WO2017182855A1 - Système de chaudière à lit fluidisé circulant - Google Patents

Système de chaudière à lit fluidisé circulant Download PDF

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Publication number
WO2017182855A1
WO2017182855A1 PCT/IB2016/053814 IB2016053814W WO2017182855A1 WO 2017182855 A1 WO2017182855 A1 WO 2017182855A1 IB 2016053814 W IB2016053814 W IB 2016053814W WO 2017182855 A1 WO2017182855 A1 WO 2017182855A1
Authority
WO
WIPO (PCT)
Prior art keywords
flue gas
flue gases
water wall
flue
cyclone separator
Prior art date
Application number
PCT/IB2016/053814
Other languages
English (en)
Inventor
Subramaniam Chiramadam RAMANATHAN
Radhe S JHA
Devkumar Fulchand GUPTA
Ramakrishna Ramanath SONDE
Original Assignee
Thermax Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thermax Limited filed Critical Thermax Limited
Publication of WO2017182855A1 publication Critical patent/WO2017182855A1/fr
Priority to PH12018502254A priority Critical patent/PH12018502254A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B31/00—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus
    • F22B31/0007—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus with combustion in a fluidized bed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/02—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed
    • F23C10/04—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
    • F23C10/08—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases
    • F23C10/10—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
    • F23M9/00—Baffles or deflectors for air or combustion products; Flame shields
    • F23M9/10—Baffles or deflectors formed as tubes, e.g. in water-tube boilers

Definitions

  • the present disclosure relates to the field of mechanical engineering and particularly relates to the field of circulating fluidized bed combustion boilers.
  • BACKGROUND in a circulating fluidized bed combustion boiler, fuel and inert material are circulating at a high velocity in a combustion chamber. The mixture of fuel and inert material is then passed to a cyclone. The cyclone receives the fuel and inert material and then supplies the fuel and inert material back to the combustion chamber using a loop seal device that is connected to the delivery end of a dip leg that connects the bottom of the cyclone and the loop seal. The same fuel enters the boiler several times, thereby providing sufficient residence time to the fuel for combustion. This improves the efficiency and reduces the emission of the boiler.
  • flue gases leaving the cyclone have a vortex motion with a very large tangential velocity. Stabilization of the flue gases takes significant time as a result of this high tangential velocity.
  • the circular motion of the flue gases causes non-uniform distribution thereof over the heat exchangers.
  • the circular motion of the flue gases causes reduction in the utilization of the heat transfer area of the heat exchanger as they cause a non-uniform distribution of the flue gas contact with the exchanging surfaces, thereby leading to poor heat transfer performance. Erosion of an inner portion of the heat exchangers may also occur due to impinging of the abrasive particles present in the flue gases at high velocity.
  • An object of the present disclosure is to provide a circulating fluidized bed combustion boiler system that partially obstructs the flow of flue gases coming out of the cyclone and minimizes/eliminates the vortex phenomenon in the flue gas flow.
  • Another object of the present disclosure is to provide a circulating fluidized bed combustion boiler system that streamlines the flow of flue gases coming out of the cyclone as they enter the vertical column.
  • Yet another object of the present disclosure is to provide a circulating fluidized bed combustion boiler system that increases the heat transfer performance at the heat exchangers positioned in the vertical column like the super-heater, the economizer and the air heater.
  • Still another object of the present disclosure is to provide a circulating fluidized bed combustion boiler system that improves the velocity profile of flue gases.
  • the present disclosure envisages a circulating fluidized bed boiler system.
  • the circulating fluidized bed boiler system comprises a combustion chamber for fluidizing and combusting fuel particles to generate flue gases.
  • the combustion chamber has a flue gas outlet.
  • the flue gas outlet is configured at an operative top end of the combustion chamber.
  • a cyclone separator is in fluid communication with the flue gas outlet.
  • the cyclone separator is configured to receive the flue gases and partly burnt fuel particles and is further configured to separate the partly burnt fuel from the flue gases.
  • a flue gas conduit is in fluid communication with the cyclone separator, and is configured to receive the flue gases from the cyclone separator and transport the flue gases to a heat exchange column.
  • a flue gas vortex breaker section is disposed within the flue gas conduit and includes a water wall membrane that is configured to streamline and resist the flow of the flue gases.
  • the water wall membrane includes a plurality of vertical tubes disposed therewithin and a plurality of fins is alternately disposed between the plurality of vertical tubes.
  • the water wall membrane is constituted by a near-end wall, a plurality of side walls and a far end wall that together define an interior space within the water wall membrane.
  • the far end wall is opposite to the near-end wall.
  • the near-end wall of the waterwall membrane is in fluid communication with a first outlet of the cyclone separator.
  • the walls of the water wall membrane comprises a plurality of vertical tubes and a plurality of fins placed between them. The plurality of fins is arranged alternately such that water wall membrane has a mesh like structure.
  • the plurality of vertical tubes includes at least one bent tube.
  • the plurality of vertical tubes has a cross-sectional shape selected from the group consisting of a circle, a rectangle, a square, a triangle, and any geometrical or non-geometrical shape thereof.
  • the heat exchange column includes at least one of a superheater, an economizer, an air pre- heater.
  • Figure 1 illustrates a schematic view of a conventional circulating fluidized bed combustion boiler system
  • Figure2 illustrates a schematic view of a circulating fluidized bed combustion boiler system in accordance with an embodiment of the present disclosure
  • Figure 3 illustrates an isometric view of a flue gas vortex breaker section of the circulating fluidized bed combustion boiler system of Figure 2;
  • Figure 4 illustrates a schematic view of a portion of the flue gas vortex breaker section of Figure 3.
  • FIG. 1 illustrates a schematic view of a conventional circulating fluidized bed combustion boiler system 100 (hereinafter referred to as conventional system 100).
  • the conventional system 100 comprises a combustion chamber 101, a cyclone 102 and a vertical column 103.
  • the combustion chamber 101 of the conventional system 100 comprises a bed of inert material (not shown in the figure) at an operative lower end of the combustion chamber 101. Coal is spread over the bed where the combustion of the coal takes place. Air is supplied to the combustion chamber 101 from under the bed at high pressure. The high pressure air lifts the coal and inert material, thereby keeping the coal and inert material in suspension. Further, the fine particles of partly burned coal, ash and inert material are carried along with the flue gases to an operative top end of the combustion chamber 101. The operative top end of the combustion chamber 101 is in fluid communication with the cyclone 102.
  • the coal particles separate from the flue gases and fall into a loop seal device placed at the bottom of the cyclone 102, thereby returning the coal particles back into the combustion chamber 101 for recirculation.
  • the same coal particles enter the boiler several times, thereby providing sufficient residence time to the coal for combustion. This improves the efficiency and reduces the emission of the conventional system 100.
  • the flue gases from the cyclone 102 is then passed to the vertical column 103.
  • the flue gases entering the vertical column 103 from the cyclone 102 has a vortex motion of a very large tangential velocity.
  • the high tangential velocity of the flue gases causes the flue gases to stabilize after a considerable amount of time.
  • the circular motion of the flue gases causes non-uniform distribution of the flue gases over the heat exchangers (not explicitly labelled in the figure), thereby leading to a poor heat transfer performance.
  • Figure 2 illustrates a schematic view of a circulating fluidized bed boiler system 200 in accordance with an embodiment of the present disclosure.
  • Figure 3 illustrates an isometric view of a flue gas vortex breaker section 209 of the circulating fluidized bed boiler system 200 of the Figure 2.
  • Figure 4 illustrates a schematic view of a portion of the flue gas vortex breaker section 209 of the Figure 3.
  • the present disclosure envisages a circulating fluidized bed boiler system 200.
  • the circulating fluidized bed boiler system 200 (hereinafter referred to as the "system 200") includes a combustion chamber 201, a cyclone separator 202, and the flue gas vortex breaker section 209.
  • the combustion chamber 201 has a flue gas outlet 201a at an operative top end.
  • the combustion chamber 201 is configured to fluidize and combust fuel particles to generate flue gases.
  • the flue gas outlet 201a is in fluid communication with an inlet 202i of the cyclone separator 202.
  • the cyclone separator 202 is configured to receive the fluidized and combusted fuel particles from the combustion chamber 201 and is further configured to separate partly burnt fuel from the flue gases.
  • a flue gas conduit 208 is in fluid communication with the cyclone separator 202, and is configured to receive the flue gases from the cyclone separator 202 and transport flue gases to a heat exchange column 203.
  • the flue gas vortex breaker section 209 is disposed within the flue gas conduit 208.
  • the flue gas vortex breaker section 209 includes a water wall membrane 204. The water wall membrane 204 is configured to streamline and resist the flow of the flue gases.
  • the combustion chamber 201 of the system 200 comprises a bed of inert material (not shown in the figure) disposed at an operative lower end of the combustion chamber 201.
  • Fuel is spread over the bed where the combustion of the fuel takes place.
  • the fuel is coal.
  • Air is supplied to the combustion chamber 201 from under the bed placed at the operative lower end of the combustion chamber 201 at high pressure. The high pressure air lifts the fuel and inert materials, thereby keeping the fuel and the inert material in suspension. Further, the fine particles of the partly burned fuel, ash and inert materials are carried along with the flue gases to the cyclone separator 202from the inlet 202i, via the flue gas outlet 201a of the combustion chamber 201.
  • the partly burned fuel separates from the flue gases and falls into a loop seal device (not shown in the figures) via the second outlet 202b placed at the bottom of the cyclone separator 202, thereby returning the partly burned fuel back into the combustion chamber 201 for recirculation.
  • the same fuel enters the combustion chamber 201 several times, thereby providing sufficient residence time to the fuel for combustion and improving the efficiency and reducing the emission of the system 200.
  • the heat exchange column 203 is in fluid communication with the cyclone separator 202 via the flue gas conduit 208.
  • the flue gases travelling towards the heat exchange column 203 from a first outlet 202a of the cyclone separator 202 travels via, the flue gas vortex breaker section 209 that is disposed within the flue gas conduit 208.
  • the water wall membrane 204 is placed within the flue gas vortex breaker section 209.
  • the water wall membrane 204 is defined by a near-end wall 212, a plurality of side walls 214 and a far end wall 213.
  • the far end wall 213 is opposite to the near-end wall 212.
  • the near- end wall 212, the plurality of sidewalls 214, and the far end wall 213 define an interior space within the water wall membrane 204.
  • the near-end wall 212 is positioned in the path of the flow of the flue gases from the first outlet 202a of the cyclone separator 202 to the far end wall 213 of the water wall membrane 204, such that it is upstream of the far end wall 213 with respect to the flow of the flue gases.
  • a first end 210 of the water wall is defined by the near-end wall 212 of the water wall membrane 204 and is in fluid communication with the first outlet 202a of the cyclone separator 202, via the flue gas conduit 208.
  • the first end 210 of the water wall membrane 204 is the side comprising the at least one bent tube 205.
  • a second end 211 of the water wall membrane 204 is in fluid communication with the operative top end of the heat exchange column 203.
  • the second end 211 of the water wall membrane 204 comprises the portion of the plurality of vertical tubes 206 leading to the heat exchange column 203.
  • the water wall membrane 204 resembles a mesh like structure 215.
  • the water wall membrane 204 includes a plurality of vertical tubes 206 disposed therewithin and a plurality of fins 207 that is alternately disposed between the plurality of vertical tubes 206.
  • the plurality of vertical tubes 206 includes at least one bent tube 205.
  • the plurality of vertical tubes 206 includes a bent section defined by at least one bent tube 205 placed in proximity of the near-end wall 212.
  • the plurality of vertical tubes 206 have a cross-sectional shape selected from the group consisting of a circle, a rectangle, a square, a triangle, and any geometrical or non- geometrical shape thereof.
  • the plurality of fins 207 of the water wall membrane 204 provides a resistance to the flow of the flue gases exiting the cyclone separator 202, thereby reducing the velocity vector and breaking the vortex of the flue gases.
  • the plurality of fins 207 also partially obstructs and streamline the flow of the flue gases.
  • the streamlined flue gases with reduced velocity vector enter the heat exchange column 203 and flow through a superheater 220, an economizer 221 and an air preheater 222 that are placed in the heat exchange column 203, thereby maximizing the heat transfer area for the effective heat transfer and significantly increasing the heat transfer performance of the system 200.
  • the flue gases from the heat exchange column 203 exits to the atmosphere.
  • the circulating fluidized bed boiler system 200 of the present disclosure therefore, provides substantially increased heat transfer performance of the heat exchangers in the vertical column and also reduces the risk of erosion of the heat exchangers as compared to the existing systems.
  • the present disclosure described herein above has several technical advantages including, but not limited to, the realization of a circulating fluidized bed boiler system that: partially obstructs the flow of flue gases for elimination of vortex in the flue gas flow;

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)

Abstract

La présente invention concerne un système qui se rapporte au domaine du génie mécanique. Le système bloque et profile le flux de gaz de combustion et augmente en outre les performances de transfert de chaleur d'échangeurs de chaleur. Selon l'invention, un séparateur cyclone est en communication fluidique avec une sortie de gaz de combustion d'une chambre de combustion et est conçu pour recevoir des particules de combustible et des gaz de combustion et séparer les particules de combustible des gaz de combustion. Un conduit de gaz de combustion est en communication fluidique avec le séparateur cyclone et est conçu pour recevoir les gaz de combustion provenant du séparateur cyclone et transporter les gaz de combustion vers une colonne d'échange de chaleur. Une section antitourbillon de gaz de combustion est placée à l'intérieur du conduit de gaz de combustion et comprend une membrane de mur d'eau. La membrane de mur d'eau profile le flux de gaz de combustion et résiste à ce dernier et présente une structure de type maillage.
PCT/IB2016/053814 2016-04-21 2016-06-27 Système de chaudière à lit fluidisé circulant WO2017182855A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PH12018502254A PH12018502254A1 (en) 2016-04-21 2018-10-22 A circulating fluidized bed boiler system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN201621013986 2016-04-21
IN201621013986 2016-04-21

Publications (1)

Publication Number Publication Date
WO2017182855A1 true WO2017182855A1 (fr) 2017-10-26

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PCT/IB2016/053814 WO2017182855A1 (fr) 2016-04-21 2016-06-27 Système de chaudière à lit fluidisé circulant

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PH (1) PH12018502254A1 (fr)
WO (1) WO2017182855A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101255005B1 (ko) * 2008-11-06 2013-04-17 포스터 휠러 에너지아 오와이 순환 유동층 보일러

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101255005B1 (ko) * 2008-11-06 2013-04-17 포스터 휠러 에너지아 오와이 순환 유동층 보일러

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PH12018502254A1 (en) 2019-08-19

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