Method of calcining sinterable materials to form cement clinker or the like
AssigneeBabcock Krauss-Maffei Industrieanlagen GmbH
InventorWolfram G. Quittkat
Life of this patent
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Abstract
Carbonate-containing sinterable material, e.g. for cement clinker, is calcined in a rotary kiln and then cooled in a grate cooler. The material is subjected to preheating in a suspension preheater and then to precalcination in an upright precalcining installation. The fuel for the latter is introduced through nozzles into a substantially oxygen-free crude power exhaust gas suspension and after turbulent mixing of the fuel with this suspension a stoichiometric quantity of combustion air is introduced so that a flameless combustion occurs in the turbulent mixture. Thereafter the solids enter the rotary kiln for the final calcination.
Claims5
A method of firing sinterable powder having a carbonate component, comprising the steps of:
- (a) preheating said powder by suspension thereof in a hot gas;
- (b) precalcining the preheated powder of step (a) by:
- (b.sub.1) forming a turbulent mixture of particles of the powder and said gas substantially in the absence of free oxygen with a substantially vertical axis,
- (b.sub.2) spraying fuel laterally into said turbulent mixture thereby dispersing it optimally and depositing said fuel at least in part upon the particles of said powder,
- (b.sub.3) while maintaining the turbulence of this mixture laterally adding a stoichiometric quantity of oxygen with respect to said fuel to effect a flameless oxidation of the fuel and heat the particles to a temperature sufficient for substantially complete decarbonatization thereof;
- (c) calcining the particles treated in step (b) in a rotary kiln to form clinker;
- (d) cooling the clinker formed in step (c) with an oxygen-containing gas thereby heating the oxygen-containing gas;
- and
- (e) feeding at least a portion of the oxygen-containing gas heated in step (d) to step (b.sub.3) to supply the oxygen therefor.
Dependencies are inferred from the claim text.