Patent ID: 7597864
Filing Date: 2009-10-06
Classification: B01D,F23J,F23M

Abstract:
1. A method of removing mercury from flue gas produced by combustion devices burning mercury containing fuel, the flue gas containing particles and passing from a combustion zone in which the temperature exceeds 2600° F., through a first temperature zone in which the temperatures range from 1750° F. to 2100° F., through a second temperature zone in which the temperatures range from 900° F. to 1450° F. and through a particle removal device, the method comprising: introducing ammonia into the flue gas when the flue gas passes through the second temperature zone, the ammonia being introduced in sufficient amounts to oxidize mercury within the flue gas; thereafter passing the flue gas through a reaction zone stabilizer, the reaction zone stabilizer positioned within the furnace at a location where the flue gas has passed the at least one injector and the flue gas is at a temperature in the range of from 900° F. to 1450° F.; thereafter rapidly cooling the flue gas after the ammonia has been introduced into the flue gas from a temperature within the range of 1,450° F. to 900° F. to a temperature below 900° F. at a rate of at least 1000° F. per second to minimize decomposition of mercury chloride in the flue gas; directing the flue gas to the particle removal device; and monitoring the flue gas after the flue has passed through the particle removal device to determine whether mercury vapor is present within a desired range and thereby confirm that ammonia has been introduced in sufficient amounts to oxidize mercury within the flue gas.