Syngas production from thermochemical conversion of mixed food waste: A review

Abstract

Lately, the generation of leftover food or cooked food waste has turned out to be a critical issue and its disposal in an environmental friendly way has been a challenge. This food waste is being sent for incineration and landfilling which results in a significant contribution to environmental pollution. Therefore, alternative methods for processing food waste in an environmentally benign way have been explored by many researchers. Thermochemical methods are one of those methods and are found to be promising for not only handling the food waste in an ecological way but also producing renewable energy efficiently in the form of bio‐oil and syngas along with a solid byproduct, that is, biochar. However, the generation of syngas is favored by only two thermochemical processes, fast pyrolysis, and gasification. Some derived processes such as co‐pyrolysis, and co‐gasification can also generate syngas. All these processes for syngas generation differ from each other in terms of process conditions (temperature, reaction agents, and residence time) and syngas quality generated (amount of syngas produced, syngas composition, and heating capacity). Additionally, supercritical water gasification is the latest process developed for processing food waste to generate syngas with much higher hydrogen fraction; however, it produces syngas with less yield and involves high operational costs.