煤层气发电高温NO_x烟气SCR处理技术及其应用

煤层气发电是煤层气利用的重要途径之一,但煤层气发电排放的高温尾气中含有大量的氮氧化物(NO_x),会对环境造成污染,需要对其进行脱硝处理,而高温烟气(约500℃)又不宜用V_2O_5/TiO_2蜂窝式催化剂进行直接脱硝处理。为此,在分析比较煤层气发电高温烟气与燃煤发电烟气差别的基础上,应用纳米组装和灌注法研制了GJ-HC-5型催化剂,并通过室内实验确定了脱除NO_x的最佳温度窗口(400~600℃)。之后,在某煤层气电厂进行中间试验,将发电机组高温烟气直接通入到SCR一体化装置进行脱硝处理,在SCR反应器进出口处连续监测,进口NO_x浓度约为620 mg/m~3,出口监测浓度约为20 mg/m~3,对烟气中的NO_x的脱除率始终保持在90%以上。试验结果表明,所研制的高温SCR催化剂符合实际烟气温度条件,且制备方法简单,是一种可行的煤层气发电高温烟气的脱硝方法。

Research and application of a Selective Catalytic Reduction (SCR) Unit for high temperature NOx exhaust gas from CBM power plants

A CBM power plant is one of the most important ways to utilize CBM, but the exhaust gas from CBM power generation containing a large amount of NO_x can cause pollution to the environment, so denitrification is necessary. Because of the high temperature (about 500 ℃) of the exhaust gas, the V₂O₅/TiO₂ cellular catalyst commonly suitable for a coal-fired power plant denitrification can't be used in a CBM power plant. Therefore, on the basis of analyzing the differences between high-temperature exhaust gas from CBM power plants and that from coal power plants, GJ-HC-5 catalyst was developed by nano-fabrication and perfusion methods, and its best temperature range (400-600 ℃) for the NO_x removal was found out by lab experiments. In the intermediate test in a CBM power plant, the concentration of NO_x monitored continuously dropped from 620 mg/m³ at the inlet of the SCR reactor to 20 mg/m³ at the outlet, indicating a NO_x removal rate of over 90%. The experiment results show that the developed high-temperature SCR catalyst, suitable for the exhaust gas temperature and simple in preparation, is a feasible method to remove NO_x from high-temperature exhaust gas of CBM power plants.