Research On Low Pollutant Emission Retrofit Of 600 MW Unit ESP In Wangqu Power Plant

With the increasing emphasis on environmental issues in China,the emission of pollutants from coal-fired power plants has gradually become the focus of attention.Local and national relevant environmental protection agencies have imposed stricter control requirements on the emission and total amount of pollutants from coal-fired power plants.The promulgation of"Emission Standards for Air Pollutants from Thermal Power Plants"(GB13223-2011)has increased the emission reduction of pollutants from coal-fired power plants in China,and the work pressure on emission reduction has also greatly increased.At the same time,due to the difference in the use of coal,the concentration of dust discharged from the active dust collector cannot meet the new requirements of the country.This puts forward higher requirements fo r soot emissions of new coal-fired power plants or existing coal-fired power plants.Wangqu Power Plant No.1 and No.2 were put into operation in August 2006.The electrostatic precipitator electric field layout method is a double-chamber five electric field.According to the relevant environmental protection standards formulated by the country at that time,the design standards and requirements of the original electrostatic precipitator are relatively low,the designed dust removal efficiency is 99.8%,and the current emission of the precipitator is about 80mg/Nm~3.This greatly exceeds the national 20mg/m~3 or 30mg/m~3 emission requirements.Therefore,it is necessary to carry out relevant transformation of the exist ing electrostatic precipitators.In this paper,the dust collector of 2×600 MW unit in Wangqu Power Plant is reconstructed based on the theory of electric dust deduce index selection,and the effect after reformation is analyzed.Three-phase power supply is used to reduce the emission of traditional single-phase power supplies.After the transformation,the dedusting index becomes larger and higher dust collection efficiency can be obtained.When a five-field electrostatic precipitator is powered by 40 sets of three-phase high-voltage power supplies,the PM10 and PM2.5emission concentrations at the electric dust removal outlet can be controlled below15mg/m~3 and 1.0mg/m~3,and the ratio of PM2.5 to PM10 is 6.5-7.5%or so.By replacing the single-side rapping system of the first and second power plants into a dual-side rapping system,and at the same time adopting the current-limiting optimization mode for the third-fourth-fourth power plant,the electric field flashover frequency is effectively controlled,and the first secondary electric field can be significantly improved.The secondary current,the surface of the cathode and anode plates are clean,the accumulated dust layer is shaken down,the anti-corona phenomenon is effectively controlled,and the power input power of each channel of the electrostatic dust removal is significantly improved after the two-side rapping system is replaced.After the trial test,the effect of the transformation has reached the expected goal and complies with the latest emission standards.