应用自适应滤波的天然气中H_(2)S浓度反演系统  

H2S concentration inversion system in natural gas based on adaptive filtering

作　　者：李国林[1] 吴赟辉 张泽成 张雪娜[1] 邢兰昌[1] LI Guolin;WU Yunhui;ZHANG Zecheng;ZHANG Xuena;XING Lanchang(College of Information and Control Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)控制科学与工程学院,山东青岛266580

出　　处：《实验技术与管理》2022年第8期65-71,145,共8页Experimental Technology and Management

基　　金：国家重点研发计划项目(2020YFB0408402);中国石油大学(华东)校级青年教改项目(QN-202016);中央高校科研项目(19CX02045A);山东省重点研发项目(2019GHY112084)。

摘　　要：在石油化工生产过程中,天然气中硫化氢(HS)气体存在一定的泄露风险。由于HS具有腐蚀性和剧毒特性,严重危害人身的生命健康安全,因此对天然气中H_(2)S气体进行痕量检测具有重要意义。基于可调谐二极管激光吸收光谱技术(TDLAS)和波长调制技术(WMS),选取H_(2)S气体在1590.6 nm的近红外光谱作为目标吸收峰,采用中心波长为1590 nm的分布式反馈(DFB)激光器(SN:16110883)、光程为20 m的Herriot气室和响应范围为800~1700 nm的In GaAs探测器,利用经典最小二乘(CLS)算法反演气体浓度,利用LMS(least mean square)自适应滤波器代替传统带通滤波器,对输入到数字正交锁相放大器的信号做预处理,开展天然气中HS气体的痕量检测实验研究。实验结果表明:天然气中HS浓度反演系统的检测下限可达1μmol/mol;经3h的稳定性测试,当积分时间为134 s时,其检测极限可达到89 nmol/mol;最后开展抗干扰性实验,当作为背景气体的甲烷(CH_(4))和二氧化碳(CO_(2))分别从0~100μmol/mol和100~0μmol/mol变化时,HS气体测量误差最大仅为0.42μmol/mol。因此将LMS自适应滤波器应用到数字正交锁相放大器的前端作为预处理单元,改善了天然气中HS浓度反演系统的信噪比,提高了系统的稳定性与鲁棒性。Hydrogen sulfide gas(HS) in natural gas has a certain risk of leakage in the process of petrochemical production. Because HS sulfide is corrosive and highly toxic, it seriously endangers human life and health safety.Therefore, it is of great significance for trace detection of HS sulfide in natural gas. Based on tunable diode laser absorption spectroscopy(TDLAS) and wavelength modulation(WMS), the near-infrared spectrum of HS sulfide gas at 1590.6 nm is selected as the target absorption peak. A distributed feedback(DFB) laser(SN:16110883) with a central wavelength of 1590 nm, a Herriot gas chamber with an optical path of 20 m and an InGaAs detector with a response range of 800-1700 nm are used to retrieve the gas concentration using the classical least squares(CLS)algorithm. The LMS(Least Mean Square) adaptive filter is used to replace the traditional bandpass filter, and the signal input to the digital orthogonal phase-locked amplifier is preprocessed to carry out the trace detection of HS sulfide gas in natural gas. The results show that the detection limit of HS sulfide concentration inversion system in natural gas can reach 1 μmol/mol. When the integral time is 134 s, the theoretical detection limit can reach 89 nmol/mol after 3 hours of stability test. Finally, the anti-interference experiment is carried out. When methane(CH4) and carbon dioxide(CO2) as background gas changed from 0-100 μmol/mol and 100-0 μmol/mol respectively, the maximum measurement error of HS sulfide gas is only 0.42 μmol/mol. Therefore, the LMS adaptive filter is applied to the front end of the digital orthogonal phase-locked amplifier as a pretreatment unit,which improves the SNR of the HS concentration inversion system in natural gas, and improves the stability and robustness of the system.

关 键 词：LMS自适应滤波器 数字正交锁相放大器 硫化氢检测 可调谐二极管激光吸收光谱技术 

分 类 号：O433.1[机械工程—光学工程]