Techno-Economic Assessment of On-Site Production of Biomethane, Bioenergy, and Fertilizer from Small-Scale Anaerobic Digestion of Jabuticaba By-Product

Abstract

Bioenergy recovery from biomass by-products is a promising approach for the circular bioeconomy transition. However, the management of agri-food by-products in stand-alone treatment facilities is a challenge for the low-capacity food processing industry. In this study, the techno-economic assessment of a small-scale anaerobic digestion process was evaluated for the management of jabuticaba by-product and the production of biomethane, electricity, heat, and fertilizer. The process was simulated for a treatment capacity of 782.2 m3 y−1 jabuticaba peel, considering the experimental methane production of 42.31 L CH4 kg−1 TVS. The results of the scaled-up simulated process demonstrated the production of biomethane (13,960.17 m3 y−1), electricity (61.76 MWh y−1), heat (197.62 GJ y−1), and fertilizer (211.47 t y−1). Economic analysis revealed that the process for biomethane recovery from biogas is not profitable, with a net margin of −19.58% and an internal rate of return of −1.77%. However, biogas application in a heat and power unit can improve project feasibility, with a net margin of 33.03%, an internal rate of return of 13.14%, and a payback of 5.03 years. In conclusion, the application of small-scale anaerobic digestion can prevent the wrongful open-air disposal of jabuticaba by-products, with the generation of renewable energy and biofertilizer supporting the green economy toward the transition to a circular economy.

Techno-Economic Assessment of Anaerobic Digestion Technology for Small- and Medium-Sized Animal Husbandry Enterprises

“…The techno-economic assessment of anaerobic digestion facilities, ranging from 50 to 400 kW installed CHP electric power, entailed both capital (CAPEX) and operational (OPEX) expenditures. CAPEX included the engineering, procurement and construction of various components, such as a buffer tank with a mixer and pumps, a digester tank with a mixer, heat exchanger and a membrane gas holder [24][25][26]. Additionally, biogas equipment comprising a scrubber, dryer, and combined heat and power (CHP) unit was accounted for, along with monitoring equipment including liquid and gas flow meters, temperature, pressure and level sensors.…”

Rice straw for energy and value-added products in China: a review

“…The cost of energy and heat production, the cost of biogas purification, and the cost of waste disposal are other issues to consider. The project’s economic advantages must also be examined via the cash gained from the sale of biogas, the value of fertilizers and other by-products produced by the biogas plant, and any possible public subsidies or credits (Sganzerla et al 2023 ). The potential hazards and unpredictability of the project, such as adjustments in substrate supply and energy price variations, must also be evaluated.…”