Abstract: A method and a system for injection of a solution of a compound into a gas at elevated temperature. The method includes the steps of injecting the solution into an injection channel being provided into at least a portion of an outer channel and being surrounded by and spaced apart from the outer channel, passing the gas along space between inner wall of the outer channel and outer wall of the injection channel and along inner space of the injection channel, evaporating the solution in and on inner wall of the injection channel, and decomposing the compound in and on the inner wall of the injection channel and in the gas. The solution can be aqueous solution comprising urea or ammonia, the gas is an exhaust gas from combustion, and the injection channel is a cylindrical channel concentrically installed in the outer channel.

Abstract: Method and apparatus for uniformly injecting a fluid stream into a gas stream at elevated temperature by means of an injection nozzle comprising a nozzle head and a supply inner tube being concentrically surrounded with an outer casing tube spaced apart from the inner supply tube. It comprises passing the fluid stream through the inner tube and the nozzle head and maintaining temperature of the fluid stream in the inner tube by providing thermal insulation in at least part of an annular space between the inner tube and the outer tube. Further it comprises maintaining a constant flow of the fluid inside the inner tube and nozzle head by plugging the nozzle head at outlet end and spraying the fluid stream through a number of nozzle holes provided in the nozzle head adjacent to the outlet end of the nozzle head.