Inlet filter house floor mod increases efficiency, safety
Beatrice Power Station
Nebraska Public Power District
254-MW, gas-fired, 2 × 1 combined-cycle located in Beatrice, Neb
Plant manager: Chris Cerveny
Key project participants: Chris Backer, plant operator Dave Keim, plant mechanic Dave Ruskamp, O&M supervisor
During the winter months, snow accumulation inside the GT inlet filter house created a hazardous environment for plant personnel. The area is accessed when frost buildup occurs on the inlet screens located inside the weather hoods; frost must be removed to prevent turbine trips on high inlet differential pressure. The method of removal is to enter the filter house and brush the screens with a broom. This allows the frost to drop off the screen and fall down to the ground.The problem is that after a heavy snowfall while the unit is online, and from the puffing action of the inlet filter cleaning system, there would be a 4-5 ft snow drift inside the filter house. Drifting was facilitated by the as-designed steel-plate floor, leaving two options for accessing the area: (1) Climb over/through the snow drift or (2) shovel the snow out of the compartment.
One of the plant operators offered what appeared to be a simple and effective solution: Replace the plate-steel flooring with steel-deck grating. The openings in the grating should be sufficient to allow the snow to fall out of the inlet house without any significant accumulation. The next step involved contacting the gas turbine OEM and performing an engineering evaluation.The response to the evaluation was favorable in that they stated there would be no reason why we could not replace the solid floor with steel-deck grating. We happened to have enough grating left over from plant construction, so the cost of implementing this design change consisted only of having a scaffold built to access the bottom side of the inlet filter house in order to remove the original steel-plate flooring (Fig 39).
It is no longer necessary to shovel snow out of the inlet filter house during the winter months, and more importantly, it will not be necessary for plant personnel to climb over the snow drifts. What little accumulation there may be can easily be swept down through the steel-grating floor. This eliminates the need for plant personnel to spend any more time than necessary inside the inlet filter house which becomes quite cold when the outside air temperature is in the single digits and the unit is online.