Catalytic combustion process and system with wall heat loss control

Claim 1

A process for combusting a nitrogen-containing fuel with resulting low NO x emissions comprising the steps of directing a fuel-rich mixture of the fuel and primary air through at least one fuel-rich combustion zone having a catalytic bed the outer perimeter margin of which is carried by a support structure which comprises a wall, catalytically combusting the mixture within the bed to release thermal energy, limiting transfer of thermal energy from the bed into the support structure to maintain the outer perimeter margin of the bed at an optimum temperature which minimizes formation of NO x during the combustion, the step of limiting transfer of the thermal energy including heating the portion of the wall which is disposed about the first bed to a temperature of greater than 1000° K. during the entire combustion process to minimize the temperature differential between the wall and outer perimeter of the bed and thereby minimize the rate of the heat transfer therebetween, exhausting products of combustion from the bed with such products of combustion being mixed with secondary air and directed through at least one downstream bed comprised of a catalyst material, and catalytically combusting the mixture in the downstream bed to substantially complete combustion of the fuel.