Research On Operational Technical Specification For Flue Gas SCR System Of A Thermal Power Plant

The implementation of the new emission standard of air pollutants for thermal power plants(GB13223—2011)makes that the SCR(selective catalytic reduction) system becomes the standardized flue gas denitrification device for the most thermal power plants in China.However, the application of flue gas denitrification technology started rather late in China, with short operationaltime and insufficient operational experience. The studies on the associatedoperational technical specifications are demanded.This thesisspent four years in tracking the operation situation of ~100 thermal power plants. Based on the summarization and analyses of the operational experience of flue gas SCR system of those power plants,a standard entitled Operational Technical Specificationof Flue Gas SCR System for Thermal Plants(DL/T335—2010), which can be applied to any SCR-equipped thermal plant was developed.The specification consists of ten chapters and three informative annex,providingparticular stipulation for the whole operational process including the startup and stop of denitrification systems.In the chapter regarding to theoperation adjustment,the concept of economic operation is introduce inthe first time of SCR operation. That is,in the process of operation, the ammonia consumption should be decreased as much as possible,under the precondition of meeting emission control requirements.The specification sets the stipulation for the handling of primary trouble-shooting. When a primary trouble occurs,oneshould handle it correctly and debug it quickly to recover the productionaccording to the specification,to ensure the personal and device safety.It also sets the stipulation for the safe operation of reducing agent preparation.In operation, special attention must be paid tothe protection of catalystto void the combustible oil and coal dust to stick to the surface of catalyst,which will get catalyst burned out.Be sure to check the catalyst when the unit stops,and supplement the catalyst in time if the catalyst activity reduces. At the same time,consider about catalyst regeneration prior to the supplement.Due to the great quantity of heavy metal in the catalyst,wrong handling of replaced catalyst will cause a secondary pollution to the environment.The replacedcatalyst should be handed over to a specialized company for harmless disposal.The specification fills up the domestic margin in this area. A thermal powerplant could formulate an operational brochure referring the specification while taking account in the traits of the unit for the front-line SCRoperational workers.