Patent ID: 8974596
Filing Date: 2015-03-10
Classification: C04B,F27B,F27D,Y02P

Abstract:
1. A method for producing cement clinker, comprising the following steps: grinding calcium carbonate-containing initial material into calcium carbonate-containing raw meal in a grinding stage; deacidifying the raw meal and generating exhaust gases; sintering the raw meal into cement clinker in a sintering stage and generating exhaust gases; combining the exhaust gases from the sintering stage with the exhaust gases from deacidification in a first open gas circuit; preheating the raw meal in a preheating stage prior to deacidifying by the combined exhaust gases from the sintering stage and the deacidification; cooling the cement clinker from the sintering stage in a cooling stage, the cement clinker being cooled by circulation air in a separate second open gas circuit, wherein the circulation air becomes heated and is delivered to the grinding stage; transferring heat from the combined exhaust gases from the preheating stage in the first open gas circuit to the circulation air from the grinding stage in the second open gas circuit without mixing the gases between the first and second gas circuits, such that the combined exhaust gases are cooled, and simultaneously the circulation air is reheated by the heat transfer; after the heat transfer, combining the reheated circulation air with the circulation air heated in the cooling stage such that the combined circulation air is introduced into the grinding stage to dry the raw meal; separating a fraction of the combined exhaust gases from the first open gas circuit, a quantity fraction of the separated fraction of the combined exhaust gases corresponding to a fraction which is newly added to the first open gas circuit in the first open gas circuit as a result of combustion and deacidification; and separating a fraction of the circulation air from the second open gas circuit, a quantity fraction of the separated fraction of the circulation air corresponding to a fraction which is newly added to the second open gas circuit in the second open gas circuit as a result of atmospheric air intake at the cooling stage.