Combustion and NOx Emission Characteristics of Shenmu Char in a Circulating Fluidized Bed with Post-combustion

Abstract

Combustion and NOx emission characteristics of Shenmu char have been investigated in a circulating fluidized bed test platform composed of a circulating fluidized bed and a post-combustion chamber. The effect of the combustion temperature in the circulating fluidized bed furnace and arrangement of post-combustion air were examined on the post-combustion of Shenmu char. NOx emission is below 100 mg/m3 in all post-combustion experiments. The effect of the temperature in the circulating fluidized bed furnace or post-combustion chamber on NOx emission is not obvious. When the post-combustion air injection position moves upstream, NOx emission decreases. In a reducing atmosphere, most fuel nitrogen is converted to N2. NOx is mainly formed from the reaction of residual N in the char contained in fly ash and O2 from post-combustion air in the post-combustion chamber. Nitrogen in char is gradually released and converted during combustion and not instantaneously.