Method for producing cement with sluice devices, filter system and cement production system
Patent Information
- Application Number
- EP2023754109
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-03
- Filing Date
- 2023-08-03
- Publication Date
- 2025-06-11
Smart Images
Figure 1.1
Abstract
Description
[0001] Cement production process with lock devices, filter system and cement production plant
[0002] The invention relates to a method for removing dust from a filter system in a cement production plant, in which raw materials for producing cement are burned in a kiln system, the resulting flue gas is dedusted in the filter system using a filter device and the resulting dust is removed via a discharge opening of the filter device.
[0003] Furthermore, the invention relates to a filter system for dedusting flue gas from a cement production plant.
[0004] Furthermore, the invention relates to a cement production plant with a kiln plant, in particular a rotary kiln, a filter plant for dedusting flue gases and preferably a preheating tower.
[0005] During cement production, the resulting flue gases are filtered and thus dedusted using filter systems. Filter systems can be installed at various locations in cement production plants, for example, upstream of a catalyst or in a bypass. The dust generated during filtering typically exits through a discharge opening in the filter device and is then transported to a collection point, usually by a screw conveyor or other conveying device.
[0006] In state-of-the-art filter systems, ambient air can enter the cement production plant through the discharge opening, which can negatively impact the cement production process. This is particularly the case if there is a negative pressure in the filter system. In new types of cement production processes, in which combustion is carried out with oxygen-enriched air or pure oxygen instead of normal ambient air in order to obtain the purest possible CO2 as exhaust gas, which can be reused in other processes, the ingress of ambient air can be disadvantageous because it reduces the proportion of CO2 produced during combustion. It would therefore be desirable to keep the ingress of ambient air - the so-called false air ingress - as low as possible in such processes. In state-of-the-art technology, attempts are therefore made to make all plant components as airtight as possible.However, necessary system openings, such as the discharge openings of the filter devices, continue to pose a problem because they still allow ambient air to enter the system.
[0007] EP 1 344 732 A1 discloses a rotary valve in which a sealing gas opening is arranged in the region of the housing around the rotary valve, in particular on the casing wall of the housing, in order to minimize the (process) gas flow through the rotary valve. A disadvantage of the rotary valve of EP 1 344 732 A1 is that a large amount of sealing gas and large gap widths between the rotary valve and the housing are required in order to keep the (process) gas flow through the rotary valve low.
[0008] GB 2 271 114 A discloses a process for expelling unpolymerized monomers from polymer compounds in a foreign field. In this process, polymerized resin is conveyed via rotary valves alternately into vacuumed and pressurized areas. The vacuum poses the risk of ambient air being drawn in through the system openings.
[0009] CN 103625929 B discloses an arrangement of rotary valves, between which ambient air is introduced in order to avoid negative pressure in a subsequent part of the plant, a material storage tank.
[0010] In light of these statements, it is an object of the present invention to eliminate or at least mitigate the disadvantages of the prior art. Preferably, the object of the present invention is to reduce or even completely prevent the ingress of false air via a discharge opening of a filter system in a cement production plant. This object is achieved by a method according to claim 1, by a filter system according to claim 10, and by a cement production plant according to claim 14. Preferred embodiments are specified in the dependent claims.
[0011] According to the invention, in a method of the type mentioned at the outset, two lock devices, in particular rotary valves, which are connected in series to the discharge opening and are interconnected via a connecting element, in particular a connecting pipe, are provided, and which transport the accumulating dust from the discharge opening to the outside. A sealing gas inlet opens into the connecting element between the lock devices and a sealing gas is introduced into the connecting element in order to block the penetration of ambient air into the filter device. "Connected in series" means that accumulating dust passes from one lock device to the other. Advantageously, the introduction of the sealing gas into the connecting element which connects the lock devices to one another can greatly reduce or even eliminate the undesired entry of ambient air.can be prevented because the sealing gas penetrates to the outside through any leaks and in this way displaces the ambient air. If there is a negative pressure in the filter device, only the sealing gas is sucked in and not the ambient air. A filter system comprises at least one filter device, two airlock devices connected to it, the connecting element and the sealing gas inlet. The connecting element, which is preferably designed as a connecting pipe, connects the housings of the two airlock devices to one another, preferably in a gas-tight manner. For this purpose, two opposite ends of the connecting element are each connected to the airlock devices. Any dust that has been filtered out of the flue gas by the filter device can pass through the connecting element from one airlock device to the other and from there to the outside.One of the lock devices - referred to below as the first lock device - is connected at its inlet side via a connecting part, preferably in a gas-tight manner, to the discharge opening of the filter device, and at its outlet side, preferably in a gas-tight manner, to the connecting element. The other lock device at the other end of the connecting element - referred to below as the second lock device - is connected at its inlet side, preferably in a gas-tight manner, to the connecting element and conveys the dust through its outlet side to the outside, i.e. to a location outside the filter system, where the dust can be collected, transported away, and / or further processed.The outlet side of the first lock device is therefore connected via the connecting element to the inlet side of the second lock device, so that dust can be carried out of the filter device via the first lock device, the connecting element and then via the second lock device. The first lock device represents the process-side lock device, while the second lock device represents the atmosphere-side lock device. The lock devices can in particular be designed as rotary valves. Rotary valves have a stationary housing (stator) and a rotatable rotary valve (rotor), which is preferably driven by an electric motor. Rotary valves take in material at an inlet side and release it in metered form at the outlet side.Only a small gap of preferably less than 1 mm is provided between the walls of the cell wheel and the housing in order to ensure tightness between the inlet and outlet sides. However, cell wheel locks cannot be completely tight due to the gap and ambient air is also conveyed into the cement production plant through the cells rotated from the outlet side to the inlet side. According to the invention, the sealing gas is therefore introduced into the connecting element between the cell wheel locks and displaces the ambient air or blocks the penetration and spread of the ambient air. In particular, ambient air which penetrates via the second, atmosphere-side lock device is displaced or blocked in this way. The sealing gas inlet can have a valve. The valve can also be arranged in a line for the sealing gas. In this way, the sealing gas can be regulated.The sealing gas inlet preferably opens into an inner wall of the connecting element. It is also possible to provide a plurality of sealing gas inlets which open into the connecting element. The filter system can have a plurality of filter devices connected in parallel or in series. Each filter device can also have a plurality of discharge openings, to each of which lock devices which are connected via a connecting element are connected in accordance with the type described. The filter device can in turn have one or more filters within a housing, which can be, for example, candle filters or bag filters. The cement production plant has at least one kiln plant and a filter plant according to the invention for filtering flue gases. In addition, the cement production plant can also have plant components such as a preheating stage, in particular a preheating tower, a catalyst and one or more bypasses.The filter system with the filter device, the two connected lock devices and the connecting element can be provided at several points in the cement production plant. For example, the filter system can be arranged after the kiln system or after a preheating stage upstream of the kiln, viewed in the direction of flow of the flue gases, in order to filter flue gases from the kiln system or the preheating stage. Additionally or alternatively, the filter system can also be used to dedust a bypass in the cement production plant. The kiln system in the cement production plant is preferably a rotary kiln. The raw materials for producing the cement clinker are fired or sintered in the kiln system.In a particularly preferred cement production process, oxygen-enriched air or essentially pure oxygen is used for combustion in the kiln in order to obtain the purest CO2 possible. As already mentioned, a preheating stage can also be provided which preheats the raw materials before they enter the rotary kiln. The preheating stage can, for example, be a preheating tower which can consist of several cyclones arranged one above the other. The raw materials enter the kiln according to the countercurrent principle. The flue gases flow against the flow of the raw materials through the preheating stage. It is preferred if CO2 or a process gas with a volume fraction of CO2 of at least 15%, preferably of at least 70%, is used as the barrier gas.As mentioned above, oxygen-enriched air or even pure oxygen can be burned instead of ordinary ambient air during cement production to produce the purest possible CO2 as the exhaust gas. In such a cement production process, CO2 as a barrier gas therefore does not represent an extraneous gas, so that there is no negative impact from the use of CO2 as a barrier gas. The preferred process gas for providing the barrier gas is kiln exhaust gas, which is preferably cleaned and / or treated before use as a barrier gas.
[0012] In one embodiment, the seal gas can be fed into the connecting element from the furnace system and / or from a seal gas supply, in particular from at least one gas tank. If oxygen-enriched air or essentially pure oxygen is used for combustion in the furnace system, essentially pure CO2 is produced, which can be used as a seal gas. In any case, it is not an external gas. For this purpose, a connecting line from the furnace system to the filter system can be used. Additionally or alternatively, the seal gas can also originate from a separate seal gas supply, for example a gas tank or pressure cylinders.
[0013] To prevent ambient air from entering the filter system, it is preferable to introduce the sealing gas at a pressure of 1 mbar to 200 mbar, preferably 10 mbar to 100 mbar, in particular 30 mbar to 50 mbar, above the static ambient pressure outside the connecting element. The pressure should not be too high to avoid damage to the pipe and lock components due to excess pressure and to keep the consumption of sealing gas as low as possible.
[0014] To facilitate dust discharge, the connecting element between the lock devices can be arranged at an angle to the horizontal, preferably substantially perpendicular, and one of the lock devices can be arranged above the other. This causes the dust to be carried downwards by gravity.
[0015] Unless otherwise stated, directions in this disclosure refer to the inertial frame and the operating state of the filter system. Essentially perpendicular means essentially parallel to the acceleration due to gravity. A horizontal direction is essentially perpendicular to the acceleration due to gravity.
[0016] Ambient air can mainly penetrate via the second, lower lock device. It is therefore advantageous if the inlet side of the second, lower lock device is constantly covered with dust because the dust has a sealing effect. In one embodiment, it can therefore be provided that a fill level measuring device measures the fill level of the accumulating dust in the connecting element. In this way, the tightness can be additionally supported. In one embodiment, a measuring sensor can monitor a lower or minimum fill level. A signal can be output when the lower or minimum fill level is exceeded or not reached. A further measuring sensor can also be provided which measures an upper or maximum fill level. A signal can be output when the upper fill level is reached.
[0017] In order to ensure tightness and prevent the penetration of ambient air, it can be provided that a control device controls the lock device, which is arranged at an end of the connecting element facing away from the filter device, in particular its speed, in such a way that a minimum fill level of the accumulating dust is maintained in the connecting element. The lock device, which is arranged at an end of the connecting element facing away from the filter device, is, as already mentioned above, also referred to as a second lock device. In one embodiment, the speed of the second lock device can be reduced or the second lock device can be brought to a standstill if the fill level falls below the minimum. If the minimum fill level is reached or exceeded, the speed of the second lock device can be increased again.The minimum fill level can, for example, correspond to a lower section of the connecting element. For example, the minimum fill level can correspond to a quarter of the length of the connecting element. If, as described above, an upper or maximum fill level is also measured, the speed of the lock device can be increased to reduce the fill level.
[0018] In order to further improve the tightness, at least one shaft seal of at least one lock device can be pressurised with barrier gas. In a preferred embodiment of the lock device as a rotary valve, shaft seals can be provided on both sides of a shaft passage through a housing of the rotary valve. Preferably, a space between the two shaft seals is pressurised with the barrier gas, in particular a compressed gas. This can prevent ambient air from entering the system because the space is pressurised to a higher pressure than the process or atmosphere side pressure. Thus, only (harmless) barrier gas can penetrate into the process or escape to the outside.
[0019] The object is also achieved by a filter system according to claim 10. The features and advantages described above in connection with the cement production process are also applicable to the filter system.
[0020] The filter system according to the invention for dedusting flue gas from a cement production plant comprises:
[0021] - a filter device with a discharge opening for any dust generated;
[0022] - two lock devices connected in series to the discharge opening, in particular rotary valves, which are connected to each other via a connecting element and are designed to convey any dust that arises; and
[0023] - a sealing gas inlet which opens into the connecting element.
[0024] The filter device has a housing that forms the discharge opening and within which one or more filters, in particular bag filters or candle filters, are arranged. The filter device can also have a plurality of discharge openings in the housing, to each of which lock devices are connected as described. The filter system can also comprise a plurality of filter devices. The connecting element is preferably designed as a connecting pipe. "Connected in series" means that accumulating dust passes from one lock device to the other.
[0025] Preferably, a fill level measuring device is provided which is designed to measure a fill level of the accumulating dust in the connecting element. As already described above, this is advantageous because the dust, particularly when it rests against the second lock device, has a sealing effect. The fill level measuring device can therefore assist the tightness. The fill level measuring device can have one or more measuring sensors. A lower measuring sensor can measure a lower or minimum fill level. An upper measuring sensor can measure an upper or maximum fill level.
[0026] Additionally, a control device can be provided and configured to control a lock device arranged at an end of the connecting element facing away from the filter device, in particular its rotational speed, such that a minimum fill level of the accumulating dust is maintained in the connecting element. This can ensure improved tightness.
[0027] It is advantageous if the filter device is designed to be essentially gas-tight, with the exception of an inlet for the flue gas, an outlet for the flue gas, and the discharge opening for any dust generated, and if one of the lock devices is connected to the discharge opening in an essentially gas-tight manner via a connecting part. Gas-tightness can be achieved, for example, by the use of seals.
[0028] This object is also achieved by a cement production plant according to claim 14. The cement production plant comprises at least one kiln, in particular a rotary kiln, a filter system for removing dust from flue gases, and preferably a preheating tower. According to the invention, the filter system is designed according to the above embodiments.
[0029] In order to introduce the sealing gas into the connecting element, the sealing gas inlet can be connected to the furnace system, depending on the design, directly or via a gas conditioning and / or gas cleaning system, and / or a sealing gas supply, in particular a gas tank.
[0030] The invention is described in more detail below with reference to figures, to which it is not intended to be limited. They show:
[0031] Fig. 1 schematically shows a cement production plant; and
[0032] Fig. 2 shows schematically a filter system with two lock devices which are connected to each other via a connecting element.
[0033] Fig. 1 shows a cement production plant 1 with a kiln system 3 designed as a rotary kiln 2, to which a clinker cooler 4 is connected. In the rotary kiln 2, raw materials (not shown) are burned to form cement clinker (not shown) and then cooled in the clinker cooler 4. Preferably, oxygen-enriched air or essentially pure oxygen is used in the combustion process, so that the combustion produces essentially pure CO2, which can be further processed or used for other processes. The raw materials are preheated in a preheating tower 5 before they are fed to the rotary kiln 2. The rotary kiln 2 is arranged between the clinker cooler 4 and the preheating tower 5. The preheating tower 5 consists of a plurality of interconnected cyclones 6.According to the countercurrent principle, the raw materials pass from a material feed 50 through the preheating tower 5 into the rotary kiln 2, whereas the kiln exhaust gases or flue gases 7 produced during combustion flow against the flow of the raw materials through the preheating tower 5. Viewed in the direction of the flue gases 7, the preheating tower 5 is therefore located after the kiln system 3. The raw materials are heated to up to 800 °C and transported in the direction of the rotary kiln 2. The flue gas 7 is simultaneously cooled from approx. 850 °C to 300 °C to 400 °C. Before the raw materials reach the rotary kiln 2, a so-called calciner (not shown) is installed in modern systems. This calciner has a separate furnace and is responsible for deacidifying the limestone by means of high temperatures and sufficient residence time.In rotary kiln 2, the raw materials are further heated and finally sintered into clinker at material temperatures of up to 1600 ° C, whereby typical clinker phases (calcium-aluminium silicates) are formed.
[0034] From the preheating tower 5, the flue gas 7 then passes via a blower 8 into a first filter system 9a (“furnace filter system”) having at least one filter device 10, with which the flue gas 7 is dedusted. The dedusted flue gas 7 then passes into a catalyst 11 for converting nitrogen oxides NO^ into harmless compounds. A reducing agent, for example a substance containing ammonia, urea and / or ammonium, is introduced via an inlet 12 before the flue gas 7 passes into the catalyst 11. The dedusted and filtered flue gas 7 then passes to the outside via a heat exchanger and a chimney (not shown).
[0035] The illustrated cement production plant 1 also has a bypass branch 14, with which a portion of the flue gas 7 from the rotary kiln 2 is not led directly into the preheating tower 5, but from a rotary kiln inlet chamber through a quench 15, a further filter system 9b ("bypass filter system") with a filter device 10 and back into the transition region between the rotary kiln 2 and the preheating tower 5. The bypass branch 14 serves to remove alkali and alkaline earth halides from the process.
[0036] For various reasons, it can be detrimental to the cement production process if ambient air is introduced into the cement production plant 1. This is particularly disadvantageous, for example, if oxygen-enriched air or pure oxygen is used during the combustion process in the rotary kiln 2 in order to obtain the most concentrated CO2 possible. The introduction of ambient air or false air can reduce the efficiency and lower the concentration of CO2, which can be detrimental to the further use of the CO2. False air can enter the cement production plant 1, for example, via discharge openings 16 of the filter systems 9a, 9b, which are provided for conveying the dust filtered out of the flue gas 7 from the filter systems 9a, 9b to a collection point 17.
[0037] In order to prevent ambient air from entering the cement production plant 1 via the discharge openings 16, the invention provides that two series-connected lock devices 18a, 18b are connected to each of the discharge openings 16 and are connected to one another via a connecting element 19. Between the lock devices 18a, 18b, a sealing gas inlet 20 opens into the connecting element 19, through which sealing gas 21 is introduced into the connecting element 19 in order to block the penetration of ambient air. The sealing gas 21 penetrates outwards via any leaks and openings (or is conveyed outwards together with the dust) and thus displaces the ambient air penetrating via leaks and mainly the lock device 18b, as will be described in more detail below. In Fig.1, two such lock devices 18a, 18b are connected to each of the discharge openings 16 of the filter system 9a and the filter system 9b, each with a sealing gas inlet 20 located therebetween. The sealing gas 21 can be provided via connecting lines from the furnace system 3 (not shown) or, as shown in Fig. 1, from gas tanks 55. A valve 56 can regulate the sealing gas 21.
[0038] Fig. 2 shows the filter system 9b in detail. The filter system 9a is larger but of identical design, except that two discharge openings 16 are provided and at each discharge opening 16 there are two lock devices 18a, 18b connected in series and connected via a connecting element 19 with a barrier gas inlet 20 in between. The filter device 10 has an inlet 51 and an outlet 52 for the flue gas 7. The filter device 10 has a housing 53 within which at least one filter 54 is arranged. In Fig. 2 it can be seen that the discharge opening 16 is arranged on an underside 22 of the housing 53 of the filter device 10, to which an inlet side 23 of the lock device 18a is connected. The lock device 18a is also referred to as the first or upper lock device 18a.The connecting element 19 is connected to an output side 24 of the first lock device 18a and connects the first lock device 18a to the input side 23 of the lock device 18b, which is also referred to as the lower or second lock device 18b. The lock devices 18a, 18b are designed as rotary valves 25. The lock devices 18a, 18b can be driven by means of electric motors 57. In the illustration shown, the connecting element 19 is a straight connecting pipe 26. Dust passes from the filter device 10 via the discharge opening 16 into the first lock device 18a, through the connecting element 19 into the second lock device 18b and from there to the collection point 17. The connecting element 19 is arranged substantially vertically so that accumulating dust is conveyed from the first lock device 18a to the second lock device 18b by gravity.The sealing gas inlet 20 opens into an inner wall of the connecting element 19. Several sealing gas inlets 20 can also be provided.
[0039] In order to reduce or prevent the ingress of ambient air, all connection points between the components of the filter system 9b are designed to be gas-tight. However, ambient air can still penetrate via the outlet side 24 of the second lock device 18b. To prevent this, the sealing gas 21 is introduced into the connecting element 19 at a pressure above the ambient pressure, for example 1.04 bar. The sealing gas 21 displaces the ingressing ambient air and pushes it (again) outwards. In the process, sealing gas also reaches the outside via the second lock device 18b. CO2 is preferably used as the sealing gas 21. The use of CO2 as the sealing gas 21 is particularly advantageous when air enriched with oxygen or essentially pure oxygen is used in the rotary kiln 2, as a result of which essentially pure CO2 is produced during the combustion process. CO2 is therefore not a foreign gas to the process.
[0040] In order to further increase the tightness, it is advantageous if there is always dust on the inlet side 23 of the second lock device 18b. For this reason, it is advantageous if the filter system 9a, 9b has a fill level measuring device 27 which measures the fill level of the accumulating dust in the connecting element 19. In the illustration shown, the fill level measuring device 27 has a lower 28a and an upper measuring sensor 28b. A minimum fill level 29 can be detected with the lower measuring sensor 28a. A maximum fill level 30 can be detected with the upper measuring sensor. When the maximum fill level 30 is reached, countermeasures can be taken. For example, there may be a defect that needs to be rectified. The speed of the second lock device 18b can also be increased in order to reduce the dust. In any case, a warning can be issued.A control device 31 can regulate the speed of the second lock device 18b, preferably with the aid of an inverter / frequency converter 32 that controls the electric motor 57, such that the minimum fill level 29 is always present in the connecting element 19. If, for example, the fill level is lower than the minimum fill level 29, the speed of the lower lock device 18b can be reduced or brought to a standstill, at least until the minimum fill level 19 is reached again.
Claims
Patent claims:
1. A method for removing dust from a filter system (9a, 9b) in a cement production plant (1), in which raw materials for producing cement are burned in a kiln system (3), the resulting flue gas (7) is dedusted in the filter system (9a, 9b) with a filter device (10) and the resulting dust is removed via a discharge opening (16) of the filter device (10), characterized in that two series-connected lock devices (18a, 18b), in particular rotary valves (25), are connected to the discharge opening (16), which are connected to one another via a connecting element (19), in particular a connecting pipe (26), and transport the resulting dust from the discharge opening (16) to the outside, wherein between the lock devices (18a, 18b) a sealing gas inlet (20) opens into the connecting element and a sealing gas (21) is introduced into the connecting element (19) is inserted,to block the ingress of ambient air into the filter device (10)., 2. Method according to claim 1, characterized in that CO2 or a process gas with a volume fraction of CO2 of at least 15%, preferably of at least 70%, is used as the sealing gas (21).
3. Method according to claim 1 or 2, characterized in that the sealing gas (21) is supplied from the furnace system (3) and / or from a sealing gas supply, in particular from at least one gas tank (55), into the connecting element (19).
4. Method according to one of claims 1 to 3, characterized in that the sealing gas (21) is introduced at a pressure of 1 mbar to 200 mbar, preferably 10 mbar to 100 mbar, in particular 30 mbar to 50 mbar, above the static ambient pressure outside the connecting element (19).
5. Method according to one of claims 1 to 4, characterized in that the connecting element (19) between the lock devices (18a, 18b) is arranged at an angle to the horizontal, preferably substantially perpendicular, and a the lock devices (18a) is arranged above the other (18b).
6. Method according to one of claims 1 to 5, characterized in that a fill level measuring device (27) measures a fill level of the accumulating dust in the connecting element (19).
7. Method according to claim 6, characterized in that a control device (31) controls the lock device (18b) which is arranged at an end of the connecting element (19) facing away from the filter device (10), in particular its speed, in such a way that a minimum fill level (29) of the accumulating dust is maintained in the connecting element (19).
8. Method according to one of claims 1 to 7, characterized in that at least one shaft seal of at least one lock device (18a, 18b) is subjected to sealing gas (21).
9. Method according to one of claims 1 to 8, characterized in that combustion air enriched with oxygen or substantially pure oxygen is used for combustion in the furnace system (3).
10. Filter system (9a, 9b) for dedusting flue gas (7) of a cement production plant (1), comprising: - at least one filter device (10) with a discharge opening (16) for accumulating dust; - two lock devices (18a, 18b) connected in series to the discharge opening, in particular rotary valves (25), which are connected to one another via a connecting element (19) and are designed to convey any dust that occurs; and - a sealing gas inlet (20) which opens into the connecting element (19).
11. Filter system according to claim 10, characterized in that a level measuring device is provided which is designed to measure a level of the accumulating dust in the to measure the connecting element.
12. Filter system (9a, 9b) according to claim 11, characterized in that a control device (31) is provided and is designed to control the lock device (18b) which is arranged at an end of the connecting element (19) facing away from the filter device (10), in particular its speed, in such a way that a minimum fill level (29) of the accumulating dust is maintained in the connecting element.
13. Filter system according to one of claims 10 to 12, characterized in that the filter device (10) is designed to be substantially gas-tight with the exception of an inlet (51) for the flue gas (7), an outlet (52) for the flue gas (7) and the discharge opening (16) for accumulating dust, and one of the lock devices (18a, 18b) is connected to the discharge opening (16) in a substantially gas-tight manner via a connecting part.
14. Cement production plant (1) with a kiln plant (3), in particular a rotary kiln (2), a filter plant (9a, 9b) for dedusting flue gases (7) and preferably a preheating tower (5), characterized in that the filter plant (9a, 9b) is designed according to one of claims 10 to 13.
15. Cement production plant (1) according to claim 14, characterized in that the sealing gas inlet (20) is connected to the kiln plant and / or a sealing gas supply, in particular a gas tank (55).