GB2315431A - Fluidised bed furnaces - Google Patents

Fluidised bed furnaces Download PDF

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Publication number
GB2315431A
GB2315431A GB9615418A GB9615418A GB2315431A GB 2315431 A GB2315431 A GB 2315431A GB 9615418 A GB9615418 A GB 9615418A GB 9615418 A GB9615418 A GB 9615418A GB 2315431 A GB2315431 A GB 2315431A
Authority
GB
United Kingdom
Prior art keywords
chamber
furnace
ring
fuel
blades
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
GB9615418A
Other versions
GB9615418D0 (en
GB2315431B (en
Inventor
Jacek Antoni Kostuch
Christopher Edward Dodson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Imerys Minerals Ltd
Mortimer Technology Holdings Ltd
Original Assignee
Mortimer Technology Holdings Ltd
ECC International Ltd
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 Mortimer Technology Holdings Ltd, ECC International Ltd filed Critical Mortimer Technology Holdings Ltd
Priority to GB9615418A priority Critical patent/GB2315431B/en
Publication of GB9615418D0 publication Critical patent/GB9615418D0/en
Priority to DK97932948T priority patent/DK0914201T3/en
Priority to PT97932948T priority patent/PT914201E/en
Priority to DE69706993T priority patent/DE69706993T2/en
Priority to JP50671998A priority patent/JP4115533B2/en
Priority to ES97932948T priority patent/ES2164360T3/en
Priority to BR9710516-3A priority patent/BR9710516A/en
Priority to AU36306/97A priority patent/AU730499B2/en
Priority to CA002261230A priority patent/CA2261230C/en
Priority to PCT/GB1997/002000 priority patent/WO1998003256A1/en
Priority to AT97932948T priority patent/ATE206071T1/en
Priority to EP97932948A priority patent/EP0914201B1/en
Priority to US09/214,951 priority patent/US6139313A/en
Publication of GB2315431A publication Critical patent/GB2315431A/en
Application granted granted Critical
Publication of GB2315431B publication Critical patent/GB2315431B/en
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

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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
    • B01J8/18—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
    • B01J8/38—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 fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it
    • B01J8/384—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 fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only
    • B01J8/386—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 fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only internally, i.e. the particles rotate within the 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
    • B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis
    • B01J6/001—Calcining
    • 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
    • B01J8/1836—Heating and cooling the reactor
    • 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
    • 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
    • F23C10/22—Fuel feeders specially adapted for fluidised bed combustion apparatus
    • 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
    • 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
    • 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
    • F27B15/14—Arrangements of heating devices
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00026—Controlling or regulating the heat exchange system
    • B01J2208/00035—Controlling or regulating the heat exchange system involving measured parameters
    • B01J2208/00044—Temperature measurement
    • B01J2208/00061—Temperature measurement of the reactants
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00026—Controlling or regulating the heat exchange system
    • B01J2208/00035—Controlling or regulating the heat exchange system involving measured parameters
    • B01J2208/00088—Flow rate measurement
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00106—Controlling the temperature by indirect heat exchange
    • B01J2208/00265—Part of all of the reactants being heated or cooled outside the reactor while recycling
    • B01J2208/00274—Part of all of the reactants being heated or cooled outside the reactor while recycling involving reactant vapours
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00327—Controlling the temperature by direct heat exchange
    • B01J2208/00336—Controlling the temperature by direct heat exchange adding a temperature modifying medium to the reactants
    • B01J2208/00353—Non-cryogenic fluids
    • B01J2208/00371—Non-cryogenic fluids gaseous
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00327—Controlling the temperature by direct heat exchange
    • B01J2208/00336—Controlling the temperature by direct heat exchange adding a temperature modifying medium to the reactants
    • B01J2208/0038—Solids
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00477—Controlling the temperature by thermal insulation means
    • B01J2208/00495—Controlling the temperature by thermal insulation means using insulating materials or refractories
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/0053—Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling

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)
  • Dispersion Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)

Abstract

Hot fluidising gas is introduced into a bed of material to be treated along the line of arrow "X". Below the bed it passes through a ring of blades 21, which are at an angle to the vertical in order to introduce a toroidal, circular flow to the gas and particles. More particles can be added through the radial tubes 23. In order to avoid the build-up of fused solid on the blades 21, the zone of greatest heating is caused to be well above them. To this effect, fuel is introduced via pipe 49 and radial pipes 45, which are angled upwards at their outer ends, so clearing the blades 21. This reacts (burns) with the hot fluidising gas (eg air), so producing the heat required for the treatment.

Description

FURNACES The present invention relates to furnaces. In particular, it relates to furnaces of the kind in which a toroidal fluid flow heating zone is established. Such furnaces are described for example in USP 4,479,920.
Generally, a hot gas is passed through gaps between angled blades or vanes in a ring of blades or vanes provided in the operational chamber of the furnace. The blade ring is formed in an annular gap between the wall of the chamber and a central block, eg. an upwardly pointing conical portion, located on the axis of the chamber. Gas flow is caused to follow a rotary path in a doughnut shaped region around the block and in individual swirls within the rotary path. This ensures efficient residence of and heat transfer to material, eg.
particulate material, to be heated in the gas flow.
Furnaces of the said kind may be used for the heat treatment of particulate material. However, we have found that where the feed particulate material comprises material which fluxes at temperatures at which it is to be heat treated unwanted build up, of the fluxed material occurs in various parts of the furnace, especially on or around the ring of angled blades. As illustrated hereinafter, such build up can cause a back pressure to occur which impedes the particulate feed system and/or extinguishes the burner employed to provide hot gas.
Such build-up of material requires removal before the furnace can be suitably operated again. This necessitates termination of the process of use of the furnace and undesirably limits the duration of the process of use. Such limitation makes prior art furnaces of the said kind unsuitable for some continuous heat treatment processes.
In any event, where a rapid throughput of material is required to be processed, the energy demands of the furnace are considerably raised and hot gas at a temperature as high as 16000C to 17000C might need to be delivered via the ring of angled blades. Such high temperatures can cause damage to the ring.
According to the present invention there is provided a furnace of the kind in which a toroidal fluid flow heating zone may be established, the furnace including a chamber in which there is provided an inner block, and a ring of angled blades between the inner block and the inner wall of the chamber, means for delivering fluid into the chamber whereby the fluid passes through gaps between the said blades and establishes a toroidal fluid flow heating zone in the chamber above the ring of angled blades and means for injecting into the chamber in the region where the toroidal fluid flow is to be established feed particulate material and characterised in that the furnace includes means for injecting fuel into the said chamber in the region above the ring of angled blades whereby the region in the chamber at which the heating zone in the chamber is established may be elevated above and beyond the ring of angled blades.
The fuel injected by such means may be reacted with a reacting fluid delivered into the said chamber in the usual manner through the gaps between the angled blades.
For example, the fuel may be a combustible fuel and the reacting fluid may be air or an oxygen containing fluid, whereby, if sufficient oxygen is available at a suitable elevated temperature, spontaneous reaction of the fuel and oxygen takes place to provide the required heating zone. This may constitute a plasma in part of, eg in the upper part of, the toroidal flow.
The advantage of the present invention is that the delivery of excessively hot gas to the operational chamber via the ring of angled blades can be avoided.
This avoids damage to the ring of angled blades and neighbouring components and also avoids unwanted accretion of material being processed on the hot surfaces.
The said reacting fluid may be delivered in a particular method of use of the invention at a temperature in the range 7000C to 9000C, especially 7000C to 8000C to provide a heating zone temperature of from 7500C to 105000, eg. 9200C to 102000.
The means for injecting fuel in the invention may comprise a ring of fuel inlet tubes extending from a common joint or housing to which input fuel is applied via an inlet pipe, the inlet tubes ending in the operational chamber. Preferably, the tubes are upwardly pointing at their ends in the chamber providing jets of fuel which are injected into the main fluid flow to provide combustion to form the required heating zone, eg.
by the said plasma.
The main fluid flow may comprise air which is preheated before delivery into the operational chamber through the gaps in the ring of angled blades. The heated air flow may be provided by combining with an excess supply of air a burning pre-heating fuel and exhaust gases produced by burning the pre-heating fuel.
The fuel which may be employed to provide preheating of the air flow and the fuel which may be injected directly into the operational chamber in the furnace according to the present invention may be the same or different fuels. Preferably, the two fuels are the same.
The fuel employed in the operation of the furnace according to the present invention by delivery via the said means for injecting fuel may be natural gas. It could alternatively comprise fuel oil, pulverised coal, or combustibles obtained from lignitic materials.
In a method of use of the furnace according to the present invention the feed material may comprise a particulate material of a kind which fluxes at temperatures above about 8000C. For example, the feed material may comprise mineral particles, eg. clay such as kaolin, calcium carbonate or mica to be flash calcined using the furnace. Heat treatment of such materials in a furnace of the kind in which a toroidal fluid flow heating zone is established is the subject of a further copending UK Patent Application of even date by the present Applicants. The furnace may be adjusted so that the temperature of calcination is in the range 7500C to 10500C, eg. 9200C to 10200C.
By carrying out heat treatment of such a material in the furnace according to the present invention it is possible to avoid the aforementioned problems of damage to the ring of angled blades and build-up of feed material and material produced therefrom contributing to the requirement for stoppage of the process and cleaning of the operational chamber of the furnace.
The temperature inside the operational chamber may be monitored. The rate of delivery of the fuel and/or the reacting fluid may be controlled by adjustment according to variations of the monitored temperature from a required norm representing the required heating zone temperature.
By carrying out heat treatment of such a material in the furnace according to the present it is possible to avoid the problems of damage to the ring of angled blades and unwanted build-up of feed material and material produced therefrom on and around the ring of angled blades.
We have found that in the heat treatment of particulate materials of a kind which flux when heated, the above described problem of the build up of feed material and material produced by heating such material which occurs in prior art furnaces of the kind producing a toroidal fluid flow is caused by the following effect.
Various critical internal surfaces in the furnace tend to overheat and thereby cause feed particulate material to adhere to such surfaces by fluxing/sintering at such surfaces. This problem is especially prevalent at the ring of angled blades.
The furnace according to the present invention beneficially prevents such overheating occurring, especially in the region of and adjacent to the ring of angled blades. The application of fuel through the said further inlet means allows the heating zone provided by the toroidal fluid flow to be moved upwardly away from the ring of blades and the regions of the chamber wall and the inner block immediately above the ring of blades thereby preventing overheating of the surfaces of these members.
Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a cross-sectional side elevation of a prior art furnace of the kind producing a toroidal fluid flow heating zone.
Figure 2 is a cross-sectional side elevation of part of a furnace of the kind producing a toroidal fluid flow heating zone, the furnace embodying the present invention.
A prior art furnace producing a fluid flow of the toroidal kind is shown in Figure 1. An enclosure 1 has a top 2, a base 3 and a side wall 4. A structure 5 made of refractory material comprising stacked annular portions 5a, 5b, 5c, 5d and 5e is supported by the base 3. An annular refractory portion 6 is provided between the portions 5a and 5b and an annular refractory portion 8 is provided between the portions 5a, Sb and Sc and covers an opening 4a in the side wall 4 whereby a passage 7 is provided inside the structure 5, the passage 7 communicating with a pipe 9 fitted to the side wall 4 at the opening 4a.
A tubular support 11 extends upwardly from the portion 6 through the passage 7. The support 11 carries a frusto-conical refractory portion 13 having an internal axial bore 14 and a refractory portion 15 located on top of the portion 13 by a portion 15a which engages within the top of the bore 14. A support 17 is attached to the tubular support 11 near its upper end and to a flange 19 extending into the passage 7 from the portion 5c. A ring 21 of angled blades is provided in the narrow gap between the lower end of the portion 13 and the outer portion 5d.
The blades are of the form described in USP 4,479,920.
The ring 21 is supported between the portion 5d and the support 17.
The uppermost refractory portion 5e in the structure 5 is fitted to an outlet chamber 25 whereby the chamber 7a communicates with the outlet chamber 25. An outlet pipe 28 extends from the outlet chamber 25. An inlet pipe 27 extends from the top 2 of the enclosure 1 through the chamber 25 and extends into the chamber 7a.
In use of the furnace shown in Figure 1 hot gas from a burner (not shown) is delivered into the passage 7 via the pipe 9. The gas passes through the gaps between the blades of the ring 21. A toroidal hot gas flow is thereby established near the ring 21 in the chamber 7a.
Material to be heat treated in the furnace is introduced via the inlet pipe 27 into the heating zone provided by the toroidal flow. The powdered product formed by this process is eventually transferred into the chamber 25 from the chamber 7a and is extracted by a cyclone (not shown) attached to the outlet pipe 28 where product solid material is separated from output gases.
In use of the furnace shown in Figure 1 for the calcining of kaolin powder at a temperature of above about 8000C, eg. at a temperature of 9500C, we found that unwanted deposits of material formed from the feed kaolin built up in various regions of the furnace, especially in the region labelled R1 shown in Figure 1. This problem has been solved as for region R1 as follows.
Figure 2 shows a furnace embodying the present invention for producing a fluid flow heating zone of the toroidal kind. In Figure 2 items which are similar to items in the furnace shown in Figure 1 have like reference numerals.
In Figure 2, the portion 13 has no bore and is supported by blocks 42, 43 which are stainless steel support rings provided between the support 17 and portion 13. A ring of fuel inlet tubes 45 (two only shown in Figure 2) is provided beneath the blocks 42, 43. The tubes 45 project upwardly at their inner ends into the chamber 7a above the ring 21. The tubes 45 are connected at a central joint 47 to which in turn is connected to a single inlet pipe 49 extending through the base 3, portion 6c and tubular support 11.
A series of inlet tubes 23 (one only shown) is provided. The tubes 23 are spaced circumferentially around the wall 4 and are fitted through the wall 4 and portion 5d to enter the chamber 7a.
In use of the furnace shown in Figure 2, hot reacting fluid, eg. hot air, is delivered into the passage 7 in the direction of the arrow X. The fluid passes through the gaps between blades of the ring 21 and thereby forms a toroidal flow above the ring 21. The fluid reacts with fuel delivered into the chamber 7a via the tubes 23 and forms a plasma flow by spontaneous reaction of the fuel with the reacting fluid flow. This causes the location in the chamber 7 at which heating zone in the toroidal flow is established to be elevated to a region clear of the narrow gap between the portion 5d and the base of the portion 13 and the blocks 42 and 43 thereby avoiding overheating of the blades of the ring 21 and the surfaces adjacent to the ring 21. Overheating of the ring 21 and adjacent surfaces is also avoided because the reacting fluid is delivered at a temperature, eg. 7500C to 8000C, considerably less than that , eg.
15000C to 16000C which may be required in some processes in the use of the furnace shown in Figure 1. Particulate material is injected via the inlet tubes 23 into the toroidal flow heating zone.
Significant overheating of the ring 21 and build up of solid material from the particulate material being treated in the furnace shown in Figure 2 in the region R1 (Figure 1) does not occur because of the differences in construction and operation applied in the case of Figure 2.
In use of the furnace shown in Figure 2 where the hot reacting fluid is air the air, delivered into the passage 7 in the direction of the arrow X, may be heated by burning fuel in a burner (not shown) and allowing the burning fuel and hot exhaust gases produced thereby to be combined with the air flow to be heated. The fuel used to preheat the air in this way may be the same as the fuel delivered into the chamber 7a via the tubes 23, eg.
natural gas.

Claims (8)

1. A furnace of the kind in which a toroidal fluid flow heating zone may be established, the furnace including a chamber in which there is provided an inner block, and a ring of angled blades between the inner block and the inner wall of the chamber, means for delivering fluid into the chamber whereby the fluid passes through gaps between the said blades and establishes a toroidal fluid flow heating zone in the chamber above the ring of angled blades and means for injecting into the chamber in the region where the toroidal fluid flow heating zone is to be established feed particulate material and characterised in that the furnace includes means for injecting fuel into the chamber in the region above the ring of angled blades whereby the region in the chamber at which the heating zone is established may be elevated above and beyond the ring of angled blades.
2. A furnace as claimed in claim 1 and wherein the said further means includes a ring of circumferentially spaced fuel inlet tubes.
3. A furnace as claimed in claim 2 and wherein the fuel inlet tubes are connected to a common joint or housing connected to a common fluid inlet delivery pipe.
4. A furnace as claimed in claim 2 or claim 3 and wherein the said inlet tubes project upwardly into the said chamber.
5. A furnace as in any one of the preceding claims and wherein the furnace includes a source of hot fluid which reacts with the fuel in the chamber.
6. A furnace as in claim 5 and wherein the said source includes a heater for heating a fluid before delivery to the said chamber.
7. A furnace as in claim 5 or claim 6 and wherein the said reacting fuel comprises hot air or oxygen and the said fuel comprises a combustible fuel for combustion in the chamber in the hot air or oxygen.
8. A furnace as claimed in claim 1 and substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.
GB9615418A 1996-07-23 1996-07-23 Furnaces Revoked GB2315431B (en)

Priority Applications (13)

Application Number Priority Date Filing Date Title
GB9615418A GB2315431B (en) 1996-07-23 1996-07-23 Furnaces
DE69706993T DE69706993T2 (en) 1996-07-23 1997-07-23 OVEN WITH A RING-SHAPED FLUID FLOW HEATING ZONE
AT97932948T ATE206071T1 (en) 1996-07-23 1997-07-23 OVEN WITH AN ANNUAL FLUID FLOW HEATING ZONE
DK97932948T DK0914201T3 (en) 1996-07-23 1997-07-23 Heat zone oven with annular fluid flow
JP50671998A JP4115533B2 (en) 1996-07-23 1997-07-23 A furnace having an annular fluid flow heating zone
ES97932948T ES2164360T3 (en) 1996-07-23 1997-07-23 OVEN THAT PRESENTS A HEATING AREA BY CIRCULATION OF TOROIDAL FLUID.
BR9710516-3A BR9710516A (en) 1996-07-23 1997-07-23 Furnace with heating zone for toroidal fluid flow.
AU36306/97A AU730499B2 (en) 1996-07-23 1997-07-23 Furnace having toroidal fluid flow heating zone
CA002261230A CA2261230C (en) 1996-07-23 1997-07-23 Furnace having toroidal fluid flow heating zone
PCT/GB1997/002000 WO1998003256A1 (en) 1996-07-23 1997-07-23 Furnace having toroidal fluid flow heating zone
PT97932948T PT914201E (en) 1996-07-23 1997-07-23 FURNACE WITH TOROIDAL FLUID FLOOR HEATING AREA
EP97932948A EP0914201B1 (en) 1996-07-23 1997-07-23 Furnace having toroidal fluid flow heating zone
US09/214,951 US6139313A (en) 1996-07-23 1997-07-23 Furnace having toroidal fluid flow heating zone

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9615418A GB2315431B (en) 1996-07-23 1996-07-23 Furnaces

Publications (3)

Publication Number Publication Date
GB9615418D0 GB9615418D0 (en) 1996-09-04
GB2315431A true GB2315431A (en) 1998-02-04
GB2315431B GB2315431B (en) 2000-03-29

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GB9615418A Revoked GB2315431B (en) 1996-07-23 1996-07-23 Furnaces

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CN109502596B (en) * 2018-12-29 2020-09-01 中国矿业大学 Method for preparing metakaolin from rapidly-descending flash calcined kaolin

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2203670A (en) * 1987-04-10 1988-10-26 Torftech Ltd Process on or with liquid
WO1994019122A1 (en) * 1993-02-24 1994-09-01 Great Eastern (Bermuda), Ltd. Process and apparatus for removal of petroleum from particulate materials
WO1995017982A1 (en) * 1993-12-24 1995-07-06 Torftech Limited Contaminant removal

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2203670A (en) * 1987-04-10 1988-10-26 Torftech Ltd Process on or with liquid
WO1994019122A1 (en) * 1993-02-24 1994-09-01 Great Eastern (Bermuda), Ltd. Process and apparatus for removal of petroleum from particulate materials
WO1995017982A1 (en) * 1993-12-24 1995-07-06 Torftech Limited Contaminant removal

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GB2315431B (en) 2000-03-29

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Legal Events

Date Code Title Description
730 Substitution of applicants allowed (sect. 30/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20020723

773K Patent revoked under sect. 73(2)/1977