| In recent years,with the rapid development of economy,the environmental problems became more and more prominent,and phenomena of pollution haze are frequently found in autumn and winter.Because of this,Chinese government has promulgated a package of policies and measures to control air pollution.Coal-fired power plants and industrial boilers are the main source of air pollution.Electrostatic precipitators(ESPs)as one of the main dust control equipment in electric power industry,its conventional technology are not able to meet the recently national environmental protection standard.Facing with rapping re-entrainment problems existing in conventional ESPs,some manufacturers put forward different kinds of new technology,such as low-low temperature ESPs,moving electrode technology,electrostatic-fabric integrated precipitator,flue gas conditioning etc.Nevertheless,this paper proposes a new technology of high efficiency and low cost-Isolation-Rapping Technology,that means to close airflow passage to stop flue gas moving into that section while rapping CE system here,after consecutive rapping to make clean surface of collecting plates,achieving to control rapping re-entrainment,ultimately to improve ESP with high efficiency.This paper first introduce current research status of isolation rapping technology in domestic and overseas,then analyze main factors affecting ESP efficiency and performance by study conventional ESP structure and working principles.Base on above,the paper probes into an effect of rapping re-entrainment to dust collecting efficiency.And next step is to analysis and compare present feature of different rapping re-entrainment technologies.After studying the principles and structures composition of isolation-rapping technology,the paper discussion focuses on actuator,consisting of its preliminary design,reliability test,tapping on the top beam,precautions for reduce air leakage rate after analysis situation.Based on the research and study aforementioned,and the analyzing of plant requirement,present situation and recent research studies,the paper offers a proper ESP engineering proposal with two-stage technology and isolation-rapping technology for#1 unit ESP retrofit in Xuancheng Power Plant.Meanwhile,during the installation period,reasonable solutions for isolation-rapping technology application at site installation are given during site assembling,to ensure successful completion of the project.After ESP improvement,a performance test was conducted by the owner to check the ESP collection efficiency.The result shows the ESP outlet dust emission is only 27.1 mg/Nm3,which is lower than State Requirement of Environment Protection.Isolation rapping technology,combined with high-frequency transformer,two stage technologies,ultimately accomplish the goal of ESP with "improved efficiency" and "Energy saving". |
