Assessment of biogas and syngas production from sugarcane vinasse: A sustainable alternative for the production of renewable fuels

The increasing demand for renewable energy sources as a substitute for fossil fuels has driven researchers to develop sustainable processes for biomass energy reuse in biofuel production. Based on this premise, the present study aimed to simulate the production process of synthesis gas (syngas) from vinasse, a by-product of the sugar and alcohol industry, highlighting the applicability of this gas in transitioning toward a more renewable and sustainable energy future. The simulation was conducted in four distinct stages using the Aspen HYSYS (R) software. The first stage involved obtaining hydrated ethanol from sugarcane juice, followed by anaerobic digestion of vinasse to produce biogas. The third stage involved purifying the biogas to obtain biomethane. Finally, the simulation of steam methane reforming was performed to generate syngas. The modeling and simulation results demonstrated the feasibility of the process, as it generated 20.68 Nm(3) of biogas (similar to 55% vol CH4 and 45% vol CO2) per 1 Nm(3) of vinasse, corresponding to 11.66 Nm(3) of biomethane (similar to 96.5% mol CH4), which aligns with national regulatory standards and the literature presented. Regarding syngas, both evaluated configurations yielded satisfactory results. The first configuration resulted in syngas with an H-2/CO molar ratio of three, making it a viable source of pure hydrogen and a raw material for biofuel production, such as dimethyl ether and methanol. The second configuration, with an H-2/CO molar ratio of two, holds great potential for its application in the synthesis of liquid fuels (Fischer-Tropsch), serving as a direct substitute for gasoline, diesel, and jet fuel.