Optical Design And Realization Of Distributed Laser Gas Measurement And Analysis System

In order to prevent air pollution,protect public health,promote ecological civilization construction,China in August 29,2015 revised the "People’s Republic of China Air Pollution Prevention Law".Adhere to the source of governance,to strengthen the coal,steel industry and other air pollution prevention and control.As we all know,Iron and steel smelting process will produce a lot of process gases,Among them,carbon monoxide(CO)gas is used in the blast furnace blast furnace coke,in the temperature below 570 ℃,the occurrence of the reduction reaction generated.Carbon monoxide(CO)harmful to humans,inhalation will lead to human tissue organs hypoxia,endangering people’s health,and mixed with the air,prone to explosion,threatening people’s lives.Therefore,in the steel industry,the detection and monitoring of carbon monoxide concentration is conducive to industrial process control,improve the quality of production and security personnel life safety.Indeed,the detection and monitoring of iron and steel smelting process produces a lot of process gases,inseparable from the advanced and effective new principles of gas detection and new technology.This article relies on the relevant scientific research project-Chongqing science and technology research project(project number: 2012920130332): Distributed laser gas detection key technology research.Based on the key technology of optical design in tunable semiconductor laser absorption spectroscopy,the optical design and experimental study of distributed laser gas measurement and analysis system were carried out.The carbon monoxide(CO)gas was produced in the process of iron and steel metallurgy industry.Based on the research of distributed laser gas analysis technology,the characteristic absorption peaks of carbon monoxide(CO)gas at 2330 nm were determined.In the collimation system,when the single lens structure is used,the beam divergence angle is poor,and the system structure is complicated and the volume is large.The ABCD law in the optical design is used to study the transmission characteristics of the Gaussian beam.Out of a single lens on the laser beam can not have a good collimation effect of the conclusion.In order to improve the detection sensitivity of the gas detection in the laser gas analysis and measurement system,the key technical problems that will cause the light collimation to decrease and affect the quality of the image quality.In order to establish the theoretical model of the three-component expansion system,The optical parameters of the distributed fiber bundle system are deduced.Considering the difficulty of installing and debugging the structure of the expansion system in the engineering application,the optical design method of the multi-fold expansion structure is studied in order to facilitate the subsequent docking debugging of the beam bundle structure and enhance the adaptability of the detection system.Based on the optical simulation software ZEMAX,the initial design and optimization of the collimated and multiples of the distributed fiber system are completed.The results show that,according to the optical design to establish the program and its parameters,the optical fiber output wavelength of 2330 nm point light source alignment.At the same time,respectively,to achieve the purpose of expanding the ratio of 4-7,access to the diameter of 20,25,30,35 mm parallel light,the beam shot good results,good quality,to meet the project research required for distributed laser gas Analysis of design requirements for optical beam propagation in measurement and measurement system.In addition,based on the optical simulation software ZEMAX,this paper has carried on the comparative analysis of the double-split and aspherical lens structures in the fixed-group part of the three-component expanded structure.The advantages and disadvantages of the two kinds of structural methods and the application of the field.In the gas detection test,the second harmonic signal is used to calculate the concentration of carbon monoxide.In the fitting work,one-time fitting and quadratic fitting are used,and the two methods are analyzed and compared,and the method is applied to the distributed laser gas The optical design goal of the measurement and analysis system.