Patent ID: 6863005
Filing Date: 2005-03-08
Classification: B01D

Abstract:
1. A method to decrease emission of mercury, comprising: selecting a factor to control a combustion process to generate a flue gas comprising fly ash with enhanced in situ-formed unburned carbon, wherein the factor is selected from the group consisting of reburning fuel, flue gas temperature, OFA injection, coal particle size, LNB flow, LNB design, combustion zone air, stoichiometric ratio of fuel, fuel/air mixing in a primary combustion zone and fuel/air mixing in a secondary combustion zone; controlling the combustion process according to the factor to produce the flue gas comprising fly ash with enhanced unburned carbon and to vaporize mercury; allowing the flue gas to cool to collect fly ash with enhanced unburned carbon with obsorbed mercury; passing the fly ash with enhanced unburned carbon with absorbed mercury through an ash burnout unit to remove carbon from the fly ash and to produce a mercury-containing exhaust gas; and passing the mercury-containing exhaust gas through a mercury capture reactor to capture the mercury.