99/00670 Investigation on fluidized bed combustors with even or uneven distribution of fluidizing air

Abstract

This paper has studied the characteristics of particle dispersion and combustion of high moisture fuels in fluidized bed boilers with even or uneven distribution of fluidizing air. The cold tests show that the diffusion and mixing of the combustibles in the sand is much better for the revolving bed with uneven distribution of fluidizing air than traditional bubbling bed with even distribution of fluidizing air. These characteristics are useful to improve the moisture evaporating and the fuel burnout process. The hot test of the bubbling bed shows that the moisture has significant effect on the combustion and emission. The bed temperature and NOx emission decrease with the moisture increasing. The hot test of the revolving bed indicates that the bed temperatures are well-distributed in the shallow fluidized bed and the combustion stability can be maintained easily. At the same time, a numerical three-dimensional model which takes account of fluid flow and particles movement in fluidized beds was developed to predict the behavior of fuel particles in the sand bed. The calculated results were compared with the test data.