Rapid Determination of Different Nitrogen Oxides in the Outlet Gas from the Iron Ore Sintering Process by Means of Infra-red Spectroscopy

点击翻译按钮获取中文摘要

A new method quantitatively determining a small amount of nitrogen oxide species and other gases take a part in the formation of nitrogen oxides were developed. This method can be applicable to the conditions, where the concentrations of gaseous species are quite low and they change rapidly. The principle of the measurement is an application of Fourier Transform Infra-red Spectroscopy (FTIR). The determination limit and response for 90% are 0.5ppm, respectively. It becomes possible due to rapid elimination of water vapor which gives wide range of infra-red absorption bands by the multi-pipe made of molecule-exchange film and due to limitation of measured absorption peaks of objective gases which are not influenced by residual water vapor, carbon-dioxide, methene and so forth.The major feature of the developed method is as follows :1) Software for determination of gaseous concentration : Optimum algorithm for high-speed calculation and record of spectra data considering proper range of absorption corresponding to objective gases.2) Gas cell with a small volume and optical length : Gas cell having inner volume 100cc and optical path 10m was applied. Gas flow condition in the gas cell was optimized by the mathematical simulation.3) Application to modeled and combustion gases : Calibration curve was prepared using various standard gas mixtured and then it was applied to actual combustion gases. The results gives the validity of the method.