Using Reciprocating Compressor and Centrifugal Compressor in paralell
Using Reciprocating Compressor and Centrifugal Compressor in paralell
(OP)
Dear Sirs:
At this time I have a Reciprocating Compressor delivering Natural Gas to a 12" pipeline. Can I install a Centrifugal Compressor in parallel with this unit delivering Natural Gas to the same pipeline?. Outlet conditions (Pressure, Temperature, Flow, etc) of both equipments are equal. Will there any trouble with Antisurge System of the Centrifugal Compressor related to nearly discharge of the Reciprocating one?. Do somebody know about this kind of installation in the past?
Regards.
Eng. Orangel Roca
Inelectra S.A.C.A
Caracas, Venezuela.
At this time I have a Reciprocating Compressor delivering Natural Gas to a 12" pipeline. Can I install a Centrifugal Compressor in parallel with this unit delivering Natural Gas to the same pipeline?. Outlet conditions (Pressure, Temperature, Flow, etc) of both equipments are equal. Will there any trouble with Antisurge System of the Centrifugal Compressor related to nearly discharge of the Reciprocating one?. Do somebody know about this kind of installation in the past?
Regards.
Eng. Orangel Roca
Inelectra S.A.C.A
Caracas, Venezuela.





RE: Using Reciprocating Compressor and Centrifugal Compressor in paralell
RE: Using Reciprocating Compressor and Centrifugal Compressor in paralell
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Using Reciprocating Compressor and Centrifugal Compressor in paralell
You are essentially mixing tow different systems. whilst in theory the outputs are the same, the issue is whether the discharge pressure actually stays constant or not. Even a 5 or 10% variation will cause big changes in the flow in either machine. Naturally when flowing two machines, there will be a different discharge pressure than if only one machine is running so I'm not sure how you cope with that scenario.
The anti surge should be within the centrifugal system limits.
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RE: Using Reciprocating Compressor and Centrifugal Compressor in paralell
Since you indicate that the centrifugal compressor and reciprocating one are operating with same flow, I conclude that your centrifugal compressor is operating at a quite low efficiency (considering the area where reciprocating and centrifugal compressors normally overlap). So it would mean that temperatures at discharge of both machines should be necessarily different, unless you have some sort of a very light gas with low compression ratio. And at the end, if you intended to say that both machines have identical "mass flow", because of the different temperatures at discharge the volume flow at the discharge will necessarily be different and you end up mixing different volume flows and temperatures at the common discharge manifold.
Another issue is the pulsations due to the reciprocating one. The pulsations may affect to a certain extent the surge line and operating map of centrifugal compressor.