SCR (Selective Catalytic Reduction) is a selective catalytic reduction technology, which has developed rapidly in recent years and has been widely used in Western Europe and Japan. At present, catalytic reduction of ammonia is the most widely used technology. It has the advantages of no by-products, no secondary pollution, simple equipment structure, high removal efficiency (up to over 90%), reliable operation and convenient maintenance. Selectivity means that NH3 preferentially reacts with nitrogen oxides in the presence of oxygen under the action of catalyst to generate nitrogen and water, but does not react with oxygen in flue gas. The main reaction formula is: 4NO+4NH3+O2 → 4N2+6H2O (1) 2NO2+4NH3+O2 → 3N2+6H2O (2) In the absence of catalyst, the above chemical reaction only occurs in a very narrow temperature range (about 980℃). When the catalyst is used, the reaction temperature can be controlled at 300-400℃, which is equivalent to the flue gas temperature between the boiler economizer and the air preheater. The above reaction is exothermic, and the temperature rise of the catalyst caused by the reaction can be ignored because of the low concentration of nitrogen oxides in the flue gas. /feed/d 0 1373 f 082025 aafcc 6 c 466 e 1a5a 3 162024 f 1a 72 . JPEG @ f _ auto？ token = 1b 8908277578 de 6b 23 de 6892 b 15d 306 1