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
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/32—Packing elements in the form of grids or built-up elements for forming a unit or module inside the apparatus for mass or heat transfer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/04—Solvent extraction of solutions which are liquid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/04—Solvent extraction of solutions which are liquid
  • B01D11/0426—Counter-current multistage extraction towers in a vertical or sloping position
  • B01D11/043—Counter-current multistage extraction towers in a vertical or sloping position with stationary contacting elements, sieve plates or loose contacting elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D11/00—Solvent extraction
  • B01D11/04—Solvent extraction of solutions which are liquid
  • B01D11/0426—Counter-current multistage extraction towers in a vertical or sloping position
  • B01D11/0434—Counter-current multistage extraction towers in a vertical or sloping position comprising rotating mechanisms, e.g. mixers, rotational oscillating motion, mixing pumps
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/26—Treatment of water, waste water, or sewage by extraction
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/32—Details relating to packing elements in the form of grids or built-up elements for forming a unit of module inside the apparatus for mass or heat transfer
  • B01J2219/322—Basic shape of the elements
  • B01J2219/32203—Sheets
  • B01J2219/3221—Corrugated sheets
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/32—Details relating to packing elements in the form of grids or built-up elements for forming a unit of module inside the apparatus for mass or heat transfer
  • B01J2219/322—Basic shape of the elements
  • B01J2219/32203—Sheets
  • B01J2219/32213—Plurality of essentially parallel sheets
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/32—Details relating to packing elements in the form of grids or built-up elements for forming a unit of module inside the apparatus for mass or heat transfer
  • B01J2219/322—Basic shape of the elements
  • B01J2219/32203—Sheets
  • B01J2219/32224—Sheets characterised by the orientation of the sheet
  • B01J2219/32227—Vertical orientation
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/32—Details relating to packing elements in the form of grids or built-up elements for forming a unit of module inside the apparatus for mass or heat transfer
  • B01J2219/322—Basic shape of the elements
  • B01J2219/32203—Sheets
  • B01J2219/32255—Other details of the sheets
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/32—Details relating to packing elements in the form of grids or built-up elements for forming a unit of module inside the apparatus for mass or heat transfer
  • B01J2219/324—Composition or microstructure of the elements
  • B01J2219/32408—Metal
• • 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
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/32—Details relating to packing elements in the form of grids or built-up elements for forming a unit of module inside the apparatus for mass or heat transfer
  • B01J2219/324—Composition or microstructure of the elements
  • B01J2219/32483—Plastics

Definitions

• the present invention pertains to chemical process towers and, more particularly, to agitated extraction columns assembled with structured packing.
• liquid-liquid contact art it is highly desirable to utilize methods and apparatus that efficiently improve the quantity of mass transfer occurring in process towers. This is generally accomplished with countercurrent liquid extraction systems. Liquids of such systems flow continuously and countercurrently through one or more chambers which may have specially designed apparatus mounted therein. Apparatus of this type may include agitators for affecting the physical properties (e.g., droplet size) of the liquid and tower packing which serves to obstruct the direct flow of the liquids. Packing also provides better contact between lighter rising liquids and heavier settling liquids, and better contact means higher efficiency.
• agitators for affecting the physical properties (e.g., droplet size) of the liquid and tower packing which serves to obstruct the direct flow of the liquids. Packing also provides better contact between lighter rising liquids and heavier settling liquids, and better contact means higher efficiency.
• Liquid-liquid process towers are generally constructed to provide descending heavy liquid flow from an upper portion of the tower and ascending li.ght liquid from a lower portion of the tower. It has been found desirable in the liquid-liquid contact portion of the prior art to provide apparatus and methods affording efficient mass transfer, or liquid-liquid contact, whereby contact of the fluids can be accomplished with a minimum pressure drop through a given zone of minimum dimensions. High efficiency and low pressure drop are important design criteria in liquid-liquid extraction operations. Sufficient surface area for liquid-liquid contact is necessary for the primary function in the reduction or elimination of heavy liquid entrainment present in the ascending lighter liquid.
• the structured packing array in the column or in the calming zone of agitated extraction systems it is necessary for the structured packing array in the column or in the calming zone of agitated extraction systems to have sufficient surface area in both its horizontal and vertical plane so that fractions of the heavy constituents are conducted downwardly, and the lighter liquid is permitted to rise upwardly through the packing with minimum resistance.
• the structured packing array in the column or in the calming zone of agitated extraction systems it is necessary for the structured packing array in the column or in the calming zone of agitated extraction systems to have sufficient surface area in both its horizontal and vertical plane so that fractions of the heavy constituents are conducted downwardly, and the lighter liquid is permitted to rise upwardly through the packing with minimum resistance.
• a passive liquid-liquid tower (no mechanically induced agitation) , generally includes a plurality of stacked layers affording compatible and complemental design. Such a design is set forth, shown and discussed in U.S. Pat. 5,185,106. In such a passive column, each layer utilizes the velocity and kinetic energy of the fluids to perform the dual function of eliminating heavy liquid entrainment in the ascending liquid phase and the thorough contacting of the light and heavy liquids to accomplish sufficient separation or extraction of the fluids into desired components.
• the liquid introduced at or near the top of the column and withdrawn at the bottom is effectively engaged by the separate liquid stream being introduced at or near the bottom of the column and withdrawn at the top.
• the critical feature in such methods and apparatus is to insure that the first and second liquids achieve the desired degree of contact with each other so that the planned mass or energy transfer occurs at the designed rate.
• the internal structure may be active or passive depending on whether or not it is power-driven externally. There are, however, established reasons for utilizing active systems.
• One prior art perception is that passive, packed columns give poor results compared to active columns.
• One of the problems is channeling which results in very little contact between liquids.
• Another problem is the size of the first liquid phase droplets dispersed into a second continuous liquid phase. Through agitator systems, the droplets of a first liquid can become extremely fine and remain dispersed in a second liquid for longer periods of time.
• An active extraction column is the Scheibel type extraction apparatus as shown in U.S. Patent No. 2,493,265.
• One aspect of the invention set forth in this reference comprises a substantially vertical column or chamber provided with a mixing section in which one or more agitators are installed to promote intimate contact between the liquids so as to cause equilibrium contact between them.
• the mixing chambers are calming sections where layers of fibrous packing, preferably of the self-supporting type, as for example, a roll of tubular knitted wire mesh, are mounted.
• the packing in the calming sections stops the circular motion of the liquids and permits them to separate.
• the heavier liquid settles out and flows downwardly, countercurrently to and through a rising stream of lighter liquid.
• the rising stream of lighter liquid flows countercurrently to and through a descending stream of heavier liquid.
• the agitators are mounted on a central shaft extending through the column and the shaft is rotated by any suitable device such as a motor.
• Other countercurrent contractor designs are set forth and shown in U.S. Patent No.
• a first liquid phase is dispersed into a second continuous phase in the form of droplets.
• the droplets can become extremely fine through agitation and it is very desirable to have the dispersed phase droplets remain dispersed throughout the entire column.
• metal surfaces are more efficient for keeping organic phases dispersed than Teflon surfaces which are more effective for keeping aqueous phases dispersed.
• the function of the packing within agitated-packed systems is mainly to provide a restriction or "roadblock" to increase the number of dispersed phase droplets per unit volume of counter flowing continuous phase.
• the present invention pertains to agitated extraction columns and more particularly one aspect of the present invention pertains to countercurrent, liquid- liquid extraction systems comprising a substantially vertical column having a central axis therethrough and including a series of axially alternating transverse calming and mixing sections therein. Agitation devices are disposed within each of the mixing sections for exerting a non-vertical thrust to the liquid flowing therein. Structured packing is mounted within the calming sections and between the mixing sections, and the structured packing mounted within the calming sections comprises at least one layer of corrugated contact plates disposed in generally face-to-face relationship for facilitating the flow of liquid therebetween.
• the above described invention includes corrugated plates disposed with opposed corrugations inclined oppositely one to the other and at an angle relative to the vertical axis of the column.
• the corrugated plates disposed within the calming sections have corrugations orientated at an angle on the order of 45° relative to the axis of the column.
• the corrugations of the plates may be formed with a height on the order of one-half inch and may have a generally smooth surface finish.
• the plates are foil-like and are formed from metal.
• the plates are either formed from or coated with a class of engineering plastics including Teflon and polypropylen .
• the above described invention includes at least two axial layers of packing, transversely disposed within each of the calming sections.
• the packing is preferably arranged with at least a second layer of packing rotated on the order of 90° relative to a first layer of packing to enhance the edge sealing between said packing and said column.
• a third layer of packing is provided contiguous to the second layer of packing and rotated on the order of 90° relative thereto and so on if there are more than three layers.
• the present invention relates to a method of counter-current liquid-liquid extraction of the type performed in a substantially vertical column with a series of axially alternating, transverse calming and mixing sections.
• the method comprises the steps of providing the mixing sections with at least one agitator therein for exerting a non-vertical thrust to the liquid and providing structured packing of the corrugated variety.
• the structured packing is then mounted within the calming sections and the structured packing with at least one layer of corrugated contact plates disposed in generally face-to-face relationship within said calming sections.
• the method may further include the steps of disposing the corrugated metal sheets with opposed corrugations inclined oppositely one to the other and at an angle relative to the vertical axis of the column.
• FIG. 1 is a diagrammatic elevational schematic of a plant illustrating an agitated extraction system in accordance with the principles of the present invention
• Fig. 2 is a side elevational cross-sectional view of a diagrammatic illustration of an agitated-packed column constructed in accordance with the principles of the present invention
• FIG. 3A is a graphical representation illustrating the distribution of acetone between toluene and water with the system of FIG. 1;
• Fig. 3B is a graph of theoretical stages per meter versus RPM of the agitator paddles for a first structured packing size with the system of FIG. 1,*
• Fig. 4 is a graph of a theoretical stages per meter versus RPM for a second structured packing size with the system of FIG. 1;
• Fig. 5 is a Stichlmair-type plot showing maximum theoretical stages per meter for versus total flow for the two different structured packing sizes of Figs. 3 and 4;
• Fig. 6 is a graph of volumetric efficiency verses total flow with mass transfer from the continuous to dispersed phase for the structured packing of Figs. 3 and 4;
• Fig. 7 is an enlarged fragmentary exploded perspective view of the assembly of the structured packing of Fig. 2 in accordance with the principles of the present invention.
• FIG. 1 there is shown a diagrammatic schematic of one embodiment of an agitated- packed column system constructed in accordance with the principles of the present invention.
• the system 10 comprises a column 12 constructed with a plurality of calming sections 14 and mixing sections 16 therein.
• the assembly of the column 12 provides a counter-current, liquid-liquid extraction system having a shaft 18 positioned along a central axis 26.
• the shaft 18 is constructed with paddles 28 disposed within each mixing section 16 for exerting a non-vertical thrust to liquid flowing therein.
• Each calming section 14 further includes structured packing 20 mounted therein, between the mixing sections 16 with the structured packing comprising at least one layer of corrugated contact plates disposed in generally face-to-face relationship for facilitating the flow of liquid there between as will be described in more detail below.
• Fig. 1 is a schematic illustration which shows a simple system for illustrating the principles of the present invention. The schematic illustration is itself a diagram of a pilot plant operation, but is equally applicable and convertible to a commercial system by those skilled in the art.
• a variable speed drive motor 22 is secured at the top 24 of column 12 for powering mixing sections 16.
• the drive motor 22 rotates the shaft 18 extending down the axis 26of the column 12.
• Paddles 28 are installed in the mixing sections 16 to generate the agitation of the liquids therein from the rotation of the shaft 18 as the liquids pass in countercurrent flow therethrough.
• the agitation imparted thereto is designed to reduce the size of liquid phase droplets dispersed into another continuous phase liquid.
• Vertical blades 29 are thus assembled to paddles 28 to create agitation with a non-vertical thrust. Agitation from blades 29 and the like has been shown to produce an extremely fine dispersed droplet configuration in such assemblies.
• the first, or heavier, liquid 30 is thus shown to be provided in a reservoir or drum 32 adjacent the column 12 and pumped to the top 24 of said column by a r pump 34.
• a flow measurement system 36 is diagrammatically shown for monitoring the liquid flow rates.
• the liquid 30 is forced from pump 34 through conduit 38 into the top 24 of column 12 while lighter liquid 40 is pumped into the bottom 42 of the column 12.
• Lighter liquid 40 shown herein in the form of organic solvent, is provided in a drum or reservoir 44 and forced through pump 46 through pipes 48 into the bottom 42 of the column 12.
• a flow calibration measurement system 49 is likewise shown.
• a pump 54 may be utilized to force the liquid 30 into the drum 52, which liquid 30 is generally referred to as aqueous underflow or raffinate 56.
• the lighter, organic solvent 40 passes upwardly through column 12 and is carried away from the top 24 through discharge line 60 past vent 62 into a reservoir, shown herein as a drum 64, where it is accumulated as an organic overflow or extract 66.
• Mesh pad coalescers (not shown) were used in the pilot plant tests as is conventional in the chemical process tower art.
• Fig. 2 there is shown the column 12 of Fig. 1 with the variable speed drive motor 22 disposed thereabove.
• the calming sections 14 are shown in more detail.
• Each section 14 contains structured packing 20 in three distinct layers.
• the structured packing 20 in each of the calming sections 14 is comprised of a first bottom layer 67 of corrugated packing facing a first direction with a second layer 68 of corrugated packing disposed thereabove and orientated into a second direction.
• the orientation of layers 67 and 68 are described in more detail below.
• a third packing layer 69 is disposed above second layer 68, which third layer 69 is also rotated relative to second layer 68.
• the bottom 42 of the tower 12 is shown to be constructed with a sufficient axial length to provide for an organic solvent distributor 70.
• the distributor 70 distributes the flow of the lighter fluid 40 upwardly through column 12 while an aqueous feed distributor 72 is disposed in the upper region of the column 12 for distributing the heavier liquid 30 downwardly therein.
• This particular system design has been utilized in the analysis of the present invention as part of pilot plant tests utilizing a column having a relatively small diameter (on the order of 3 inches) . Other test parameters and results will be set forth below.
• one aspect of the present invention is the utilization of corrugated metal packing in the calming sections 14.
• the layers 67, 68 and 69 of calming section 14 are rotated 90° relative to each other and are formed of smooth, impervious corrugated metal structured packing.
• This packing configuration is used in the present invention to replace the mesh packing of the Scheibel mesh-type extraction apparatus of U.S. Patent 2,493,265. It was found during the test of this assembly that this substitution permitted a six fold increase in processing capacity to be realized at volumetric efficiencies which are comparable, if not higher, than prior art designs.
• Pilot plant extraction column tests were performed to demonstrate the performance of an agitated-packed extraction column of the type shown in Fig. 2 with a standard acetone-water-toluene system.
• the two extraction columns evaluated were patterned after the original Scheibel mesh column as shown in U.S. Patent No.
• the maximum theoretical stages per meter ranged from 3.83 at 10 m 3 (m 2 /hr) to a maximum of 5.91 at 20 m 3 /(m 2 hr) , with a decrease at higher processing rates to 2.11 stages/meter at a combined throughput of 49.89 m 3 /(m 2 hr) .
• the maximum volumetric efficiency (at optimum rpm) increased from 38.3 HR "1 at a combined throughput of 10 m 3 / (m 2 hr) to a maximum of 186.8 HR -1 at 40 m 3 / (mhr) and then it fell off to 106 HR "1 at 49.89 m 3 / (m 2 hr) .
• Fig. 3A the equilibrium distribution of acetone between reagent grade toluene and water (steam condensate) phases at room temperature may be seen. These data were obtained by performing shake tests with a 1 liter round bottom flask. Compositions of the resulting raffinate and extract phases were determined by gas chromatography.
• FIG. 1 illustrates a simplified schematic of the extraction pilot plant from which the data was taken that is presented herein.
• the pilot plant included a 3" diameter agitated column 12 with variable speed paddles 28 installed in mixing sections 16, metered supplies of feed 30 and solvent 40, and collection systems for an organic extract overflow 66 and a raffinate underflow 56.
• the organic toluene phase was dispersed in the continuous aqueous phase so the liquid-liquid interface was located at the top of the extraction column.
• Specific geometries of the agitated column 12 tested may be seen in Figures 3B, 4, 5 and 6.
• Packing for the 3/8" crimp column was fabricated from structured packing sold under the trademark Gempak ® which is a registered trademark of Glitsch, Inc.
• the Gempak elements were constructed in a 4-3/4" thickness with a 3" outside diameter and were drilled with a V hole axially through the center thereof for receipt of the shaft 18 therethrough (See FIG. 7) .
• Packing for the W crimp Gempak ® columns was fabricated from plain sheet metal elements (no lances, perforations or holes) by welding three (3) 1 " thick x 3" diameter discs of the GempakTM together to form a 4 ⁇ _" long (high) element. Each disc was rotated 90° to the adjacent disc before welding. Again, a V.” diameter hole was drilled axially through the center of each finished element for passage of the agitator shaft 18 therethrough.
• volumetric efficiency is the product of the total flow in units of m 3 /(m 2 hr) and the number of theoretical stages per meter.
• volumetric efficiency has the units of HR "1 and is inversely proportional to the volume of column required to do a given extraction job.
• FIG.7 there is shown an enlarged, exploded, perspective view of a preferred embodiment of the structured packing 20 of the present invention disposed within the calming sections 14 of a tower 12 in layers 67, 68 and 69, which correspond to the description in FIG. 2.
• the individual layers 67, 68 and 69 are referred to generally as layers 100.
• the structured packing 20 is provided in an assembly of multiple packing layers 100.
• Each layer 100 of packing 20 comprises a plurality of corrugated sheets 102, the corrugations of which are disposed at an angle relative to the tower axis 18 and angularly oriented one to the other in face-to-face relationship.
• a somewhat similar structured packing array is also shown in U.S. Patent No.
• the plurality of layers are rotationally oriented on the order of 90° one to the other as represented by phantom line 111 for bi ⁇ directional lateral dispersion and full distribution of the liquids passing therethrough.
• This rotational c relationship between layers as represented by line 111 affords not only even liquid distribution but also enhances the sealing of the assembly thereof relative to the round walls of column 12.
• Thi ⁇ rotational relationship between layers affords not only even liquid distribution and improved sealing of the assembly relative to the round walls of column 12, but also increases the dispersed phase holdup in the calming sections of said column.
• a single layer 100 of corrugated sheets 102 seals best against the round inside column walls 104 along its ends 110 which may be cut more precisely to size.
• the multiple packing layers 100 are each constructed with a central aperture 199 formed therein.
• the apertures 199 of layers 100 are adapted for receipt of the shaft 18 therethrough for permitting assembly of the paddles 28 in the adjacent mixing section 16 and the rotation thereof. In this manner, agitation may be imparted to the liquids flowing therein, as described above.
• the paddles 28, blades 29, shaft 18, packing layers 100 and the side walls 104 of tower 12 are coated with plastic such as polypropylene, Teflon (a trademark of Dupont) or Kymar (a trademark of Pennwalt Corp.) .
• the packing layers and other parts, such as paddle blades 29 may actually be formed of such plastics.
• Such plastic coatings can be applied by dip coating and the like and are most useful when using the present invention to disperse an aqueous liquid into a continuous organic liquid because aqueous liquids coalesce on metals.
• FIGS. 1, 2 and 7 illustrate a countercurrent, liquid-liquid extraction system 10 comprising a substantially vertical column 12 having a central axis 18 therethrough and including a series of axially alternating transverse calming sections 14 and mixing section 16 therein.
• Agitation means in the form of paddles 28 are disposed within each of the mixing sections 16 for exerting a non-vertical thrust to the liquid flowing therein.
• At least one layer of structured packing 20 is mounted within each of the calming sections 14 and between the mixing sections 16 and said structured packing mounted within said calming sections comprises at least one layer of corrugated contact plates or sheets 102 disposed in generally face-to-face relationship for facilitating the flow of liquid therebetween.
• the corrugated sheets 102 disposed within the calming sections may, as shown, have the corrugations oriented at an angle on the order of 45° relative to the axis 18 of the column 12.
• the corrugations of the sheets 102 may be formed with a height on the order of one- quarter inch to three inches, depending on the size of the column 12, and may have a generally smooth surface finish as described herein, or the sheets may include apertures.
• the sheets 102 are foil-like and are formed from metal. As described above, the sheets 102 may be formed from plastic or coated therewith.
• the preferred embodiment of the above described invention includes at least two axial layers 100 of packing 20 transversely disposed within each of the calming sections 14. As many as five or more layers are contemplated in certain conventional applications. In this particular embodiment, the packing is rotated 90° relative to a first layer of packing to enhance the edge sealing between said packing and the inside walls 104 of the column 12.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Hydrology & Water Resources (AREA)
• Thermal Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Extraction Or Liquid Replacement (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Seeds, Soups, And Other Foods (AREA)

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Cited By (6)

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Citations (3)

• 1996
  • 1996-08-12 WO PCT/US1996/012997 patent/WO1997010886A1/en not_active Application Discontinuation
  • 1996-08-12 CA CA002232382A patent/CA2232382A1/en not_active Abandoned
  • 1996-08-12 CN CN96198114A patent/CN1201400A/zh active Pending
  • 1996-08-12 KR KR1019980701988A patent/KR19990045745A/ko not_active Application Discontinuation
  • 1996-08-12 BR BR9610523A patent/BR9610523A/pt not_active Application Discontinuation
  • 1996-08-12 AU AU68443/96A patent/AU6844396A/en not_active Abandoned
  • 1996-09-09 TW TW085111006A patent/TW325413B/zh active
  • 1996-09-10 AR ARP960104296A patent/AR003544A1/es unknown
  • 1996-09-18 CO CO96049681A patent/CO4560416A1/es unknown

Patent Citations (3)

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