Fisher valve improves filter water flow control at power plant

  • June 17, 2010
  • Emerson Automation Solutions
  • Case Study
June 17, 2010 - 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 500 tons 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. The facility has had problems controlling this backwash flow. The original butterfly valve used in this process could not provide a steady flow rate, causing media to be lost through the filters. As a result the filter media had to be replaced or refilled at an average cost of £3,500 a year. The downtime for this maintenance also affected the plant’s ability to meet its steam requirements. 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. The improved performance reflects the Fisher Control-Disk valve's unique disk profile and true equal-percentage characteristics that enable it to adapt to changing process conditions and to provide control over a wide range. The valve provides between 15% and 70% travel without compromising capacity. This performance represents a significant improvement compared to standard butterfly valve designs that offer 25% to 50% of travel. Neil Price, Improvement and Performance Coordinator, E.ON, said, “The Fisher Control-Disk valve not only controls the backwash flow rate more accurately, but also it delivers, when 100% open, a flow rate adequate to meet the water plant demands, without restrictions. Its performance and reliability led to savings of £3,500 a year and enabled us to improve our customer service.” About Emerson Process ManagementEmerson Process Management, an Emerson business, is a leader in helping businesses automate their production, processing and distribution in the chemical, oil and gas, refining, pulp and paper, power, water and wastewater treatment, metals and mining, food and beverage, life sciences and other industries. Fisher technology and innovation in final control systems plays a key role in the Emerson mission of combining superior products and technology with industry-specific engineering, consulting, project management and maintenance services. Emerson brands include PlantWeb Syncade Fisher Micro Motion Rosemount Daniel DeltaV Ovation and AMS Suite. About Emerson Emerson, based in St. Louis, Missouri, USA, is a global leader in bringing technology and engineering together to provide innovative solutions for customers in industrial, commercial, and consumer markets through its network power, process management, industrial automation, climate technologies, and appliance and tools businesses. Sales in fiscal 2009 were $20.9 billion. Learn More

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