Numerical Simulation Of The Swirling Burner Combustion In Power Station Boiler

The capacity of the power station boilers equipped swirling burners accounts for 20% of the total capacity in our country. In the years of 1970', direct flow burners are widely used in China, and swirling burners are almost neglected, furthermore the general power stations burn the coal Q_net,ar > 168Mj/kg,V_daf > 25 % . Swirling burners are newly recognized with along the problem of flue gas temperature deviation of furnace exit exposed in large tangentially-fired boilers. Many large boilers abroad, such as, B&W company , Gernamy, Japan, use swirling burners and get good coal adapability as well. Compared with direct flow burners, swirling burners have the advantages in the respect of convenient installation, even load in the furnace, even flue gas temperature and velocity of furnace exit, small deviation of superheater temperature, and the reducement of the superheater and reheater top point temperature, reducement of slagging tendency.In recent years, with the development of large capacity and high parameter unit of power station in our country, and the introduction of advanced large boiler manufacture, some new technology of swirling burners are used much more in the power stations. However, the character of coal in our country is different from that of foreign countries, so it is very imperative to master the design technique and function charaters.This paper first analyzed the situation of the coal used in power stations and main problems of the burner technology, and introduced the application of direct flow burners and swirling burners in power stations. Then the paper introduced the research status and development tendency of the simulation of boiler combustion, and especially introduced some numerical calculation methods.Then the paper summarized the structure and combustion character of some typical swirling burners in common use in home and abroad, and combining the function achievement of several large boilers in our country, compared the character of swirling burners and direct flow burners, and analysed the development tendency of swirling burners.Finnaly, the paper simulated the combustion process of the researched boiler, calculated the different combustion according to different swirling intensity, differentshade ratio, OFA, and different coal fineness. Through the numerical simulation of temperature field, oxygen concentration, emission of NOx, The paper compared and studied the combustion characteristics, slagging tendency and NOx emissions of swirling burner. The result will optimize the boiler function.