The Development Of TDLAS Gas Detection Instrument And The Study On Algorithms

Today’s society, gas detection technology, which has penetrated into the coal,metallurgy, electric power and other industrial production industries as well asmedical, environmental protection and other social fields successfully, has became animportant safeguard for the sustainable development of industry, agriculture andenvironmental. With the deepening of research and theory, various industries aremaking more and higher requirements for gas detection technology. Common gasdetection technologies have some defects in many facets, such as the operationprocess, environmental suitability, rapid detection capabilities, online analysiscapabilities, gas detection accuracy and remote sensing control, and can’t adapt to therapid development trend. In this paper, a tunable diode laser absorption spectroscopy(TDLAS) technology combines all the above properties, is gradually gainingawareness and adoption.This paper details the formation mechanism of absorption spectra and proposesthe spectral selection method principles by basing on the characteristics of differentgases absorption spectrum in near-infrared region, develops an universal gas detectionequipment successfully. The instrument is based on the theory by TDLAS technology,combines with reflecting pool and harmonic detection technology to achieve a varietygas of real-time monitoring, concentration data storage and display, hardware systemfeedback control, system automatically linearity correction and other functions.What’s more, the instrument is lightweight and flexible, simple to operate, whichprovide a solid technical foundation for the gas detection applications.Recognizing that the inherent interference of the system has been unable to makeimprovements through increasing hardware performance, this paper applies dataprocessing techniques and presents wavelet transform algorithm to achieve thede-noising and baseline correction in TDLAS gas detection system. Showing as theexperiments, this method is high efficient and well effective, provides an practicalsolution for the special environment which is unable to achieve the reference lightpath background subtraction.There are multi-objective factors in the selection of the absorption lines,therefore, the selected lines of some gases can’t avoid the interference of adjacent peaks. To solve this problem, this paper proposes a mathematical analysis ofdifferential exhumation algorithm, which is a method to squeeze the shape of theabsorption peaks by ortho-subtraction and shift superposition. This method is a goodsolution to the problem of spectral overlap interference, and raises the portion of thegas concentration measurement accuracy effectively.