Simulation of Anaerobic Co-Digestion Process for the Biogas Production using ASPEN PLUS

The modern energy trends call for the transfer of energy requirements for sustainable industrial growth from conventional fuels to renewable energy sources. The rapid depletion of the fossil fuels and their hazards to the environment are of great concern for maintaining modern lifestyles and ensuring the safer environment. There lies a great interest for scientists for exploiting the potential for renewable and carbon-neutral sources of energy. Biomass in its different forms like agricultural waste residue, animal manure, and wastewater has a great perspective for utilization as a source for thermal heat or power generation. Anaerobic digestion (AD) which is a biochemical route of converting biomass into a biogas has high possibility to contribute in this context. Biogas is methane (CH4) dominant fuel which can perhaps replace the natural gas. However, to increase the calorific value of biogas its CO2 content needs to be decreased. There are several processes to upgrade the biogas by increasing the CH4 content. This is sometimes not possible with a single substrate. Hence an evolving technology known as anaerobic co-digestion (AcoD) is adopted for increasing the CH4 percentage composition in biogas. This study presents the simulated AcoD reactor for three substrates for producing the biogas. The various substrates modeled were date seed waste, date palm leaf waste, coffee waste, wastewater, and animal manure. A simulation of the whole system will be conducted using ASPEN PLUS software by simulating the Anaerobic Digester using different biomass and feedstock ratios to find the optimum ratio that maximizes the methane in biogas produced. The best biomass for maximum methane production is a dates tree leaf, but its CO2 emission is higher than the rest. The biomass date seed waste using as feedstock provided the highest CH4/CO2 ratio of 2.3.