A furnace may include at least two vertical shafts, each of which may have at an upper end thereof an inlet for material to be burnt and at a lower end thereof a burnt material outlet. The inlet and the outlet may be connected by a transfer channel. In each case, at least one main burner may be positioned above the transfer channel, and a cooling gas inlet may be positioned below the transfer channel. At least one additional burner may be positioned below the transfer channel in each of the shafts. Such a furnace can be operated such that the material to be burnt in the currently fired shaft is at least partially calcined in a main burning zone above the transfer channel, and then thermally aftertreated in an additional burning zone positioned between the transfer channel and the additional burner.

Installation including an industrial glass furnace (1) including a tank (2) for molten glass (3), a combustion heating chamber (4) situated above the tank (2), and a duct for evacuation of flue gases in communication with said heating chamber (4), and a stone furnace including a firing zone (21) for stone to be fired, the flue gas evacuation duct including a flue gas outlet that is connected to the firing zone (21) of stone to be fired and supplying the firing zone (21) of stone to be fired with flue gases at high temperature.

The present application provides a lime kiln apparatus recycling CO.sub.2 which includes a kiln body (100) and a heat-accumulating furnace set (20). The kiln body (100) defines no burner therein, and the heat-accumulating furnace set (20) provides hot CO.sub.2 (70) heated to a set temperature to the kiln body (100) for calcining mineral material, thereby finished lime is obtained. CO.sub.2 generated during the lime production is all recycled. After being dedusted, a part of the recycled CO.sub.2 is transported to the heat-accumulating furnace set (20) for heating, and is sent back to the kiln for calcining the mineral material after being heated to a temperature within a range of 800 C.-1200 C., and the other part of the recycled CO.sub.2 is recycled for use.

A furnace may include at least two vertical shafts, each of which may have at an upper end thereof an inlet for material to be burnt and at a lower end thereof a burnt material outlet. The inlet and the outlet may be connected by a transfer channel. In each case, at least one main burner may be positioned above the transfer channel, and a cooling gas inlet may be positioned below the transfer channel. At least one additional burner may be positioned below the transfer channel in each of the shafts. Such a furnace can be operated such that the material to be burnt in the currently fired shaft is at least partially calcined in a main burning zone above the transfer channel, and then thermally aftertreated in an additional burning zone positioned between the transfer channel and the additional burner.

A furnace may include at least two vertical shafts, each of which may have at an upper end thereof an inlet for material to be burnt and at a lower end thereof a burnt material outlet. The inlet and the outlet may be connected by a transfer channel. In each case, at least one main burner may be positioned above the transfer channel, and a cooling gas inlet may be positioned below the transfer channel. At least one additional burner may be positioned below the transfer channel in each of the shafts. Such a furnace can be operated such that the material to be burnt in the currently fired shaft is at least partially calcined in a main burning zone above the transfer channel, and then thermally aftertreated in an additional burning zone positioned between the transfer channel and the additional burner.

Burning and cooling carbonate rock in cocurrent regenerative lime kilns may involve alternately operating two shafts such that a first shaft operates as a burning shaft and a second shaft operates as a regenerative shaft during a first period and such that the first shaft operates as the regenerative shaft and the second shaft operates as the burning shaft during a second period. Carbonate rock introduced to upper regions of the shafts may be preheated and calcined. The carbonate rock may then be cooled in lower regions of the shafts before being discharged through discharge devices. The cooling of the carbonate rock may comprise introducing cooling air into the shafts partially through central displacement bodies in the shafts and partially through the discharge devices. Amounts of air entering through the central displacement bodies compared to the discharge devices may vary widely from the burning shaft to the regenerative shaft.

Burning and cooling carbonate rock in cocurrent regenerative lime kilns may involve alternately operating two shafts such that a first shaft operates as a burning shaft and a second shaft operates as a regenerative shaft during a first period and such that the first shaft operates as the regenerative shaft and the second shaft operates as the burning shaft during a second period. Carbonate rock introduced to upper regions of the shafts may be preheated and calcined. The carbonate rock may then be cooled in lower regions of the shafts before being discharged through discharge devices. The cooling of the carbonate rock may comprise introducing cooling air into the shafts partially through central displacement bodies in the shafts and partially through the discharge devices. Amounts of air entering through the central displacement bodies compared to the discharge devices may vary widely from the burning shaft to the regenerative shaft.

The present disclosure discloses a decarbonation process of limestone and dolomitic limestone with CO.sub.2 recovery in a multi-shaft vertical kiln (MSVK) having three shafts with preheating, heating and cooling zones and a cross-over channel between each shaft. The method includes alternately heating carbonated materials by a combustion of a fuel with a comburent up to a temperature range in which carbon dioxide of the carbonated materials is released, the combustion of the fuel and the decarbonation generating an exhaust gas, the decarbonated materials being cooled in the cooling zones with cooling stream(s). Mixing between the exhaust gas and the one or more cooling streams is minimized. The decarbonated materials in two or three of the shafts are cooled with the cooling streams while a supply of the fuel in each shaft is stopped.

The present disclosure discloses a decarbonation process of limestone and dolomitic limestone with CO.sub.2 recovery in a multi-shaft vertical kiln (MSVK) having three shafts with preheating, heating and cooling zones and a cross-over channel between each shaft. The method includes alternately heating carbonated materials by a combustion of a fuel with a comburent up to a temperature range in which carbon dioxide of the carbonated materials is released, the combustion of the fuel and the decarbonation generating an exhaust gas, the decarbonated materials being cooled in the cooling zones with cooling stream(s). Mixing between the exhaust gas and the one or more cooling streams is minimized. The decarbonated materials in two or three of the shafts are cooled with the cooling streams while a supply of the fuel in each shaft is stopped.

A method of operating a plant having a furnace including at least two vertical shafts connected by an overflow duct, wherein at least one burner is arranged above the overflow duct in each case such that the burner gases therefrom flow downward in burning operation of the respective shaft. A cooling gas supply is provided beneath the overflow duct in each case such that, in combination with the operation of a burner in the burner-operated shaft, the burner gas flowing downward is deflected in the direction of the overflow duct by the cooling gas ascending in the burner-operated shaft, and a supply of cooling gas is adjusted such that the temperature of the burner charge through which the burner gas flows at least in the burner-operated shaft is kept above the deacidification temperature thereof.