2016 BEST PRACTICES: MPC Generating

Hydrogen system supply redundancy

Challenge. MPC Generating is a simple-cycle peaking plant with a crew of five technicians and normally is staffed Monday through Friday from 0700 to 1730. The facility has two W501F gas turbines; one of the generators is hydrogen-cooled.

Hydrogen normally is supplied to the generator from a bank of 12 bottles. A pressure gauge is located at the hydrogen supply bank and an operator records the pressure during daily rounds. The hydrogen supply bank is changed when the pressure falls to approximately 300 psig which is typically a couple of days’ supply.

One weekend, a sizable swing in ambient temperature caused a significant increase in hydrogen consumption; the resulting low-pressure condition in the generator tripped the unit.

This event also triggered the hydrogen generator to auto vent, making the unit unavailable for several hours while the generator was purged with carbon dioxide and recharged with hydrogen.

Solution. Staff designed and installed an independent emergency hydrogen supply line with a separate and dedicated redundant hydrogen supply bank. The emergency hydrogen supply is clearly labeled so that it will not be mistakenly used as the normal supply bank.

The redundant supply line is parallel to the normal supply line and has a separate pressure regulator that is set 10 psi less than the normal hydrogen supply line pressure of 70 psig. If hydrogen supply pressure drops to 60 psig, the emergency bank will provide hydrogen to the generator.

Results. Since the addition of the redundant hydrogen supply the plant has not experienced any forced outages caused by low hydrogen pressure

Project participants:

James Goins Jr, O&M manager

Chris Harris, lead technician

Scott Hobbs, lead technician

Charles Gibson, lead technician

Nick Sanz, technician II

Gavin Spann, technician II

Bly Crane, plant administrator

MPC Generating LLC

Owned by Southeast PowerGen LLC

Operated by Cogentrix

380-MW, gas-fired, two-unit, simple-cycle facility located in Monroe, Ga

Plant manager: Mike Spranger