Practice And Research On Increasing The Efficience Of The Dust Collector Of The Large Thermal Power Unit

Coal soot emissions are one of the main causes of the haze.Soot emissions of the boilers of Coal-fired power plant accounted for 35%of total emissions,cause serious influence to atmospheric environment.Practicing and researching on reforming the effect of electrostatic precipitator of large thermal power unit has good theoretical significance and important engineering application prospects.This thesis describes on the electrostatic precipitation technology at home and abroad in detail.Through the investigation and study,the thesis analyzes and demonstrates the feasibility of the unit electric retrofit scheme of No.1 and No.4 unit of Wushashan Power Plant.Rotating electrode and high frequency power supply of the 1st~2nd electric fields technology is used in this effect modification to the electric of No.1 unit,as the target of soot emission below 20 mg/Nm~3.Its effect is contrasted to the high frequency power transformation of No.2 unit;High frequency power supply,pulse power supply and wet electrostatic precipitator technology are used in this effect modification to the electric of No.4 unit,as the target of soot emission below 2.7 mg/Nm~3.In the thesis,the author describes the implementation process and measures of the scheme,analyzes the problems existing in the renovation,tests the modification effect,summarizes the various factors influencing the effect and the engineering experience.Through the comparison of test results of No.1 and No.2 units,it is found that the outlet concentration of the dust collector is reduced from the original 50mg/Nm~3 to 22~24mg/Nm~3,but it still need the second level of the desulfurization system to meet the new emission standard.After the renovation of the high frequency power supply and the rotating electrode technology,the performance test shows that the outlet concentration of the dust collector is below 10mg/Nm~3.Comprehensive consideration of the factors of equipment defects,reliability,operating conditions and the second level of the desulfurization system,the high frequency power supply is suitable for 30mg/Nm~3standard.For the standard of 20mg/Nm~3,it is a suitable method to consider the combination technology,such as the combination of"rotating electrode+high frequency power supply".Through the test,it's found that the technical scheme of"high frequency power of the1st~3rd electric fields+pulse power supply of the 5th electric field+wet ESP",can meet the discharge standard of 5mg/Nm~3,even 2.7mg/Nm~3.Transformation meets the standard in the short term,but its long-term effect need to be verified by the long-term operation of the equipments.After high frequency power of the 1st~3rd electric fields and pulse power supply of the 5th electric field,the output of dry dust collector is 24.9 mg/Nm~3 in the case of the maximum output power.After high frequency power of the 1st~2nd electric fields on No.2 unit,high frequency power supply adjustment to the maximum output can reach this level.Taking the 2nd level of the desulfurization system and the new wet ESP into account,in the future,implementation of the"near zero emissions"should be appropriate to reduce the power of electric power transformation to avoid over-investment.Through the practice and research of the No.1 and No.4 units of the dust removal projects of the enterprise,the thesis summarizes the experience and problems,which will play a good role in the future of environmental protection.At the same time,the research results can provide a reference for the dust removal equipment of other power plants.