Aerovent Keeps the Dust Away at American Electric Power
Reducing maintenance costs and nuisance shutdowns of the boiler feed water pumps was the goal of American Electric Power’s Clinch River Plant near Cleveland, Virginia.
Airborne fly ash dust was being drawn into the Boiler Feed Water Pump Room. The lubricating oil vessels for the pumps are under a slight vacuum and the dust was pulled into the vessels and settled into the oil. This caused maintenance problems with the pump seals.
The dust was also causing electrically controlled hydraulic valves to trip, resulting in nuisance shutdowns of the pumps. In addition, the room had a high heat load due to the steam used to drive the pumps.
The Boiler Feed Water Pump Room is roughly 60' x 75' x 25' high and is located deep within this 750 megawatts coal fired power plant. The room has no walls or ceiling exposed to the outside. The room was hot in the summer and dusty year round.
Engineering helped evaluate estimates of heat load, wall openings, room size, possible locations for fans and filter cabinets, ductwork routing, and air flow required to positively pressurize the Boiler Feed Pump Water Room with clean outside air. This application evaluation lead to the recommendation of two (2) Aerovent 35" BI-SWSI-1223-30 centrifugal fans with size 48 filter cabinets, each to move 21,000 CFM of air 5" w.g. static pressure.
Two (2) fan filter cabinet assemblies were selected for redundancy and the ability to run one fan/filter system in the winter and two systems in the summer. The location of the fan/filter assemblies was chosen for ease of service, availability of relatively clean air, and space considerations. The challenge was that the fan/filter assemblies needed to be located over 200' away from the Boiler Feed Pump Room.
Dave Leclerc, Vice President of Sales for Aerovent, suggested that the fans and filter cabinets be consolidated on two (2) unitary bases with solid transitions from the fan inlets to the filter cabinets. This design ensured a solid fan and filter assembly that was easier to install and that should provide trouble free service. Each fan and filter assembly was mounted on vibration isolators on a roof mounted steel platform.
The ductwork, platform, and installation were the overall responsibility of Michael Nolen of H. C. Wade sheet metal works, a long-time Aerovent customer, with installation done by Morgan Mechanical.
The Boiler Feed Water Pump Room openings were eliminated as much as practical to allow 21,000 CFM of air to put the room in a positive pressure condition. This assures that free-floating dust will not migrate into the room and be pulled into the lubricating oil vessels. The cleaner environment in the room will also reduce the hydraulic operated valve problems that were previously caused by the dust.
The Aerovent fan and filter systems were started up smoothly in December 2003, and the initial reports are “clean!”