Patent ID: 8470277

Claim:
A process for reducing the concentration of nitrogen oxides in combustion gases produced by a combustor operating with variations in load, by an SCR reactor effective for utilizing gasified urea, the process comprising: determining the concentration of NO x in the combustion gases, determining a required total gas flow necessary to supply the SCR reactor with NO x reducing and carrier gases from an injection grid to reduce NO x in the combustion gases to a predetermined level, feeding aqueous urea and gasification gases to a thermal urea gasification reactor in an amounts sufficient to produce a NO x -reducing gas stream comprising urea gasification products in amounts sufficient to reduce NO x in the combustion gases, mixing the NO x -reducing gas stream comprising urea gasification products with a stream of carrier gases to provide a grid supply gas stream, and feeding the grid supply gas stream to an injection grid, the process further including the step of determining the temperature of the gasification gases fed to the thermal urea gasification reactor and the temperature of the stream of carrier gases.