Heat exchangers and heat exchange systems

Abstract

DEPCT69 Which is equipped with a heat exchanger that can increase the installation density. The heat transfer medium in a heat exchanger is affected as the selectivity of the medium expands. Heat transfer, in relation to the arts and sciences involved, includes heat exchangers, including chambers. The first heat exchanger includes an area filled with granular heat transfer medium. The first inlet channel is configured to bring in a processed high-temperature gas into area one. The first vent is positioned vertically above the first inlet and is configured accordingly. Vent the gases from the first heat exchanger to the second heat exchanger that was placed there. The location beneath the heat exchanger is the first in the vertical direction and includes the second area that is filled. The granular heat transfer medium flows in from the heat exchanger at one inlet channel. The two chambers are configured to introduce a second gas, which is at a lower temperature than the first, into the second region / channel. A second vent is positioned vertically above the second inlet and is configured accordingly. Vent the gases from the second heat exchanger and the control components which are positioned at a specific location. The location, or rather, the area between the ends of the first region and the sides of the heat exchanger. The two ends of the second area on the sides of the heat exchanger chamber are where the first control piece is located. The gas flow rate can be controlled;

Description

Heat exchangers and heat exchange systems

[0001] The present invention relates to a heat exchanger, and more particularly to a heat exchanger for exchanging heat of a gas through a solid heat medium, and to a heat exchange system including such a heat exchanger.

[0002] In recent years, reducing carbon dioxide emissions has become an important issue in order to curb global warming, and there is a need to efficiently recover the carbon dioxide emitted in the cement manufacturing process. From this perspective, the present applicant has proposed a technology in which a calciner is placed upstream of a rotary kiln together with a preheating device in order to promote decarbonation of cement raw materials (see Patent Document 1).

[0003] Furthermore, Patent Document 2 below discloses a technology for lowering the temperature of high-temperature gas by heat exchange with a particulate heat medium.

[0004] JP 2022-96064 A JP 2003-254688 A

[0005] From the viewpoint of improving the efficiency of heat utilization, it is preferable to reuse the high-temperature exhaust gas from the calciner by heat exchange. For this reason, the present inventors have investigated the possibility of lowering the temperature of the high-temperature exhaust gas from the calciner through the heat exchanger disclosed in Patent Document 2.

[0006] However, the method of Patent Document 2 requires the use of a heat transfer medium having a specific specific gravity and particle size, which limits the selectivity of the heat transfer medium. In addition, the amount of heat transfer medium that can be used is small relative to the overall size of the heat exchanger, so there is room for further improvement in the efficiency of heat recovery.

[0007] In view of the above problems, the present invention aims to provide a heat exchanger and a heat exchange system that can increase the installation density of heat media within the heat exchanger while expanding the selection of usable heat media compared to conventional methods.

[0008] a first inlet for introducing a high-temperature first gas to be treated into the first region; a first outlet for discharging the gas in the first heat exchange chamber, the first inlet being positioned vertically above the first inlet; a second heat exchange chamber for introducing a second gas having a lower temperature than the first gas into the second region; a second outlet for discharging the gas in the second heat exchange chamber, the second inlet being positioned vertically below the first heat exchange chamber and in communication with the first heat exchange chamber, the second inlet being positioned vertically above the second inlet and discharging the gas in the second heat exchange chamber; and a regulating member for controlling the flow rate of gas, the regulating member being positioned at one or more locations between the end of the first region on the second heat exchange chamber side and the end of the second region on the first heat exchange chamber side.

[0009] The heat exchanger includes a restricting member that controls the gas flow rate within the connecting section that connects the multiple heat exchange chambers, thereby preventing backflow of low-temperature gas present in the second heat exchange chamber from the second heat exchange chamber toward the first heat exchange chamber.

[0010] Furthermore, the restricting member can prevent the heat medium filled in the first heat exchange chamber from flowing out to the second heat exchange chamber. This allows the heat medium to be densely arranged, making it possible to narrow the area (first area) for heat exchange with the high-temperature first gas. Hereinafter, for convenience, the heat medium filled in the first heat exchange chamber may be referred to as the "first heat medium."

[0011] Furthermore, according to the above configuration, by filling the region (first region) in the first heat exchange chamber with the heat medium, heat exchange with the first gas can be performed, and therefore there are no significant restrictions on the specific gravity or particle size of the material that can be used as the heat medium, as described in Patent Document 2. For this reason, the heat medium can be made of a general-purpose material, such as ceramics such as alumina or metals such as iron, and there are no restrictions on particle size as long as it is large enough to be filled.

[0012] In the heat exchanger, the high-temperature first gas flows in through the first inlet and is supplied to a region (first region) in the first heat exchange chamber filled with a granular heat medium, where it exchanges heat with the granular heat medium. The first gas is then discharged through the first outlet. The restricting member prevents the gas in the second heat exchange chamber, into which the low-temperature second gas is introduced, from flowing back into the first heat exchange chamber.

[0013] By opening the regulating member at a predetermined timing, the heat medium (first heat medium) after heat exchange in the first heat exchange chamber is guided into the second heat exchange chamber. Then, by closing the regulating member, the heat medium (hereinafter, for convenience, sometimes referred to as the "second heat medium") sent from the first heat exchange chamber remains and fills the second heat exchange chamber. A low-temperature second gas flowing in through the second inlet is supplied to the second heat exchange chamber, and heat is again exchanged between the second heat medium and the filled second heat exchange chamber. The second gas after heat exchange is discharged from the second outlet.

[0014] As a result, the heat medium filled in the first heat exchange chamber and heated by heat exchange with the high-temperature first gas is cooled by heat exchange with the low-temperature second gas in the second heat exchange chamber. Therefore, the heat medium recovered from the second heat exchange chamber can be reused by returning it to the first heat exchange chamber. Specifically, the heat exchanger may include a transport mechanism for introducing the heat medium recovered from the second heat exchange chamber into the first heat exchange chamber from above.

[0015] For example, exhaust gas from a calciner installed in a cement factory can be introduced into the first heat exchange chamber from the first inlet as the first gas, and the gas discharged from the second outlet can be used to preheat the combustion-supporting gas introduced into the calciner, thereby making it possible to effectively utilize the exhaust heat of the high-temperature exhaust gas from the calciner. In this case, for example, the exhaust gas from the calciner used as the first gas has a temperature of about 800°C to 1000°C, and the gas discharged from the second outlet has a temperature of about 400°C to 600°C.

[0016] In the above, the gas discharged from the first outlet may also be used to preheat the combustion-supporting gas. Also, a high-concentration carbon dioxide-containing gas recovered through a facility for recovering carbon dioxide contained in exhaust gas from a calciner installed in a cement factory may be introduced into the first heat exchange chamber from the first inlet as the first gas.

[0017] The regulating member preferably has an openable / closable structure. For example, it may be configured as an openable / closable partition plate, valve, rotary valve, damper, gate, feeder, pusher, or the like. Closing the regulating member can stop the flow of gas and heat medium. The regulating member may be configured so that its opening degree is adjustable by a control unit or the like. Specifically, the heat exchanger may include thermometers installed at one or more locations belonging to a group consisting of the first inlet, the first outlet, the second inlet, and the second outlet, and the opening degree of the regulating member may be adjusted based on temperature information measured by the thermometers.

[0018] The heat exchanger may include a communication section that connects the first heat exchange chamber and the second heat exchange chamber and guides the heat medium filled in the first heat exchange chamber to the second heat exchange chamber, and a first regulating member that serves as the regulating member and is positioned within the communication section downstream of the first heat exchange chamber in terms of the flow direction of the heat medium, or at the boundary between the communication section and the second heat exchange chamber.

[0019] According to the above configuration, the effect of suppressing the backflow of low-temperature gas from the second heat exchange chamber, which is in a low-temperature environment, to the first heat exchange chamber, which is in a high-temperature environment, is further enhanced.

[0020] The second discharge port may be disposed at a position vertically above the first stop member.

[0021] According to the above configuration, the low-temperature second gas introduced into the second heat exchange chamber undergoes heat exchange while moving upward within the area (second area) filled with the second heat medium, and can then be discharged from the second exhaust port located above.

[0022] The heat exchanger may include a second regulating member as the regulating member, which is arranged in the connecting portion at a position upstream of the first regulating member in the flow direction of the heat medium, or at a position at the boundary between the connecting portion and the first heat exchange chamber, and a dust removal mechanism which is arranged in the connecting portion at a position between the second regulating member and the first regulating member in the flow direction of the heat medium, and which removes dust finer than the particles of the heat medium.

[0023] By providing the second stop member, the heat medium (first heat medium) is retained in the first heat exchange chamber, and by opening the second stop member, the first heat medium can flow into the connecting portion from the first heat exchange chamber. As described above, the heat medium is filled in a predetermined region (first region) in the first heat exchange chamber, and the heat medium particles are in close contact with each other. Therefore, as the heat medium particles move, contact with other heat medium particles can generate dust, which can adhere to the surfaces of the heat medium particles. According to the above configuration, a dust removal mechanism is provided in the connecting portion, so dust adhering to the heat medium while it is moving within the connecting portion can be removed. This maintains the quality of the heat medium recovered through the second heat exchange chamber, and reduces a decrease in heat exchange efficiency even when it is reused.

[0024] Such a dust removal mechanism can be configured, for example, by a sieve member having an opening smaller than the particle size of the heat medium particles. The dust removal mechanism may be disposed vertically below the second stop member. In this way, when the second stop member is opened, the first heat medium filled in the first heat exchange chamber falls due to gravity or flows along the inner wall of the connecting portion, so that the first heat medium passes over the sieve member while maintaining momentum, thereby efficiently removing dust.

[0025] From a similar viewpoint, the communication section may have a stirring member that stirs the granular heat medium flowing therethrough. With this configuration, the first heat medium moves within the communication section while being given momentum by an external force from the stirring member, and therefore the first heat medium passes over the sieve member while maintaining momentum, thereby enabling efficient removal of dust.

[0026] A dust removal mechanism for removing dust from the particles of the heat medium recovered from the second heat exchange chamber may be further provided at a position downstream of the second heat exchange chamber.

[0027] According to the heat exchanger of the present invention, the selection of heat transfer media that can be used can be broadened compared to conventional heat exchangers, and the installation density of heat transfer media can be increased.

[0028] Fig. 1 is a conceptual diagram schematically showing the configuration of an embodiment of a heat exchanger. Fig. 2 is a diagram extracting the vicinity of the first heat exchange chamber 10 from Fig. 1. Fig. 3 is a diagram extracting the vicinity of the second heat exchange chamber 20 from Fig. 1. Fig. 4 is a diagram extracting the vicinity of the second heat exchange chamber 20 from Fig. 1. Fig. 5 is a diagram extracting the vicinity of the second heat exchange chamber 20 from Fig. 1. Fig. 6 is a diagram schematically showing the configuration of a heat exchange system including cement plant equipment. Fig. 7 is a conceptual diagram schematically showing the configuration of another embodiment of a heat exchanger.

[0029] Hereinafter, embodiments of a heat exchanger and a heat exchange system according to the present invention will be described with reference to the accompanying drawings. Note that the drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily correspond to the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily correspond to the actual dimensional ratios.

[0030] In the following drawings, the flow of gas is schematically shown by a two-dot chain line, and the flow of solid (heat medium 3 described later) is schematically shown by a one-dot chain line.

[0031] Fig. 1 is a conceptual diagram showing the configuration of an embodiment of a heat exchanger. Figs. 2 to 5 are each an extracted portion of Fig. 1. The following description will be given with reference to Figs. 1 to 5 as appropriate.

[0032] 1 includes a first heat exchange chamber 10, a second heat exchange chamber 20 installed vertically below the first heat exchange chamber 10, and a communication section 30 connecting the first heat exchange chamber 10 and the second heat exchange chamber 20. In each figure, the +Z direction corresponds to the vertically upward direction.

[0033] The first heat exchange chamber 10 is filled with a granular heat medium 3 in at least a portion thereof. In FIG. 2, the region filled with the heat medium 3 is designated by the symbol "first region 15." FIG. 2 is a diagram illustrating the vicinity of the first heat exchange chamber 10 extracted from the heat exchanger 1 in FIG. 1. The heat medium 3 may be made of a general-purpose material, such as ceramics typified by alumina or metals typified by iron. The particle size of the heat medium 3 is arbitrary as long as it is large enough to fill the first region 15. As an example, taking dust clogging into consideration, the particle size of the heat medium 3 is 2 to 30 mm, preferably 5 to 20 mm.

[0034] The first heat exchange chamber 10 includes a first inlet 11 through which a high-temperature first gas G1 is introduced, and a first outlet 13 through which a gas G1a is discharged after the first gas G1 has traveled through the heat medium 3 and exchanged heat. The first gas G1 introduced from the first inlet 11 is blown into the first region 15 filled with the heat medium 3. Because the first gas G1 introduced from the first inlet 11 tends to flow vertically upward within the first heat exchange chamber 10, the first outlet 13 is preferably located vertically above the first inlet 11.

[0035] The first gas G1 is a high-temperature gas to be subjected to heat exchange. As will be described later, the first gas G1 may be exhaust gas from a calciner installed in a cement factory, and in this case, the temperature of the first gas G1 is about 800°C to 1000°C. The first gas G1 may also be exhaust gas from a location other than a cement factory (for example, a steel mill, an incinerator, a power plant, etc.).

[0036] There may be a high possibility of clogging due to reasons such as an extremely high dust content in the first gas G1. As a measure to suppress clogging, a classification device such as a cyclone may be installed upstream of the first inlet 11 for the first gas G1. In other words, the first gas G1 from which dust has been removed by the classification device may be introduced into the first inlet 11.

[0037] In addition, clogging is also likely to occur when the first gas G1 contains chlorine or the like. In such a case, control may be performed to lower the temperature of the first gas G1. To cool the first gas G1, a branch duct may be provided before the first inlet 11, and a low-temperature gas such as carbon dioxide, oxygen, air, or water vapor may be introduced depending on the first gas G1, or the first gas G1 may be cooled by spraying water.

[0038] The temperature and flow rate of the first gas G1 may be controlled based on a signal from a control unit (not shown). The signal from the control unit may correspond to the temperature of the heat medium 3, the first gas G1, the gas G1a introduced to the first outlet 13, etc. In this case, a thermometer for measuring the temperature of the heat medium 3 may be installed in the first heat exchange chamber 10, a thermometer for measuring the temperature of the first gas G1 may be installed in the first inlet 11, and a thermometer for measuring the temperature of the gas G1a may be installed in the first outlet 13.

[0039] The high-temperature first gas G1 introduced through the first inlet 11 passes through a first region 15 filled with the heat medium 3, whereby heat is exchanged between the first gas G1 and the heat medium 3, and then the gas G1a having a lower temperature than the first gas G1 is discharged through a first outlet 13. In Fig. 2, part of the heat medium 3 is not shown in order to clearly show in the drawing that the gas flows through the region filled with the heat medium 3. A similar illustration method may be adopted in Fig. 3 and subsequent figures.

[0040] At least a portion of the second heat exchange chamber 20 is filled with the granular heat medium 3. In Figures 3 and 4, the region filled with the heat medium 3 is designated by the symbol "second region 25." Figures 3 and 4 are drawings illustrating the vicinity of the second heat exchange chamber 20 extracted from the heat exchanger 1 in Figure 1. As will be described later, the heat medium 3 present in the second heat exchange chamber 20 is introduced from the first heat exchange chamber 10 side, filling the second region 25.

[0041] The second heat exchange chamber 20 includes a second inlet 21 through which a second gas G2 having a lower temperature than the first gas G1 is introduced, and a second outlet 23 through which a gas G2a is discharged after the second gas G2 has traveled through the heat medium 3 and been heat exchanged. The second gas G2 introduced from the second inlet 21 is blown into the second region 25 filled with the heat medium 3. The second gas G2 introduced from the second inlet 21 tends to flow vertically upward within the second heat exchange chamber 20, and therefore the second outlet 23 is disposed at a position vertically above the second inlet 21.

[0042] As will be described later, the second heat exchange chamber 20 is filled with the heat medium 3 that has been heated to a high temperature through heat exchange in the first heat exchange chamber 10. The low-temperature second gas G2 introduced through the second inlet 21 passes through the second region 25 filled with the high-temperature heat medium 3, whereby heat exchange occurs between the low-temperature second gas G2 and the heat medium 3, and then the low-temperature second gas G2 is discharged through the second outlet 23 as gas G2a having a higher temperature than the second gas G2.

[0043] The second gas G2 is a gas introduced for the purpose of cooling the heat medium 3 whose temperature has risen due to heat exchange within the first heat exchange chamber 10, and can be, for example, air, carbon dioxide gas, oxygen gas, other flammable gases, etc.

[0044] The temperature and flow rate of the second gas G2 may be controlled based on a signal from a control unit (not shown). The signal from the control unit may correspond to the temperature of the heat medium 3, the second gas G2, the gas G2a introduced to the second outlet 23, etc. In this case, a thermometer for measuring the temperature of the heat medium 3 may be installed in the connecting unit 30 and the second heat exchange chamber 20, a thermometer for measuring the temperature of the first gas G2 may be installed in the second inlet 21, and a thermometer for measuring the temperature of the gas G2a may be installed in the second outlet 23.

[0045] As described above, the communication section 30 communicates the first heat exchange chamber 10 and the second heat exchange chamber 20. The heat medium 3 filled in the first heat exchange chamber 10 can be sent to the second heat exchange chamber 20 through the communication section 30.

[0046] A detailed description will be given of the structure of the communication section 30. Figures 3 to 5 are drawings illustrating the vicinity of the communication section 30 extracted from the heat exchanger 1 of Figure 1.

[0047] As shown in FIG. 3 , the communication section 30 of the heat exchanger 1 of this embodiment is provided with regulating members (51, 52, 53). These regulating members (51, 52, 53) have the function of controlling the flow of the heat transfer medium 3. More specifically, the regulating members (51, 52, 53) are composed of partition plates, valves, rotary valves, dampers, gates, feeders, pushers, etc., and have the function of blocking the flow of the heat transfer medium 3 and, conversely, canceling the blocked state. The opening degree of the regulating members (51, 52, 53) may be controlled based on a signal from a control unit (not shown). At least one of the regulating members (51, 52, 53) is structured to block not only the flow of the heat transfer medium 3 but also the flow of gas.

[0048] 1 illustrates a situation in which the restricting member 51 is closed, thereby confining the heat medium 3 in the first heat exchange chamber 10 within the first heat exchange chamber 10. Also, in the situation illustrated in FIG. 1, the restricting member 53 is also closed. Therefore, the gas G2a obtained after heat exchange between the low-temperature second gas G2 and the heat medium 3 in the second heat exchange chamber 20 is not guided into the communication portion 30, but is instead discharged from the second discharge port 23, as described above. As illustrated in FIGS. 1 and 3, the second discharge port 23 is preferably disposed vertically above the restricting member 53.

[0049] In this embodiment, the restricting member 53 corresponds to the "first restricting member," and the restricting member 51 corresponds to the "second restricting member."

[0050] When heat exchange between the first gas G1 and the heat medium 3 is carried out in the first heat exchange chamber 10 for a certain period of time or more, the temperature of the heat medium 3 increases. When the temperature of the heat medium 3 filled in the first heat exchange chamber 10 increases, the efficiency of heat exchange in the first heat exchange chamber 10 decreases, so it is necessary to replace this heat medium 3 with a low-temperature heat medium 3. This method will be described below.

[0051] First, as shown in FIG. 3 , the restricting member 51 is opened. As a result, the heat medium 3 that had been retained in the first heat exchange chamber 10 is introduced into the communication part 30. The opening degree of the restricting member 51 may be controlled by a control part (not shown) based on a signal from the control part, depending on, for example, the temperature of the first gas G1, the temperature of the heat medium 3 in the first heat exchange chamber 10, the temperature of the gas G1a introduced to the first outlet 13, or the elapsed time since the restricting member 51 was last closed. In this case, a thermometer that measures the temperature of the heat medium 3 may be installed in the first heat exchange chamber 10, a thermometer that measures the temperature of the first gas G1 may be installed in the first inlet 11, or a thermometer that measures the temperature of the gas G1a introduced to the first outlet 13 may be installed in the first outlet 13.

[0052] In the example shown in FIG. 3 , a sieve member 61 is installed on a portion of the wall surface of the communication section 30. This sieve member 61 has an opening smaller than the particle size of the heat transfer medium 3. As the heat transfer medium 3 passes over the upper surface of the sieve member 61, fine dust 7 adhering to the surface of the heat transfer medium 3 falls below the sieve member 61 and accumulates in the dust collection section 63. In this embodiment, the sieve member 61 corresponds to a "dust removal mechanism." By passing the heat transfer medium 3 over the upper surface of the sieve member 61, a decrease in heat exchange efficiency caused by the dust 7 can be suppressed when the heat transfer medium 3 is reused in the first heat exchange chamber 10, as described below. However, whether or not the heat exchanger 1 includes a dust removal mechanism is optional.

[0053] When the heat medium 3 filled in the first heat exchange chamber 10 is guided to the second heat exchange chamber 20, the regulating member 53 is closed even when the aperture of the regulating member 51 is opened, so that the relatively low-temperature gas G2a present in the second heat exchange chamber 20 is prevented from flowing back to the first heat exchange chamber 10 through the connecting portion 30.

[0054] 1 and 4 , the heat exchanger 1 includes a delivery mechanism 42. When the delivery mechanism 42 is opened, the heat medium 3 filled in the second heat exchange chamber 20, more specifically, the heat medium 3 cooled by heat exchange with the low-temperature second gas G2, is delivered to the transport mechanism 41. The delivery mechanism 42 is configured with, for example, a partition plate, a valve, a rotary valve, a damper, a gate, a feeder, a pusher, etc.

[0055] The cooled heat transfer medium 3 sent out through the delivery mechanism 42 is raised through the transport mechanism 41 and delivered to the heat transfer medium introduction mechanism 45 installed above the first heat exchange chamber 10. When the heat transfer medium introduction mechanism 45 is opened to a predetermined opening, the cooled heat transfer medium 3 is newly sent into the first heat exchange chamber 10. As shown in FIG. 1 , a heat transfer medium storage mechanism 43 may be installed to send additional heat transfer medium 3 to the transport mechanism 41. In this case, as with the delivery mechanism 42, new heat transfer medium 3 may be sent to the transport mechanism 41 by adjusting the opening of a partition plate, valve, rotary valve, damper, gate, feeder, pusher, etc. As the transport mechanism 41, a conveyor, a pneumatic transport device, a feeder, a batch-type lifting device, etc. may be used.

[0056] The flow rate of the heat medium 3 in the heat medium introduction mechanism 45 and the discharge mechanism 42 may be controlled based on a signal from a control unit (not shown). The signal from the control unit may correspond to the temperature of the heat medium 3, the temperatures of the first gas G1, the gas G1a introduced to the first discharge port 13, the second gas G2, and the gas G2a introduced to the second discharge port 23, etc. In this case, a thermometer for measuring the temperature of the heat medium 3 may be installed in each of the heat medium introduction mechanism 45, the first heat exchange chamber 10, the second heat exchange chamber 20, and the discharge mechanism 42, and a thermometer for measuring the temperature of the first gas G1 may be installed in the first inlet 11, the temperature of the gas G1a may be installed in the first discharge port 13, the temperature of the second gas G2 may be installed in the second inlet 21, and the temperature of the gas G2a may be installed in the second discharge port 23.

[0057] Next, as shown in Fig. 5, the restricting member 51 is closed, and then the restricting members 52 and 53 are opened. As a result, the heat medium 3 that was retained in the communication section 30, as described above with reference to Fig. 4, is introduced into the second heat exchange chamber 20. At this time, it is expected that a portion of the relatively low-temperature gas G2a present in the second heat exchange chamber 20 will flow back into the communication section 30. However, because the restricting member 51 is closed, the communication section 30 and the first heat exchange chamber 10 are separated. In other words, the restricting member 51 controls the flow rate of the gas. As a result, the relatively low-temperature gas G2a that has flowed back into the communication section 30 is prevented from flowing back into the first heat exchange chamber 10.

[0058] Thereafter, the restricting members (52, 53) are closed, and the state returns to the state shown in Fig. 1. That is, according to the heat exchanger 1 described above, the heat medium 3, whose temperature has increased due to heat exchange with the high-temperature first gas G1 in the first heat exchange chamber 10, is sent into the second heat exchange chamber 20, where it is cooled by heat exchange with the low-temperature second gas G2, and then returned to the first heat exchange chamber 10 again via the transport mechanism 41.

[0059] 6 is a diagram showing an example of a case where the heat exchanger 1 is used for heat exchange of exhaust gas from a cement factory 2. The cement factory 2 includes a preheater 71 for preheating cement clinker raw materials, a rotary kiln 75 for burning the cement clinker raw materials preheated in the preheater 71 using a burner 76, a calciner 72 for promoting decarbonation of the cement clinker raw materials, and a clinker cooler 77 for cooling the burned cement clinker.

[0060] The calciner 72 is located upstream of the rotary kiln 75 together with the preheater 71 for the purpose of promoting decarbonation of the cement clinker raw materials. A combustion-supporting gas having a higher oxygen concentration than air is introduced into the calciner 72 from a combustion-supporting gas supply device 74 via a flow path 79 to heat and decarbonate the cement clinker raw materials. The decarbonated cement clinker raw materials are sent to the rotary kiln. Examples of the combustion-supporting gas supply device 74 include an oxygen tank, an air separation device that separates oxygen from air, and a water electrolysis device that generates oxygen by electrolysis of water. Specifically, the calciner 72 heats and decomposes calcium carbonate (CaCO3), the main component of limestone contained in the cement clinker raw materials, into quicklime (CaO) and carbon dioxide (CO2).

[0061] When the cement clinker raw material is heated using a combustion-supporting gas in the calciner 72, the partial pressure of carbon dioxide increases. Therefore, a higher temperature is required to promote decarbonation, and therefore the temperature must be higher than when air is used as the combustion-supporting gas.

[0062] 6, the gas discharged from the second outlet 23 provided in the second heat exchange chamber 20 of the heat exchanger 1 shown in FIG. 1, i.e., the gas G2a whose temperature has increased due to heat exchange with the low-temperature second gas G2 in the second heat exchange chamber 20, is introduced into the combustion-supporting gas supply device 74. As a result, a high-temperature combustion-supporting gas is generated. Note that while FIG. 6 shows an example in which the gas G2a is introduced into the combustion-supporting gas supply device 74 itself, heat exchange may also be performed between the combustion-supporting gas generated in the combustion-supporting gas supply device 74 and the high-temperature gas G2a discharged from the second outlet 23.

[0063] In the example shown in FIG. 6, heat is also exchanged between the high-temperature gas discharged from the clinker cooler 77 through the exhaust gas tower 78 and the combustion-supporting gas, but this configuration is merely one example.

[0064] The exhaust gas discharged from the calciner 72 through the calciner exhaust gas discharge path 73 has a high temperature of approximately 800°C to 1000°C. Therefore, in the example shown in FIG. 6 , the exhaust gas from the calciner 72 is introduced into the first heat exchange chamber 10 as the high-temperature first gas G1 through the first inlet 11 of the heat exchanger 1 shown in FIG. 1 , and heat exchange occurs between the first gas G1 and the heat medium 3, as described above. If the exhaust gas from the calciner 72 contains a high dust content, a classification device such as a cyclone may be installed upstream of the first inlet 11 for the first gas G1 to prevent clogging, as described above. Clogging is also likely to occur when the exhaust gas from the calciner 72 contains a large amount of chlorine or the like. In this case, the temperature of the first gas G1 may be controlled to be lowered. To cool the first gas G1, a branch duct may be installed upstream of the first inlet 11, and low-temperature carbon dioxide gas, oxygen gas, or water vapor may be introduced depending on the first gas G1. Alternatively, water may be sprayed onto the first gas G1.

[0065] Here, the carbon dioxide gas may be a high-concentration carbon dioxide-containing gas recovered from the exhaust gas from the calciner 72 using a device that recovers carbon dioxide contained in the exhaust gas from the calciner 72.

[0066] Another embodiment will now be described.

[0067] <1> Fig. 7 is a diagram schematically illustrating the configuration of another embodiment of the heat exchanger 1, following Fig. 1. The heat exchanger 1 shown in Fig. 7 has different structures of the regulating members 51 and 53.

[0068] As shown in Figure 7, the regulating members 51 and 53 may be equipped with shielding blade members, and may be configured to switch between a state in which the flow path is secured and a state in which the flow path is regulated by the blade members by rotating.

[0069] 7 includes an agitator 67 in the communication section 30. The agitator 67 agitates the heat transfer medium 3 sent from the first heat exchange chamber 10 into the communication section 30, thereby allowing dust 7 adhering to the surface of the heat transfer medium 3 to be collected through a sieve member 61 serving as a dust removal mechanism. The agitator 67 may be included in the heat exchanger 1 shown in FIG. 1.

[0070] <2> The heat exchanger 1 shown in Fig. 1 includes a plurality of regulating members (51, 52, 53). The heat exchanger 1 shown in Fig. 7 includes a plurality of regulating members (51, 53). However, the heat exchanger 1 only needs to be able to prevent the relatively low-temperature gas G2a present in the second heat exchange chamber 20 from flowing back into the first heat exchange chamber 10. Therefore, the heat exchanger 1 only needs to be configured to include a regulating member in at least one location.

[0071] More specifically, it is sufficient that a regulating member is arranged at one or more locations between the end of the first region 15 in the first heat exchange chamber 10 on the second heat exchange chamber 20 side, in which the heat medium 3 is filled, and the end of the second region 25 in the second heat exchange chamber 20 on the first heat exchange chamber 10 side, in which the heat medium 3 is filled.

[0072] However, if the restricting member is provided in only one location, when the heat medium 3 flows from the first heat exchange chamber 10 to the second heat exchange chamber 20, the relatively low-temperature gas in the second heat exchange chamber 20 may flow back into the first heat exchange chamber 10. For this reason, it is preferable to provide restricting members in two or more locations.

[0073] <3> The heat exchanger 1 of the above embodiment is provided with the communication section 30 that communicates the first heat exchange chamber 10 and the second heat exchange chamber 20. However, the first heat exchange chamber 10 and the second heat exchange chamber 20 may be directly connected to each other. In this case, a restricting member may be disposed near the boundary between the first heat exchange chamber 10 and the second heat exchange chamber 20.

[0074] <4> The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to provide a better understanding of the present invention, and the present invention is not necessarily limited to those having all of the configurations described. The scope of the present invention is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0075] REFERENCE SIGNS LIST 1: Heat exchanger 2: Cement plant 3: Heat transfer medium 7: Dust 10: First heat exchange chamber 11: First inlet 13: First outlet 15: First area 20: Second heat exchange chamber 21: Second inlet 23: Second outlet 25: Second area 30: Communication section 41: Conveying mechanism 42: Delivery mechanism 43: Heat transfer medium storage mechanism 45: Heat transfer medium introduction mechanism 51, 52, 53: Restricting member 61: Sieve member 63: Dust recovery section 67: Stirring member 71: Preheater 72: Calciner 73: Calciner exhaust gas discharge path 74: Combustion-supporting gas supply device 75: Rotary kiln 76: Burner 77: Clinker cooler 78: Exhaust gas tower 79 : Flow path G1: First gas G2: Second gas

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