This paper presents a correlative method for the cost-efficient measurement of the energy content of propanated biomethane, which is relevant for injection into gas distribution grids. The gross calorific value and Wobbe index were predicted by the regression models from the measured set of physical properties of the gas sample, including speed of sound, sound attenuation parameter, and carbon dioxide concentration. The required properties can be measured using standard sensors and instruments; therefore, they enable in situ application of the method. The results of the experimental validation corroborated with the results of chromatographic analysis.
Keywords calorific value, ultrasonic measurement, speed of sound, non-dispersive infrared absorption