Real‐Time Sensing Technology of Mixed Gas Concentrations Using Multiple Micromachined Thermal Conductivity Detectors

ABSTRACT This paper presents a new method for fast simultaneous monitoring of individual gas concentrations in a gas mixture by using small micromachined sensors. The developed method uses output data from multiple micromachined thermal conductivity detectors of different sensitivities. We confirmed that the fabricated sensors can accurately determine the concentrations of each of three gases in a mixture. The prototype sensor module was miniaturized to less than 1/72th the size of conventional gas chromatography (GC) equipment. Demonstration tests were conducted in a CO 2 electrolysis cell for CO 2 capture and utilization technologies, and each gas concentration was successfully monitored 176 times faster than conventional GC could for a mixture of H 2 , CO 2 , and CO gases.