H_2S is an important product produced by power plant boilers in the process of low NOx combustion. To solve the problems that H_2S may cause various hazards to thermal power plants due to its inflammability

strong corrosion and extreme toxicity

tunable diode laser absorption spectroscopy(TDLAS) method combined with multi-pass cell and computer is employed to build an online measurement system for detecting the molar fraction of low-concentration gas. By using this measurement system

accurate online measurement of H_2S in the mixed gas with the molar fraction of 10–6 magnitude is realized

and the H_2S high-temperature reaction experiment is carried out to explore the influence of experimental temperature and the molar fraction of O_2 in the mixed gas on the reaction. The experimental results show that

under the conditions of pressure of 80 kPa and molar fraction of O_2 ranging from 0 to 5%

the temperature at which H_2S begins to react changes with the molar fraction of O_2. On the whole

the higher the molar fraction of O_2 in the mixed gas

the lower the temperature at which H_2S begins to react. The experimental results can provide some data basis for the generation

transformation and harm control of H_2S in boiler flue gas.