System and process for producing cement together with the separation of carbon dioxide

Abstract

The invention relates to a process for producing cement clinker (11) from raw meal (120), the process comprising the following steps: preheating (10) the raw meal (120) to form hot meal (122); separating (20) the hot meal (122) in a cyclone separator (161); and introducing the hot meal (122) via a hot-meal line (163) into an entrained-bed reactor (170); calcining (30) the hot meal (122) to form deacidified raw meal (121) in the entrained-bed reactor (170) as a calciner; separating (40) the deacidified raw meal (122) in a cyclone separator (177) downstream of the entrained-bed reactor (17), as the calciner, in the gas-flow direction; sintering (40) the separated, deacidified raw meal (121) in a rotary kiln (170) to form cement clinker (110). The invention also relates to a system corresponding thereto. According to the invention, the raw meal (120) is preheated (10) to form hot meal (122) in an entrained-bed reactor (160) as the first entrained-bed reactor and the exhaust gases of the rotary kiln (130) are applied (55) to said first entrained-bed reactor (160).

Description

[0001] Plant and process for the production of cement with carbon dioxide capture

[0002] The invention relates to a process for producing cement clinker from raw meal, comprising the following steps: preheating the raw meal to hot meal, separating the hot meal in a cyclone separator and introducing the hot meal via a hot meal line into an entrained flow reactor, calcining the hot meal to deacidified raw meal in the entrained flow reactor as a calciner, separating the deacidified raw meal in a cyclone separator following the entrained flow reactor as a calciner in the gas flow direction, sintering the separated, deacidified raw meal in a rotary kiln to produce cement clinker, and a plant corresponding thereto.

[0003] During the well-known production of cement clinker from a mixture of silicate-containing and carbonate-containing rock flour, the raw meal, carbon dioxide (CO2) is produced from two independent sources. Firstly, carbon dioxide (CO2) is produced during the combustion of fossil fuels and also during the combustion of alternative secondary fuels for the highly endothermic process. Secondly, carbon dioxide (CO2) is produced during the calcination of the carbonate-containing rock flour, in which carbon dioxide (CO2) is formally driven out of the carbonate to obtain burnt lime (CaO) as an intermediate product. Carbon dioxide (CO2) from both sources is usually released into the atmosphere as exhaust gas. Carbon dioxide (CO2) contained in the Earth's atmosphere has been identified as the cause of the currently observed climate change on Earth. Therefore, efforts are currently being made to prevent or at least reduce the release of carbon dioxide (CO2) into the atmosphere.

[0004] The separation of carbon dioxide (CO2) from exhaust gases is a highly endothermic process and requires thermal energy. It therefore makes sense to use the waste heat from the cement process to operate the CO2 separation process. However, the waste heat available during the cement clinker production process is insufficient to capture all of the CO2. Cement production using current methods generates more carbon dioxide (CO2) than can be captured using the waste heat available in the process. One option for obtaining the missing thermal energy is to replace this heat with heat pumps. However, heat pumps require electrical power to operate, and converting this power from heat is very inefficient.Another option for providing the thermal energy required for the capture and storage of carbon dioxide (CO2) is a separate hot gas generator. However, this would incur additional plant costs, emit additional CO2 when operated with fossil fuels, and produce fuel ash as waste. This waste itself poses a disposal problem. Therefore, it would be necessary to design this hot gas generator in such a way that as little problematic ash as possible is produced as waste. The construction and operation of such a plant is, in turn, very costly.

[0005] The object of the invention is therefore to modify a known process for producing cement clinker in such a way that sufficient waste heat is available in the production process. In a conventional process for producing cement clinker, efforts are made to optimize the entire process so that as little or no waste heat as possible is generated, since heat loss is associated with low economic efficiency. According to the present object of the invention, exactly the opposite is desired, namely that the process generates as much waste heat as possible, which can be used to operate a process to separate carbon dioxide (CO2). If the known process for producing cement clinker is modified so that as much waste heat as possible is generated, further process properties can be used which make ash post-treatment superfluous. The proposed process fundamentally changes the requirements for process design.

[0006] While previously the generation of waste heat was avoided as much as possible, the aim now is to generate as much waste heat as is needed to capture CO2 from the exhaust gas. Nevertheless, the production of cement clinker remains the primary goal.

[0007] First of all, it is recognized that it is not possible to operate a known plant for the production of cement clinker using a surplus of fuel and thus a surplus of waste heat, because this would cause the plant to overheat.The solution to the inventive problem consists in modifying the known production process of preheating the raw meal, calcining the preheated raw meal, sintering the raw meal, and subsequent cooling of the sintered cement clinker in such a way that the waste heat generated during cooling and the waste heat in the sintering furnace are not used for endothermic calcination, and the waste heat generated during calcination is not used for preheating. Instead, this waste heat is first used for preheating and only then is the remaining excess heat used for calcination. The remaining thermal energy is then added by burning preferably waste-based secondary fuels for calcination. According to the concept of the invention, the sequence of waste heat utilization during preheating, calcination, and sintering is modified.Only this makes it possible to operate with a high fuel surplus, generating as much waste heat as possible. Specifically, the object of the invention is achieved by preheating a portion of the raw meal in an entrained-flow reactor as the first entrained-flow reactor and subjecting this first entrained-flow reactor to the hot exhaust gases from the rotary kiln. Further advantageous embodiments of the method are specified in the subclaims to claim 1. The method according to the invention can be implemented in a plant according to claim 10. Further advantageous embodiments of the plant are specified in the subclaims to claim 10.

[0008] In order to implement the inventive concept as optimally as possible, it is advantageous to replace the established cyclone heat exchanger with an entrained-flow reactor, with this entrained-flow reactor acting as a preheater. Two requirements then arise for the calcination in the downstream reactor from the gas and waste heat flow direction. The temperature required for the ignition of the fuel must have been transferred to the meal stream in the first entrained-flow reactor, which serves as the heat transfer medium in this second step, so that the fuel can be ignited in an atmosphere consisting of raw meal, air, and oxygen that is now too cold. A very long residence time in the entrained-flow reactor, which acts as a calciner, is necessary to heat the tertiary air, from which heat can optionally be extracted for preheating, to heat the fuel and raw material, and to enable burnout.These requirements can be met by the specialist through appropriate optimized design of the process.

[0009] In addition to the process in reverse of the gas flow direction and the waste heat flow direction, whereby the waste heat from the rotary kiln is first used to preheat a portion of the flour (20-50%) and the remaining heat is used for CO2 capture, the concept of the invention provides further possibilities for generating even more waste heat in the process, namely cooling the cement clinker in a clinker cooler located downstream of the rotary kiln in the direction of material flow and introducing heated cooling air as tertiary air from a cooler head housing of the clinker cooler into a second entrained-flow reactor, which acts as a calciner, via a tertiary air line. The thermal energy in the tertiary air is then used to ignite the fuel during calcination. To further increase the available amount of waste heat, it is possible to extract waste heat from the tertiary air via a heat exchanger, with the heat exchanger connected to the tertiary air line.The tertiary air carries high-calorific heat, which can be used as operating energy in another process for separating carbon dioxide (CO2). This causes the tertiary air to cool significantly. To compensate for this heat loss, it is now possible to use significantly more fuel in the entrained-flow reactor, which acts as a calciner.

[0010] To utilize even more waste heat from the cement clinker production process, it is possible to extract waste heat from heated cooling air as exhaust air via a heat exchanger connected to a gas line for discharging exhaust air from the cooler. This waste heat is low-calorific heat and is suitable for drying fuels or heating catalysts used in the chemical conversion of carbon dioxide (CO2). Extracting the waste heat from the cooler does not require additional compensation for the thermal energy in the existing cement clinker production process.

[0011] The thermal energy still present in the exhaust gas of the rotary kiln after preheating of the raw meal can be tapped directly by extracting waste heat from the heated exhaust gas separated by a cyclone separator from the first entrained-flow reactor, which acts as a preheater, via a heat exchanger that is connected to a gas line for discharging the exhaust gas from this first entrained-flow reactor.

[0012] In order to utilize even more waste heat from the cement clinker production process, it is possible to extract waste heat from heated exhaust gas separated by a cyclone separator from the entrained-flow reactor acting as a calciner via a heat exchanger that is connected to a gas line for discharging the exhaust gas from the second entrained-flow reactor.

[0013] The process can generate even more waste heat by using an additional entrained-flow reactor, which also acts as a calciner. This third entrained-flow reactor is connected downstream of the second entrained-flow reactor, which also acts as a calciner, in the gas flow direction. It is then possible to extract waste heat from the heated exhaust gas separated by a cyclone separator from the entrained-flow reactor, which acts as a calciner, via a heat exchanger connected to a gas line for discharging the exhaust gas from the second entrained-flow reactor.

[0014] The invention is explained in more detail with reference to the following figures. They show:

[0015] Fig. 1 shows a plant for implementing the method according to the invention in a first embodiment,

[0016] Fig. 2 shows a plant for implementing the method according to the invention in a second embodiment,

[0017] Fig. 3 is a flowchart of the method according to the invention in a first embodiment,

[0018] Fig. 4 is a flowchart of the method according to the invention in a second embodiment.

[0019] Figure 1 outlines a plant 100 for implementing the method according to the invention in a first embodiment. This plant 100 is primarily designed for the production of cement clinker 110 from raw meal 120, but unlike known plants, it is intended to generate as much waste heat as possible. Like other known plants, this plant 100 has at least one rotary kiln 130 for sintering deacidified raw meal 121 into cement clinker 110. The rotary kiln is fired by a burner, which is itself supplied with primary fuel 200 and primary air 202. Downstream of the rotary kiln 130 in the material flow direction is at least one clinker cooler 140 for cooling the cement clinker 110, wherein the clinker cooler 140 shown here has a tertiary air line 150 for removing cooling air 147 heated in the cooler head housing 149 of the clinker cooler 140 as tertiary air 151.Atmospheric cooling air 147 is blown into the clinker cooler 140. This air flows from below through the cement clinker 110, thereby cooling the hot cement clinker 110, which has a temperature of approximately 1,400°C upon discharge from the rotary kiln 130. The cooling air 147, which heats up in the process, reaches a temperature of nearly 1,250°C near the rotary kiln head, i.e., the part of the rotary kiln 130 that extends into the cooler 140. This hot cooling air 151, which is generated in the cooler head housing 149, is partially conducted into the system 100 through a tertiary air line 150 to recuperate the heat contained in the hot cooling air. It is possible to extract heat from the tertiary air 150, which would otherwise be used for recuperation, via a heat exchanger 155 as waste heat Q. Another part of the hot cooling air generated there is fed into the rotary kiln 130 as secondary air 203.Cooling air 147, which flows into cooler 140 further away from the rotary kiln head, encounters already cooled cement clinker 110 and only takes on the lower temperature of the cement clinker 110 located there. At the end of clinker cooler 140, the heated cooling air has a temperature of only between 200°C and 300°C.

[0020] Downstream of the rotary kiln 130 in the gas flow direction, which in the plant 100 is largely opposite to the material flow direction, is a first entrained-flow reactor 160 acting as a heat exchanger, in which raw meal 120 is preheated by the hot exhaust gases of the rotary kiln 130 to form hot meal 122. Following this entrained-flow reactor 160 in the gas flow direction is a first cyclone separator 161 for separating the hot meal 122. The cyclone separator 161 separates the hot meal 122 from the now cooled exhaust gases of the rotary kiln 130. A first hot meal line 163 directs the hot meal 122 into a second entrained-flow reactor 170 acting as a calciner, which is itself connected to the tertiary air line 150 and is fed with tertiary air 151 from it.A meal line 179 conducts deacidified raw meal 121 originating from the second entrained-flow reactor 170, which acts as a calciner, into the rotary kiln 130. This deacidified raw meal 121 is separated from the process gas in the entrained-flow reactor 170 by a cyclone separator 177. This plant 100 has several locations where heat can be extracted from an exhaust gas or a process gas. The extracted heat, which is missing in the cement clinker production process, can then be compensated for by using more fuel in the rest of the plant. A first location where ample waste heat Q can be extracted is the gas line 168. This discharges an exhaust gas from the aforementioned cyclone separator 161 and also contains valuable waste heat, which is extracted via a heat exchanger 165 connected to this gas line 168.In the diagram, heat Q is represented by a dot above it, indicating that a heat flow is involved. To extract the exhaust gas from the cyclone separator 161, a compressor 166 can be arranged downstream of the heat exchanger 165. This compressor supports the gas flow from the rotary kiln 130 to the heat exchanger 165 by extracting cooled exhaust gas 169, which contains carbon dioxide (CO2).

[0021] The second entrained-flow reactor 170, which acts as a calciner, is designed for a residence time of 4 seconds to 8 seconds, thus having a longer residence time than typically exhibited by known calciners. This longer residence time is intended to ensure that the secondary fuel 201, which is fed into the entrained-flow reactor 170 via a fuel feed 171, reliably ignites and burns out. Since the supply air to the entrained-flow reactor 170 consists of cooled tertiary air 150, the ignition tendency of the secondary fuel 201 is somewhat reduced. To still achieve ignition, the secondary fuel is fed together with the hot meal 122 into the entrained-flow reactor acting as a calciner, with the hot meal providing the necessary ignition energy.The entrained-flow reactor 170, which acts as a calciner, receives not only hot meal 122 from the first entrained-flow reactor 160, which acts as a heat exchanger, but also cold raw meal, which is fed into the entrained-flow reactor via a raw meal feed 172. By feeding cold raw meal, it is possible to control the temperature in the entrained-flow reactor 170. The hot meal 122, which is calcined in the entrained-flow reactor 170 to deacidified raw meal 121, is separated by a cyclone separator 177 and, as previously mentioned, is conveyed to the rotary kiln via a meal line 179. Exhaust gas 189, which is produced in the entrained flow reactor 170 and separated via the cyclone separator 177, leaves the plant 100 via the gas line 188. However, waste heat Q is first extracted from this exhaust gas 189 via a heat exchanger 185 in the gas line 188 before it leaves the plant 100 as cooled exhaust gas 189.

[0022] Exhaust gas from the second entrained-flow reactor 170, which acts as a calciner, passes through a burnout chamber 175 to safely burn off the fuel. The meal / gas suspension produced in the entrained-flow reactor 170 then travels via the downstream branch 176 into the cyclone separator 177.

[0023] Figure 2 shows a plant 200 for implementing the process according to the invention in a first embodiment. This plant differs from plant 100 in Figure 1 by an additional, third entrained-flow reactor 180. Following the second entrained-flow reactor 170, which acts as a calciner, in the gas flow direction is this third entrained-flow reactor 180, which has a fuel feed 181 for secondary fuel 201 and a raw meal feed 182 for raw meal 120. This third entrained-flow reactor 180 also functions as a calciner, with a meal line 183 conveying deacidified raw meal 121 originating from the third entrained-flow reactor 180, which has been separated via a cyclone separator 187, into the rotary kiln 130. The exhaust gas from the second entrained-flow reactor 170, which acts as a calciner, is fed with an oxygen content of 10-15% into this third entrained-flow reactor 180, which also acts as a calciner.There, additional secondary fuel 201 is added together with a portion of the raw meal 120. The raw meal 120 also serves to control the temperature in this entrained-flow reactor 180. After the secondary fuel 201 is ignited, the remaining raw meal 120 is added, heated, and calcined. This third entrained-flow reactor 180, which also acts as a calciner, is also designed for a residence time of 4 to 8 seconds and has a burnout chamber 185 at its deflection to support complete burnout of the secondary fuel 201. For the remaining system components of the system 200, reference is made to the description of Figure 1.

[0024] Figure 3 shows a flow diagram of the method according to the invention in a first embodiment. The method for producing cement clinker 110 from raw meal 120 comprises the following steps, beginning with the provision of raw meal, a mixture of silicate-containing rock and carbonate-containing rock: Preheating 10 of the raw meal 120 to hot meal (122), followed by separation 20 of the hot meal 122 in a cyclone separator 161 and introduction of the hot meal 122 via a hot meal line 163 into an entrained-flow reactor 170. This is followed by calcination 30 of the hot meal 122 to deacidified raw meal 121 in the entrained-flow reactor 170, which acts as a calciner. After deacidification, the deacidified raw meal 121 is separated 40 in a cyclone separator 177 following the entrained-flow reactor 170 acting as a calciner in the gas flow direction. From there, the separated, deacidified raw meal 121 is sintered 50 in a rotary kiln 130 to produce cement clinker 110.

[0025] According to the idea of ​​the invention, the following procedure is provided, namely preheating 10 of the raw meal 120 to hot meal 122 in an entrained-flow reactor 160 as the first entrained-flow reactor and supplying 55 this first entrained-flow reactor 160 with the exhaust gases from the rotary kiln 130. At this point, the procedure differs from known processes for producing cement clinker 110 in that the exhaust gas from the rotary kiln 130 is not used for calcination, but for preheating 10 and the preheating takes place in an entrained-flow reactor 160 in order to be able to withstand the high exhaust gas temperatures of the rotary kiln 130.

[0026] After sintering, a process step known per se can follow, namely cooling 60 of the cement clinker 110 in a clinker cooler 140, which is arranged downstream of the rotary kiln 130 in the direction of material flow, and then introducing 65 heated cooling air as tertiary air 151 from a cooler head housing 149 of the clinker cooler 140 into the second entrained flow reactor 170 via a tertiary air line 150.

[0027] Four special locations are suitable for extracting waste heat from the process.

[0028] A first point of withdrawal for waste heat Q is located in the gas path after the separator 161 of the first entrained-flow reactor 160, which is used to preheat the raw meal 120, in process step 20 'Separation'.

[0029] A second waste heat removal point Q is located in the gas path after the separator 177 of the second entrained flow reactor 170, which is used for calcining raw meal / hot meal, in process step 40 "Separation".

[0030] A third point of consumption for waste heat Q is located in the gas path after cooling in the clinker cooler 140 in process step 60 "Cooling".

[0031] A fourth point of consumption for waste heat Q is located in the gas path of the tertiary air 150, namely in the tertiary air line in process step 65 "Discharge".

[0032] The waste heat Q, which can be extracted at the aforementioned points of consumption, can be used to operate a further process for the separation of carbon dioxide (CO2), which is inevitably produced during the production of cement clinker 110.

[0033] Finally, Figure 4 shows a flow diagram of the process according to the invention in a second embodiment. The process according to this flow diagram differs from the process according to the flow diagram in Figure 3 by a further process step, calcination 70. This is provided after the first calcination step 30 and separation step 40. This second calcination step increases the capacity of the second entrained-flow reactor, which acts as a calciner. This is because the second entrained-flow reactor 170, which acts as a calciner, is operated at a reduced temperature, the tertiary air feeding it. LIST OF REFERENCE SYMBOLS

[0034] Preheating 140 clinker cooler

[0035] Separation 145 Heat exchanger

[0036] Extraction 146 exhaust air

[0037] Calcining 147 Cooling air

[0038] Separation 148 Gas line

[0039] Remove 149 radiator head housing

[0040] Sintering 150 tertiary air line

[0041] Cooling 151 Tertiary air

[0042] Introduce 155 heat exchanger

[0043] Removal 160 first entrained flow reactor

[0044] Removal 161 cyclone separator

[0045] Calcining 162 Raw meal feed

[0046] Removal 163 hot flour line

[0047] System 165 heat exchanger

[0048] Cement clinker 166 compressor

[0049] Raw meal 168 Gas line deacidified raw meal 169 Exhaust gas

[0050] Hot meal 170 second entrained flow reactor

[0051] Rotary kiln 171 fuel feed

[0052] Inlet chamber 172 Raw meal feed Burnout chamber 188 Gas line descending branch 189 Exhaust gas cyclone separator 186 Compressor meal line 200 Primary fuel third entrained flow reactor 201 Secondary fuel fuel feed 202 Primary air raw meal feed 203 Secondary air meal line Q waste heat

[0053] Heat exchanger B fuel descending branch

[0054] cyclone separator

Claims

PATENT CLAIMS 1. A process for producing cement clinker (110) from raw meal (120) comprising the following steps: Preheating (10) of the raw flour (120) to hot flour (122), Separating (20) the hot meal (122) in a cyclone separator (161) and introducing the hot meal (122) via a hot meal line (163) into an entrained flow reactor (170), Calcining (30) the hot meal (122) to deacidified raw meal (121) in the entrained flow reactor (170) as a calciner, Separating (40) the deacidified raw meal (121) in a cyclone separator (177) following the entrained flow reactor (170) as a calciner in the gas flow direction, Sintering (50) of the separated, deacidified raw meal (121) in a rotary kiln (130) to cement clinker (110), characterized by Preheating (10) of the raw meal (120) to hot meal (122) in an entrained flow reactor (160) as the first entrained flow reactor, Applying (55) this first entrained flow reactor (160) with the exhaust gases from the rotary kiln (130).

2. Method according to claim 1, characterized by Cooling (60) of the cement clinker (110) in a clinker cooler (140) which is arranged downstream of the rotary kiln (130) in the direction of material flow, Introducing (65) heated cooling air as tertiary air (151) from a cooler head housing (149) of the clinker cooler (140) into the second entrained flow reactor (170) via a tertiary air line (150).

3. Method according to claim 2, characterized by Extraction (66) of waste heat (Q) from the tertiary air (151) via a heat exchanger (155) which is connected to the tertiary air line (150).

4. Method according to claim 2 or 3, characterized by Extraction (67) of waste heat (Q) from heated cooling air (147) as exhaust air (146) via a heat exchanger (145) which is connected to a gas line (148) for discharging exhaust air (146) from the cooler (140).

5. Method according to one of claims 2 to 4, characterized by Extracting (25) waste heat (Q) from heated exhaust gas (169) separated by a cyclone separator (161) from the first entrained-flow reactor (160) via a heat exchanger (165) which is connected to a gas line (168) for discharging the exhaust gas (169) from the first entrained-flow reactor (160).

6. Method according to one of claims 2 to 5, characterized by Extraction (45) of waste heat (Q) from heated exhaust gas (189) separated via a cyclone separator (177) from the entrained-flow reactor (170) acting as a calciner via a heat exchanger (185) which is connected to a gas line (188) for discharging the exhaust gas (189) from the second entrained-flow reactor (170).

7. Method according to one of claims 1 to 5, characterized by Connecting a third entrained-flow reactor (180) as a further calciner in the gas flow direction behind the entrained-flow reactor (170) acting as a calciner, Calcining (70) of further raw meal (120) in the third entrained flow reactor (180) to deacidified raw meal (121), Separation (80) of the raw meal (121) deacidified in the third entrained flow reactor (180) in a cyclone separator (187), Introducing deacidified raw meal (121) separated from the cyclone separator (187) into the rotary kiln (130).

8. Method according to claim 7, characterized by Extracting (85) waste heat (Q) from heated exhaust gas (189) separated by a cyclone separator (187) from the third entrained-flow reactor (180) via a heat exchanger (185) which is connected to a gas line (188) for discharging the exhaust gas (189) from the third entrained-flow reactor (180).

9. Method according to one of the claims from claims 3 to 6 and 8, characterized by Using the extracted waste heat (Q) to operate a further process for separating and / or depositing carbon dioxide (CO2) from the exhaust gases produced in the process according to one of claims 1 to 8.

0. Plant (100) for producing cement clinker (110) from raw meal (120), according to the method according to claims 1 to 9, comprising at least one rotary kiln (130) for sintering deacidified raw meal (121) to cement clinker (110), at least one clinker cooler (140) for cooling the cement clinker (110), wherein the clinker cooler (140) is arranged downstream of the rotary kiln (130) in the material flow direction, at least one tertiary air line (150) for removing cooling air (147) heated in the cooler head housing (149) of the clinker cooler (140) as tertiary air (151), characterized in that a first entrained flow reactor (160) is arranged downstream of the rotary kiln (130) in the gas flow direction as a heat exchanger, in which raw meal (120) is sintered to hot meal (122) is preheated, which in turn is followed by a first cyclone separator (161) in the gas flow direction for separating the hot meal (122), wherein a first hot meal line (163) guides the hot meal (122) into a second entrained flow reactor (170) as a calciner,which is itself connected to the tertiary air line (150) and is fed therefrom with tertiary air (151), and wherein a flour line (179) conveys deacidified raw meal (121) originating from the second entrained flow reactor (170) acting as a calciner into the rotary kiln (130).

11. Plant according to claim 10, characterized in that the second entrained flow reactor (170) acting as a calciner has a fuel feed (171) for secondary fuel (201).

12. Plant according to claim 10 or 11, characterized in that the second entrained flow reactor (170) acting as a calciner has a raw meal feed (172).

13. Plant according to one of claims 10 to 12, characterized in that the second entrained-flow reactor (170) acting as a calciner is followed in the gas flow direction by a third entrained-flow reactor (180) which has a fuel feed (181) for secondary fuel (201) and a raw meal feed (182) for raw meal (120), wherein a meal line (183) guides deacidified raw meal (121) originating from the third entrained-flow reactor (180) into the rotary kiln (130).

14. Installation according to one of claims 10 to 13, characterized in that that a heat exchanger (145, 165) is arranged downstream in a gas line (148, 168) in the gas flow direction in the gas path of the clinker cooler (140) and / or the first entrained flow reactor (160), via which heat (Q) is separated for the operation of a further plant for the separation of carbon dioxide (CO2).

15. Plant according to one of claims 10 to 14, characterized in that a heat exchanger (155) is connected in the tertiary air line (150), via which heat (Q) is separated for the operation of a further plant for the separation of carbon dioxide (CO2).

16. Plant according to claim 13, characterized in that a heat exchanger (185) is connected in a gas line (188) in the gas flow direction in the gas path of the third entrained flow reactor (180), via which heat (Q) is separated for the operation of a further plant for the separation of carbon dioxide (CO2).

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