LAUSR

Abstract A framework based on the conventional exergy analysis and expanding exergy analysis is constructed for the sustainability assessment of an energy conversion system. Based on the cumulative exergy consumption and abatement exergy consumption methods, the resource utilization efficiency indicator and the environmental impact factor are defined to evaluate the exergetic sustainability of resource and the environmental sustainability of pollutant throughout the whole life cycle, respectively. Besides, the SJ-type oil shale retorting process is considered as the case study to display the application of the constructed framework. The simulated results are properly consistent with the actual data of the shale oil production process in Yaojie. In the processing capacity of 100 kg/s lump oil shale, 8.15 kg/s shale oil is produced. The total exergetic efficiency (etot) of the study system is 45.16%. The power generation subunit has the largest exergy destruction (49.69 MJ), which accounts for 54.12% of the total exergy destruction in the overall system. Also important from an exergy destruction point of view is the recycle retorting gas burning subunit (19.89 MJ). The power generation subunit has the lowest value of resource utilization efficiency indicator (23.36%) and the largest value of environmental impact factor (43.49%), followed by oil shale retorting, recycle retorting gas burning and semi-coke cooling subunits. Improvement strategies are proposed to improve the sustainability of the whole system.