Heat exchanger for loop seal of circulating fluidized bed boiler and circulating fluidized bed boiler

Abstract

To provide a heat exchanger which is suitable for recovering heat from a flow medium in a flow layer boiler.SOLUTION: A heat exchanger (10) has: first and second heat exchanger tubes (810, 820); and first and second supply chambers (310, 320) configured to supply a flow medium to the first and second heat exchanger tubes (810, 820) respectively. The first heat exchanger tube (810) is disposed on a first side surface of a plane (P) intersecting with the first supply chamber (310), and the second heat exchanger tube (820) is disposed on a second side surface of the plane (P). The first supply chamber (310) is configured to supply the flow medium to the second supply chamber (320).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to heat exchangers. The present invention relates to particle coolers. The present invention relates to loop seal heat exchangers. The present invention relates to circulating fluidized bed boilers.

Background Art

[0002] Fluidized bed heat exchangers are known from Patent Document 1. A fluidized bed heat exchanger may be arranged connected to a steam generator in order to recover heat from the bed material of the fluidized bed. Typically, in such a heat exchanger, steam is supplied to the heat exchanger and superheated, and thus such a fluidized bed heat exchanger may be called a fluidized bed superheater. In a circulating fluidized bed boiler, a fluidized bed heat exchanger may be arranged in the loop seal. In such a case, the heat exchanger may be referred to as a loop seal heat exchanger or a loop seal superheater.

[0003] The fluidized bed heat exchanger known from Patent Document 1 has a heat exchange chamber (FIG. 1, B) provided with heat transfer tubes and a bypass chamber (FIG. 1, C) parallel thereto without heat exchanger tubes. In this solution, the bypass chamber is the same size as the heat exchange chamber. Since the heat exchanger is composed of only one chamber provided with heat exchanger tubes, there is a problem in sufficiently controlling heat exchange only by controlling the flow air velocity of these two chambers (B, C). Accurate control is required to generate superheated steam with optimized temperature and pressure for the next steam turbine. Steam turbines are usually sensitive to the temperature and pressure of steam.

[0004] A loop-seal superheater with two separate heat exchange chambers is known, for example, from Patent Document 2. A portion of Figure 2a of Patent Document 2 is reproduced herein as Figure 7. The two independently controllable heat exchange chambers provide better control of heat exchange from the fluid medium to the vapor. The two heat exchange chambers are reproduced in Figure 7 and are indicated by reference numerals 410 and 420. As shown in Figure 7, in the prior art, two separate supply chambers 310 and 320 are arranged side by side. Furthermore, each of the supply chambers 310 and 320 supplies the fluid medium to only one of the heat exchange chambers 410 and 420.

[0005] However, in recent years, the efficiency of particle separators used in circulating fluidized bed boilers has improved. This has led to boilers having only particulate separators such as cyclones. There is also an increasing demand for smaller size and capacity distributed boiler units. This also indicates a trend towards smaller particle separators. As the size of the particle separator decreases, there is typically less space available for the heat exchanger. Furthermore, heat exchangers are often manufactured so that the heat exchanger manufacturer (i.e., a person) enters one or more chambers of the heat exchanger, for example, to install protective refractory material on at least part of the heat exchanger wall. Therefore, the individual chambers of the heat exchanger should be large enough to manufacture, i.e., large enough for a person to enter. However, the overall size of the heat exchanger should be sufficiently small. At the same time, the heat exchange from the fluidized medium to the circulating steam should be precisely controllable. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Patent No. 5,184,671 [Patent Document 2] International Publication No. 2018 / 083367 [Overview of the Initiative]

[0007] As needed, an object of the present invention is to provide a heat exchanger suitable for use as a loop-seal heat exchanger for a circulating fluidized bed. Furthermore, even if the overall size is moderately small (at least in one direction), the heat exchanger chamber is appropriately large for a person to enter the heat exchanger. Finally, on the other hand, the heat exchange from the fluidized medium flowing between the heat exchange tubes to the circulating steam flowing within the tubes is precisely controllable.

[0008] To recover heat and control heat exchange, the heat exchanger comprises first and second heat exchanger tubes configured such that the fluid medium flows (runs) through a first supply chamber to the first heat exchanger tube and through a second supply chamber to the second heat exchanger tube. Furthermore, to ensure both supply chambers are sufficiently large, the first supply chamber is configured to supply the fluid medium to the second supply chamber. This saves space compared to the solution in Figure 7, for example, in which two separate supply chambers 310, 320 are arranged side by side and supply the fluid medium to only one of the heat exchange chambers.

[0009] The present invention is disclosed in specific terms in claim 1. The other claims define preferred embodiments. The description describes the function of the heat exchangers of the preferred and other embodiments. [Brief explanation of the drawing]

[0010] [Figure 1] A circulating fluidized bed boiler is shown in a side view. [Figure 2] The different chambers of the heat exchanger are shown in a top view. [Figure 3] The section III-III of the heat exchanger shown in Figure 2 is represented by the cross-section III-III shown in Figure 2. [Figure 4a] Figure 2 shows the cross-section IVa-IVa of the heat exchanger, and the cross-section IVa-IVa is shown in Figure 2. [Figure 4b] The cross-section IVb-IVb of the heat exchanger shown in Figure 2 is represented by the cross-section IVb-IVb shown in Figure 2. [Figure 5]The cross-section VV of the heat exchanger shown in Figure 2 is represented by the cross-section VV shown in Figure 2. [Figure 6a] An embodiment of a nozzle for supplying fluidizing gas is shown. [Figure 6b] An embodiment of a nozzle for supplying fluidizing gas is shown. [Figure 6c] An embodiment of a nozzle for supplying fluidizing gas is shown. [Figure 6d] An embodiment of a nozzle for supplying fluidizing gas is shown. [Figure 7] This presents a solution using prior art.

[0011] To illustrate different views of the embodiment, three orthogonal directions Sx, Sy, and Sz are shown in the figure. Direction Sz is substantially vertical and upward in the use of the heat exchanger. In this method, direction Sz is substantially opposite to gravity. [Modes for carrying out the invention]

[0012] Figure 1 shows a side view of a circulating fluidized bed boiler 1. The circulating fluidized bed boiler 1 comprises a furnace 50, a particle separator 40 (such as a cyclone 41), and a loop seal 5. In Figure 1, the combustion flue gas channel is indicated by reference numeral 20. Typically, the boiler 1 has heat exchangers 26, 28 within the combustion flue gas channel 20, which are configured to recover heat from the combustion flue gas. Some of the heat exchangers may be superheaters 26 configured to superheat steam by recovering heat from the combustion flue gas. Some of the heat exchangers may be economizers 28 configured to heat and / or boil water by recovering heat from the combustion flue gas.

[0013] The furnace 50 is configured to burn several flammable materials. Inert particulate material, such as sand, is also placed in the furnace 50. The mixture of particulate material and flammable material and / or ash is called the fluidized medium. A grate 52 is placed at the bottom of the furnace 50. The grate 52 is configured to supply air to the furnace to fluidize the fluidized medium and to burn at least a portion of the flammable material to form heat, combustion exhaust gas, and ash. In the circulating fluidized bed, the air supply is very strong and the fluidized medium is configured to flow upward within the furnace 50. The grate 52 has grate nozzles 54 for supplying air. The grate 52 restricts a bottom ash channel 56 to remove ash from the furnace 50.

[0014] From the top of the furnace 50, the fluidized medium is transported through the combustion exhaust gas channel 20 to the particle separator 40 to separate the fluidized medium from the gas. From the particle separator 40, for example, the cyclone 41, the separated fluidized medium falls through the channel 60 into the loop seal 5. In the loop seal 5, a layer of fluidized medium is formed. This layer prevents combustion air or fluidized air from flowing in the opposite direction from the furnace 50 to the cyclone 40. When the loop seal 5 does not have a common wall with the furnace 50, the fluidized medium is returned from the loop seal 5 to the furnace 50 via a pipeline 15 configured to transport the fluidized medium from the loop seal 5 to the furnace 50. When the loop seal 5 has a common wall with the furnace 50, the fluidized medium is returned directly from the loop seal 5 to the furnace 50.

[0015] Referring to Figure 1, the heat exchanger 10 is positioned in the loop seal 5. Therefore, since the heat exchanger 10 is suitable for use in a loop seal, it may be alternatively referred to as a loop seal heat exchanger. Furthermore, in contrast to heat exchangers 26 and 28, the heat exchanger 10 is configured to recover heat from particulate material, i.e., a fluidized medium, circulating within the loop seal 5. The channel 60 is connected to the inlet 31 of the heat exchanger 10. The inlet 31 is for introducing the fluidized medium into the heat exchanger 10. Therefore, the heat exchanger 10 is suitable for recovering heat from the particulate fluidized medium of the fluidized bed boiler 1.

[0016] Referring to FIGS. 2 to 5, the heat exchanger 10 has walls (including walls 510, 520, 530, 540, and 550) that divide the heat exchanger 10 into different chambers (including 100, 310, 320, 410, 420, and 200). The chambers have a floor (including 102, 202, 312, 322) and a ceiling (shown without a reference number).

[0017] Here, the term "chamber" refers to the space within the heat exchanger 10 that is separated from other chambers by walls, i.e., walls that are vertical during use. As will be described in detail below, the walls separating a chamber from adjacent chambers need not extend the full length from the floor to the ceiling of the chamber.

[0018] Referring to FIG. 2, the heat exchanger 10 has a first heat exchanger tube 810 and a second heat exchanger tube 820. The purpose of the heat exchanger tubes 810, 820 is to recover heat from the hot fluid medium flowing within the heat exchanger 10.

[0019] The heat exchanger 10 has a first supply chamber 310 configured to supply a fluid medium to the first heat exchanger tube 810. The heat exchanger 10 has a second supply chamber 320 configured to supply a fluid medium to the second heat exchanger tube 820. The purpose of the supply chambers 310, 320 is to control the amount of the fluid medium flowing through the first heat exchanger tube 810 on the one hand and the second heat exchanger tube 820 on the other hand. Further, in order to control heat exchange, the first and second heat exchanger tubes 810, 820 are not arranged in the same chamber of the heat exchanger 10. In other words, the first and second heat exchanger tubes 810, 820 are arranged at different positions of the heat exchanger 10. More specifically, the first heat exchanger tube 810 is arranged only on the first side surface of the plane P, and the second heat exchanger tube 820 is arranged only on the second opposite side surface of the plane P. Preferably, the heat exchanger tubes 810, 820 are arranged relative to the plane P configured vertically during use; that is, they are arranged only on both opposite sides of the plane P. Preferably, the first heat exchanger tube 810 is arranged only on the first side surface, and the second heat exchanger tube 820 is arranged only on the second side surface of the plane P that intersects at least one of the first supply chamber 310 and the second supply chamber 320 and is configured vertically during use. More preferably, the first heat exchanger tube 810 is arranged only on the first side surface, and the second heat exchanger tube 820 is arranged only on the second side surface of the plane P that intersects both the first supply chamber 310 and the second supply chamber 320.

[0020] In FIG. 2, at least a part of the first supply chamber 310 is arranged between the first heat exchanger tube 810 and the second heat exchanger tube 820. However, the tubes 810, 820 do not need to fill the heat exchange chambers 410, 420. In such a case, even if the first supply chamber 310 is arranged between the heat exchange chambers 410, 420 each provided with the heat exchanger tubes 810, 820, it is not necessary that even a part of the first supply chamber 310 be arranged between the first heat exchanger tube 810 and the second heat exchanger tube 820.

[0021] The first supply chamber 310 is configured to supply a fluid medium to the second supply chamber 320. As shown by the arrows in Figure 2, the first supply chamber 310 has an outlet 316 for discharging the fluid medium from the first supply chamber 310 to the second supply chamber 320.

[0022] This has the effect that the width W310 of the first supply chamber 310 in direction Sy (and optionally the width of the second supply chamber 320) remains larger than if the supply chambers 310 and 320 were arranged adjacent to each other in direction Sy. Furthermore, since the purpose of the heat exchanger tubes 810 and 820 is to recover heat, it is preferable that the heat exchanger tubes 810 and 820 be designed to be relatively long in at least one direction indicated by Sx in Figure 2. Thus, even if the size of the heat exchanger 10 should be reduced, the length of at least the heat exchange chambers 410 and 420 should be kept as long as possible for efficient heat recovery. Thus, typically, there is available space in the Sx direction, especially for such chambers that do not contain heat exchanger tubes. This saves space and allows for precise control of heat transfer.

[0023] Preferably, the supply of the fluid to the heat exchanger tubes 810 and 820 can be controlled independently of each other. Therefore, in one embodiment, the first supply chamber 310 is configured to supply the fluid only to the first heat exchanger tube 810 and the second supply chamber 320. Furthermore, in one embodiment, the second supply chamber 320 is configured to supply the fluid only to the second heat exchanger tube 820.

[0024] Since the first supply chamber 310 is configured to supply the fluid medium to the second supply chamber 320, in a preferred embodiment, the second supply chamber 320 is configured to receive the fluid medium only from the first supply chamber 310. For example, in one embodiment, the inlet chamber 100 is configured to supply the fluid medium to the first supply chamber 310, and the inlet chamber 100 is configured to supply the fluid medium to the second supply chamber 320 only through the first supply chamber 310. As will be detailed below, the inlet chamber 100 may also be configured to supply the fluid medium to the bypass chamber 200.

[0025] The white arrows in Figure 2 indicate outlets for the fluid medium in different chambers (104, 314, 414, 434, 316, 324, 424, 444, 106, 204). In Figure 2, such arrows without overlapping lines (i.e., the arrows for outlets 314, 324, 434, 444, and 204) relate to the upper outlets of the chambers. In Figure 2, such arrows with overlapping lines (i.e., the arrows for outlets 104, 106, 316, 414, and 424) relate to the lower outlets of the chambers. The outlets may be formed as openings in the walls. Alternatively, the lower outlets of the chambers may be formed by a wall that extends downward from the ceiling but not to the floor level. Correspondingly, the upper outlets of the chambers may be formed by a wall that extends upward from the floor but not to the ceiling level.

[0026] During use, the first portion of the fluid medium flows between the first heat exchanger tubes 810. The second portion of the fluid medium flows between the second heat exchanger tubes 820. The third portion of the fluid medium flows through the bypass chamber 200, bypassing both the first and second heat exchanger tubes 810 and 820.

[0027] Referring to Figures 1 and 2, the fluid enters the heat exchanger 10 via an inlet 31 located within the inlet chamber 100. From the inlet chamber 100, the fluid (i.e., the first and second portions of the fluid) may enter the first supply chamber 310 through an outlet 104 (see Figure 2). This is also indicated by arrow A12 in Figure 3. In addition or alternatively, from the inlet chamber 100, the fluid (i.e., the third portion of the fluid) may enter the bypass chamber 200 through an outlet 106 (see Figure 2). This is also indicated by arrow A3 in Figure 3. As shown in Figure 2, the inlet chamber 100 is configured to supply the fluid only to the bypass chamber 200 and the first supply chamber 310. Naturally, as described above, the second portion of the fluid flows through the first supply chamber 310 to the second supply chamber 320.

[0028] From the first supply chamber 310, the first portion of the fluidized medium flows through the outlet 314 (see Figure 2) to the first heat exchange chamber 410. In the first heat exchange chamber 410, the fluidized medium flows through the first heat exchanger tubes 810 to the outlet 414, thereby heating the heat transfer medium (typically steam) flowing within the first heat exchanger tubes 810. The fluidized medium flows through the outlet 414 to the first outlet chamber 430, through the outlet 434 to pipeline 15, and finally back to the furnace 50. If the heat exchanger 10 has a common wall with the furnace 50, the outlet 434 may open directly to the furnace 50. Alternatively, the outlet 414 may open directly to the furnace 50, thereby omitting the first outlet chamber 430.

[0029] Regarding the circulation of the second portion of the fluid medium, the second portion flows from the first supply chamber 310 through the outlet 316 to the second supply chamber 320 (see Figure 2). From the second supply chamber 320, the second portion of the fluid medium flows through the outlet 324 to the second heat exchange chamber 420. In the second heat exchange chamber 420, the fluid medium flows through the second heat exchanger tubes 820 to the outlet 424, thereby heating the heat transfer medium (typically steam) flowing within the second heat exchanger tubes 820. The fluid medium flows through the outlet 424 to the second outlet chamber 440, through the outlet 444 to pipeline 15, and finally back to the furnace 50. If the heat exchanger 10 has a common wall with the furnace 50, the outlet 444 may open directly to the furnace 50. Alternatively, the outlet 424 may open directly to the furnace 50, thereby omitting the second outlet chamber 440.

[0030] As detailed above, heat is therefore recovered from both the first and second portions of the fluid medium by the first and second heat exchanger tubes 810 and 820, respectively. However, in some cases, it is not necessary to recover heat from the fluid medium, or it is necessary to reduce the amount of heat exchange. Therefore, a third portion of the fluid medium may bypass both the first and second heat transfer tubes 810 and 820. For the circulation of the third portion of the fluid medium, from the bypass chamber 200, the fluid medium can exit to pipeline 15 through outlet 204. Alternatively, outlet 204 may open directly to the furnace 50.

[0031] One or more chambers of the heat exchanger 10 may be provided with an ash removal channel 19. The purpose of the ash removal channel is to remove bottom ash from the heat exchanger 10. Another purpose of the ash removal channel is to discharge the fluid from the heat exchanger for maintenance purposes. If bottom ash is removed from the heat exchanger 10 during operation on it, the hot bottom ash may be transported to an ash cooler 600 (see Figure 5) to recover heat from the ash.

[0032] Therefore, in one embodiment, the heat exchanger 10 is provided in the loop seal 5 of the circulating fluidized bed boiler 1. Referring to Figure 1, according to one embodiment, the circulating fluidized bed boiler 1 has a furnace 50, a particle separator 40 (such as a cyclone 41) configured to separate the fluidized medium from the combustion exhaust gas that can be received from the furnace 50, and a loop seal 5 configured to receive the fluidized medium separated from the particle separator 40. In this embodiment, the loop seal 5 includes the heat exchanger 10 as described above and as disclosed below.

[0033] In an embodiment of the circulating fluidized bed boiler 1, the heat exchanger 10 is arranged such that at least a portion of the separated fluidized medium flows through a first supply chamber 310. Note that another portion of the fluidized medium may flow through a bypass chamber. The fluidized medium may flow through only one of the chambers 310, 200 at a time. However, in a typical use, a portion of the fluidized medium flows into the first supply chamber 310, while another portion of the fluidized medium flows into the bypass chamber 200. Furthermore, the first portion of the separated fluidized medium is configured to flow from the first supply chamber 310 to the first heat exchanger tube 810. Furthermore, the second portion of the separated fluidized medium is configured to flow from the first supply chamber 310 to the second supply chamber 320, and through the second supply chamber 320 to the second heat exchanger tube 820. As described above, the first portion of the separated fluid medium is configured to flow from the first supply chamber 310 to the first heat exchanger tube 810 without flowing through the second supply chamber 320. As described above, the third portion of the separated fluid medium is configured to flow into the bypass chamber 200, bypassing both the first and second heat exchanger tubes 810 and 820.

[0034] An outlet 316 is provided in the heat exchanger 10, and in order to guide the fluid medium as described above, in one embodiment, the heat exchanger 10 includes a first wall 510 that limits the first supply chamber 310 and the second supply chamber 320. That is, the first wall 510 separates the upper part of the first supply chamber 310 from the upper part of the second supply chamber 320. The first wall 510 is shown in Figures 2, 3 and 4a. The first wall 510 is vertical when in use. As shown in Figures 3 and 4a, the first wall 510 has a first lower edge 512. When the heat exchanger is in use, the first lower edge 512 is positioned at a vertical level higher than the floors 312, 322 or floors 312, 322 of the first supply chamber 310 and the second supply chamber 320. The floor is shown in Figure 3. More precisely, if floors 312 and 322 are positioned at the same vertical level, the first lower edge 512 is positioned at a higher vertical level. However, if floors 312 and 322 are not positioned at the same vertical level, the first lower edge 512 is positioned at a higher vertical level than these two higher floors. In this way, the first supply chamber 310 is configured to supply a fluid medium to the second supply chamber 320 from between the first lower edge 512 of the first wall 510 and the floor(s)(312, 322) of the first and second supply chambers 310 and 320. The first lower edge 512 does not need to be as wide as the supply chambers(310, 320). In contrast, the first lower edge may be the upper edge of an opening in the first wall 510.

[0035] Preferably, the floors 312, 322 of the first supply chamber 310 and the second supply chamber 320 are located at the same vertical level. Furthermore, preferably, the first lower edge 512 of the first wall 510 is not located above any part of the first wall 510. That is, if the first lower edge 512 is the upper edge of an opening in the wall 510, the opening extends to the level of the floor (312, 322), or, if they are not at the same level, to the higher level of the floor. This has the effect that the fluid can easily flow from the first supply chamber 310 to the second supply chamber 320.

[0036] Throughout this explanation, please note that the term "vertical level" refers to the vertical position, i.e., altitude. For example, the horizontal plane is positioned at the vertical level. Therefore, the vertical level defines the position of the horizontal plane.

[0037] To control the flow of the fluid medium through various chambers, and in this way to control the heat exchange from the fluid medium to steam, the heat exchanger 10 is equipped with nozzles for fluidizing the fluid medium.

[0038] Referring to Figure 3, preferably, the heat exchanger 10 has primary first nozzles 911. The primary first nozzles 911 are positioned at a vertical level lower than the first lower edge 512 of the first wall 510 when in use. That is, the primary first nozzles 911 are positioned below the first lower edge 512 of the first wall 510 when in use, but not necessarily directly below it. Furthermore, the primary first nozzles 911 are located in the first supply chamber 310. Furthermore, the primary first nozzles 911 are configured to fluidize the fluid medium within the first supply chamber 310. Similarly, the heat exchanger 10 has primary second nozzles 921. The primary second nozzles 921 are positioned at a vertical level lower than the first lower edge 512 of the first wall 510 when in use. The primary second nozzles 921 are located in the second supply chamber 320. The two nozzles 921 are configured to fluidize the fluid medium in the second supply chamber 320. By using the nozzles 911 and 921, the fluid medium is fluidized to flow from chamber 310 to chamber 320 and through chambers 310 and 320.

[0039] By controlling the airflow through these nozzles 911 and 921, it is possible to control how the fluid medium flowing into the first supply chamber 310 is divided into a first portion that flows through tube 810 and a second portion that flows through tube 820.

[0040] Therefore, in one embodiment of a circulating fluidized bed boiler 1 having a heat exchanger 10, the amount of fluidized air supplied through a single-stage 1 nozzle 911 is configured to be controlled independently of the amount of fluidized air supplied through a single-stage 2 nozzle 921. Air control can be achieved, for example, by controlling the nozzles (911, 921) and / or by controlling baffle plates that affect the airflow to the nozzles (911, 921). For example, a first baffle may control the airflow to nozzle 911, and a second baffle may control the airflow to nozzle 921. A control unit may be configured to control the nozzles and / or baffles(s) accordingly.

[0041] However, it should be noted that, due to the outlet 316 between the first and second supply chambers 310, 320 (see Figure 2; or Figure 3, the outlet is not shown and remains below the edge 512), some of the air from the first nozzle 911 is readily directed to the second supply chamber 320, and similarly, some of the air from the second nozzle 921 is readily directed to the first supply chamber 310. This makes precise control of the fluid flow considerably more difficult. However, the nozzles 911, 921 are advantageously positioned below the first lower edge 512 to provide transport of the fluid through the outlet 316.

[0042] To provide more precise control, one embodiment of the heat exchanger 10 includes a secondary first nozzle 912 (see Figure 3). The secondary first nozzle 912 is positioned at a vertical level higher than the first lower edge 512 of the first wall 510 when in use. That is, the secondary first nozzle 912 is positioned above the first lower edge 512 of the first wall 510 when in use, but does not necessarily have to be positioned directly above it. The secondary first nozzle 912 is located within the first supply chamber 310. The secondary first nozzle 912 is configured to fluidize the fluidizing medium within the first supply chamber 310. Because the secondary first nozzle 912 is positioned at a vertical level higher than the first lower edge 512 of the first wall 510, a small amount of fluidizing air from these nozzles 912 will flow into the second supply chamber 320, if any.

[0043] In a corresponding manner, in one embodiment, the heat exchanger 10 has a secondary second nozzle 922. The secondary second nozzle 922 is positioned at a vertical level higher than the first lower edge 512 of the first wall 510 when in use. The secondary second nozzle 922 is located within a second supply chamber 320. The secondary second nozzle 922 is configured to fluidize the fluidizing medium within the second supply chamber 320. Because the secondary second nozzle 922 is positioned at a vertical level higher than the first lower edge 512 of the first wall 510, a small amount of fluidizing air from these nozzles flows into the first supply chamber 310, if any.

[0044] By controlling the airflow through these nozzles 912 and 922, it is possible to control how the fluid medium flowing into the first supply chamber 310 is divided into a first portion that flows through tube 810 and a second portion that flows through tube 820.

[0045] Therefore, in an embodiment of a circulating fluidized bed 1 having a heat exchanger 10, the amount of fluidized air supplied through the secondary first nozzle 912 is configured to be controlled independently of the amount of fluidized air supplied through the secondary second nozzle 922. Preferably, at the same time, the amount of fluidized air supplied through the single-stage first nozzle 911 is configured to be controlled independently of the amount of fluidized air supplied through the single-stage second nozzle 921. The aforementioned provision applies to controlling the airflow through the nozzles by using nozzles and / or baffles / multiple baffles and / or controllers.

[0046] It has been found that when the flow of the fluid medium is controlled so that the airflow through the secondary first nozzle 912 and / or secondary second nozzle 922 is low, the fluid medium tends to enter these nozzles 912, 922. To prevent the fluid medium from entering the nozzles and, in some cases, from clogging them, the nozzles can be closed from above. Thus, in one embodiment, the secondary first nozzle 912 is closed from above to prevent the fluid medium from entering the secondary first nozzle 912, and the secondary second nozzle 922 is closed from above to prevent the fluid medium from entering the secondary second nozzle 922.

[0047] Figure 3 shows a curved cover or roof for nozzles 912, 922 to prevent the flow of fluid into the nozzles 912, 922. This configuration is shown in more detail in Figure 6a, where the curved cover or roof 951 is indicated by its own reference number, where the dotted line indicates the airflow. The nozzles can also be closed from above in other ways. For example, in the embodiment of Figure 6b, the nozzle has a curved shape, forming a U-shape that opens downwards. Thus, the curved pipe portion 952 closes the nozzle from above (i.e., from above). Furthermore, as shown in Figure 6c, a flat cover or roof 953 may be sufficient to prevent the fluid from entering the nozzle. Furthermore, many portions of the cover or roof 951 may be substantially vertical, as shown in Figure 6d.

[0048] If necessary, the first nozzle 911 can also be closed from above to prevent the fluid medium from entering the first nozzle 911. If necessary, the second nozzle 921 can also be closed from above to prevent the fluid medium from entering the second nozzle 921.

[0049] As described above, in the embodiment, the second supply chamber 320 has an outlet 324 for supplying a fluid to the second heat exchange chamber 420 (see Figures 2 and 3). Preferably, in this case, the outlet 324 of the second supply chamber 320 is positioned at a vertical level higher than the first lower edge 512 when in use. See Figure 4a. More specifically, preferably, the entire outlet 324 is positioned at a vertical level higher than the first lower edge 512. The outlet 324 may be limited by the upper edge of a wall that separates the lower part of the second supply chamber 320 from the second heat exchange chamber 420. The curved arrow A2 in Figures 4a and 43 indicates the flow of fluid over such a wall through the outlet 324. Positioning the outlet 324 above the first lower edge 512 has the technical effect of the second supply chamber 320 functioning as a gas lock, as part of which prevents the fluid medium from flowing in the wrong, opposite direction (i.e., not from chamber 420 through chamber 320 to chamber 310).

[0050] Preferably, the outlet 324 of the second supply chamber 320 is also positioned at a higher vertical level than the secondary second nozzle 922. This has the effect of allowing for more reliable use of the secondary second nozzle 922 to control the flow of the fluid medium. Thus, the fluid medium does not escape from the second supply chamber through the outlet 324 before being fluidized by the air from the second nozzle 922.

[0051] Referring to Figures 3 and 4b, in one embodiment, the heat exchanger 10 has a second wall 520 that restricts the inlet chamber 100 and the first supply chamber 310. The second wall 520 is vertical when in use. The second wall 520 has a second lower edge 522 that is positioned at a vertical level higher than the floors 312, 102 or the floors 312, 102 of the inlet chamber 100 and the first supply chamber 310. More precisely, if the floors 312, 102 are positioned at the same vertical level, the second lower edge 522 is positioned at a higher vertical level. However, if the floors 312, 102 are not positioned at the same vertical level, the second lower edge 522 is positioned at a vertical level higher than these two higher floors. In this method, the inlet chamber 100 is configured to supply the fluid medium to the first supply chamber 310 from between the second lower edge 522 of the second wall 520 and the floor (102, 312) of the inlet chamber 100 and the first supply chamber 310. The second lower edge 522 does not need to be as wide as the first supply chamber 310 or the inlet chamber 100. In contrast, the second lower edge 522 may be the upper edge of an opening in the second wall 520.

[0052] Preferably, the floors 312, 102 of the first supply chamber 310 and the inlet chamber 100 are positioned at the same vertical level. Furthermore, preferably, the second lower edge 522 of the second wall 520 is not positioned above any part of the second wall 520. That is, if the second lower edge 522 is the upper edge of the opening, the opening extends to the floor level (or the higher level of the floor). This has the effect that the fluid can easily flow from the inlet chamber 100 to the first supply chamber 310.

[0053] If the heat exchanger has both a second wall 520 and a secondary first nozzle 912, preferably the secondary first nozzle 912 is positioned at a vertical level higher than the second lower edge 522 of the second wall 520. This has the effect of preventing the air blown in by the secondary first nozzle 912 from easily flowing into the inlet chamber 100 and / or through the inlet 31 to the channel 60 (see Figures 3 and 1).

[0054] Preferably, if the heat exchanger has both a first wall 510 and a second wall 520, these walls are parallel. Furthermore, preferably, the first lower edge 512 is not positioned at a lower vertical level than the second lower edge 522 during use. This ensures that the first supply chamber 310 functions properly because there is a tendency for the fluid to flow from the first supply chamber 310 to the second supply chamber 320 rather than from the first supply chamber 310 back to the inlet chamber 100. In Figure 3, these edges 512, 522 are positioned at substantially the same vertical level.

[0055] In one embodiment, the first supply chamber 310 is located between the inlet chamber 100 and the second supply chamber 320. See Figure 2. As mentioned above, for efficient heat recovery, the lengths of at least the heat exchange chambers 410, 420 should be kept as long as possible. Therefore, typically, there is space available in this direction in particular for these chambers 100, 310, 320. To clarify, in a preferred embodiment, the inlet chamber 100, the first supply chamber 310, and the second supply chamber 320 are located next to the first heat exchange chamber 410, which has the first heat exchanger tube 810. Here, the term “next to” means that there is only one vertical wall between the two chambers that are adjacent to each other. Preferably, the inlet chamber 100, the first supply chamber 310, and the second supply chamber 320 are also located next to the second heat exchange chamber 420, which has the second heat exchanger tube 820.

[0056] In other words, in one embodiment, the heat exchanger 10 has a third wall 530 that restricts the first heat exchange chamber 410 and a fourth wall 540 that restricts the second heat exchange chamber 420. These walls 530, 540 are shown, for example, in Figures 2, 4a, and 4b. In use, the third wall 530 is vertical and the fourth wall 540 is vertical. Furthermore, in the embodiment of Figure 2, the third wall 530 is parallel to the fourth wall 540. Furthermore, in Figure 2, at least a portion of the first wall 510 is located between the third wall 530 and the fourth wall 540. Note that the first wall may extend vertically longer than the walls 530, 540. In one embodiment, the first wall 510 is perpendicular to the third wall 530. Also, if a second wall 520 is present, preferably at least a portion of it is located between the third wall 530 and the fourth wall 540. In one embodiment, the second wall 520 is perpendicular to the third wall 530. In one embodiment, a portion of the third wall 530 restricts the first supply chamber 310. In one embodiment, a portion of the third wall 530 restricts the second supply chamber 320. In one embodiment, a portion of the fourth wall 540 restricts the first supply chamber 310. In one embodiment, a portion of the fourth wall 540 restricts the second supply chamber 320.

[0057] More preferably, the inlet chamber 100 is located between the first supply chamber 310 and the bypass chamber 200. In this case, the bypass chamber 200 may be located next to the first heat exchange chamber 410. In addition or alternatively, the bypass chamber 200 may be located next to the second heat exchange chamber 420. Similarly, in the embodiment of Figure 2, a portion of the third wall 530 also restricts the bypass chamber 200. Furthermore, a portion of the fourth wall 540 also restricts the bypass chamber 200.

[0058] To enhance the flow of material from the inlet chamber 100 to the bypass chamber 200 and the first inlet chamber 310, in one embodiment, the heat exchanger 10 has a third nozzle 930 located below the inlet chamber 100 and configured to fluidize the material within the inlet chamber 100. See Figure 3.

[0059] Preferably, the width W310 of the first supply chamber 310 is at least 500 mm. This allows, for example, an operator to enter the first supply chamber 310 during its manufacture. Here, the width W310 is determined in a direction parallel to the direction of the minimum distance between the first heat exchanger tube 810 and the second heat exchanger tube 820. If the heat exchanger has third and fourth walls 530, 540 and portions of the walls 530, 540 restrict the first supply chamber 310, the width W310 is limited to between the third wall 530 and the fourth wall 540.

[0060] Regarding the upper limit of the width W310, there is no technical reason other than the size of the heat exchanger 10 relative to the upper limit. However, if the width W310 is very large, such that the first supply chamber 310 can be divided into two parts side by side in the direction of the width W310 so that a person can enter the component, there is no technical reason to guide the fluid medium through the first supply chamber 310 to the second supply chamber 320. Instead, the first and second supply chambers 310, 320 can be arranged adjacent to each other, as shown in Figure 7, and the fluid medium can be arranged to flow directly into each from the inlet chamber 100. Furthermore, typically, the width and length of the inlet chamber 100 are equal to the width and length of the channel 60 in the inlet 31 (see Figure 6). Furthermore, for manufacturing reasons, the width W310 is preferably equal to the width of the inlet chamber 100. For these reasons, the width W310 can be, for example, 500 mm to 1600 mm.

[0061] For similar reasons, the overall width W10 of the heat exchanger 10, which is determined in a direction parallel to the direction of the minimum distance between the first heat exchanger tube 810 and the second heat exchanger tube 820, can be, for example, at least 4000 mm. The width W10 can be, for example, 4000 mm to 7700 mm.

[0062] As described above, the fluid medium can enter the first heat exchange chamber 410 from the first supply chamber 310 (see Figure 2) through the outlet 314. Preferably, the outlet 314 of the first supply chamber 310 is positioned at a vertical level higher than the second lower edge 522 of the second wall 520 when in use (see Figure 4b). More specifically, preferably, the entire outlet 314 is positioned at a vertical level higher than the second lower edge 522. The outlet 314 may be limited by the upper edge of a wall that separates the lower part of the first supply chamber 310 from the first heat exchange chamber 410. The curved arrow A1 in Figures 4b and 43 indicates the flow of the fluid medium over such a wall through the outlet 314. Positioning the outlet 314 above the second lower edge 522 has the technical effect of allowing the first supply chamber 310 to function as a gas lock, preventing, in part, the fluid medium from flowing in the wrong, opposite direction (i.e., not from chamber 410 through chamber 310 to chamber 100).

[0063] In addition, or alternatively, preferably, the outlet 314 of the first supply chamber 310 is positioned at a vertical level higher than the first lower edge 512 of the first wall 510 when in use (see Figure 3). More specifically, preferably, the entire outlet 314 is positioned at a vertical level higher than the first lower edge 512. Positioning the outlet 314 above the first lower edge 512 has the technical effect of allowing for better control of the flow of the medium.

[0064] Preferably, the outlet 314 of the first supply chamber 310 is positioned at a vertical level higher than the secondary first nozzle 912 during use (see Figure 3). This has the effect of allowing the fluid medium in the first supply chamber 310 to fluidize before the secondary first nozzle 912 escapes into the first heat exchange chamber 410. In this way, this improves the control of the material flow.

[0065] Referring to Figures 2 and 3, in one embodiment, the heat exchanger 10 has a fifth wall 550 that separates the bypass chamber 200 and the inlet chamber 100. In this configuration, the fifth wall 550 separates at least the upper part of the bypass chamber 200 from the inlet chamber 100. As described above, the inlet chamber 100 has an inlet 31 for the fluidized medium. The fifth wall 550 has a fifth lower edge 552 (see Figure 3). When in use, the fifth lower edge 552 is positioned at a vertical level higher than the floors 202, 102 or multiple floors 202, 102 of the inlet chamber 100 and the bypass chamber 200. In this way, the inlet chamber 100 is configured to supply the fluidized medium to the bypass chamber 200.

[0066] More precisely, if floors 102 and 202 are located at the same vertical level, the fifth lower edge 552 is located at a higher vertical level. However, if floors 102 and 202 are not located at the same vertical level, the fifth lower edge 552 is located at a higher vertical level than the higher of the two floors. In this configuration, the inlet chamber 100 is configured to supply a fluid to the bypass chamber 200 from between the fifth lower edge 552 of the fifth wall 550 and the floor(s) (102, 202) of the inlet chamber 100 and the bypass chamber 200. The fifth lower edge 552 does not need to be as wide as the inlet chamber 100 or the bypass chamber 200. In contrast, the fifth lower edge 552 may be the upper edge of an opening in the fifth wall 550.

[0067] Preferably, the floors 102, 202 of the inlet chamber 100 and the bypass chamber 200 are positioned at the same vertical level. Furthermore, preferably, the fifth lower edge 552 of the fifth wall 550 is not positioned above any part of the fifth wall 550. That is, if the fifth lower edge 552 is the upper edge of the opening, the opening extends to the level of the floor (or higher than the floor). This has the effect of allowing the fluid to flow easily from the inlet chamber 100 to the bypass chamber 200.

[0068] The bypass chamber 200 is suitable for bypassing the first and second heat exchanger tubes (810, 820) of the heat exchanger 10. This has the effect of being able to control the amount of fluid medium from which heat is recovered. To control the flow of fluid medium through the bypass chamber 200, the heat exchanger 10 has a fourth nozzle 940 (see Figure 3) located at the bottom of the bypass chamber 200. The fourth nozzle 940 is configured to fluidize the fluid medium within the bypass chamber 200.

[0069] Even if the nozzles 911 and 912 in the first supply chamber 310 affect the flow of the medium to the first heat exchanger tube 810, preferably the flow of the fluidized medium in the first heat exchange chamber 410 is also enhanced by the fluidized gas. Therefore, in one embodiment, the heat exchanger has a fifth nozzle 950 located at the bottom of the first heat exchange chamber 410. The fifth nozzle 950 is configured to fluidize the fluidized medium in the first heat exchange chamber 410. Refer to Figures 4a, 4b, and 5.

[0070] Even if the nozzles 921 and 922 in the second supply chamber 320 affect the flow of the medium to the second heat exchanger tube 820, preferably the flow of the fluid medium in the second heat exchange chamber 420 is also enhanced by the fluid gas. Therefore, in one embodiment, the heat exchanger has a sixth nozzle 960 located at the bottom of the second heat exchange chamber 420. The sixth nozzle 960 is configured to fluidize the fluid medium within the second heat exchange chamber 420. See Figures 4a and 4b.

[0071] For similar reasons, in one embodiment, the heat exchanger has a seventh nozzle 970 (see Figure 5) configured to fluidize a fluid medium in a first outlet chamber 430. For similar reasons, in one embodiment, the heat exchanger has an eighth nozzle (not shown) configured to fluidize a fluid medium in a second outlet chamber 440.

Claims

1. A heat exchanger suitable for recovering heat from the fluidized medium of a fluidized bed boiler, wherein the heat exchanger is: - The first heat exchanger tube, - The second heat exchanger tube, - A first supply chamber configured to supply a fluid medium to the first heat exchanger tube, - A second supply chamber configured to supply a fluid medium to the second heat exchanger tube, It has, - The first heat exchanger tube is positioned only on the first side of a plane that intersects with the first supply chamber and is configured to be vertical during use, and the second heat exchanger tube is positioned only on the second side of the plane, - The first supply chamber is configured to supply a fluid medium to the second supply chamber. - The first supply chamber is configured to supply the fluid medium only to the first heat exchanger tube and the second supply chamber. - The second supply chamber is configured to supply the fluid medium only to the second heat exchanger tube. heat exchanger.

2. - A first wall that restricts the first supply chamber and the second supply chamber, wherein the first wall is - When in use, it has a first lower edge that is positioned at a vertical level higher than the floor of one or more of the first supply chambers and the second supply chambers, - The first supply chamber is configured to supply a fluid medium to the second supply chamber from between the first lower edge of the first wall and the floor of the first and second supply chambers. The heat exchanger according to claim 1.

3. - A single nozzle is provided, which is positioned at a vertical level lower than the first lower edge of the first wall and within the first supply chamber during use, and is configured to fluidize the fluid medium within the first supply chamber. - A single-stage nozzle is provided, which is positioned at a vertical level lower than the first lower edge of the first wall and within the second supply chamber, and is configured to fluidize the fluid medium within the second supply chamber when in use. The heat exchanger according to claim 2.

4. - A secondary first nozzle is positioned at a vertical level higher than the first lower edge of the first wall and within the first supply chamber during use, and is configured to fluidize the fluid medium within the first supply chamber. - A secondary second nozzle is positioned within the second supply chamber at a vertical level higher than the first lower edge of the first wall during use, and configured to fluidize the fluid medium within the second supply chamber. The heat exchanger according to claim 2.

5. - The second heat exchanger tube is placed in the second heat exchange chamber of the heat exchanger. - The second supply chamber has an outlet for supplying a fluid medium to the second heat exchange chamber. - The outlet of the second supply chamber is positioned at a vertical level higher than the first lower edge when in use. The heat exchanger according to claim 2.

6. - A first wall that restricts the first supply chamber and the second supply chamber, - A second wall that restricts the inlet chamber and the first supply chamber, and - An inlet for receiving a fluid medium, the inlet having an inlet located within the inlet chamber, the second wall being - A second lower edge portion is positioned at a vertical level higher than the floor of one or more of the inlet chamber and the first supply chamber, - The inlet chamber is configured to supply a fluid medium to the first supply chamber from between the second lower edge of the second wall and the floor of the inlet chamber and the first supply chamber. The heat exchanger according to claim 1.

7. The first obstacle mentioned above is, - When in use, it has a first lower edge that is positioned at a vertical level higher than the floor of one or more of the first supply chambers and the second supply chambers, - The first supply chamber is configured to supply a fluid medium to the second supply chamber from between the first lower edge of the first wall and the floor of the first and second supply chambers, - The second wall is parallel to the first wall, - The first lower edge is not positioned at a vertical level lower than the second lower edge. The heat exchanger according to claim 6.

8. - The first supply chamber is located between the inlet chamber and the second supply chamber. The heat exchanger according to claim 6.

9. - The first heat exchanger tube is placed in the first heat exchange chamber of the heat exchanger. - The first supply chamber has an outlet for supplying a fluid medium to the first heat exchange chamber of the heat exchanger. - The outlet of the first supply chamber is positioned at a vertical level higher than the first lower edge when in use, and / or - The outlet of the first supply chamber is positioned at a vertical level higher than the second lower edge when in use. The heat exchanger according to claim 7.

10. - A third wall that limits the first heat exchange chamber equipped with the first heat exchanger tube, - A fourth wall that limits the second heat exchange chamber, which is equipped with the second heat exchange tube, - The third wall is parallel to the fourth wall, - At least a portion of the first wall is positioned between the third wall and the fourth wall. The heat exchanger according to claim 2.

11. - A fifth wall that restricts the bypass chamber and the inlet chamber, wherein the fifth wall is - When in use, it has a fifth lower edge which is positioned at a vertical level higher than the floor of one or more of the inlet chamber and the bypass chamber, - The inlet chamber is configured to supply a fluid to the bypass chamber, - The bypass chamber is suitable for bypassing the first and second heat exchanger tubes of the heat exchanger. The heat exchanger according to claim 1.

12. A circulating fluidized bed boiler, - The furnace, - A particle separator, such as a cyclone, configured to separate a fluid medium from the combustion exhaust gas that can be received from the furnace, - A loop seal configured to receive the fluidized medium separated from the particle separator, comprising a loop seal having a heat exchanger according to any one of claims 1 to 11, wherein the heat exchanger is - At least a portion of the separated fluid medium is configured to flow through the first supply chamber, - The first portion of the separated fluid medium is configured to flow from the first supply chamber to the first heat exchanger tube, - The second portion of the separated fluid medium is configured to flow from the first supply chamber to the second supply chamber, and through the second supply chamber to the second heat exchanger tube. It is configured in such a way. Circulating fluidized bed boiler.

13. A circulating fluidized bed boiler, - The furnace, - A particle separator such as a cyclone configured to separate a fluid medium from the combustion exhaust gas that can be received from the furnace, - A loop seal configured to receive the fluidized medium separated from the particle separator, comprising a loop seal having the heat exchanger described in claim 3, wherein the heat exchanger is - At least a portion of the separated fluid medium is configured to flow through the first supply chamber, - The first portion of the separated fluid medium is configured to flow from the first supply chamber to the first heat exchanger tube, - The second portion of the separated fluid medium is configured to flow from the first supply chamber to the second supply chamber, and through the second supply chamber to the second heat exchanger tube, - The amount of fluidized air supplied through the first nozzle is controlled independently of the amount of fluidized air supplied through the second nozzle. It is configured in such a way. Circulating fluidized bed boiler.

14. A circulating fluidized bed boiler, - The furnace, - A particle separator such as a cyclone configured to separate a fluid medium from the combustion exhaust gas that can be received from the furnace, - A loop seal configured to receive the fluidized medium separated from the particle separator, comprising a loop seal having the heat exchanger described in claim 4, wherein the heat exchanger is - At least a portion of the separated fluid medium is configured to flow through the first supply chamber, - The first portion of the separated fluid medium is configured to flow from the first supply chamber to the first heat exchanger tube, - The second portion of the separated fluid medium is configured to flow from the first supply chamber to the second supply chamber, and through the second supply chamber to the second heat exchanger tube, - The amount of fluidized air supplied through the secondary first nozzle is configured to be controlled independently of the amount of fluidized air supplied through the secondary second nozzle. Circulating fluidized bed boiler.

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