Simulation of Reciprocating Compressor Start-Up and Shut down under Loaded and Unloaded Conditions

Vasillaq Kacani


During the start-up and shut down phase of reciprocating compressors the loads on all components of driven train system are very high. In this paper a method for the calculating the forces on coupling, e-motor, crank shaft as well other components of the system will be described. The modelling of the electrical induction motor, coupling, crank shaft, damper as well as the compressor resistance torque are extremely important in simulating start-up and shut down of reciprocating compressor. Equally important, are the switching torque of the electrical motor and the instantaneous moment of inertia of the reciprocating compressor crank gear. The transient start-up and shut down process under loaded and unloaded is described using a non-linear differential equation for driven train system: EMotor – Coupling – Flywheel – Reciprocating compressor - Damper. Shaft torsional moments on the drive train and especially on the coupling, whether elastic or stiff, can then only be calculated using numerical simulation.