Gravity-filter nozzle support design
Morgan Energy Center
800-MW, gas-fired, 3 × 1 combined-cycle cogeneration facility located in Decatur, AL
Plant manager: Mike Gough
Key project participant: Scott Parker, operations manager
Morgan Energy Center (MEC) awarded the OEM a contract to refurbish one of four gravity water filters. Complete refurbishment of the one filter included replacement of all media and nozzles. Since then the site has been troubled with nozzles detaching from the laterals, allowing filter media to enter and plug the backside of other nozzles thus reducing the efficiency of the cleaning cycle. The plugged and or missing nozzles resulted in:
- Reduced filter operating hours.
- Filter downtime to evacuate media to replace the liberated nozzles.n Increased filter maintenance.
- Poor water quality.
- Reduced filter throughput.
- Reduced filter cleaning caused by media bed compaction.
- Excessive fines accumulation.
- Channeling. These combined effects severely hampered production of filtered water.
A design was engineered and tested for durability and flow restrictions that would eliminate nozzle liberations without reducing gravity-filter performance. This included designing a test header with OEM nozzles and numerous restraint test devices. A solution was found after extensive testing and was implemented in an actual filter.All the media beds and 450 nozzles from the gravity filter were removed. We then installed new nozzles with the addition of a small amount marine epoxy to each nozzle on the mating surfaces of the nozzle and the lateral.Then, upon completion of the nozzle installation, we added a Type 304 stainless steel angle ranging from 2 to 10 ft across the top of the nozzles and secured the angle to the bottom lateral header. The media then was replaced over the supported nozzles and filter placed back in service.
This cost-effective design enhancement had immediate positive results. We have not had any nozzles detach from the laterals to date. Also, the unit now has consistent filter cleaning without compaction or channeling.This design improvement has resulted in increased filter water throughput and increased filter run time between cleaning cycles while maintaining sufficient water quality. MEC plans to apply the same design for the other three gravity filters.