Predicting bioenergy potential from vinasse digestion: The VUMP Model (Vinasse Utilization for Methane Production)

摘要

Global ethanol production generates 900 to 2000 billion liters per year of a high-strength liquid waste called vinasse. Vinasse represents a substantial renewable energy resource, through anaerobic digestion to produce biogas. Although a variety of previous studies have measured biogas generation from anaerobic treatment of vinasse, no previous study has developed a general model to predict biogas production from anaerobic digestion of vinasse of any composition at a range of temperatures. The aim of this research was thus to build a first-order model VUMP (Vinasse Utilization for Methane Production) to predict methane generation from anaerobic treatment of vinasse from ethanol production, based on readily available inputs of initial vinasse composition and treatment temperature. Lab-scale anaerobic digesters were filled with 4 synthetic vinasse mixtures with differing initial values of chemical oxygen demand, nitrogen, potassium, phosphorous, and sulfur, operated at 3 temperatures each, for a total of 12 reactors. Based on data collected, a multiple linear regression equation (R~2 = 0.80) was developed to predict first-order methane generation rate constant k. The selected best-fit model for k varied positively as functions of temperature, initial chemical oxygen demand, and the product of nitrogen and phosphorous. The model predicted methane generation from commercial vinasse within 20%.