WO1991006105A1 - Appareils a calciner du type a vibrations - Google Patents

Appareils a calciner du type a vibrations Download PDF

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Publication number
WO1991006105A1
WO1991006105A1 PCT/AU1990/000498 AU9000498W WO9106105A1 WO 1991006105 A1 WO1991006105 A1 WO 1991006105A1 AU 9000498 W AU9000498 W AU 9000498W WO 9106105 A1 WO9106105 A1 WO 9106105A1
Authority
WO
WIPO (PCT)
Prior art keywords
duct
particulate material
calcining
tubular
inlet
Prior art date
Application number
PCT/AU1990/000498
Other languages
English (en)
Inventor
Eric John Ramm
Original Assignee
Australian Nuclear Science & Technology Organisation
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 Australian Nuclear Science & Technology Organisation filed Critical Australian Nuclear Science & Technology Organisation
Priority to AU65459/90A priority Critical patent/AU649968B2/en
Publication of WO1991006105A1 publication Critical patent/WO1991006105A1/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
    • B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis
    • B01J6/001—Calcining
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/28—Treating solids
    • G21F9/30—Processing
    • G21F9/32—Processing by incineration

Definitions

  • the present invention relates to vibratory calciners. Calcination is a process in which particulate material is subjected to elevated temperature to remove volatiles and to achieve a reactive powder product.
  • the present invention will illustrated by application to a particularly demanding application in the calcination field, namely the calcinat of synthetic rock precursor loaded with nuclear waste material which is to be immobilised in the final syntheti rock.
  • the most stringent protective measures and safety precautions must be taken.
  • the equipment must h an inherent design which permits it to operate with at mo simple maintenance to be conducted only with manipulators and a very long working life is needed.
  • a relatively compact structure is desirable in view of the very high cost of building an active cell which is a safe containment structure for handling radioactive materials.
  • the present invention can be especially useful in providing major advances and advantages for disposal of high level radioactive waste i synthetic rock but the invention is not limited to these applications and the apparatus and methods described here can advantageously be applied to analogous manufacturing methods and equipment design.
  • the present invention broadly provides an apparatu for calcining particulate material, the apparatus comprising (a) a calcining structure defining a path between first and second vertically spaced locations, (b) means for introducing the particulate material at the first location, (c) means for discharging calcined particulate material at the second location, (d) heating means for establishing a calcining temperature along at least part of the path for calcining the particulate material, (e) vibrator means for vibrating the calcining structure to cause advance of the particulate material along the path, (f) the calcining structure being closed for providing a controlled environment along the path and (g) the calcining structure providing ramp means inclined at a shallow angle to the horizontal and extending along the path for supporting the particulate material and being generally serpentine such that the path length is relatively large compared with the distance between the first and second locations in the vertical direction and composed with the dimensions of the calcining structure in a horizontal direction.
  • the ramp means comprises series of separate ramp elements partially overlapping one another and providing a zig-zag path down which the particulate material is adapted to be moved under operatio of the vibrator means;
  • the ramp means is a generally spiral tubular processing duct and in this case the vibrator means can be a means to move the particulate material upwardly through the duct.
  • the calcining structure in horizontal cross-section can be generally rectangular with the ramp elements rigidly connected to th side walls, each ramp element extending from one side wall and terminating just short of the opposite side wall.
  • the vibrator means preferably comprises a primary vibrator connected to a central base portion of the calcining structure and adjacent a lower discharge duct, in addition an intermittent pulse vibrator is advantageo added to ensure reliable control of the process and stea advance of the particulate material.
  • the apparatus preferably includes at opposite end inlet and outlet connections to a supply of gas for providing a controlled atmosphere within the calcining structure.
  • a counter-current flow of a mixture o hydrogen and nitrogen is desirably utilised, the mixture typically comprising 3.5% hydrogen.
  • the vibrator means comprises a vibrat unit mounted to vibrate a base portion of the calcining structure.
  • the vibration mode typically has a frequency about fifteen hundred cycles per minute with an amplitud about three millimetres with a lift and twist motion.
  • an apparatus calcining particulate material comprising support structure in the form of a generally spiral tubu processing duct, means for mounting the duct with the ax around which the duct extends being a vertical axis, an inlet at one end of the duct adapted to be connected to means for supplying the particulate material and an outl at the opposite end of the duct for discharging the calc material, vibrator means for vibrating the duct in a mod cause an advancement of the particulate material from th inlet to the outlet and heating means for establishing a calcining temperature in the tubular duct for calcining particulate material.
  • the tubular duct may be wound helically with the inlet located at the bottom end and the outlet extending from the upper end of the helical shape, the tubular duct being closed and having means for connection to atmosphere control means whereby the calcination can take place under a controlled atmosphere.
  • the form of the tubular duct can be varied to suit the application but it has been found especially beneficial to provide a generally rectangular cross-sectional shape.
  • the tubular duct has contiguous turn which abut and support one another and the bottom face of the tubular duct is supported by resting on a multiplicity of spaced support elements which are rigidly connected to the base plate.
  • the apparatus preferably includes a discharge duct extending from the outlet of the tubular du to a location below tubular duct for discharging the particulate material into a collection hopper.
  • the apparatus includes a supply hopper arranged at a higher elevation than the inlet to the tubular duct a having a feed device to supply the particulate material progressively to the tubular duct.
  • a screw fee device is provided and flexible tubular couplings connect the screw feed device to the inlet to the tubular duct and connect the outlet of the tubular duct to the discharge du which leads to the collection hopper.
  • the heating means can be of any suitable form but preferably is arranged as a furnace structure extending around the vertical axis of the support structure; for example the furnace heating elements can be arranged in a cylindrical form and an insulation structure is provided above and below the support structure.
  • temperature and corrosion resistant metal alloys are used with advantage for the calcining structure.
  • the calcining of synthetic rock components can be conducted to a temperatu of about 850°C and at these temperatures alloys such as Sandvik 253MA or Inconel 601 materials can be used.
  • alloys such as Sandvik 253MA or Inconel 601 materials
  • other embodiments of the invention may be applicable to even higher temperature calcination and for that purpose the duct is to be fabricated from materials resistant to higher temperatures.
  • very high temperature metal alloys or ceramic materials could be considered where calcining temperatures of the order of 1500°C are required.
  • a counter current gas flo can be provided by providing means for connecting a select gas supply to the outlet from the tubular duct and a gas discharge system connected at the region of the inlet to t tubular duct whereby counter current gas flow may be provided.
  • a most beneficial arrangement is one which a mixture of hydrogen and nitrogen as a reducing gas is supplied into the collection hopper and this flows in counter current through the processing duct.
  • preferably two off-gas pipes are connected to an inlet pipe which leads into the inlet to the tubular spiral processing duct and arranged such that a first pipe removes water vapour resulting from the decomposition that takes place in the calcining step and oxides of nitrogen are discharged into second pipe.
  • a further inlet for nitrogen gas is provided between the connection point to the device for supplying the particulat material and the inlet end of the spiral tubular duct. For example nitrogen gas is supplied to pressurize this portion of the system.
  • a method of calcining a particulate material comprising using apparatus as described above in any one of the embodiments indicated.
  • the method is especially advantageous when applied to the difficult problem of calcining synthetic rock precursor which incorporates high level radioactive waste.
  • a controlled atmosphere must be provided with an off-gas processing system to deal with radioactive volatile components release in a small quantity during the calcination and in particula it is necessary to deal with cesium, ruthenium and molybdenum.
  • the apparatus is intrinsically simple with few parts liable to require maintenance and a long working lif measured in many years should be achievable;
  • a very high throughput rate is achievable while simultaneously producing a very desirable particle structu in the resultant material; the particulate material advanc at a highly uniform rate along the duct and a residence ti as short as about 2 minutes can be achieved while providin full calcination reliably and achieving an excellent particle structure.
  • a granulated type structure which does not cake or have fine dust particles an unacceptable quantity and which can readily be poured subsequent processing steps is achievable.
  • a controlled atmosphere can provided in embodiments of the invention without using an mechanical sliding seals such as would be required in a rotary calciner and this aids minimum maintenance requirements;
  • the equipment can be designed such that when components of the apparatus wear out replacement is quite feasible in an active cell.
  • Figure 1 is a schematic elevation of a first embodiment utilising a continuous spiral ramp
  • Figure 2 is a second embodiment using a downwardly directed zigzag ramp structure; and Figure 3 is a schematic plan view of the embodiment of figure 2.
  • Both of the illustrated embodiments are particularly adapted for use in a radiation cell and for calcining synthetic rock components incorporating high level radioactive waste.
  • the apparatus comprises a helical tubular vibrating duct 10 disposed about a vertical axis and arranged for conveying and calcining particulate material as it moves upwardly along the interio ramp-like surface of the duct.
  • the duct has an inlet portion 11 lowermost and an outlet portion 12 uppermost and is surrounded by a furnace 13 with insulation material not shown in the drawing for providing thermal efficiency.
  • the desired temperature gradient is established along the duct which defines the processing path in accordance with the material to be calcined.
  • the helical duct comprises a multiplicity of turns 9 of a substantially cylindrical cross-section metal alloy duct, the turns being in abutment one on top of the other and providing a shallow ramp, and the lowermost turn is supported by a series of spaced support feet 14 which are rigidly interconnected to a base plate 15 which is mounted through a series of circumferentially spaced spring mounts 16 to support the tubular duct on a support frame 17.
  • An insulation layer 18 overlays the base plate and is disposed beneath the tubular duct.
  • the base plate is connected to motorised vibrators 19 which typically vibrates the base plate at a frequency of around fifteen hundred cycles per minute and with an amplitude of around three millimetres. It has been found this will cause particulate material t vibrated within the duct and to move progressively up th shallow ramp-like surface of the helical duct.
  • the inlet portion 11 to the duct incorporates a connection 20 to a source of nitrogen gas and has a flex coupling 21 connecting the inlet portion to the discharg from a screw feeder 22 introducing the particulate mater progressively from a supply hopper 23.
  • the screw feeder packs the supply material tightly and sufficiently to effectively provide a gas seal and the nitrogen gas pres at the inlet prevents the escape of volatile products resulting from the calcination process.
  • a controlled atmosphere is provided in counter current flow within th helical duct 10.
  • the gases are discharged through first second discharge tubes 24 and 25 which connect to the in portion at spaced locations and respectively are positio for discharging water vapour and oxides of nitrogen to a off-gas system from which radioactive materials can be recovered.
  • the discharge portion 12 of the helical duct is connected to a discharge pipe 26 which. leads downwardly through the base plate 15 to a flexible coupling 27 to a fixed outlet pipe 28 from which the calcined material is discharged into a collection hopper 29 which is sealed.
  • collection hopper 29 has a gas inlet connection 30 for connection to a reducing gas supply whereby this gas move in counter current relationship through the apparatus.
  • the calciner comprises a rectangular cross-section vertical tubular du 40 surrounded by a furnace 41 with insulation surrounding the furnace and extending to top and bottom insulating en walls 42 and 43.
  • a multitude of ramp plates 44 arranged in an overlapping zigzag configuration and rigidly attached respectively to the side walls and one of the end walls of the duct.
  • the duct 44 tapers to a tubular discharge duct 45 aroun which an inclined angular wall 46 is provided and through which the duct is mounted by support springs 47.
  • the discharge duct 40 terminates with a flexible coupling 48 which in turn connects to an outlet pipe 49 for the calcine particulate material.
  • a primary vibrator 50 is mounted above the flexible coupling 48 for providing the desired normal vibrations to the support structure for advancing th particulate material.
  • a second vibrator 51 is also provide and adapted to be operated intermittently in a pulse mode t provide greater vibrations when required.
  • the upper end of the duct 40 is connected to an inle duct 52 which is coupled through a flexible connector 53 to an inlet pipe 54 leading from a supply of the particulate material.
  • a gas inlet duct 55 is provided at the bottom of the duct 40 and connected to a suitable source of a mixture of hydrogen and nitrogen typically comprises 3.5% hydrogen.
  • a gas discharge duct 56 is provide and this couples through a flexible connector 57 to an off gas pipe 58.
  • the gas discharge duct 56 and the particulate material inlet pipe 54 are supported at the upper end of th apparatus by a spring structure 59.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Thermal Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

Abstract

Un matériau particulaire, tel qu'un précurseur de roche synthétique imprégné de déchets radioactifs, est calciné dans un appareil à calciner vertical du type à vibrations, qui comprend une structure de conduite fermée (10 ou 40), une entrée (11 ou 52), une sortie verticalement espacée (12 ou 49), un four (13 ou 41) entourant la structure de conduite, ainsi qu'un organe vibratoire (19 ou 50 et 51) servant à imprimer des vibrations à la conduite de façon à faire avancer le matériau particulaire. La structure de conduite forme une rampe peu inclinée (9 ou 44) s'étendant en serpentin de façon à assurer un trajet de traitement à travers le four relativement long par rapport à la hauteur et aux dimensions horizontales de la structure de conduite.
PCT/AU1990/000498 1989-10-20 1990-10-18 Appareils a calciner du type a vibrations WO1991006105A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU65459/90A AU649968B2 (en) 1989-10-20 1990-10-18 Vibratory calciner

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPJ6970 1989-10-20
AUPJ697089 1989-10-20

Publications (1)

Publication Number Publication Date
WO1991006105A1 true WO1991006105A1 (fr) 1991-05-02

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1990/000498 WO1991006105A1 (fr) 1989-10-20 1990-10-18 Appareils a calciner du type a vibrations

Country Status (1)

Country Link
WO (1) WO1991006105A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5283058A (en) * 1990-08-30 1994-02-01 The General Hospital Corporation Methods for inhibiting rejection of transplanted tissue
WO2018152232A1 (fr) * 2017-02-14 2018-08-23 GeoRoc International, Inc. Procédés de traitement thermique

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4094630A (en) * 1976-09-08 1978-06-13 Combustion Engineering, Inc. Welding flux curing apparatus
US4237622A (en) * 1978-12-29 1980-12-09 Francis Theodore R Dryer using vibratory feeding
SU817085A1 (ru) * 1979-05-07 1981-03-30 Всесоюзный Научно-Исследовательскийи Проектный Институт Вторичной Цветнойметаллургии Устройство дл извлечени выплавл емогоМЕТАллА из пОдОВыХ шлАКОВ
SU877272A1 (ru) * 1978-06-22 1981-10-30 Предприятие П/Я М-5703 Вибрационна сушилка
GB2157408A (en) * 1984-04-10 1985-10-23 British Nuclear Fuels Plc Drying apparatus
US4778626A (en) * 1985-11-04 1988-10-18 Australian Nat'l Univ. of Acton Preparation of particulate radioactive waste mixtures
US4786249A (en) * 1986-11-11 1988-11-22 Kabushiki Kaisha Asada Spring heat treating furnace
US4806279A (en) * 1985-11-29 1989-02-21 Australian Atomic Energy Commission Method of producing impregnated synthetic rock precursor
FR2634187A1 (fr) * 1988-07-12 1990-01-19 Gradient Rech Royallieu Transporteur vibrant

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4094630A (en) * 1976-09-08 1978-06-13 Combustion Engineering, Inc. Welding flux curing apparatus
SU877272A1 (ru) * 1978-06-22 1981-10-30 Предприятие П/Я М-5703 Вибрационна сушилка
US4237622A (en) * 1978-12-29 1980-12-09 Francis Theodore R Dryer using vibratory feeding
SU817085A1 (ru) * 1979-05-07 1981-03-30 Всесоюзный Научно-Исследовательскийи Проектный Институт Вторичной Цветнойметаллургии Устройство дл извлечени выплавл емогоМЕТАллА из пОдОВыХ шлАКОВ
GB2157408A (en) * 1984-04-10 1985-10-23 British Nuclear Fuels Plc Drying apparatus
US4778626A (en) * 1985-11-04 1988-10-18 Australian Nat'l Univ. of Acton Preparation of particulate radioactive waste mixtures
US4806279A (en) * 1985-11-29 1989-02-21 Australian Atomic Energy Commission Method of producing impregnated synthetic rock precursor
US4786249A (en) * 1986-11-11 1988-11-22 Kabushiki Kaisha Asada Spring heat treating furnace
FR2634187A1 (fr) * 1988-07-12 1990-01-19 Gradient Rech Royallieu Transporteur vibrant

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DERWENT ABSTRACT, Accession No. 01544 E/01, Class M25; & SU,A,817 085, (VNIOPVTORTSVETMET), 5 April 1981. *
DERWENT ABSTRACT, Accession No. 74226, E/35, Class J08; & SU,A,877 272, (BUDRIK), 30 October 1981. *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5283058A (en) * 1990-08-30 1994-02-01 The General Hospital Corporation Methods for inhibiting rejection of transplanted tissue
WO2018152232A1 (fr) * 2017-02-14 2018-08-23 GeoRoc International, Inc. Procédés de traitement thermique
CN110267735A (zh) * 2017-02-14 2019-09-20 乔罗克国际股份有限公司 热处理方法
JP2020508429A (ja) * 2017-02-14 2020-03-19 ジオロック インターナショナル， インコーポレイテッド 熱処理の方法

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