Turbocompressor Load Sharing Control

[rafcu]

Hello Guys,

I’m working on a new project where there are 6 equal turbo compressors in parallel to compress natural gas. My problem is that the customer wants install a sophisticate Load Sharing Control (LSC) to control individual inlet flow compressor via the driver operating limits and working in cascade with the compressor speed as final control element.

The driver limits impacting on the control are: turbine speed, exhaust temperature, air compressor speed, etc.

From my opinion as the compressors are similar, to perform the LSC is enough to control, for each compressor, the distance to the surge control line, balancing out each compressor operating point.

Could anybody advise about the subject?

In addition, does has any body experience related with the sequence to start up three turbo compressor in parallel?

Thanks,

Rafcu

 

[pmover]

yes,

i would definitely give load sharing control due and close consideration, including all possible operating scenarios (i.e. start-up, shutdown, 1, 2, 3, etc. unit operation). basically, lsc are for similar centrifugal compressor units operating in parallel mode and it is accomplished by rotor speed or otherwise. as far as the driver limitations, these limitations are controlled by the driver control system and not the surge and/or load sharing control system. the lsc simply sends output signal to driver for making adjustments in compressor operating point. one matter to consider is the piping system. this mainly pertains to the tuning of the control system, but if not planned/designed correctly, there may be operational constraints.

the mfg of lsc do have technical articles that explain the process of lsc and provide justifications. the mfg should be willingly provide this information.

hope this helps - please advise.

good luck!
-pmover