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[iceman53y]

Greetings, I work in a combined cycle powerplant. We seem to have a problem with the inlet gas pressure balance at our four gas turbines. GT-4 closest to the gas compressors gets the most pressure at its inlet and as we move away to GT-3, GT-2 and GT-1. The gas pressure at the inlet of the gas turbine drops. (Schematic is attached) Discharge gas pressure of the NGC (Natural Gas Compressors) is 677 psi A proposed solution to the problem was to install a balancing line (shown in Red). This would increase the gas discharge header volume by 12 m3. I am not sure what the consequence of adding this line would be. Will it be advantageous? What are the disadvantages.? Thanks.

Attached Files

•  Gas Discharge Header.pdf   60.34KB   40 downloads

Edited by iceman53y, 13 December 2010 - 10:05 PM.

[Zauberberg]

Pressure decrease as you move away from the FG compressor is a consequence of high pressure drop due to flow (if we are not missing something from your post). A "balance line" concept will not help you a lot - unless it is capable of handling that additional flow of fuel gas towards other turbines with acceptable pressure drop. If you have a major DP problem, I'd rather consider replacing the header and feed each turbine directly from the header instead of working out the "balance line" solution.

These balance lines are normally employed between vessels (or between the header/piping and the vessel in order to equalize pressures) and they usually handle rather small flows, if any. If your problems is in undersized fuel gas distribution network, a balance line will not help - unless it can handle that much flow you need with a reasonable drop in pressure as you move through the network.