The present invention relates to apparatus for thermal treatment of a mineral starting material, wherein the apparatus comprises a calciner, wherein the calciner comprises at least a first calciner section and a second calciner section, wherein the first calciner section is arranged vertically, wherein the second calciner section is arranged at an incline, wherein the second calciner section has an angle ? between the horizontal and the flow direction of the second calciner section, wherein the angle ? is between 20? and 80?, wherein the first calciner section has a first hydraulic diameter d.sub.h,1, wherein the second calciner section has a second hydraulic diameter d.sub.h,2, wherein the second hydraulic diameter d.sub.h,2 is less than or equal to the first hydraulic diameter d.sub.h,1 multiplied by the sine of the angle ?.

A pot furnace for calcining petroleum coke at low temperature may include a pot, and a cooling water jacket and a flame path below the pot. The flame path may include eight layers. An inlet of a first flame path layer may be in communication with a volatile channel in the front wall, and is provided with a first flame path layer flashboard An eighth flame path layer may be in communication with a communication flue. Flue gas may be discharged out of the furnace body through a main flue. A furnace bottom cooling channel may be provided below the eighth flame path layer.

A process for calcining a feed material can include passing a solid particulate material through a burner or adjacent a burner for being pass through a flame formed by the burner to facilitate calcination of the material. The material can be emitted from the flame of the burner within a calciner for passing through a body of the calciner to an outlet for further calcination of the material so the material has a pre-selected residence time as it is passed through the flame and calciner to an outlet. The residence time can be 20 seconds to 30 seconds, 1-3 minutes, less than 5 minutes in some embodiments. Some embodiments can facilitate calcination of a CaCO.sub.3 material so the calcined solid material output from a calciner is comprised of Ca(OH).sub.2 (e.g. is mostly Ca(OH).sub.2, is over 90 weight percent Ca(OH).sub.2, etc.).

A method for producing lime or dolime, which includes a calcination step for the calcination of calcareous or dolomitic material which is brought into contact with the first fumes which are obtained by combustion of fuel with an oxidizing gas, a cooling of calcined lime or dolime with discharge and collection thereof and a release of a gaseous effluent containing CO.sub.2. Subsequent processing steps result in the formation of a CaO-based sorbent material with separation between the CaO-based sorbent material and a CO.sub.2-concentrated gas stream which is collected. The recycling of said separated CaO-based sorbent material is recycled into a CO.sub.2 depletion step resulting in the extraction of a valorizable fraction of the CaCO.sub.3CaO based charge with a compensatory introduction of fresh CaCO.sub.3 in the calcination step.

The present disclosure relates to a decarbonation process of carbonated materials, in particular limestone and dolomitic limestone, with CO.sub.2 recovery in a multi-shaft vertical kiln (MSVK) comprising a first and a second shaft 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 at least one fuel with at least one 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. Decarbonated materials are cooled in the cooling zones with one or more cooling streams. The process further includes extracting the exhaust gas from the multi-shaft vertical kiln and feeding a buffer with the extracted exhaust gas.

A calcination unit able to decarbonate raw materials intended for clinker production, the unit including: a main duct in which the raw materials circulate according to a first movement direction, the raw materials being calcined in the main duct; a solid fuel supply duct opening onto the main duct via a fuel outlet, the solid fuel moving according to a second movement direction; a retaining device located in the main duct and arranged opposite the solid fuel outlet so that the solid fuel arriving in the main duct via the fuel outlet passes through the retaining device.

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.

This invention discloses a calcination process to produce high purity CO.sub.2 from solids containing CaCO.sub.3 which operates cyclically and continuously on the solids, arranged in a packed or a moving bed, and wherein each cycle comprises a first step where the combustion at atmospheric pressure of a fuel in the bed of solids containing CaCO.sub.3 heats them up to 800-900? C. and a second step wherein a vacuum pressure between 0.05 and 0.5 atm is applied to extract pure CO.sub.2 from the solids containing CaCO.sub.3 while cooling them by 30-200? C. Said combustion can be carried out directly with air, oxygen enriched air or O.sub.2/CO.sub.2 mixtures when the process is applied to the calcination of a continuous flow of limestone in a moving bed shaft kiln. The process is also applied to calcine CaCO.sub.3 formed in reversible calcium looping processes comprising a carbonation reaction step to form CaCO.sub.3 from CaO.

The present invention relates to a process and apparatus for improving the combustion of a secondary fuel supplied in a first stream in a rotary kiln, wherein the rotary kiln has a burner assembly comprising a main burner and a plurality of feed channels for various media, of which one is designed for the supply of a secondary fuel, in particular in the form of particles or shreds in a stream of compressed air. According to the invention, a tubular oxygen lance for an oxygen-rich gas, in particular, technical grade gaseous oxygen, or an oxygen-rich liquid, in particular, technical grade liquid oxygen, with an angled nozzle at its end, is arranged in or on a feed channel of the burner assembly, whereby the oxygen lance is brought into such a position that the oxygen emerging from a nozzle forms a second stream that strikes a first stream of secondary fuel. The present invention may be considered for new constructions of burner assemblies for rotary kilns, but mainly serves for retrofitting existing burner assemblies in which mostly feed channels are available as required for inserting an oxygen lance in the present invention. Targeted delivery of gaseous or liquid oxygen, or oxygen-enriched gas or liquefied gas to a secondary fuel can significantly improve the combustion process and consequently significantly reduce exhaust emissions, in particular, the emission of carbon monoxide.

The invention concerns: A) An assembly to reduce the emission of CO.sub.2 in a plant for the production of clinkers comprising two calciners and a carbonator arranged between the two calciners, wherein one of the calciners is an integral part of a conventional clinker production system. Thanks to this assembly, the plant can continue to operate in the clinker production process even if the CO.sub.2 capture system which uses the carbonator and the other calciner of the assembly is disconnected due to malfunctions or maintenance characterized in that said carbonator is free of recirculation to both said two calciners. B) The relative plants comprising both the assembly and the actual clinker production plant in which the clinker production plant is of the conventional type existed before and already operational, or said plant is installed simultaneously with the assembly units. C) The clinker production process with reduction of CO.sub.2 emission conducted in the plants B.