典型煤种O_2/CO_2/H_2O气氛下中高温燃烧时NO的生成特性

NO Emission Characteristics of Typical Coals Under O_2/CO_2/H_2O Atmosphere at Intermediate and High Temperatures

利用自制恒温热分析系统研究了大同烟煤和阳泉无烟煤在O_2/CO_2/H_2O气氛下中高温燃烧时NO的释放行为,并与O_2/N_2和O_2/CO_2气氛下的情况进行了对比分析.结果表明:当氧气体积分数为5%时,大同烟煤在O_2/CO_2和O_2/N_2气氛下燃烧时只有一个NO体积分数峰,而在O_2/CO_2/H_2O气氛下却变成一前一后2个峰;当氧气体积分数升高到21%后,大同烟煤在O_2/CO_2/H_2O气氛中的NO释放过程又变为一个体积分数峰;阳泉无烟煤的NO释放过程与大同烟煤类似;大同烟煤在O_2/CO_2气氛中的NO排放量始终低于O_2/N_2气氛中;由于低氧气体积分数下H_2O气化反应的影响,大同烟煤在O_2/CO_2/H_2O气氛中的NO排放量在高温下高于O_2/CO_2气氛中;氧气体积分数升高后,大同烟煤在O_2/CO_2/H_2O气氛中的NO排放量又低于O_2/CO_2气氛中;阳泉无烟煤的NO排放量高于大同烟煤,但其不同气氛下的变化趋势与大同烟煤一致.

NO emission characteristics of Datong bituminous coal （DT） and Yangquan anthracite （YQ） under O2/H2O/CO2 atmosphere at intermediate and high temperatures were investigated in an isothermal thermal analysis system, and the experimental results were subsequently compared with those under O2/ N2 and O2/CO2 atmospheres. Results indicate that there is an obvious peak in the NO release curve of DT under O2/N2 and O2/CO2 atmospheres at 5% oxygen concentration, but the only NO peak turns into two separated ones under O2/CO2/H2O atmosphere. However, when the oxygen concentration gets up to 21% , the two separated peaks turn back into one peak under O2/CO2/H2O atmosphere. The NO release profiles of YQ are similar to those of DT. The NO emission of DT in O2/CO2 is always lower than that in O2/N2. At high temperatures, the NO emission of DT in O2/CO2/H2O is higher than that in O2/CO2 due to H2O gasification at low oxygen concentrations. But as the oxygen concentration increases, the NO emission of DT in O2/CO2/H2O becomes lower compared to that in O2/CO2. The NO emission of YQ is higher than that of DT, but the changing trend is similar to that of DT under different atmospheres.