Reduce Shiliquan Power Plant 125mw Unit Boiler Flue Temperature

The boiler is one of the most important equipments in electric power plant. In the thermal loss of the boiler, the waste heat loss is the bigge stone, about 5% ~ 12% in general, and about 60% ~ 70% of all the boiler thermal loss. The main factors that influences the exit thermal loss is the exit gas temperature. Higher exit gas temperature is always the main factor that influences the thermal efficiency of the boiler and the generate electricity cost of the unit furthemore. Reduce the exit gas temperat ure will save fuel, increase plant efficiency,decrease the costs of the power plant and reduce the air pollutions. This has the large economic and society benefits.Around the higher temperature of boiler in shiliquan power plant, the thorough research works are carried in this paper. Firstly, the various fa ctors which causes high exit gas temperature are proposed and analyzed in theory. Secondly, based on the the present condition of 125MW boiler, according the change of the coal, equipments, running parameter and style, thermal calculation for combustrution and heat transfer is carried. From the calculation result, we know that the theoretical exit gas temperature o f 125MW boiler can reach 148. 5℃ under present conditions (and which 170 ℃ in boiler design calculation books ) . Theoretical support is provided f or the research of hereafter. In the foundation of calculation, aim at the higher temperature of boiler, the possible reasons are analysed. Throughing the thermal experiments and calculation and analys, the main re asons of the higher exit gas temperature are conformed. For further lowe ring the exit gas temperature , we can add the low-pressure economics.According to the above conclusions, we primarily proceed researche wo rks.Comprehensive reform of the mill system, with the first coal separat-or and renovated experiments for the point, is carried out. As a result, impr ove the efficiency of the separator by 10%, and increase the lift of mill system 8 ~ 10 t/h. Design and add the low-pressure economics in the eExport of the air preheater, through experiments and analysis, the best ru nning way are determated, and the improving measure are put forward for the questions in design toguide the future work. Adopt the new craft and method to dissove air leak of the furnace wall and ash amassing on the he at ing surface or ash clogging the heat transfer of air preheater.Through the reaserch work foe the lesson , reconstracts project are given up and carried out during the major repairs of the #3 boiler in October 20 03, also the favorable effect obtained. Under the conditon of the low-pressure economics running, the exit gas temperature are lowered from 192. 5 V to 147. 5 Vsuccessfully, under t throwing low-pressure economics, the exit gas temperature reduce to 134.1 V furthermore (under the enviro-nmental temperature about 10-15 V ). we get better economicbenefit.Reducing the exit gas temperature of bioler is a comprehensive and systemic work. Factors which influent the exit gas temperature are variousin different unit. This paper will give helpful guide in theory and practiceto shiliquan power plant and other power plants to reducing the exit gas temperature of 125MW unit.