GB275602A - - Google Patents

Abstract

275,602. Wisner, C. B. Aug. 7, 1926, [Convention date]. Coking processes.-Coal is distilled in a two stage process, the first stage consisting in heating the coal with access of air to retain a sufficient hydrocarbon content to allow the charge to take the form of balls, and the second stage consisting of carbonizing the resultant mass at a temperature sufficient only to remove condensible hydrocarbons. The fuel is ground to pass a screen having three-eights inch openings and is subjected in a rotary retort for from 15 to 45 minutes to heating just below the temperature at which hydrocarbon vapours are evolved while air, which may be preheated, is passed over the fuel, oneeighth of a cubic foot to five cubic feet of air per pound of fuel being employed. The preheated fuel is then heated from 750‹ to 900' F. until it has a volatile content of about 12 per cent, and during its passage through a second rotary retort is rolled into balls of varying sizes having the properties required for domestic and steam fuel purposes. A strongly coking coal may be mixed with a non-coking coal, or pitch may be used as a binder. A suitable apparatus comprises two rotary retorts 1, 1<1> mounted on rollers 6, 6<1> and heated by a furnace 12 provided with gas burners 12<1> the hot gases passing by a flue 14 to the annular space 4<1> between the cylinders 2<1>, 3<1> of the lower retort and from the latter by a pipe 15 into the annular space 4 of retort 1, returning by a pipe 16 to a reheating flue 17 in the furnace. A bye-pass 18 is arranged to control the temperature of the upper retort. The fuel is supplied from a hopper 21 and after being preheated in retort 1 is passed by a conduit 22<1> into carbonizing retort 1<1> from which it is discharged by pipe 22" into hoppers 24. Pipes 27 lead from the forward ends of the retorts to dust collectors 28 from which vapours are removed through pipes 29. Specification 217,554 is referred to.