What causes liquid slugging in a compressor?

Liquid slugging in a compressor can occur due to various factors that introduce liquid into the compression process, disrupting the operation. One significant cause is the compressor inadvertently drawing in liquid ammonia from the suction line. Ammonia, being a refrigerant in many systems, can enter the compressor if there’s a problem with the system design or maintenance, leading to liquid slugging.

Additionally, when lubricating oil is drawn into the suction line alongside refrigerant, it can create liquid pockets that interfere with the normal gas compression cycle. This is particularly critical because compressors are designed to compress gas, and the presence of liquid can cause damage or reduced efficiency.

Furthermore, a rapid lowering of suction pressure can also result in liquid slugging. When suction pressure drops suddenly, it can cause liquid refrigerant to enter the suction lines rather than vapor, as the vapor might not be able to keep up with the reduced pressure and flow conditions.

Thus, all of these factors—drawing liquid ammonia, drawing lubricating oil, and a rapid decrease in suction pressure—can contribute to liquid slugging in a compressor, making the comprehensive answer the correct choice.