Low-cost method for quantification of hydrogen and methane in continuous flow bioreactors

Abstract

Bioreactors of industrial scale for gaseous biofuels constitute a field of research worldwide. Automation at a profitable technical and economic level has not been possible because of fluctuating biological systems. The quantification of biogas in continuous flow is difficult to implement by Gas Chromatography and it is very expensive in account of special sensors. In this work, we developed a system with MQ8 hydrogen and MQ4 methane sensors, used in the detection of industrial leaks, for the determination of gas concentration. The sensors were installed on Arduino cards and programmed to plot the concentration in real time. Calibration curves were made for these sensors making use of a standardized mixture of gases, in hermetic jars of known volume. The result is exponential and reproducible, and when using real biogas samples, no problems of interference with other gases are observed. The prototypes are very low cost with respect to the GC equipment and can be installed at the gas outlet of bioreactors with a mechatronic system that allows the monitoring of the composition in real time, which will allow to obtain microbial kinetics in semi-continuous flow in a very economical way.