Simulation and multi-objective assessment of an environmentally friendly trigeneration system powered by biogas from landfilling using a novel cascade heat integration model

This study introduces a novel integrated trigeneration system fed by biogas fuel from landfilling, promoting environmentally sustainable practices. In the system proposed within this study, fuel combustion occurs through the implementation of a gas turbine cycle, while the subsequent waste heat is efficiently recuperated within a cascade framework. The combustion process is combined with a supercritical carbon dioxide cycle, an organic Rankine cycle, an ammonia Rankine cycle, a seawater desalination unit, and a Kalina cycle. The process is simulated using the Aspen HYSYS software while conducting a comprehensive analysis encompassing the energy, exergy, economic, and environmental aspects. In view of the thermodynamic perspective, the analysis yields values of 70.28%, 24.89%, and 57.51% for the energy utilization factor, and thermal and exergy efficiencies, respectively. The subsequent environmental results illustrate that the proposed scheme exhibits a carbon dioxide emission level of 0.272 kgCO2/kWh, yielding a noteworthy reduction of 51.02% in carbon dioxide emissions compared to a traditional power and heat generation system. Besides, the economic analysis demonstrates a positive net present value of 779, 571, 045 $ for the proposed process. Furthermore, the total unit cost of products and cost of energy are found at 12.25 $/GJ and 0.022 $/kWh, respectively.