CCI’s Severe Service Valves Stand up to a Hot New Market 

One of the top power producers in China, Huaneng Power needed superior technology for its new coal-fired Yuhuan power plant in the Zhejiang Province. This plant made history in late 2006 when its initial phase went on line, making it China’s first to use ultra-supercritical technologies. Growing economies like China and India are increasingly turning to these new power technologies. When completed, the plant will have four 1000-megawatt plants to feed China’s boundless energy needs.

Ultra-supercritical plants operate at previously impossible steam temperatures and pressures, resulting in energy production efficiencies and lower emissions. This means that valves are exposed to extremely high temperatures. CCI Switzerland’s Sulzer DRE 160 type valve, custom designed for conditions up to 610oC, was the best solution for the plant’s high pressure bypass valve (HPBP).  Also unique to this design is the very short evaporation length due to its inbody desuperheating system, which means that all injected spraywater is effectively evaporated as it exits the valve outlet nozzle. This DRE type of bypass valve is the most commonly used in supercritical power plants.

The low pressure bypass valves CCI supplied to this plant are also from a custom design, based on the well known NBSE60 family. These valves are exposed to the same severe service operating conditions as the DRE valve. Deviating from the HPBP valve design, low pressure bypass valves are usually of an over the plug flow type to protect the condenser. Since the valve internals are not only exposed to thermal stress, but also to mechanical stress caused by friction, all critical internal parts are protected with heat resistant surface treatments.

Published in SOLUTIONS Fall 2007