LATEST EXPERIENCE OF COAL FIRED SUPERCRITICAL SLIDING PRESSURE OPERATION BOILER AND APPLICATION FOR OVERSEAS UTILITY

摘要

In the fossil power utility field, a supercritical sliding pressure operation type unit has been developedrnas the most advanced generating system combining higher efficiency, with low emissions technology.rnGlobally, this type of system has been the major trend for recent thermal plants. The use of low graderncoals i.e. low volatile, high ash content, for economic reasons provides additional challenges to meetrnthe international demands for improved efficiency and low emissions.rnBabcock-Hitachi K.K. (BHK) has supplied a number of coal-fired boilers for thermal power plants inrnJapan. The contribution to the improvement of power plant efficiency and the success of reduction inrnNO_x emission has been favourably received by all utilities.rnOur most recent boiler experience relates to 1050MW power plant (Electric Power Development Co.rnJapan, Tachibana-Wan Power Station No.2 boiler; 3000t/h steam output at Maximum continuousrnrating) combining advanced steam conditions; pressure 25.0MPa, temperature 600℃/610℃ andrnachieved the guaranteed boiler efficiency and strict requirements for NO_x emissions and unburnedrncarbon in ash throughout the performance test. Subsequently, a 1000MW power plant (The TokyornElectric Power Co. Inc. Japan, Hitachi-Naka Power Station No.1 boiler, 2870t/h steam output atrnMaximum continuous rating) is now under commissioning, to provide similar advanced steamrnconditions, pressure 25.4MPa and temperature 604℃/602℃. The boiler was designed to meetrnchallenging technical improvements and will be a benchmark for the boilers with High Capacity CoalrnFired Supercritical Sliding Pressure.rnBHK have established a standardised design concept for coal fired supercritical sliding pressurernoperation boilers for worldwide utilities based on our experience of designing and constructingrnsimilar units over the previous decade.rnThis paper describes the principal characteristics of a coal fired supercritical sliding pressurernoperation boiler and suitable design parameters to utilise various grades of coal, consideringrneconomics and reliable operation in accordance with our experiences in Japan and in the exportrnmaker for this technology.