1 reply to this topic

[CHEMSTRONG]

Hi,

 

I am emulating centrifugal compressor which is driven by variable speed gas turbine..

 

Compressor antisurge control algorithm , load sharing control, and performance control is built in Unit Control Panel of vendor..There is a flow element orifice installed at compressor suction which measures delta P across the orifice...Antisurge algorithm takes inputs as suction pressure, orifice delta P and discharge pressure...need your inputs as to how to implement antisurge and load sharing  logic - any standard procedure from experience...

How proximity to surge is calculated and how set point is passed to antisurge controller?

 

 

Thanks,

Chetan Chavan

[Zauberberg]

These are normally calculations provided by the original equipment manufacturer - I wouldn't dare to do them myself no matter how much confident I feel with my simulation skills. The reason: mistakes can be so expensive.

 

The basis is in calculating actual suction volume flow, for which the relevant parameters are extracted from transmitters and passed through a calculation block. For any given compressor speed, the actual surge point is already known on the compressor map. What the controller does is to add (usually 10% or 20%) more flow from the actual surge point to define the set point for ASV controller at given speed of the compressor.

 

Load sharing works on a similar principle. Control system calculates the actual horsepower of each machine based on operating conditions and then minimizes delta value between the machines.