Profitability of biogas production as a source of energy for tequila distilleries from the anaerobic treatment of tequila vinasses

Resumen

Objective: To analyze the profitability of biogas production from tequila vinasses in an anaerobic packed bed reactor (PBR) plant to use biogas as substitute of heavy fuel (fuel oil) in boilers of the tequila industry.
Design/methodology/approach: Financial information for biogas production was gathered; the methodology with the approach of investment project evaluation was used for two reactor volumes, 7 m3 and 10 m3, and the profitability was determined through the following financial indicators: Net Present Value (NPV), Internal Rate of Return (IRR), Benefit-Cost Ratio (B/C R).
Results: Biogas production is profitable starting from a reactor’s volume of 7 m³ and it is more favorable when the process is scaled to 10 m³. It was obtained for a volume of 7 m³ and 10 m³ at an updating rate of 12% (NPV $780 376.70 and $5 062 685.22), (B/C R $1.04 and $1.21), (IRR 14% and 26%).
Limitations on study/implications: The results are based on values reached in a PBR plant at laboratory scale with a capacity of 445 L, assuming that the values of yield and removal of the chemical demand for oxygen (CDO) are not modified when scaling the process to 7 m³ and 10 m³.
Findings/conclusions: Analysis of the results showed that the use of tequila vinasses to generate renewable
energy for auto-consumption in an anaerobic PBR plant is profitable.