原位渗透管式气体监测预处理装置的研制及应用

针对现有工业过程气体在线测量预处理方式存在的系统复杂、维护量大、测量延时等问题，基于微孔陶瓷物理特性及空气动力学原理研制了原位渗透管式预处理装置。该预处理装置主要包括光学端和渗透管腔体，当待测气体流经渗透管时，由于绕流作用在来流方向壁面前后形成压差，在压差作用下，气体经过渗透管过滤后进入管内进行激光测量。首先采用CFD数值模拟方法对气体管道和微孔陶瓷渗透管耦合流域进行了流场模拟，发现在单一变量条件下，气体更新速率随着流速和内径的增大而提升，随着外径的增大而降低；然后搭建实验装置进行了实验验证，与流场模拟结果一致；最后进行了原位渗透管式预处理装置研制及现场应用，并采用便携式分析仪进行了对比，发现二者误差<2%。与现有预处理装置相比，渗透管腔体安装于管道内，测量环境与管道工况一致，且取样路径短，可以实现工业过程气体高保真快速在线监测。

DEVELOPMENT AND APPLICATION OF AN IN-SITU PERMEATION TUBE PRETREATMENT DEVICE FOR GAS MONITORING

Aiming at the problems such as complex system, large maintenance and measurement delay in the pretreatment of gas on-line monitoring in industrial process, the in-situ permeation tube pretreatment device is developed based on the physical characteristics of microporous ceramics and aerodynamics principle. The pretreatment device mainly includes two laser emitters and a permeation tube cavity. When the gas flows through the permeation tube, the pressure drop will be formed before and after the wall of the incoming direction, due to the action of flow around. Under the pressure drop, the gas will be filtered through the permeation tube and then enter the tube to be measured by laser. Firstly, the coupling field of pipe and permeation tube are simulated by CFD numerical simulation, and it is shown that under the condition of single variable, the gas renewal rate increases with the increase of flow rate and inner diameter, and decreases with the increase of outer diameter. Then the experimental device is set up for experimental verification, and the result is consistent with the flow field simulation. On this basis, the in-situ permeation tube pretreatment device is developed and applied in the field, and the portable analyzer is used for comparison which show the error between them is less than 2%. Compared with the existing pretreatment devices, the permeation tube cavity is installed in the pipe, the measurement environment is consistent with the working condition, and the sampling path is short, which can realize high fidelity and fast on-line monitoring of industrial process gas.