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US20100116746A1 - Inverse Fluidization for Purifying Fluid Streams - Google Patents

Inverse Fluidization for Purifying Fluid Streams Download PDF

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Publication number
US20100116746A1
US20100116746A1 US12/437,349 US43734909A US2010116746A1 US 20100116746 A1 US20100116746 A1 US 20100116746A1 US 43734909 A US43734909 A US 43734909A US 2010116746 A1 US2010116746 A1 US 2010116746A1
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Prior art keywords
oil
metal oxide
fluid system
aerogel
nanoporous metal
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Abandoned
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US12/437,349
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English (en)
Inventor
Robert Pfeffer
Jose Quevedo
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New Jersey Institute of Technology
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New Jersey Institute of Technology
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Priority to US12/437,349 priority Critical patent/US20100116746A1/en
Publication of US20100116746A1 publication Critical patent/US20100116746A1/en
Priority to US13/852,220 priority patent/US9216915B2/en
Abandoned legal-status Critical Current

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    • 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
    • C02F1/24—Treatment of water, waste water, or sewage by flotation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D15/00—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor
    • B01D15/02—Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor with moving adsorbents
    • 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
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
    • B01J20/28047—Gels
    • 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
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J20/28078—Pore diameter
    • B01J20/2808—Pore diameter being less than 2 nm, i.e. micropores or nanopores
    • 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
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/32—Hydrocarbons, e.g. oil

Definitions

  • HD Q-PAC coalescing medium
  • a coalescing medium such as, for instance, that supplied by Lantec Products (www.lantecp.com) under the name of HD Q-PAC.
  • a unit using HD Q-PAC material was designed to handle 1900 gallons per minute (gpm) of water with an oil concentration of 4250 milligrams/liter (mg/l).
  • a coalescing system is also supplied by Pall Corporation of East Hills, N.Y. under the name of AquaSep® Plus.
  • Pall AquaSep Plus Liquid/Liquid Separation System with Coalescer in a Horizontal Housing illustrated in FIG. 2 of Pall Corporation Data Sheet GAS-4105g, available at www.pall.com, coalescer elements are stacked horizontally on top of a separator element. The purpose is to ensure equally distributed flow through the separators. After the separator elements, a settling zone is provided for the separation of the two liquid phases. The pressure drop through this system is 2 pounds per square inch differential (psid) when new and it has to be replaced when the pressure drop reaches 15 psid.
  • psid pounds per square inch differential
  • activated carbon The most commonly used material for removing organic compounds from liquids and gases is activated carbon.
  • Activated carbon is highly porous and thus provides large internal surfaces for adsorbed molecules to reside.
  • purification methods based on adsorption by activated carbon as well as other purification techniques such as reverse osmosis and ultrafiltration strongly depend on temperature and their removal capacities and/or efficiencies may be affected under operating temperatures higher than ambient.
  • Organoclays such as bentonite modified with quaternary amine cations, also can be used to remove oil from water and they are particularly suitable for removal of large organic molecules of low solubility.
  • One of these clay-based products is sold by Biomin Inc. (www.biomininc.com) under the name of OilSorbTM.
  • a packed bed of organoclay granules is used before the activated carbon to improve its adsorption efficiency, since activated carbon can quickly be blinded by oils that clog its porous surface.
  • the invention is directed to a method for removing a contaminant, e.g., an oil, from a fluid system.
  • the method comprises contacting the fluid system with an inversely fluidized material, thereby removing at least a portion of the contaminant from the fluid system.
  • the inversely fluidized material is a porous material, preferably a nanoporous material, e.g., aerogel particles.
  • the inversely fluidized material is hydrophobic.
  • the invention is directed to a method for purifying a fluid system.
  • the method comprises directing the fluid system to an inverse fluidized bed which includes a material, e.g., a porous material such as aerogel particles, having a density lower than the density of the fluid system; and contacting the fluid system with the material, thereby removing contaminants from the fluid phase system to obtain a purified fluid.
  • a material e.g., a porous material such as aerogel particles
  • the invention is directed to a method for removing an oil from an aqueous system.
  • the method includes contacting the aqueous system with an inversely fluidized hydrophobic material, thereby removing at least a portion of the oil from the aqueous system.
  • the invention is directed to a fluidized bed which includes nanoporous particles and a fluidizing medium, wherein the nanoporous particles have a density that is lower than that of the fluidizing medium.
  • the invention is useful in purifying waste or other fluid streams such as discharged or recycled in refineries, manufacturing or processing facility, and in many other instances.
  • the inverse fluidization method and apparatus disclosed herein are flexible and can remove contaminants in a broad size of droplets, for instance they can remove droplets larger than 5 microns.
  • practicing the invention can replace or can be used in conjunction with a system such as the AquaSep Plus Liquid/Liquid Separation System with Coalescer in a Horizontal Housing discussed above and/or one or more techniques illustrated, for instance, in FIG. 1 .
  • the inverse fluidization described herein shows high removal efficiency, low and constant pressure drop (when operating above the minimum fluidization velocity), good mixing between solid particles and the liquid phase, high capacity, and an adjustable voidage in the fluidized bed obtained by changing the velocity of the fluid thus changing the void fraction due to bed expansion.
  • the inverse fluidization apparatus and method of the invention can be operated in a continuous mode, with contaminant-saturated particles being collected downstream the column and fresh particles being added at the top, or anywhere else along the fluidization column.
  • Beds of the invention can provide more homogeneity in removal of contaminants such as oils than is seen with many packed bed arrangements where the flow often is not well distributed throughout the bed.
  • the downward flow arrangement of inverse fluidization columns described herein promotes coalescence of the droplets of an immiscible contaminant such as oil, favoring higher removal efficiency.
  • hydrophobic silica aerogels are particularly well suited for the removal of immiscible organic compounds, e.g., oils, from water. Combining the properties of these materials with the advantageous properties of inverse fluidization can result in large capacity and high removal efficiency, e.g., as high as 99.9%, depending on the operating conditions.
  • Oil-contaminated streams can be purified to levels of 1 part per million (PPM) or lower.
  • FIG. 1 is a schematic representation of droplet size classification and conventional methods that can be used to remove them.
  • FIG. 2A is a photograph showing oily water before contact with a packed bed of Nanogel® particles.
  • FIG. 2B is a photograph showing purified water after the oily was contacted with the packed bed of Nanogel® particles.
  • FIG. 3 is a schematic diagram of inverse fluidization.
  • FIG. 4 is a schematic diagram of an arrangement that can be used to conduct the method of the invention.
  • FIG. 5 is a plot showing the relationship between the oil concentration in water and the Chemical Oxygen Demand (COD) as measured by the HACH method with the Colorimeter.
  • FIG. 6A is a photograph of an inverse fluidized bed of 500-850 microns Nanogel® particles (sieved).
  • FIG. 6B is a photograph of an inverse fluidized bed of 2.3 mm Nanogel® particles (un-sieved).
  • FIGS. 7A through 7C are series of plots showing pressure drop across inversely fluidized beds of translucent Nanogel® particles as a function of fluid velocity.
  • FIGS. 8A through 8C are series of plots of bed expansion as a function of fluid velocity.
  • FIG. 9 is a plot of concentration, measured by COD, as a function of time upstream (straight line) and downstream (diamonds) in an inverse fluidized bed of 56 g of Nanogel®. Bed expansion (squares) as a function of time also is shown.
  • the size range of the aerogel granules was between 0.5 to 0.85 mm.
  • the fluid velocity was 0.0107 cm/s.
  • Upstream oil concentration was about 450 mg of oil/l of water.
  • FIG. 10 is a plot of chemical oxygen demand (COD) and inverse fluidized bed expansion (squares) as a function of time of 108 grams of translucent Nanogel® granules with sizes between 0.5 to 0.85 mm during removal of oil from water (0.47 g of oil/kg of water and 0.0102 m/s fluid velocity).
  • COD chemical oxygen demand
  • squares inverse fluidized bed expansion
  • FIG. 11 is a plot of chemical oxygen demand (COD) and inverse fluidized bed expansion (squares) as a function of time of 56 grams of opaque Nanogel® granules with sizes between 0.5 to 0.85 mm during removal of oil from water (0.18 g of oil/kg of water and fluid velocity of 0.0305 m/s).
  • COD chemical oxygen demand
  • squares inverse fluidized bed expansion
  • FIG. 12 is a plot of chemical oxygen demand (COD) and inverse fluidized bed expansion (squares) as a function of time of 100 grams of opaque Nanogel® granules with sizes between 0.5 to 0.85 mm during removal of oil from water (0.18 g of oil/kg of water and fluid velocity of 0.0305 m/s).
  • COD chemical oxygen demand
  • squares inverse fluidized bed expansion
  • FIG. 13 is plot of pressure drop across the inversely fluidized beds of aerogel during the removal of oil corresponding to FIGS. 11 and 12 .
  • Superficial flow velocity was kept constant at 0.0305 m/s.
  • the invention generally relates to removing contaminants present in a fluid system and can be carried out for health or safety reasons, to meet environmental requirements, to clean recyclable or discharged streams in refineries, industrial or commercial applications, or for other reasons.
  • fluid generally refers to liquids, gases, including vapors, supercritical fluids, viscous fluids and so forth.
  • fluid systems that can be purified by practicing the invention include liquid systems and supercritical fluid systems.
  • the system is an aqueous waste stream.
  • Non-aqueous systems including carriers such as organic media, e.g., organic solvents, supercritical carbon dioxide and many others also can be purified.
  • the system includes a contaminant.
  • contaminant refers to a material, e.g., an impurity, or combination of materials not desired in the fluid system.
  • the contaminant is a liquid.
  • examples include organic materials e.g., oils, such as vegetable oil, animal oil, motor oil, crude oil, synthetic oil, and other organic compounds, e.g., hydrocarbons, such as reagents or solvents, e.g., cyclohexane, toluene, benzene, ethanol, trichloroethylene, and so forth.
  • the liquid contaminant can be miscible or immiscible in the carrier.
  • one or more water-miscible organic compound(s) can be removed from an aqueous system.
  • an aqueous system can include a water-immiscible hydrocarbon.
  • Solid contaminants e.g., metals, contaminants such as inorganic materials, biological compounds, organometallics and so forth also could be removed by practicing implementations of the invention.
  • More than one type of contaminant can be removed.
  • a contaminant that includes a solvent e.g., cyclohexane, toluene, benzene, ethanol, trichloroethylene, in combination with an oil can be removed from an aqueous system.
  • a solvent e.g., cyclohexane, toluene, benzene, ethanol, trichloroethylene
  • the particle, e.g., droplet, size of the contaminant depends on the application. It can be, for example, in the range of from about 1 micrometers (microns or ⁇ m) to about 150 microns or as large as several millimeters. In some embodiments, the contaminant has a particle size, in the range of from about 1 to about 10000 microns, preferably in the range of from about 5 to about 150 microns.
  • the fluid phase system is contacted with an inversely fluidized material.
  • the material is porous, e.g., microporous or nanoporous and in particulate form.
  • microporous refers to materials having pores that are about 1 micron and larger; the term “nanoporous” refers to materials having pores that are smaller than about 1 micron, preferably less than about 0.1 microns. Pore size can be determined by methods known in the art, such as mercury intrusion porosimetry, or microscopy. Preferably the pores are interconnected giving rise to open type porosity.
  • the porous, e.g., nanoporous material can be an oxide of a metal, such as, for instance, silicon, aluminum, zirconium, titanium, hafnium, vanadium, yttrium and others, and/or mixtures thereof. In some applications, microporous materials also could be utilized.
  • a metal such as, for instance, silicon, aluminum, zirconium, titanium, hafnium, vanadium, yttrium and others, and/or mixtures thereof.
  • microporous materials also could be utilized.
  • Materials that are particularly preferred include aerogels and/or xerogels.
  • Aerogels are low density porous solids that have a gas rather than a liquid as a dispersant. Generally, they are produced by removing pore liquid from a wet gel. However, the drying process can be complicated by capillary forces in the gel pores, which can give rise to gel shrinkage or densification. In one manufacturing approach, collapse of the three dimensional structure is essentially eliminated by using supercritical drying.
  • a wet gel also can be dried using an ambient pressure, also referred to as non-supercritical drying process. When applied, for instance, to a silica-based wet gel, surface modification, e.g., end-capping, carried out prior to drying, prevents permanent shrinkage in the dried product. The gel can still shrinks during drying but springs back recovering its former porosity.
  • xerogel also is obtained from wet gels from which the liquid has been removed.
  • the term often designates a dry gel compressed by capillary forces during drying, characterized by permanent changes and collapse of the solid network.
  • Aerogels typically have low bulk densities (about 0.15 g/cm 3 or less, preferably about 0.03 to 0.3 g/cm 3 ), very high surface areas (generally from about 300 to about 1,000 square meter per gram (m 2 /g) and higher, preferably from about 600 to about 1000 m 2 /g), high porosity (about 90% and greater, preferably greater than about 95%), and a relatively large pore volume (about 3 milliliter per gram (mL/g), preferably about 3.5 mL/g and higher). Aerogels can have a nanoporous structure with pores smaller than 1 micron ( ⁇ m). Often, aerogels have a mean pore diameter of about 20 nanometers (nm).
  • Aerogels can be nearly transparent or translucent, scattering blue light, or can be opaque.
  • Aerogels based on oxides of metals other than silicon e.g., aluminum, zirconium, titanium, hafnium, vanadium, yttrium and others, or mixtures thereof can be utilized as well.
  • organic aerogels e.g., resorcinol or melamine combined with formaldehyde, dendredic polymers, and so forth, and the invention also could be practiced using these materials.
  • the material, e.g., aerogel employed is hydrophobic.
  • hydrophobic and hydrophobized refer to partially as well as to completely hydrophobized aerogel.
  • the hydrophobicity of a partially hydrophobized material such as aerogel can be further increased.
  • completely hydrophobized materials, e.g., aerogels a maximum degree of coverage is reached and essentially all chemically attainable groups are modified.
  • Hydrophobicity can be determined by methods known in the art, such as, for example, contact angle measurements or by methanol (MeOH) wettability.
  • MeOH methanol
  • Hydrophobic materials such as hydrophobic aerogels can be produced by using hydrophobizing agents, e.g., silylating agents, halogen- and in particular fluorine-containing compounds such as fluorine-containing alkoxysilanes or alkoxysiloxanes, e.g., trifluoropropyltrimethoxysilane (TFPTMOS), and other hydrophobizing compounds known in the art. Hydrophobizing agents can be used during the formation of aerogels and/or in subsequent processing steps, e.g., surface treatment.
  • hydrophobizing agents e.g., silylating agents, halogen- and in particular fluorine-containing compounds such as fluorine-containing alkoxysilanes or alkoxysiloxanes, e.g., trifluoropropyltrimethoxysilane (TFPTMOS), and other hydrophobizing compounds known in the art. Hydrophobizing agents can be used during the formation of aerogels and/or
  • Silylating compounds such as, for instance, silanes, halosilanes, haloalkylsilanes, alkoxysilanes, alkoxyalkylsilanes, alkoxyhalosilanes, disiloxanes, disilazanes and others are preferred.
  • silylating agents include, but are not limited to diethyldichlorosilane, allylmethyldichlorosilane, ethylphenyldichlorosilane, phenylethyldiethoxysilane, trimethylalkoxysilanes, e.g., trimethylbutoxysilane, 3,3,3-trifluoropropylmethyldichlorosilane, symdiphenyltetramethyldisiloxane, trivinyltrimethylcyclotrisiloxane, hexaethyldisiloxane, pentylmethyldichlorosilane, divinyldipropoxysilane, vinyldimethylchlorosilane, vinylmethyldichlorosilane, vinyldimethylmethoxysilane, trimethylchlorosilane, hexamethyldisiloxane, hexenylmethyldichlorosilane,
  • the porous material can include one or more additives, such as fibers, opacifiers, color pigments, dyes and mixtures thereof.
  • a nanoporous material which is a silica aerogel can contain additives such fibers and/or one or more metals or compounds thereof. Specific examples include aluminum, tin, titanium, zirconium or other non-siliceous metals, and oxides thereof.
  • suitable opacifiers include carbon black, titanium dioxide, zirconium silicate, and mixtures thereof. While any appropriate loading of opacifier may be used, preferred loadings for the opacifier are between 1 vol. % and 50 vol. %).
  • the particulate porous material can be produced in granular, pellet, bead, powder, or other particulate form and in any particle size suitable for an intended application.
  • the particles can be within the range of from about 0.01 microns to about 10.0 millimeters (mm) and preferably have a mean particle size in the range of 0.3 to 3.0 mm.
  • Nanogel® granules have high surface area, are more than about 90% porous and are available in a particle size ranging, for instance, from about 8 microns ( ⁇ m) to about 10 mm.
  • Contaminants can be removed using combinations of materials, for instance, combinations of materials such as those disclosed in U.S. Pat. No. 6,709,600 B2 issued to Hrubesh et al. on Mar. 23, 2004, the teachings of which are incorporated herein by reference in their entirety.
  • aerogel granules can be used in conjunction with activated carbon to remove miscible and immiscible hydrocarbons from water.
  • materials described above, and in particular hydrophobic silica aerogel are used to remove organic compounds from an aqueous system.
  • FIG. 2A and FIG. 2B A qualitative assessment regarding the performance Nanogel® particles in purifying an oil-water mixture is shown in the photographs ( FIG. 2A and FIG. 2B ), where FIG. 2A shows oily water before contact with a packed bed of Nanogel® particles and FIG. 2B shows purified water after the oily water was contacted with the packed bed of Nanogel® particles.
  • Aerogel and/or other materials that have a density lower than that of the fluid phase system being purified can remove contaminants by inverse fluidization, a process in which solid particles are dispersed in a fluid, when the density of the particulate material is less than the density of the fluid.
  • the difference between the density of the fluidizing fluid, e.g., a wastewater stream being purified, and the solid material employed to effect the purification is at least about 0.1 g/cm 3 .
  • the solid material used preferably has a density that is less than about 0.8 g/cm 3 , more preferably a density that is less than about 0.1 g/cm 3 .
  • the material has a density within the range of from about 0.01 to about 0.8 g/cm 3 .
  • FIG. 3 Shown in FIG. 3 is a schematic diagram of liquid solid inverse fluidization.
  • the liquid flow represented by arrows L is in the direction of gravity, downwards, and the bed expands from the top of the column 20 towards the bottom.
  • Full fluidization of the bed is reached when there is a balance between the forces acting on the particles, e.g., particle 22 , specifically: drag (arrow D), gravity (arrow G), and buoyancy (arrow B), forces at the minimum fluidization velocity.
  • Inverse fluidization can be conducted in a housing, e.g., column, which can be constructed from a suitable material such as a plastic material, e.g., acrylic, glass, metal, e.g., aluminum, steel, or from another suitable material.
  • a fluidization bed includes nanoporous material having a density lower than that of the fluidizing medium.
  • the inverse fluidization apparatus of the invention is configured for continuous operation. Since with time solid, e.g. aerogel, particles saturated with contaminant become heavy, they can be collected downstream of the fluidized bed system. Fresh particles can be added at the top or anywhere else along the fluidization column.
  • the size of granules used in the inverse fluidized beds of the invention can depend on factors such as specific application, height of the fluidized bed and so forth. For instance, if a design requires a bed that is relatively short, e.g., a few feet, then a small granule size e.g., less than 1 mm, may be preferred. Larger particle sizes can be used in taller fluidized bed. While small granules provide better removal efficiency they also tend to require operation at low superficial velocities.
  • the aerogel particle size is greater than 0.5 mm. For instance, the particle size can be, but is not limited to be within the range of from about 0.5 to about 2.3 mm. Larger aerogel particles, e.g., 10 mm, also can be used, for instance in scale-up applications, and/or when using larger fluid velocities. Smaller particle sizes also can be selected.
  • Inverse fluidization employing a material such an aerogel can be operated at a temperature that allows for the existence of the liquid phase. In case of water, from 32° F. up to close to 212° F., preferably in the range of from about 40° F. to about 150° F.
  • Practicing aspects of the invention can purify oil bearing waste water streams to a level of 1 PPM or lower.
  • Inverse fluidization can be used in combination with other purification techniques and/or devices, for example with packed bed filters, regular fluidized beds, coalescing elements, API separators, ultrafiltration systems, reverse osmosis, activated carbon adsorbers and so forth.
  • Systems and processes can be designed to include a bed and/or method such as described herein.
  • inverse fluidization of aerogel particles is combined with one or more other techniques for purifying fluid streams that contain contaminants having relatively large droplet sizes.
  • inverse fluidization of aerogel particles is used upstream of an activated carbon filter to remove water-miscible or water-immiscible hydrocarbons from water.
  • a fluid stream e.g., wastewater, containing solid as well as liquid, e.g., oil, contaminants is purified by removing solid contaminants using a suitable technique, optionally followed by a technique suitable for removal of larger droplets, followed by an inverse fluidization process or apparatus such as described herein for removing remaining droplets, to produce a purified stream.
  • the aerogel employed was Nanogel® obtained from Cabot Corporation, Billerica, Mass. Two of the granule sizes used were: (A) 2.3 mm sieved granules having a particle size range between 1.7 and 2.3 mm; and (B) 500-850 ⁇ m, sieved granules. Experiments also were conducted using un-sieved 2.3 mm granules, which included granules in the range of 0.5 up to 2.3 mm. Translucent specifications are labeled herein as TLD and opaque specifications as OGD. Numbers following the TLD and OGD specifications are particle size descriptors.
  • FIG. 4 A schematic diagram of the experimental setup including an inverse fluidization bed, in which, as discussed above, contaminated water flows downwards inside the column, is shown in FIG. 4 .
  • FIG. 4 Shown in FIG. 4 is an apparatus 40 including inverse fluidization column 42 , water supply 44 , metering pump 46 , static mixer 48 , sampling points 52 and 54 , filter 56 , drain 58 , flow meters 62 and 64 and pressure gauge 66 .
  • flow meters 62 and 64 one provided for low range flows and the other for larger flows, measured flow of water.
  • Oil, as well as any other immiscible liquid or solution, were added to the water in a controlled manner by metering pump 46 .
  • the added oil or solution was mixed with the water by passage through static mixer 48 .
  • the pressure in the system was measured at this point (by pressure gauge 56 ) and was kept constant during the entire experiment, and also for different runs.
  • the pressure drop across the bed was measured by a differential pressure transmitter with a range of 0 to 2 psid.
  • a sample of the oil-contaminated water was drawn for analysis, e.g., at sampling point 52 , before entering fluidization column 42 .
  • a second sample of water was taken after passing through the inverse fluidized bed, e.g., at sampling point 54 .
  • HACH colorimeter
  • FIG. 6A is a photograph of inverse fluidized bed of 500-850 microns Nanogel® particles (sieved).
  • FIG. 6B is a photograph of inverse fluidized bed of 2.3 mm Nanogel® particles (un-sieved).
  • the inversely fluidized bed pressure drop and bed expansion data were collected as a function of fluid velocity; these data are shown in FIGS. 7A through 7C and 8 A through 8 C, respectively.
  • the data show typical behavior of liquid-solid fluidized beds characterized by a proportional increase in the bed pressure drop at fluid velocities below minimum fluidization velocity, a pressure drop plateau during full fluidization, a minimum fluidization velocity dependant on particle size, a pressure drop dependant on the amount of particles and a bed expansion that starts at the minimum fluidization velocity.
  • FIGS. 7A , 7 B and 7 C indicate that the pressure drop will depend on the amount of powder that is inversely fluidized. This behavior is quite different from that typically observed in a packed bed where a large pressure drop is obtained even with a small amount of granules when there is a large liquid flow passing through it. For filter beds, a maximum differential pressure drop of 10 psid generally is acceptable during operation; a higher pressure drop leads to excessive energy costs.
  • the bed starts to expand at full fluidization, which occurs at fluid velocity values larger than the minimum fluidization velocity (shown by the arrows).
  • the increase in bed height means that the void fraction of the fluidized bed, which has strong effects on the contaminant removal rate, is increasing.
  • the voidage of the bed preferably is adjusted in order to expose each individual Nanogel® particle to the contaminant, e.g., oil in the water, but without allowing oil droplets to pass through the fluidized bed, a condition that can occur at high fluid velocities and large values of the void fraction for relatively short beds.
  • the oil will be adsorbed more homogenously in an inverse fluidized bed than in a packed bed where, in some cases, the flow is not well distributed within the void volume of the bed.
  • Nanogel® granules with sizes from 500 to 850 microns were used to adsorb oil from water.
  • the flow velocity was about 1.07 cm/s.
  • the concentration of oil upstream the fluidized bed was about 450 mg of oil/l of water.
  • the inverse fluidized bed of Nanogel® is very effective in removing oil from water.
  • COD concentration which implies a more than 90% removal rate; other experiments have shown removal efficiencies of 99%, and higher.
  • the bed height (squares) was also monitored during the removal of oil from water by the inverse fluidized bed as shown in FIG. 9 . It can be clearly seen that the bed expands as a consequence of the saturation of some of the Nanogel® granules with oil. Since they become heavier, they tend to move towards the bottom of the column, increasing the bed height of the fluidized bed.
  • the adsorption capacity of the Nanogel® was quite large since 56 grams of the material adsorbed 420 grams of oil (as estimated by the injection of oil, 0.105 kg/h, during 4 hours). This means a 7.5 by weight ratio of oil adsorbed with respect to the amount of Nanogel®.
  • the pressure drop of the inversely fluidized bed was monitored during the removal of oil from water and the maximum pressure drop was about 700 Pa (0.1 psi), which is far below the pressure drop of a packed bed containing a similar amount of granules.
  • FIG. 9 there is a change in slope (inflection point) with time; the pressure drop increases as oil is injected into the fluidizing water but then decreases as Nanogel® granules become heavier reducing their buoyancy and the drag force needed to fluidize them. During the process, granules are also being entrained from the fluidization column reducing the pressure drop even further.
  • Nanogel® granules with sizes from 500 to 850 microns were used to adsorb oil from water.
  • the flow velocity was about 1.02 cm/s.
  • the concentration of oil upstream the fluidized bed was about 470 mg of oil per kg (liter) of water.
  • the inverse fluidized bed of Nanogel® was very effective on removing oil from water with a reduction in COD concentration from 1400 mg/l down to 40 mg/l, which implies a 97% removal.
  • the bed height was also monitored during the removal of oil from water by the inverse fluidized bed as also shown in FIG. 10 . It can be clearly seen that the bed reduces as a consequence of the saturation of some of the Nanogel® granules with oil. In this case, because of the initial taller height of the fluidized bed (more particles were used thus increasing the initial bed height), there was an oil concentration gradient, with more oil at the top. This gradient makes particles at the top saturate faster than particles at other locations in the fluidized bed. After saturation, these particles become heavier and are entrained by the flow leading to a reduction in the bed expansion. Thus a continuous process can easily be designed by feeding clean granules into the system at the top, while granules saturated with oil leave the column at the bottom.
  • FIG. 11 shows the COD levels and the bed expansion of 56 grams of small aerogel granules. It can be seen that there is a significant bed expansion from 40 to 50 cm, indicating a CSTR-type of mixing where most of the granules saturate simultaneously.
  • FIG. 12 shows COD levels and bed expansion for 100 grams of small aerogel granules exposed to the same concentration of oil and operating conditions as in the experiment using 56 grams described in FIG. 11 .
  • FIG. 13 shows the differential pressure drop across the inverse fluidized beds described by FIG. 11 and FIG. 12 during oil removal; as expected, the figure shows that the pressure drop is proportional to the amount of fluidized powder in the bed. In both cases, the pressure drop across the bed of granules does not plateau, indicating that the granules did not fully saturate.
  • pressure drop observed with inverse fluidized beds described herein is low, e.g., about 0.2 psid, and does not build up with use.
  • the initial pressure drop across the fluidized bed of granules is only dependant on the amount of aerogels used, the density of the aerogels and the cross sectional area of the column.
  • the pressure drop increases initially, due to the buoyancy of the oil droplets, then decreases due to the reduction in the buoyancy of the aerogel granules as oil is adsorbed into them increasing their weight.
  • Nanogel® particles the bed exhibits very good mixing between the aerogel and a liquid phase system, e.g., aqueous system.

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US20130200004A1 (en) * 2010-06-03 2013-08-08 Newcastle Innovation Limited Method and apparatus for separating low density particles from feed slurries
US9278314B2 (en) 2012-04-11 2016-03-08 ADA-ES, Inc. Method and system to reclaim functional sites on a sorbent contaminated by heat stable salts
CN105457339A (zh) * 2014-09-10 2016-04-06 中国科学院化学研究所 油水分离方法及装置
US9352270B2 (en) 2011-04-11 2016-05-31 ADA-ES, Inc. Fluidized bed and method and system for gas component capture
CN109925746A (zh) * 2019-04-02 2019-06-25 福建农林大学 一种油水分离用自清洁藻酸盐基复合二氧化钛气凝胶材料及其制备方法
US10808183B2 (en) 2012-09-12 2020-10-20 The University Of Wyoming Research Corporation Continuous destabilization of emulsions
CN113884415A (zh) * 2021-09-28 2022-01-04 东北大学 一种多孔非球形颗粒曳力系数的测量装置

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CN104383719B (zh) * 2014-12-01 2016-04-06 东北石油大学 一种倒置流化床油滴捕获器
CN106242102A (zh) * 2016-04-21 2016-12-21 浙江海洋学院 一种工业废水净化处理方法
KR101661516B1 (ko) * 2016-07-11 2016-09-30 필터로직 주식회사 복합 필터 및 그 제조방법
CN110078164A (zh) * 2019-05-06 2019-08-02 东北石油大学 二级串联流化床油水分离器

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US10808183B2 (en) 2012-09-12 2020-10-20 The University Of Wyoming Research Corporation Continuous destabilization of emulsions
CN105457339A (zh) * 2014-09-10 2016-04-06 中国科学院化学研究所 油水分离方法及装置
CN109925746A (zh) * 2019-04-02 2019-06-25 福建农林大学 一种油水分离用自清洁藻酸盐基复合二氧化钛气凝胶材料及其制备方法
CN113884415A (zh) * 2021-09-28 2022-01-04 东北大学 一种多孔非球形颗粒曳力系数的测量装置

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