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WO1996026027A1 - Appareil de regeneration de vieux sable de fonderie - Google Patents

Appareil de regeneration de vieux sable de fonderie Download PDF

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Publication number
WO1996026027A1
WO1996026027A1 PCT/EP1996/000675 EP9600675W WO9626027A1 WO 1996026027 A1 WO1996026027 A1 WO 1996026027A1 EP 9600675 W EP9600675 W EP 9600675W WO 9626027 A1 WO9626027 A1 WO 9626027A1
Authority
WO
WIPO (PCT)
Prior art keywords
container
inlet
plate
rotational axis
oxygen
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/EP1996/000675
Other languages
English (en)
Inventor
Thierry Legiret
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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 Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to EP96902281A priority Critical patent/EP0781178A1/fr
Publication of WO1996026027A1 publication Critical patent/WO1996026027A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
    • B22C5/08—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by sprinkling, cooling, or drying

Definitions

  • Apparatus for the regeneration of used foundry sand The invention relates to an apparatus for the thermal treatment of materials, and particularly for the regeneration of used foundry sand, with the features described in the preamble of Claim 1.
  • An apparatus of this type is known from WO 91/08068.
  • a drum-shaped container is arranged with its rotational axis inclined slightly with respect to the vertical.
  • the container is open at its upper end and equipped with an inlet for an oxygen-containing gas at its lower end; the inlet passes through the bottom wall from below on the rotational axis and projects from the bottom wall into the interior space of the container.
  • the inlet is covered by a bell-shaped cap, which has openings arranged radially with respect to the rotational axis.
  • the known apparatus is filled with used foundry sand and made to rotate slowly around the inclined rotational axis.
  • Oxygen is introduced from below into the organic binder-permeated sand and at the surface is ignited by an ignition flame. A flame front then sweeps uniformly through the sand from top to bottom until the entire hydrocarbon fraction has been burned.
  • the oxygen-containing gas forms preferred flow channels in the sand and thus does not reach all the binder resin particles. After the end of the burning process, a not inconsiderable fraction of the hydrocarbon remains in the regenerated sand.
  • the goal of the invention is to further develop the known apparatus in order to achieve a more effective hydrocarbon combustion.
  • the apparatus according to the present invention is characterized in that the inlet for oxygen-containing gas is constructed of a porous plate.
  • the material introduced into the container for thermal treatment for example, used foundry sand or oil-containing earth, will at least partially cover the porous plate.
  • the oxygen-containing gas is introduced through the porous plate into the container in an area-wise regime and flows at least partly through the material introduced into the container.
  • the formation of preferred channels for the spread of the gas is avoided by this distributed or area-wise introduction of the oxygen-containing gas, with the result that a more uniform formation of the flame front in the material is attained.
  • Another advantage of this area-wise introduction of the oxygen-containing gas is that compaction of the material is avoided.
  • the porous plate may be a sintered metal plate produced by powder metallurgy technology. These sintered metal plates are particularly durable.
  • the plate preferably takes the form of a ceramic plate.
  • the inlet preferably takes the form of a porous cermet plate. Plates of this type combine the favorable characteristics of ceramics and metals.
  • the inlet preferably resides at a distance from the wall of the container. This produces an intervening space between the wall of the container and the inlet, in which the oxygen-containing gas entering the intervening space can be distributed uniformly through the inlet into the interior space of the container. This feature generates an even more uniform distribution of the supplied gas.
  • the inlet lies in the plane of the wall of the container, preferably the bottom wall.
  • the container is constructed in the shape of a cylinder and the longitudinal axis of the container corresponds to the rotational axis wherein the rotational axis is slightly inclined with respect to the vertical.
  • the container is constructed in such a manner that it can tilt about an essentially horizontal axis.
  • This embodiment of the apparatus makes possible a simple emptying of the container.
  • the apparatus is constructed in the form of a drum-shaped container whose rotational axis is slightly inclined with respect to the horizontal.
  • the configuration of the drum-shaped container can be described as quasi-horizontal. The advantage of such an apparatus resides in the corresponding simplification of the suspension of the container.
  • the inlet may, for example, be constructed in the vicinity of the burner, which is situated at one end of the container. This permits easy access to the burner.
  • the inlet should extend at least over a partial section of the container.
  • the upper end of the container should have a flue gas opening through which the flue gas formed during combustion within the container can escape.
  • the upper end should also be equipped with a loading opening through which the container can be loaded with the material to be thermally treated.
  • a discharge opening should be provided at the lower end.
  • the flue gas opening is preferably constructed above the loading opening.
  • Subject container can preferably oscillate about the rotational axis.
  • the container can preferably move about the rotational axis to an angle of up to 180;.
  • the oscillating motion of the container induces the circulation of the material present in the container, thereby promoting the thermal treatment of the material.
  • This turning motion by the container results in transport of the material within the container from the loading opening to the discharge opening and thus supports the continuous operation of the apparatus.
  • the oxygen-containing gas is preferably led to the inlet through movable feed lines.
  • Movable feed lines make it possible to achieve sealing in a relatively simple manner.
  • the feed line is preferably a flexible feed line, for example, a hose.
  • the inlet can be supplied with the oxygen-containing gas through one or several feed lines.
  • the use of several feed lines affords a more uniform gas distribution.
  • the inlet may also be subdivided into individually separate sections with one feed line leading to each inlet section.
  • a flow device can be provided in each feed line.
  • the flow device can be a valve, preferably an electrically operated valve. Placing a flow device in the feed line makes it possible to make suitable adjustments in the flow velocity, pressure, and/or volumetric flow rate of the gas to the inlet. It may be advantageous to feed different volumes or gas pressures to individual subsections of the inlet. For example, it may be advantageous to supply higher quantities of gas to zones in which the fraction of untreated material is still relatively high.
  • the apparatus includes a cooler, which is inserted after the container.
  • the material treated thermally in the container is introduced into the cooler, where the hot material is cooled.
  • the waste heat from the material is preferably used to preheat the combustion air for the burner in the container.
  • the cooler is constructed as an air cooler for this purpose .
  • the apparatus preferably includes an analytical device for determining the flue gas composition and, connected to said analytical device, a control device that controls the supply of oxygen-containing gas to the container.
  • the flue gas composition can be analyzed continuously.
  • the emission of, for example, NOx can be optimized through the control device and the flue gas composition determined by the analytical device.
  • a reduction in the carbon monoxide in the flue gas can be realized by an appropriate addition of oxygen.
  • the inlet covers between 25% and 75% of the area of the bottom wall.
  • the inlet preferably covers the largest possible area, and particularly the entire bottom wall.
  • An improved combustion is readily generated when the inlet covers a circular area of the bottom wall of a cylindrical container which has a diameter of 100 mm to 300 mm.
  • Figure 1 shows an apparatus according to the present invention in side view
  • FIG. 2 shows an enlarged section of the apparatus according to Figure 1;
  • Figure 3 shows a schematic representation of the structure of a second exemplary embodiment of an apparatus
  • Figure 4 shows the container of an apparatus according to
  • Figure 5 shows the container according to Figure 4, in side view from the left.
  • Figure 1 shows, in side view, an apparatus 1 for the thermal treatment of, for example, used foundry sand.
  • the apparatus 1 comprises a drum-shaped container 2, which is supported in a frame 3 so that it can rotate about a rotational axis 11.
  • the frame 3 is, in turn, supported in a stand 4 by means of bearings 5, so that it can be tilted about a horizontal axis, which in Figure 1 is perpendicular to the plane of the drawing.
  • the drum-shaped container 2 comprises a side wall 6 approximately in the shape of a cylinder wall and an approximately disk-shaped bottom wall 7.
  • a connection 8 for an oxygen feed line 9 is provided on the bottom wall 7; this connection is located in the middle of bottom wall 7 in the area of the rotational axis.
  • the oxygen feed line 9 is fed from an oxygen supply 10, which is known per se.
  • FIG. 2 shows in greater detail the area of the transition from the side wall to the bottom wall.
  • the side wall 6 has a sandwich-type construction, with an outer shell 12, preferably made of stainless steel, an insulation layer 13 adjacent to the inside of the shell 12, and a refractory lining 14, which is attached on the inner side of the insulation layer 13.
  • the bottom wall 7 is fabricated in one piece with the shell 12 out of stainless steel and is essentially flat.
  • a porous plate 15, preferably produced from a sintered metal, is situated parallel to the bottom wall 7 at a distance from the bottom wall. This creates a disk-shaped intermediate space between the bottom wall 7 and the plate 15.
  • the connection 8 is situated in the center of the bottom wall 7 and points away from the interior space of the container.
  • the plate 15 terminates the cylindrical interior space of the container, which is delimited radially by the inside wall of the refractory lining 14.
  • This apparatus for the regeneration of used foundry sand functions in the following manner:
  • the used, binder-permeated molding sand is introduced into container 2 of apparatus 1.
  • the container 2 is then rotated about its vertical axis, which is slightly inclined with respect to the vertical, thus inducing a moderate tumbling action in the contents of the container 2.
  • Oxygen is then supplied into the intermediate space under the plate 15 from the oxygen supply 10 through the oxygen feed line 9 and the connection 8.
  • the porosity of the plate permits the oxygen to permeate through the plate and reach the introduced sand.
  • the oxygen flows through the sand, which is undergoing moderate motion, and exits at its surface.
  • the hydrocarbon-loaded sand is heated by an ignition flame (not shown) to such an extent that the hydrocarbons react exothermically with the through-flowing oxygen.
  • the reaction heats the surrounding sand, and the area of the oxidation reaction spreads and migrates through the entire sand volume as a flame front, with the result that as oxygen is being supplied the hydrocarbons present are burned to form carbon monoxide and water.
  • the reaction rate, and thus the evolution of heat and the velocity of the spreading flame front, can be controlled by adjusting the oxygen.
  • the container 2 can be tilted about the horizontal axis and emptied.
  • the porous plate 15 situated at the bottom of the container 2 causes the oxygen-containing gas to enter the sand from below along the axial direction over a large cross section. This achieves a uniform flow within the sand volume.
  • the oxygen enters the sand in a quasi-pointwise manner at the center of the bottom plate and is distributed from there in both axial and radial directions. Higher gas velocities occur as a result of the initially small cross section, which lead to the formation of preferred paths for dissemination of the oxygen in the sand volume.
  • the sand is nonuniformly permeated by oxygen in the known apparatuses, with the result that regions still loaded with hydrocarbons can remain in the sand volume. Furthermore, locally high oxygen concentrations can lead to combustion of an explosive character.
  • FIG. 3 shows a second exemplified embodiment of an apparatus according to the present invention.
  • This apparatus comprises a drum-shaped container 2.
  • the container 2 is supported in such a manner that it can rotate about a rotational axis 11.
  • the suspension of the container 2 is not depicted.
  • the rotational axis 11 is slightly inclined with respect to the horizontal.
  • a burner 27 is situated on the lower end 16 of the container 2.
  • the upper end 19 has a loading opening 17, which communicates with a loading device. Used foundry sand, for example, is introduced into the container 2 through the loading device 18.
  • a screw conveyer (not shown) can be present in the loading device 18.
  • a flue gas conduit 20, through which fumes flow out of the container 2, is situated on the upper end 19.
  • the flue gas conduit 20 communicates with an opening 28 in the container 2.
  • the container 2 is connected to oxygen feed lines 9a,
  • a flow device 24a, 24b, 24c which in this case is an electrically operated valve, is provided in each oxygen feed line 9a, 9b, 9c.
  • Each valve is connected to a control device 25.
  • the control device 25 is also connected to an analytical device 26 provided for determination of the flue gas composition.
  • the control device 25 can optionally be connected to temperature sensors located in the container 2.
  • the container 2 can oscillate around its rotational axis 11, and in this case the container 2 can rotate 180; about the rotational axis.
  • the swiveling process leads to a rocking motion by the container 2, with the result that material introduced into the container 2 through the loading opening 17 reaches the lower region of the container 2 and is there removed from the container 2 through the discharge opening 21.
  • the side wall 6 of the container 2 has a sandwich-type construction, with an outer shell 12, an insulation layer 13 adjacent to the inner side of the shell 12, and a refractory lining 14 attached on the inner side of the insulation layer 13.
  • a porous plate 15 is located in the area of the burner.
  • the apparatuses described above can be used for the regeneration of used foundry sand. They can also be used, for example, for the treatment of soil contaminated with oil products.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)

Abstract

L'invention concerne un appareil de traitement thermique de matériaux, destiné notamment à la régénération de vieux sable de fonderie. Cet appareil comprend un récipient qui peut tourner autour d'un axe de rotation et qui présente un orifice d'entrée de gaz contenant de l'oxygène. Un brûleur est placé dans le récipient, dont la flamme est dirigée sur le matériau introduit dans celui-ci aux fins d'un traitement thermique. L'orifice d'entrée de gaz contenant de l'oxygène est constitué par une plaque poreuse. Dans un mode de réalisation préférée, cette plaque poreuse est une plaque métallique frittée.
PCT/EP1996/000675 1995-02-24 1996-02-10 Appareil de regeneration de vieux sable de fonderie Ceased WO1996026027A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP96902281A EP0781178A1 (fr) 1995-02-24 1996-02-10 Appareil de regeneration de vieux sable de fonderie

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1995106539 DE19506539A1 (de) 1995-02-24 1995-02-24 Vorrichtung zum Regenerieren von Gießereialtsand
DE19506539.5 1995-02-24

Publications (1)

Publication Number Publication Date
WO1996026027A1 true WO1996026027A1 (fr) 1996-08-29

Family

ID=7754980

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1996/000675 Ceased WO1996026027A1 (fr) 1995-02-24 1996-02-10 Appareil de regeneration de vieux sable de fonderie

Country Status (3)

Country Link
EP (1) EP0781178A1 (fr)
DE (1) DE19506539A1 (fr)
WO (1) WO1996026027A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7409461B1 (ja) 2022-10-20 2024-01-09 住友金属鉱山株式会社 粉体製造装置および粉体製造方法

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1107425A (en) * 1964-02-28 1968-03-27 Rheinische Kalksteinwerke Revolving tubular kilns
US4266931A (en) * 1979-02-01 1981-05-12 Holger Struckmann Apparatus and method of heating particulate material
US4353534A (en) * 1979-12-24 1982-10-12 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Apparatus for supplying gas to a revolving cylindrical furnace
WO1988006698A1 (fr) * 1987-02-25 1988-09-07 Westinghouse Electric Corporation Commande de combustion automatique pour bruleur rotatif
US4948365A (en) * 1989-05-24 1990-08-14 Zond Systems, Inc. High-temperature, gas-burning furnace
US4961390A (en) * 1990-02-07 1990-10-09 Westinghouse Electric Corp. Perforated plugs for air holes in a rotary combustor
WO1991008068A1 (fr) * 1989-11-28 1991-06-13 Pio Fumagalli Procede de recuperation par grillage du sable de fonderie use
US5110288A (en) * 1990-02-08 1992-05-05 Rothschild John J Gravity flow thermal process for reclaiming foundry sand
EP0618407A1 (fr) * 1993-03-29 1994-10-05 Chiyoda Corporation Four industriel pourvu d'un brûleur à régénération du type rotatif

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1107425A (en) * 1964-02-28 1968-03-27 Rheinische Kalksteinwerke Revolving tubular kilns
US4266931A (en) * 1979-02-01 1981-05-12 Holger Struckmann Apparatus and method of heating particulate material
US4353534A (en) * 1979-12-24 1982-10-12 Fried. Krupp Gesellschaft Mit Beschrankter Haftung Apparatus for supplying gas to a revolving cylindrical furnace
WO1988006698A1 (fr) * 1987-02-25 1988-09-07 Westinghouse Electric Corporation Commande de combustion automatique pour bruleur rotatif
US4948365A (en) * 1989-05-24 1990-08-14 Zond Systems, Inc. High-temperature, gas-burning furnace
WO1991008068A1 (fr) * 1989-11-28 1991-06-13 Pio Fumagalli Procede de recuperation par grillage du sable de fonderie use
US4961390A (en) * 1990-02-07 1990-10-09 Westinghouse Electric Corp. Perforated plugs for air holes in a rotary combustor
US5110288A (en) * 1990-02-08 1992-05-05 Rothschild John J Gravity flow thermal process for reclaiming foundry sand
EP0618407A1 (fr) * 1993-03-29 1994-10-05 Chiyoda Corporation Four industriel pourvu d'un brûleur à régénération du type rotatif

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7409461B1 (ja) 2022-10-20 2024-01-09 住友金属鉱山株式会社 粉体製造装置および粉体製造方法

Also Published As

Publication number Publication date
DE19506539A1 (de) 1996-08-29
EP0781178A1 (fr) 1997-07-02

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