International Journal of Research and Innovation in Applied Science (IJRIAS) |Volume VIII, Issue II, February 2023|ISSN 2454-6194
Experimental and Full-scale Plant Assessment of Biogas Production via Anaerobic Co-digestion
Abdulkadir M. Zabi1, Abdulfatai A. Adisa2, Umar A. Aji3, Vincent C. Ntichika4, Madu D. Gadzama5, Ebube P. Nwadiokwu6
1Department of Energy Systems Engineering, Cyprus International University, Nicosia, Cyprus
2,4 Department of Chemical Engineering, University of Lagos Nigeria
3Department of Science Technology, Waziri Umaru Federal Polytechnic, Birnin Kebbi, Nigeria
5,6Dangote Fertili1ser Company, Nigeria
Received: 02 November 2022; Revised: 05 January 2023; Accepted: 07 January 2023; Published: 03 March 2023
Abstract – Biogas production from anaerobic digestion of organic waste is an important renewable energy source with great potential of replacing fossil fuels for heat and electricity generation. However, efficient anaerobic digestion process and energy conversion technology must be ensured for better biogas yield and energy generation. The present study involves experimental assessment of biogas production from anaerobic co-digestion of biomass feedstock. The experimental stage involves the co-digestion of livestock manure with slaughterhouse waste and vegetable waste, different sets of experiments were conducted at mesophilic condition of 37o C, 25 days of retention time and utilizing water displacement experimental setup. The biogas yields obtained for the co-digestion of Cow dung + Poultry manure (S1), Cow dung + Sheep manure (S2), Slaughterhouse waste + Poultry manure (S3), Sheep dung + Poultry manure (S4), Poultry manure + Whey (S5) and Vegetable waste + Cow (S6) are 0.0236m3/kg, 0.0231m3/kg, 0.0264m3/kg, 0.0234m3/kg, 0.0266m3/kg and 0.0191m3/kg respectively. These values are acceptable values of biogas yields for livestock manure co-digestion. However the co-digestion revealed that the biogas yields obtained are slightly above the minimum reported value for co-digestion of manure slurry, this is due to the nature of the experimental setup used. According to the simulation conducted with engineering equation solver software on the modeled biogas plant, energy efficiency of 42.55% was achieved by integrating the digestion process to the steam cycle which provides better heat utilization.
Keywords: -Biogas, Biomass, Anaerobic Co-digestion, Livestock manure, Slaughterhouse waste, Vegetable waste, Whey and Energy Efficiency.
I. Introduction
Energy generation and consumption has been a major issue globally for decades, about 80% of the total world’s energy generation is from the fossils fuels. Environmental and economic problems associated with the utilization of fossil fuels has make it paramount for each country to search for an alternative source of energy other than the fossil based. The Kyoto protocol and the Paris agreement signed by many countries for the global preservation have shown improvement in many countries in the utilization of the renewable energy sources [1]. These sources are produce naturally and do not have any environment effect upon utilizing, they include solar energy, wind energy, hydro and biomass. Solar, hydro and
wind energy are suitable in certain region of the world and their generation is intermittent with the need. Biomass has great advantage over all renewable sources because of its availability everywhere in the world and round clock generation [2]. Municipal solid waste, agricultural feeds, industrial waste, agricultural waste, sewage sludge, livestock manure etc. are termed as biomass. In the advanced countries large amount of waste are generated due to population and poor recycle, this is a great threat to the wellbeing of both humans and animals. Different energy conversion techniques have developed for the conversion of each biomass to a useful energy. Municipal solids wastes are majorly incineration, pyrolysis and gasification process by generating thermal energy and subsequently electricity using the steam or gas cycles. Livestock manures, sewage sludge and agricultural residues undergo anaerobic digestion process to generate a clean gas called biogas which when properly process can be used in place of natural gas mechanical systems [3]. Anaerobic digestion of biomass is a bio chemical process that involves the conversion of organic feeds waste like livestock manure, agricultural waste, food waste etc to biogas through fermentation process. This fermentation is performed in the absence of oxygen by different bacteria in stages. The process leads to the formation of biogas which primarily consists of methane (CH4) and carbon dioxide (CO2) other are like hydrogen sulphide and ammonia gasses are found in traces [4]. Biogas constitutes 50 – 70% methane, 30 – 50% carbon dioxide and small traces of other gases like hydrogen sulphide and ammonia. This gas can be utilized for the production of power in a large scale, for vehicles and also domestic heat source. Biogas if upgraded to 90% methane and compressed can be in internal combustion engines in place of natural gas [5].