EMS Inc. / Alberta / Canada / Case Studies / Inter Stage Pressure Drop and High Compressor Rod Loading

Inter Stage Pressure Drop and High Compressor Rod Loading

Unit: Ariel JGW-4 2 Stage field booster compressor.

The unit was reported operating under recycle conditions.  The required unit sales capacity had not been affected due to the operating condition the unit was under.  As far as the operations were concerned, this unit was meeting expectations for providing capacity for the site.  Over time, compressor discharge temperatures did not increase to an alarm level on the panel and the increase noted after a historical review was very slow.

By evaluating the unit performance online, the EMSi analyst was able to ascertain that there was a rod loading issue on the 1st stage throws of the compressor and that the cause of the high rod loading was increased ratio across this stage.   Pressure drop from the first stage discharge to the second stage suction was determined to be 66% of discharge pressure!  By using over 20 years of analysis experience, the analyst was able to pin point the source of the pressure drop to be a plugged filter screen in the 2nd stage suction system.

This was all completed without taking the machine offline or incurring any outages.  The machine was scheduled for a shutdown and the restriction was removed with a minimal amount of downtime.  The compressor cylinder load settings were also adjusted per the analyst’s recommendations to reduce the amount of gas flowing through the recycle loop of the machine during the same outage.  Also, panel protection for differential pressures on the stages did not alarm and there was potential for increased internal rod loading.  This could accelerate reciprocating component wear and potential future damage.

With these optimization improvements, the unit performance was improved and the wasted horsepower and excess fuel gas consumption were minimized.  Operational experience and unit performance are key factors in the ability of EMS Inc. to provide industry leading service.

Inter Stage Pressure Drop - Compressor Analysis Alberta
Compressor Performance Analysis Data