Cavitation based pretreatment of biomass for intensification of biogas production

Abstract

Biogas, a clean and renewable form of energy, could very well substitute for conventional sources of energy (fossil fuels, oil, etc.) which are causing environmental problems. The present work investigates the application of hydrodynamic cavitation (HC) for the pretreatment of biomass with the objective of enhancing biogas production. Effect of different parameters viz.rice straw to water ratio (0.5%, 1%, 2%, 3%, and 4%), operating pressure (1-3 bar), and also treatment time (10-30 min) have been investigated using an orifice plate as a cavitating device. The water displacement method is used for the analysis of the quantity of biogas formation. As we increased the biomass ratio is increased from 0.5 to 3% with the same treatment time 15 min biogas yield also increased from 52 to 345 mL respectively. Combining chemical treatment with hydrodynamic cavitation it has been observed that it gives a maximum (470 mL) of biogas yield as compared to HC alone (360 mL) for the same biomass ratio of 4%. Overall, it has been established that a significant enhancement in the biogas production can be obtained due to the pretreatment using HC which can also be further intensified by combination with chemical treatment.