Design And Development Of On-line Detection System For Concentration Field Of Flue Gas In Beiler

The effective detection of the combustion state inside the furnace of a power station is an important measure to realize the optimization control of combustion,increase the combustion efficiency and reduce the emission of pollutants.Tunable semiconductor laser absorption spectroscopy is a new type of optical non-contact gas detection technology developed rapidly in recent years.It has the characteristics of high sensitivity,fast response,strong anti-interference ability and so on,with great adaptability at combustion space real-time measurement of gas parameters under such harsh conditions.In view of the complicated and changeable combustion conditions inside the furnace of the boiler in the power plant and the large space of the actual measurement environment,the absorption data of the light path based on the intensive arrangement is required to obtain the better reconstruction result of the gas concentration field distribution.However,in the existing TDLAS gas detection system Lasers and detectors often use a fixed arrangement,limiting the number of optical paths,resulting in insufficient data to effectively absorb,seriously affecting the quality of the image reconstruction of the concentration distribution,it is difficult to popularize the application.In order to solve the above problems,this paper combines the mechanical transmission mechanism to realize the automatic scanning and receiving of laser signal.By rotating the single laser beam at the four light sources,four groups of measuring optical paths are arranged in fan shape.Eight laser signals including 80 laser signals The field parameter measurement system effectively breaks through the limitations of the traditional arrangement for the laser light path measurement and reduces the overall cost of the measurement system.In order to fully simulate the scene of the power plant measurement conditions,we set up a large analog boiler station furnace simulation in the laboratory by referencing the four corners of the power plant tangentially fired boiler and scaling down the its size,then realize the simulation of the distribution of the gas concentration field in the combustion process inside the furnace through the control of the furnace interior vacuum conditions and gas source device.According to the data measured by the measuring system on the test bench,the two-dimensional distribution of the C02 gas concentration field is reconstructed using the concentration inversion reconstruction program based on the algebraic iterative reconstruction algorithm(ART).A series of repeated experiments were carried out for the measurement of gas with different concentrations and distribution forms.The experimental results were compared with the experimental gas concentrations of the standard mixtures and the error analysis showed that the reconstruction results could reflect the gas concentration in the boiler hearth The two-dimensional distribution of the state accurately and provide important data support for achieving optimal combustion control.