Syngas tempered pulverized coal reburning: Effect of different reaction gas components

Syngas tempering technology refers to highly reactive gases to consume excess O₂ in the circulating flue gas. An activation environment is created, and the reburning coal is rapidly activated into highly reactive char, increasing its ability to reduce NO. The syngas activation of reburning pulverized coal was studied by a plane flame-carrying flow reactor. Reduced intermediates such as CH_i*, H*, and CO* are produced in the combustion reaction of the main components of the syngas (CH₄, H₂, and CO) with oxygen. The results indicate that after syngas tempering, the char's BET-specific surface area and total pore volume increase by 54.2% and 51.2%, respectively. The relative content of oxygen-containing groups is reduced by almost 5.7%, the relative content of alkyl groups increases by about 14.8%, and the degree of the disorder increases by about 20.68%. The syngas composition has a synergistic tempering effect with O₂. CH₄ has a better tempering effect than H₂, while the effect of CO is not apparent. Among the reducing intermediates, CH_i* has the most significant effect on char, followed by H*. It is instructive to solve the problem that the removal effect of existing pulverized coal reburning to reduce NO_x emissions still needs to be improved.