Invited Talk: Energy Recovery from Food Waste Gasification Process Using Stirling Engine with Heat Harvesting

The high cost of food waste treatment by the traditional method and the hygiene problems caused by the accumulation make the reduction and energy regeneration of food waste locally necessary. In this paper, a combined gasification and CHP unit using Stirling engine system is modeled and evaluated. The process is aimed to treat the food waste from canteen in the campus of Shanghai Jiao Tong University. After pretreatment, the water content of food waste from the canteens at SJTU is less than 17%. By establishing a steady-state chemical reaction equilibrium model, the characteristics and yield of syngas from food waste through gasification process are analyzed. The results show that CO accounts for about 26.9% and H₂ accounts for about 30.3% in syngas, and the low heating value is 6.674 MJ/m³. The syngas is fed to a Stirling engine for power generation. The Stirling engine has low requirements of feedstock and is suitable for distributed waste to energy systems. The electricity efficiency and the whole energy efficiency of the Stirling engine is about 27% and 77%. By handling with food waste 1175kg/d during peak days, the system can generate electricity 1594 kW·h/d and output heat in the form of hot water 2953 kW·h/d.