Design of Auto Mix Single Stage Anaerobic Digester and Aspen Plus Simulation for Biogas Production

Abstract

Bio fuels have been considered to be the viable alternatives and the supportive sources for the depleting fossil fuels under the objective of satisfying the energy demand. The work explored the possibility of biogas production in various operational scales. The present work can be categorized into two parts. In the first part, the work has surveyed various digester designs under operation and focused on the mixing and intermittent aeration that are not under light in the regular practice. The digester gas collector configuration that could promote the mixing and intermittent aeration was designed. The setup was run on 20 L scale with an objective of observing the gas production phenomenon. The recommended operational solutions were modified and implemented in the form of a 50 L digester setup to observe the performance improvements in attaining self-buffering capacity and sensitivity to the acidic feed stocks. Further suggested modifications lead to the final design that could promote intermittent aeration and mix the digester constituents without the use of impeller and with minimal or no power consumption depending on the amount of gas produced. An advanced design called compartmental digester design was next presented for the medium to large scale applications which was run on 200 L scale in a semi continuous mode using cow dung as substrate and was tested for the feasibility. The second part of our work focused on simulation of a two stage anaerobic digester configuration for studying the kinetics of hydrolysis, acidogenesis and acetogenesis and methanogenesis in three different reactors. In this study, kitchen waste stream were analysed for biogas production which was compared with the results of NISARGRUNA biogas plant (BARC) for the validation of the model and the model with same kinetics was then used to analyse the gas production from poultry manure