| Our country’s economy is developing faster and faster,the level of industrialization is higher and higher,at the same time,the consumption of energy is also more and more,the resulting environmental pollution is more and more serious.People begin to pay more and more attention to the comprehensive treatment of NOx（NO,N2O,NO2,etc.）.Thermal power plants account for about 40%of the total NOx emission.Therefore,thermal power plants are one of the main emission sources of air pollution,and also need to focus on remediation.With the development of flue gas pollutant removal technology,sulfur dioxide and smoke have been well treated,and more and more thermal power plants begin to reduce the emission of nitrogen oxides.Based on the research background and the status quo at home and abroad,the comprehensive upgrading of No.1 unit in Pengcheng Power Plant is carried out.The NOx concentration at the chimney inlet of Unit No.1 in Pengcheng Power Plant is as high as 600 mg/Nm3,which can not meet the national emission standard and must be reformed.At present,there are many transformation schemes to reduce NOx emission,and the transformation effect,safety and economy also have their own advantages and disadvantages.Through analysis and comparison,the transformation scheme of low nitrogen burner plus SCR Flue Gas Denitration is determined.This paper mainly analyzes the transformation scheme:first,replace the original burner with DC low nitrogen burner,add sofa air nozzle,and use air staged combustion technology to form a reducing atmosphere to inhibit the generation of NOx;second,install SCR Flue gas denitration device behind the economizer and in front of the air preheater,with ammonia gas as reducing agent and nitrogen and oxygen in the flue gas under the action of catalyst Third,upgrade the main auxiliary equipment of flue gas system,including air preheater,induced draft fan and booster fan,to meet the requirements of denitrification transformation.After the comprehensive upgrading and transformation of denitration,the performance test was carried out on#1 unit to test the transformation effect.Under different loads,the denitration efficiency and ammonia escape rate reached the design expectation,and the NOx emission concentration was lower than 50mg/Nm3,which reached the ultra-low emission standard.After a period of operation,several problems occurred in the revamped#1 unit,such as air preheater blocked by ammonium bisulfate,large reheat steam temperature deviation and low steam temperature,uneven distribution of NOx in denitration system,resulting in high ammonia escape rate.The above problems were solved by pyrolysis ammonium bisulfate,hot primary air leveling test and ammonia injection optimization adjustment.Through the transformation,according to the flue gas volume of 1 million cubic meters per hour and the annual effective utilization hours of 5500,the annual total nitrogen oxide emission of No.1 unit in Pengcheng Power Plant has decreased from3300 tons to 275 tons,and the emission reduction is about 3000 tons.The environmental quality has been greatly improved and the social benefit is remarkable.At the same time,according to the policy incentive of ultra-low emission,the power plant after transformation can produce considerable economic benefits. |
