Compressors are designed to pump gases only. If, somehow, a vast amount of liquid finds its way inside a compressor, this poses a serious threat to the machine. The video at hand deals with causes, consequences and the detection of liquid carry-over to compressors. It presents three case studies in which PROGNOST systems were able to prevent severe machine damage, and gives advice on what to do to minimize the risk to your machinery.

Vibration and proximity signals related to liquid carry-over
Vibration and proximity signals related to liquid carry-over

Experiences with liquid carry-over

According to our experience, liquid carry-over is a phenomenon much less common than one would initially assume. But, though liquid carry-over to compressors occurs only rarely, it can – due to the basically in-compressable nature of liquids – cause severe damage to the machinery.

There are three main possible causes as to how a vast amount of liquid can get inside a compressor: Liquids may derive from the impurity of other systems, gas condensation in the suction piping, or lube oil. In any case, highly probable detrimental effects on the machinery include serious damages such as cracks, broken rods, pistons, or crossheads.

So, liquid carry-over should be avoided at all costs. Luckily, the vibrational or rod-position impacts of liquids inside a compressor can be reliably detected by monitoring strategically placed sensors. We present three case studies of how online condition monitoring systems helped prevent severe machine damage.

Technical details

Technical details in short: If you suspect a problem with liquid carry-over, always check the crosshead slide vibration and the rod movement at the top dead center and bottom dead center positions. Our systems are able to automatically initiate a shutdown or issue an alert based on uncharacteristically high readings from the pertinent signals, as shown in the video.

Generally, to minimize the risk of liquid carry-over, one should try to avoid liquid process gas, provide a suction drum with a drain system, and check for liquid after a longer shutdown phase.

Click on the video for a more detailed exploration of the liquid carry-over problem, and for how PROGNOST Systems can help you deal with it!