Numerical Simulation Of Soot In The Furnace Of Coal-Smokeless Combustion Boiler

In China, small industrial boilers consume a lot of coal and the combustion efficiency is very low. A great deal of black smoke releases from them. The main component of the smoke is soot. Soot not only influences the entironment, but also harms our health."Coal-smokeless combustion technology" is a new combustion technology aiming at the existing problems of small industrial boilers. The principle of thin coal layer gasification with low primary air velocity is adopted at the bottom of the furnace and staged secondary air, staged combustion and gas-solid separating technology are adopted in the upper space. This technology applies to mechanical grate coal-fired boiler. In the practical running process, dust emission is reduced on a great degree and soot formation is availably restrained.The numerical research subject adopted in this paper is a coal-smokeless combustion entrained boiler. Combined with increasingly consummate computational combustion theory, soot produce in the furnace is simulated. In this simulation, "black box" model based on thermal dynamics equilibrium is adopted to deal with coal combustion reaction on the grate and Realizable k ?εmodel, eddy dissipation approach and discrete ordinate method are accepted to deal with gas turbulent combustion over the bed. Through numerical simulation, velocity field, temperature distribution and species concentration distribution in the furnace are obtained.Based on these works,"postprocessor"is employed to numerically simulate soot under different operating conditions. The simulant results prove the obvious effect of"stratified and staggered impinging stream type multiple-nozzle secondary air"on eliminating soot in theory and the design operation condition is reasonable.