Method and Cooler for Cooling Hot Particulate Material

Abstract

A method as well as a cooler for cooling hot particulate material which has been subjected to heat treatment in an industrial kiln, such as a rotary kiln for manufacturing cement clinker may be configured such that hot material from the kiln is directed onto a grate in a cooler where cooling gases via at least one cooling gas duct are directed through slots in the grate for cooling the hot material and where compressed air can be injected into the material on the grate. The method as well as the cooler is characterized in that compressed air is injected into the cooling gas duct. The compressed air which is injected into the cooling gas duct may operate as a non-return valve which can ensure that compressed air is injected into the material on the grate and may prevent clinker dust from falling through the cooling gas duct.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is the United States national stage under 35 U.S.C. §371 of International Application No. PCT / EP2009 / 055887, filed on May 15, 2009, claiming priority to Danish Application No. PA 2008 00879, filed on Jun. 26, 2008. Both of those applications are incorporated by reference herein.FIELD OF INVENTION[0002]The present invention relates to a method for cooling hot particulate material which has been subjected to heat treatment in an industrial kiln, such as a rotary kiln for manufacturing cement clinker, whereby the hot material from the kiln is directed onto a grate in a cooler where cooling gases via at least one cooling gas duct are led through slots in the grate for cooling the hot material and where compressed air can be injected into the material on the grate. The invention also relates to a cooler for carrying out the method.BACKGROUND OF THE INVENTION[0003]A cooler of the above mentioned kind is known from EP 1 774 236 ...

AI Technical Summary

Benefits of technology

[0004]It is the object of the present invention to provide a method as well as a cooler for cooling hot particulate material whereby the aforementioned disadvantage is eliminated.

[0006]Embodiments of the method and cooler permit the compressed air which is injected into a cooling gas duct to operate as a non-return valve which will ensure that compressed air is injected into the material on the grate. This is due to the fact that the mass flow inertia and the dynamic pressure of the compressed air being injected into the cooling gas duct will prevent a backflow of the compressed air in the cooling gas duct. The blanking-off of the cooling gas duct thus achieved will further prevent clinker dust from falling through the cooling gas duct.

[0008]In principle, the compressed air may be injected into the cooling gas duct at any conceivable angle relative to the centerline of the cooling gas duct. Preferably, the compressed air should be injected into the cooling gas duct with a velocity component which is parallel to the centerline of the cooling gas duct and pointing in direction towards the grate, which means that the compressed air must be injected at an angle α of less than 90° relative to the centerline of the cooling gas duct. It is believed that such an injection of compressed air provides the best effect. It is preferred that the compressed air is injected at an angle α of less than 10°, preferably at an angle of 0° relative to the centerline of the cooling gas duct.

Problems solved by technology

The disadvantage of this known cooler is that the valve arrangement is a mechanically movable component which may wear out relatively quickly when exposed to compressed air in expansion, consequently giving rise to operational problems.

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