Using methane hydrate to intensify the combustion of low-rank coal fuels

Abstract

Coal mining and processing waste amounts to hundreds of millions of tons annually. Piles of coal refuse pollutes the air with dust and has a risk of self-ignition. However, it can be put to good use as an alternative energy source. To reduce the gas emissions released from its combustion and to increase its integral characteristics, this research suggests co-firing coal mining waste with a gas-vapor mixture formed upon hydrate heating. The corresponding experiments were conducted using a newly developed experimental setup with a boiler unit. The experimental findings were used to obtain an equation for predicting the flame length required for the effective combustion of waste coal. The use of methane hydrate was found to increase the fuel combustion temperature and minimize the unburned carbon. It also provided a significant reduction in the toxic gas emissions (sulfur and nitrogen oxides). A conceptual technological solution has been developed for the co-combustion of gas hydrate with coal and coal mining waste. This technology will help with heating hard-to-reach settlements, producing clean water for population and equipment, as well as recovering slime waste.