Method for producing cement clinker in a plant, and plant for producing cement clinker as such

A method for manufacturing cement clinker in a facility comprising:

• a first cyclone preheater (5) and a second cyclone preheater (7) for preheating first (4) and second (6) portions of a raw material, respectively,
• a precalcinator (1) using a combustion gas (9) for burning a solid fuel, the fumes (8) released by said precalcinator (1) being directed to said second cyclone preheater (7),
• a rotary furnace (2) provided with a fuel burner, the fumes (18) released by the rotary furnace (2) being directed to the first cyclone preheater (5), said first cyclone preheater (5) and second cyclone preheater (7) being independent so that fumes from the kiln and fumes from the precalcinator do not mix, and
• a clinker cooler (3) that blows a cooling gas across the clinker at the outlet of said rotary furnace (2),
• wherein said method comprises:
• reheating the first portion (4) of raw material in the first cyclone preheater (5);
• preheating the second portion (6) of raw material in the second cyclone preheater (7);
• pre-roasting the totality of the first preheated portion of raw material (41) and the second preheated portion of raw material (61) in the precalcinator (1) with said solid fuel and said combustion gas (9) before firing the pre-roasted materials in the rotary furnace (2) and cooling the fired materials in said clinker cooler (3),
• said combustion gas (9) in the precalcinator (1) containing between 90% and 100% oxygen by volume, the precalcinator (1) being a fluidised bed (13), the fluidisation gas being said combustion gas,
• said solid fuel having a grain size of greater than or equal to 1 mm, in part or whole, and
• the materials (4, 6) being pre-roasted in the precalcinator (1), without recycling fumes in said precalcinator (1) in order to concentrate carbon dioxide in the fumes from the second cyclone preheater (7), the carbon dioxide concentration being greater than 75% by volume.