Decrease of energy demand for bioethanol-based polygeneration system through case study

Economic competitiveness of bioethanol production strongly depends on the amount of heat and power consumed during the production process. Integration of different energy conversion processes by polygeneration is one of the solutions to minimize the use of energy resources to best meet user's energy demands. In this study, a biogas generation system, a Fuel Cell system and a green house are integrated in the bioethanol plant to form a polygeneration system. At the same time, in order to further reduce the consumption of external energy sources, possibilities of heat energy integration, which looks for the best utilization of energy flows generated or consumed inside the process, have been investigated. Simulation of the polygeneration system is carried out by Simulink; energy saving potential for the polygeneration plant is analyzed to find the optimum configuration to maximize the electricity production while producing sufficient heat from both the Fuel Cell unit and pellets combustion to satisfy the energy requirements of the whole plant. Based on the simulation results, detailed energy and mass flow processes of the whole polygeneration plant was presented.