Metallgesellschaft Aktiengesellschaft

Stora Kopparbergs Bergslags Ab

Stora Kopparbergs Bergslags Aktiebolag

Sune N Flink

Martin Hirsch

Lothar Reh

Bjorn Widell

Per H Collin

Per Harald Collin

Erik A Bengtsson

Apparatus for reducing finely divided iron oxide material

Carbonaceous material, preferably coal or like finely divided solids with a mean particle diameter of 30 to 250 microns, is burned to produce steam in a fluid-bed furnace having a lower free space without internal fixtures and provided above this free space with internal cooling surfaces. A secondary-gas inlet introduces the secondary gas so that the volume ratio of fluidizing gas to secondary gas ranges from 1:20 to 2:1 at a location above the fluidizing-gas and fuel inlets but below the internal cooling surfaces, the gas velocity of the several gases being adjusted so that the mean suspension density of the solids above the secondary-gas inlet is 15 to 100 kg/m.sup.3. Approximately stoidiometric conditions are maintained with respect to the oxygen in the gases introduced and the carbonaceous material and solids are recycled to the bed after being separated from the gases emanating therefrom.

Process for burning carbonaceous materials

A method of reducing a pulverized material containing iron oxides mixed with carbonaceous material wherein: (a) a circulating fluidized bed is maintained in a vertically elongated reaction zone by supplying it with suitable quantities of pulverized material containing iron oxides, pulverized solid carbonaceous material and optionally liquid carbonaceous material, and gas containing molecular oxygen and that gas and solid material leaving the reaction zone are separated, the solid material being returned to the reaction zone; (b) the pulverized material containing iron oxides, the carbonaceous material and the gas containing molecular oxygen are supplied to an intermediate section of the reaction zone; (c) the flow of carbonaceous material fed to the bed is controlled so that there is always sufficient coke in the bed to prevent interference of the fluidization caused by sticking or agglomeration; (d) gas and solid material leaving the reaction zone are extracted from the upper part of the reaction zone, the solid material being separated from the gas and being returned to the intermediate section of the reaction zone; (e) a portion of the gaseous reaction zone exhaust, after dust separation and elimination of most of carbon dioxide and water, is fed to the lower part of the reaction zone as fluidizing and reduction gas; and (f) solid material containing completely or partially reduced iron oxides is drawn from the lower part of the reaction zone.

Method for reducing material containing iron oxides

Growing community of inventors

Vasteras, Sweden

Sune N Flink