ENVIRONMENTAL IMPACT ASSESSMENT ON FUEL GAS PRODUCTION FROM DISTILLER'S GRAINS BY ANAEROBIC DIGESTION COUPLED WITH GASIFICATION
As an efficient conversion pathway to produce biomass fuel gas,the integrated anaerobic digestion and gasification process shows significant advantages in energy conversion.To ascertain the effect of anaerobic digestion degree on the environmental benefits,a model of gradient-controlled anaerobic digestion and gasification integration process was built,and the distiller's grains were treated with different anaerobic digestion times.The life cycle analysis method and Gabi software were used to conduct the environmental impact assessment.Results showed that the energy produced by the gradient-controlled coupled system can not only cover the drying of the biogas residue,but also achieve net energy output.And the positive environmental impacts based on energy flow can offset the negative environmental impacts based on material flow,so that the system can obtain positive comprehensive environmental impacts.The optimal total potential environmental impact of a 1000 kg distiller's grains system was-2.02×10-9 with anaerobic digestion treatment lasting for 8 days.The control of the coupling degree of anaerobic digestion and gasification process makes the coupled system optimize its net energy output and have the most favorable environmental impact,so as to provide theoretical guidance for the application of the coupled process.
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