Microbial Co-processing and Beneficiation of Low-rank Coals for Clean Fuel Production: A Review
Abstract
Coal is a non-renewable fossil fuel combusted to generate power or used to produce liquid or gas fuels with high energy densities. The abundance of coal reserves and the dependence of many countries on coal as a cheap energy resource are the basis for the predicted expansion in coal consumption in the future. However, at the global level, there is a growing concern about the role of coal combustion in environmental pollution, global warming, and climate change. Consequently, it becomes imperative to consider and adopt novel technologies aimed at bridging the gap between demand and supply. These technologies must meet core eligibility criteria and demonstrate substan-tial benefits, including reduced adverse environmental impacts, improved utilization safety, and decreased gas emissions. This review aims at addressing these issues by means of microbial activi-ties and/or microbial biomass. Firstly, combining low-rank coal and microbial biomass would al-low for safe and effective coal utilization through different co-processing technologies to make valuable fuel products. Secondly, microorganisms associated with sulfur removal and dust sup-pression activities may facilitate "clean" coal production, promoting environmental impact reduc-tion. Furthermore, biogenic coal-to-methane conversion by methanogenic microorganisms is an effective approach to generating high-quality gas. The literature reviewed here demonstrates that these technologies hold great potential for sustainably coping with ever-growing energy demand.
