GB734041A - Production of useful combustible gas from caking bituminous fuels - Google Patents

Abstract

A mixture of finely-divided coking coal and ore of a still finer grain size is coked and the metalliferous product, freed from fine grains which may be returned to the ovens, gasified in a low shaft furnace operated as a slagging producer with air or oxygen with or without steam, carbon dioxide, &c., metal and slag being separately withdrawn in fluid state. Heavy mineral or tar oil, pitch, asphalt, &c., e.g. about 1-3 per cent by weight, may be added to the mixture to be coked. If the coke is gasified with oxygen and preheated steam the gas may be carburetted or methanized to yield a town gas and mixed with the coke oven gas. Coals giving an insufficiently hard coke may be mixed with under 3 per cent of ore of the highest oxidation stage and heated to 10 DEG C. or more before coking. The air blast may be heated by the gas produced which may be used for underfiring the coke ovens, or, with a reduced demand for coke oven gas the total amount distilled may be compressed and freed from benzene, the proportion not required then being diverted to the ovens. The coal with a grain size below 5 mm. and preferably below 2 mm. may amount to 50-80 per cent by weight of the mixture and the ore grains are preferably below 1 mm. The coke may have an iron content of preferably about 30 per cent. In an example, a gas-rich coal coked with iron ore contains 60 per cent of coke lumps of 60 mm. and 33 and 7 per cent respectively sized above and below 10 mm. The largest sizes may be introduced into normal blast furnaces and the remainder above 10 mm. gasified in the producer. Carbon dioxide may be supplied to the glowing coke in the oven to increase the quantity of gas released.