pressing-off suction valve spaced by cycle, was designed, the influence on valve life was effectively reduced.