利用氨作为还原剂的选择性非催化还原( SNCR)脱硝技术已得到广泛应用,但其脱硝效率一直比较低,难以满足最新的环保排放要求。通过向烟气中喷射由氨与还原性气体组成的复合还原剂来脱除NOx ,同时运用加入复合还原剂的SNCR基元反应动力学模型对试验过程进行了模拟,结合试验与模拟结果对比不同组分的复合还原剂参与的SNCR脱硝反应特性。结果表明:复合还原剂可有效提高脱硝效率,降低反应的条件温度,拓宽反应的温度窗口。在氨与不同还原性气体组成的复合还原剂中,氨-H2组合可使最佳脱硝温度从920℃下降至750℃;氨-CH4组合与氨-CO组合的效果相近,最佳脱硝温度从920℃下降至840℃左右,但CH4的脱硝温度窗口比CO宽,且相同温度下CH4的最佳脱硝效率比CO最多高出约9%。复合还原剂的最高脱硝效率可达67%左右,采用该项技术可达到最新的NOx 排放标准。
In order to improve the efficiency of selective non-catalytic reduction( SNCR)technology and meet the requirements of the newest environmental protection standard,a compound reducing agent composed of ammonia and reductive gases was injected into flue gas. The ex-perimental process was simulated by SNCR elementary reaction dynamical model which introduced the compound reducing agent. The reaction characteristics were compared by analyzing the experimental results and simulated results. The results showed that,the compound reducing a-gents were able to decrease the required temperature and extend the width of the temperature window significantly. The mixture of ammonia with H2 lowered the optimal reaction temperature from 920 ℃ to 750 ℃,the denitrification effects of the mixture of ammonia with CH4 was similar to that of the mixture of ammonia with CO,both mixture were able to lower the optimum reaction temperature from 920℃ to 840℃. While the temperature window for NOx removal with Ammonia-CH4 as the compound reducing agent was wider than that of CO. Moreover,the denitrification efficiency of ammonia with CH4 was higher than that of ammonia with CO nearly by 9%. The highest denitrification efficiency of compound reducing agent was able to reach around 67%,which met the requirements of the latest NOx emission standards.