Heat exchanger and circulating fluidized bed boiler

Abstract

A heat exchanger (10) adapted to recover heat from bed material of a fluidized bed boiler (1). The heat exchanger (10) comprises first and second heat exchanger tubes (810, 820) and first and second feed chambers (310, 320) configured to supply bed material to the first and second heat exchanger tubes (810, 820), respectively. The first heat exchanger tube (810) is arranged on a first side of a plane (P) intersecting the first feed chamber (310), and the second heat exchanger tube (820) is arranged on a second side of the plane (P). The first feed chamber (310) is configured to supply bed material to the second feed chamber (320).

Description

Technical Field

[0001] This invention relates to heat exchangers. This invention relates to particle coolers. This invention relates to loop-sealed heat exchangers. This invention relates to circulating fluidized bed boilers. Background Technology

[0002] A fluidized bed heat exchanger is known from US 5,184,671. A fluidized bed heat exchanger can be configured to connect to a steam generator to recover heat from the bed material of the fluidized bed. Typically, in such a heat exchanger, steam is fed into the heat exchanger and becomes superheated; therefore, such a fluidized bed heat exchanger can be referred to as a fluidized bed superheater. In a circulating fluidized bed boiler, the fluidized bed heat exchanger can be arranged in a loop seal. In this case, the heat exchanger can be referred to as a loop seal heat exchanger or a loop seal superheater.

[0003] Fluidized bed heat exchangers known from US 5,184,671 include heat exchange chambers (B, B) equipped with heat exchanger tubes. Figure 1 ), and a bypass chamber (C, parallel to it, without heat exchange tubes. Figure 1 In this design, the bypass chamber is the same size as the heat exchange chamber. Since the heat exchanger consists of only one chamber with heat exchanger tubes, controlling heat exchange simply by controlling the fluidizing air velocity in these two chambers (B and C) to a sufficient degree is problematic. Precise control is required to generate superheated steam, and to optimize the temperature and pressure of the superheated steam for use in the subsequent steam turbine. Typically, the steam turbine is sensitive to steam temperature and pressure.

[0004] For example, a loop-sealed superheater with two independent heat exchange chambers is known from WO2018 / 083367. The disclosed text... Figure 2 Part of section a is contained in this instruction manual. Figure 7 Reproduction in the middle. Setting up two independently controllable heat exchange chambers allows for better control of heat exchange from the bed material to the steam. These two heat exchange chambers are in... Figure 7 The figures are reproduced in the diagram and indicated by reference numerals 410 and 420. For example... Figure 7 As shown, in the prior art, two separate feeding chambers 310 and 320 are arranged side by side. Furthermore, each of the feeding chambers 310 and 320 supplies bed material 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 using only small particle separators, such as cyclones. Furthermore, there is a growing demand for decentralized boiler units with smaller sizes and capacities. This also indicates a trend towards smaller particle separators. As the size of the particle separator decreases, the available space in the heat exchanger typically decreases. Moreover, heat exchangers are often manufactured to allow their manufacturers (i.e., personnel) to enter one or more chambers to provide, for example, protective refractory material on at least some portions of the heat exchanger walls. Therefore, the individual chambers of the heat exchanger should be large enough for manufacturing (i.e., for personnel to enter). However, the overall size of the heat exchanger should be small enough. Furthermore, the heat exchange from the bed material to the circulating steam should be precisely controllable. Summary of the Invention

[0006] The objective of this invention is to provide a heat exchanger suitable for use as a loop-sealed heat exchanger in a circulating fluidized bed. Furthermore, even though the overall size (at least in one direction) is quite small, the chamber of the heat exchanger is sufficiently large for entry. Finally, the heat exchange from the bed material flowing between the heat exchange tubes to the circulating steam flowing inside the tubes is precisely controllable.

[0007] To recover heat and control heat exchange, the heat exchanger includes a first heat exchanger tube and a second heat exchanger tube, such that the bed material is configured to flow through a first feed chamber to the first heat exchanger tube and through a second feed chamber to the second heat exchanger tube. Furthermore, to ensure that both feed chambers are sufficiently large, the first feed chamber is configured to supply bed material to the second feed chamber. For example... Figure 7 Compared to other solutions, this saves space. Figure 7 In the proposed scheme, two separate feed chambers 310 and 320 are arranged side by side, and the bed material is supplied to only one of the heat exchange chambers.

[0008] According to an embodiment of the present invention, a heat exchanger suitable for recovering heat from bed material in a fluidized bed boiler is disclosed. The heat exchanger includes: a first heat exchanger tube; a second heat exchanger tube; a first feed chamber configured to supply bed material to the first heat exchanger tube; and a second feed chamber configured to supply bed material to the second heat exchanger tube, wherein the first heat exchanger tube is arranged only on a first side of a plane (P), and the second heat exchanger tube is arranged only on a second side of the plane (P); wherein the first feed chamber is configured to supply bed material to the second feed chamber.

[0009] Preferred embodiments of the invention are also disclosed in the accompanying drawings and following description. This specification explains the function of the heat exchangers in the preferred and other embodiments. Attached Figure Description

[0010] Figure 1 A side view of a circulating fluidized bed boiler is shown.

[0011] Figure 2 A top view of the different chambers of the heat exchanger is shown.

[0012] Figure 3 It shows Figure 2 Sectional view III-III of the heat exchanger in the middle. Figure 2 Section III-III is shown in the middle.

[0013] Figure 4a It shows Figure 2 Sectional view of heat exchanger IVa-IVa in the middle. Figure 2 The text indicates the cross-section IVa-IVa.

[0014] Figure 4b It shows Figure 2 Sectional view of the heat exchanger in section IVb-IVb. Figure 2 The section IVb-IVb is represented in the image.

[0015] Figure 5 It shows Figure 2 VV sectional view of the heat exchanger in the middle. Figure 2 The figure shows the cross-section VV. Figures 6a to 6d An embodiment of a nozzle for conveying fluidizing gas is shown, and

[0016] Figure 7 A solution based on existing technology is shown.

[0017] To illustrate the different views of the embodiment, three orthogonal directions Sx, Sy, and Sz are shown in the figures. Direction Sz is substantially vertical and upward when the heat exchanger is in use. Thus, direction Sz is substantially opposite to gravity. Detailed Implementation

[0018] Figure 1 A side view of a circulating fluidized bed boiler 1 is shown. The circulating fluidized bed boiler 1 includes a furnace 50, a particle separator 40 (e.g., a cyclone separator 41), and a loop sealing device 5. Figure 1 In the diagram, the flue gas passage is indicated by reference numeral 20. Typically, the boiler 1 includes heat exchangers 26 and 28 within the flue gas passage 20, which are configured to recover heat from the flue gas. Some heat exchangers may be superheaters 26, configured to superheat steam by recovering heat from the flue gas. Some heat exchangers may be economizers 28, configured to heat and / or boil water by recovering heat from the flue gas.

[0019] Within the furnace 50, some combustible material is configured to be burned. Some inert particulate material (e.g., sand) is also arranged within the furnace 50. The mixture of particulate material and combustible material and / or ash is referred to as the bed material. A grate 52 is arranged at the bottom of the furnace 50. The grate 52 is configured to supply air into the furnace to fluidize the bed material and burn at least some of the combustible material to generate heat, flue gas, and ash. In a circulating fluidized bed, the air supply is so strong that the bed material is configured to flow upward within the furnace 50. The grate 52 includes grate nozzles 54 for supplying air. The grate 52 defines a bottom ash passage 56 for removing ash from the furnace 50.

[0020] The bed material is conveyed from the top of the furnace 50 through the flue gas passage 20 to the particle separator 40 for separation from the gas. The separated bed material falls from the particle separator 40 (e.g., cyclone separator 41) through passage 60 into the loop seal device 5. A bed material layer (a single bed material layer) is formed in the loop seal device 5. This layer prevents combustion air or fluidizing air from flowing in the opposite direction from the furnace 50 to the cyclone separator 40. At least when the loop seal device 5 does not share a wall with the furnace 50, the bed material is returned to the furnace 50 via a conduit 15 configured to convey the bed material from the loop seal device 5 to the furnace 50. If the loop seal device 5 shares a wall with the furnace 50, the bed material is returned directly from the loop seal device 5 to the furnace 50.

[0021] refer to Figure 1 Heat exchanger 10 is arranged within the loop sealing device 5. Therefore, heat exchanger 10 can also be referred to as a loop sealing device heat exchanger, as it is suitable for use in a loop sealing device. Furthermore, unlike heat exchangers 26 and 28, heat exchanger 10 is configured to recover heat from the particulate material (i.e., bed material) circulating within the loop sealing device 5. Passage 60 is connected to inlet 31 of heat exchanger 10. Inlet 31 allows the bed material to enter heat exchanger 10. Therefore, heat exchanger 10 is suitable for recovering heat from the particulate bed material of the fluidized bed boiler 1.

[0022] refer to Figures 2 to 5 The heat exchanger 10 includes 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). These chambers have floors (including 102, 202, 312, and 322) and ceilings (not shown in the figures).

[0023] In this document, the term "chamber" refers to a space within heat exchanger 10 that is separated from another chamber by a wall (i.e., a vertical wall in use). As described below, the wall separating a chamber from an adjacent chamber does not need to extend the entire length from the bottom plate to the top plate of the chamber.

[0024] refer to Figure 2 The heat exchanger 10 includes a first heat exchanger tube 810 and a second heat exchanger tube 820. The purpose of the heat exchanger tubes 810 and 820 is to recover heat from the hot bed material flowing inside the heat exchanger 10.

[0025] The heat exchanger 10 includes a first feed chamber 310 configured to supply bed material to a first heat exchanger tube 810. The heat exchanger 10 also includes a second feed chamber 320 configured to supply bed material to a second heat exchanger tube 820. The purpose of the feed chambers 310 and 320 is to control the amount of bed material flowing to the first heat exchanger tube 810 and, on the other hand, to control the amount of bed material flowing to the second heat exchanger tube 820. Furthermore, to control heat exchange, the first and second heat exchanger tubes 810 and 820 are not arranged in the same chamber of the heat exchanger 10. In other words, the first and second heat exchanger tubes 810 and 820 are arranged at different locations within the heat exchanger 10. More specifically, the first heat exchanger tube 810 is arranged only on a first side of plane P, and the second heat exchanger tube 820 is arranged only on an opposite second side of plane P. Preferably, the heat exchanger tubes 810 and 820 are arranged relative to plane P (which is configured vertically in use), i.e., only on opposite sides of plane P. Preferably, the first heat exchanger tube 810 is arranged only on the first side of plane P, which intersects with at least one of the first feed chamber 310 and the second feed chamber 320, and the second heat exchanger tube 820 is arranged only on the second side of plane P, i.e., configured vertically in use. More preferably, the first heat exchanger tube 810 is arranged only on the first side of plane P, which intersects with both the first feed chamber 310 and the second feed chamber 320, and the second heat exchanger tube 820 is arranged only on the second side of plane P.

[0026] exist Figure 2 In this configuration, at least a portion of the first feed chamber 310 is arranged between the first heat exchanger tube 810 and the second heat exchanger tube 820. However, tubes 810 and 820 do not need to completely fill heat exchanger chambers 410 and 420. In this case, although the first feed chamber 310 is arranged between heat exchanger chambers 410 and 420 respectively provided with heat exchanger tubes 810 and 820, even a portion of the first feed chamber 310 is not necessarily required to be arranged between the first and second heat exchanger tubes 810 and 820.

[0027] The first feed chamber 310 is configured to supply bed material to the second feed chamber 320. For example... Figure 2 As indicated by the middle arrow, the first feed chamber 310 includes an outlet 316 for discharging bed material from the first feed chamber 310 to the second feed chamber 320.

[0028] The effect is that the width W310 of the first feed chamber 310 in direction Sy (and the width of the optional second feed chamber 320) remains greater than when the feed chambers 310 and 320 are arranged adjacent to each other in direction Sy. Furthermore, since the purpose of the heat exchanger tubes 810 and 820 is to recover heat, they are preferably designed to be in at least one direction (in...) Figure 2 The heat exchanger 10 (denoted by Sx) is relatively long. Therefore, even if the size of the heat exchanger 10 should be reduced, the length of the heat exchange chambers 410 and 420 in one direction should be maintained as much as possible for effective heat recovery. Therefore, especially for such chambers excluding heat exchanger tubes, there is usually available space in the Sx direction. This saves space and allows for precise control of heat transfer.

[0029] Preferably, the supply of bed material to the heat exchanger tubes 810 and 820 can be controlled independently of each other. Therefore, in one embodiment, the first feed chamber 310 is configured to supply bed material only to the first heat exchanger tube 810 and the second feed chamber 320. Furthermore, in one embodiment, the second feed chamber 320 is configured to supply bed material only to the second heat exchanger tube 820.

[0030] Since the first feed chamber 310 is configured to supply bed material to the second feed chamber 320, in a preferred embodiment, the second feed chamber 320 is configured to receive bed material only from the first feed chamber 310. For example, in one embodiment, the inlet chamber 100 is configured to supply bed material to the first feed chamber 310, and the inlet chamber 100 is configured to supply bed material to the second feed chamber 320 only through the first feed chamber 310. As detailed below, the inlet chamber 100 may also be configured to supply bed material to the bypass chamber 200.

[0031] Figure 2 The hollow (white) arrows indicate the outlets of the bed material for different chambers (104, 314, 414, 434, 316, 324, 424, 444, 106, 204). Figure 2 In this context, the arrows without overlapping lines (i.e., those used for outlets 314, 324, 434, 444, and 204) relate to outlets located at the upper part of the chamber. Figure 2 In this context, the arrows with one or more overlapping lines (i.e., the arrows used for outlets 104, 106, 316, 414, and 424) relate to outlets in the lower part of the chamber. The outlets can be formed as holes in the wall. Alternatively, the outlets in the lower part of the chamber can be formed, for example, by a wall extending downwards from the top plate but not to the level of the bottom plate. Correspondingly, the outlets in the upper part of the chamber can be formed, for example, by a wall extending upwards from the bottom plate but not to the level of the top plate.

[0032] In use, a first portion of the bed material flows between the first heat exchanger tubes 810. A second portion of the bed material flows between the second heat exchanger tubes 820. A third portion of the bed material flows through the bypass chamber 200 and bypasses the first and second heat exchanger tubes 810 and 820.

[0033] refer to Figure 1 and Figure 2 The bed material enters the heat exchanger 10 through inlet 31, which is located within inlet chamber 100. The bed material (i.e., the first and second portions of the bed material) can enter the first feed chamber 310 from inlet chamber 100 through outlet 104 (see...). Figure 2 This was also... Figure 3 Arrow A12 is shown in the diagram. Alternatively, the bed material (i.e., the third part of the bed material) can enter the bypass chamber 200 from the inlet chamber 100 through the outlet 106 (see...). Figure 2 This was also... Figure 3 Arrow A3 is shown in the diagram. (See image.) Figure 2 As shown, the inlet chamber 100 is configured to supply bed material only to the bypass chamber 200 and the first feed chamber 310. Naturally, as described above, a second portion of the bed material flows through the first feed chamber 310 to the second feed chamber 320.

[0034] The first portion of the bed material flows from the first feed chamber 310 through the outlet 314 to the first heat exchange chamber 410 (see...) Figure 2 In the first heat exchange chamber 410, the bed material flows between 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 bed material flows through the outlet 414 to the first outlet chamber 430, then through the outlet 434 to the pipe 15, and finally back to the furnace 50. If the heat exchanger 10 has a wall shared with the furnace 50, the outlet 434 can lead directly to the furnace 50. Alternatively, the outlet 414 can lead directly to the furnace 50, thus omitting the first outlet chamber 430.

[0035] Regarding the circulation of the second portion of the bed material, the second portion of the bed material flows from the first feed chamber 310 through the outlet 316 to the second feed chamber 320 (see...). Figure 2 The second portion of the bed material flows from the second feed chamber 320 to the second heat exchange chamber 420 through outlet 324. In the second heat exchange chamber 420, the bed material flows between the second heat exchanger tube 820 and outlet 424, thereby heating the heat transfer medium (typically steam) flowing within the second heat exchanger tube 820. The bed material flows through outlet 424 to the second outlet chamber 440, then through outlet 444 to pipe 15, and finally back to furnace 50. If heat exchanger 10 has a wall shared with furnace 50, outlet 444 can lead directly to furnace 50. Alternatively, outlet 424 can lead directly to furnace 50, thus eliminating the need for the second outlet chamber 440.

[0036] As detailed above, heat is recovered from the first and second portions of the bed material via the first and second heat exchanger tubes 810 and 820, respectively. However, in some cases, heat recovery from the bed material is not required, or less heat exchange is needed. Therefore, the third portion of the bed material can bypass the first and second heat exchanger tubes 810 and 820. For the circulation of the third portion of the bed material, the bed material can be discharged from the bypass chamber 200 through the outlet 204 to the pipe 15. Alternatively, the outlet 204 can lead directly to the furnace 50.

[0037] One or more chambers of heat exchanger 10 may be provided with ash removal channels 19. The purpose of the ash removal channels is to remove bottom ash from heat exchanger 10. Another purpose of the ash removal channels is to discharge bed material from the heat exchanger for maintenance. If bottom ash is removed from heat exchanger 10 during operation, the hot bottom ash can be conveyed to ash cooler 600 (see [link to ash cooler]). Figure 5 ( ), to recover heat from ash.

[0038] Therefore, in one embodiment, the heat exchanger 10 is arranged in the loop sealing device 5 of the circulating fluidized bed boiler 1. (See reference...) Figure 1 According to one embodiment, the circulating fluidized bed boiler 1 includes a furnace 50; a particle separator 40 (e.g., a cyclone separator 41) configured to separate the bed material from the flue gas that can be received from the furnace 50; and a loop sealing device 5 configured to receive the separated bed material from the particle separator 40. In this embodiment, the loop sealing device 5 has a heat exchanger 10 as described above and below.

[0039] 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 bed material is configured to flow through the first feed chamber 310. It should be noted that another portion of the bed material may flow through a bypass chamber. The bed material may flow into only one of chambers 310 and 200 at a time. However, in typical applications, a portion of the bed material flows to the first feed chamber 310 while another portion flows to the bypass chamber 200. Furthermore, the first portion of the separated bed material is configured to flow from the first feed chamber 310 to the first heat exchanger tube 810. Furthermore, the second portion of the separated bed material is configured to flow from the first feed chamber 310 to the second feed chamber 320, and then through the second feed chamber 320 to the second heat exchanger tube 820. As detailed above, the first portion of the separated bed material is configured to flow from the first feed chamber 310 to the first heat exchanger tube 810 without flowing through the second feed chamber 320. As described above, the third portion of the separated bed material is configured to flow into the bypass chamber 200 and is configured to bypass the first and second heat exchanger tubes 810, 820.

[0040] To provide outlet 316 to heat exchanger 10 and guide bed material as described above, in one embodiment, heat exchanger 10 includes a first wall 510 defining a first feed chamber 310 and a second feed chamber 320. That is, the first wall 510 separates the upper portion of the first feed chamber 310 from the upper portion of the second feed chamber 320. Figure 2 , Figure 3 and Figure 4a The first wall 510 is shown. In use, the first wall 510 is vertical. (As shown...) Figure 3 and Figure 4a As shown, the first wall 510 includes a first lower edge 512. When using the heat exchanger, the first lower edge 512 is positioned at a vertical level higher than one or more base plates 312, 322 of the first feed chamber 310 and the second feed chamber 320. Figure 3 The base plate is shown. More specifically, if the base plates 312 and 322 are arranged at the same vertical height, the first lower edge 512 is arranged at a higher vertical height. However, if the base plates 312 and 322 are not arranged at the same vertical height, the first lower edge 512 is arranged at a higher vertical height than the higher of the two base plates. Thus, the first feed chamber 310 is configured to supply bed material to the second feed chamber 320 from between the first lower edge 512 of the first wall 510 and one or more of the base plates 312 and 322 in the first and second feed chambers 310 and 320. The first lower edge 512 does not need to be as wide as the feed chambers 310 and 320. Instead, the first lower edge may be the upper edge of a hole provided in the first wall 510.

[0041] Preferably, the base plates 312, 322 of the first feed chamber 310 and the second feed chamber 320 are arranged at the same vertical height. Furthermore, preferably, the first lower edge 512 of the first wall 510 is not located on the top of a portion of the first wall 510. That is, if the first lower edge 512 is the upper edge of a hole in the wall 510, then the hole extends to the height of the base plates 312, 322; or if they are not at the same height, then they extend to the height of the higher of the multiple base plates. The effect is that the bed material can easily flow from the first feed chamber 310 to the second feed chamber 320.

[0042] It is important to note that throughout the instruction manual, the term "vertical height" refers to position in the vertical direction, i.e., altitude. For example, a horizontal plane is positioned at vertical height. Therefore, vertical height defines the position of a horizontal plane.

[0043] In order to control the flow of bed material through each chamber and thus control the heat exchange between bed material and steam, heat exchanger 10 is provided with nozzles for fluidizing bed material.

[0044] refer to Figure 3 Preferably, the heat exchanger 10 includes primary first nozzles 911. In operation, the primary first nozzles 911 are positioned at a vertical height lower than the first lower edge 512 of the first wall 510. That is, in operation, the primary first nozzles 911 are positioned below, but not necessarily directly below, the first lower edge 512 of the first wall 510. Furthermore, the primary first nozzles 911 are positioned in the first feed chamber 310. Moreover, the primary first nozzles 911 are configured to fluidize the bed material in the first feed chamber 310. Similarly, the heat exchanger 10 includes primary second nozzles 921. In operation, the primary second nozzles 921 are positioned at a vertical height lower than the first lower edge 512 of the first wall 510. The primary second nozzles 921 are positioned in the second feed chamber 320. The primary second nozzles 921 are configured to fluidize the bed material in the second feed chamber 320. By using nozzles 911 and 921, the bed material will be fluidized so that it flows from chamber 310 to chamber 320, and also flows through chambers 310 and 320.

[0045] By controlling the airflow through these nozzles 911, 921, it is possible to control how the bed material flowing into the first feed chamber 310 is divided into a first part of the flow pipe 810 and a second part of the flow pipe 820.

[0046] Therefore, in an embodiment of the circulating fluidized bed boiler 1 including the heat exchanger 10, the amount of fluidizing air supplied through the first main nozzle 911 is configured to be controlled independently of the amount of fluidizing air supplied through the second main nozzle 921. The air can be controlled, for example, by controlling the nozzles (911, 921) and / or by controlling baffles that affect the airflow to the nozzles (911, 921). For example, the first baffle can control the airflow to nozzle 911, and the second baffle can control the airflow to nozzle 921. The control can be automated. The control unit can be configured to control the nozzles and / or baffles accordingly.

[0047] However, it has been noted that due to exports 316 (see...) Figure 2 or Figure 3 The outlet (not shown) is located below edge 512 between the first feed chamber 310 and the second feed chamber 320. A portion of the air from the first main nozzle 911 is easily directed into the second feed chamber 320, and similarly, a portion of the air from the second main nozzle 921 is easily directed into the first feed chamber 310. This makes precise control of the bed material flow quite cumbersome. However, the nozzles 911 and 921 are advantageously arranged below the first lower edge 512 to allow the bed material to be conveyed through the outlet 316.

[0048] To provide more precise control, embodiments of heat exchanger 10 include secondary firstnozzles 912 (see [link to documentation]). Figure 3 In use, the first auxiliary nozzle 912 is positioned at a vertical height higher than the first lower edge 512 of the first wall 510. In use, the first auxiliary nozzle 912 is positioned above, but not necessarily directly above, the first lower edge 512 of the first wall 510. The first auxiliary nozzle 912 is positioned within the first feed chamber 310. The first auxiliary nozzle 912 is configured to fluidize the bed material within the first feed chamber 310. Because the first auxiliary nozzle 912 is positioned at a vertical height higher than the first lower edge 512 of the first wall 510, only a small amount of fluidizing air (if any) from these nozzles 912 flows towards the second feed chamber 320.

[0049] Accordingly, in one embodiment, the heat exchanger 10 includes secondary secondnozzles 922. In use, the secondary secondnozzles 922 are arranged at a vertical height higher than the first lower edge 512 of the first wall 510. The secondary secondnozzles 922 are arranged in a second feed chamber 320. The secondary secondnozzles 922 are configured to fluidize the bed material in the second feed chamber 320. Because the secondary secondnozzles 922 are arranged at a vertical height higher than the first lower edge 512 of the first wall 510, only a small amount of fluidizing air (if any) from these nozzles flows into the first feed chamber 310.

[0050] By controlling the airflow through these nozzles 912, 922, it is possible to control how the bed material flowing into the first feed chamber 310 is divided into a first part of the flow pipe 810 and a second part of the flow pipe 820.

[0051] Therefore, in embodiments of the circulating fluidized bed 1 including the heat exchanger 10, the amount of fluidizing air supplied through the first auxiliary nozzle 912 is configured to be controlled independently of the amount of fluidizing air supplied through the second auxiliary nozzle 922. Preferably, simultaneously, the amount of fluidizing air supplied through the first main nozzle 911 is configured to be controlled independently of the amount of fluidizing air supplied through the second main nozzle 921. Controlling the airflow through the nozzles by using nozzles and / or (one and / or more) baffles and / or controllers has been described.

[0052] It has been found that when the bed material flow is controlled to result in low airflow through the first auxiliary nozzle 912 and / or the second auxiliary nozzle 922, there is a tendency for bed material to enter these nozzles 912, 922. To prevent bed material from entering the nozzles and potentially clogging them, the nozzles can be closed from the top. Therefore, in one embodiment, the first auxiliary nozzle 912 is closed from the top to prevent bed material from entering the first auxiliary nozzle 912, and the second auxiliary nozzle 922 is closed from the top to prevent bed material from entering the second auxiliary nozzle 922.

[0053] Figure 3 A curved cover or roof is shown for nozzles 912 and 922 to prevent bed material from flowing into nozzles 912 and 922. Figure 6a This structure is shown in more detail. The curved cap or top cover 951 is indicated by its own reference numerals. The dashed lines indicate airflow. Furthermore, the nozzle can also be closed from the top. For example, in… Figure 6b In one embodiment, the nozzle has a curved shape, forming a downward-opening U-shape. Therefore, the curved portion 952 of the tube closes the nozzle from above (i.e., from the top). Furthermore, as... Figure 6c As shown, the flat cover or top cover 953 is sufficient to prevent bed material from entering the nozzle. Furthermore, many parts of the cover or top cover 951 can be substantially vertical, such as... Figure 6d As shown.

[0054] If necessary, the first main nozzle 911 can also be closed from the top to prevent bed material from entering the first main nozzle 911. If necessary, the second main nozzle 921 can also be closed from the top to prevent bed material from entering the second main nozzle 921.

[0055] As described above, in one embodiment, the second feed chamber 320 includes an outlet 324 for supplying bed material to the second heat exchange chamber 420 (see above). Figure 2 and Figure 3 Preferably, in this configuration, during use, the outlet 324 of the second feed chamber 320 is positioned at a vertical height higher than the first lower edge 512. (See reference) Figure 4a More specifically, preferably, the entire outlet 324 is arranged at a vertical height higher than the first lower edge 512. The outlet 324 may be defined by the upper edge of a wall that separates the lower part of the second feed chamber 320 from the second heat exchange chamber 420. Figure 4a and Figure 3 The curved arrow A2 in the diagram indicates the flow of bed material through outlet 324 above the wall. Arranging outlet 324 above the first lower edge 512 has the following technical effect: the second feed chamber 320 acts as a gas lock as part of it to prevent bed material from flowing in the wrong, opposite direction (i.e., not from chamber 420 through chamber 320 to chamber 310).

[0056] Preferably, the outlet 324 of the second feed chamber 320 is also arranged at a vertical height higher than the second auxiliary nozzle 922. This allows the second auxiliary nozzle 922 to be used more reliably to control the bed material flow. Therefore, the bed material will not escape from the second feed chamber through the outlet 324 before being fluidized by the air from the second auxiliary nozzle 922.

[0057] refer to Figure 3 and Figure 4b In one embodiment, the heat exchanger 10 includes a second wall 520 defining an inlet chamber 100 and a first feed chamber 310. In use, the second wall 520 is vertical. The second wall 520 includes a second lower edge 522 disposed at a vertical height higher than one or more base plates 312, 102 of the inlet chamber 100 and the first feed chamber 310. More specifically, if the base plates 312, 102 are disposed at the same vertical height, the second lower edge 522 is disposed at a vertical height higher than the base plates 312, 102. However, if the base plates 312, 102 are not disposed at the same vertical height, the second lower edge 522 is disposed at a vertical height higher than the higher of the two base plates. In this way, the inlet chamber 100 is configured to supply bed material to the first feed chamber 310 from between the second lower edge 522 of the second wall 520 and one or more bottom plates 102, 312 in the inlet chamber 100 and the first feed chamber 310. The second lower edge 522 does not need to be as wide as the first feed chamber 310 or the inlet chamber 100. Instead, the second lower edge 522 may be the upper edge of a hole arranged in the second wall 520.

[0058] Preferably, the bottom plates 312 and 102 of the first feed chamber 310 and the inlet chamber 100 are arranged at the same vertical height. Furthermore, preferably, the second lower edge 522 of the second wall 520 is not located on the top of a portion of the second wall 520. That is, if the second lower edge 522 is the upper edge of the hole, the hole extends to the height of the bottom plate (or the higher of the multiple bottom plates). The effect is that the bed material can easily flow from the inlet chamber 100 to the first feed chamber 310.

[0059] If the heat exchanger includes a second wall 520 and a first auxiliary nozzle 912, preferably, the first auxiliary nozzle 912 is arranged at a vertical height higher than the second lower edge 522 of the second wall 520. The effect is that air blown by the first auxiliary nozzle 912 is less likely to flow through the inlet 31 to the inlet chamber 100 and / or the passage 60 (see...). Figure 3 and Figure 1 ).

[0060] Preferably, when the heat exchanger includes a first wall 510 and a second wall 520, these walls are parallel. Furthermore, preferably, during operation, the first lower edge 512 is not positioned at a vertical height lower than the second lower edge 522. This ensures the proper functioning of the first feed chamber 310 because there is a tendency for the bed material to flow from the first feed chamber 310 to the second feed chamber 320 rather than from the first feed chamber 310 back to the inlet chamber 100. Figure 3 In this case, these edges 512 and 522 are arranged at approximately the same vertical height.

[0061] In one embodiment, a first feed chamber 310 is arranged between an inlet chamber 100 and a second feed chamber 320. (See reference...) Figure 2 As detailed above, in order to effectively recover heat, the length of the heat exchange chambers 410, 420 in at least one direction should be kept as long as possible. Therefore, space is typically available for these chambers 100, 310, 320, particularly in that direction. For clarity, in a preferred embodiment, the inlet chamber 100, the first feed chamber 310, and the second feed chamber 320 are arranged adjacent to the first heat exchange chamber 410, which is provided with the first heat exchanger tube 810. Here, the term "adjacent" means that only one vertical wall is arranged between two adjacent chambers. Preferably, the inlet chamber 100, the first feed chamber 310, and the second feed chamber 320 are arranged adjacent to the second heat exchange chamber 420, which is provided with the second heat exchanger tube 820.

[0062] In other words, in one embodiment, the heat exchanger 10 includes a third wall 530 defining a first heat exchange chamber 410 and a fourth wall 540 defining a second heat exchange chamber 420. Figure 2 , Figure 4a and Figure 4b These walls 530 and 540 are shown. In use, the third wall 530 and the fourth wall 540 are vertical. Furthermore, in... Figure 2 In one embodiment, the third wall 530 is parallel to the fourth wall 540. Furthermore, in... Figure 2 In this embodiment, at least a portion of the first wall 510 is disposed between the third wall 530 and the fourth wall 540. It should be noted that the first wall may extend longer vertically than walls 530 and 540. In one embodiment, the first wall 510 is perpendicular to the third wall 530. Furthermore, if a second wall 520 is present, preferably at least a portion of it is disposed 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 defines a first feed chamber 310. In one embodiment, a portion of the third wall 530 defines a second feed chamber 320. In one embodiment, a portion of the fourth wall 540 defines the first feed chamber 310. In one embodiment, a portion of the fourth wall 540 defines the second feed chamber 320.

[0063] More preferably, the inlet chamber 100 is further arranged between the first feed chamber 310 and the bypass chamber 200. In this case, the bypass chamber 200 can be arranged adjacent to the first heat exchange chamber 410. Alternatively, the bypass chamber 200 can be arranged adjacent to the second heat exchange chamber 420. Accordingly, in Figure 2 In one embodiment, a portion of the third wall 530 also defines the bypass chamber 200. Furthermore, a portion of the fourth wall 540 also defines the bypass chamber 200.

[0064] 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 includes a third nozzle 930 disposed in the lower portion of the inlet chamber 100 and configured to fluidize the bed material in the inlet chamber 100. (Reference) Figure 3 .

[0065] Preferably, the width W310 of the first feed chamber 310 is at least 500 mm, which allows an operator to enter the first feed chamber 310, for example, during its manufacturing. Here, the width W310 is defined 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. In the case where the heat exchanger includes a third wall 530 and a fourth wall 540, and a portion of the walls 530, 540 defines the first feed chamber 310, the width W310 remains between the third wall 530 and the fourth wall 540.

[0066] There is no technical reason for the upper limit of the width W310 to differ from the size of the heat exchanger 10 used for the upper limit. However, if the width W310 is so large that the first feed chamber 310 can be divided into two adjacent sections accessible to two people in the direction of the width W310, there is no technical reason to guide the bed material through the first feed chamber 310 to the second feed chamber 320. Instead, the first feed chamber 310 and the second feed chamber 320 can be arranged side by side, and the bed material can be arranged to flow directly from the inlet chamber 100 into each feed chamber, as... Figure 7 As shown. Furthermore, the width and length of the entrance chamber 100 are generally equal to the width and length of the passageway 60 at entrance 31 (see...). Figure 2 3). Furthermore, for manufacturing reasons, the width W310 is preferably equal to the width of the entrance chamber 100. For these reasons, the width W310 can be between, for example, 500 mm and 1600 mm.

[0067] For similar reasons, the width W10 of the entire heat exchanger 10, defined 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, between 4000 mm and 7700 mm.

[0068] As described above, the bed material can enter the first heat exchange chamber 410 from the first feed chamber 310 through the outlet 314 (see...). Figure 2 Preferably, in use, the outlet 314 of the first feed chamber 310 is arranged at a vertical height higher than the second lower edge 522 of the second wall 520 (see...). Figure 4b More specifically, preferably, the entire outlet 314 is arranged at a vertical height higher than the second lower edge 522. The outlet 314 may be defined by the upper edge of the wall separating the lower part of the first feed chamber 310 from the first heat exchange chamber 410. Figure 4b and Figure 3 The curved arrow A1 in the diagram indicates the flow of bed material through outlet 314 above the wall. Arranging outlet 314 above the second lower edge 522 has the following technical effect: the first feed chamber 310 acts as an airlock, preventing bed material from flowing in the wrong, opposite direction (i.e., not from chamber 410 through chamber 310 to chamber 100).

[0069] Alternatively, preferably, in use, the outlet 314 of the first feed chamber 310 is arranged at a vertical height higher than the first lower edge 512 of the first wall 510 (see [reference]). Figure 3 More specifically, preferably, the entire outlet 314 is positioned at a vertical height higher than the first lower edge 512. Positioning the outlet 314 above the first lower edge 512 provides the technical advantage of better control over material flow.

[0070] Preferably, in use, the outlet 314 of the first feed chamber 310 is positioned at a vertical height higher than the first auxiliary nozzle 912 (see [reference]). Figure 3 The effect is that the first nozzle 912 can fluidize the bed material in the first feed chamber 310 before it escapes into the first heat exchange chamber 410. In this way, the control of the material flow is improved.

[0071] refer to Figure 2 and Figure 3 In one embodiment, the heat exchanger 10 includes a fifth wall 550 defining a bypass chamber 200 and an inlet chamber 100. In this way, the fifth wall 550 separates at least the upper portion of the bypass chamber 200 from the inlet chamber 100. As detailed above, the inlet chamber 100 includes an inlet 31 for bed material. The fifth wall 550 includes a fifth lower edge 552 (see [link to previous embodiment]). Figure 3In use, the fifth lower edge 552 is positioned at a vertical height higher than one or more bottom plates 202, 102 in the entrance chamber 100 and the bypass chamber 200. Thus, the entrance chamber 100 is configured to supply bed material to the bypass chamber 200.

[0072] More precisely, if the base plates 102 and 202 are arranged at the same vertical height, then the fifth lower edge 552 is arranged at a higher vertical height. However, if the base plates 102 and 202 are not arranged at the same vertical height, then the fifth lower edge 552 is arranged at a higher vertical height than the higher of the two base plates. Thus, the entrance chamber 100 is configured to supply bed material to the bypass chamber 200 from between the fifth lower edge 552 of the fifth wall 550 and one or more of the base plates 102 and 202 in the entrance chamber 100 and the bypass chamber 200. The fifth lower edge 552 does not need to be as wide as the entrance chamber 100 or the bypass chamber 200. Instead, the fifth lower edge 552 can be the upper edge of a hole arranged in the fifth wall 550.

[0073] Preferably, the base plates 102 and 202 of the inlet chamber 100 and the bypass chamber 200 are arranged at the same vertical height. Furthermore, preferably, the fifth lower edge 552 of the fifth wall 550 is not located on the top of a portion of the fifth wall 550. That is, if the fifth lower edge 552 is the upper edge of the hole, the hole extends to the height of the higher of one or more base plates. The effect is that the bed material can easily flow from the inlet chamber 100 to the bypass chamber 200.

[0074] The bypass chamber 200 is adapted to bypass the first and second heat exchanger tubes 810, 820 of the heat exchanger 10. This allows control over the amount of bed material from which heat is recovered. To control the bed material flow through the bypass chamber 200, the heat exchanger 10 includes a fourth nozzle 940 disposed at the lower portion of the bypass chamber 200 (see [link to relevant documentation]). Figure 3 The fourth nozzle 940 is configured to fluidize the bed material in the bypass chamber 200.

[0075] Even if the nozzles 911 and 912 in the first feed chamber 310 affect the material flow to the first heat exchanger tube 810, preferably, the bed material flow in the first heat exchanger chamber 410 is also enhanced by a fluidizing gas. Therefore, in one embodiment, the heat exchanger includes a fifth nozzle 950 disposed in the lower part of the first heat exchanger chamber 410. The fifth nozzle 950 is configured to fluidize the bed material in the first heat exchanger chamber 410, as shown in the reference... Figure 4a , Figure 4b and Figure 5 .

[0076] Even if the nozzles 921 and 922 in the second feed chamber 320 affect the material flow to the second heat exchanger tube 820, preferably, the bed material flow in the second heat exchanger chamber 420 is also enhanced by a fluidizing gas. Therefore, in one embodiment, the heat exchanger includes a sixth nozzle 960 disposed in the lower part of the second heat exchanger chamber 420. The sixth nozzle 960 is configured to fluidize the bed material in the second heat exchanger chamber 420, as referenced. Figure 4a and Figure 4b .

[0077] For similar reasons, in one embodiment, the heat exchanger includes a seventh nozzle 970 configured to fluidize the bed material in the first outlet chamber 430 (see [link to document]). Figure 5 For similar reasons, in one embodiment, the heat exchanger includes an eighth nozzle (not shown) configured to fluidize the bed material in the second outlet chamber 440.

Claims

1. A heat exchanger (10) suitable for recovering heat from the bed material of a fluidized bed boiler (1), said heat exchanger (10) comprising: - First heat exchanger tube (810). - Second heat exchanger tube (820). - The first feed chamber (310) is configured to supply bed material to the first heat exchanger tubes (810), and - The second feed chamber (320) is configured to supply bed material to the second heat exchanger tubes (820), wherein - The first heat exchanger tube (810) is arranged only on a first side of a plane (P), and the second heat exchanger tube (820) is arranged only on a second side of the plane (P). Its features are, - Wall (520), defining the entrance chamber (100) and the first feed chamber (310), and - An inlet (31) for receiving bed material, said inlet (31) being arranged in the inlet chamber (100), - The first feed chamber (310) is arranged between the inlet chamber (100) and the second feed chamber (320), and - The first feed chamber (310) is configured to supply bed material to the second feed chamber (320).

2. The heat exchanger (10) according to claim 1, wherein - The first feed chamber (310) is configured to supply bed material only to the first heat exchanger tube (810) and the second feed chamber (320), and - The second feed chamber (320) is configured to supply bed material only to the second heat exchanger tube (820).

3. The heat exchanger (10) according to claim 1 or 2, comprising: - A first wall (510) defines the first feed chamber (310) and the second feed chamber (320), the first wall (510) comprising: - The first lower edge (512) is arranged at a vertical height higher than one or more of the base plates (312, 322) in the first feed chamber (310) and the second feed chamber (320) during use, thereby - The first feed chamber (310) is configured to supply bed material to the second feed chamber (320) from the first lower edge (512) of the first wall (510) and one or more bottom plates (312, 322) of the first feed chamber (310) and the second feed chamber (320).

4. The heat exchanger (10) according to claim 3, comprising: - A first main nozzle (911), in use, is positioned at a vertical height lower than the first lower edge (512) of the first wall (510) and located within the first feed chamber (310), and is configured to fluidize the bed material in the first feed chamber (310); and - The second main nozzle (921) is arranged at a vertical height lower than the first lower edge (512) of the first wall (510) and located in the second feed chamber (320), and is configured to fluidize the bed material in the second feed chamber (320).

5. The heat exchanger (10) according to claim 3, comprising: - The first auxiliary nozzle (912) is arranged at a vertical height higher than the first lower edge (512) of the first wall (510) and located in the first feed chamber (310), and is configured to fluidize the bed material in the first feed chamber (310); as well as - The second auxiliary nozzle (922) is arranged at a vertical height higher than the first lower edge (512) of the first wall (510) and located in the second feed chamber (320), and is configured to fluidize the bed material in the second feed chamber (320).

6. The heat exchanger (10) according to claim 3, wherein - The second heat exchanger tube (820) is arranged in the second heat exchange chamber (420) of the heat exchanger (10), and - The second feed chamber (320) includes an outlet (324) for supplying bed material to the second heat exchange chamber (420), wherein - In use, the outlet (324) of the second feed chamber (320) is arranged at a vertical height higher than the first lower edge (512).

7. The heat exchanger (10) according to claim 1 or 2, wherein, The wall (520) includes: - The second lower edge (522) is positioned at a vertical height higher than one or more bottom plates (312, 102) in the inlet chamber (100) and the first feed chamber (310), thereby - The entrance chamber (100) is configured to supply bed material to the first feed chamber (310) from the second lower edge (522) of the wall (520) between the entrance chamber (100) and one or more bottom plates (312, 102) of the first feed chamber (310).

8. The heat exchanger (10) according to claim 7, further comprising the first wall (510) according to claim 3, wherein - The wall (520) is parallel to the first wall (510), and - The first lower edge (512) is not arranged at a vertical height lower than the second lower edge (522).

9. The heat exchanger (10) according to claim 7, wherein - The inlet chamber (100), the first feed chamber (310) and the second feed chamber (320) are arranged adjacent to the first heat exchange chamber (410) provided with the first heat exchanger tube (810).

10. The heat exchanger (10) according to claim 7, wherein - The first heat exchanger tube (810) is arranged in the first heat exchange chamber (410) of the heat exchanger (10), and - The first feed chamber (310) includes an outlet (314) for supplying bed material to the first heat exchange chamber (410) of the heat exchanger (10), and - In use, the outlet (314) of the first feed chamber (310) is arranged at a vertical height higher than the first lower edge (512), and / or - In use, the outlet (314) of the first feed chamber (310) is arranged at a vertical height higher than the second lower edge (522).

11. The heat exchanger (10) according to claim 3, comprising: - The third wall (530) defines the first heat exchange chamber (410) on which the first heat exchanger tube (810) is disposed, and - The fourth wall (540) defines a second heat exchange chamber (420) on which the second heat exchanger tube (820) is provided, wherein - The third wall (530) is parallel to the fourth wall (540), and - At least a portion of the first wall (510) is disposed between the third wall (530) and the fourth wall (540).

12. The heat exchanger (10) according to claim 1 or 2, comprising: - A fifth wall (550) defining a bypass room (200) and an entrance room (100), said fifth wall (550) comprising: - The fifth lower edge (552), in use, is positioned at a vertical height higher than one or more of the base plates (202, 102) in the entrance chamber (100) and the bypass chamber (200), thereby - The entrance chamber (100) is configured to supply bed material to the bypass chamber (200), wherein - The bypass chamber (200) is adapted to bypass the heat exchanger tubes (810, 820) of the heat exchanger (10).

13. A circulating fluidized bed boiler (1), comprising: - Furnace (50); - A particle separator (40) is configured to separate the bed material from the flue gas that can be received from the furnace (50), and - A loop sealing device (5) is configured to receive separated bed material from the particle separator (40), the loop sealing device (5) comprising a heat exchanger (10) as described in claim 1 or 2, wherein the heat exchanger (10) is arranged such that: - At least a portion of the separated bed material is configured to pass through the first feed chamber (310). - The first portion of the separated bed material is configured to flow from the first feed chamber (310) to the first heat exchanger tube (810), and - The second portion of the separated bed material is configured to flow from the first feed chamber (310) to the second feed chamber (320), and then through the second feed chamber (320) to the second heat exchanger tube (820).

14. A circulating fluidized bed boiler (1), comprising: - Furnace (50) - A particle separator (40) is configured to separate the bed material from the flue gas that can be received from the furnace (50), and - A loop sealing device (5) is configured to receive separated bed material from the particle separator (40), the loop sealing device (5) comprising a heat exchanger (10) according to any one of claims 4 to 6, wherein the heat exchanger (10) is arranged such that: - At least a portion of the separated bed material is configured to pass through the first feed chamber (310). - The first portion of the separated bed material is configured to flow from the first feed chamber (310) to the first heat exchanger tube (810), and - The second portion of the separated bed material is configured to flow from the first feed chamber (310) to the second feed chamber (320), and then through the second feed chamber (320) to the second heat exchanger tube (810); and - The amount of fluidizing air supplied through the first main nozzle (911) is configured to be controlled independently of the amount of fluidizing air supplied through the second main nozzle (921).

15. A circulating fluidized bed boiler (1), comprising: - Furnace (50) - A particle separator (40) is configured to separate the bed material from the flue gas that can be received from the furnace (50), and - A loop sealing device (5) is configured to receive separated bed material from a particle separator (40), the loop sealing device comprising a heat exchanger (10) as described in claim 5 or 6, wherein the heat exchanger (10) is arranged such that: - At least a portion of the separated bed material is configured to pass through the first feed chamber (310). - The first portion of the separated bed material is configured to flow from the first feed chamber (310) to the first heat exchanger tube (810), and - The second portion of the separated bed material is configured to flow from the first feed chamber (310) to the second feed chamber (320), and then through the second feed chamber (320) to the second heat exchanger tube (810); and - The amount of fluidizing air supplied through the first auxiliary nozzle (912) is configured to be controlled independently of the amount of fluidizing air supplied through the second auxiliary nozzle (922).

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