Integration of direct combustion with gasification for reduction of NOx emissions

A combustion system for causing the combustion of fuel, the combustion of fuel resulting in the generation of post-combustion flue gas, including NOx, the combustion system comprising:

• a primary combustion zone in which the combustion of a main fuel occurs, the combustion of the main fuel generating flue gas, which exit the combustion zone;
• a post-combustion zone for receiving the flue gas;
• and
• a gasifier receiving biomass or waste fuel and producing gaseous product at least in part therefrom and delivering the gaseous product into the post-combustion zone for reacting with the flue gas to reduce NOx emissions, the gaseous product comprising small amounts of alkali-containing compounds, ammonia and other reduced N-containing species, and one or more of the group consisting of carbon monoxide, hydrogen water, and carbon dioxide, the gaseous product being introduced into the post combustion zone under conditions designed to promote reaction of NO with ammonia, other reduced N-containing species and alkali-containing compounds in the presence of one or more of the group comprising syngas components, CO, H2, and hydrocarbons said conditions including at least a temperature of the combustion flue gas at an injection point in the post combustion zone being in the range of 1600-2060° F.