Research On Combustion Characteristics Of Carbonized Fuel And Air Distribution Technology Of Biomass Hot Blast Stove

In the "Twelfth Five" and "Thirteenth Five" plan, the proportion of industrial boilers is very large and energy saving receives more and more attention. In order to keep the clean of environment, the original coal-fired hot blast stove is transformed into one burning biomass fuels, such as palm thread and straw and so on. Biomass is difficult to storage and transport and has low ash fusion temperature, low calorific value defects, but pyrolysis and charring at low temperature of biomass is one important way of thermochemical transformation technologies which can overcome these challenges and make the energy density and storage effectively of biomass improve. In addition, air distribution modes play a crucial role for fuel combustion. Reasonable air distribution mode determines the length and position of different fire grates and the amount of required oxygen for combustion reaction and plays a key role in bed combustion process.In this paper, the research that the coal-fired hot blast stove is transformed into biomass-fired hot blast stove is entrusted by Danyang Zhongwei New Energy Technology Ltd and its cooperator Taizhou Jinji Dye Ltd in Jiangsu Province. The combustion characteristics of the local biomass is researched and the air distribution mode is simulated. First, the industrial analysis and elemental analysis of palm thread, cotton stalk and straw are analyzed and they are compared with the parameters of the coal. Next we conduct carbonization treatment for biomass and obtain the carbonized samples, then analyze carbon yield and energy yield and measure calorific value of three kinds of biomass. Second, the industrial analysis and elemental analysis of three kinds of biomass charcoal products are analyzed and ash fusion points of palm thread at different carbonization temperature is measured. In addition, thermo gravimetric analysis test is conducted, then the combustion characteristics of palm thread raw material, straw raw material and their charcoal products at different carbonization temperature are compared. Then Coats-Redfern integral method is used to deal with the experimental data to obtain the combustion reaction kinetic parameters. Finally, three-dimensional physical model of furnace for biomass hot blast stove is established and the gas flow and heat transfer process inside furnace is numerically simulated. The influences of four air supply modes on the physical field of the furnace are researched and the best air supply mode is obtained by streamline distribution and velocity contour. In addition, the effects of the flue gas velocity at the secondary air inlet and the number of secondary air inlet on flow and heat transfer are researched besides. The research in this paper can provide theoretical basis and guidance for the improvement of the hot blast stove burning biomass.