US3544089A - Pneumatic elevators for lifting granular solids - Google Patents

Pneumatic elevators for lifting granular solids Download PDF

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Publication number
US3544089A
US3544089A US741743A US3544089DA US3544089A US 3544089 A US3544089 A US 3544089A US 741743 A US741743 A US 741743A US 3544089D A US3544089D A US 3544089DA US 3544089 A US3544089 A US 3544089A
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gas
gases
granular solids
receptacle
granular
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US741743A
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English (en)
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Pierre Ledent
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    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/10—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers
    • F26B17/101—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers the drying enclosure having the shape of one or a plurality of shafts or ducts, e.g. with substantially straight and vertical axis

Definitions

  • Kollin ABSTRACT Apparatus for the pneumatic elevation of granular solid products utilising a compressed carrier gas, comprising a closed receptacle the bottom of which is constituted by a porous surface, through which a gas may be blown at such a speed as to fluidize a bed of granular solids situated in said receptacle when the apparatus is in use, and a vertical elevator tube passing through the top wall of said receptacle and extending inside it, wherein means are provided for introducing a flow of high-temperature gas into said receptacle outside the elevator tube.
  • Such installations may function below atmospheric pressure but in that case the solid gas ratio is very low and the installation must comprise large fans and vast filtering devices for refining the carrier gas.
  • One way also have recourse to a compressed carrier gas but there is then the problem of introducing the solid into the said carrier gas; this problem is solved by relatively complicated mechanical devices, such as sieves, screws or honeycombed sluices.
  • An apparatus for the pneumatic elevation of granular solid products utilizing a compressed carrier gas and previously imagined by the applicant, comprises two receptacles communicating with one another at their lower part, the bottom of the said two receptacles being constituted by a porous surface, through which a gas may be blown at such a speed as to fluidize two intercommunicating beds of granular solids situated in the two receptacles when the apparatus is in u'se, in which the first receptacle acting as a feeding device is open at its upper part so that it may contain fluidized bed, the surface of which is at atmospheric pressure, and the second receptacle is a closed receptacle through the roof of which pass one or more vertical tubes capable of acting as a pneumatic elevator.
  • This apparatus can be employed simultaneously as a pneumatic elevator and as a heat exchanger in which heatexchange takes place between the carrier gas and the granular solids.
  • the gas is introduced through the porous surface acting as the base of the fluidized bed, the temperature at which the gas can be introduced is limited to the temperature which can be tolerated by the material of which said porous surface is composed.
  • the apparatus of the present invention enables this dra back to be overcome and is characterized by the fact that the quantity of gas introduced through the porous surface acting as the base of the fluidized bed is limited to the absolute minimum which is necessary to ensure fluidization of the granular solids, and that another flow of gas at a higher temperature is introduced above the level of the fluidized bed.
  • the total gas flow rises up through the vertical elevator tube or stack, which acts as a heat exchange by creating direct contact between the hot gases and the granular solids.
  • the effective cross section of the vertical elevator tube is generally so selected that the speed of circulation of the rising gases does not exceed a level of between 10 and 15 meters per second. This limitation on the speed of circulation increases the time during which the solids and the gases are in contact and this, of course, promotes heat transfer. Moreover, it also reduces the power consumption of and the rate of wear in the installation.
  • an elevator tube of very large diameter which will result in a reduction in the amount of heat transfer between the gas flowing up the tube and the granular solids, the latter preferably following a boundary layer close to the tube wall.
  • an elevator stack comprising two or more concentric tubes, the central tube being sealed at .at least the lower end thereof and the annular space or spaces between the said tubes being the only space utilized for the circulation of the gases and solids.
  • the temperature of the gas leaving the tube is always slightly higher than the temperature of the solids.
  • a waste-heat recovery system which can be used for air heating purposes and possibly to heat the gas which is used for the heating function and for the fluidization.
  • FIG. 1 is a diagrammatic sectional view of one embodiment of the apparatus of the present invention.
  • H6. 2 is a section along line ll-ll of H6. 1.
  • the apparatus illustrated comprises an assembly of two associated receptacles l and 2 communicating with one another at their lower parts through an opening 3.
  • the bases of these receptacles are in each case constituted by a porous surface 4 which may be a porous slab or any other appropriate kind of diffuser arrangement such as a perforated plate or grid of refractory steel. 7
  • the receptacle 2 all the internal walls of which are lined with a refractory material, communicates with a burner 5 which produces high-temperature gases; these gases are in troduced into the receptacle 2 above the surface of the fluidized bed and are evacuated through the elevator tube 6 which also acts as a heat exchanger between the gases and the granular product.
  • the elevator device comprises two concentric tubes of which the central one 7, sealed at its bottom end, the annular space between the two tubes being the sole space employed for the circulation of the gases and the solid materi-' als.
  • the gases and the solids are separated in chamber 8.
  • the granular solid material is evacuated across a screen and the gases are discharged through a flue after having passed through a heat exchanger 9 which preheats the air, compressed by the fan 10, used to produce the hot gases and to fluidize the bed of solid granular material contained in the receptacles l and 2.
  • An installation of this kind enables a granular solid to be heated to temperatures in the order of 800 C. with an overall thermal efficiency of as much as 80 percent.
  • the power consumed in lifting the granulated solids is very low as a result of the fact that the air compression takes place at ambient temperature but the air used for the lifting is at high temperature.
  • the power taken by the fan increases by only I kw. for an increase in sand throughput from 20 to 40 metric tons per hour.
  • the heating function residual gases (stack gases, exhaust gases etc. the pressure of which is insufficient to permit operation of the installation in the manner described.
  • the device is supplemented by the fan 11 located beyond the exchanger 9, in order to produce a forced draught in the system.
  • an apparatus for the pneumatic elevation of granular solid products utilizing a compressed carrier gas comprising' a closed receptacle the bottom of which is constituted by a porous surface, through which a gas may be blown at such a speed as to fluidize a bed of granular solids situated in said receptacle when the apparatus is in use, and a vertical elevator tube passing through the top wall of said receptacle and ex-;
  • said means for introducing the flow of high-temperature gas comprise one or more gas burners or oil burners located in a vertical wall of said receptacle.
  • said elevator tube comprises at least two concentric tubes, the centre one of said tubes being sealed at at least its lower end.
  • said elevator tube comprises two concentric tubes only.

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  • 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)
  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Polyesters Or Polycarbonates (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
US741743A 1967-07-12 1968-07-01 Pneumatic elevators for lifting granular solids Expired - Lifetime US3544089A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
BE701295 1967-07-12

Publications (1)

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US3544089A true US3544089A (en) 1970-12-01

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US741743A Expired - Lifetime US3544089A (en) 1967-07-12 1968-07-01 Pneumatic elevators for lifting granular solids

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US (1) US3544089A (de)
BE (1) BE701295A (de)
GB (1) GB1243210A (de)
NL (1) NL6809158A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3856459A (en) * 1972-07-27 1974-12-24 Canterbury Precision Engineers Heaters
FR2366531A1 (fr) * 1976-09-30 1978-04-28 Dorr Oliver Inc Procede a lit fluidise pour secher des matieres poreuses
FR2528159A1 (fr) * 1982-06-03 1983-12-09 Italiana Essiccatoi Procede et appareil pour le sechage de matieres pulverulentes en general
US6011439A (en) * 1997-09-02 2000-01-04 Ford Global Technologies, Inc. Low power RF amplifier
WO2001012287A2 (en) * 1999-08-17 2001-02-22 Unilever N.V. Apparatus for removing a fluid component from particulized solid materials
EP4303513A1 (de) * 2022-07-04 2024-01-10 Giuseppe Eugenio Ferrari Vorrichtung zum trocknen von körnigem gut

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3856459A (en) * 1972-07-27 1974-12-24 Canterbury Precision Engineers Heaters
FR2366531A1 (fr) * 1976-09-30 1978-04-28 Dorr Oliver Inc Procede a lit fluidise pour secher des matieres poreuses
FR2528159A1 (fr) * 1982-06-03 1983-12-09 Italiana Essiccatoi Procede et appareil pour le sechage de matieres pulverulentes en general
US6011439A (en) * 1997-09-02 2000-01-04 Ford Global Technologies, Inc. Low power RF amplifier
WO2001012287A2 (en) * 1999-08-17 2001-02-22 Unilever N.V. Apparatus for removing a fluid component from particulized solid materials
WO2001012287A3 (en) * 1999-08-17 2001-08-30 Unilever Nv Apparatus for removing a fluid component from particulized solid materials
US6631567B1 (en) 1999-08-17 2003-10-14 Unilever Patent Holdings Bv Apparatus for removing a fluid component from particulized solid materials
EP4303513A1 (de) * 2022-07-04 2024-01-10 Giuseppe Eugenio Ferrari Vorrichtung zum trocknen von körnigem gut

Also Published As

Publication number Publication date
NL6809158A (de) 1969-01-14
BE701295A (de) 1967-12-18
GB1243210A (en) 1971-08-18

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