Abstract: An injection lance for injecting a homogeneous mixture of steam/ammonia gas into a furnace having a flue gas (combustion) stream moving therethrough to reduce nitrogen oxides therein. The lance includes an outer and an inner tube. The outer end of the inner tube is in communication with the outer tube while the outer end of the outer tube is in communication with a source of homogeneous steam/ammonia. The outer end of the inner tube sealably embraces the exterior surface of the lance feed tube so that the homogeneous steam/ammonia mixture being introduced into the outer tube passes towards the inner end of the lance between the annulus formed by the concentric outer and inner tubes. The homogeneous steam/ammonia mixture is passed into the annular space in the inner tube and then is discharged from the lance through discharge flow control nozzles or ports which extend from the interior of the inner tube to the exterior of the outer tube.