Estimation of a Gas Mixture Explosion Risk by Measuring the Oxidation Heat Within a Catalytic Sensor

Combustible gas mixtures and flammable vapors are present in the operating environments of many industries. Detection of the presence of these combustible gases and vapors and assessment of the explosion hazard is of vital importance to ensure that mitigation of the potential hazard can occur before an explosive concentration is reached. In this work, we introduce a gas mixture explosion risk estimation technique for a catalytic sensor. The contribution of this work is threefold. First, we propose the idea of explosion estimation of unknown gas mixtures, which are based on the measurement of heat dissipated during the mixture oxidation at a slow rate. Second, the analysis of transient oxidation processes and sensor response is performed for devising the associated computational scheme to be implemented in a low-power microcontroller. Third, we implement the proposed computational scheme in a wireless sensor node and carry out experiments with various gas mixtures for demonstrating the feasibility of our approach. Combustible heat of gas mixtures of methane, propane, butane, and hydrogen were studied at various concentrations in the range of 28%–56% lower explosive limit. The measurement procedure takes 8.5 s.