Cement burning plant

Claim 1

An apparatus for burning cement clinker and comprising a preheater (1,2,3) and an inlet (4) and an outlet (5) for heating gas and an inlet (6) and an outlet (7) for pulverous cement raw material; a suspension calciner (8,9) with inlets (10,11) for fuel, combustion air and preheated raw materials, an outlet for combustion gas connected to the heating gas inlet (4) of the preheater, and an outlet (12) for calcined material, communicating with a material inlet (17) of a sintering furnace (13) with an inlet-for fuel (16) and combustion air, an outlet (20) for combustion gas communicating with the heating gas inlet of the preheater and an outlet for the sintered product connected to a material inlet of an air cooler (18) for cooling the sintered product with an air outlet (21) connected to both the air inlet of the sintering furnace and the air.inlet of the suspension calciner; characterized in that the sintering furnace comprises a cylindrical member (14) rotatable about an axis which is slightly inclined to the horizontal and providing a sintering drum; a suspension inlet duct (15) provided with a material inlet (17) and having a first end connected to the air outlet (21) of the cooler and a second end leading to the upper end of the sintering drum in a plane substantially tangential to the inner circumferential surface of the sintering drum; a fuel inlet or inlets (16,19) leading into the suspension inlet of the sintering drum (14) and/or into the suspension inlet duct (15); a combustion gas outlet. duct (20) connected to one end of the sintering drum; and an outlet for the sintered product at the lower end of the sintering drum.

Claim 2

An apparatus for burning cement clinker and comprising a preheater (1,2,3) and an inlet (4) and an outlet (5) for heating gas and an inlet (6) and an outlet (7) for pulverous cement raw material; a suspension calciner (8,9) with inlets (10,11) for fuel, combustion air and preheated raw materials, an outlet for combustion gas connected to the heating gas inlet (4) of the preheater, and an outlet (12) for calcined material, communicating with a material inlet (17) of a sintering furnace (13) with an inlet-for fuel (16) and combustion air, an outlet (20) for combustion gas communicating with the heating gas inlet of the preheater and an outlet for the sintered product connected to a material inlet of an air cooler (18) for cooling the sintered product with an air outlet (21) connected to both the air inlet of the sintering furnace and the air.inlet of the suspension calciner; characterized in that the sintering furnace comprises a cylindrical member (14) rotatable about an axis which is slightly inclined to the horizontal and providing a sintering drum; a suspension inlet duct (15) provided with a material inlet (17) and having a first end connected to the air outlet (21) of the cooler and a second end leading to the upper end of the sintering drum in a plane substantially tangential to the inner circumferential surface of the sintering drum; a fuel inlet or inlets (16,19) leading into the suspension inlet of the sintering drum (14) and/or into the suspension inlet duct (15); a combustion gas outlet. duct (20) connected to one end of the sintering drum; and an outlet for the sintered product at the lower end of the sintering drum.

Claim 7

an apparatus according to any one of claims 3, 4 to 5, characterized in that the combustion gas outlet (20) is connected to the lower end of the sintering drum (14) and that the outlet for the sintered product, the lowest part of the sintering drum and the combustion gas outlet provide the connection (21) between the air outlet of the cooler and the air inlet of the suspension calciner.

Claim 9

An apparatus according to any one of the preceding claims,'characterized in that the tangential relationship between the second end of the suspension inlet duct (15) and the upper end of the sintering drum is provided via a stationary cylindrical member (22) which is coaxial with and smaller in diameter than the sintering drum and which provides a spiral flow chamber with a tangential suspension inlet (15) and an axial suspension outlet (23) communicating with the sintering drum.