The objective of this project was to develop a battalion-scale waste-to-energy (WTE) system based on the principle of gasification. More specifically, the goal the WTE system was to convert 1 to 3 tons per day of mixed wastes to energy, with minimal pre-processing, and with a net-positive energy output (net of parasitic losses). Also, the size of the system was to be limited to two, 20-ft shipping containers.
The research team took the approach of developing an entire working prototype, rather than analyzing a portion of the waste gasification process. The rotary kiln WTE system was conceived to address the Statement of Need (SON) criteria, with the following design principles:
- accept and process mixed, unsorted municipal waste materials
- minimize process energy required through careful heat management and use of hydraulics
- integrate into contingency utility systems by using standard diesel generators.
The main gasification reactor is a novel design, based on an updraft gasifier, but rotating with new techniques for introducing waste, and removing syngas. This system was tested on multiple waste mixtures, representative of reported, in-theater waste composition.
The rotary gasification system was successfully developed and tested. The syngas produced was energy rich, mirroring commercial liquid fuels in composition. The resulting ash test non-hazardous for heavy metals. Perhaps most importantly, researchers showed that waste could be consumed with a net-positive energy output.
If this technology were to be further developed, demonstrated, and fielded, it could solve the problem of contingency waste disposal, eliminating burn pits, or the need for hauling outside the perimeter of the camp. Additionally, this system outputs net-positive energy, tens of kilowatts at the target scale, thereby displacing a modest fuel requirement.