F. L. Smidth & Co.

Rolf Dietrich Houd

Hans B Knudsen

A plant for manufacturing cement clinker from cement raw material includes a preheater first stage separated by a wall into a first chamber and a second chamber. Only raw material is passed through the first chamber while only hot exit gases are permitted to pass through the second chamber. Thus the raw material including any volatile, combustion components are kept isolated from direct contact with the hot exit gases. A heat exchange system is provided to permit the transfer of heat from the hot exit gases in the second chamber to the raw material in the first chamber. The heat exchange system preferably includes self-contained heat pipes extending into both the first and second chambers. The heat pipes contain a fluid medium which aids in the heat transfer as a consequence of cylical changes of the fluid medium from a liquid to a vapor state. In one preferred embodiment to obtain improved heat transfer, granular heat-resistant material is placed within the second chamber and is formed into an expanded fluidized bed.

Plant for manufacturing cement clinker

A method is disclosed for burning pulverous or granular raw material such as cement raw meal in a rotary kiln plant by directing a first flow of raw material to a cyclone preheater, preheating the first flow of raw material in the cyclone preheater, and directing the preheated raw material from the cyclone preheater to a rotary kiln for burning the material in the kiln. The burnt kiln product is directed to a cooler which may be of several types and which communicates with the material outlet of the kiln while a second flow of fresh raw material is directed to the cooler to at least partially cool the burnt kiln product by transferring heat therefrom to the second flow of fresh raw material in the cooler. The method further involves combining the preheated, at least partially calcined second flow of material with the first flow of preheated, at least partially calcined material prior to directing the combined flows to the rotary kiln and thereafter directing the combined flows to the kiln for burning and for subsequent cooling in the cooler. The invention also pertains to a unique kiln plant for practicing the inventive method.

Burning of pulverous or granular raw materials

A rotary kiln plant for calcining and sintering mineral materials such as cement raw materials, comprising a separate unit for preheating and at least partially calcining the raw materials, a rotary kiln for sintering the preheated and calcined raw materials, a separate inside airswept rotary cooler means for cooling the materials burnt in the kiln, and a stationary chamber positioned intermediate the outlet of the rotary kiln and the inlet of the rotary cooler means and forming a passage for the burnt kiln product from the kiln to the rotary cooler means in countercurrent with heated cooling air passing to the rotary kiln. Air inlet and outlet means on the chamber make it possible to introduce additional cooling air and to utilize cooling air from the chamber for the preheating and calcining unit while by-passing the rotary kiln.

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Copenhagen, Denmark

Rolf Dietrich Houd