Menetelmä polttoprosessin NOx:n vähentämiseksi

PCT No. PCT/SE90/00516 Sec. 371 Date Jul. 15, 1992 Sec. 102(e) Date Jul. 15, 1992 PCT Filed Aug. 7, 1990 PCT Pub. No. WO91/01793 PCT Pub. Date Feb. 21, 1991.The invention provides a method for reducing the emission of NOx in a pressurized fluidized bed combustion process comprising (a) combusting reaction products in the presence of a sulfur absorbent in a pressurized fluidized bed at a pressure of at least 5 bar to form a flue gas comprising dust particles and an initial concentration of NOx, (b) reacting the NOx in the flue gas with a substance which reduces NOx in a first reaction zone to form a flue gas which has a lower NOx concentration as compared to its initial NOx concentration, wherein the absolute pressure of the flue gas is at least 5 bar and the temperature of the flue gas is at least 450 DEG C. in the first reaction zone, and (c) reducing the NOx concentration in the flue gas provided by step (b) in a second reaction zone by contacting the gas with a solid surface comprised of flue gas dust particles.