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JP-7856292-B2 - Heat exchanger for loop seal of circulating fluidized bed boiler and circulating fluidized bed boiler

JP7856292B2JP 7856292 B2JP7856292 B2JP 7856292B2JP-7856292-B2

Inventors

  • ペッカ レフトネン

Assignees

  • バルメット テクノロジーズ オサケユキチュア

Dates

Publication Date
20260511
Application Date
20220406
Priority Date
20210407

Claims (14)

  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 perpendicular 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 and 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, - An inlet chamber and a second wall restricting the first supply chamber, and - an inlet for receiving a fluid medium, the inlet having an inlet located within the inlet chamber, and 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 and 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, the fifth wall being - 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.

Description

This invention relates to heat exchangers. This invention relates to particle coolers. This invention relates to loop-seal heat exchangers. This invention relates to circulating fluidized bed boilers. Fluidized bed heat exchangers are known from Patent Document 1. Fluidized bed heat exchangers are sometimes connected to a steam generator to recover heat from the fluidized medium (bed material) of the fluidized bed. Typically, in such a heat exchanger, steam is supplied to the heat exchanger and superheated; therefore, such a fluidized bed heat exchanger is sometimes called a fluidized bed superheater. In circulating fluidized bed boilers, the fluidized bed heat exchanger may be located in a loop seal. In such cases, the heat exchanger may be called a loop seal heat exchanger or loop seal superheater. The fluidized bed heat exchanger known from Patent Document 1 has a heat exchange chamber (Figure 1, B) equipped with heat transfer tubes and a bypass chamber (Figure 1, C) parallel to it that does not have heat exchanger tubes. In this solution, the bypass chamber is the same size as the heat exchange chamber. Since the heat exchanger consists of only one chamber equipped with heat exchanger tubes, it is problematic to adequately control heat exchange by controlling only the fluid air velocity of these two chambers (B and C). Precise control is required to generate superheated steam with optimized temperature and pressure for the next steam turbine. Steam turbines are typically sensitive to the temperature and pressure of the steam. A loop-seal superheater with two separate heat exchange chambers is known, for example, from Patent Document 2. Several portions of Figure 2a of Patent Document 2 are 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. 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. Furthermore, there is 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, typically less space is available for the heat exchanger. Additionally, 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. U.S. Patent No. 5,184,671International Publication No. 2018/083367 As needed, an object of the present invention is to provide a heat exchanger suitable for use as a loop-seal heat exchanger in a circulating fluidized bed. Furthermore, even if the overall size is moderately small (at least in one direction), the heat exchanger chamber is adequately 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. 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, where two separate supply chambers 310, 320 are arranged side-by-side and supply the fluid medium to only one of the heat exchange chambers. 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. A circulating fluidized bed boiler is shown in a side view.The different chambers of the heat exchanger are shown in a top view.Figure 2 shows the cross-section III-III of the heat exchanger, and the cross-section III-III