[go: up one dir, main page]

US20060086834A1 - System and method for nanoparticle and nanoagglomerate fluidization - Google Patents

System and method for nanoparticle and nanoagglomerate fluidization Download PDF

Info

Publication number
US20060086834A1
US20060086834A1 US10/900,868 US90086804A US2006086834A1 US 20060086834 A1 US20060086834 A1 US 20060086834A1 US 90086804 A US90086804 A US 90086804A US 2006086834 A1 US2006086834 A1 US 2006086834A1
Authority
US
United States
Prior art keywords
fluidization
force
bed
nanoparticles
nanoparticle
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.)
Abandoned
Application number
US10/900,868
Other languages
English (en)
Inventor
Robert Pfeffer
Caroline Nam
Rajesh Dave
Guangliang Liu
Jose Quevedo
Qun Yu
Chao Zhu
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.)
New Jersey Institute of Technology
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to US10/900,868 priority Critical patent/US20060086834A1/en
Assigned to NEW JERSEY INSTITUTE OF TECHNOLOGY reassignment NEW JERSEY INSTITUTE OF TECHNOLOGY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YU, QUN, ZHU, CHAO, PFEFFER, ROBERT, DAVE, RAJESH N., LIU, GUANGLIANG, NAM, CAROLINE H., QUEVEDO, JOSE A.
Publication of US20060086834A1 publication Critical patent/US20060086834A1/en
Priority to US11/605,176 priority patent/US7658340B2/en
Abandoned legal-status Critical Current

Links

Images

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
    • 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
    • B01J8/1872—Details of the fluidised bed reactor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F31/00—Mixers with shaking, oscillating, or vibrating mechanisms
    • B01F31/80—Mixing by means of high-frequency vibrations above one kHz, e.g. ultrasonic vibrations
    • B01F31/86—Mixing by means of high-frequency vibrations above one kHz, e.g. ultrasonic vibrations with vibration of the receptacle or part of it
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/40—Mixers using gas or liquid agitation, e.g. with air supply tubes
    • B01F33/406—Mixers using gas or liquid agitation, e.g. with air supply tubes in receptacles with gas supply only at the bottom
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/45—Magnetic mixers; Mixers with magnetically driven stirrers
    • B01F33/451—Magnetic mixers; Mixers with magnetically driven stirrers wherein the mixture is directly exposed to an electromagnetic field without use of a stirrer, e.g. for material comprising ferromagnetic particles or for molten 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
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/10—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing sonic or ultrasonic vibrations
    • 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
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/40—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed subjected to vibrations or pulsations
    • 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
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/42—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed subjected to electric current or to radiations this sub-group includes the fluidised bed subjected to electric or magnetic fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y15/00—Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00654—Controlling the process by measures relating to the particulate material
    • B01J2208/00681—Agglomeration

Definitions

  • the present disclosure relates to system(s) and method(s)/process(es) for fluidizing nanoparticles and nanoagglomerates. More particularly, the present disclosure is directed to systems and methods/processes for fluidizing nanoparticles and nanoagglomerates utilizing a fluidizing gas with one or more external forces, e.g., a vibration force, a magnetic force, an acoustic force, a rotational force and combinations thereof.
  • Advantageous results are achieved, at least in part, by establishing a desired nanoparticle/nanoagglomerate particle size distribution within the system and substantially maintaining such distribution as the system achieves and maintains a fluidized state.
  • Fluidization is a widely used process in several industries to achieve continuous powder handling ability, particle mixing, and desirable levels of solid-gas contact.
  • gas fluidization is a process in which solid particles are transformed into a fluid-like state through suspension in a gas.
  • Gas fluidization is one of the best techniques available to disperse and process powders belonging to the Geldart group A and B classifications. Fluidization processes can be used to achieve high heat and mass transfer and reaction rates. Gas fluidization of small solid particles has been widely used in a variety of industrial applications because of its unusual capability of continuous powder handling, good mixing, large gas-solid contact area and high rates of heat and mass transfer.
  • nanostructured materials are effective for the manufacture of drugs, cosmetics, foods, plastics, catalysts, high-strength or corrosion resistant materials, energetic and bio materials, and in mechatronics and micro-electro-mechanical systems (MEMS).
  • MEMS micro-electro-mechanical systems
  • processing technologies which can handle large quantities of nanosized particles, e.g., mixing, transporting, modifying the surface properties (coating) and downstream processing of nanoparticles to form nano-composites, are desirable. But before processing of nanostructured materials can take place, the nanosized particles have to be well dispersed.
  • nanoparticles are found to be in the form of large-sized agglomerates (rather than as individual nano-sized particles) when packed together in a gaseous medium.
  • gas fluidization of nanoparticles generally refers to the fluidization of nanoparticle agglomerates.
  • the size of the fluidized nanoparticle agglomerates is typically from about 100 to 700 ⁇ m, while the primary particle size ranges from 7 to 500 nm.
  • a typical nanoparticle agglomerate size distribution (by weight percentage) for a commercially available product is shown in FIG. 1 . The data reflected in FIG.
  • ABSF agglomerate bubbling fluidization
  • nanoparticle agglomerates can also be fluidized in a rotating or centrifugal fluidized bed [See, Matsuda et al., Particle and bubble behavior in ultrafine particle fluidization with high G, Fluidization X, Eng. Found, 2001, 501-508; Matsuda et al., Modeling for size reduction of agglomerates in nanoparticle fluidization , AIChE 2002 Annual Meeting, Nov. 3-8, 2002, Indianapolis, Ind., 138e], where the centrifugal force acting on the agglomerates can be set much higher than gravity.
  • U.S. Pat. No. 4,720,025 to Tatevosian discloses a technique that utilizes an alternating magnetic field along with magnetic particles to loosen up material at the bottom of a hopper for feeding into a certain operation. However, the disclosed technique does not include loosening up cohesive materials for application in a fluidized bed.
  • U.S. Pat. No. 6,471,096 to Dave discloses the use of alternating magnetic field along with permanent magnets to produce controllable discharge of cohesive powders from a container, but does not provide for fluidization of nano-powders.
  • U.S. Pat. No. 3,848,363 to Lovness et al. discloses the use of magnetic force to move particles in a predetermined area, but again does not provide for any application to fluidization.
  • the fluidization of larger particle mixtures of millimeter size (Geldart group D particles), such as iron-copper shot of 0.935 to 1.416 mm in diameter is described in [W. Y. Wu, A. Navada, S. C. Saxena, Hydrodynamic characteristics of a magnetically stabilized air fluidized bed of an admixture of magnetic and non - magnetic particles, Powder Technology, 90(1997) 39-46] and [W. Y.
  • a magnetically assisted impaction coating (MAIC) process may be an effective method for providing the extra force needed to break up the dense phase or layer of particles.
  • the MAIC process has been successfully used as a dry coating method.
  • the MAIC process utilizes an oscillating magnetic field to accelerate magnetic particles thereby providing collisions between particles and the walls of the apparatus.
  • a need remains for systems and methods/processes that provide for effective fluidization of nanoparticles.
  • a further need remains for systems and processes that uniformly fluidize a bed of nanoparticles.
  • systems and processes for nanoparticle fluidization that function without forming a dense layer of agglomerates.
  • fluidization systems and processes that minimize powder loss while fluidizing nanoparticles are needed. It is a further need to determine characteristics of nanoparticle agglomerates and to use such characteristics in enhancing fluidization effectiveness.
  • the present disclosure provides an improved system and method/process for fluidizing nanoparticles and nanoagglomerates that includes exposing nanoparticles and nanoagglomerates to a combined flow of fluidizing gas and at least one additional force.
  • the additional force may be supplied from a variety of sources and may take a variety of forms, e.g., a vibration force, a magnetic force, an acoustic force, a rotational/centrifugal force and/or a combination thereof.
  • the disclosed system and method utilizes a fluidizing gas (e.g., air, N 2 , He, Ar, O 2 and/or combinations thereof or other fluidizing gas or gases) that may be combined with an appropriate amount of magnetic energy, mechanical energy, acoustic energy and/or rotational/centrifugal energy to enhance fluidization by disrupting interparticle forces.
  • a fluidizing gas e.g., air, N 2 , He, Ar, O 2 and/or combinations thereof or other fluidizing gas or gases
  • the nanoparticles/nanoagglomerates treated according to the disclosed system/method can form highly porous agglomerates in the size range of approximately 200-400 microns.
  • Enhanced fluidization of nanoagglomerate/nanoparticles systems is achieved according to the systems and methods/processes of the present disclosure, at least in part, by establishing a desired nanoparticles/nanoagglomerates particle size distribution within the system and substantially maintaining such distribution as the system achieves and maintains a fluidized state.
  • a desired particle size distribution is established by introducing an external energy stimulus at a level effective to overcome the inter-particle forces associated with nanoparticles/nanoagglomerates systems and to thereby shift the particle size distribution into a range that supports and/or evidences enhanced fluidization.
  • a desired particle size distribution may be effected through a pre-treatment step, e.g., a sieving step.
  • enhanced fluidization is reflected by at least one of the following performance-related attributes: reduced levels of bubbles within the fluidized system, reduced gas bypass relative to the fluidized bed, smooth fluidization behavior, reduced elutriation, a high level of bed expansion, reduced gas velocity levels to achieve desired fluidization performance, and/or enhanced control of agglomerate size/distribution.
  • modification of an initial particle size distribution e.g., an “as received” particle size distribution
  • a desired particle size distribution range allows the disclosed fluidization system to achieve and maintain desired fluidization conditions.
  • an external energy source and/or a pre-treatment step as described in greater detail herein, the disclosed fluidization system advantageously establishes a state of dynamic equilibrium, wherein nanoagglomerates are formed, broken and randomly reformed, in an expanded fluidized bed.
  • the dynamic equilibrium established according to the disclosed system/method offers many advantages, including facilitating substantially homogenous coating and/or treatment of nanoparticles/nanoagglomerates.
  • Exemplary fluidization apparatus includes a gas supply source and at least one energy source for generating and supplying one or more of the energies disclosed herein, e.g., a vibrating source, a source for inducing a magnetic field, an acoustic source, and/or a source of centrifugal and/or rotational force.
  • Other features that may be associated with the fluidization apparatus of the present disclosure include a gauge for measuring gas flow, a fluidization chamber, a distributor, gas dispersion elements (e.g., glass beads), filter(s), viewing device(s) and/or a vent.
  • nanoparticles and nanoagglomerates advantageous results are achieved in fluidizing nanoparticles and nanoagglomerates across a broad range of applications, e.g., applications that involve the manufacture of drugs, cosmetics, foods, plastics, catalysts, high-strength or corrosion resistant materials, energetic and bio materials, and in mechatronics and micro-electro-mechanical systems. More particularly, effective dispersion of nanoparticles and nanoagglomerates is achieved according to the present disclosure, thereby facilitating a host of nanoparticle-related processing regimens, e.g., mixing, transporting, surface property modifications (e.g., coating), and/or downstream processing to form nano-composites.
  • nanoparticle-related processing regimens e.g., mixing, transporting, surface property modifications (e.g., coating), and/or downstream processing to form nano-composites.
  • a bed may be expanded to more than double its original chamber or bed height with hardly any elutriation of the nanoparticles.
  • the system and method of the present disclosure advantageously provides for greater control of the fluidizing process, despite a high degree of mixing, thereby reducing powder loss relative to conventional fluidized chambers or beds.
  • the supply of energy or force e.g., vibration
  • the supply of energy or force in accordance with one aspect of the present disclosure may advantageously only be utilized initially to aid in the break-up of interparticle forces and form nanoagglomerates, so that the chamber or bed can be effectively fluidized. Thereafter, such energy/force may be discontinued, as desired by the system operator or applicable control systems.
  • some powder beds under flow of fluidizing gas and external energy supply, e.g., vibration, may be divided into two distinct regimes, a dense immobile phase and a smoothly fluidized mobile phase above the dense immobile phase.
  • the dense immobile phase may be substantially eliminated according to the present disclosure by adding heavy permanent magnetic particles to the mix, preferably near the dense immobile phase, and then exciting the magnetic particles via a magnetic field, e.g., an oscillating magnetic field.
  • a magnetic field e.g., an oscillating magnetic field.
  • an external force e.g., magnetic, acoustic, centrifugal/rotational and/or vibration excitation forces, advantageously provides for better control of the degree of particle movement. Combining such force(s) with fluidizing gas flow advantageously achieves excellent mixing, smooth fluidization, and high bed expansion with very little particle loss in a safe and inexpensive manner.
  • the systems and methods of the present disclosure are advantageously well suited for fluidization of nanoparticles (extreme Geldart C powders), utilizing one or more external forces and aeration (or a flow of another gas) to overcome fluidization difficulties often associated with cohesive particles (e.g., channeling, spouting, plug formation) and to thereby advantageously achieve vigorous fluidization in any of a variety of differently shaped fluidization chambers or beds (e.g., tubular and/or rectangular fluidization beds).
  • fluidization characteristics of a variety of different nanoparticles are provided and such fluidization characteristics are advantageously correlated with macroscopic fluidization behavior (APF or ABF) of the nanoagglomerates.
  • APF macroscopic fluidization behavior
  • the properties of primary nanoparticles were established in a conventional gravity-driven fluidized bed without any additional external forces present.
  • a simple and effective method for estimating the average size of agglomerates and bed voidage around the agglomerates is provided.
  • the estimation methodology can then be used in models to determine the minimum fluidization velocity, pressure drop and other pertinent variables of the fluidization process, and to determine the external force(s) required to establish a desired particle size distribution to achieve and support efficacious nanoparticle/nanoagglomerate fluidization, as described herein.
  • FIG. 1 is a plot of particle size distribution for a commercially available “as received” silica product
  • FIG. 2 is a schematic drawing of an exemplary fluidization apparatus in accordance with an illustrative aspect of the present disclosure
  • FIG. 3 is a plot showing bed height as a function of time with variations in aeration and vibration conditions according to an exemplary embodiment of the present disclosure
  • FIGS. 4 ( a ) and 4 ( b ) are plots showing bed expansion ratios as a function of time for different operating conditions according to an exemplary embodiment of the present disclosure
  • FIG. 5 is a plot showing pressure drop as a function of superficial air velocity under specified operating conditions according to an exemplary embodiment of the present disclosure
  • FIGS. 6 ( a ) and 6 ( b ) are photographic images of fluidization performance with and without the introduction of a magnetic field
  • FIG. 7 is a plot showing bed expansion ratio and pressure drop for fluidization systems with and without magnetic excitation
  • FIG. 8 is a plot showing bed expansion ratio and pressure drop for conventional fluidization of an 80/20 mixture before and after magnetic processing
  • FIG. 9 is a plot showing bed expansion ratio and pressure drop for “soft” agglomerates with and without magnetic excitation
  • FIG. 10 is a plot showing bed expansion ratio and pressure drop for “hard” agglomerates with and without magnetic excitation
  • FIG. 11 is a plot showing bed expansion ratio and pressure drop for conventional fluidization of“hard” agglomerates before and after magnetic processing;
  • FIG. 12 is a table showing minimum fluidization velocities for “soft” agglomerates, “hard” agglomerates, and an 80/20 mixture of hard/soft agglomerates;
  • FIGS. 13 ( a ) and 13 ( b ) are plots of particle size distribution for “soft” agglomerates with and without magnetic field application;
  • FIGS. 14 ( a ) and 14 ( b ) are plots showing bed expansion and collapse for a soft agglomerate system with magnetic excitation according to an exemplary embodiment of the present disclosure
  • FIG. 15 is a table showing minimum fluidization velocities and bed expansion ratios for “soft” agglomerates with different mass ratios of magnets to nanoparticles;
  • FIG. 16 is a table showing minimum fluidization velocities and bed expansion ratios for “soft” agglomerates with different intensities of magnetic field;
  • FIG. 17 is a table showing minimum fluidization velocities and bed expansion ratios for “soft” agglomerates with different frequencies
  • FIG. 18 provides a schematic diagram of an exemplary sound-assisted fluidization system according to the present disclosure.
  • FIGS. 19 ( a ) and 19 ( b ) provides images of bed behavior of SiO 2 nanoparticle agglomerates with and without sound excitation, respectively;
  • FIG. 20 provides a plot of bed expansion relative to superficial air velocity, with and without sound excitation, according to an exemplary embodiment of the present disclosure
  • FIG. 21 provides a plot of pressure drop relative to superficial air velocity, with and without sound excitation, according to an exemplary embodiment of the present disclosure
  • FIG. 22 provides images of fluidization behavior at different sound frequencies (300, 400, 500, 600 and 1000 Hz) according to an exemplary embodiment of the present disclosure
  • FIG. 23 provides a plot of dimensional bed height relative to sound frequency according to an exemplary embodiment of the present disclosure
  • FIG. 24 provides a plot of dimensional bed height relative to sound pressure level (dB) at two sound frequencies (100 and 400 Hz) according to an exemplary embodiment of the present disclosure
  • FIGS. 25 ( a ) and 25 ( b ) provide schematic diagrams of an exemplary rotating fluidized bed system according to the present disclosure
  • FIG. 26 provides a plot of bed pressure drop relative to air velocity for four (4) exemplary rotation speeds (indicated in terms of equivalent gravity force, in G) according to an exemplary embodiment of the present disclosure
  • FIG. 27 provides a plot of bed height relative to air velocity for four (4) exemplary rotation speeds according to an exemplary embodiment of the present disclosure
  • FIG. 28 provides a plot of pressure drop relative to air velocity for four (4) exemplary rotation speeds according to an exemplary embodiment of the present disclosure
  • FIG. 29 provides a further plot of bed height relative to air velocity for four (4) exemplary rotation speeds according to an exemplary embodiment of the present disclosure
  • FIG. 30 provides a further plot of pressure drop relative to air velocity for four (4) exemplary rotation speeds according to an exemplary embodiment of the present disclosure
  • FIG. 31 provides an additional plot of bed height relative to air velocity for four (4) exemplary rotation speeds according to an exemplary embodiment of the present disclosure
  • FIG. 32 provides a plot of fluidization velocity relative to centrifugal force for three exemplary powder systems according to the present disclosure
  • FIG. 33 provides nanoparticle properties for a series of powders in tabular form
  • FIG. 34 provides fluidization characteristics of APF nanoparticles in tabular form
  • FIG. 35 provides fluidization characteristics of ABF nanoparticles in tabular form
  • FIG. 36 is an exemplary graphical representation of pressure drop and bed expansion data as a function of velocity in accordance with an illustrative aspect of the present disclosure
  • FIGS. 37 ( a ) and 37 ( b ) are exemplary photographs showing a fluidization bed with and without vibration, respectively, in accordance with an illustrative aspect of the present disclosure
  • FIG. 38 provides a series of exemplary photographs showing a progression of mixing during aerated vibrofluidization in accordance with an illustrative aspect of the present disclosure.
  • FIG. 39 provides a series of exemplary photographs showing a progression of mixing during magnetically assisted nanofluidization in accordance with an illustrative aspect of the present disclosure.
  • homogeneous fluidization of nanoparticles is advantageously achieved by coupling aeration with vibration. Vibration (e.g., at frequencies in the range of 30 to 200 Hz, and vibrational acceleration in the range of 0 to 5 g) has been found to achieve smooth fluidization of nanoparticles.
  • Vibration e.g., at frequencies in the range of 30 to 200 Hz, and vibrational acceleration in the range of 0 to 5 g
  • the nanoparticle/nanoagglomerate particle size distribution is advantageously modified to and maintained in a distribution range that supports and maintains efficacious fluidization.
  • the minimum fluidization velocity (defined as the lowest gas velocity at which the pressure drop across the bed reaches a plateau) has been measured at approximately 0.3-0.4 cm/s, and been essentially independent of vibrational acceleration. Moreover, the bed expands almost immediately after the air is introduced, reaching bed expansions of three (3) times the initial bed height or higher. Hence, the bed appeared to exhibit a fluid-like behavior at velocities much lower than the minimum fluidization velocity. According to such exemplary embodiments, fluidization of nanoparticles is achieved due to the formation of stable, relatively large, and very porous agglomerates and bubbles/elutriation of particles were essentially non-existent.
  • Apparatus 1 essentially has a gas supply source 2 suitable for supplying a fluidizing gas, a vibration source 4 suitable for providing a mechanical force, and a magnetic source 6 suitable for providing a magnetic force.
  • Other features that may preferably be associated with the apparatus 1 include a gas inlet 8 , a gauge 10 for measuring gas flow, a distributor 12 , fluidization bed chamber 14 , a vent 16 and/or an accelerometer 18 .
  • apparatus 1 is well suited for aerated vibrofluidization.
  • the fluidization bed chamber 14 may have a tube portion 15 of glass or any other suitable material, including, for example, metal, plastic, or ceramic.
  • the tube portion 15 has an inner diameter that may preferably range from at least about one (1) centimeter to several meters.
  • electrostatic charge can be decreased, for example, via a DC-nozzle such as provided by Tantec, Inc.
  • a DC-nozzle can achieve static-neutralization by ionizing the air flowing through the fluidization bed chamber 14 by taking a voltage and transforming it into a high voltage.
  • the fluidization bed chamber 14 may be mounted on top of the vibration source 4 .
  • acceleration may be measured by the accelerometer 18 (e.g., a piezoelectric accelerometer).
  • fluidizing gases include air, nitrogen, helium, oxygen, argon and/or other gases suitable for fluidized bed chamber reaction.
  • the flow rate of the fluidizing gas may be measured with the gauge 10 , such as, for example, by a rotameter or alternatively, any other suitable flow measuring device.
  • a typical flow rate may fall anywhere in the range of about a fraction of a centimeter/second to several centimeters/second.
  • the fluidization bed chamber 14 having a cylindrical bed of about 3 inches is used with 12 nm silica particles (Aerosil® R972 silica)
  • a velocity of 1 cm/sec. may preferably be employed to achieve vigorous fluidization with high bed expansion.
  • vibrational parameters e.g., frequency, amplitude, and vibrational acceleration
  • inverter for example
  • suitable values for frequency might preferably range from about 20 to about 500 Hz
  • suitable values for amplitude preferably range from about 0.001 to about 13.81 mm
  • suitable values for acceleration may preferably be as high as about 20 g's.
  • pressure drop may easily be measured by a manometer or a pressure transducer, for example, and recorded either manually or electronically via a computer.
  • Operating efficacy may be monitored and/or observed, as desired, by photographing the apparatus 1 with a suitable camera, e.g., a digital camera to capture the behavior of fluidization, such as smooth or bubbling.
  • a fluidized bed consisting of a glass tube with an inner diameter of 6.25 cm and height of 35 cm was employed.
  • the fluidized bed was equipped with a series of ports for sampling and pressure measurements.
  • the distributor consisted of a porous sintered metal material.
  • the bed was mounted on top of a Ling Dynamic System vibrator, which can produce AC vertical sinusoidal waves with accelerations up to 5.5 g (where g is the acceleration due to gravity) measured by a piezoelectric accelerometer.
  • the frequency (f) of vibration could be varied from 30 to 200 Hz.
  • the powder used was Aerosil® R974 (Degussa) hydrophobic silica having a primary particle size, particle density, bulk density, and external surface area of 12 nm, 2200 kg/m 3 , 30 kg/m 3 , and 200 m 2 /g, respectively. These silica nanoparticles were at the extreme end of Geldart's group C powder classification. Humidity is an important issue when dealing with powders (especially hydrophilic powders) because of liquid bridges and electrostatic effects. However, in the experiments described herein, hydrophobic silica was employed such that humidity did not play as large a role, and bone dry compressed air was used as the fluidizing gas. The airflow rate was measured by a rotameter.
  • the vibration was turned on. Flow rate, pressure drop, vibrational acceleration, frequency and bed height measurements, as well as visual observation of the fluidization behavior for each experiment, were all recorded.
  • the pressure drop was measured by a pressure transducer and recorded on a computer. Photos were taken with a digital camera.
  • the dense layer simply contained the hard agglomerates, which were present in the as-received nanoparticles; such hard agglomerates could have formed during handling and storage. Under vibration, these large agglomerates would sink to the bottom of the bed since the vibration energy was not sufficient to break them up and the airflow was not large enough to fluidize them. In order to avoid a large agglomerate size distribution, only the top portion of the bed (smooth layer) was used in all of our experiments described below.
  • a Beckman Coulter counter (dry module) was used to determine the agglomerate size distribution of the as-received silica powder.
  • Representative Coulter counter results for pre-experiment powder indicated a mean agglomerate size of about 30-40 ⁇ m. This is highly suspect since large agglomerates of size on the order of millimeters (perhaps formed during storage) could be observed visually.
  • These contradictory results suggest that the agglomerates are in general so fragile that any measurement method involving direct contact with the sample is not effective and reliable. It is believed that the agglomerates were broken up during the course of Coulter counter size distribution measurements, leading to agglomerate sizes of about 30-40 ⁇ m.
  • agglomerate samples were aspirated out of the bed at different heights of the expanded fluidized bed and examined under SEM.
  • the agglomerate sizes averaged approximately 30 ⁇ m.
  • the agglomerates appeared very porous and fragile, and might have broken during their removal from the bed and/or during sample preparation for the SEM.
  • the agglomerate size estimated from pressure drop and bed height data in fluidization experiments was considerably larger ( ⁇ 160 ⁇ m). Given the fragile nature of the agglomerates, it is reasonable to expect that an equilibrium between agglomerate breakage and agglomerate formation is reached during the process of fluidization. Therefore, the true agglomerate size can only be found from measuring the agglomerates dynamically as fluidization is occurring.
  • the use of a high-speed digital camera with an extremely short exposure time and a laser beam may be effective to estimate the dynamic agglomerate size in situ.
  • FIG. 3 shows a comparison between the settling of a fully expanded bed after (a) aeration was left on and vibration was turned off, and (b) both aeration and vibration were turned off. Without both vibration and aeration, the bed collapsed to its initial height within two (2) minutes. Based on these experimental observations, it appears that once the interparticle forces are disrupted, it takes a finite time to return to the original undisturbed conditions.
  • FIG. 4 ( a ) shows bed expansion rate at different ⁇ at a constant frequency of 50 Hz and constant superficial air velocity of 0.28 cm/s.
  • the steady state bed expansion increased with increasing ⁇ , but appeared to become independent of ⁇ at sufficiently large values of ⁇ .
  • FIG. 4 ( b ) illustrates that the steady state bed expansion, at a constant superficial air velocity of 0.28 cm/s, depended on the frequency of vibration, even when ⁇ was maintained constant; however, no systematic trend was manifest. It was found that at higher values of ⁇ , the effect of vibration frequency on the steady state bed expansion decreased. It is clear from FIGS. 4 ( a ) and 4 ( b ) that at least two dimensionless groups involving A and ⁇ would be needed to capture the effect of vibration on fluidization behavior.
  • FIG. 5 shows a typical set of results obtained in a vibrated fluidized bed of silica nanopowder, where both the pressure drop across the bed and the bed expansion at increasing gas velocities are presented.
  • the pressure drop has been scaled with the actual measured weight of the bed per unit cross sectional area of the bed, while the bed height has been scaled with the height of the settled bed. It is clear from FIG. 5 that the pressure drop increased initially with gas velocity and then leveled off at high gas velocities. In the plateau region, the scaled pressure drop is very close to the expected value of unity.
  • a lower measured pressure drop than the weight of the bed could be due either to a loss of powder sticking to the wall, powder elutriation, or possibly to some non-uniformities in the gas flow due to the relatively porous distributor that was used in the experiments.
  • wall friction Liezos et al., 2002
  • cohesion between the bed of particles with a layer of particles adhering tightly to the distributor would result in a higher measured pressure drop than the weight of the bed.
  • Our studies have revealed only a weak effect of vibrational parameters on the constant (plateau) pressure drop obtained at high gas velocities. Thus, there is no clear consensus on the effect of vibration on pressure drop across the bed.
  • FIG. 5 also shows that bed expansion behavior in an exemplary system according to the present disclosure was different than that observed with Geldart group A particles where bed expansion begins only after the minimum fluidization velocity is exceeded.
  • a vibrofluidized bed with ⁇ >1
  • gas flow rate was increased, the bed continued to expand and this was accompanied by a systematic increase in the gas phase pressure drop.
  • the bed expansion continued into the constant pressure drop regime.
  • the overall bed expansion could be in excess of five times the original height, and even at such dramatic bed expansion levels the quality of fluidization appeared to be smooth.
  • the Reynolds number is less than 1.
  • a number of studies (Mawatari et al., 2002; Noda et al., 1998; Tasirin et al., 2001; Erdesz et al., 1986) have found that, as the vibration intensity, ⁇ , is increased, the minimum fluidization velocity is decreased.
  • minimum fluidization velocity refers to the lowest gas velocity for which the pressure drop across the bed becomes constant.
  • frequency and other vibrational parameters had only a small effect on the minimum fluidization velocity, and this effect became unobservable as ⁇ was increased.
  • the minimum fluidization velocity (based on the definition above) was determined to be around 0.3-0.4 cm/s (see FIG. 5 ). However, it is noted that the bed exhibited fluid-like properties as soon as it started to expand at velocities as low as 0.1 cm/s. Such a minimum fluidization velocity cannot be obtained empirically based on the primary particle size, which demonstrates unequivocally that the disclosed system is only fluidizing agglomerates.
  • voidage is defined as the fraction of the total bed volume occupied by the fluid. Using 0.03 g/cm 3 and 2.2 g/cm 3 for the bulk density of a settled bed and primary nanoparticles density, respectively, it is possible to calculate that ⁇ ⁇ 0.9864. Thus, the bed of nanoparticles is already highly fluffy even before fluidization. As the bed expands, ⁇ increases to above 0.99. The agglomerate themselves were very porous.
  • nanosized silica could be easily and smoothly fluidized in the form of stable, very porous agglomerates with negligible elutriation with the aid of vibration and aeration. Since the bed remained fluidized for a considerable amount of time with only air flow after vibration was turned off, vibration appeared to be necessary only initially to disrupt interparticle network and establish a desired particle size distribution, after which aeration was sufficient to sustain the bed in a fluidized and expanded state for an extended period of time, i.e., a dynamic equilibrium was established.
  • the mixing studies described above show that the application of vibrofluidization of nanoparticles to mix different nanoparticles together to form nanocomposites also yields promising and advantageous results.
  • the apparatus 1 may be well suited for aerated-magnetically assisted fluidization.
  • the apparatus 1 may preferably be substantially similar to that previously identified and/or described.
  • the vibration source 4 may preferably be either replaced by or supplemented with the magnetic source 6 preferably having one or more magnetic elements or particles, such as, for example, barium-ferrite polyurethane coated magnets. Other magnetic particles may also be used whose sizes range from about 0.5 to about 5.0 mm.
  • the magnetic source 6 also preferably has one or more magnetic field generators preferably surrounding a base portion 17 of the fluidization bed chamber 14 .
  • the energy dissipated from the collisions and/or spins of the magnetic particles due to interaction with a magnetic field induced by the magnetic field generators may be utilized to facilitate effective fluidization of nanoparticles. Further, utilizing different loads of the magnetic particles may be an effective way to affect the energy inputted into the fluidization bed chamber 14 . That is, the more magnetic particles used, the greater the energy provided.
  • the magnetic field may also be varied in order to change the energy input.
  • the magnetic field may, in one aspect of the invention, be induced via a copper coil, for example, to induce an oscillating magnetic field strength of approximately 40 mT.
  • the magnetic particles may also be comprised of magnetic powder embedded in a polymeric matrix, such as barium ferrite embedded in sulfur cured nitrile rubber such as ground pieces of PLASTIFORMTM Bonded Magnets, available from Arnold Engineering Co., Norfolk, Nebr.
  • the size of the magnetic particles may vary from about ten times to about thousand times the size of the powder material to be fluidized.
  • the appropriate size of the magnetic particles may depend on and/or be based on the type of application, the density of the powder material, and/or the cohesive strength of the powder material.
  • the appropriate size of the magnetic particles may be readily determined by one skilled in the pertinent art.
  • the shape of the magnetic particles may also vary, and may be spherical, elongated, irregular or other suitable shape.
  • the quantity of the magnetic particles required may be dependent on the quantity of the powder material to be moved, the bulk density of the particular powder material, the cohesiveness of the particular powder material, and/or environmental factors such as moisture, temperature, or time of consolidation. Preferably, only that quantity of magnetic particles needed to cause the powder material near the container outlet zone to move and/or flow may be used.
  • the weight of the magnetic particles should be approximately equal to the weight of the powder material near the outlet zone, for example, if a conical bottomed hopper is used, the weight of the magnetic particles should be approximately equal to the weight of the powder material in the lower half of the conical section.
  • the amount or weight of magnetic material may be less or more depending upon the nature of application.
  • the magnetic field generator(s) may preferably be supplied with power by means of oscillators, oscillator/amplifier combinations, solid-state pulsating devices and/or motor generators.
  • a magnetic field may preferably be generated by means of a solenoid coil, an air core or laminated metal cores, and/or stator devices or the like.
  • the magnetic field generator(s) may have one or more AC motor stators, i.e., motors preferably with armatures removed, which may be powered by an alternating current supply through variable output transformers.
  • metal strips may be placed outside the magnetic field generator(s) to preferably confine the magnetic field to a specific volume of space.
  • the magnetic field preferably oscillates either by changing the value in a sinusoidal fashion but keeping the direction the same, or by changing the direction of the field itself, so that the field rotates.
  • the oscillating magnetic field can be caused, for example, by using multiphase stators to create a rotating magnetic field, as disclosed in U.S. Pat. No. 3,848,363 to Loveness, or by using a single phase magnetic field generator with an AC power supply at a specified frequency to create a bipolar oscillating magnetic field.
  • a rotating field is preferred because the magnetic particles do not have a possibility of not being moved due to having an alignment with the direction of the field as in a bipolar field.
  • a useful magnetic field is preferably one with an intensity sufficient to cause desirable motion and excitation of the magnetic particles, but not large enough to demagnetize the magnetic character of magnetic particles that are moved by the oscillating magnetic fields.
  • the magnetic field intensity may range between about 1 oersted and about 3000 oersteds, preferably between about 200 and about 2500 oersteds.
  • the frequency of oscillations in the oscillating magnetic field affects the movement and subsequently the number of collisions that take place between a magnetic element preferably moved in the magnetic field and the surrounding powder material/particles preferably caused to move and/or to be fluidized. If the oscillating frequency is too low, the magnetic particles may move too slowly and may not have sufficient motion to cause the other powder material to flow. If the oscillating frequency is too high, the magnetic particles may not be able to spin in the fast changing field due to their inertia.
  • the frequency may be from about 5 hertz to about 100,000 hertz, preferably from about 50 hertz to about 1000 hertz, and even more conveniently at the hertz which is commonly used in AC power supplies (i.e., 50 hertz, 60 hertz, and/or 400 hertz).
  • the bed chamber 14 may of any suitable shape or configuration (e.g., tubular (3D) or rectangular (2D)) and may preferably be placed vertically in operative association with the equipment (i.e., the vibration source 4 and/or the magnetic source 6 ).
  • the distributor 12 may be made of several materials and take a variety of different forms.
  • the distributor 12 may be a sintered metal disk, a ceramic porous plate, or simple wire meshes or clothes, all with apertures preferably small enough (usually less than about 40 microns) to distribute the fluidizing medium as evenly as possible.
  • the top of the bed chamber 14 may be sealed with a cap and hose or tube, for example, leading to the vent 16 in case of any powder elutriation, which may occur at relatively high velocities.
  • the vibration and/or magnetic field may be set at the desired settings (e.g., acceleration, frequency, etc.).
  • an air flow may be slowly turned on.
  • One may verify effective fluidization using bed chamber expansion and pressure differentials.
  • the pressure drop may also be a good indicator when it equals the weight of the bed chamber per unit area.
  • Pressure taps may be drilled into the bed chamber at various desired heights thereof so that pressure drops across different places of the bed chamber may be obtained or quantified.
  • the measured pressure drop includes the distributor 12
  • the pressure difference of the distributor 12 must be subtracted from the total pressure drop recorded to obtain the drop across the powder bed. If a dense layer forms at the bottom of the bed chamber 14 near the distributor 12 , the top portion of the powder bed may be elutriated or physically taken out with an aspirator, for example, for later use in other applications (e.g., experiments without another dense layer forming).
  • samples may be taken for testing and analysis with SEM, EDX, TEM, EELS, etc. Average size, an overall mapping of the composition, and/or the degree of mixing may be obtained using such techniques. It is noted that if the powder material used is energetic, different and appropriate means of analysis may be used and extra caution should be taken when using energetic materials for fluidization. For example, an electrostatic charge may be significantly decreased using a DC nozzle that can ionize the fluidizing medium (e.g., air). Nonetheless, energetic samples such as, for example, nano-aluminum and nano-sized molybdenum oxide (MIC) may also be fluidized and well mixed in accordance with one or more aspects of the present invention.
  • MIC nano-aluminum and nano-sized molybdenum oxide
  • This system is applicable at temperatures that range from about ⁇ 100 degree C. to about 2000 degree C. and pressures that range from about 0.2 bars to about 2000 bars.
  • the temperature and/or pressure may be limited mainly by the particular material being fluidized and/or the materials used in constructing the apparatus 1 .
  • ambient temperatures and/or pressures e.g., room temperature and/or atmospheric pressure
  • Humidity should preferably be regulated so that moisture may be kept to a minimum. The presence of moisture may affect agglomeration of the powder material, although some humidity may be helpful to minimize electrostatic charges.
  • the powder material may preferably be collected in a clean container.
  • the magnetic particles used according to the present disclosure are permanent magnets, which furiously spin and create intense shear and agitations under an oscillating magnetic field.
  • the experimental system utilized herein consisted of a fluidized bed of nanoparticle agglomerates, an oscillating electromagnetic field and a visualization apparatus.
  • the fluidized bed was a vertical transparent column with a distributor at the bottom.
  • the column was a section of acrylic pipe with an inner diameter of 57 mm and a height of 910 mm.
  • the distributor was a sintered metal plate of stainless steel with a thickness of 2 mm and pore size of 20 ⁇ m.
  • glass beads of diameter between 2.5 and 3.5 mm were charged into a chamber placed below the distributor and above the gas inlet to form a packed bed about 100 mm high.
  • An ultra-fine mesh filter was located at the gas outlet to filter out any elutriated nanoparticle agglomerates.
  • the fluidization behavior was visualized with the aid of a lighting device (Illumination Technologies, Model 150SX) and recorded by a digital camcorder (Sony, Digital 8).
  • the magnetic particles were barium ferrite (BaO-6Fez03) coated with polyurethane (supplied by Aveka, USA), about 1.0-3.0 mm in size. These were permanent magnetic particles, which were recharged by contacting them with a strong permanent magnet before each experiment and were then added to the bed of nanoparticles at a prescribed mass ratio.
  • the shafts of two 1/20 HP electric motors (Dayton 5M064B) were removed and the electromagnetic coils were placed opposite one another around the lower part of the vertical transparent column by mounting them on an acrylic plate which holds the distributor.
  • the coils were driven by an alternating current generated by a power supply and were capable of generating an oscillating magnetic field with an intensity up to 140 Gauss at the center of the coil.
  • the power supply Triathlon Precision AC Source
  • a strong cooling fan Comair Rotron TNE2A was used to prevent the coils from overheating.
  • Fumed SiO 2 nanoparticles (Degussa Aerosil@ R974) with a primary particle size of 12 nm and a bulk density of about 30 kg/m 3 were used in these experimental studies. Due to surface treatment by the manufacturer, the nanoparticles were hydrophobic. Before the experiments, the particles were sieved using a shaker (Octagon 2000) and a 35-mesh sieve opening (about 500 ⁇ m). The sieving process functioned as a “pre-treatment” step with respect to the nanoparticle feedstock and served to separate very large agglomerates, which may have been generated during packing, storage, and transportation.
  • the selection of a mesh opening of 500 ⁇ m was based on previous experimental findings that the typical size of fluidized nanoparticle agglomerates is between 100 to 400 ⁇ m.
  • the size range of the fluidized nanoparticle agglomerates was measured by analyzing digital images of the fluidized agglomerates with the help of a laser source (Laser Physics Reliant 1000m), a CCD camera (LaVision FlowMaster 3S), and an image processing system (Dual Xeon CPU).
  • the smaller nanoagglomerates that pass through the openings of the 500 ⁇ m sieve are designated as “soft” and the larger agglomerates, from about 500 ⁇ m to more than 10 mm are designated as “hard”.
  • These two different sized agglomerates and a “mixture” consisting of 80% soft agglomerates and 20% hard agglomerates by weight (80/20) were selected to conduct the fluidization experiments described herein.
  • the bed shows very different fluidization behavior.
  • the soft R974 agglomerates fluidize smoothly with large bed expansion (APF) at a low minimum fluidization velocity of 0.23 cm/s.
  • APF large bed expansion
  • a mixture consisting of 80% soft agglomerates and 20% hard agglomerates (80/20) also behaves as APF, but the minimum fluidization velocity is much higher (5.67 cm/s) than that of the soft agglomerates.
  • the hard R974 agglomerates do not fluidize at all, even at a gas velocity as high as 13.2 cm/s. At this high gas velocity, significant particle elutriation was observed, and the fluidization experiment had to be interrupted to avoid large losses of nanoparticles.
  • Typical fluidization behavior of the 80/20 mixture of SiO 2 nanoparticle agglomerates with and without the external oscillating magnetic excitation are shown in the photographic images of FIGS. 6 ( a ) and 6 ( b ), respectively.
  • the nanoparticle agglomerates are first lifted as a plug and then the plug disintegrates to form undesirable, stable channels through which the gas passes; the bed expands slightly with an uneven surface and the pressure drop is much less than the bed weight, indicating that the nanoagglomerate bed is not fluidized.
  • the magnetic particles are set in motion (translation and rotation) and the nanoparticle agglomerates are fragmented into smaller agglomerates because of collisions with the magnets, the vessel wall, and the distributor.
  • the particle size distribution of the nanoparticle agglomerates are brought into a desirable range, the channels disappear, and the bed begins to expand slowly and uniformly until it reaches its full expansion, of up to five (5) times the initial bed height.
  • the pressure drop reading is very close to the weight of the bed, indicating fluidization of the entire bed.
  • a homogenous fluidization state is established, as shown in FIG. 6 ( b ), and the surface is very smooth and even.
  • the powder was poured out and, from visual observation, most of the original large hard agglomerates are gone and the average agglomerate size appears very much smaller.
  • FIG. 7 The pressure drop normalized with the bed weight per unit area and the bed expansion ratio as a function of superficial gas velocity through the bed are shown in FIG. 7 (with and without magnetic excitation). As shown therein, solid lines reflect bed expansion ratios and dashed lines reflect pressure drops.
  • the magnetic field intensity was 140G at the center of the field, and the mass ratio of magnets to nanoparticles was 2:1 (with AC frequency of 60 Hz).
  • U mf1 represents the minimum fluidization velocity without magnetic excitation
  • U mf2 represents the minimum fluidization velocity with magnetic excitation. It is clear from FIG. 7 that the magnetic excitation causes the bed to expand almost immediately as the velocity is increased and the bed fluidizes at a velocity more than one order of magnitude lower than that without magnetic assistance.
  • FIG. 8 is a comparison of the fluidization characteristics of the 80/20 mixture, before and after magnetic processing. Solid lines represent bed expansion ratios and dashed lines represent pressure drops. The magnetic field intensity was 140 G at the center of the field and the mass ratio of magnets to nanoparticles was 2:1 (AC frequency of 60 Hz).
  • the fluidization behavior of exemplary soft agglomerates is shown in FIG. 9 .
  • Solid lines represent bed expansion ratios and dashed lines represent pressure drops.
  • the magnetic field intensity was 140 G at the center of the field and the mass ratio of magnets to nanoparticles was 2:1 (AC frequency of 60 Hz).
  • U mf1 represents the minimum fluidization velocity without magnetic excitation
  • U mf2 represents the minimum fluidization velocity with magnetic excitation.
  • the much smaller agglomerates fluidize well with and without magnetic excitation.
  • the minimum fluidization velocities appear to be quite close to each other, but at higher gas velocities (above minimum fluidization velocity), the bed expansion with magnetic assistance is higher than that without magnetic assistance.
  • the ratio of the measured pressure drop to the weight of the bed per unit area is below unity for magnetic assisted fluidization. This may mean that some of the nanoagglomerates are not participating in the fluidization and may be sticking to the magnets.
  • FIG. 10 shows the typical fluidization behavior (pressure drop and bed expansion) of hard SiO 2 nanoparticle agglomerates (R974) with and without magnetic excitation. Solid lines represent bed expansion ratios and dashed lines represent pressure drops.
  • the magnetic field intensity was 140 G at the center of the field and the mass ratio of magnets to nanoparticles was 2:1 (AC frequency of 60 Hz).
  • U mf1 represents the minimum fluidization velocity without magnetic excitation
  • U mf2 represents the minimum fluidization velocity with magnetic excitation.
  • the size of the hard agglomerates was in a wide range, from 0.5 mm to about 10 mm. Without the magnetic excitation, even at superficial gas velocity as high as 13.2 cm/s, the hard agglomerates could not be fully fluidized.
  • the large agglomerates become smaller and smaller due to fragmentation (disruption of interparticle forces) caused by collisions with the magnetic particles, and these smaller agglomerates participate in the circulation of the bed.
  • the nanoparticle size distribution reaches a desired range and assumes a dynamic equilibrium. From that point, even at the relatively low gas velocity of 0.94 cm/s, all of the large agglomerates disappear, and the bed expands slowly and uniformly until it reaches full expansion, while the pressure drop reading is very close to the weight of the bed, indicating that the entire bed is fluidized.
  • FIG. 11 is a comparison of the fluidization characteristics between the powder before and after undergoing a magnetic assisted fluidization (fragmentation) process according to the present disclosure. Solid lines represent bed expansion ratios and dashed lines represent pressure drops.
  • the magnetic field intensity was 140 G at the center of the field and the mass ratio of magnets to nanoparticles was 2:1 (AC frequency of 60 Hz).
  • U mf1 represents the minimum fluidization velocity before magnetic fragmentation processing
  • U mf2 represents the minimum fluidization velocity after magnetic fragmentation processing.
  • a very large reduction in the minimum fluidization velocity (U mf ) from greater than 13.2 cm/s to 2.29 cm/s indicates that the average agglomerates size has been significantly reduced through the magnetic fragmentation processing.
  • the U mf for the hard agglomerates after magnetic processing is 2.29 cm/s, which is larger than the U mf of 1.25 cm/s for the 80/20 mixture, and also much larger than the U mf of 0.23 cm/s for the soft agglomerates.
  • the soft agglomerates represent a good choice to conduct the comparison experiments.
  • the mechanism of fluidization with the assistance of an oscillating magnetic field is two-fold: (1) fragmentation of large agglomerates into smaller ones, and (2) transferring kinetic energy generated by the oscillating magnetic excitation to the nanoparticle agglomerates due to collisions to disrupt the large interparticle forces between them.
  • the table of FIG. 12 presents a summary of the minimum fluidization velocities for the soft, hard and 80/20 agglomerate mixture.
  • magnetic excitation has little effect, but it produces a definite improvement in fluidization behavior for the 80/20 mixture.
  • Even for the hard agglomerates magnetic excitation changes the fluidization characteristics significantly, from no fluidization to smooth, bubble-less, agglomerate particulate fluidization (APF) with very large bed expansion up to five (5) times the initial bed height.
  • APF agglomerate particulate fluidization
  • the minimum fluidization velocity is also significantly reduced from higher than 13.2 cm/s to 0.38 cm/s. Without magnetic excitation, at a gas velocity of 13.2 cm/s or higher, extremely strong elutriation could be observed, while with magnetic excitation, at the low gas velocity of 0.38 cm/s, elutriation was negligible.
  • the substantial reduction in the minimum fluidization velocity resulting in smooth and bubble-less fluidization with little elutriation offers significant benefits for industrial applications where good mixing and high rates of heat and mass transfer with little gas by-passing are required.
  • FIGS. 13 ( a ) and 13 ( b ) demonstrate that the mean agglomerate size of the decreases by roughly 100 ⁇ m during magnetic processing (from mean measurement of 315 ⁇ m to mean measurement of 196 ⁇ m).
  • the agglomerate size distribution is advantageously shifted downwards through magnetic processing according to the present disclosure, establishing a dynamic equilibrium that facilitates effective bed fluidization.
  • FIG. 13 ( a ) reflects the particle size distribution for a “soft” agglomerate system without magnetic field application (i.e., control) and
  • FIG. 13 ( b ) reflects particle size distribution with magnetic field application (140 G, 60 Hz, mass ratio of magnets to nanoparticles of 2:1).
  • the data reflected in FIGS. 13 ( a ) and 13 ( b ) was generated through in situ optical measurements on the fluidized bed surface.
  • the table of FIG. 16 presents the values of U mf and bed expansion ratio at a fixed superficial gas velocity for three different magnetic field intensities when fluidizing soft nanoagglomerates, keeping the ratio of magnets to nanoparticles at 2:1.
  • the center point of the column around which the 2 coils are placed was selected as the reference point for measuring the intensity of the magnetic field and it was observed that, when using a magnetic field intensity of less than 80 G, the bed could not be fluidized.
  • three (3) different intensities 100, 120, and 140 G
  • the minimum fluidization velocity is a strong function of the magnetic field intensity and U mf and decreases rapidly as the intensity of the magnetic field increases, indicating better fluidization.
  • the values of the bed expansion are quite close to one another, but they are nonetheless consistent with the trend that the bed will expand more in a stronger magnetic field.
  • the table of FIG. 17 presents the values of U mf and bed expansion ratio at a fixed superficial gas velocity for three (3) different frequencies of AC power, keeping the mass ratio of magnets to nanoparticles at 2:1 and the magnetic field intensity at 120 G at the center of the field.
  • the table shows that the frequency of the magnetic field can significantly affect the minimum fluidization velocity.
  • the beds show similar fluidization behavior, and can be fluidized easily at a U mf of 0.65 cm/s and 0.51 cm/s, respectively.
  • U mf is as high as 2.64 cm/s
  • the bed expansion is much smaller than at the lower frequencies.
  • the bed could not be fluidized at all.
  • silica nanoparticle agglomerates can be easily and smoothly fluidized with the assistance of magnetic particles in an oscillating magnetic field. Due to a significant reduction in the minimum fluidization velocity with magnetic assistance, both elutriation of nanoparticle agglomerates and gas bypass in the form of bubbles is greatly reduced. With magnetic excitation, hard (larger than 500 ⁇ m) agglomerates change their fluidization pattern from no fluidization to agglomerate particulate fluidization (APF) with large bed expansion. The minimum fluidization velocity of an 80% soft (smaller than 500 ⁇ m) and 20% hard agglomerate (80/20) mixture can also be significantly reduced.
  • APF agglomerate particulate fluidization
  • Magnetic-assisted nanoparticles fluidization is easier to achieve and yields more uniform fluidization, and such approach can be used for “as-received powders”, i.e., straight out of the bag, without any pre-processing, and hence is very useful for practical applications.
  • the introduction of the magnetic energy according to the present disclosure significantly alters agglomerate size, reducing it to achieve a desired size distribution, and allowing for advantageous fluidization performance results.
  • the fluidization of nanoparticles and/or nanoagglomerates in accordance with one or more aspects of the present invention may have a great impact on the processing and manufacturing of nanostructured products. It is known that mechanical, electronic, catalytic, optical, and/or other properties of a material are significantly enhanced when made of nanoparticle components. For example, copper preferably composed of nanocrystalline copper may be 5 times harder than copper that is composed of micron-sized copper particles. Further, the mixing of nanosized aluminum and molybdenum oxide to produce MIC, an energetic material that may have a variety of important military applications. It has been ascertained that good mixing of the two components on the nanoscale, as provided by the present invention, is essential for obtaining a viable, highly energetic product.
  • the apparatus of the present invention may be provided with a spray nozzle preferably located above the bed surface.
  • the spray nozzle is preferably suitable to spray the surface, where the particles are continuously circulating throughout the bed.
  • the spray nozzle may preferably be sized to deliver an appropriate amount of material for a desired amount of coating. Due to the loose structure of the agglomerates, individual coating of primary particles may only be forthcoming.
  • a bed of nanoparticle agglomerates can be readily fluidized and the minimum fluidization velocity is significantly reduced.
  • an exemplary nanoparticle material namely hydrophobic fumed silica nanoparticles (Degussa Aerosil® R974 having a primary particle size of 12 ⁇ m) in the form of large 100 to 400 ⁇ m agglomerates
  • the minimum fluidization velocity was decreased from 0.14 cm/s in the absence of sound excitation to 0.054 cm/s with the assistance of sound wave excitation.
  • channeling or slugging of the bed quickly disappeared and the bed expanded uniformly.
  • sound waves are advantageously employed for fluidization purposes, either alone or in combination with other external energy sources, to provide excitation to nanoparticles that is relatively inexpensive, affects the entire particle bed, and does not require any physical contact between the sound generator and the nanoparticles.
  • the advantageously disclosed sound-assisted fluidization of nanoparticle agglomerates and their fluidization characteristics are not only different from those observed using other fluidization methods for nanoparticle agglomerates, but are also different from sound-assisted fluidization of micron or sub-micron sized particles.
  • the effects of sound frequency and sound pressure level on the fluidization behavior such as the minimum fluidization velocity, bubbling regime, pressure drop across the bed, and bed expansion, are also disclosed herein.
  • FIG. 18 A schematic diagram of an exemplary sound-assisted fluidization system 100 is shown in FIG. 18 .
  • the exemplary system 100 includes a fluidized bed 102 containing nanoparticle agglomerates 104 , a sound excitation device 106 , and a visualization apparatus 108 .
  • the visualization apparatus 108 is provided for the sole purpose of monitoring the activities and/or behavior of the nanoparticles within fluidized bed 102 , and is not required for implementations wherein such monitoring is not necessary or desirable.
  • the exemplary fluidized bed 102 is a vertical transparent column with a distributor 110 at the bottom.
  • the column is fabricated from a section of acrylic pipe with an inner diameter of 57 mm and a height of 910 mm.
  • the exemplary distributor 110 is a sintered metal plate of stainless steel with a thickness of 2 mm and pore size of 20 ⁇ m.
  • Ultra-fine mesh filters 112 are located at the gas outlet to filter out any elutriated nanoparticle agglomerates.
  • the disclosed sound excitation device 106 includes a 63 mm loudspeaker 114 that is powered by a sound amplifier 116 that communicates with a signal generator 118 .
  • the loudspeaker 114 is installed on the top of fluidized bed 102 .
  • a precision sound pressure level meter (not pictured) may be used to measure the sound pressure level.
  • sound excitation system 106 is capable of generating a sound wave in fluidized bed 102 with a sound pressure level up to 125 dB and the sound frequency from signal generator 118 is typically adjustable, e.g., within a range extending from 10 to 2 MHz.
  • the fluidization behavior of the nanoparticles is visualized with the aid of a lighting device (not pictured) and is recorded by a digital camcorder 120 .
  • the visual images may be advantageously analyzed directly by a computer 122 .
  • synthetic silicon dioxide nanoparticles (Degussa, R974) with a primary particle diameter of 12 nm and a primary density of 2560 kg/m 3 were employed.
  • the disclosed sound-assisted fluidization system is not limited to use with silicon dioxide nanoparticles, however, but may be employed with a variety of nanoparticle materials finding application in a variety of commercial fields.
  • the nanoparticles were sieved using a shaker (Octagon 2000) and a sieve of Mesh No. 35 (mesh opening, about 500 ⁇ m). The sieving process served to remove very large agglomerates which may have been generated during packing, storage, and transportation.
  • the selection of a mesh opening of 500 ⁇ m reflects the fact that the typical size of fluidized nanoparticle agglomerates is between 100 to 400 ⁇ m (although the present disclosure is not limited to such particle size distributions).
  • the bulk density of the sieved nanoparticle agglomerates was 33.8 kg/m 3 .
  • the silicon dioxide nanoparticles are hydrophobic.
  • pure nitrogen from a compressed N 2 tank 122 was used as the fluidizing gas.
  • the gas flow rate was measured and adjusted by a calibrated rotameter 124 .
  • an inclined tube monometer 126 With the aid of an inclined tube monometer 126 , the pressure drop across the bed was measured. By measuring the pressure in the manner schematically depicted in FIG. 18 , the pressure drop across distributor 110 was excluded.
  • FIGS. 19 ( a ) and 19 ( b ) Typical bed behavior of SiO 2 nanoparticle agglomerates with and without sound excitation are shown in FIGS. 19 ( a ) and 19 ( b ), respectively.
  • the nanoparticle agglomerates were first lifted in a slugging mode and then the bed disintegrated to form stable channels.
  • the bed only expands slightly with an uneven surface, as shown in FIG. 19 ( a ).
  • the instabilities in the bed collapse in a couple of seconds, the channels disappear, and the bed expands rapidly and uniformly until it reaches the full expansion.
  • a homogenous fluidization state is easily established, as shown in FIG. 19 ( b ).
  • Typical fluidization characteristics including the minimum fluidization velocities, bed expansions and bed pressure drops with and without sound excitation, are illustrated in FIGS. 20 and 21 , respectively.
  • An advantageous substantial reduction in the minimum fluidization velocity with the introduction of the disclosed sound energy is apparent.
  • the minimum fluidization velocity was reduced from 0.14 cm/s in the absence of sound energy to 0.054 cm/s with sound excitation.
  • the minimum fluidization velocity is defined as the gas superficial velocity beyond which the bed pressure drop is no longer dependent upon the gas velocity and becomes nearly constant.
  • FIG. 22 shows a series of representative snapshots of the fluidizing bed at different sound frequencies.
  • a fixed sound level output e.g., 125 dB in FIG. 22
  • the bed of nanoparticle agglomerates can only be fluidized in a relatively narrow band of low sound frequency from 20 to 1000 Hz.
  • bubbles appear in an even narrower range, 200-600 Hz, and as seen in FIG. 22 , both the occurrence of bubbling and bubble size are strongly dependent on the sound frequency.
  • the bed expansion is also strongly dependent on the sound frequency, as seen in FIG. 23 .
  • FIG. 24 The effect of sound pressure level on the bed expansion is shown in FIG. 24 . It is noted that below a critical value of sound pressure level (e.g., 112 dB at 1000 Hz and 105 dB at 400 Hz in FIG. 24 ), there is no fluidization. The critical sound pressure level appears to be a function of sound frequency. Within the range of the test conditions reflected in FIG. 24 , the bed expansion increases monotonically as the sound pressure level increases.
  • Bed expansion and overall fluidization performance are related, at least in part, to the balance between the sound-assisted agglomerate breakup and the sound-assisted agglomeration of the nanoparticles.
  • the introduction of sound energy reduces agglomerate size and, once a desired agglomerate size distribution, advantageous fluidization performance results.
  • the introduction of sound energy to a nanoparticle system contributes to a reduction in particle size distribution, thereby enhancing bed expansion and fluidization (e.g., up to frequencies of about 1000 Hz), as well as reductions in minimum fluidization velocities (e.g., R974 reduced from 0.2 cm/s to 0.05 cm/s; TiO 2 reduced from 5.17 cm/s to 2.29 cm/s).
  • bed expansion and fluidization e.g., up to frequencies of about 1000 Hz
  • reductions in minimum fluidization velocities e.g., R974 reduced from 0.2 cm/s to 0.05 cm/s; TiO 2 reduced from 5.17 cm/s to 2.29 cm/s.
  • fluidization behavior of nanoparticle systems is enhanced.
  • the enhanced fluidization behavior achieved through sound energy introduction supports or facilitates more uniform mixing, faster surface reaction and/or better surface coating.
  • nanoparticle agglomerates can be easily and smoothly fluidized with the assistance of sound energy at an appropriate sound pressure level and sound frequency. Since there is a significant reduction in the minimum fluidization velocity in the presence of sound, elutriation of nanoparticle agglomerates is much reduced.
  • the ability to fluidize the exemplary fumed silica nanoparticle agglomerates could only be achieved within a given range of sound frequency with a sound pressure level above a critical value. Bubbling fluidization occurs within an even smaller range of sound frequency.
  • a rotating fluidizing bed (RFB) system and associated method/process are provided for use in advantageously fluidizing nanoparticles/nanopowders/nanoagglomerates.
  • Use of the disclosed rotating fluidized bed system demonstrates a linear dependence between the minimum fluidization velocity and the centrifugal force delivered thereby.
  • the centrifugal force is generally dependent on such factors as the dimensions of the rotating system and the rotational speed thereof. For example, conditions may be selected whereby the rotating system generates various force levels, e.g., forces that are 10, 20, 30 and 40 times normal gravity force.
  • Rotating unit 200 includes a chamber 202 that encloses a cylindrical porous stainless steel sintered mesh 204 with an aperture size of 20 ⁇ m, 2 mm of thickness, 400 mm of diameter and 100 mm of depth.
  • Mesh 204 functions to distribute the gas that passes through the bed, i.e., as a gas distributor. This gas distributor turns along its axis of symmetry, moved by a motor 206 which is controlled by a speed variator.
  • Rotating unit 200 also includes a stationary cylindrical filter 208 of 100 ⁇ m mesh with 2 mm of thickness, 100 mm of diameter and 90 mm of depth; the function of stationary filter 208 is to retain elutriated fine powder.
  • the covers of chamber 202 and mesh/gas distributor 204 are typically fabricated of an appropriately rigid material, e.g., acrylic plastic. In an exemplary material, the covers are fabricated from a transparent or translucent material which allows the behavior of the bed inside the unit to be viewed.
  • Pressure taps 210 are placed between gas distributor 204 and the inner filter mesh 208 , as shown in FIGS. 25 ( a ) and 25 ( b ).
  • the pressure drop across the air distributor may be measured using a differential pressure transmitter.
  • the gas, e.g., air, delivered to the distributor may be measured by an area variable type flowmeter 212 . Since it is generally not possible to measure the bed pressure drop directly in a rotating fluidized bed, the pressure drop across the air distributor mesh 204 may be determined as a function of air velocity or flow rate before loading rotating unit 200 with powder. Then the bed pressure drop can be quantified by subtracting the pressure drop measured when the unit is loaded with powder, and when the unit is empty.
  • a digital camera may be associated with rotating unit 200 for use in recording the behavior of nanoparticle agglomerates during fluidization.
  • a laser light may be used to determine the expansion of the bed as well as the homogeneity of the bed's surface.
  • a vacuum system may be employed to remove exhaust from rotating unit 200 and the pressure transmitter may be advantageously connected to a computer system for processing of data received therefrom.
  • the powders were sieved using a shaker and a sieve of Mesh No. 60 (mesh opening about 250 ⁇ m). This sieving procedure was followed because it is believed that the large agglomerates break the homogeneity of the flow field and make the fluidization more difficult.
  • Fumed Silica Aerosil was employed having an approximate tapped density of 50 g/l.
  • the R974 material had an average particle size of 12 nm, while the R972 material had an average particle size of 16 nm. In both cases, 70 grams were used; the bulk density of these powders was approximately 30 g/l.
  • the tested titanium dioxide P25 material had an average particle size of 21 nm, a tapped density of 130 g/l, and a bulk density of about 90 g/l. A total of 250 grams were used in the experiments and the initial bed height was close to 0.02 m.
  • the experimental steps can be summarized as follows.
  • the unit was cleaned very carefully so as to ensure a uniform air field would be generated by the air distributor. All of the component parts of the rotating unit were assembled and all joints sealed in order to prevent leaks. The presence of leaks would undesirably distort collected pressure drop data.
  • the pressure drop across the air distributor was then measured. For this purpose, the unit was run empty, and the air flow and the rotating speed were changed successively in order to find the relationship between the distributor's pressure drop and the air flow.
  • test material was loaded into the unit and the rotating speed was set at the desired value in order to increase the centrifugal force.
  • the air flow was increased slowly and relevant data was recorded, i.e., air flow, pressure drop and bed height.
  • relevant data was recorded, i.e., air flow, pressure drop and bed height.
  • the rotating speed was increased to higher values and the same procedures were followed with respect to data collection.
  • FIG. 26 shows the measured air pressure drops at different values of air velocity and at different rotating speeds translated in “G”s (i.e., translated into gravity forces).
  • the pressure drop increases until the minimum fluidization velocity is reached, then a constant pressure drop is observed. It is noted that the pressure drop does not uniformly maintain a linear trend before reaching the minimum fluidization velocity (U mf ); it is believed that due to the centrifugal force imparted by the rotating unit, the powder was compacted and therefore the changing pressure is due to the irregularities of the bed before reaching the fluidized state.
  • FIG. 27 shows the relative bed height as a function of air velocity for the tested R974 material. It is noted that the compaction effect over the bed that is effected by the centrifugal field changes the bulk density of the powder. Bed pressure drop data related to the fluidization behavior of R972 material is shown in FIG. 28 .
  • FIG. 29 shows the relative bed height during fluidization of the R972 material. In the case of R972 material (as with the R974 material), there is a compaction effect over the powder as the centrifugal field increases. It is believed that the centrifugal force is transmitted to all particles in the bed by the particles that are in closer proximity to the air distributor.
  • FIG. 30 shows the fluidization behavior for titanium dioxide P 25 material.
  • the amount of titanium dioxide loaded into the unit for the experimental runs described herein was higher than the amount of fumed silica because the bulk density of the titanium dioxide is approximately three (3) times that of the silica; therefore, a larger pressure drop was expected due to the increase of the weight of the bed within the system.
  • bed height response for the titanium dioxide material and as shown in FIG. 31 , there is not a large bed expansion as was experienced with the R974 and R972 silica powder materials.
  • measurement of the increase in bed height was very difficult to achieve. This difficulty can be explained due to the higher density (bulk and particle) of the titanium dioxide powder. No significant elutriation was observed during the titanium dioxide experimental runs.
  • fluidization behavior in the rotating bed systems of the present disclosure differs based, at least in part, on the characteristics of the particles processed in such systems.
  • the bed expansion behavior can facilitate determination of the fully fluidized system state.
  • the TiO 2 P25 material the bed expansion was poor and unstable, thereby giving no useful insight with respect to the fluidization state of the system.
  • FIG. 32 shows the relationship between minimum fluidization velocity and centrifugal force for the three tested material systems.
  • the experimental pressure drop measurements can be affected by several problems during the experimental runs described herein, such as clogging of the distributor, leaks across the distributor assembly, inaccuracies in the readings of the flow rate, problems in the pressure reading system, etc.
  • these systematic errors generally exhibit a level of repeatability that can be determined and, therefore, actions can be taken to address the underlying problem(s).
  • Preliminary analysis shows that the theoretical predictions for the pressure drop in a rotating fluidized bed only consider the effect due to the centrifugal forces, and do not account for the effects of the relative magnitude between the radial and tangential velocities and the gradient of the tangential velocity in the radial direction.
  • Nanoparticles differ in this respect from micron and larger particles, because the radial air velocities for nanoparticles are much lower than those for the micron and larger sized particles.
  • Kao et al. Kao et al., On Partial Fluidization in Rotating Fluidized Beds, AIChE J. 33 (1987) 858]
  • Kao et al. On Partial Fluidization in Rotating Fluidized Beds, AIChE J. 33 (1987) 858
  • the effects of different types of nanoparticles on gas fluidization characteristics of nanoparticle agglomerates was determined. Taking advantage of the extremely high porosity of the bed, optical techniques were used to visualize the flow behavior, as well as to measure the sizes of the fluidized nanoparticle agglomerates at the bed surface. Upon fluidizing a series of different nanoparticle materials, two types of nanoparticle fluidization behavior were observed, namely agglomerate particulate fluidization (APF) and agglomerate bubbling fluidization (ABF).
  • APF agglomerate particulate fluidization
  • ABSF agglomerate bubbling fluidization
  • APF smooth fluidization without bubbles at minimum fluidization
  • ABF bubbles at minimum fluidization
  • APF agglomerates show very large bed expansions, up to five times the initial bed height as the superficial gas velocity is raised, and the Reynolds numbers for these nanoagglomerates at minimum fluidization are very low (0.05 to 0.35), which indicate that the agglomerates are in creeping flow.
  • ABF nanoagglomerates fluidize with large bubbles and show very little bed expansion as the superficial gas velocity is raised and the Reynolds numbers at minimum fluidization are close to or higher than 2.0, which indicate that hydrodynamic inertial effects cannot be neglected.
  • the porous nanoparticle agglomerates of the present disclosure behave differently than the classical solid particles used to obtain equation (1). Nonetheless, the values of the dimensionless groups (which are designated as “ ⁇ ”) were calculated for a series of tested nanoparticle materials. Unexpectedly and as shown in the Tables included as FIGS. 34 and 35 herein, the calculated results agree remarkably well with this criterion of formula (1).
  • the values of ⁇ are within the range of 0.008 ⁇ 1.55 (which is much less than 100)
  • the values of ⁇ are within the range of 398 ⁇ 1441 (which is much larger than 100).
  • the criteria set forth in formula (1) appear to be valid for nanoparticle agglomerates and therefore provide a valuable tool or methodology for determining whether a nanoparticle of interest will behave as APF or ABF.
  • a classification criterion based on the value of a combination of dimensionless groups to differentiate between particulate and bubbling fluidization for classical solid fluidized particles may be advantageously employed to predict whether nanoparticles will behave as APF or ABF. Indeed, utilization of this criterion may be superior to using the size and bulk density of the nanoparticles to predict their fluidization behavior.
  • nanopowders may be fluidized provided the nanoparticles are well-sieved so that large, hard agglomerates are removed. This advantageous result further enhances the flexibility and effectiveness of nanoparticle fluidization systems according to the present disclosure.
  • one or more of the energy modalities disclosed herein may be advantageously employed either alone or in combination.
  • the following energy source combinations may be employed to achieve advantageous fluidization of nanoparticles according to the present disclosure:
  • systems and methods/processes for fluidization of nanoparticles that exhibit numerous advantageous properties and results, including: less elutriation of powder, lower minimum fluidization velocities, in certain cases, higher air flow rate, higher powder load by unit area of distributor, reduction of the size of agglomerates due to the higher shear rate, improved mass-transfer and shorter processing time.
  • a fluidizing gas source e.g., combinations of at least two ancillary energy sources selected from among vibratory forces, magnetic forces, sound/acoustic forces, and rotational/centrifugal forces
  • the application of such external energy sources may be supplied at levels such that, in combination, the ancillary energy supplied to the fluidization system affects the desired nanoparticle fluidization results.
  • the disclosed systems and methods/processes may also be employed with a variety of fluidizing gases, e.g., air, N 2 , He, Ar, O 2 and/or combinations thereof.
  • the ability to supply multiple types and levels of energy provides significant control and flexibility to the fluidization of nanoparticle systems.
  • the advantageous fluidization systems and methods/processes disclosed herein may be used in processing a wide variety of nanoparticle materials for use in various applications, including applications that involve the manufacture of drugs, cosmetics, foods, plastics, catalysts, energetic and bio materials, high-strength or corrosion resistant materials, and in mechatronics and micro-electro-mechanical systems.
  • Effective dispersion of nanoparticles is achieved according to the present disclosure, thereby facilitating a host of nanoparticle-related processing regimens, e.g., mixing, transporting, surface property modifications (e.g., coating), and/or downstream processing to form nano-composites.
  • An apparatus as shown in FIG. 2 was used to fluidize nanopowders using any gas such as air or nitrogen and vibration.
  • FIG. 36 shows an exemplary plot of observed pressure drop and bed expansion vs. superficial air velocity.
  • the bed begins to expand and continues to expand both before and after the minimum fluidization velocity, defined as the velocity at which the pressure drop across the bed is equal to the weight of the bed divided by its cross sectional area.
  • the bed expanded to four times its initial height and appeared to be uniformly fluidized with negligible elutriation.
  • silica powders were fluidized.
  • FIGS. 37 ( a ) and 37 ( b ) illustratively show what may typically occur during a fluidization process. With air or vibration alone, nothing useful occurs to a conventional nanoparticle powder bed. When the two are coupled together, however, the nanoparticle size distribution is reduced/lowered and the powder bed expands with vigorous particle movement.
  • FIG. 38 shows the progression of mixing 12 nm silica with a small amount of the same nano-sized silica dyed with methylene blue.
  • the bed was operated at a constant air velocity of 0.45 cm/see with a vertical sinusoidal vibration of 4 g's at a frequency of 50 Hz.
  • a vertical sinusoidal vibration of 4 g's at a frequency of 50 Hz.
  • the silica was fluidized.
  • a coated nano-powder mixture of pigment and polymeric material may be fluidized for powder coating application.
  • Metallic objects to be coated may be heated to temperatures above the melting temperature of the polymer and dipped in the fluidized bed for an amount of time dependent upon the coating thickness desired. Very uniform, thin coatings may be achieved after processing.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • General Health & Medical Sciences (AREA)
  • Nanotechnology (AREA)
  • Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Toxicology (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
US10/900,868 2003-07-29 2004-07-27 System and method for nanoparticle and nanoagglomerate fluidization Abandoned US20060086834A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US10/900,868 US20060086834A1 (en) 2003-07-29 2004-07-27 System and method for nanoparticle and nanoagglomerate fluidization
US11/605,176 US7658340B2 (en) 2003-07-29 2006-11-28 System and method for nanoparticle and nanoagglomerate fluidization

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US49091203P 2003-07-29 2003-07-29
US56813104P 2004-05-04 2004-05-04
US10/900,868 US20060086834A1 (en) 2003-07-29 2004-07-27 System and method for nanoparticle and nanoagglomerate fluidization

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US11/605,176 Division US7658340B2 (en) 2003-07-29 2006-11-28 System and method for nanoparticle and nanoagglomerate fluidization

Publications (1)

Publication Number Publication Date
US20060086834A1 true US20060086834A1 (en) 2006-04-27

Family

ID=34278464

Family Applications (2)

Application Number Title Priority Date Filing Date
US10/900,868 Abandoned US20060086834A1 (en) 2003-07-29 2004-07-27 System and method for nanoparticle and nanoagglomerate fluidization
US11/605,176 Expired - Fee Related US7658340B2 (en) 2003-07-29 2006-11-28 System and method for nanoparticle and nanoagglomerate fluidization

Family Applications After (1)

Application Number Title Priority Date Filing Date
US11/605,176 Expired - Fee Related US7658340B2 (en) 2003-07-29 2006-11-28 System and method for nanoparticle and nanoagglomerate fluidization

Country Status (2)

Country Link
US (2) US20060086834A1 (fr)
WO (1) WO2005022667A2 (fr)

Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060243165A1 (en) * 2005-03-01 2006-11-02 Degussa Ag Colorant suspensions
US20070031319A1 (en) * 2005-08-04 2007-02-08 Degussa Ag Carbon material
US20070053846A1 (en) * 2005-08-31 2007-03-08 Dave Rajesh N Dry coating and downstream processing of cohesive powders
US20080003170A1 (en) * 2006-04-15 2008-01-03 Bayer Materialscience Ag Process for the production of carbon nanotubes in a fluidized bed
US20080179433A1 (en) * 2006-11-10 2008-07-31 New Jersey Institute Of Technology Fluidized Bed Systems And Methods Including Micro-Jet Flow
US20080219915A1 (en) * 2006-08-07 2008-09-11 Degussa Gmbh Carbon black, method of producing carbon black, and device for implementing the method
US20090077826A1 (en) * 2007-06-20 2009-03-26 New Jersey Institute Of Technology Systems And Methods For Reducing Electrostatic Charge In A Fluidized Bed
US20090155157A1 (en) * 2007-12-12 2009-06-18 Evonik Degussa Gmbh Process for aftertreating carbon black
US20090272078A1 (en) * 2006-11-13 2009-11-05 New Jersey Institute Of Technology Mixing and packing of particles
US20090293719A1 (en) * 2005-05-02 2009-12-03 Robert Pfeffer Fractal structured nanoagglomerates as filter media
WO2010004068A1 (fr) * 2008-07-10 2010-01-14 Universidad De Sevilla Fluidisation de poudres fines et ultrafines assistée par champs électriques oscillants
US20100071554A1 (en) * 2006-11-01 2010-03-25 New Jersey Institute Of Technology Aerogel-Based Filtration of Gas Phase Systems
US20100147187A1 (en) * 2008-12-12 2010-06-17 Evonik Degussa Gmbh Ink Jet Ink
WO2010087869A1 (fr) * 2009-01-30 2010-08-05 Imra America, Inc. Production de nanoparticules avec une ablation laser à impulsions ultracourtes à taux de répétition élevé dans des liquides
ES2347629A1 (es) * 2009-04-30 2010-11-02 Universidad De Sevilla Procedimiento asistido de adsorcion de dioxido de carbono.
US20100278713A1 (en) * 2007-08-21 2010-11-04 Semes Co., Ltd. Method of manufacturing a carbon nanotube, and apparatus and system for performing the method
US20100316556A1 (en) * 2007-04-18 2010-12-16 Fei Wei Multistage reactors for continuous production of carbon nanotubes
US20110193025A1 (en) * 2010-02-10 2011-08-11 Yuki Ichikawa Production of fine particles of functional ceramic by using pulsed laser
US20110192714A1 (en) * 2010-02-10 2011-08-11 Bing Liu Nanoparticle production in liquid with multiple-pulse ultrafast laser ablation
US20110192450A1 (en) * 2010-02-10 2011-08-11 Bing Liu Method for producing nanoparticle solutions based on pulsed laser ablation for fabrication of thin film solar cells
US20110207872A1 (en) * 2010-02-23 2011-08-25 Evonik Carbon Black Gmbh Carbon Black, Method for the Production Thereof, and Use Thereof
US8025726B1 (en) 2010-04-08 2011-09-27 Nalco Company Sulfur containing silica particle
US20110232531A1 (en) * 2008-11-27 2011-09-29 Evonik Carbon Black Gmbh Pigment Granulate, Method for Producing the Same and Use Thereof
US8333835B2 (en) 2010-04-08 2012-12-18 Nalco Company Sulfur containing silica particle
US8377194B2 (en) 2010-04-08 2013-02-19 Nalco Company Sulfur containing silica particle
US8409906B2 (en) 2010-10-25 2013-04-02 Imra America, Inc. Non-vacuum method for fabrication of a photovoltaic absorber layer
US8609046B2 (en) 2011-10-07 2013-12-17 Nalco Company Gas stream treatment process
US8748216B2 (en) 2010-10-25 2014-06-10 Imra America, Inc. Non-vacuum method for fabrication of a photovoltaic absorber layer
US8936772B2 (en) 2010-04-08 2015-01-20 Ecolab Usa Inc. Silica containing particle
US20150025505A1 (en) * 2008-07-09 2015-01-22 Massachusetts Institute Of Technology Bi-Directional Motion of a Lorentz-Force Actuated Needle-Free Injector (NFI)
CN104764631A (zh) * 2015-04-02 2015-07-08 青岛高远光电测控技术有限公司 一种便携式污染源稀释通道气溶胶采样装置及流化舱
US20150290135A1 (en) * 2012-11-16 2015-10-15 Merck Sharp & Dohme Corp. Process for making agglomerates using acoustic mixing technology
US20200002148A1 (en) * 2018-06-29 2020-01-02 Matsys Inc. Fluidized Powder Valve System
CN111286715A (zh) * 2018-12-07 2020-06-16 现代自动车株式会社 制备燃料电池用催化剂的方法和设备
US20200282359A1 (en) * 2019-03-08 2020-09-10 Arizona Board Of Regents On Behalf Of Arizona State University System and method for microjet and vibration-assisted fluidization of nanoparticles
US20210039975A1 (en) * 2018-03-13 2021-02-11 Natural Synergies Ltd An improved dewatering method and apparatus
WO2024040788A1 (fr) * 2022-08-23 2024-02-29 江苏科技大学 Procédé de traitement de détection d'agglomération se produisant dans un groupe de particules filamenteuses dans un lit fluidisé et système d'expérience

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8011424B2 (en) * 2005-06-09 2011-09-06 The United States Of America, As Represented By The Secretary Of The Navy System and method for convective heat transfer utilizing a particulate solution in a time varying field
GB0811856D0 (en) 2008-06-27 2008-07-30 Ucl Business Plc Magnetic microbubbles, methods of preparing them and their uses
FI124980B (fi) * 2010-01-20 2015-04-15 Hemeltron Ferromagneettisten hiukkasten mittausjärjestelmä
RU2493097C2 (ru) * 2010-06-15 2013-09-20 Общество с ограниченной ответственностью "НаноТехЦентр" Способ получения углеродных нанотрубок и реактор для их получения
ES2402611B1 (es) * 2011-10-25 2014-03-13 Universidad De Las Palmas De Gran Canaria Procedimiento, y aparato para su puesta en practica, para la condensacion de vapores de combustible y su recuperacion liquida que emplea medios vibratorios
AU2012332894A1 (en) * 2011-10-31 2014-05-08 Merck Sharp & Dohme Corp. Nano-suspension process
CN102872957B (zh) * 2012-09-29 2014-08-27 中国航天空气动力技术研究院 纳米级固体粉末制备装置
ES2498732B2 (es) * 2013-02-22 2015-02-02 Universidad De Sevilla Procedimiento de captura de CO2 por CaO a alta temperatura asistido por vibración acústica
WO2016011412A1 (fr) 2014-07-17 2016-01-21 Ada Technologies, Inc. Batteries à longévité extrême et haute densité d'énergie et leur procédé de fabrication et d'utilisation
WO2016209460A2 (fr) 2015-05-21 2016-12-29 Ada Technologies, Inc. Pseudocondensateurs hybrides à haute densité d'énergie et procédé de leur fabrication et utilisation
US11996564B2 (en) 2015-06-01 2024-05-28 Forge Nano Inc. Nano-engineered coatings for anode active materials, cathode active materials, and solid-state electrolytes and methods of making batteries containing nano-engineered coatings
US12401042B2 (en) 2015-06-01 2025-08-26 Forge Nano Inc. Nano-engineered coatings for anode active materials, cathode active materials, and solid-state electrolytes and methods of making batteries containing nano-engineered coatings
US12027661B2 (en) 2015-06-01 2024-07-02 Forge Nano Inc. Nano-engineered coatings for anode active materials, cathode active materials, and solid-state electrolytes and methods of making batteries containing nano-engineered coatings
US10692659B2 (en) 2015-07-31 2020-06-23 Ada Technologies, Inc. High energy and power electrochemical device and method of making and using same
ITUB20155667A1 (it) * 2015-11-17 2017-05-17 Consiglio Nazionale Ricerche Metodo ed apparato per la miscelazione di polveri costituite da particelle fini ed ultrafini
US11024846B2 (en) 2017-03-23 2021-06-01 Ada Technologies, Inc. High energy/power density, long cycle life, safe lithium-ion battery capable of long-term deep discharge/storage near zero volt and method of making and using the same
DE102018108346A1 (de) 2018-04-09 2019-10-10 Umicore Ag & Co. Kg Beschichteter Wandflussfilter
DE102018111246A1 (de) 2018-05-09 2019-11-14 Umicore Ag & Co. Kg Verfahren zum Beschichten eines Wandflussfilters
CN109046187B (zh) * 2018-10-09 2023-05-23 天津西敦津洋环保科技有限公司 一种高充气率的气固流化床反应器、实现在流化床中高充气率的方法及其应用
DE102018127953B4 (de) 2018-11-08 2025-03-20 Umicore Ag & Co. Kg Wandflussfilter mit hoher Filtrationseffizienz
DE102018127955A1 (de) 2018-11-08 2020-05-14 Umicore Ag & Co. Kg Katalytisch aktiver Partikelfilter mit hoher Filtrationseffizienz
DE102018127957A1 (de) 2018-11-08 2020-05-14 Umicore Ag & Co. Kg Partikelfilter mit mehreren Beschichtungen
CN116745459A (zh) 2020-11-30 2023-09-12 瓦克化学股份公司 制造含硅材料的方法
JP2024546565A (ja) 2021-12-20 2024-12-26 ワッカー ケミー アクチエンゲゼルシャフト 撹拌タンク反応器内でケイ素含有材料を製造するプロセス
KR20240033071A (ko) 2021-12-20 2024-03-12 와커 헤미 아게 교반층 반응기에서 가스 상과 미립자의 접촉
DE102023108230A1 (de) * 2023-03-30 2024-10-02 Rösler Holding Gmbh Vorrichtung zur Fluidisierung von Partikelschüttungen und Verfahren zum Betreiben derselben

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3439899A (en) * 1967-02-27 1969-04-22 Magneto Dynamics Inc Method for the production and control of fluidized beds
US3848363A (en) * 1973-02-20 1974-11-19 Minnesota Mining & Mfg Apparatus for treating objects with particles moved by magnetic force
US4720025A (en) * 1986-01-23 1988-01-19 Proizvodstvennoe Geologicheskoe Obiedinenie Tsentralnykh Raionov "Tsentrgeologiya" Feeder of loose materials
US5927621A (en) * 1997-07-10 1999-07-27 Xerox Corporation Particle size reduction process
US6039894A (en) * 1997-12-05 2000-03-21 Sri International Production of substantially monodisperse phosphor particles
US6471096B1 (en) * 1999-09-27 2002-10-29 Rajesh N. Dave Method and apparatus for magnetically mediated controlled powder discharge

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3439899A (en) * 1967-02-27 1969-04-22 Magneto Dynamics Inc Method for the production and control of fluidized beds
US3848363A (en) * 1973-02-20 1974-11-19 Minnesota Mining & Mfg Apparatus for treating objects with particles moved by magnetic force
US4720025A (en) * 1986-01-23 1988-01-19 Proizvodstvennoe Geologicheskoe Obiedinenie Tsentralnykh Raionov "Tsentrgeologiya" Feeder of loose materials
US5927621A (en) * 1997-07-10 1999-07-27 Xerox Corporation Particle size reduction process
US6039894A (en) * 1997-12-05 2000-03-21 Sri International Production of substantially monodisperse phosphor particles
US6471096B1 (en) * 1999-09-27 2002-10-29 Rajesh N. Dave Method and apparatus for magnetically mediated controlled powder discharge

Cited By (65)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060243165A1 (en) * 2005-03-01 2006-11-02 Degussa Ag Colorant suspensions
US20090293719A1 (en) * 2005-05-02 2009-12-03 Robert Pfeffer Fractal structured nanoagglomerates as filter media
US7645327B2 (en) 2005-05-02 2010-01-12 New Jersey Institute Of Technology Fractal structured nanoagglomerates as filter media
US20070031319A1 (en) * 2005-08-04 2007-02-08 Degussa Ag Carbon material
US20070053846A1 (en) * 2005-08-31 2007-03-08 Dave Rajesh N Dry coating and downstream processing of cohesive powders
US20080003170A1 (en) * 2006-04-15 2008-01-03 Bayer Materialscience Ag Process for the production of carbon nanotubes in a fluidized bed
US9050572B2 (en) * 2006-04-15 2015-06-09 Bayer Materialscience Ag Process for the production of carbon nanotubes in a fluidized bed
US8236274B2 (en) 2006-08-07 2012-08-07 Evonik Carbon Black Gmbh Carbon black, method of producing carbon black, and device for implementing the method
US20080219915A1 (en) * 2006-08-07 2008-09-11 Degussa Gmbh Carbon black, method of producing carbon black, and device for implementing the method
US20100071554A1 (en) * 2006-11-01 2010-03-25 New Jersey Institute Of Technology Aerogel-Based Filtration of Gas Phase Systems
US8632623B2 (en) 2006-11-01 2014-01-21 New Jersey Institute Of Technology Aerogel-based filtration of gas phase systems
US8550698B2 (en) 2006-11-10 2013-10-08 Orion Engineered Carbons Gmbh Fluidized mixing and blending of nanopowders with secondary gas flow
US8439283B2 (en) 2006-11-10 2013-05-14 New Jersey Institute Of Technology Fluidized bed systems and methods including micro-jet flow
US20080179433A1 (en) * 2006-11-10 2008-07-31 New Jersey Institute Of Technology Fluidized Bed Systems And Methods Including Micro-Jet Flow
US8118243B2 (en) 2006-11-10 2012-02-21 New Jersey Institute Of Technology Fluidized bed systems and methods including micro-jet flow
US20090272078A1 (en) * 2006-11-13 2009-11-05 New Jersey Institute Of Technology Mixing and packing of particles
US7806150B2 (en) * 2006-11-13 2010-10-05 New Jersey Institute Of Technology Mixing and packing of particles
US20100316556A1 (en) * 2007-04-18 2010-12-16 Fei Wei Multistage reactors for continuous production of carbon nanotubes
US7993594B2 (en) * 2007-04-18 2011-08-09 Tsinghua University Multistage reactors for continuous production of carbon nanotubes
US20090077826A1 (en) * 2007-06-20 2009-03-26 New Jersey Institute Of Technology Systems And Methods For Reducing Electrostatic Charge In A Fluidized Bed
US7905433B2 (en) * 2007-06-20 2011-03-15 New Jersey Institute Of Technology Systems and methods for reducing electrostatic charge in a fluidized bed
US20100278713A1 (en) * 2007-08-21 2010-11-04 Semes Co., Ltd. Method of manufacturing a carbon nanotube, and apparatus and system for performing the method
US8834632B2 (en) * 2007-08-21 2014-09-16 Korea Kumho Petrochemical Co., Ltd Apparatus and system for manufacturing a carbon nanotube
US8574527B2 (en) 2007-12-12 2013-11-05 Evonik Carbon Black Gmbh Process for aftertreating carbon black
US20090155157A1 (en) * 2007-12-12 2009-06-18 Evonik Degussa Gmbh Process for aftertreating carbon black
US10485928B2 (en) 2008-07-09 2019-11-26 Massachusetts Institute Of Technology Bi-directional motion of a Lorentz-force actuated needle-free injector (NFI)
US20150025505A1 (en) * 2008-07-09 2015-01-22 Massachusetts Institute Of Technology Bi-Directional Motion of a Lorentz-Force Actuated Needle-Free Injector (NFI)
US9789256B2 (en) * 2008-07-09 2017-10-17 Massachusetts Institute Of Technology Bi-directional motion of a lorentz-force actuated needle-free injector (NFI)
US11571519B2 (en) 2008-07-09 2023-02-07 Massachusetts Institute Of Technology Bi-directional motion of a Lorentz-force actuated needle-free injector (NFI)
ES2341934A1 (es) * 2008-07-10 2010-06-29 Universidad De Sevilla Fluidizacion de polvos finos y ultrafinos asistida por campos electriccos oscilantes.
WO2010004068A1 (fr) * 2008-07-10 2010-01-14 Universidad De Sevilla Fluidisation de poudres fines et ultrafines assistée par champs électriques oscillants
US20110232531A1 (en) * 2008-11-27 2011-09-29 Evonik Carbon Black Gmbh Pigment Granulate, Method for Producing the Same and Use Thereof
US8915998B2 (en) 2008-11-27 2014-12-23 Evonik Carbon Black Gmbh Pigment granulate, method for producing the same and use thereof
US20100147187A1 (en) * 2008-12-12 2010-06-17 Evonik Degussa Gmbh Ink Jet Ink
US8372191B2 (en) 2008-12-12 2013-02-12 Evonik Carbon Black Gmbh Ink jet ink
WO2010087869A1 (fr) * 2009-01-30 2010-08-05 Imra America, Inc. Production de nanoparticules avec une ablation laser à impulsions ultracourtes à taux de répétition élevé dans des liquides
US8246714B2 (en) 2009-01-30 2012-08-21 Imra America, Inc. Production of metal and metal-alloy nanoparticles with high repetition rate ultrafast pulsed laser ablation in liquids
CN102292159A (zh) * 2009-01-30 2011-12-21 Imra美国公司 在液体中用高重复频率超短脉冲激光烧蚀产生纳米颗粒
WO2010125210A1 (fr) * 2009-04-30 2010-11-04 Universidad De Sevilla Procédé assisté d'adsorption de dioxyde de carbone
ES2347629A1 (es) * 2009-04-30 2010-11-02 Universidad De Sevilla Procedimiento asistido de adsorcion de dioxido de carbono.
US8540173B2 (en) 2010-02-10 2013-09-24 Imra America, Inc. Production of fine particles of functional ceramic by using pulsed laser
US20110192714A1 (en) * 2010-02-10 2011-08-11 Bing Liu Nanoparticle production in liquid with multiple-pulse ultrafast laser ablation
US20110192450A1 (en) * 2010-02-10 2011-08-11 Bing Liu Method for producing nanoparticle solutions based on pulsed laser ablation for fabrication of thin film solar cells
US20110193025A1 (en) * 2010-02-10 2011-08-11 Yuki Ichikawa Production of fine particles of functional ceramic by using pulsed laser
US8858676B2 (en) 2010-02-10 2014-10-14 Imra America, Inc. Nanoparticle production in liquid with multiple-pulse ultrafast laser ablation
US20110207872A1 (en) * 2010-02-23 2011-08-25 Evonik Carbon Black Gmbh Carbon Black, Method for the Production Thereof, and Use Thereof
US8852739B2 (en) 2010-02-23 2014-10-07 Evonik Carbon Black Gmbh Carbon black, method for the production thereof, and use thereof
US8025726B1 (en) 2010-04-08 2011-09-27 Nalco Company Sulfur containing silica particle
US8936772B2 (en) 2010-04-08 2015-01-20 Ecolab Usa Inc. Silica containing particle
US8333835B2 (en) 2010-04-08 2012-12-18 Nalco Company Sulfur containing silica particle
US8377194B2 (en) 2010-04-08 2013-02-19 Nalco Company Sulfur containing silica particle
US8748216B2 (en) 2010-10-25 2014-06-10 Imra America, Inc. Non-vacuum method for fabrication of a photovoltaic absorber layer
US8409906B2 (en) 2010-10-25 2013-04-02 Imra America, Inc. Non-vacuum method for fabrication of a photovoltaic absorber layer
US8961821B2 (en) 2011-10-07 2015-02-24 Ecolab Usa Inc. Gas stream treatment process
US8609046B2 (en) 2011-10-07 2013-12-17 Nalco Company Gas stream treatment process
US20150290135A1 (en) * 2012-11-16 2015-10-15 Merck Sharp & Dohme Corp. Process for making agglomerates using acoustic mixing technology
CN104764631A (zh) * 2015-04-02 2015-07-08 青岛高远光电测控技术有限公司 一种便携式污染源稀释通道气溶胶采样装置及流化舱
US20210039975A1 (en) * 2018-03-13 2021-02-11 Natural Synergies Ltd An improved dewatering method and apparatus
US20200002148A1 (en) * 2018-06-29 2020-01-02 Matsys Inc. Fluidized Powder Valve System
US11027959B2 (en) * 2018-06-29 2021-06-08 Matsys Inc. Fluidized powder valve system
CN111286715A (zh) * 2018-12-07 2020-06-16 现代自动车株式会社 制备燃料电池用催化剂的方法和设备
US11433368B2 (en) * 2018-12-07 2022-09-06 Hyundai Motor Company Method and apparatus of preparing catalyst for fuel cell
CN111286715B (zh) * 2018-12-07 2023-10-10 现代自动车株式会社 制备燃料电池用催化剂的方法和设备
US20200282359A1 (en) * 2019-03-08 2020-09-10 Arizona Board Of Regents On Behalf Of Arizona State University System and method for microjet and vibration-assisted fluidization of nanoparticles
WO2024040788A1 (fr) * 2022-08-23 2024-02-29 江苏科技大学 Procédé de traitement de détection d'agglomération se produisant dans un groupe de particules filamenteuses dans un lit fluidisé et système d'expérience

Also Published As

Publication number Publication date
WO2005022667A3 (fr) 2006-03-30
US20070108320A1 (en) 2007-05-17
US7658340B2 (en) 2010-02-09
WO2005022667A2 (fr) 2005-03-10

Similar Documents

Publication Publication Date Title
US7658340B2 (en) System and method for nanoparticle and nanoagglomerate fluidization
Shabanian et al. Fluidization of ultrafine powders
Zhu et al. Sound assisted fluidization of nanoparticle agglomerates
Zhu et al. Gas fluidization characteristics of nanoparticle agglomerates
Chen et al. Fluidization of coated group C powders
Qian et al. Gas–solid fluidization in a centrifugal field
KR101443166B1 (ko) 유동층 시스템 및 2차 가스 유동을 포함하는 방법
Kaliyaperumal et al. Effects of acoustic vibration on nano and sub-micron powders fluidization
Millán Fluidization of fine powders: cohesive versus dynamical aggregation
Quevedo et al. Fluidization enhancement of agglomerates of metal oxide nanopowders by microjets
Kaliyaperumal et al. Fluidization of nano and sub-micron powders using mechanical vibration
Biswas et al. Numerical simulations of air-driven granular separation
Levy et al. Combined effects of mechanical and acoustic vibrations on fluidization of cohesive powders
Valverde Acoustic streaming in gas-fluidized beds of small particles
An et al. Enhanced fluidization of nanosized TiO2 by a microjet and vibration assisted (MVA) method
WO2019135843A1 (fr) Particules à utiliser dans des procédés d'ondes stationnaires acoustiques
Mawatari et al. Flow pattern transition of fine cohesive powders in a gas-solid fluidized bed under mechanical vibrating conditions
US6471096B1 (en) Method and apparatus for magnetically mediated controlled powder discharge
Karimi et al. Enhancing the fluidization quality of nanoparticles using external fields
Mawatari et al. Comparison of three vibrational modes (twist, vertical and horizontal) for fluidization of fine particles
Quintanilla et al. Nanofluidization as affected by vibration and electrostatic fields
CN108348873B (zh) 通过低温流体使粉末混合并产生振动的设备
Scicolone et al. Fluidization and mixing of nanoparticle agglomerates assisted via magnetic impaction
Thornton Powders & Grains 93
Espin et al. Electromechanics of fluidized beds of nanoparticles

Legal Events

Date Code Title Description
AS Assignment

Owner name: NEW JERSEY INSTITUTE OF TECHNOLOGY, NEW JERSEY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PFEFFER, ROBERT;NAM, CAROLINE H.;DAVE, RAJESH N.;AND OTHERS;REEL/FRAME:016387/0171;SIGNING DATES FROM 20050308 TO 20050310

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION