总有机碳分析仪信号处理算法的分析

研制基于高温燃烧氧化-非分散红外吸收法测定水中总有机碳(TOC)的分析仪.叙述仪器的核心器件和工作流程,并对影响检测结果的红外检测算法进行分析.实验结果表明:利用快速傅里叶变换对测量信号进行曲线平滑降噪的效果较好,取平滑处理后的曲线峰高作为二氧化碳浓度测量值能够消除气体流速不稳对测量结果的影响;TOC分析仪测量时间小于5 min,同时满足实验室测量和在线监测的时间要求,并具有较低的成本.

Total Organic Carbon Analyzer and Detection Algorithm

A total organic carbon analyzer using high temperature catalytic oxidation technique and non-dispersive infrared absorption method according to Lambert-Beer law is developed. Essential components and workflow are described. The infrared detection algorithm that has influence on detection results is analyzed. The experimental results prove that the noise of the measured signal caused by gas flow rate instability can be eliminated using fast Fourier transform. Carbon dioxide concentration can be measured by finding the peak height of the smoothed curve. The measurement time of the low-cost TOC analyzer is less than 5 minutes, so it can be used as laboratory instrument and on-line monitoring equipment.