燃煤电厂超低排放颗粒物在线监测烟气除湿技术

燃煤电厂超低排放颗粒物浓度在线监测常采用光散射法，但该法受排放烟气的相对湿度、水滴和汽雾等影响。为提高测试结果的准确性，以HJ836—2017《固定污染源废气、低浓度颗粒物的测定 重量法》为参照标准，通过实验找出了光散射法测量误差与相对湿度的关系；为降低待测烟气相对温度及水滴和汽雾，对旋流加热器和直管加热器进行了研究。实验结果表明：相对湿度＜55%时，颗粒物浓度的测量误差可忽略不计；在相同功耗条件下，旋流加热器的加热效率比直管加热器的加热效率高30%；为满足燃煤电厂超低排放要求，提高颗粒物在线监测的可靠性，烟气预处理采用旋流加热时的温度不应低于120 ℃。

Flue Gas Dehumidification Technology for On-line Monitoring of Ultra-Low Emission Particulate Matter in Coal-Fired Power Plants

Light scattering method is often used in the on-line monitoring of ultra-low emission particle concentration in coal-fired power plants, but its accuracy may be affected by the relative humidity, water droplets, vapor mist and so on. In this paper, the relationship between the measurement error of light scattering method and the relative humidity was found out through the experiment with HJ836-2017 "weight method for the determination of waste gas and low concentration particulate matter of fixed pollution source" as the reference standard. In order to reduce the relative temperature, water droplets and vapor mist of the flue gas to be measured, the application of swirl heater and straight tube heater were explored. The experimental results show that: when the relative humidity is less than 55%, the measurement error of particle concentration can be ignored; under the same power consumption, the heating efficiency of swirl heater is 30% higher than that of straight tube heater; in order to meet the ultra-low emission requirements of coal-fired power plant and improve the reliability of on-line monitoring of particles, the temperature of swirl heating used in flue gas pretreatment should be kept no lower than 120 ℃.