The Feasible Analysis And Research To Reduce Exhaust Flue Gas Temperature Of 660MW Ultra Super-critical Boilers

Boilers are the most ordinary pyro-installation.The reduetion of the exhaust gas temperature Plays a significant role in security, economical operation and energy saving for boilers.In along with the Chinese economy fast development, the electric power demand day by day is exuberant in recent years. Newly built design teams are ultra supercritical and ultra supercritical units. This article introduced the conditions of the flue gas temperature higher of the NO.1 boiler in AnHui HuaDian WuHu Electric Power Corporation Limited,analyzed the factor of the flue gas temperature higher from the burning adjust, worked out the technology plan of feasibility, and provide the reference for the deepest reduce the temperature of flue gas of 660MW ultra supercritical set.so that its high exhaust gas temperature, the problem of slagging and low thermal effieiency should be solved in the research. In the dissertation,at first,the reasons of high exhaust gas temperature and its resolvent were analysed deeply, Based on a lot of literatures and projects, integrated measurement of boiler, iniegrated thermodynamic calculation and analysis were performed. There was a conelusion that the quantity of heat transfer of air preheater could play a significant role in reducing exhaust gas temperature was set up, and academic basis in low air preheater design was accomplished at the same time. Based on references and calculation conclusions,and spirally finned tubes were chosen instead of bare tubes to compose the new designed economizer. Construction and major parameters were calculated detailedly, and the conclusion showed that spirally finned tubes economizer was low height, excellent efficiency in anti-attrition, and outstanding capability in heat transfer, and many advantages such as simple structure, low investment, and easy to maintenance. So the introduction of spirally finned tubes economizer can increase the quantity of heat flux of economizer, and can produce the reduction of exhaust gas temperature and hot air. Further, burning temperature in boiler decreased, and the problem slagging in furnace would be relaxed.The new designed air preheater was set up into the boiler. For checking the efficiency, heat balance of boiler was measured before and after reformation respectively. The conclusion shows that, after reformation, the thermal efficiency had improved as 2.27%, and exhaust gas temperature had decreases as 15℃respectively. All of these can drive positive effects on the conditions of boiler, and reduce slagging problem. When the practice of No.1 boiler is concerned, it can run steadily at a load of 120 to 130t/h in a long-term period, to reduce the net coal consumption rate about 2.05g/kWh, decide on the basis of 70 a hundred million the quantity of electricity per year, When the economic benefit is concerned, 14,350 tons coal can be saved per year in two boiler, which would be excellent engineering effect. At present, the achievements have been applied to the other boilers in our power plant.