滤膜形变对β射线衰减法颗粒物质量浓度监测结果准确性的影响及修正

Effect and Correction of Filter Membrane Deformation on Particles Concentration Measurement of β-ray Attenuation Method

为解决固定污染源颗粒物排放连续监测过程中单一光散射法因仪器漂移和光学窗口易污染等而造成的频繁人工标定问题,实现光散射与β射线衰减联用法的颗粒物质量浓度连续在线监测系统的自动标定技术,通过研究负压作用下滤膜形变对β射线衰减法颗粒物质量浓度监测结果准确性的影响,在提出厚度影响因子的计算方法基础上完成了对原颗粒物质量浓度计算公式的修正。实验结果表明,与标准称重法相比,修正后的平均相对误差由原来的8%下降为3%,在相关性系数达到0. 988的同时,截距从4. 935 4降低为1. 012 7,进一步提高了β射线衰减法在低浓度环境下的测量精度。

In order to solve the problem of frequent manual calibration during the continuous monitoring of the emission of particulate matter from fixed pollution sources,which caused by single light scattering method due to instrument drift and easy pollution of optical window,and to realize automatic calibration technology of continuous emission monitoring system on mass concentration of particulate matter combined with light scattering andβ-ray attenuation,the effect of filter membrane deformation under negative pressure on the accuracy of monitoring results mass concentration of particulate byβ-ray attenuation method was studied,on the basis of the calculation method of thickness influence factor,the correction of the calculation formula of original particle mass concentration was completed.The experiment shows that,compared with the standard weighting method,the average relative error of the revised formula decreases from 8%to 3%,while the correlation coefficient reaches to 0.988,the intercept decreases from 4.935 4 to 1.012 7,which further improves the accuracy of theβ-ray attenuation method for monitoring particle concentration in low concentration environment.