GB819588A - Improvements in or relating to the production of purified carbonaceous material - Google Patents

Abstract

819,588. Electric furnaces. ALUMINIUM LABORATORIES Ltd. July 25, 1957 [Aug. 2, 1956], No. 23836/56. Class 39(3) [Also in Groups III and XII] Fine particles of anthracite, bituminous coal or coke from coal or petroleum are heated to 1100‹-1700‹C by passing current through a fluidized bed 3 of the particles between electrodes 7, 8, the particles being fluidized by a slowly upwardly moving current of gas which is ineffective to oxidize the carbon of the particles. The gas may include volatile gas liberated from the particles and a chlorinating agent and passes up at 5 through a diaphragm 4 to a gas outlet 6. The calcined carbon particles may be mixed with pitch to form electrodes for furnaces. The apparatus may comprise a steel casing 1 surrounding a refractory lining 2 enclosing a cylindrical graphite electrode 8 arid a central pendant electrode 7. Particles of uncalcined coke or of anthracite are fed to the fluidized bed 3 of calcined particles through a charging port 9 and withdrawn through a diametrically opposite outlet 10. The entering particles may be pre-heated by the withdrawn particles in a solid-tosolid fluid bed heat exchanger either separate from the heater or in a separate zone of the same apparatus. The gas withdrawn is passed through a cyclone dust separator, cooled and re-circulated to the heater at just above atmospheric pressure. Excess volatile gas freed from the coke is removed and burnt. The current is preferably A.C. and the voltage is regulated to maintain the required temperature. The heating removes sulphur from the coke or coal particles, especially at higher temperatures. Some ash, especially iron and silicon components, is removed by treatment in the fluidized bed with a chlorinating agent e.g. chlorine gas, which may be added to the fluidizing gas or be used alone. The treatment of coke with chlorine may take place in batches or continuously and simultaneously with calcination or subsequently thereto, e.g. when hot. The heater may be of inverted conical shape so that the velocity of the rising gas drops, whereby a large range of sizes of particles is maintained fluidized.