Renewable Energy Resources and Technologies
Ali Nazari; Morteza Hosseinpour; Mahdi Rezaei
Abstract
In this study, the impact of digestate treatment after Anaerobic Digestion (AD) process in two scenarios is analyzed in the case of an industrial diary unit in the United States. The first scenario involves production of liquid fertilizer and compost, while the second scenario lacks such a treatment ...
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In this study, the impact of digestate treatment after Anaerobic Digestion (AD) process in two scenarios is analyzed in the case of an industrial diary unit in the United States. The first scenario involves production of liquid fertilizer and compost, while the second scenario lacks such a treatment process. Aspen Plus is used to simulate the AD process and evaluate the general properties of biogas and digestate. The results of technical analysis show insignificant changes in the net power production from the CHP unit in Scenario 1. The economic analysis, however, indicates the necessity of digestate treatment for AD systems to be profitable. Furthermore, the results of environmental analysis indicate the mitigation of about 93.4 kilotonnes of greenhouse gas (GHG) emissions in Scenario 1, while AD in Scenario 2 saves only 12 kilotonnes of GHG emissions. In other words, digestate treatment has a more significant environmental impact than the power production and its profitability from CHP unit. The reason could be attributed to the enormous consumption of energy during the production of chemical fertilizers where the digestate treatment process (scenario 1) offsets the utilization of chemical fertilizers in the agriculture industry.
