Research on etalon‐free CO₂ measurement based on direct absorption signal fitting

AbstractThe emission of carbon dioxide (CO2) by thermal power plants is the main factor leading to the greenhouse effect. The measurement of CO2 is of great significance to carbon emission data statistics. In this paper, a measurement system based on tunable diode laser absorption spectroscopy (TDLAS) was built to measure the spectrum of CO2 near 1579 nm. To simplify the experimental system, a direct absorption signal fitting method is proposed to replace etalons for time‐frequency conversion. The method was applied to the measurement of four different concentrations of CO2 in the range of 7%–16%, and the measurement results were compared with the multipeak method, another etalon‐free method. The results show that the mean relative error of the measurement results is 4.23%, which is 1.76% lower than the measurement results of the multipeak method. The experimental research provides a feasible idea to simplify the CO2 measurement system based on TDLAS.