Rotary Kiln and Method for Burning Carbonate-Containing Material, in Particular Limestone or Dolomite

Patent metadata

Field	Value
Publication number	US-2024077257-A1
Application number	US-202218280343-A
Country	US
Kind code	A1
Filing date	Mar 7, 2022
Priority date	Mar 5, 2021
Publication date	Mar 7, 2024
Grant date	—

Abstract

The present invention relates to a rotary kiln for burning carbonate-containing material, in particular limestone or dolomite, including a rotary tube with an inlet end for the feeding of the material to be burned and an outlet end for the discharging of the burned material, the rotary tube having an inlet zone at its inlet end and an outlet zone at its outlet end wherein a preheating zone and a combustion zone are arranged between the inlet zone and outlet zone, the rotary kiln being characterized according to the invention in that in the inlet zone of the rotary tube at least one projection is provided, the at least one projection having at least one sliding surface inclined to the longitudinal axis of the rotary tube for conveying the material to be burned from the inlet zone into the preheating zone. The present invention further relates to a method for burning carbonate-containing material, in particular limestone or dolomite.

First claim

1 - 15 . (canceled)

16 . A rotary kiln for burning carbonate-containing material, in particular limestone or dolomite, comprising a rotary tube with an inlet end for the feeding of the material to be burned and an outlet end for the discharging of the burned material, the rotary tube having an inlet zone at its inlet end and an outlet zone at its outlet end a outlet zone, a preheating zone and a combustion zone being arranged between the inlet zone and outlet zone, wherein
in the inlet zone of the rotary tube a plurality of projections are provided, each projection of the plurality of projections having at least one sliding surface inclined to the longitudinal axis of the rotary tube for conveying the material to be burned from the inlet zone into the burning zone, wherein the projections are arranged in a row as a group in such a way that the respective sliding surfaces of the projections form a common sliding surface for the material to be burned.

17 . The rotary kiln according to claim 16 ,
wherein the at least one sliding surface of the at least one projection has an inclination to the longitudinal axis of the rotary tube from 15° to 70°, in particular from 25° to 65°, especially from 35° to 55° and particularly preferably from 40° to 50°.

18 . The rotary kiln according to claim 16 ,
wherein the at least one projection contains a refractory material, the refractory material being concrete, in particular refractory concrete.

19 . The rotary kiln according to claim 16 ,
wherein the at least one projection has a prismatic geometry, optionally the at least one projection being designed as a straight prism with a triangular base.

20 . The rotary kiln according to claim 16 ,
wherein the at least one projection has a height extending in the radial direction of the rotary tube of 100 mm to 500 mm, in particular of 140 mm to 400 mm, preferably of 160 mm to 300 mm and particularly preferably of 180 mm to 250 mm, and/or the at least one projection has a length extending substantially parallel to the longitudinal axis of the rotary tube of 100 mm to 2000 mm, in particular 150 mm to 1000 mm, preferably 300 mm to 500 mm and very particularly preferably 350 mm to 450 mm, and/or the at least one projection is attached by means of a metallic anchoring, in particular a welded metallic anchoring, to the inner side of the rotary tube shell.

21 . The rotary kiln according to claim 16 ,
wherein the common sliding surface formed by the plurality of projections extends substantially over the entire length of the inlet zone.

22 . The rotary kiln according to claim 21 ,
wherein the common sliding surface for the material to be burned can be provided by 3 to 9 projections, in particular by 4 to 8 projections, especially by 5 to 7 projections and very particularly preferably by 6 projections.

23 . The rotary kiln according to claim 21 ,
wherein the plurality of projections are formed substantially identically to one another, such that a common sliding surface is formed with a substantially constant slope, and/or the plurality of projections are arranged in rows in a stepped form as a group along the inlet zone.

24 . The rotary kiln according to claim 16 ,
wherein 2 to 8, in particular 3 to 7, especially 4 to 6 and very particularly preferably 5 projections or groups of projections, are arranged in a row over the circumference of the rotary tube.

25 . The rotary kiln according to claim 16 ,
wherein the rotary tube has at least one further projection, preferably a plurality of further projections, in the region of the preheating zone for more rapid passage of the material to be burned through the preheating zone and for reducing the formation of dust.

26 . The rotary kiln according to claim 25 ,
wherein a plurality of further projections are provided in the region of the preheating zone, the further projections being arranged as groups substantially parallel to the longitudinal axis of the rotary tube, wherein, optionally, further projections arranged adjacent to one another in the circumferential direction of adjacent groups of further projections are arranged offset from one another in the longitudinal direction of the rotary tube in such a way that spiral-shaped transport paths are formed for the material to be burned.

27 . The rotary kiln according to claim 16 ,
wherein the rotary tube has at least one additional projection, preferably a group of additional projections, in the region of the outlet zone, in order to prevent the formation of clusters in the burned material.

28 . The rotary kiln according to claim 27 ,
wherein a plurality of additional projections are provided in the region of the outlet zone, the additional projections being arranged as groups in the circumferential direction of the rotary tube, preferably offset from one another in the longitudinal direction of the rotary tube, wherein, optionally, a plurality of groups of additional projections are provided in the longitudinal direction of the rotary tube.

29 . A method for burning carbonate-containing material, in particular limestone or dolomite
wherein the following steps:
introducing the carbonate-containing material into the rotary tube of a rotary kiln according to claim 16 ,
burning the carbonate-containing material, the carbonate-containing material moving through the rotary tube from the inlet zone and the burning zone to the outlet zone, the rotary tube rotating in a direction of rotation,
conveying the carbonate-containing material from the inlet zone into the preheating zone, in that the carbonate-containing material rests at least partially on the common sliding surface of the plurality of projections, which is inclined to the longitudinal axis of the rotary tube, and slides, driven by gravity, in the direction of the preheating zone.

Assignees

• Lhoist Rech Et Developpement Sa

Inventors

• Kaczinski Carsten

Classifications

• F27B7/162 Primary

  the projections consisting of separate lifting elements, e.g. lifting shovels · CPC title

• C04B2/10

  Preheating, burning calcining or cooling (decarbonation during burning of cement raw materials C04B7/43; {obtaining CaO or MgO otherwise than by thermal decomposition of the corresponding carbonates C01F11/02, C01F5/02}) · CPC title

• F27B2007/165

  forming a helical lifting projection · CPC title

• F27M2003/03

  Calcining · CPC title

• Y02P40/40

  Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills · CPC title