Numerical Simulation Of Air-staged Combustion For A Pulverized Coal-fired Boiler Furnace In One-dimensionality

Coal is the principal energy resource in China. The result in the severe environmental pollution due to coal combustion restricts the development of energy industry. It is good for development of the national economy by increasing the efficiency of the boiler, decreasing the occurring of the blowout of the pipes, and reducing the let of the pollutant and so on.Development of coal combustion technology in the past was largely empirical in nature, being based primarily on years of accumulated experience in operations of utility furnaces and on data obtained from sub-scale test facilities. Empirically based experience and data have limited applicability. With the fast development of computer, the numerical simulation of combustion has been an important means of the combustion theory research and the combustion device design.Through computer numerical simulation, this text carried on computational analysis about velocity field, temperature field, density field and the trajectory of the particles in the chamber .As to the gas phase flow field, this text chooses k ?εequation model. The form of k ?εequation model relatively simple, needs little CPU time and it can reflect flow characteristic better of burner, had made more rational velocity field. Adopt the track model of particle on simulating trajectory of the particles of the two phase flow. This text deals with the turbulent diffusion with stochastic tracking approach.The results show that air-staged combustion with wall-set over fire air postpones the mixture of pulverized coal and air which delays the ignition and combustion in the furnace and lower the speed. The temperature level in the furnace, the furnace exit gas temperature and the wall temperature decrease and the flame center of shifts lower. The NOx emission in the furnace decreases obviously and the maximum NOx reduction efficiencyηNOx can be up to 35.12%.