GB753084A - Production of formed coke-like solid fuels from finely particulate bituminous coal - Google Patents

Abstract

753,084. Coking processes. KRUPPA, W. J., MACBARCLAY, K., and NOBLES, E. J. May 28, 1954 [May 28, 1953], No. 15904/54. Class 55(1). Coke is obtained from smelting coals of low sulphur and ash content by oxidizing the finely divided coal, forming with a binder a plastic mass which is shaped into elongated pieces and carbonizing the pieces by direct contact with a stream of non-reactive gas at a heating rate of 2À5-5‹C. per minute up to 600‹C. and À75- 1À25‹C, per minute up to the final temperature, e.g. 950‹C. The binder may be coal tar pitch and comprise 12À5-15 per cent of the mass, the moisture content of which may be controlled at 5-8 per cent ; a wetting agent e.g. an alkyl sulphonate may be included, and a small amount of water-soluble binder, e.g. waste sulphite liquor, molasses, starch dextrins may be added to increase the strength throughout the plastic range. Blends with unoxidized coals or additions of anthracite or coke breeze may be made to minimize fractures ; or the binder may be polymerized as by treatment with sulphuric acid. Dried pulverized coal is fed through a pump 2 and suspended in air from a compressor 4 passes through an oxidizer coil 8 in a furnace 9 and thence through a cooler coil 12 to a separator 15 and storage receptacle 16. The coal may be about 10-15 seconds in the oxidizer coil at a temperature of about 675‹-850‹F. From receptacle 16 it passes through a dryer 17 to a mixer 19 in which hot binder with steam preferably at about 325‹F. is sprayed on to it and water may also be added to yield a mix of 5-8 per cent moisture content. This is discharged into an extruder 23 from which a compacted tube of material is forced on to a conveyer 27 and cut up by a knife 26 into lengths and optionally by longitudinal knives, the pieces passing in the embodiment shown through a preheating furnace and heated to about 400‹C. before delivery to a retort. The pieces descend in countercurrent to two gas streams, one of products of the combustion of part of the retort gas and the other of another part fed through a line 36. If the preheater is omitted another stream of retort gas which is preheated may be introduced through a line 40. Tar and pitch are separated from the retort gas, and tar pitch obtained therefrom is employed as binder in the process. Specification 724,774 is referred to.