The increase of CO and H_2S volume fraction leads to severe high-temperature corrosion of water wall of pulverized coal boiler under low nitrogen concentration combustion condition.Therefore

it is of great significance to monitor the volume fraction of CO and H_2S on near-wall surface in real time and establish an early warning model for high-temperature corrosion based on the measured data.In this work

the tunable diode laser absorption(TDLAS) technology was used to measure the volume fraction of CO and H_2S near the boiler water wall.Firstly

Herriot multiple reflection cell was used to improve the measurement accuracy and reduce the detection limit.Then the dynamic measurement of CO/H_2S volume fraction was carried out to verify the proposed experimental approach.Preliminary results showed that the measured CO and H_2S volume fractions agree very well with the preset values in the range of 0 to 2 000μL/L and 0 to 20μL/L respectively with high measurement accuracy.Finally

combined with the high-fidelity pretreatment technology of flue gas based on the principle of constant-flow dilution

the developed CO/H_2S monitoring device was applied to the field of pulverized coal boiler in large thermal power units.The alternating measurement strategy was applied to realize synchronous on-line monitoring of CO/H_2S in both “reducing zone” and “burnout zone” of boiler furnace.Based on the monitoring date

the boiler combustion was further adjusted to slow down the high-temperature corrosion rate of the water wall while ensuring ultra-low emission from flue gas.Eventually

the efficient

environmentally friendly

safe and intelligent operation of thermal power unit was realized.