Thermodynamic and economic analysis of a novel coupled system based on low carbon biomass utilization

In order to reduce the environmental impact of conventional sludge treatment methods and to utilize the energy in sludge more efficiently, this paper proposes a coupled system based on a sewage sludge gasifier (SSG), a solid oxide fuel cell (SOFC), a supercritical carbon dioxide cycle (S-CO2) and an organic Rankine cycle (ORC). The coupled system is simulated and modeled by Aspen Plus software, while the results of each subsystem simulation are validated against literature results. In order to understand the performance of the system, the performance of the project was analyzed thermodynamically and economically. It was found that the net power output of the proposed system is 37.34 MW with a net efficiency of 61.4S% and exergy efficiency of 55.62%. The main source of exergy destruction is the two components, gasifier and SOFC, which account for 62.45% of the total exergy destruction. The construction investment of the proposed system will be recovered in only 6.13 years and the project will have a net present value of US ${\$}$17,723.82 thousand over a 20-year lifetime. The conclusions indicate the advantages and benefits of the project in terms of sludge waste utilization.