Patent GB-1457353-A (GB)
Title: Coal treating method and apparatus for coke plants
IPC: C10B57/08
Filed: 1974-04-16
Abstract: 1457353 Coking pulverized coal WAAGNERBIRO AG 16 April 1974 [13 April 1973] 16637/74 Heading C5E [Also in Division F4] A coke plant is operated by feeding pulverized coal into a coal dryer, directing a hot drying gas upwardly through the coal dryer and suspending the pulverized coal in the gas to form a fluidized bed, delivering the dry heated coal to a coal preheater wherein the coal is heated by exposure to a heating gas, and then in a dry preheated condition to a coke oven, the drying gas and the heating gas being of different condition or composition. The coal may be dried further by contact with coils in the fluidized bed through which a drying fluid is circulated. The drying gas, drying fluid and heating gas are heated directly or indirectly by heat extracted from discharged hot coke, e.g. by circulating a dry-quenching gas along a closed path through the hot coke and heating the drying gas and fluid by the dry-quenching gas. The heating gas which may be an inert gas such as carbon dioxide, nitrogen or a mixture thereof, or the drying fluid in the form of steam, is circulated along a closed path which intersects in heat-exchanging relationship the closed path of the dry-quenching gas. The drying fluid when in the form of a liquid may be placed in heat-exchanging relationship with a further fluid heated directly by the dry quenching gas. Just prior to delivery of the dry preheated coal to a coke oven, the coal is temporarily stored for a short time in a bin to which part of the inert heating gas is delivered to prevent explosions at the bin and for maintaining the coal at an elevated temperature. Part of the dry-quenching gas may be diverted from the closed path and utilized as the heating gas, and after being exposed to the dry coal at the heater, is returned to the closed path for recirculation with the remainder of the dryquenching gas through the hot coke. A coke plant includes coal-dryer means for drying pulverized coal, heating means communicating with the coal-dryer means for receiving dry coal therefrom and for heating the dry coal, a bunker for receiving hot coke from a coke oven, heat-transfer means communicating with the bunker, the coal-dryer means and the heating means, for extracting heat from hot coke in the bunker and for delivering the extracted heat in part to the coal dryer means for drying the coal in a fluidized bed at least in part with the extracted heat, and in part to the heating means for heating the dry coal, and transporting means communicating with the heating means for transporting coal in hot, dry condition to a coke battery, so that the coal is received at the coke battery in a dry, preheated condition. The heat transfer means includes means for circulating a dry-quenching gas along a closed path through the bunker to extract heat from hot coke therein, means including coils situated in the coal drying means for at least partly drying coal by contact between the latter and the coils and providing a closed path for a coal-drying fluid, and means for circulating a heating gas through the heating means to heat dry coal therein, the heat-transfer means further including a part of heat-exchanger means one of which provides transfer of heat from the quenching gas circulating means to the drying fluid circulating means and the other of which provides transfer of heat from the quenching gas circulating means to the heating gas circulating means. One heat exchanger means is situated subsequent to the other heat exchanger means in the path of flow of the dry-quenching gas from the bunker out of the latter and back to the bunker so that the other heat exchanging means cools the dry-quenching gas before the one-heat exchanging means extracts heat therefrom. The coal-drying means includes a container in which is located means for directing upwardly a hot gas to maintain a fluidized bed of pulverized coal which is dried by the hot gas and the coils. The hot gas directing means may include an additional heat exchanger situated along the closed path of the dry-quenching gas for extracting further heat therefrom, e.g. in the path of flow of the quenching gas out of the bunker and back thereto subsequent to the other heat exchangers only after heat has been extracted for the heating gas and drying fluid. The transporting means includes a bin in which the dry, preheated coke is temporarily stored prior to being charged into the coke ovens of a coke battery, and a branch conduit communicating with the bin and the heating-gas circulating means for directing a part of the heating gas to the bin. Specification 1,426,512 is referred to.