WO1996012915A1 - Procede et dispositif destines a alimenter un lit fluidise en un produit absorbant - Google Patents

Procede et dispositif destines a alimenter un lit fluidise en un produit absorbant Download PDF

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Publication number
WO1996012915A1
WO1996012915A1 PCT/SE1995/001223 SE9501223W WO9612915A1 WO 1996012915 A1 WO1996012915 A1 WO 1996012915A1 SE 9501223 W SE9501223 W SE 9501223W WO 9612915 A1 WO9612915 A1 WO 9612915A1
Authority
WO
WIPO (PCT)
Prior art keywords
bed
absorbent
fraction
coarse fraction
combustor
Prior art date
Application number
PCT/SE1995/001223
Other languages
English (en)
Inventor
Roine Brännström
Original Assignee
Abb Carbon Ab
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 Abb Carbon Ab filed Critical Abb Carbon Ab
Publication of WO1996012915A1 publication Critical patent/WO1996012915A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/0015—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor
    • B01J8/003—Feeding of the particles in the reactor; Evacuation of the particles out of the reactor in a downward flow
    • 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
    • F23C10/16—Fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures, e.g. by the arrangement of the combustion chamber and its auxiliary systems inside a pressure vessel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/32—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with introduction into the fluidised bed of more than one kind of moving particles
    • 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
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J7/00—Arrangement of devices for supplying chemicals to fire
    • 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 
    • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/10001—Use of special materials for the fluidized bed

Definitions

  • the present invention relates to a plant for combustion of solid particulate fuel in a fluidized bed which is supplied with an absorbent with a varying grain size, wherein coarser and finer fractions are supplied separately to the bed.
  • the presence of certain impurities, preferably sulphur, in the combustion gases generated during combustion of the fuel must be taken into consideration, which entails environmental drawbacks.
  • One advantage with the combustion of the fuel taking place in a fluidized bed is that the material of the bed may be supplied with an absorbing substance, an absorbent, for example lime ⁇ stone or dolomite, which reacts with and binds the above- mentioned impurities such that these, in the form of harmless grain, powder or sludge, may be deposited.
  • the absorbent may be fed into the bed in dry state.
  • the feeding of absorbent mixed into a paste, which consists of fuel and a liquid, is also frequently used in prior art plants.
  • a pneumatic method of transport is energy-demanding in, for example, a pressurized fluidized bed since the consumption of transport gas is substantial.
  • the present invention relates to a method and a device for combustion of a particulate fuel in a fluidized bed enclosed in a combustor, wherein impurities in the combustion gases generated during the combustion are absorbed by an absorbent which is supplied in particle shape to the combustor.
  • the method comprises
  • the degree of utilization of the coarse fraction of the absor ⁇ bent becomes higher since the grains are large and remain long in the bed (3-8 hours) , whereby the absorbent grains have time to sulphate in full before leaving the bed.
  • the long residence time for the coarse grains of the absorbent further means that a continuous feeding of the coarse fraction may be omitted, whereby, for example, lock-hopper devices and similar mechanical means may be omitted.
  • Very suited for feed- ing of the coarse fraction of absorbent in a pressurized com ⁇ bustor is an open absorbent container with a particle column standing under the container and opening out at the bed sur ⁇ face. Such a device completely without mechanical propulsion members for the particulate material is described in the patent application SE 9200696-4 (PCT/SE93/00102) .
  • the coarse fraction may be supplied via a non- insulated supply conduit which has a long extension through the freeboard of the combustor. This results in the advantage of the absorbent grains being preheated during their residence time in the supply conduit, the heating of the grains thus being performed less abruptly than when the prior art absor- bent is fed a short distance directly into the hot bed. Also this more slow heating of the absorbent particles contributes to a reduced risk of grain bursting according to the above.
  • Feeding of the coarse fraction of the absorbent into the upper part of the bed further entails advantages also when feeding the fraction when the combustion in the bed is performed under low-load conditions.
  • the bed surface is usually lowered while at the same time a low tem ⁇ perature and a high C ⁇ 2 content prevail at the bed surface, both of these conditions being favourable for avoiding grain bursting.
  • the fine fraction of the absorbent material must be well distributed in the lower part of the bed.
  • the fine fraction of the absorbent may be mixed into the paste, thus obtaining a good distribution of the fine fraction of the absorbent.
  • mixing the absorbent with the fuel provides an optimum result.
  • the fine fraction of the absorbent also serves as a drying agent for the fuel (coal) .
  • such mixing reduces the risk of explosion when handling the fuel.
  • the outlet nozzle for the coarse fraction of the absorbent grains is arranged at the bed surface and, for example, con ⁇ sists of an L valve of a known kind, where the flow of absor ⁇ bent may be controlled by a pulsed air or gas flow through the L valve. It is possible to dispose the nozzle also above the bed surface. The large grains fall down into the bed because of their weight.
  • Figure 1 shows a diagram of the degree of utilization of absorbent as a function of the diameter of the absorbent grains.
  • Figure 2 shows a schematic view of a PFBC combustor with a surrounding pressure vessel, where feeding of the coarse fraction of absorbent according to the invention is applied.
  • Figure 3 shows a variant of the feeding of absorbent to a PFBC combustor, where the coarse fraction is fed in via feeding means which do not comprise any mechanical device for taking up pressure differences.
  • Figure 4 shows an L valve at the orifice of the feed pipe for the absorbent.
  • FIG. 2 the central units of a PFBC power plant are represented, wherein a combustor 1 is accommodated in a pressure vessel 2. Air from a compressor (not shown) is supplied to the pressure vessel 2 at the air inlet 3 for pressurization of the pressure vessel 2 and hence also of the combustor 1. The compressed air 4 is supplied to the combustor 1 via fluidization nozzles 5 at the bottom of the combustor for fluidization of a bed 6 enclosed in the combustor.
  • the bed consists of bed material, particulate absorbent and a parti ⁇ culate fuel which is burnt in the fluidizing air 4 supplied to the bed 6.
  • Combustion gases from the bed 6 pass through a freeboard 7 above the bed surface 8 and are forwarded via the outlet 9 for cleaning in dust cleaners, whereafter the com ⁇ bustion gases are expanded in a gas turbine (not shown) , where the energy contents in the gases are transformed into useful energy.
  • a tube bundle 10 which is completely immersed in the bed at full-load opera ⁇ tion. Water is brought to the tube bundle 10 at 11 for genera ⁇ tion of steam in the tubes in the tube bundle. The steam is passed on at 12 to a steam turbine (not shown) in a steam cycle in the plant.
  • the coarse fraction may be fed further to a closed container 16, which is pressurized via a valve 18 in a connection conduit between the pressure vessel 2 and the container 16.
  • the absorbent is passed out from the pressurized container 16 via a feed conduit 17 to a region in the free ⁇ board 7 near the bed surface 8.
  • the outlet 19 from the feed conduit 17 may be formed as an L valve according to Figure 4 with the orifice 20 of the valve located immediately above, at or immediately below the surface 8 of the bed.
  • a standing particle column 21 of absorbent grains will form.
  • Supply of air or gas to the inlet pipe 22 may, for example, be performed by discharging air via a channel which puts the inlet pipe 22 in connection with the pressure vessel 2, the air quantity thus being controlled by means of a valve 22a in the channel.
  • Figure 3 describes another preferred feeding of absorbent, wherein the above-mentioned advantages of a long extension of the feed pipe 17 is utilized.
  • the combustor 1 is provided with a freeboard 7' which is extended in the vertical direction via a duct 25.
  • the feed pipe 17 for the coarse fraction of absorbent inside and along this extended freeboard 7' , the advantage of an extra long distance is obtained under which the absorbent in the feed pipe is pre ⁇ heated before it reaches the hot bed 6.
  • a container 30 which is under a lower pressure is utilized, for example an open container which is hence subjected to atmospheric pressure, for storage of the coarse fraction of absorbent.
  • the con ⁇ tainer 30 is provided at its lower part with a decreasing cross-section area and is transformed at its narrowest part into the feed pipe 17.
  • a particle column 31 formed in the container 30 and the pipe 17 is capable of taking up the pressure difference between the pressure in the combustor 1 and the pressure prevailing across the absorbent surface in the container 30.
  • a fine fraction of the absorbent which according to the invention is crushed into grain sizes smaller than 50 ⁇ , is fed in via the same conduits through which the fuel is fed into the bed 6, in the figures symbolized by fuel conduits 35 leading to the lower part of the bed 6.
  • the fuel which is fed into the combustor in a plant according to the invention may be fed in in arbitrary shape.
  • the fuel may be crushed or dried, in which case pneu- matic feeding is used.
  • Fuel may also be fed in in the form of a paste where the liquid fraction consists of water or oil. Also combinations of these methods may occur (see, for example, patent specification SE 90003542) .

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)

Abstract

L'invention se rapporte à la combustion d'un combustible particulaire dans un lit fluidisé (6) enfermé dans un brûleur (1), dans lequel les impuretés dans les gaz de combustion générés au cours de la combustion sont absorbées par un produit absorbant qui est introduit sous une forme particulaire dans le brûleur (1). Le procédé selon l'invention consiste à broyer les particules absorbantes dont le diamètre est inférieur à 0,4 mm en une fraction fine présentant une granulométrie telle que le diamètre des grains soit inférieur à 50 νm, après quoi cette fraction fine est introduite dans la partie inférieure du lit (6), les particules absorbantes dont la taille dépasse 0,4 mm, en d'autres termes, la fraction grossière, étant introduites dans la partie supérieure du lit (6), à proximité de sa surface (8).
PCT/SE1995/001223 1994-10-19 1995-10-18 Procede et dispositif destines a alimenter un lit fluidise en un produit absorbant WO1996012915A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9403568-0 1994-10-19
SE9403568A SE9403568A0 (sv) 1994-10-19 1994-10-19 Förfarande och anordning för inmatning av absorbent i en fluidiserad bädd

Publications (1)

Publication Number Publication Date
WO1996012915A1 true WO1996012915A1 (fr) 1996-05-02

Family

ID=20395663

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1995/001223 WO1996012915A1 (fr) 1994-10-19 1995-10-18 Procede et dispositif destines a alimenter un lit fluidise en un produit absorbant

Country Status (2)

Country Link
SE (1) SE9403568A0 (fr)
WO (1) WO1996012915A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020219625A1 (fr) * 2019-04-25 2020-10-29 Saint-Gobain Ceramics & Plastics, Inc. Particules adsorbantes et procédés de formation associés

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4421036A (en) * 1981-02-19 1983-12-20 Stal-Laval Turbine Ab Plant for the combustion of impure solid fuel
US4476790A (en) * 1979-04-23 1984-10-16 Combustion Engineering, Inc. Method of feeding particulate material to a fluidized bed
US4936770A (en) * 1988-11-25 1990-06-26 Foster Wheeler Energy Corporation Sulfur sorbent feed system for a fluidized bed reactor
WO1991011659A1 (fr) * 1990-02-01 1991-08-08 Abb Stal Ab Procede permettant d'alimenter un bruleur en produit absorbant le charbon et le soufre, et centrale electrique dans laquelle le procede est applique
EP0517495A2 (fr) * 1991-06-03 1992-12-09 Foster Wheeler Energy Corporation Procédé de combustion à lit fluidisé utilisant une charge contenant des particules d'absorbant fines et grosses
WO1993018344A1 (fr) * 1992-03-06 1993-09-16 Abb Carbon Ab Procede et dispositif permettant d'alimenter une enceinte sous pression en materiau a particules
DE4341389C1 (de) * 1993-12-04 1995-01-19 Rheinische Braunkohlenw Ag Fallrohr zum Eintragen von Kohle in einen Wirbelschicht-Vergaser

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4476790A (en) * 1979-04-23 1984-10-16 Combustion Engineering, Inc. Method of feeding particulate material to a fluidized bed
US4421036A (en) * 1981-02-19 1983-12-20 Stal-Laval Turbine Ab Plant for the combustion of impure solid fuel
US4936770A (en) * 1988-11-25 1990-06-26 Foster Wheeler Energy Corporation Sulfur sorbent feed system for a fluidized bed reactor
WO1991011659A1 (fr) * 1990-02-01 1991-08-08 Abb Stal Ab Procede permettant d'alimenter un bruleur en produit absorbant le charbon et le soufre, et centrale electrique dans laquelle le procede est applique
EP0517495A2 (fr) * 1991-06-03 1992-12-09 Foster Wheeler Energy Corporation Procédé de combustion à lit fluidisé utilisant une charge contenant des particules d'absorbant fines et grosses
WO1993018344A1 (fr) * 1992-03-06 1993-09-16 Abb Carbon Ab Procede et dispositif permettant d'alimenter une enceinte sous pression en materiau a particules
DE4341389C1 (de) * 1993-12-04 1995-01-19 Rheinische Braunkohlenw Ag Fallrohr zum Eintragen von Kohle in einen Wirbelschicht-Vergaser

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 12, No. 181, C-49; & JP,A,62 289 231 (MITSUBISHI HEAVY IND LTD), 16 December 1987. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020219625A1 (fr) * 2019-04-25 2020-10-29 Saint-Gobain Ceramics & Plastics, Inc. Particules adsorbantes et procédés de formation associés
US11666885B2 (en) 2019-04-25 2023-06-06 Saint-Gobain Ceramics & Plastics, Inc. Adsorbent particles and methods of forming thereof

Also Published As

Publication number Publication date
SE9403568A0 (sv) 1996-04-20
SE9403568L (fr) 1900-01-01
SE9403568D0 (sv) 1994-10-19

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