| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for removing nitrogen oxide which is suitable for purifying exhaust gas of an automobile at a relatively low temperature wherein in a method for removing nitrogen oxides in combustion exhaust gas by a catalytic reduction process by means of ammonia gas, a high pressure ammonia storage tank is not used, and as the generation of decomposed ammo nia gas due to decomposition of urea, high temperature heating or hydrolytic catalysts are not used to vaporize urea and a relatively low temperature can be used. SOLUTION: As an ammonia generating reducing agent, at least any one of the group consisting of ammonium carbamate, ammonium carbonate, and ammonium hydrogencarbonate is heated and decomposed to generate a mixed gas of ammonia and carbon dioxide, which are mixed with a combustion exhaust gas to remove nitrogen oxides by a catalytic reduction reaction, following which a part of the exhaust gas is used as a heating source for generation of decomposed ammonia of a reducing agent. |
