Cooler

Abstract

The present invention discloses a cooler for cooling particulate material which has been subjected to heat treatment in an industrial kiln, such as a rotary kiln for manufacturing cement clinker. This cooler comprises an inlet, an outlet, end wall, side walls, a bottom and a ceiling, at least three reciprocating supporting lanes for receiving, supporting and transporting the material to be cooled, the lanes are moving following the walking floor principles as well as means for injecting cooling gas into the material through grate plates in the lanes. With the present invention it is an aim to have an increase in the vertical shearing height, and still having stationary clinker on top of the grate plates.

Claims

1. A cooler (1) for cooling particulate material (2) which has been subjected to heat treatment in an industrial kiln (3), such as a rotary kiln for manufacturing cement clinker, which cooler (1) comprises an inlet (4), an outlet (5), end walls (6), side walls (7), a bottom (8) and a ceiling (9), at least three reciprocating supporting lanes (10) for receiving, supporting and transporting the material to be cooled, the lanes (10) are moving following the walking floor principles, cooling gas is injected upwards between the bottom (8) and the lanes (10), the cooling gas is going through grate plates (12) in the lanes (10), the cooling gas is then passing through the material (2) and where at a distance from the inlet a heat recuperation boarder is established such that air on the inlet side of the heat recuperation boarder (11) will return to the kiln (3) wherein elements 16 extend upwards from an upper surface of the supporting lanes, where the elements (16) on a supporting lane are spaced creating a grate plate zone G (13), which element has an upper part L which is tilted towards the outlet (5) end of the cooler, which upper part has a length L (17) which is more than 1/40 of G (13) and where the upper part L has an angle alpha (18) which is more than 5 deg. and less than 80 deg. between the upper part L and horizontal.

2. A cooler according to claim 1, wherein the length L (17) is more than 1/20 of G (13) and the angle alpha (18) is more than 5 deg. and less than 80 deg.

3. A cooler according to claim 1, wherein the length L (17) is more than 1/10 of G (13) and the angle alpha (18) is more than 5 deg. and less than 80 deg.

4. A cooler according to claim 1, wherein the length L (17) is more than ⅕ of G (13) and the angle alpha (18) is more than 5 deg. and less than 80 deg.

5. A cooler according to claim 1, wherein the length L (17) is more than 1/40 of G (13) and the angle alpha (18) is more than 15 deg. and less than 80 deg.

6. A cooler according to claim 1, wherein the length L (17) is more than 1/20 of G (13) and the angle alpha (18) is more than 15 deg. and less than 80 deg.

7. A cooler according to claim 1, wherein the length L (17) is more than 1/10 of G (13) and the angle alpha (18) is more than 15 deg. and less than 80 deg.

8. A cooler according to claim 1, wherein the length L (17) is more than ⅕ of G (13) and the angle alpha (18) is more than 15 deg. and less than 80 deg.

Description

BRIEF INTRODUCTION OF THE DRAWINGS

(1) FIG. 1 illustrates a plain view of a cooling installation according to the invention;

(2) FIG. 2 illustrates a vertical cross section through the same installation as illustrated in FIG. 1;

(3) FIG. 3 illustrates that a cooling floor is provided with five reciprocating supporting lanes;

(4) FIG. 4 illustrates a close-up of the reciprocating support lanes;

(5) FIG. 5 illustrates a forward tilted section that increased bed height may be achieved providing a vertical shear without causing the cold channel problem.

DETAILED DESCRIPTION

(6) In FIG. 1 is illustrated a plain view of a cooling installation 1 connected to a rotary kiln 3. In FIG. 2 is indicated a vertical cross section through the same installation where it may be seen that the rotary kiln is arranged above the cooling installation. The rotary kiln 3 is heated by a flame indicated by the hatched section and when cement clinker has been exposed to the heat treatment in the kiln it will for example be due to the inclination of the kiln be delivered onto an inlet end 4 of the cooling installation.

(7) The layer of clinker is indicated by the light grey line 2 which thereby indicates particulate material. Opposite the inlet end is provided an outlet end 5 where the cooling floor as such is housed in a housing comprising walls 6, side walls 7, a bottom 8 and a ceiling 9. For the sake of explanation the present invention will be explained with respect to a cooling installation comprising three reciprocating supporting lanes 10. In this context please refer to FIG. 3 where it is illustrated that a cooling floor is provided with five reciprocating supporting lanes 10.

(8) The particulate material 2 will be transported on the reciprocating supporting lanes according to the walking floor principle. The walking floor principle is very well-known for these types of cooling floors and does transport the particulate material from the inlet end to the outlet end by simultaneously pushing at least three reciprocating supporting lanes forward at the same speed. Thereafter two of the sliding lanes remain in position while the sliding lane positioned between these two sliding lanes is withdrawn.

(9) Due to the friction between the particulate material not all the particulate material will be withdrawn during this movement such that the net effect of this reciprocating movement will be that the particulate material 2 is moved from the inlet 4 towards the outlet 5.

(10) The sliding/reciprocating supporting lanes are provided with grate plates such that a cooling gas blown into the space between the bottom 8 of the cooling device and the grates in the sliding floor will be able to pass the supporting lanes. Due to the pressure in the gas being forced into the space between the bottom and the supporting lanes the gas will be forced up through the particulate material layer. Thereby the cooling gas will heat exchange with the very hot particulate material which has just left the kiln and move heat away from the particulate materials which is thereby cooled.

(11) After the gas has passed the particulate material a portion of the gas will be led back to the kiln in order to help heat the clinker material inside the kiln thereby saving energy. Traditionally, there will be a heat recuperation border 11 which is delimiting the distance from the kiln where the gas which is passed through the particulate material will be led back through the kiln. Gas beyond this point will be led to a chimney as indicated by the arrows.

(12) Turning to FIG. 4 a close-up of the reciprocating support lanes is indicated. The grate plates 12 are provided in the cooling supporting lanes in order to allow the cooling gas to pass through the supporting lanes 10.

(13) Upstanding from the surface of the supporting lanes are elements 16 which extend upwards. These elements 16 are positioned with a certain space thereby creating grate plate zones 13. Particulate material between these upstanding elements will be stationary and as such as the reciprocating support lanes move back and forth the particulate material will not wear and tear on the sliding/reciprocating support lanes, but will only roll on top of the particulate material already caught in the grate plate zone.

(14) The elements 16 are provided with an upper part L which is tilted towards the outlet 5. In this manner the effects relating to the movement of the particulate material as explained above will be obtained. It is clear that the tilted section having a length L will create a shadow for the gas passing out through the grate plates such that the cooling above the tilted section 17 will be less efficient.

(15) As explained above with reference to recuperation of heat and the clinker bed height it is advantageous to have a relatively thick clinker layer/particulate material layer, but at the same time to have vertical shearing in order to create a certain resistance for the gas passing through the particulate material thereby improving the heat recuperation. This is achieved by the forward tilted section which is illustrated in FIG. 5 such that increased bed height may be achieved providing a vertical shear without causing the cold channel problem which is a channel through the particulate material allowing the air to pass more or less unhindered through the particulate material whereby the heat recuperation is severely diminished. Therefore, when a cold channel is established the heat recuperation is diminished and the cooling effect of the entire clinker bed is severely diminished. This leads to overall bad performance and a lack of recuperation of heat which could otherwise be reused in the kiln.