A METHOD OF REMOVING NITROGEN FROM HOT FLUE GASES

摘要

A method of removing nitrogen from hot flue gases In the device for selective non-catalytic reduction of nitrogen oxides, a liquid nitrogen-containing reducing agent is sprayed through two-component lances into a stream of hot flue gases. Spraying occurs in pulsatory operation at a frequency of 5 to 70 per second, preferably 10 to 20 per second. As a result of this mode of operation, a spray cone of relatively coarse long-range drops and a spray cone of relatively fine short-range drops are produced alternately at each two-component nozzle. The reducing agent is ammonia dissolved in water (ammonia solution) at flue-gas temperatures of 1060.degree.C to 1170.degree.C. The device for working the method comprises a flue-gas duct 3 incorporating a number of twocomponent lances 4 operated by a pressure medium. The liquid and gas feed pipes for each two-component nozzle lance 4 are connected to a first resonance chamber 15 disposed in the twocomponent nozzle and upstream of at least one additional resonance chamber 18 separated from the first resonance chamber 15 by a restrictor 17. The last resonance chamber 18, considered in the direction of flow, is then directly connected to the outlet opening 19 of the two-component nozzle. (Fig. 1)