An innovative renewable energy-based tri-generation system for electricity, LNG regasification and hydrogen production

Waste incineration is a potent technique, that deals with the waste generated in a sustainable way to properly manage and reduce the generated waste and produce useful energy simultaneously. However, the waste-toelectrical efficiency of incineration plants is less (20-22) % because of the high moisture content of waste and flue gas heat losses. In the present study, a tri-generation system consisting of a solar parabolic trough collector integrated with a waste-to-energy plant, a liquefied natural gas (LNG), and a hydrogen production system is proposed and thermodynamically investigated. Parabolic trough collectors serve as a secondary heating source to the steam coming out of the incineration boiler. The useful heat collected by the parabolic trough solar field is provided to the fluid exiting the incineration boiler and entering into the steam turbine to improve the steam condition, while LNG is vaporized by the energy of exhaust flue gas and produces power for the PEM electrolyzer. Waste-to-energy incineration facility is capable of operating with a feed rate of 350 tons/day, producing 6.3 MW of power at an inlet temperature of 400 degrees C of the turbine. However, the net power produced is increased to 7.72 MW with increase in turbine inlet temperature to 515 degrees C. Results of the study conclude that the energetic and the exergetic efficiencies of the incineration plant are found to be 27.93 % and 26.51 %, respectively. In addition, both the first and second law efficiencies are observed as 21.51 % and 25.74 %, respectively, while the rate of hydrogen production is 7.72 kg/h. The cumulative exergy destruction rate of the system is 29.3 MW and the WtE boiler shares the maximum portion (58.14 %) of the exergy destruction.