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WO1987004780A1 - Procede de sechage d'un materiau pulverulent, granulaire ou en forme de copeaux ou d'un materiau analogue - Google Patents

Procede de sechage d'un materiau pulverulent, granulaire ou en forme de copeaux ou d'un materiau analogue Download PDF

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Publication number
WO1987004780A1
WO1987004780A1 PCT/FI1987/000017 FI8700017W WO8704780A1 WO 1987004780 A1 WO1987004780 A1 WO 1987004780A1 FI 8700017 W FI8700017 W FI 8700017W WO 8704780 A1 WO8704780 A1 WO 8704780A1
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WO
WIPO (PCT)
Prior art keywords
drying
dried
magnetic
magnetic material
mixture
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.)
Ceased
Application number
PCT/FI1987/000017
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English (en)
Inventor
Antero Jahkola
Markku Huhtinen
Tapani Peltola
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.)
VTT Technical Research Centre of Finland Ltd
Original Assignee
VTT Technical Research Centre of Finland 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 VTT Technical Research Centre of Finland Ltd filed Critical VTT Technical Research Centre of Finland Ltd
Publication of WO1987004780A1 publication Critical patent/WO1987004780A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
    • F26B3/06—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
    • F26B3/08—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed
    • F26B3/088—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed using inert thermally-stabilised particles

Definitions

  • the present invention concerns a method for the drying of a powdery, granular, chip-formed or equivalent material.
  • the drying method in accordance with the invention is suitable for use in the drying of, e.g., various solid fuels, such as peat, wood chips or shingles, and also of grain and of various powdery or granular products of food, fodder and chemical industries.
  • a method for the drying of solid fuels is prior known from the FI Patent 11200, wherein the drying of the material Containing water is performed regeneratively by mixing hot particles, which are heated in a heat source, e.g., in combustion gases, with the material to be dried.
  • the method involves that the particles, which function as heat carriers, are heated as hot as possible in order to keep the material flow of the particles, which function as heat carriers, reasonable. That is why the method is badly applicable to be used far drying organic materials which are sensitive to the action of heat.
  • This disadvantage can be eliminated by accomplishing the drier by means of the fluidized bed technics. The bed of even temperature is typical for the fluidized bed technics.
  • One drying method is described, e.g., in the FI Patent Application 832049, wherein the drying is performed by means of the fluidized bed principle.
  • the drying is carried cut in a particular drying plant, which consists of a container, through which pipes are passed, through which said pipes the flue gases coning from the boiler are passed.
  • a sand layer is fitted, which is heated by means of the flue gases passing through the said pipes.
  • the fuel to be dried is made to pass through the said bed material, whereby the moisture contained in the fuel is vaporized as the fuel passes through the heat sand layer.
  • the fuel is passed into a cyclone, wherein the water vapour is separated from the fuel, and hereinafter the fuel is fed into the boiler for combustion.
  • the object of the present invention is to provide a method for the drying of a powdery, granular, chip-formed or equivalent material which said method does not involve the above drawbacks of the prior-art methods.
  • the invention is mainly characterized in that the material to be dried is, at least for the time of the drying, mixed with a magnetic material and that the drying of the material to be dried cut in a mixture of the said material to be dried and of the said magnetic material by passing heat into the mixture of the said materials.
  • the separation of the material to be dried from the material in which the drying is performed becomes excellent, because a magnetic material is used as such a material.
  • the material to be dried can be separated from the other material, so-called bed material, by using, e.g., magnetic separators.
  • the method of the invention is very well suitable for use in cases in which no foreign matter is allowed to be present among the material dried. Since, owing to the above, the dried material can be separated from the bed material well, the consistency of the bed material may be very finely divided. This again results in the circumstance that the heat transfer factor between the bed material and the indirect heat exchanger has became very good.
  • the equipments in which the drying is performed as of small size Owing to the good heat transfer, it is again possible to construct the equipments in which the drying is performed as of small size. This again results in the circumstance that the investment costs of the equipments are considerably lower than those of equipments that make use of prior-art methods. Since a very finely divided material can be used as the magnetic material, the said finely divided material improves the fluidity of the material to be dried in the different parts of the dryer. Moreover, the magnetic material helps to keep the faces of the dryer clean.
  • Fig. 1 is a schematical illustration of the principle of a heatable fluidized bed dryer which can be used for accomplishing the method of the invention.
  • Fig. 2 is a schematical sectional view of a magnetic separator that can be used in the method of the invention.
  • Fig. 1 is a schematical illustration of the principle of operation of a fluidized bed dryer 10 operating by means of the method of the invention.
  • the main components of the equipment are a dryer container 11, in which the drying of the material to be dried is performed, a cyclone 20, in which the drying gas, e.g. superheated water vapour, is separated from the material to be dried, as well as a magnetic separator 30, which separates the dried material from the bed material.
  • the dryer container 11 of the fluidized bed dryer may be, e.g., a vertically positioned cylindrical vessel of the sort shown in Fig. 1.
  • a perforated grate 12 is mounted, an which a drying bed of a magnetic material A has been formed as a bed.
  • a magnetic bed material A a finely divided particle-like or sand-like material is used, e.g. magnetite, even though other magnetic materials are also suitable for use in the method in accordance with the invention.
  • a heat exchanger 14 is installed, in which a circulation of, e.g., pressurized water or steam is arranged, which said water os steam heats the magnetic bed material A as well as the material B to be dried.
  • a circulation of, e.g., pressurized water or steam is arranged, which said water os steam heats the magnetic bed material A as well as the material B to be dried.
  • a feed connection or equivalent 15 is formed, through which the material B to be dried is fed to underneath the bed material A, above the grate 12.
  • the feed duct 15 may preferably be provided, e.g., with a screw-type feeder, by means of which the material B to be dried can be fed into the magnetic bed material A.
  • a feed pipe 19 is farmed, through which the drying gas C used in the drying of the material is fed into the dryer container 11, to underneath the material B to be
  • a first exhaust pipe 16 is formed, through which the drying gas C passing through the dryer container 11 and, along with it, a slight quantity of the dried material B' and of the magnetic bed material A are removed out of the dryer container 11 into the cyclone 20.
  • a second exhaust pipe 18 is formed further, which is arranged in the dryer container 11 at such a level that the mixture of the bed material A and the material B to be dried covers the mouth of the said second exhaust pipe 18.
  • the second exhaust pipe 18 is provided, e.g., with a screw conveyor or equivalent, by means of which mixture of the magnetic bed material A and of the dried material B' is removed out of the dryer container 11.
  • part of the dried material B' is carried along with the drying gas C out of the dryer container 11 along the first exhaust pipe 16 into the cyclone 20.
  • the solid materials are separated from the drying gas, whereinafter the said solid materials are passed cut of the cyclone 20 along an exhaust duct 21 for solid materials into a magnetic separator 30.
  • the drying gas C is again passed out of the cyclone 20 along an exhaust duct 22 into a circulation duct 24, from which it is fed, e.g., by means of a blower 25 fr ⁇ a the feed pipe 19 again into the dryer container 11.
  • Fig. 1 only one cyclone 20 is shown, but in practice it may be advantageous to provide several cyclones 20 one after the other, in which case the drying gas and the solid materials can be separated froa each other better.
  • mixture of the magnetic bed material A and of the dried material B' is removed cut of the dryer container 11 from the top of the bed through the second exhaust pipe 18, e.g., by means of a screw conveyor, being passed into the magnetic separator 30.
  • the said second exhaust pipe 18 may be connected to the outlet duct 21 for solids after the cyclone 20, e.g., as is shown in Fig. 1.
  • superheated water vapour can be used as the drying gas C instead of the commonly used drying gas, air.
  • the superheated water vapour is obtained to the system in connection with the drying out of the dried material B.
  • Superheated water vapour is in many respects preferable to air. Firstly, if air is used as the drying gas in the drying, the system becomes highly sensitive to fire if the dried material is readily inflammable. When superheated water vapour is used as the drying gas, the energy consumption of the drying process can be reduced essentially, e.g., by condensing the liberated heat for heating purposes.
  • the dryer by constructing the dryer so that it comprises several stages, whereat a different pressure is used in each stage, it is possible to use the water vapour liberated from a dryer operating at a higher pressure far heating a dryer operating at a lower pressure. Moreover, in a single-stage dryer, the liberated water vapour can be compressed to a higher pressure and be used for heating the dryer itself.
  • the mixture of the magnetic bed material A and of the dried material B' is passed along the feed duct 31 into the magnetic separator 30.
  • the construction and operation of the magnetic separator 30 are examined in more detail in Fig. 2.
  • the magnetic separator 30 is provided with separate cutlet ducts 32 and 33 far the dried material B' and far the magnetic bed material A.
  • the magnetic bed material A is passed from the magnetic separator along the outlet duct 33 back into the system into the dryer container 11.
  • the bed material A may be passed into the dryer container 11 through the top portion, as is denoted with reference numeral 33, or the bed material may be passed into the feed duct 15 for the material to be dried, as is shown by reference numeral 33A and by broken lines.
  • Fig. 1 shows schematically that there is only one magnetic separator 30 in the system. In order to improve the degree of separation, the system may, however, be provided with several magnetic separators placed one after the other. In preliminary separation tests, the dried material B' coming cut of the fluidized bed dryer 10 contained 25 % of magnetic bed material A before the magnetic separator 30, and only 2 % after the magnetic separator 30.
  • Fig. 2 is a schematical sectional view of a magnetic separator 30 which can be used in the method of the invention.
  • the magnetic separator 30 comprises a substantially cylindrical mantle 36, into which a feed duct 31 has been formed for the mixture of the magnetic material A and the dried material B'. as well as outlet ducts 32 and 33 for the dried material B' and the magnetic materials A.
  • a metal cylinder 34 is mounted as revolving, so that a space of a certain magnitude remains between the outer face of the metal cylinder 34 and the inner face of the mantle 36.
  • a magnet 35 is provided in accordance with Fig. 2, which said magnet 35 extends in accordance with Fig. 2 in the direction of the circumference of the metal cylinder 34, beginning from the feed duct 34, beyond both of the outlet ducts 32 and 33.
  • the magnetic material A adheres to the face of the metal cylinder 34 by the effect of the magnet 35, whereas the dried material B runs in the space between the metal cylinder 34 and the mantle 36 of the magnetic separator freely.
  • the outlet ducts 32 and 33 are arranged in the mantle 36 so that the outlet duct 32 far the dried material B' is placed before the outlet duct 32 for the dried material B' is placed before the outlet duct 32 for the magnetic material A, in the direction of rotation of the metal cylinder 34.
  • the dried material B' can run out of the said outlet duct, whereas the magnetic material A runs, adhering to the metal cylinder 34 by the effect of the magnet 35. beyond the cutlet duct 32 for the dried material and is detached from the metal cylinder 34 only after it has by-passed the area of effect of the magnet 35, being thereupon removed out of the magnetic separator 30 through the outlet duct 33 for the magnetic material.
  • the construction of the magnetic separator 30 may also be different from that shown in Fig. 2, for the embodiment shown in the figure is just supposed to illustrate the invention.
  • a magnetic material and a magnetic separator for example as compared with the prior-art fluidized bed dryers, the remarkable advantage is obtained that a considerably more finely divided material can be used as the bed material than in prior art.
  • it has been necessary to keep the particle size at a level of about 1 mm whereas in the method of the present invention it is possible to use a bed material whose particle size is, e.g., 0.20 to 0.50 mm. Thereby the heat transfer factor between the bed material and the indirect heat exchanger in the dryer becomes considerably better than in the prior-art methods.
  • the invention has been described with reference to the figures in the attached drawing.
  • the method of the invention is, however, not supposed to be confined to the embodiments shown in the figures alone.
  • the material B to be dried is mixed with a magnetic material A and that the drying of the material B to be dried is performed in a mixture of the materials A and B.
  • the magnetism it is an essential feature of the invention that, after drying, the materials are separated from each other and the magnetic material separated fromthe mixture is returned to the dryer used in the method.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)

Abstract

Le procédé ci-décrit consiste à mélanger, du moins pendant le temps de séchage, le matériau (B) devant être séché avec un matériau magnétique (A), le séchage du matériau (B) devant être séché s'effectuant dans un mélange dudit matériau (B) et du matériau magnétique (A) en soumettant le mélange desdits matériaux (A) et (B) à un traitement à la chaleur. Après le séchage, le matériau magnétique (A) et le matériau séché (B') sont séparés l'un de l'autre, le matériau séché (B') étant acheminé sur son lieu d'utilisation et le matériau magnétique (A) étant remis en circulation dans le mélange du matériau (B) devant être séché et du matériau magnétique (A). Le procédé de séchage utilisé est le séchage en lit fluidisé, qui permet au mélange du matériau (B) devant être séché et du matériau magnétique (A) d'être fluidisé à l'aide du gaz de séchage (C). De la vapeur d'eau surchauffée est utilisée avantageusement comme gaz de séchage (C).
PCT/FI1987/000017 1986-01-31 1987-01-29 Procede de sechage d'un materiau pulverulent, granulaire ou en forme de copeaux ou d'un materiau analogue Ceased WO1987004780A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI860468 1986-01-31
FI860468A FI79753C (fi) 1986-01-31 1986-01-31 Foerfarande foer torkning av pulverformigt, kornigt, spaonformigt eller motsvarande material.

Publications (1)

Publication Number Publication Date
WO1987004780A1 true WO1987004780A1 (fr) 1987-08-13

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ID=8522077

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1987/000017 Ceased WO1987004780A1 (fr) 1986-01-31 1987-01-29 Procede de sechage d'un materiau pulverulent, granulaire ou en forme de copeaux ou d'un materiau analogue

Country Status (2)

Country Link
FI (1) FI79753C (fr)
WO (1) WO1987004780A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0379657A1 (fr) * 1989-01-27 1990-08-01 Sulzer-Escher Wyss Gmbh Procédé de séchage de boues
GB2259694A (en) * 1991-09-18 1993-03-24 Shell Int Research Method and apparatus for powdered solids pressurization
RU2156932C1 (ru) * 1999-05-17 2000-09-27 Северо-Кавказский государственный технологический университет Вибросушилка
WO2010052405A3 (fr) * 2008-11-04 2011-01-13 Jean-Xavier Morin Dispositif de sechage de biomasse solide et utilisation de ce dispositif
RU2571065C1 (ru) * 2014-10-17 2015-12-20 Открытое акционерное общество "Научно-исследовательский институт металлургической теплотехники" (ОАО "ВНИИМТ") Способ сушки пылящих мелкозернистых материалов и установка для его осуществления (варианты)
RU2571877C1 (ru) * 2014-09-05 2015-12-27 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Тамбовский государственный технический университет" ФГБОУ ВПО ТГТУ Установка для сушки дисперсных растительных материалов в полидисперсном слое инертных тел
CN109140905A (zh) * 2018-07-25 2019-01-04 北京富海天环保科技有限公司 一种振动流化床干燥装置及干燥方法
RU2679994C1 (ru) * 2018-03-06 2019-02-14 Федеральное государственное бюджетное образовательное учреждение высшего образования "Тамбовский государственный технический университет" (ФГБОУ ВО "ТГТУ") Установка для сушки пастообразных материалов в закрученном взвешенном слое инертных тел

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2094183A (en) * 1981-02-24 1982-09-15 Cryogenic Consult Magnetic separator for dry material
US4349967A (en) * 1980-10-06 1982-09-21 General Electric Company Magnetic field coupled spouted bed system
GB2105617A (en) * 1981-07-06 1983-03-30 Foskem Pty Limited Magnetic separation
US4463502A (en) * 1982-03-08 1984-08-07 Fitzgerald Thomas J Magnetic distributor-downcomer for fluidized beds and magnetic valve to control the flow of solids

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4349967A (en) * 1980-10-06 1982-09-21 General Electric Company Magnetic field coupled spouted bed system
GB2094183A (en) * 1981-02-24 1982-09-15 Cryogenic Consult Magnetic separator for dry material
GB2105617A (en) * 1981-07-06 1983-03-30 Foskem Pty Limited Magnetic separation
US4463502A (en) * 1982-03-08 1984-08-07 Fitzgerald Thomas J Magnetic distributor-downcomer for fluidized beds and magnetic valve to control the flow of solids

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0379657A1 (fr) * 1989-01-27 1990-08-01 Sulzer-Escher Wyss Gmbh Procédé de séchage de boues
GB2259694A (en) * 1991-09-18 1993-03-24 Shell Int Research Method and apparatus for powdered solids pressurization
RU2156932C1 (ru) * 1999-05-17 2000-09-27 Северо-Кавказский государственный технологический университет Вибросушилка
WO2010052405A3 (fr) * 2008-11-04 2011-01-13 Jean-Xavier Morin Dispositif de sechage de biomasse solide et utilisation de ce dispositif
RU2571877C1 (ru) * 2014-09-05 2015-12-27 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Тамбовский государственный технический университет" ФГБОУ ВПО ТГТУ Установка для сушки дисперсных растительных материалов в полидисперсном слое инертных тел
RU2571065C1 (ru) * 2014-10-17 2015-12-20 Открытое акционерное общество "Научно-исследовательский институт металлургической теплотехники" (ОАО "ВНИИМТ") Способ сушки пылящих мелкозернистых материалов и установка для его осуществления (варианты)
RU2679994C1 (ru) * 2018-03-06 2019-02-14 Федеральное государственное бюджетное образовательное учреждение высшего образования "Тамбовский государственный технический университет" (ФГБОУ ВО "ТГТУ") Установка для сушки пастообразных материалов в закрученном взвешенном слое инертных тел
CN109140905A (zh) * 2018-07-25 2019-01-04 北京富海天环保科技有限公司 一种振动流化床干燥装置及干燥方法
CN109140905B (zh) * 2018-07-25 2020-08-21 北京富海天环保科技有限公司 一种振动流化床干燥装置及干燥方法

Also Published As

Publication number Publication date
FI860468A7 (fi) 1987-08-01
FI79753B (fi) 1989-10-31
FI860468A0 (fi) 1986-01-31
FI79753C (fi) 1990-02-12

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