Dimensionamento energético de um biodigestor industrial para produção de biogás

Abstract

This work presents the energetic design of a vertical biodigester used for biogas production, based on detailed modeling of the mass and energy balances of its thermal system. The study determines the thermal power required by the reactor, the global heat transfer coefficient (UA) of the tubular heat exchanger TRC-002/003, and the effective capacity of the equipment to meet the process heating demand. By integrating the exchanger and reactor balances, the minimum operating conditions of the hot-water circuit and the recirculated digestate are evaluated to maintain the mesophilic temperature of the system. The work also compares different heat-supply alternatives — including engine waste-heat recovery, solar energy, and electric resistance — through a techno-economic assessment based on CAPEX, OPEX, net present value (NPV), internal rate of return (IRR), and payback time. The results support the optimization of heating systems and decision-making in industrial biodigester projects, contributing to higher energetic efficiency and improved economic feasibility within the Brazilian biogas sector.