溴甲烷质量浓度检测系统的设计及试验研究

Design and experimental study of methyl bromide mass concentration measuring system

针对熏蒸处理中检测溴甲烷质量浓度时,基于单个通用型热导式传感器TCS208F检测结果易受容器内温度、相对湿度及CO_2条件干扰的问题,设计研发了溴甲烷质量浓度检测系统,系统包括热导式传感器TCS208F、数字化温湿度传感器和红外CO_2传感器,采用多元线性回归方法研究了容器内温度、相对湿度、CO_2及溴甲烷对TCS208F模块输出电压的影响,建立了溴甲烷质量浓度估计值与TCS208F模块输出电压、温度、相对湿度及CO_2体积分数检测结果之间关系的数学模型。试验结果表明:使用该溴甲烷质量浓度检测系统检测溴甲烷质量浓度时,系统将自动采集容器内温度、相对湿度、CO_2及TCS208F模块输出电压值,经数学模型处理后系统所得的溴甲烷质量浓度估计值与经安捷伦网络气相色谱仪6890N的检测结果偏差不超过1.1g/m3。在检验检疫口岸熏蒸处理中使用该检测系统检测溴甲烷质量浓度具有实用性。

During quarantine treatment, the methyl bromide （MB） mass concentration measurement based on thermal conductivity sensor TCS208F only is easily affected by temperature, relative humidity （RH） and CO2 inside sealed chamber. A MB mass concentration measuring system was developed. The system includes thermal conductivity sensor TCS208F,digital temperature ＆ humidity sensor and CO2 sensor. The effects of temperature, RH, CO2 and MB on TCS208F module output voltage were studied based on multiple linear regression analysis. A mathematical model was proposed to estimate the MB mass concentration based on the measurement results of TCS208F module output voltage, temperature,RH and CO2 volume fraction. When the system was used for measuring MB mass concentration, the estimate results based on embedded mathematical model show that deviations between estimations and measurements from Agilent GC6890N were no more than 1. 1 g/m^3. The measuring system can deliver usefulness during MB mass concentration measuring process in fumigation treatment at the entry-exit port.