硝酸熔盐蓄热过程中NO_x的累积排放监测

Monitoring of accumulative NO_x emission in heat storage process of molten nitrate salts

通过实验对太阳能蓄热用硝酸熔盐是否排放NOx以及45#碳钢对这种排放是否存在影响进行研究.参照国家标准固定污染源中氮氧化物测定方法,通过监测不同指定温度下熔盐尾气中氮氧化物的排放量,以评估熔盐蓄热过程是否对环境造成影响.研究结果表明,空气中二元和三元硝酸熔盐在使用温度范围内会排放出少量氮氧化物,但其平均排放浓度远低于国家大气污染综合排放标准的限值.三元硝酸熔盐在相同温度下的平均排放量比二元熔盐的大.熔盐接触45#碳钢后其平均排放量成倍增加,但仍然符合国家大气污染物综合排放标准的要求.

The NOx emission from molten nitrate salts for solar energy heat storage and the influence of 45^# steel plate on this emission amount were experimentally investigated. With reference to the national standard monitoring and determining method of nitrogen oxides in stationary pollution source and by monitoring the emission amount of nitrogen oxides in molten salts tail gas at different temperature, the influence of the heat storage process with molten salts on the environment was assessed. The results showed that binary and ternary molten nitrate salts in the air could emit a small amount of nitrogen oxides at its operational temperature. But its average emission concentration was far lower than the upper limitation of national comprehensive atmospheric pollution discharge standard. The average emissions of ternary molten salts were larger than binary molten salts. After contacting with 45# carbon steel, molten salts would double its average emissions, but was still consistent with national comprehensive atmospheric pollution discharge standard.