(350b) Novel System for Small-Scale Gasification of Municipal Solid Waste

Few small-scale waste to energy (WTE) solutions are commercially available. There is a technology gap for systems at the municipal scale and smaller. This need is especially pronounced for deployed military forces, where both waste disposal and energy generation come at a premium. The DoD has invested in development and demonstration of small-scale WTE to help ameliorate this problem. The objective of this project was to develop a battalion-scale (hundreds of persons) WTE system based on gasification. Criteria included one to three tons per day of waste processing, minimal pre-sorting required, and with a net-positive energy balance. A novel, rotary gasification system was conceived to meet these challenges. This system accepts unsorted waste, minimizes process energy through careful heat management and use of hydraulics, and produces power through standard diesel generators. Waste gasification is achieved via an inclined, modified updraft reactor. Evolved syngas is cooled and scrubbed of tars in an oil quench vessel, then an ethylene glycol scrubber. The syngas is introduced into a standard diesel generator, and the energy content of the gas displaces as much as eighty percent of the liquid fuel requirement. Tars and pyrolysis oils that accumulate in the quencher vessel are recycled into the gasifier for further cracking. Testing of the prototype system has demonstrated a net power output of 40kW, inclusive of parasitic losses. Researchers seek to build a containerized unit for long term military demonstration, as well as at a county landfill.