Research And Engineering Practice Of Wet Electrostatic Precipitator In Coal Fired Power Plants

The fundamental status of coal in China’s energy consumption structure will not change in the short term, but our country is facing the dual constraints of energy security and environmental security, clean coal is the only way for China’s energy development. As a large family in coal consumption, coal-fired power plants have become a top priority in China to promote clean coal technology. With the strict environmental standards and policies of coal industry, the transformation of coal-fired power plant ultra-low emissions rises. To achieve ultra-low emission coal-fired power requirements, a wet electrostatic precipitator (WESP) terminal as the core control technology came into being.This paper discussed and research the current mainstream ultra-low emission coal-fired power transformation route systematically, carries in-deep analysis on its technical characteristics, scope and other. Combined with the current application status, it describes the technical principles of the domestic three main types WESP, structure type, suitable conditions and in the promotion of the application of coal-fired power plants, and taking three types of WESP for a more comprehensive comparative analysis.At the same time, take the country’s electricity in a power plant demonstration project for example, gives a typical conductive fiberglass WESP technology design, this scenario will unite as a phase-change option, Improve Efficiency means the first industrial application of practice. We also analyzed the impact of various design factors (layout, the structure of the inner member, etc.)in WESP from the stability of the dust demisting efficiency, plant operation and other aspects, provide analytical basis for the emergence of various problems in engineering practice; for legislation formula WESP structural characteristics, the main body of the WESP steel frame, housing, sump were optimized, then as a standardized reference implementation; system optimization WESP cathode line technology, to explore the combination of theory and practical application really suitable for WESP cathode lines form, material and fixed framework forms; by CFD numerical simulation and field tests continue to improve, optimize and improve the WESP internal velocity field, pressure field, adjusting means (baffles, rectifier grille) and the like.Finally, this paper analyzed the effect of the WESP industrial applications systematically. Through the system test site after practical effect of WESP put into operation, to verify the WESP can achieve stability requires that the current ultra-low emissions of soot, wherein the phase change condensation, etc. available as an option to improve the WESP for fine particulate removal capability. The actual test results show that after the WESP commissioning, particulate emission concentration for only 1.589mg/m3 (load 600MW, voltage 60kV),1.265mg/m3 (load 500MW, voltage 60kV). By economic analysis on WESP industrial application, large-scale coal-fired power plants using WESP means dust deep transformation, benefit from price subsidies and other policies, in accordance with the dust emission concentration <10mg/m3 execution,630MW,1000MW unit can be 18 to 23 years cost recovery; in accordance with the dust emission concentration <5mg/m3 execution,330MW generating units above designated size 3 to 5 years to recover the costs.