Coal Disintegration Using High Pressure Water Jet

2 Research method Different methods of coal processing into fuel [1, 6, 12] usually require its intensive comminution. Such situation needs the creation of new technologies for coal micronization [4, 11, 17] that enlarge specific surface of coal micro particles what finally intensifies burning process of such coal dust. Some interesting effects of water-coal mixture ensure waterjetting technology implementation [3, 19]. Such technology enables the production of fuel from powdered coal in water slurry [2, 3, 5] or in energetic fluids (methanol or low viscosity oils) [3, 14]. Traditional mechanical grinders are used for coal grid comminution by means of coal particles crushing and grinding. However such grinders' usage for coal micronization is economically unprofitable because of their low efficiency [6, 10]. It is a result of the coal being much more resistant to pressing stresses than to stretching ones [7, 13, 15]. Taking the above into consideration an alternative technology involving high-pressure water jet can be implemented. Such a jet striking coal surface penetrates inside causing stretching stresses and such water wedge effect leads to easy disintegration of such coal particle. It should be admitted here that hard coal structure is characterized by many cracks [16, 18] and that is the reason why such material is especially susceptible to disintegration during hydrojetting grinding.