S, N Release and Partition in Pyrolysis during the Process of Coal Decoupling Combustion

摘要

The decoupling combustion technology uses the stage transforming method to break the formation coupling chains of various pollutants and to reduce emission of SO_2 and NOx independently at one time. Aiming at developing this technology, this paper investigated S and N transformation in the process of pyrolysis and effect of pyrolysis conditions on product distribution and yields. The experiments were conducted in a small fast-entrained bed under N_2 circumstance. The different kinds of coals were examined under different conditions. The results show that most of coal-S and coal-N are mainly retained in the char, a little released into tar and seldom into gas in relatively low temperature under fast pyrolsis. The similar results were achieved by the experiments of fast pyrolysis in 2.5m high downer circulating fluidized bed. According to the S and N evolution characteristics, this paper proposed two schemes for decoupling combustion technology. The work offers an important reference for decoupling combustion process design.