新型无毒催化剂在大型燃煤机组上脱硝性能考核试验研究

Experimental study on denitration performance of new non-toxic catalysts on large coal-fired units

火电厂脱硝装置的正常运行对降低大气中氮氧化物有着重要的意义。钒基催化剂因其较高的脱硝效率和较强的抗中毒能力,在工业上被广泛应用。然而,钒氧化物是一种高毒物质,会对环境和人体造成危害,使用过的钒钛催化剂已经明确列入了国家危废名录,因此开发环境友好型催化剂势在必行。稀土元素氧化物,尤其是CeO2具有较强的储氧能力和良好的所化还原能力。稀土金属氧化物催化剂在脱硝领域也有着一定的应用,更重要的是稀土金属氧化物对环境的污染与危害较小,且稀土资源丰富,这使得稀土基催化剂有一定的应用前景。某电厂8号机组脱硝系统催化剂层采用一层新型无毒脱硝催化剂与两层再生钒基催化剂联用的布置形式,以降低催化剂对环境的影响。经过近一年的使用后,在360MW、480MW和600MW三个负荷下进行了脱硝性能考核试验,测试结果表明,单层新型无毒脱硝催化剂的脱硝效率在52%到62%之间,脱硝系统的效率维持在74%到81%之间,系统出口NOx浓度优于超低排放要求,系统氨逃逸量小于保证值2.5μL/L。

The normal operation of denitrification devices in thermal power plants is of great significance for reducing nitrogen oxides in the atmosphere.Vanadium-based catalysts are widely used in industry due to their high denitration efficiency and strong anti-poisoning ability.However,vanadium oxide is a highly toxic substance that causes harm to the environment snf human body.The used vanadium-titanium catalyst has been explicitly listed in the national hazardous waste list,so it is imperative to develop environmentally friendly catalysts.Rare earth element oxides,especially CeO2 have strong oxygen storage capacity and good redox ability.Rare earth metal oxide catalysts also have certain applications in the field of denitrification.More importantly,rare earth metal oxides have less pollution and harm to the environment,and rich in rare earth resources,which makes rare earth-based catalysts have certain application prospects.The catalyst layer of the denitration system of Unit 8 of a power plant uses a new type of non-toxic rare earth denitration catalyst combined with two layers of regenerated vanadium-based catalysts to reduce the environmental impact of the catalyst.After nearly one year of use,the denitration performance test was carried out under three loads of 360MW,480MW and 600MW.The test results show that the denitration efficiency of the single-layer new non-toxic denitration catalyst is between 52%and 62%.The efficiency is maintained between 74%and 81%.The system NOx concentration is better than the ultra-Low emission standard,and the system ammonia slip is less than the guaranteed value of 2.5μL/L.