Emerson Process Management’s Fisher® Control-Disk™ valve has improved backwash flow control within the water-treatment system at E.ON’s combined-heat and power (CHP) plant in Northwich, Cheshire, UK. The resulting elimination of filter media losses and subsequent downtime has enabled E.ON to reduce costs and improve availability as it provides steam for two local soda-ash plants.

The E.ON CHP facility is one of the largest of its type in the UK, generating 130MW of electricity for local residents and capable of supplying approximately 500tns of steam every hour for two nearby soda-ash (sodium carbonate) production plants in Winnington and Lostock. Make-up boiler feed water is obtained from the River Dane, cooled and pre-treated to remove any algae or silt, then passed through one of six filters before being sent to a holding tank.

The filters are cleaned by air scouring and backwashing to remove any material blinding the filter. E.ON installed an eight-inch Fisher Control-Disk rotary valve to replace the original butterfly valve. The new valve has dramatically improved backwash flow control without compromising capacity at peak demand. Since it was installed, the plant has not lost any filter media or experienced any downtime due to water filter problems.