CA2222958A1 - Method of and apparatus for treating process gases in a circulating fluidized bed - Google Patents
Method of and apparatus for treating process gases in a circulating fluidized bed Download PDFInfo
- Publication number
- CA2222958A1 CA2222958A1 CA002222958A CA2222958A CA2222958A1 CA 2222958 A1 CA2222958 A1 CA 2222958A1 CA 002222958 A CA002222958 A CA 002222958A CA 2222958 A CA2222958 A CA 2222958A CA 2222958 A1 CA2222958 A1 CA 2222958A1
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- Prior art keywords
- fluidized
- auxiliary
- gas
- bed
- gas flows
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
- F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
- F27B15/10—Arrangements of air or gas supply devices
-
- 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
- F23C10/20—Inlets for fluidisation air, e.g. grids; Bottoms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
- F23G5/30—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a fluidised bed
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
- F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J2215/00—Preventing emissions
- F23J2215/20—Sulfur; Compounds thereof
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J2215/00—Preventing emissions
- F23J2215/30—Halogen; Compounds thereof
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J2219/00—Treatment devices
- F23J2219/60—Sorption with dry devices, e.g. beds
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Combustion & Propulsion (AREA)
- Dispersion Chemistry (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
- Crucibles And Fluidized-Bed Furnaces (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Treating Waste Gases (AREA)
Abstract
Process gases, in particular process waste gases from refuse incineration, are introduced into a circulating fluidized bed from below via a venturi-nozzle-like inlet and form a core stream (K). Auxiliary-gas flows (H) are injected in a annular marginal zone (6) concentrically to the core stream (K) into the circulating fluidized bed. The fluidized-bed solid particles sinking to the bottom in marginal regions of the fluidized bed are thereby delivered into the core stream (K).
Description
CA 022229~8 1997-11-28 Method of and apparatus for treating process gases in a circulating fluidized bed The invention relates to a method according to the preamble of claim 1.
DE-A-33 07 848 discloses a method of this type. In this method, process waste gases, such as combustion gases containing combustible constituents, are fed via a venturi-nozzle-like charging device to a fluidized-bed reactor functioning according to the principle of a circulating fluidized bed and are subjected to secondary combustion there and cleaned.
Unlike the "classic" stationary fluidized bed, in which the phase containing solids is separated from the gas space above it by a distinct jump in density, the aim in this method, i.e. in the circulating fluidized bed, is to achieve distribution states of the circulating solid without a defined boundary layer, in which distribution states the concentration of solids within the reactor decreases from bottom to top.
A continuous decrease in the concentration of solids from bottom to top within the circulating fluidized bed is desired. It has not been possible hitherto to achieve this in circulating fluidized beds by means of a venturi-like charging device. It was noticed that solid particles sink to the bottom in the marginal regions of the fluidized bed and accumulate in the lowermost, narrowest region of the fluidized-bed reactor, which narrows conically toward the bottom.
These solid particles are then tossed around at this point and scarcely come into circulation. In particular in the treatment of process gases containing sticky components, e.g. molten solid such as fly ash, solid CA 022229~8 1997-11-28 agglomerations which can reach tennis ball size at this point are produced. The accumulation of solids in the bottom region of the fluidized-bed reactor produces a constriction at the inlet point in the fluidized-bed reactor, as a result of which the process-gas flow is constricted and accelerated. There is consequently less time available for the treatment of the process gases than intended. The ;nh~mogeneous distribution of the solid results in inadequate heat exchange and jumps in temperature in the reactor.
A further disadvantage of the known circulating venturi fluidized bed consists in the fact that the circulation of the solids is less than in a conventional fluidized bed.
It is known from US Patent 4,934,282 to develop a stationary fluidized bed for the combustion of solid fuels in such a way that a small portion of the fluidized-bed material is discharged from the reactor and recirculated. Apart from the co~mbustion air introduced centrally, additional air is blown from below via a plurality of inlet openings arranged in the bottom of the reactor into the phase containing solids in order to increase the otherwise only moderate motion of the solids in the fluidized bed. Nonetheless, in the case of this fluidized bed there is still a distinct jump in density between the bottom fluidized bed and the top gas space, and only a fraction of the solid comes into circulation.
The object of the present invention is to ~pecify a method of the type mentioned at the beginning as well as a fluidized-bed reactor for carrying out the method, having a suspension density of the residual CA 022229~8 1997-11-28 material particles which decreases continuously from bottom to top. This leads to improved heat exchange and a uniform temperature distribution.
This object is achieved according to the invention by the features specified in the defining part of claims 1 and 10.
Further preferred developments of the method according to the invention and of the fluidized-bed reactor for carrying out the method according to the invention are defined in the dependent claims.
It has surprisingly been found that, by reducing the inlet cross section of the process gas while simultaneously introducing auxiliary-gas flows concentrically in the remaining annular marginal zone, better intermixing of solid particles and process gases within the circulating fluidized bed and thus a continuous distribution of the solid particles are achieved. According to the invention, the constant distribution can even be optimized up to an approximately exponential distribution.
According to the invention, a circulation state in a circulating venturi fluidized bed is achieved, as is pre~ent in a conventional circulating fluidized bed having an incident-flow base fitted with nozzles. The circulation of the solids is increased more than 30-fold compared with the hitherto known venturi fluidized beds.
The term process gases refers to industrial gases, in particular those from refuse incineration. The treatment of such gases according to the invention involves, for example, cooling, dry cleaning (removal of HCl, SO2, etc.) and/or secondary combustion. The use of CA 022229~8 1997-11-28 a circulating fluidized bed for the cooling (quenching), dry cleaning or secondary co~mbustion of process gases from a furnace and its advantages are disclosed by the abovementioned DE-A-33 07 848. In this case, the process gases are used as fluidization gas; sand, an adsorbent and/or a reagent, for example, is used as fluidized-bed solid. In a preferred manner, however, the bed material is at least partly formed from the fly ash originating from the furnace. The bed material is distinguished as an excellent heat carrier, which, given a suitable distribution of solid particles, permits a uniform temperature distribution in the fluidized-bed reactor, the temperature being readily controllable in a manner known per se, e.g. via an external fluidized-bed cooler.
The possibilities offered by a circulating fluidized bed can be better utilized by the invention.
In particular, reactions and heat exchange, according to the invention, take place quicker as a result of the smooth, i.e. continuous, distribution of solid particles. Consequently, the dwell time can be reduced or the reactors can be of smaller ~;mensions.
The invention is explained in more detail below with reference to the drawing, in which, in purely schematic form:
Fig. 1 shows a vertical center section of a first exemplary embodiment of a bottom part of a fluidized-bed reactor for carrying out the method according to the invention, and Fig. 2 shows a vertical center section of a second exemplary embodiment of a bottom part of a fluidized-bed reactor for carrying out the method according to the invention.
- CA 022229~8 1997-11-28 According to Figs 1 and 2, a fluidized-bed reactor 1, 1', of which only the bottom part is shown in the drawing, has a diffuser region 2 which widens conically toward the top and into which a cylindrical duct 4 for introducing the process gases to be treated leads. The process gases forming a core stream K flow in the direction of the arrow through the cylindrical duct 4 into the fluidized-bed reactor 1, 1'. The diffuser region 2, together with the cylindrical duct 4 and a confuser 5 adjoining the latter at the bottom, forms a venturi-nozzle-like inlet for the process gases.
An annular marginal base zone 6 surrounding the duct 4 is arranged between the duct 4 and the diffuser wall 3 and forms the bottom closure of the diffuser region 2.
In the embodiment shown in Fig. 1, the outlet opening 8 of the cylindrical duct 4 is displaced relative to the marginal base zone 6 into the interior of the fluidized-bed reactor 1. In another variant, shown in Fig. 2, of a fluidized-bed reactor 1', the outlet opening 8' lies in the same plane as the marginal base zone 6.
According to Fig. 1, a plurality of base openings 10, preferably distributed uniformly about the duct 4, are arranged in the annular marginal base zone 6 concentrically to the duct 4, into which base openings nozzles 9 leading into the interior of the fluidized-bed reactor 1 are inserted. Via the nozzles 9, a plurality of auxiliary-gas flows, designated by arrows H, are injected concentrically into the fluidized-bed reactor 1 and preferably parallel to the core stream K issuing from the outlet opening 9.
- CA 022229~8 1997-11-28 In the variant shown in Fig. 2, the auxiliary-gas flows are injected via base openings 10' arranged in a plurality of circles concentrically about the duct 4, as a result of which uniform base fluidization in the annular marginal base zone 6 is achieved. It is of course also possible to simultaneously inject the auxiliary-gas flows via both the nozzles 9 and the base openings 10'. The auxiliary-gas flows can be formed either by an additional gas or partly or completely by the process gas. An oxygenous gas is advantageously fed, preferably with the auxiliary-gas flows H, in the case of secondary combustion taking place in the fluidized-bed reactor.
The invention is further illustrated with the aid of the following example.
Example Via twelve lances having a diameter of 10 mm, air was injected as auxiliary-gas flows at a rate of between 50 and 250 m /h in the normal state (corresponding to an outlet velocity of 15-75 m/s in the normal state) into the secondary-combustion chamber of a pilot plant for the secondary combustion of process gases. 15 to 50 m3/h in the normal state (correspo-n~;ng to a fluidization velocity of 0.08-0.27 m/s in the normal state) was injected with a further auxiliary-gas flow for the base fluidization. The flue-gas quantity entering the secondary-combustion chamber was 800 to 1400 m3/h in the normal state at a temperature of 1200~C
to 1600~C.
Typical values were a flue-gas quantity of 1200m3/h in the normal state and a temperature of 1500~C
CA 022229~8 1997-11-28 at an auxiliary-gas quanitity of 150 m3/h in the normal state introduced by lances and, if need be, a further auxiliary-gas quantity for the base fluidization of 15 m3/h in the normal state.
The ratio of the outside diameter of the marginal base zone 6 to the diameter of the duct 4 or the outlet opening 8 for the core stream is preferably 3:1 to 10:8. As already mentioned at the beg;nn;ng, it has been observed in methods according to the prior art that solid particles or the fly ash in marginal regions of the fluidized bed sinks to the bottom again on account of a gas return flow and the force of gravity.
Even the presence of the annular marginal base zone 6 around the duct 4 reduces the accumulation of solid particles in the bottom part of the reactor. According to the invention, the auxiliary-gas flows H introduced by means of nozzles 9 and/or base openings 10, 10' prevent these solid particles from accummulating in the bottom narrowed reactor part and being tossed around there. The auxiliary-gas flows H swirl up the solid particles again, break them up, hold them in suspension and deliver them into the core stream K without deposits and caking occurring. Any coarse ash can be discharged without problems (the coarse-ash discharge is designated by 11 and the discharge direction is designated by an arrow A in Figs 1 and 2). The coarse-ash discharge permits the optimization of the pressure drop in the fluidized-bed reactor. A smaller induced-draft capacity is thus required, which permits a simpler design of the plant. In addition, smoother operation, which is less dependent on pulsations in the process-gas feed, is achieved by the method according to the invention.
- CA 022229~8 1997-11-28 In the method according to the invention, both the solid-particle circulation directed internally and the solid-particle circulation directed externally are increased. The good m; ~; ng of solid particles into the core stream by means of auxiliary-gas flows produces a very good quenching effect (e.g. from 1600~C to 900~C).
This is of particular importance, for example, for the flue-gas cooling. The increase, mentioned above, in the solid-particle circulation also results in an increase in the heat energy obtainable in the fluidized-bed cooler and intended for further use.
High temperatures can be avoided during the secondary combustion, since the heat of combustion is dissipated virtually in situ as a result of the excellent gas/solid intermixing.
The essential advantage of the method according to the invention or of the fluidized-bed reactor according to the invention consists in bringing about a continuous ~uspension density distribution in the circulating fluidized bed with venturi-like inlet and consequently optimum process control within the circulating fluidized bed.
DE-A-33 07 848 discloses a method of this type. In this method, process waste gases, such as combustion gases containing combustible constituents, are fed via a venturi-nozzle-like charging device to a fluidized-bed reactor functioning according to the principle of a circulating fluidized bed and are subjected to secondary combustion there and cleaned.
Unlike the "classic" stationary fluidized bed, in which the phase containing solids is separated from the gas space above it by a distinct jump in density, the aim in this method, i.e. in the circulating fluidized bed, is to achieve distribution states of the circulating solid without a defined boundary layer, in which distribution states the concentration of solids within the reactor decreases from bottom to top.
A continuous decrease in the concentration of solids from bottom to top within the circulating fluidized bed is desired. It has not been possible hitherto to achieve this in circulating fluidized beds by means of a venturi-like charging device. It was noticed that solid particles sink to the bottom in the marginal regions of the fluidized bed and accumulate in the lowermost, narrowest region of the fluidized-bed reactor, which narrows conically toward the bottom.
These solid particles are then tossed around at this point and scarcely come into circulation. In particular in the treatment of process gases containing sticky components, e.g. molten solid such as fly ash, solid CA 022229~8 1997-11-28 agglomerations which can reach tennis ball size at this point are produced. The accumulation of solids in the bottom region of the fluidized-bed reactor produces a constriction at the inlet point in the fluidized-bed reactor, as a result of which the process-gas flow is constricted and accelerated. There is consequently less time available for the treatment of the process gases than intended. The ;nh~mogeneous distribution of the solid results in inadequate heat exchange and jumps in temperature in the reactor.
A further disadvantage of the known circulating venturi fluidized bed consists in the fact that the circulation of the solids is less than in a conventional fluidized bed.
It is known from US Patent 4,934,282 to develop a stationary fluidized bed for the combustion of solid fuels in such a way that a small portion of the fluidized-bed material is discharged from the reactor and recirculated. Apart from the co~mbustion air introduced centrally, additional air is blown from below via a plurality of inlet openings arranged in the bottom of the reactor into the phase containing solids in order to increase the otherwise only moderate motion of the solids in the fluidized bed. Nonetheless, in the case of this fluidized bed there is still a distinct jump in density between the bottom fluidized bed and the top gas space, and only a fraction of the solid comes into circulation.
The object of the present invention is to ~pecify a method of the type mentioned at the beginning as well as a fluidized-bed reactor for carrying out the method, having a suspension density of the residual CA 022229~8 1997-11-28 material particles which decreases continuously from bottom to top. This leads to improved heat exchange and a uniform temperature distribution.
This object is achieved according to the invention by the features specified in the defining part of claims 1 and 10.
Further preferred developments of the method according to the invention and of the fluidized-bed reactor for carrying out the method according to the invention are defined in the dependent claims.
It has surprisingly been found that, by reducing the inlet cross section of the process gas while simultaneously introducing auxiliary-gas flows concentrically in the remaining annular marginal zone, better intermixing of solid particles and process gases within the circulating fluidized bed and thus a continuous distribution of the solid particles are achieved. According to the invention, the constant distribution can even be optimized up to an approximately exponential distribution.
According to the invention, a circulation state in a circulating venturi fluidized bed is achieved, as is pre~ent in a conventional circulating fluidized bed having an incident-flow base fitted with nozzles. The circulation of the solids is increased more than 30-fold compared with the hitherto known venturi fluidized beds.
The term process gases refers to industrial gases, in particular those from refuse incineration. The treatment of such gases according to the invention involves, for example, cooling, dry cleaning (removal of HCl, SO2, etc.) and/or secondary combustion. The use of CA 022229~8 1997-11-28 a circulating fluidized bed for the cooling (quenching), dry cleaning or secondary co~mbustion of process gases from a furnace and its advantages are disclosed by the abovementioned DE-A-33 07 848. In this case, the process gases are used as fluidization gas; sand, an adsorbent and/or a reagent, for example, is used as fluidized-bed solid. In a preferred manner, however, the bed material is at least partly formed from the fly ash originating from the furnace. The bed material is distinguished as an excellent heat carrier, which, given a suitable distribution of solid particles, permits a uniform temperature distribution in the fluidized-bed reactor, the temperature being readily controllable in a manner known per se, e.g. via an external fluidized-bed cooler.
The possibilities offered by a circulating fluidized bed can be better utilized by the invention.
In particular, reactions and heat exchange, according to the invention, take place quicker as a result of the smooth, i.e. continuous, distribution of solid particles. Consequently, the dwell time can be reduced or the reactors can be of smaller ~;mensions.
The invention is explained in more detail below with reference to the drawing, in which, in purely schematic form:
Fig. 1 shows a vertical center section of a first exemplary embodiment of a bottom part of a fluidized-bed reactor for carrying out the method according to the invention, and Fig. 2 shows a vertical center section of a second exemplary embodiment of a bottom part of a fluidized-bed reactor for carrying out the method according to the invention.
- CA 022229~8 1997-11-28 According to Figs 1 and 2, a fluidized-bed reactor 1, 1', of which only the bottom part is shown in the drawing, has a diffuser region 2 which widens conically toward the top and into which a cylindrical duct 4 for introducing the process gases to be treated leads. The process gases forming a core stream K flow in the direction of the arrow through the cylindrical duct 4 into the fluidized-bed reactor 1, 1'. The diffuser region 2, together with the cylindrical duct 4 and a confuser 5 adjoining the latter at the bottom, forms a venturi-nozzle-like inlet for the process gases.
An annular marginal base zone 6 surrounding the duct 4 is arranged between the duct 4 and the diffuser wall 3 and forms the bottom closure of the diffuser region 2.
In the embodiment shown in Fig. 1, the outlet opening 8 of the cylindrical duct 4 is displaced relative to the marginal base zone 6 into the interior of the fluidized-bed reactor 1. In another variant, shown in Fig. 2, of a fluidized-bed reactor 1', the outlet opening 8' lies in the same plane as the marginal base zone 6.
According to Fig. 1, a plurality of base openings 10, preferably distributed uniformly about the duct 4, are arranged in the annular marginal base zone 6 concentrically to the duct 4, into which base openings nozzles 9 leading into the interior of the fluidized-bed reactor 1 are inserted. Via the nozzles 9, a plurality of auxiliary-gas flows, designated by arrows H, are injected concentrically into the fluidized-bed reactor 1 and preferably parallel to the core stream K issuing from the outlet opening 9.
- CA 022229~8 1997-11-28 In the variant shown in Fig. 2, the auxiliary-gas flows are injected via base openings 10' arranged in a plurality of circles concentrically about the duct 4, as a result of which uniform base fluidization in the annular marginal base zone 6 is achieved. It is of course also possible to simultaneously inject the auxiliary-gas flows via both the nozzles 9 and the base openings 10'. The auxiliary-gas flows can be formed either by an additional gas or partly or completely by the process gas. An oxygenous gas is advantageously fed, preferably with the auxiliary-gas flows H, in the case of secondary combustion taking place in the fluidized-bed reactor.
The invention is further illustrated with the aid of the following example.
Example Via twelve lances having a diameter of 10 mm, air was injected as auxiliary-gas flows at a rate of between 50 and 250 m /h in the normal state (corresponding to an outlet velocity of 15-75 m/s in the normal state) into the secondary-combustion chamber of a pilot plant for the secondary combustion of process gases. 15 to 50 m3/h in the normal state (correspo-n~;ng to a fluidization velocity of 0.08-0.27 m/s in the normal state) was injected with a further auxiliary-gas flow for the base fluidization. The flue-gas quantity entering the secondary-combustion chamber was 800 to 1400 m3/h in the normal state at a temperature of 1200~C
to 1600~C.
Typical values were a flue-gas quantity of 1200m3/h in the normal state and a temperature of 1500~C
CA 022229~8 1997-11-28 at an auxiliary-gas quanitity of 150 m3/h in the normal state introduced by lances and, if need be, a further auxiliary-gas quantity for the base fluidization of 15 m3/h in the normal state.
The ratio of the outside diameter of the marginal base zone 6 to the diameter of the duct 4 or the outlet opening 8 for the core stream is preferably 3:1 to 10:8. As already mentioned at the beg;nn;ng, it has been observed in methods according to the prior art that solid particles or the fly ash in marginal regions of the fluidized bed sinks to the bottom again on account of a gas return flow and the force of gravity.
Even the presence of the annular marginal base zone 6 around the duct 4 reduces the accumulation of solid particles in the bottom part of the reactor. According to the invention, the auxiliary-gas flows H introduced by means of nozzles 9 and/or base openings 10, 10' prevent these solid particles from accummulating in the bottom narrowed reactor part and being tossed around there. The auxiliary-gas flows H swirl up the solid particles again, break them up, hold them in suspension and deliver them into the core stream K without deposits and caking occurring. Any coarse ash can be discharged without problems (the coarse-ash discharge is designated by 11 and the discharge direction is designated by an arrow A in Figs 1 and 2). The coarse-ash discharge permits the optimization of the pressure drop in the fluidized-bed reactor. A smaller induced-draft capacity is thus required, which permits a simpler design of the plant. In addition, smoother operation, which is less dependent on pulsations in the process-gas feed, is achieved by the method according to the invention.
- CA 022229~8 1997-11-28 In the method according to the invention, both the solid-particle circulation directed internally and the solid-particle circulation directed externally are increased. The good m; ~; ng of solid particles into the core stream by means of auxiliary-gas flows produces a very good quenching effect (e.g. from 1600~C to 900~C).
This is of particular importance, for example, for the flue-gas cooling. The increase, mentioned above, in the solid-particle circulation also results in an increase in the heat energy obtainable in the fluidized-bed cooler and intended for further use.
High temperatures can be avoided during the secondary combustion, since the heat of combustion is dissipated virtually in situ as a result of the excellent gas/solid intermixing.
The essential advantage of the method according to the invention or of the fluidized-bed reactor according to the invention consists in bringing about a continuous ~uspension density distribution in the circulating fluidized bed with venturi-like inlet and consequently optimum process control within the circulating fluidized bed.
Claims (15)
1. A method of treating process gases, in particular from refuse incineration, in a circulating fluidized bed, the process gases being introduced into the fluidized bed from below via a venturi-nozzle-like inlet, wherein the process gases are introduced into the fluidized bed in a core stream (K) and at the same time auxiliary-gas flows (H) are injected in an annular marginal zone (6) concentrically to the core stream (K) into the circulating fluidized bed in such a way that fluidized-bed solid particles sinking to the bottom in marginal regions of the circulating fluidized bed are delivered into the core stream (K).
2. The method as claimed in claim 1, wherein the auxiliary-gas flows (H) are injected parallel to the core stream (K).
3. The method as claimed in claim 1 or 2, wherein the process gas is used at least partly as auxiliary gas.
4. The method as claimed in claim 1 or 2, wherein a further gas is used as auxiliary gas.
5. The method as claimed in one of claims 1 to 4, wherein the ratio of the outside diameter of the annular marginal zone (6) to the diameter of the core stream (K) is 3:1 to 10:8.
6. The method as claimed in one of claims 1 to 5, wherein uniform base fluidization is effected in the annular marginal zone (6) by means of the auxiliary-gas flows (H), the average velocity of the auxiliary-gas flows (H) over the base area of the marginal zone preferably being 0.05 to 0.3 m/s, calculated under normal conditions.
7. The method as claimed in one of claims 1 to 6, wherein a portion of the auxiliary-gas flows (H) is injected at an outlet velocity of 15 to 75 m/s, calculated under normal conditions.
8. The method as claimed in one of claims 1 to 7, wherein, to carry out dry-gas cleaning, solid particles containing a reagent and/or an adsorption medium are used in the circulating fluidized bed.
9. The method as claimed in one of claims 1 to 7, wherein an oxygenous gas, preferably in the form of auxiliary-gas flows (H), is introduced in order to carry out secondary combustion.
10. A fluidized-bed reactor (1, 1') for carrying out the method as claimed in claim 1, having a diffuser region (2) which widens conically toward the top and forms together with a cylindrical duct (4) and a confuser (5) a venturi-nozzle-like inlet for the process gases, wherein there is an annular marginal base zone (6) between the duct (4) and the diffuser wall (3), which marginal base zone (6) has a plurality of uniformly distributed base openings (10, 10') arranged concentrically to the cylindrical duct (4) and intended for injecting the auxiliary-gas flows (H).
11. The fluidized-bed reactor as claimed in claim 10, wherein at least some of the base openings (10) are provided with nozzles (9) for injecting the auxiliary-gas flows (H).
12. The fluidized-bed reactor as claimed in claim 10 or 11, wherein the base openings (10') are arranged in a plurality of circles concentric to the cylindrical duct (4).
13. The fluidized-bed reactor as claimed in one of claims 10 to 12, wherein the cylindrical duct (4) projects into the diffuser region (2).
14. The fluidized-bed reactor as claimed in one of claims 10 to 12, wherein the cylindrical duct (4) is flush with the marginal base zone (6) on the diffuser side.
15. The fluidized-bed reactor as claimed in one of claims 10 to 14, wherein a coarse-ash discharge (11) is arranged above the marginal base zone (6) in the bottom diffuser region (2).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH320096 | 1996-12-30 | ||
| CH19963200/96 | 1996-12-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2222958A1 true CA2222958A1 (en) | 1998-06-30 |
Family
ID=4250827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002222958A Abandoned CA2222958A1 (en) | 1996-12-30 | 1997-11-28 | Method of and apparatus for treating process gases in a circulating fluidized bed |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0851175B1 (en) |
| JP (1) | JP3082035B2 (en) |
| KR (1) | KR100271123B1 (en) |
| AT (1) | ATE216476T1 (en) |
| CA (1) | CA2222958A1 (en) |
| CZ (1) | CZ293171B6 (en) |
| DE (1) | DE59707042D1 (en) |
| ES (1) | ES2121717T1 (en) |
| HU (1) | HUP9702470A3 (en) |
| NO (1) | NO976155L (en) |
| PL (1) | PL324068A1 (en) |
| TW (1) | TW354363B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9134022B2 (en) | 2008-10-30 | 2015-09-15 | Karlsruher Institut Fuer Technologie | Method and device for reducing hazardous emissions in internal combustion systems |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101881458B (en) * | 2010-07-16 | 2012-11-14 | 李登平 | Combustion device for treating waste gas of waste incineration |
| CN110513705B (en) * | 2018-05-21 | 2024-03-15 | 安德森热能科技（苏州）有限责任公司 | A adjustable combustor of regulation ratio for waste gas burns |
| KR102422089B1 (en) * | 2019-02-28 | 2022-07-18 | 주식회사 엘지화학 | Fluidized Bed Reactor |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3398718A (en) * | 1965-03-10 | 1968-08-27 | Atomic Energy Commission Usa | Fluidized-bed coating apparatus |
| US4065271A (en) * | 1973-09-15 | 1977-12-27 | Metallgesellschaft Aktiengesellschaft | Process of separating hydrogen fluoride from gases |
| US4191544A (en) * | 1978-03-17 | 1980-03-04 | The Babcock & Wilcox Company | Gas cleaning apparatus |
| JPS5568506A (en) * | 1978-11-20 | 1980-05-23 | Babcock Hitachi Kk | Rotating fluidized bed furnace |
| DE3307848A1 (en) | 1983-03-05 | 1984-09-06 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR REBURNING AND PURIFYING PROCESS EXHAUST GAS |
| DE3526008A1 (en) * | 1985-07-20 | 1987-01-22 | Metallgesellschaft Ag | METHOD FOR REMOVING POLLUTANTS FROM SMOKE GAS |
| JPH01210795A (en) | 1988-02-18 | 1989-08-24 | Ishikawajima Harima Heavy Ind Co Ltd | Powder burning bed and circulating fluidized bed combustion device |
| US4940007A (en) * | 1988-08-16 | 1990-07-10 | A. Ahlstrom Corporation | Fast fluidized bed reactor |
| FR2644795B1 (en) * | 1989-03-24 | 1993-12-17 | Institut Francais Petrole | METHOD AND DEVICE FOR INJECTING THE HYDROCARBON LOAD IN A FLUID CATALYTIC CRACKING PROCESS |
| JP3099530B2 (en) * | 1992-06-22 | 2000-10-16 | 川崎重工業株式会社 | Spouted bed refuse incinerator |
| US5422080A (en) * | 1994-03-09 | 1995-06-06 | Tampella Power Corporation | Solids circulation enhancing air distribution grid |
| DE19510212A1 (en) * | 1995-03-21 | 1996-09-26 | Graf Epe Gmbh | Gas inlet for supplying gas to a container |
-
1997
- 1997-11-28 CA CA002222958A patent/CA2222958A1/en not_active Abandoned
- 1997-12-08 DE DE59707042T patent/DE59707042D1/en not_active Expired - Fee Related
- 1997-12-08 EP EP97121573A patent/EP0851175B1/en not_active Expired - Lifetime
- 1997-12-08 ES ES97121573T patent/ES2121717T1/en active Pending
- 1997-12-08 AT AT97121573T patent/ATE216476T1/en not_active IP Right Cessation
- 1997-12-12 HU HU9702470A patent/HUP9702470A3/en unknown
- 1997-12-26 JP JP09359693A patent/JP3082035B2/en not_active Expired - Lifetime
- 1997-12-26 TW TW086119791A patent/TW354363B/en active
- 1997-12-29 KR KR1019970076670A patent/KR100271123B1/en not_active IP Right Cessation
- 1997-12-29 PL PL97324068A patent/PL324068A1/en unknown
- 1997-12-30 CZ CZ19974229A patent/CZ293171B6/en not_active IP Right Cessation
- 1997-12-30 NO NO976155A patent/NO976155L/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9134022B2 (en) | 2008-10-30 | 2015-09-15 | Karlsruher Institut Fuer Technologie | Method and device for reducing hazardous emissions in internal combustion systems |
Also Published As
| Publication number | Publication date |
|---|---|
| HUP9702470A2 (en) | 1999-07-28 |
| CZ293171B6 (en) | 2004-02-18 |
| JPH10206028A (en) | 1998-08-07 |
| EP0851175B1 (en) | 2002-04-17 |
| EP0851175A1 (en) | 1998-07-01 |
| ES2121717T1 (en) | 1998-12-16 |
| NO976155D0 (en) | 1997-12-30 |
| HUP9702470A3 (en) | 1999-12-28 |
| DE59707042D1 (en) | 2002-05-23 |
| ATE216476T1 (en) | 2002-05-15 |
| KR19980064781A (en) | 1998-10-07 |
| JP3082035B2 (en) | 2000-08-28 |
| KR100271123B1 (en) | 2000-12-01 |
| CZ422997A3 (en) | 1998-11-11 |
| NO976155L (en) | 1998-07-01 |
| PL324068A1 (en) | 1998-07-06 |
| TW354363B (en) | 1999-03-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |