Material cooler
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- THYSSENKRUPP POLYSIUS GMBH
- Filing Date
- 2024-06-04
- Publication Date
- 2026-04-15
AI Technical Summary
In material coolers used in the oxyfuel process, especially for producing clinker, there is a challenge in preventing the ingress of secondary air and nitrogen into the oxygen-rich atmosphere, leading to mixing and loss of valuable oxygen, and existing static devices like baffling plates show wear and are ineffective within the material bed.
A material cooler design with a second cooling zone that supplies water vapor at over 100°C from below the material layer to create a water vapor barrier, preventing condensation and unwanted reactions, and additional zones for operation in oxygen-rich or carbon dioxide-enriched atmospheres, along with mechanical gas separation devices, to maintain a gas barrier and reduce nitrogen ingress.
This design effectively prevents the entry of secondary air, maintains a clean gas atmosphere, reduces wear, and facilitates easier carbon dioxide separation and storage, enhancing climate neutrality by minimizing nitrogen and oxygen mixing and maintaining a stable gas environment.
Smart Images
Figure EP2024065278_12122024_PF_FP_ABST
Abstract
Description
[0001] Material cooler
[0002] The invention relates to a material cooler with sealing of the oxygen-exposed warmer part against the ambient air in the colder part of the material cooler.
[0003] Plants, for example, for clinker production, are now operated using the so-called oxyfuel process, ideally using pure oxygen. This means that the gas at the end of the process is ideally carbon dioxide (with water vapor), which can be easily separated and thus does not reduce the carbon dioxide concentration at the inlet of a downstream carbon dioxide separation device. This allows the carbon dioxide to be easily separated, thus avoiding emissions. In particular, this eliminates the need for complex separation, particularly of nitrogen. Therefore, any source of secondary air, i.e., the possibility of ambient air entering the system, must be avoided as far as possible.
[0004] A common separation point between the oxygen-containing area and the ambient air is usually found in the material cooler, where cooling takes place at least at the end with ambient air.
[0005] From DE 10 2006 026 234 A1 a device and a method for cooling bulk material are known.
[0006] WO 2022 248 384 A1 discloses a method and a device for producing cement clinker.
[0007] From US 11 621 168 B1 a method and a device for doping semiconductor materials is known.
[0008] US Pat. No. 8,850,831 B2 discloses a method for cooling granular solid material. DE 21 58 317 A1 discloses a firing device for firing ore pellets and similar bodies.
[0009] From US 5 775 891 A a grate cooler for combustion material and a method therefor are known.
[0010] From DE 24 04 086 A1 a method and a device for cooling a granular material is known.
[0011] To prevent unwanted mixing and thus the ingress of false air, separating or baffles are typically used in the material cooler to minimize gas flows between the different areas. These measures take effect above the material bed and thus reduce mixing. However, these measures have no effect within the material bed, where gas mixing can occur. However, this still leads to mixing and thus to the loss of valuable oxygen and the ingress of nitrogen into the interior. Furthermore, such static devices are subject to wear.
[0012] The object of the invention is to minimize the entry of secondary air into the system via the material cooler.
[0013] This object is achieved by the material cooler having the features specified in claim 1 and by the method having the features specified in claim 10. Advantageous further developments emerge from the subclaims, the following description, and the drawings.
[0014] The material cooler according to the invention serves to cool a thermally treated material, in particular a bulk material, for example clinker. The actual thermal treatment process is preferably carried out according to the oxyfuel process, i.e. in an oxygen-rich atmosphere. The material cooler has a support surface for the material to be cooled. The material to be cooled moves along the support surface through the material cooler. This can occur actively via a conveyor or passively, for example via an inclined arrangement. The material cooler has an application side for introducing hot material onto the support surface and a discharge side for discharging the cooled material. The material cooler has at least a first cooling zone and a second cooling zone. The first cooling zone is adjacent to the discharge side. The cooled material is thus discharged from the first cooling zone. The first cooling zone has a gas supply.For example, ambient air is preferably supplied via the gas supply to cool the material so that it can be handled after removal from the material cooler. A gas, for example, from a circuit, can also be supplied via the gas supply. The gas supplied via the gas supply usually contains a disruptive gas component, particularly nitrogen. The second cooling zone is adjacent to the first cooling zone. Thus, the second cooling zone is located upstream of the first cooling zone along the material flow.
[0015] According to the invention, the second cooling zone has a first water supply for water at a temperature of more than 100°C. The first water supply is arranged below the support surface or in the material layer arranged on the support surface. This serves to create a water vapor barrier layer in the material layer. The first water supply can be designed for liquid, hot water under pressure or for water vapor. A supply above 100°C is effective in preventing condensation in the material. The materials to be cooled, such as clinker, can react with water, so humidification must be avoided. This is necessary, for example in the case of clinker, to prevent a subsequent and unwanted reaction during storage of the product. The water is preferably supplied between 100 and 200°C. Here, the optimum balance between utilizing the thermal energy and avoiding condensation must be selected.Direct cooling of the material layer from above, for example by spraying water, is known. The disadvantage, however, is that the gaseous water only forms above the material layer, which is then cooled by the flow from below. Thus, water sprayed from above only has a similar effect to baffles or guide plates. Furthermore, there is an increased risk of strong local cooling of the material, causing water to be absorbed and thus an unwanted reaction during storage. The key to the invention, however, is the application of the water below or within the material layer, thereby achieving a barrier effect in the material layer as well, not just above it.
[0016] A key feature is the water supply from below. Application from above, for example, by spraying, is also known. In all these cases, however, a gas layer always remains within the material, which is not taken up by water vapor. By supplying the water from below, the gas flows through the material layer, thus creating an efficient gas barrier in this area as well, even within the material.
[0017] The type of first water supply, from below the support surface or in the material layer arranged on the support surface, directly results from the device's features that a water vapor barrier layer is created within the material layer during operation. Furthermore, the first water supply must be suitable for conveying steam or pressurized water at temperatures exceeding 100°C. With steam, the flow volume is significantly larger, while with liquid water, the pressure is significantly higher. Furthermore, condensation in the first water supply must be prevented to prevent liquid water at temperatures below 100°C from being pumped into the material layer.
[0018] The effect created in the process therefore results directly from the structural measures of the material cooler.
[0019] The advantage of using steam is that water can be removed from an exhaust stream particularly easily through condensation. This makes carbon dioxide capture for use and storage, and thus for achieving overall climate neutrality, easier to implement.
[0020] By introducing the water vapor from below and creating a water vapor barrier layer in the material layer, a water vapor barrier layer is also created above the material layer, allowing a separation to occur here as well, which can be further supported, for example, by separating plates and the like, as is known from the prior art. What is essential to the invention is that, in addition to this known water vapor barrier layer above the material layer, a water vapor barrier layer is automatically created in the material layer by the device, thus reliably preventing unwanted air from entering through the material layer.
[0021] In a further embodiment of the invention, the material cooler has a third cooling zone. The third cooling zone is adjacent to the second cooling zone. The third cooling zone is designed for operation with enriched oxygen with a proportion of more than 50 vol. %, preferably more than 90 vol. %, oxygen, i.e. for the so-called oxyfuel process. This means that the material cooler is equipped for such operation, as is familiar to those skilled in the art. For example, this concerns the selection of materials, which must be resistant to an oxygen-rich atmosphere, as is familiar to those skilled in the art. Furthermore, it also concerns sealing against the environment, which is also familiar to those skilled in the art, in order to prevent infiltration of air and thus the unwanted penetration of nitrogen. The device must therefore be designed, within the framework of technical considerations, to be operated with such an atmosphere.
[0022] Alternatively, the oxygen-enriched atmosphere can also be created in a device adjacent to the material cooler and thus to the second cooling zone, such as a furnace head. In this case, the seal is created directly on the application side of the material cooler.
[0023] In a further embodiment of the invention, the second zone extends over at least 2%, preferably at least 3%, of the total length of the material cooler.
[0024] In a further embodiment of the invention, the second zone extends over at most 50%, preferably at most 35%, further preferably at most 20%, further preferably at most 10%, of the total length of the material cooler.
[0025] In a further embodiment of the invention, the material cooler has a third cooling zone. The third cooling zone is adjacent to the second cooling zone. The third cooling zone is designed for operation with a mixture of carbon dioxide and oxygen, where the sum of oxygen and carbon dioxide is more than 80 vol.%. This also corresponds to the oxyfuel process, whereby additional carbon dioxide (usually from the exhaust gas) is recirculated. This increases the gas flow to replace the nitrogen missing in pure oxygen and thus adjust the carrying capacity of the gas flow to be comparable with conventional processes. For example, the ratio of oxygen to carbon dioxide can therefore be selected to be 1:5, analogous to the oxygen content in the air, taking other gas components into account. This means that the material cooler is equipped for this type of operation, as is familiar to those skilled in the art.For example, this concerns the selection of materials, which, as is familiar to those skilled in the art, must be resistant to an oxygen-rich and / or carbon dioxide-rich atmosphere. It also concerns sealing against the environment, as is familiar to those skilled in the art, to prevent leakage of air and thus the unwanted ingress of nitrogen. Therefore, the device must be designed, within the scope of technical considerations, to operate in such an atmosphere.
[0026] In a further embodiment of the invention, the material cooler has a fourth cooling zone. The fourth cooling zone is adjacent to the second cooling zone. The fourth cooling zone has a carbon dioxide supply. In particular, the carbon dioxide can be supplied to a calciner, for example, via a carbon dioxide outlet and a tertiary air line. Additionally or alternatively, the carbon dioxide outlet can be connected to the carbon dioxide supply, i.e. the carbon dioxide can be recirculated. The carbon dioxide therefore does not have to be pure carbon dioxide, but particularly in the case of recirculated carbon dioxide, it can contain other substances. The aim is to achieve a double barrier layer, one consisting of water vapor and the other of (recirculated) carbon dioxide. Accordingly, the device is designed to be able to handle these atmospheres or to be stable in these atmospheres.
[0027] In a further embodiment of the invention, the material cooler has a fifth cooling zone. The fifth cooling zone is adjacent to the fourth cooling zone. The fifth cooling zone has a second water supply for water at more than 100°C. The second water supply is arranged below the support surface or in the material layer arranged on the support surface to create a water vapor barrier in the material layer. The second water supply can be designed for liquid water under pressure or for water vapor. A supply above 100°C is effective to prevent condensation in the material. This is necessary, for example, in the case of clinker, to prevent a subsequent and unwanted reaction during storage of the product. The water is preferably supplied between 200 and 400°C. Since another cooling zone follows, water at a significantly higher temperature can be used here.The above statement also applies here. The second water vapor barrier layer allows secondary and tertiary air, in particular, to be kept comparatively clean. Here, too, the device's spatial features are designed to create and support these different zones and thus different atmospheres.
[0028] In a further embodiment of the invention, the material cooler has a seventh cooling zone. The seventh cooling zone is adjacent to the fourth cooling zone. The seventh cooling zone is designed for operation with enriched oxygen with an oxygen content of more than 50 vol. %, preferably more than 90 vol. This means that the material cooler is equipped for such operation, as is familiar to those skilled in the art. For example, this concerns the selection of materials, which must be resistant to an oxygen-rich atmosphere, as is familiar to those skilled in the art. Furthermore, it also concerns sealing against the environment, which is also familiar to those skilled in the art, in order to prevent infiltration of air and thus the unwanted penetration of nitrogen. The device must therefore be designed, within the framework of specialist considerations, to be operated with such an atmosphere.
[0029] In a further embodiment of the invention, the material cooler has a sixth cooling zone. The sixth cooling zone is adjacent to the fifth cooling zone. The sixth cooling zone is designed for operation with enriched oxygen with an oxygen content of more than 50 vol. %, preferably more than 90 vol. This means that the material cooler is equipped for such operation, as is familiar to those skilled in the art. For example, this concerns the selection of materials, which must be resistant to an oxygen-rich atmosphere, as is familiar to those skilled in the art. Furthermore, it also concerns sealing against the environment, which is also familiar to those skilled in the art, in order to prevent infiltration of air and thus the unwanted penetration of nitrogen. The device must therefore be designed, within the framework of specialist considerations, to be operated with such an atmosphere.
[0030] In a further embodiment of the invention, the third cooling zone has a gas outlet. The gas outlet is connected to the carbon dioxide supply and / or a calciner, in particular via a tertiary air line.
[0031] In a further embodiment of the invention, a first mechanical gas separation device is arranged between the first cooling zone and the second cooling zone. The first mechanical gas separation device is preferably spaced sufficiently from the material on the support surface to prevent wear. Additional mechanical gas separation devices can also be arranged analogously between further cooling zones.
[0032] Of course, it is possible to combine the embodiments according to the invention with prior art separating or baffle plates. This, of course, further reduces unwanted mixing.
[0033] In a further aspect, the invention relates to a method for operating a material cooler according to the invention. An application atmosphere is present on the application side, and a discharge atmosphere is present on the discharge side. The application atmosphere differs from the discharge atmosphere. The discharge atmosphere is preferably ambient air, or is formed from ambient air and preferably differs from the ambient air only in terms of humidity and, if appropriate, dust. The application atmosphere preferably has a reduced nitrogen content compared to the discharge atmosphere. The application atmosphere and the discharge atmosphere are separated by a water vapor barrier layer in the material to be cooled in the second cooling zone.Unlike nitrogen, water vapor is very easy to separate from carbon dioxide, so that the technical and energy expenditure for carbon dioxide purification can be dramatically reduced for subsequent sequestration of the carbon dioxide and thus for preventing its release into the environment, which is necessary for climate neutrality. At the same time, this also prevents the unwanted release of carbon dioxide. In a further embodiment of the invention, the application atmosphere has a higher oxygen content and a lower nitrogen content than the discharge atmosphere.
[0034] In a further embodiment of the invention, the second cooling zone is non-condensing, i.e., at a temperature level above 100 °C at atmospheric pressure or, in accordance with the vapor pressure curve, at other pressures. As a result, the water remains as water vapor in the gas phase and does not condense on the material. This reliably prevents moisture buildup and thus setting during storage.
[0035] All features described for the device are of course also applicable to the method in an analogous manner.
[0036] The material cooler according to the invention is explained in more detail below using an embodiment shown in the drawings.
[0037] Fig. 1 first example
[0038] Fig. 2 second example
[0039] Fig. 3 third example
[0040] Fig. 4 fourth example
[0041] Fig. 5 fifth example
[0042] Fig. 6 sixth example
[0043] A first example is shown in Fig. 1. It is, for example, a plant for producing clinker from limestone. The plant has a preheater 10, a calciner 20, a rotary kiln 30, and a material cooler 40 according to the invention, wherein the material flow from the preheater 10 is guided via the calciner 20 and the rotary kiln 30 into the material cooler 40. The gas flow goes from the rotary kiln 30 via the calciner 20 into the preheater. The rotary kiln 30, calciner 20, and preheater 10 are designed for operation according to the oxyfuel process, i.e., with (technically) pure oxygen, and are operated accordingly. The material cooler has a first cooling zone 41, which is supplied with cool ambient air by a gas supply 51 and thus cools the material, the clinker, to near ambient temperature.In order to separate the oxygen-rich area from the ambient air, the material cooler has a second cooling zone 42, into which pressurized water at, for example, 150 °C is fed from below via a first water supply 52, thereby creating a safe, simple and wear-free separation between the oxygen-rich area and the ambient air.
[0044] In this respect, all examples discussed below are the same.
[0045] The first example features a direct oxygen supply to the rotary kiln 30, for example, via the kiln head. Since combustion in (technically) pure oxygen is very hot, preheating of the oxygen is unnecessary.
[0046] Fig. 2 shows a second example where the oxygen is not fed directly into the rotary kiln 30, as in the first example, but is first fed via an oxygen supply 53 into a third cooling zone 43, where it is preheated and then fed from the third cooling zone 43 into the rotary kiln. The third cooling zone 43 is arranged directly adjacent to the second cooling zone 42.
[0047] Fig. 3 shows a third example in which a fourth cooling zone 44 is arranged adjacent to the second cooling zone 42. Carbon dioxide is supplied to the fourth cooling zone 44 via a carbon dioxide supply 54. In the third example, as in the first example, the oxygen is also supplied directly to the rotary kiln 30.
[0048] The fourth example shown in Fig. 4 differs from the third example in that a fifth cooling zone 45 with a second water supply 55 is arranged adjacent to the fourth cooling zone 44. This prevents the carbon dioxide from the fourth cooling zone 44 from entering the rotary kiln 30. Instead, the carbon dioxide is fed directly to the calciner 20 via a tertiary air line in order to generate a larger volume flow there and thus increase the load-bearing capacity for the material in the gas stream. The fifth example shown in Fig. 5 differs from the third example in that a seventh cooling zone 47 is arranged adjacent to the fourth cooling zone 44, with (technically) pure oxygen being supplied to the seventh cooling zone 47 via an oxygen supply 57, where it is preheated and then fed to the rotary kiln 30.The carbon dioxide from the fourth cooling zone 44 is fed to the calciner 20 via a tertiary air line, as in the fourth example.
[0049] Fig. 6 shows a sixth example, which differs from the fourth example in that the material cooler 40 has a sixth cooling zone 46 adjacent to the fifth cooling zone 45, wherein (technically) pure oxygen is supplied to the sixth cooling zone 46 via an oxygen supply 56, preheated there and then supplied to the rotary kiln 30.
[0050] Reference symbol
[0051] 10 preheaters
[0052] 20 Calciners
[0053] 30 rotary kilns
[0054] 40 material coolers
[0055] 41 first cooling zone
[0056] 42 second cooling zone
[0057] 43 third cooling zone
[0058] 44 fourth cooling zone
[0059] 45 fifth cooling zone
[0060] 46 sixth cooling zone
[0061] 47 seventh cooling zone
[0062] 51 Gas supply
[0063] 52 first water supply
[0064] 53 Oxygen supply
[0065] 54 Carbon dioxide supply
[0066] 55 second water supply
[0067] 56 Oxygen supply
[0068] 57 Oxygen supply
Claims
Patent claims 1 . Material cooler (40), wherein the material cooler (40) has a support surface for the material to be cooled, wherein the material cooler (40) has an application side for introducing hot material onto the support surface and a discharge side for discharging the cooled material, wherein the material cooler (40) has at least a first cooling zone (41) and a second cooling zone (42), wherein the first cooling zone (41) is adjacent to the discharge side, wherein the first cooling zone (41) has a gas supply (51), wherein the second cooling zone (42) is adjacent to the first cooling zone (41), characterized in that the second cooling zone (42) has a first water supply (52) for water at more than 100 °C, wherein the first water supply (52) is arranged below the support surface or in the material layer arranged on the support surface for producing a water vapor barrier layer in the material layer.
2. Material cooler (40) according to claim 1, characterized in that the material cooler (40) has a third cooling zone (43), wherein the third cooling zone (43) is adjacent to the second cooling zone (42), wherein the third cooling zone (43) is designed for operation with enriched oxygen with a proportion of more than 50 vol.%, preferably more than 90 vol.%, of oxygen.
3. Material cooler (40) according to claim 1, characterized in that the material cooler (40) has a third cooling zone (43), wherein the third cooling zone (43) is adjacent to the second cooling zone (42), wherein the third cooling zone (43) is designed for operation with a mixture of carbon dioxide and oxygen, the sum of oxygen and carbon dioxide being more than 80 vol.%.
4. Material cooler (40) according to claim 1, characterized in that the material cooler (40) has a fourth cooling zone (44), wherein the fourth cooling zone (44) is adjacent to the second cooling zone (42), wherein the fourth cooling zone (44) has a carbon dioxide supply (54).
5. Material cooler (40) according to claim 4, characterized in that the material cooler (40) has a fifth cooling zone (45), wherein the fifth cooling zone (45) is adjacent to the fourth cooling zone (44), wherein the fifth cooling zone (45) has a second water supply (55) for water at more than 100 °C, wherein the second water supply (55) is arranged below the support surface or in the material layer arranged on the support surface for producing a water vapor barrier layer in the material layer.
6. Material cooler (40) according to claim 5, characterized in that the material cooler (40) has a seventh cooling zone (47), wherein the seventh cooling zone (47) is adjacent to the fourth cooling zone (44), wherein the seventh cooling zone (47) is designed for operation with enriched oxygen with a proportion of more than 50 vol.%, preferably more than 90 vol.%, oxygen.
7. Material cooler (40) according to claim 5, characterized in that the material cooler (40) has a sixth cooling zone (46), wherein the sixth cooling zone (46) is adjacent to the fifth cooling zone (45), wherein the sixth cooling zone (46) is designed for operation with enriched oxygen with a proportion of more than 50 vol.%, preferably more than 90 vol.%, oxygen.
8. Material cooler (40) according to one of claims 2 to 7, characterized in that the third cooling zone (43) has a gas outlet, wherein the gas outlet is connected to the carbon dioxide supply (54) and / or a calciner.
9. Material cooler (40) according to one of the preceding claims, characterized in that a first mechanical gas separation device is arranged between the first cooling zone (41) and the second cooling zone (42).
10. A method for operating a material cooler (40) according to any one of the preceding claims, wherein an application atmosphere is present on the application side and a discharge atmosphere is present on the discharge side, wherein the application atmosphere and the discharge atmosphere are separated by a water vapor barrier layer in the material to be cooled in the second cooling zone (42).
11. The method according to claim 10, characterized in that the application atmosphere has a higher oxygen content and a lower nitrogen content than the discharge atmosphere.
12. The method according to one of claims 10 to 11, characterized in that the second cooling zone (42) is non-condensing, so that the water remains as water vapor in the gas phase.