Patent ID: 6895875

Claim:
A method to reduce mercury in gas emissions from the combustion of coal in a combustion unit said method comprising: a. combusting coal in a primary combustion zone of the combustion unit under conditions of low or no excess oxygen during combustion in the zone wherein the excess oxygen in the combustion zone is no greater than two percent (2%); b. generating carbon rich fly ash during combustion and entraining the fly ash into flue as generated by the combustion; c. releasing mercury during the combustion into the flue gases; d. staging combustion air by injecting combustion air in a post-combustion zone downstream of the combustion zone in the combustion unit; e. injecting coal into a reburn zone in the post-combustion zone and upstream of an overfire air burnout zone; f. adsorbing the mercury in the flue gas with the fly ash; g. collecting the fly ash with the adsorbed mercury in a combustion waste treatment system.