GB747261A - Improvements in or relating to process for reducing the particle size of solid material - Google Patents

Abstract

747,261. Disintegrating apparatus. TEXACO DEVELOPMENT CORPORATION. April 30, 1953 [April 30, 1952], No. 11953/53. Class 59. [Also in Group XII] In a process for reducing the particle size of a solid material, the solid material in granular form is mixed with a vaporizable liquid to form a fluid slurry, the slurry is passed as a confined stream into a heating zone in which all of the liquid is vaporized forming a dispersion of solid particles in the resulting vapour flowing as a confined stream in a highly turbulent flow at a velocity of 500-3000 feet per second whereby the particles of the solid carbonaceous material are shattered by collision. The materials treated are wood and various coals, including anthracite, lignite and bituminous coals and the temperature in the heating zone is such that at least part of the volatizable constituents are distilled from the solid carbonaceous material under treatment. Temperatures of at least 700‹F. are employed and may range upward to about 1200‹F. or higher. In the drawing, coal crushed to a particle size of about # inch in diameter is fed from a hopper 6 and mixed with water from line 7 in a mixer 8. The mixture of coal and water is passed to a thickener 9 where the thickness of the slurry is adjusted, a suitable slurry containing about equal amounts of coal and water. The slurry is then pumped through a heating coil 13 at a velocity at the inlet thereto of at least ¢ foot per second, preferably in excess of 1 foot per second and possibly as high as 100 feet per second. A valve 15 in the form of a plate orifice, venturi or a baffle may be provided in the coil 13 to permit operation of a latter part of the coil at a somewhat lower pressure than the first portion of the coil. The stream of vapours and treated coal is discharged into a separator 18, steam and distilled vapours pass off by line 23, scrubber 26 and line 29 while the solid residue is passed by line 19 into a hopper 21. Condensable distilled constituents are recovered in scrubber 26 and at least a part thereof is drawn off by line 33; water containing these constituents may be supplied to the mixer 8 by line 32. Coarse particles in the separated solids may be recycled to the mixer. Additional stripping of vapours or further distillation of the solids may be effected by contact with a dry gas ; conveniently the dry gas may fluidize a bed of the particles. Or the particles may be briquetted with or without a binder, suitable binders being oil or tar of coal or petroleum origin. In an example, a slurry of lignite was passed in series through four heating coils, each made up of 100 feet of ¢ inch steel pipe. A pressure of 200 lbs. per square inch gauge was maintained in the separator 18 and the temperature at the outlet of the heating coils was 800‹F. The total residence time in the system was about 1 minute. 70 lbs. of carbon di-oxide (forming 88 per cent of the liberated gases) and 80 lbs. of tar were liberated from 1000 lbs. of lignite. The solid product gave test results comparable with better bituminous coals. Specification 683,318 [Group XII] is referred to.