Using methane hydrate to intensify the combustion of composite slurry fuels

Abstract

Combustion of composite slurry fuels based on industrial and municipal waste is an effective way to both recover the said waste and address the problem of fossil fuel depletion. The flexible composition of such fuels can be adjusted to include raw materials available in any specific region of the world. Another benefit they provide is the opportunity to recover waste in different proportions to conventional fuels. There is, however, a problem of long ignition delay times of composite slurry fuels, especially if they contain a significant proportion of water or high-moisture wastes. Here we suggest intensifying their ignition by involving methane released from gas hydrates. Gas hydrates contain a large amount of water that reduces the concentrations of sulfur, nitrogen, and carbon oxides in flue gases. The experimental findings have shown that the involvement of gas hydrate reduces the ignition delay time of a coal-water slurry droplet by more than four times. Adding gas hydrate also contributes to higher combustion temperature and degree of fuel combustion. On the basis of the results obtained, we propose a coal-water slurry/gas hydrate co-combustion system for energy production facilities.