Abstract: Apparatus and a method of comminuting coal to about 1 to 10 microns size comprising introducing the coal particles into a plurality of vessels, each of which is subjected to high pressure, superheated steam which infuses into the pores of said particles equalizing the pressure therein with that surrounding the particles in the vessel. By opening a discharge valve of each vessel connected to a nozzle leading into a housing, in which a paddle wheel is located, the particles will burst in each vessel to smaller size because of the reduction of the pressure therein surrounding the particles. Opening of said valve will effect acceleration, turbulence and collision of the particles to cause further breakage particularly as the particles are further expanded through the nozzle and against the blades of the paddle wheel driven in a direction opposite that of the nozzle jets. The vessel may be operated under partial vacuum by connection to a steam condenser through which cooling water flows.

Abstract: Apparatus and a method of comminuting coal to about 1 to 10 microns size comprising introducing the coal particles into a plurality of vessels, each of which is subjected to high pressure, superheated steam which infuses into the pores of said particles equalizing the pressure therein with that surrounding the particles in the vessel. By opening a discharge valve of each vessel connected to a nozzle leading into a housing, in which a paddle wheel is located, the particles will burst in each vessel to smaller size because of the reduction of the pressure therein surrounding the particles. Opening of said valve will effect acceleration, turbulence and collision of the particles to cause further breakage particularly as the particles are further expanded through the nozzle and against the blades of the paddle wheel driven in a direction opposite that of the nozzle jets. The vessel may be operated under partial vacuum by connection to a steam condenser through which cooling water flows.