Method and apparatus for calcining lime
First Claim
1. In a method for calcining calcium bearing raw material in which finely divided raw material is successively treated in a preheating zone, a generally vertical calcining zone, and a cooling zone wherein the finely divided raw material is preheated in said preheating zone by exhaust gases from said calcining zone, passed through said calcining zone, and then in suspension through said cooling zone, the entire amount of cooling air being supplied directly from the cooling zone into the calcining zone as combustion air, the improvement which comprises:
- adding fuel to said generally vertical calcining zone at a plurality of locations following one another in the upward and onward flow direction of the gas passing through said calcining zone, introducing the preheated raw material closely adjacent to the lowest of said locations for immediate calcining effect at said lowest location, and passing the preheated raw material vertically upwardly through the calcining zone in concurrent flow with the fuel and while suspended in the gas stream.
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Abstract
A method and apparatus for calcining lime, dolomite or similar materials in which the raw material to be calcined is preheated in a preheating zone by exhaust gases from a calcining zone, cooled by means of combustion air in a cooling zone, the combustion air passing from said cooling zone into said calcining zone and then into the preheating zone. A specific improvement of the invention resides in adding fuel in the calcining zone at a plurality of spaced locations along the calcining zone in the direction of flow of the combustion air therethrough.
25 Citations
8 Claims
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1. In a method for calcining calcium bearing raw material in which finely divided raw material is successively treated in a preheating zone, a generally vertical calcining zone, and a cooling zone wherein the finely divided raw material is preheated in said preheating zone by exhaust gases from said calcining zone, passed through said calcining zone, and then in suspension through said cooling zone, the entire amount of cooling air being supplied directly from the cooling zone into the calcining zone as combustion air, the improvement which comprises:
adding fuel to said generally vertical calcining zone at a plurality of locations following one another in the upward and onward flow direction of the gas passing through said calcining zone, introducing the preheated raw material closely adjacent to the lowest of said locations for immediate calcining effect at said lowest location, and passing the preheated raw material vertically upwardly through the calcining zone in concurrent flow with the fuel and while suspended in the gas stream. - View Dependent Claims (2, 4, 5, 6, 7, 8)
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3. A method according to claim 3 in which:
said pulsing occurs at a frequency of from 0.5 to 5 Hz.
Specification