Patent ID: 8647113

Claim:
A method for manufacturing a cement clinker in a facility comprising: a rotary furnace; a cyclone preheater receiving the fumes from said rotary furnace; a clinker cooler, at the exit from said rotary furnace, in which cooler the clinker is blown-air cooled, generating hot air; at least a first exchanger, said method comprising: preheating and decarbonating raw materials in said cyclone preheater, the clinker coming out of the furnace is cooled in said clinker cooler; directing a first portion of the hot air generated in said clinker cooler to the rotary furnace to be used as combustion air, said first portion of hot air being secondary air; carrying a second portion of the hot air generated in said clinker cooler separately from said first portion to a place in the facility where fuel is burned to be used as combustion air, said second portion of hot air being tertiary air, defined by a temperature at least equal to 750° C.; directing and carrying a third portion of hot air generated in said clinker cooler in said at least first exchanger for the purpose of recovering power to produce electricity, said third portion of hot air being excess air, wherein: a second exchanger is provided, coacting with the tertiary air in order to heat a receiving fluid from a fluid circuit common to said first exchanger and to said second exchanger, wherein said second exchanger removes power from the tertiary air, thereby decreasing the temperature of the tertiary air from the upstream to the downstream portion of said second exchanger, whereas the tertiary air is used as combustion air downstream of said second exchanger, the heat transmitted by said second exchanger to said receiving fluid corresponding to the heat removed from the tertiary air generated in said clinker cooler.