Patent Description:
At least one aspect is directed to a continuous acoustic chemical microreactor system characterized according to claim <NUM>.

In some implementations, the acoustic agitator can be configured to agitate the continuous process vessel with an acceleration greater than <NUM>.

In some implementations, the elongated tube can be at least <NUM> long.

In some implementations, the continuous process vessel can include a coolant inlet configured to receive a cooling fluid, an interstitial region within the continuous process vessel and surrounding the elongated tube, and a coolant outlet for discharging the cooling fluid from the interstitial region. The interstitial region can be configured to receive the cooling fluid and bring it into contact with an outer surface of the elongated tube.

In some implementations, the continuous process vessel can include a heater inlet configured to receive a heating fluid, an interstitial region within the continuous process vessel and surrounding the elongated tube, and a heater outlet for discharging the heating fluid from the interstitial region. The interstitial region can be configured to receive the heating fluid and bring it into contact with an outer surface of the elongated tube.

In some implementations, the inlet can be configured to receive a transport gas.

In some implementations, the system can be configured to operate at mechanical resonance.

In some implementations, the system can include a second reactant inlet coupled to the elongated tube at a point between the first end and the second end and configured to receive a midstream reactant and introduce it into the elongated tube.

In some implementations, the inner surface of the elongated tube can have a cross section that is substantially circular.

In some implementations, the inner surface of the elongated tube can have a cross section that is substantially ovular.

In some implementations, the inner surface of the elongated tube can have a cross section that is substantially rectangular.

In some implementations, the inner surface of the elongated tube can have a cross section that is substantially square.

In some implementations, the inner surface of the elongated tube can have a cross section that is substantially triangular.

In some implementations, the inner surface of the elongated tube can be smooth.

In some implementations, the inner surface of the elongated tube can be rough.

In some implementations, the inner surface of the elongated tube can be coated with a catalyst.

At least one aspect is directed to a method of continuously processing a combination of materials in a chemical microreactor according to claim <NUM>.

In some implementations, the method can include introducing, via a coolant inlet, a cooling fluid into an interstitial region within the continuous process vessel and surrounding the elongated tube, and discharging, via a coolant outlet, the cooling fluid from the interstitial region. The interstitial region can be configured to receive the cooling fluid and bring it into contact with an outer surface of the elongated tube.

In some implementations, the method can include introducing, via a heater inlet, a heating fluid into an interstitial region within the continuous process vessel and surrounding the elongated tube, and discharging, via a heater outlet, the heating fluid from the interstitial region. The interstitial region can be configured to receive the heating fluid and bring it into contact with an outer surface of the elongated tube.

In some implementations, the method can include introducing a midstream reactant into the elongated tube via a second reactant inlet coupled to the elongated tube at a point between the first end and the second end.

In some implementations, the method can include introducing a transport gas into the reactant inlet. In some implementations, the transport gas is introduced to maintain a gas fraction in the elongated tube greater than <NUM>% and less than <NUM>%.

In some implementations, the method can include agitating the continuous process vessel with an acceleration greater than <NUM>.

In some implementations, the method can include agitating the continuous process vessel at a mechanical resonance of the combined acoustic agitator and continuous process vessel system.

A continuous processing system is described herein that has distinctive features that separate it from other mixers currently available, such as laminar regime mixers. The continuous processing system operates at mechanical resonance that enables large vibrational amplitudes at low-frequencies, in the range of between about <NUM> to about <NUM>. In some implementations, the system operates at about <NUM>. These large amplitudes create a strong sinusoidal acoustic field inside of a mixing reactor or a continuous process vessel, which provides efficient and intense mixing and reacting. Additionally, the displacement of plates or other structures disposed within the continuous process vessel can impose large acceleration forces on the materials to increase the efficiency and intensity of the mixing and reacting. Low-frequency, high-intensity acoustic energy is used to create a near uniform shear field throughout substantially the entire continuous process vessel, which results in rapid fluidization, reaction and/or dispersion of materials. Operation at such high accelerations puts large mechanical stresses into the components of the process vessel, but, as the process vessel is oscillated at or near the resonance of the resonant system, the operation of the device can be quite efficient. Because of these features, the reliability of the equipment at extreme operating conditions is substantially improved and enables the technology to be scaled. Such systems are applicable to a wide variety of reactions and mixing applications.

Low frequency acoustic agitation (LFAA) differs from ultrasonic mixing in that the frequency of acoustic energy is orders of magnitude lower. Most ultrasonic (><NUM>) energies are fully absorbed by the material immediately in front of the ultrasonic transducer. LFAA mixing utilizes acoustic energy, in some implementations nominally at <NUM> (though at other frequencies less than <NUM> in other implementations), that fully penetrates substantially the entire contents of a process vessel. The acoustic energy produced by the LFAA can range from a g-force of a few g's to hundreds of g's. Unlike impeller agitation, which mixes by inducing bulk flow with eddies generated at the impeller edges, the LFAA mixing occurs on a microscale substantially uniformly throughout the mixing volume. Additional interactions with the vessel walls cause beneficial bulk flow. Sound waves radiating from the reactor plates are attenuated, scattered, reflected, or propagated as they transmit through a non-homogeneous media. Attenuation creates an energy gradient which corresponds to a body force onto the media being mixed. This force induces macro flow in the media referred to as acoustic streaming. The acoustic streaming, along with the interaction between the media and the mixing vessel, results in the micro-mixing of the media. Because the acoustic field forms throughout the process vessel there are low and in many cases no mixing dead zones and the shear may be near evenly distributed throughout the process vessel once the materials are fluidized. The scattering and reflected waves also create body forces on sub-elements of the media with volumes of different density. Depending on the density ratio and material viscosity, these body forces can be significant or negligible in performing micro mixing. In some implementation, both the top and the bottom surfaces of each structure within a process vessel, impart acoustic energy on the mixture as it travels through each level of the vessel.

The process of continuous acoustic mixing can be extended to microreactors. A primary feature of microreactors is their small size, which can allow for sufficient rates of heat transfer when conducting highly exothermic reactions. In the case of a continuous acoustic microreactor, the reaction vessel can include an elongated tube, conduit, channel, or duct for conveying the reactants and for imparting acoustic energy upon them to promote the desired reaction. The elongated tube can have various cross sections including, for example and without limitation, circular, semi-circular, elliptical, rectangular, or polygonal. The elongated tube can include an inlet for receiving one or more reactants, and an outlet for discharging a product. The elongated tube can be coiled, wrapped, or folded, etc. within the continuous process vessel to increase its length beyond the dimensions of the continuous process vessel. An acoustic agitator can agitate the continuous process vessel at frequencies and accelerations sufficient to overcome adhesion and surface tension effects of reactants with an inner surface of the elongated tube. In some implementations, a transport gas can be introduced into the tube to enhance agitation. The transport gas can be reactive or inert. In some implementations, the continuous process vessel can include an interstitial region within the continuous process vessel and surrounding the elongated tube. The interstitial region can receive a cooling fluid or heating fluid and bring it into contact with an outer surface of the elongated tube so as to continuously transfer heat out of or into the elongated tube. In some implementations, the elongated tube can include a second inlet along its length for introducing a midstream reactant. The midstream reactant can react with a product of an initial reaction that occurred upstream in the elongated tube. The midstream reactant can also or alternatively feed a reaction that requires a shorter reaction/residence time than the reaction among the reactants introduced at the first inlet. Additional midstream inlets can be provided to allow for further midstream reactants to be added at different points along the elongated tube.

The continuous acoustic chemical microreactors of the present disclosure are applicable for a broad range of chemical reactions to include, for example and without limitation, synthesis reactions, decomposition reactions, single displacement reactions, double displacement reactions, precipitation, acid-base neutralization, organic reactions, reduction-oxidation reactions, as well as reactions that produce precipitating solids and/or utilize solids as reagents.

<FIG> shows an example of a continuous processing system 10a. The continuous processing system 10a can include an acoustic agitator 11a and a continuous process vessel 18a. The process vessel 18a can include inlets 2a through 2e (collectively "inlets <NUM>") configured for introducing at least one process ingredient, a plurality of plates 22a configured for directing a flow of the process ingredients through the process vessel 18a, and which are capable of transferring acoustic energy generated by the acoustic agitator 11a into the process ingredients, an outlet 26a for discharging a product of the process ingredients subsequent to the process ingredients passing through a portion of the process vessel 18a while being exposed to the acoustic energy, and a fastener 30a for removably coupling the process vessel 18a to the acoustic agitator 11a. The shape of the process vessel 18a can be configured in a variety of different implementations and can include many different components, as will be discussed in greater detail below. The different implementations of the process vessel 18a can support a variety of processes, for example mixing, combining, drying, coating, segregating, and reacting of process ingredients.

<FIG> shows an illustrative implementation of a continuous processing system 10a. In <FIG>, the processing system 10a includes a process vessel 18a coupled to an acoustic agitator 11a. The acoustic agitator 11a can include an electrical cabinet 12a and a resonance assembly 14a. The acoustic agitator 11a can be a RAM® Mixer (RAM), such as those available from Resodyn Acoustic Mixers (Butte, Montana). The processing system 10a further includes multiple conduits 2a to deliver the materials to the processing system and multiple hoppers 8a to hold the materials prior to being introduced into the process vessel 18a. The conduits 2a can be any type of pipe, conduit or hose used for delivering materials, such as a solid, gas or fluid. The hoppers 8a can have any type of closed geometric figure with a hollow body to hold or transfer materials into the process vessel 18a, for example a container, barrel, funnel, or vat. The conduits 2a and hoppers 8a can be coupled to the processing system 10a by a support frame 9a. The support frame 9a can be an open structure to connect and hold the components of the processing system 10a together. The support frame <NUM> can be coupled to the acoustic agitator 11a, the process vessel 18a, and the hoppers 8a. The support frame 9a can be made up of multiple sections.

<FIG> further shows a cutaway view of one implementation of the process vessel 18a. The process vessel 18a can include multiple levels, each of the levels can include at least one of a plurality of plates 22a. The plates 22a can be configured to direct materials through the process vessel 18a. The plates 22a can be made up of many different materials, for example and without limitation, stainless steel, aluminum, and carbon steel. In some implementations, the plates 22a can have a stiffness factor of about <NUM>,<NUM> lbf/in (565N. m) or greater. In other implementations, the materials can have other stiffness factor values. The process vessel 18a can include a heated plate 6a, a cooling plate 6b, a plurality of inlets 2a - 2e used for conduits to introduce different process ingredients (including, without limitation, mixture constituents, coatings, reactants, and/or buffers) at different levels of the process vessel 18a, and an exit port <NUM> to discharge a product of the processing system 10a. The inlets 2a - 2e can be positioned along the top and/or any side of the process vessel 18a to introduce materials. The exit port <NUM> can be positioned along a bottom portion of the process vessel 18a.

In some implementations, the process ingredients reacting and mixing in the process vessel 18a can form a fluidized bed inside the process vessel 18a. The processing system 10a is well suited to create fluidized beds, with material particle sizes that range from nano-sized particles to particles the size of tablets. Because the fluidization is formed by vibration, processing system 10a can fluidize nano-particles and all sizes up to tablets. The fluidized bed can be created at each level of the process vessel 18a.

<FIG> shows a cutaway perspective view of a continuous process vessel 18j, according to an illustrative implementation. Instead of the process vessel 18j being configured with plates 22a, as shown in <FIG>, the process vessel 18j includes coiled pipes <NUM> for processing the materials. The process vessel 18j includes an inlet 20j, the coiled pipes <NUM> and an outlet 26j. Materials can be introduced to the process vessel 18j through the inlet 20j and pass through the process vessel 18j through the coiled pipes <NUM>. The coiled pipes can be configured in a helix or spiral formation inside the process vessel 18j. In some implementations, the process vessel 18j can include compact coiled pipes to save space and maximize length of the reaction, and/or mixing process. The compact coiled pipes can allow for more coiled pipe length in the process vessel 18j to allow the materials to be in process longer. Once the materials have been substantially reacted, they can be discharged through the outlet 26j.

In some implementations, the process vessel <NUM> can be a microreactor. A primary feature of microreactors is their small size, which can allow for sufficient rates of heat transfer when conducting highly exothermic reactions. <FIG> shows an example process vessel 18w suitable for use as a continuous acoustic chemical microreactor, according to an illustrative implementation. The process vessel 18w includes an elongated tube 70w coupled at a first end to a reactant inlet 20w and at a second end to a product outlet 26w. The reactant inlet 20w can receive one or more reactants and introduce them in to the elongated tube 70w. The outlet 26w can discharge a product of the reactants following a reaction among the reactants in the elongated tube 70w. In some implementations, the inlet 20w can be configured to additionally receive a transport gas for improving mixing action within the elongated tube 70w.

The elongated tube 70w can be a pipe, tube, conduit, or duct suitable for conveying liquid, solid, gas, or plasma reactants. The elongated tube 70w can be sufficiently robust to handle large alternating accelerations induced externally while reactants impact the inner surfaces. The accelerations imparted by the acoustic agitator reach a g-force of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more. The elongated tube 70w can have dimensions and properties suitable for acting as a microreactor for highly exothermic reactions. For example, its internal volume can be kept relatively small and its thermal conductivity relatively high. The elongated tube 70w has an inner surface having a hydraulic diameter of less than <NUM>. The elongated tube 70w can be made of materials that will not react, or react only little, when in contact with certain reactants or products. For example and without limitation, the elongated tube 70w can be made of a glass, metal, ceramic, or polymer. Appropriate metals may include stainless steel, molybdenum, titanium, or monel. Other suitable elongated tubes 70w can include combinations of materials, such as a polymer- or glass-lined metals. In some implementations, it may be beneficial for the elongated tube 70w to have good thermal conductivity for conducting heat away from exothermic reactions, or heat into endothermic reactions. For example and without limitation, in some implementations the elongated tube 70w can have a thermal conductivity greater than <NUM> watts per meter-kelvin, roughly that of some stainless steel alloys. In some implementations, the inner surface of the elongated tube 70w can be coated with a catalyst. Such catalysts can include, for example and without limitation, metals, metal oxides, non-metals, ceramics, polymers, and nanoparticles or nanostructures.

To ensure adequate residence time for reactions, the elongated tube 70w can be relatively long relative to its width. In some implementations, the elongated tube 70w is at least <NUM> long. In some implementations, the elongated tube 70w can be up to <NUM> long. In some implementations, the elongated tube 70w can be between <NUM> and <NUM> long. The elongated tube 70w can have various shapes. The elongated tube 70w can take the shape of a helix, spiral, series of spirals, or any other folded or wrapped shape suitable for fitting its entire length within the process vessel 18w. The elongated tube 70w can have various cross-sectional shapes. In some implementations, the elongated tube 70w can have inner and outer surfaces having a circular, elliptical, or polygonal cross section. In some implementations, the inner surface of the elongated tube 70w can be smooth around its perimeter and/or along its length in the sense that the inner surface is free of undulations or structures that would disrupt laminar flow through when the elongated tube 70w is stationary. In some implementations, the outer surface of the elongated tube 70w can include fins or other protrusions to increase its surface area and promote heat conduction.

The process vessel 18w is coupled to the acoustic agitator 11a, which can agitate the process vessel 18w along an oscillation axis. The oscillation axis may be aligned vertically; i.e., parallel with the direction of gravitational pull. When the process vessel 18w is agitated, an inner surface of the elongated tube 70w can impart acoustic energy on the reactants by accelerating the reactants in alternating upward and downward directions along the oscillation axis. The elongated tube 70w can be aligned normal to the oscillation axis such that the upper and lower portions of the inside surface agitate the reactants when the elongated tube 70w is oscillated along the oscillation axis. In some implementations, the elongated tube 70w can be positioned such that it is at, or close to, a right angle with respect to the oscillation axis. In some implementations, the elongated tube 70w can be positioned such that it is at an angle of <NUM> to <NUM>° with respect to the oscillation axis such that it is angled downward in the direction of desired bulk flow. In some implementations, the elongated tube 70w can be positioned such that it is at an angle of <NUM> to <NUM>° with respect to the oscillation axis such that it is angled downward in the direction of desired bulk flow. In some implementations, the elongated tube 70w can be positioned such that it is at an angle of <NUM> to <NUM>° with respect to the oscillation axis such that it is angled downward in the direction of desired bulk flow. The acoustic agitator <NUM> can be powerful enough to agitate the process vessel 18w at high rates of acceleration. In some implementations, the acoustic agitator is configured to agitate the continuous process vessel with an acceleration greater than <NUM>. In some implementations, the acoustic agitator and the continuous process vessel can operate at a mechanical resonance of the acoustic agitator-continuous process vessel system. Operating at a mechanical resonance allows for energy efficient operation of the acoustic agitator under highly kinetic conditions. The acoustic agitator agitates the continuous process vessel at a frequency greater than <NUM> and less than <NUM>.

In some implementations, the process vessel 18w can include features for removing heat from, or adding heat to, the reaction chamber; i.e., the elongated tube 70w. For example, the process vessel 18w can include a second inlet 42w for receiving a fluid, such as a cooling fluid or a heating fluid, a cavity or interstitial region 52w within the process vessel 18w and surrounding the elongated tube 70w, and an outlet 43w for discharging the fluid from the interstitial region 52w. Fluid within the interstitial region 52w can circulate around, and come into contact with, an outer surface of the elongated tube 70w to remove heat from an exothermic reaction occurring within the elongated tube 70w, or provide heat to an endothermic reaction occurring within the elongated tube 70w. Circulation of the fluid can occur through external pumping and/or through the agitation of the process vessel 18w. In some implementations, the fluid can flow through the interstitial region 52w in substantially the same direction as reactants flowing through the elongated tube 70w. In some implementations, the fluid can flow through the interstitial region 52w in a direction substantially counter to the direction of the flow of reactants flowing through the elongated tube 70w.

In some implementations, the process vessel <NUM> can include a second inlet for receiving a midstream reagent. The second inlet can introduce the midstream reagent into a midpoint (not necessarily the exact geometric midpoint) somewhere along the elongated tube. A midstream reagent can react with a product of an initial reaction occurring in the portion of the elongated tube upstream from the second inlet or the midstream reagent may be added after some reaction has already taken place because it reacts faster than the other reactants. <FIG> shows an example process vessel 18x having a second inlet for receiving a midstream reactant, and suitable for use as a continuous acoustic chemical microreactor, according to an illustrative implementation. The process vessel 18x includes an elongated tube 70x having a first portion 71x and a second portion 72x coupled in series. The properties of the elongated tube 70x can be similar to those of the elongated tube 70w described previously. The elongated tube 70x is coupled at a first end to a reactant inlet 20x and at a second end to a product outlet 26x. The reactant inlet 20x can receive one or more reactants and introduce them in to the first end of the elongated tube 70x. The outlet 26x can discharge a product of the reactants and midstream reactants following a reaction in the elongated tube 70x. The process vessel 18x includes a second inlet 21x coupled to the elongated tube 70x at a point where the first portion 71x and the second portion 72x meet. The second inlet 21x can receive one or more midstream reactants and introduce them into the second portion 71x. Additional midstream inlets can be provided to allow for further midstream reactants to be added at different points along the elongated tube 70x.

The process vessel 18x can be coupled to the acoustic agitator <NUM>, which can agitate the process vessel 18x along an oscillation axis. When the process vessel 18x is agitated, an inner surface of the elongated tube 70x can impart acoustic energy on the reactants and midstream reactants by accelerating the reactants and midstream reactants in alternating upward and downward directions with respect to the oscillation axis.

In some implementations, the process vessel 18x can include features for removing heat from, or adding heat to, the reaction chamber; i.e., the elongated tube 70x. For example, the process vessel 18x can include a second inlet 42x for receiving a fluid, such as a cooling fluid or a heating fluid, a cavity or interstitial region 52x within the process vessel 18x and surrounding the elongated tube 70x, and an outlet 43x for discharging the cooling fluid from the interstitial region 52x. Fluid within the interstitial region 52x can circulate around and come into contact with an outer surface of the elongated tube 70x to remove heat from an exothermic reaction occurring within the elongated tube 70x, or provide heat to an endothermic reaction occurring within the elongated tube 70x. Circulation of the fluid can occur through external pumping and/or through the agitation of the process vessel 18x. In some implementations, the fluid can flow through the interstitial region 52x in substantially the same direction as reactants flowing through the elongated tube 70x. In some implementations, the fluid can flow through the interstitial region 52x in a direction substantially counter to the direction of the flow of reactants flowing through the elongated tube 70x. <FIG>, described below show example experimental setups of continuous acoustic chemical microreactors, according to an illustrative implementation.

<FIG> shows an example experimental setup of a continuous acoustic chemical microreactor <NUM>, according to an illustrative implementation. The microreactor <NUM> includes a first inlet <NUM> for receiving a first liquid (Liquid <NUM>), a second inlet <NUM> for receiving a second liquid (Liquid <NUM>), and a gas inlet <NUM> for receiving a transport gas or gas reactant. In some implementations, the first inlet <NUM> and second inlet <NUM> can receive additional liquid or solid reagents or reactants. An elongated tube <NUM> coupled to the inlets receives the reactants and gas and serves as a reaction chamber. An outlet <NUM> coupled to the elongated tube <NUM> receives a product of the reaction from the elongated tube <NUM> and discharges it from the microreactor <NUM> so it can be analyzed. The microreactor <NUM> is mounted on an acoustic agitator such as the acoustic agitator 11a previously described.

The microreactor <NUM> was used for a series of tests to qualitatively gauge its performance under different amplitudes of agitation. For this series of tests, the liquid flow was ~<NUM>/min and the gas volume fraction was ~<NUM>%. Acceleration of the microreactor <NUM> was varied from <NUM> to <NUM> in <NUM> increments. It was observed that the mixing process within the elongated tube <NUM> varied as a function of the acceleration applied. It was deemed appropriate to classify the mixing characteristics into two general regimes: (<NUM>) a compressive gas mix regime and (<NUM>) a highly chaotic splitting and combining regime. The regime change varies in accordance with acceleration. At accelerations below ~<NUM> bubbles maintain some structure and pulse as they move along the elongated tube <NUM>, with very small pulsations at <NUM> and increasing up to ~<NUM>.

Above ~<NUM>, a transition occurs, and the bubble structure breaks down. Sheets and droplets of liquid become more dispersed into the continuous phase of gas within the tube. The gas-liquid interfacial area increases and the mixing becomes chaotic in form. The chaotic features of the mix increase as the acceleration is increased above <NUM>, become fully formed at ~<NUM>, and increase in intensity up to ~<NUM>, where it is hard to discern addition chaotic mixing features from ~<NUM> to the maximum tested operating condition of <NUM>.

Throughout the chaotic mixing regime the fluid appears to be propelled across the diameter of the elongated tube <NUM> from one portion of the inner surface to the other, corresponding to the agitating motion of the elongated tube <NUM> as it is vibrated by the acoustic agitator. The mixing regime showed a lack of bubbly structure and more of a froth-like mixing regime over <NUM> as noted above.

A certain proportion of gas within the microreactor <NUM>-i.e., the gas-volume fraction-can promote high levels of mixing. The gas can be of any type desired, ranging from reactive to inert. Suitable gases can include, without limitation, air, nitrogen, oxygen, argon, hydrogen, helium, carbon dioxide, neon, fluorine, chlorine, xenon, or other vapors, or combinations thereof.

<FIG> shows an example experimental setup of a continuous acoustic chemical microreactor <NUM>, according to an illustrative implementation. The microreactor <NUM> includes a first inlet <NUM> for receiving a first liquid, in this case water, and a gas inlet <NUM> for receiving a transport gas or gas reactant, in this case nitrogen. An elongated tube <NUM> coupled to the inlets receives the water and nitrogen and serves as a reaction chamber. An outlet <NUM> coupled to the elongated tube <NUM> receives a product of the reaction from the elongated tube <NUM> and discharges it from the microreactor so it can be analyzed. The entire apparatus is mounted on an acoustic agitator such as the acoustic agitator 11a previously described.

The microreactor <NUM> was used for a series of tests to measure gas-liquid mass transport in a small diameter tube as a means to establish the feasibility of using acoustic agitator <NUM> to enhance microreactor productivity. Water was fed into the elongated tube <NUM> via the first inlet <NUM>, as nitrogen was fed into the elongated tube <NUM> via the gas inlet <NUM>. The acoustic agitator agitated the elongated tube <NUM> along the oscillation axis shown in the diagram, and the dissolved oxygen was measured in the product discharged from the outlet <NUM>. The dissolved oxygen readings were taken every <NUM> seconds. The rate of nitrogen replacement of the dissolved oxygen in the water was used in Equation <NUM> below to determine the volumetric mass transfer coefficient (kLa) at acceleration (g) levels of <NUM>, <NUM><NUM>, <NUM> and <NUM>. (Pictures in <FIG>, above, illustrated the relative gas-liquid mixing conditions at each of these accelerations.

<FIG> shows example results <NUM> of experiments conducted with the continuous acoustic chemical microreactor shown in <FIG> at different inlet gas flows and accelerations. The data depicted in <FIG> shows kLa as a function of vertical tube acceleration for acceleration levels of <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, at nitrogen gas fractions of <NUM>, <NUM>, <NUM>, and <NUM>%. The results <NUM> show measured kLa values exceeding even the highest Continuous Stirred Tank Reactor (CSTR) kLa values found in the literature.

<FIG> shows example results <NUM> of experiments conducted with the continuous acoustic chemical microreactor shown in <FIG> versus a Corning Advances-Flow™ Reactor at different inlet gas flows and accelerations. <FIG> shows a comparison of the microreactor <NUM> (RAM) kLa values for the <NUM>% gas and <NUM>% gas conditions in comparison to results published by Corning for their microreactor, called the Advanced-Flow™ Reactor (AFR) at comparable gas flow rates. In both situations the microreactor <NUM>La values exceed the reported AFR values at acceleration levels of ~<NUM> and greater. As shown in Table <NUM> below, the gas-liquid mass transport coefficient for the microreactor <NUM> was substantially better than that for the Corning AFR despite having a shorter residence time in the reaction zone.

The microreactor <NUM> kLa need not depend upon turbulence developed by flow through the tubes. The microreactor <NUM> mixing can depend solely or primarily upon the acceleration and is therefore independent of the Reynolds number. This finding means that the microreactor <NUM> can have a wide flow turn-up and turn-down window and not require turbulent flow through the microreactor channels.

<FIG> shows example results <NUM> of experiments conducted with a continuous acoustic chemical microreactor measuring mixing time versus acceleration. The experiment is based on the iodide/iodate chemical test reaction, also called the Villermaux-Dushman method, which uses parallel competing reactions having different speeds. Briefly, good mixing favors the faster reaction, and the presence of an undesirable byproduct can be measured to quantify the effectiveness of mixing. The experiment was conducted to compare the effectiveness of a continuous acoustic chemical microreactor of the present disclosure with the Corning AFR™ unit previously described.

The results <NUM> of the Villermaux-Dushman method test are shown in <FIG>. The results <NUM> show that, at <NUM>, the continuous acoustic chemical microreactor can achieve a mixing time of <NUM>, as compared to <NUM>-<NUM> as listed in the data published for the Corning AFR™ for the same reaction.

<FIG> shows example results <NUM> of experiments conducted with a continuous acoustic chemical microreactor measuring mix quality versus acceleration. The results <NUM> show that at <NUM>, the continuous acoustic chemical microreactor can achieve a mix quality of <NUM>%, as compared to <NUM>% as listed in the data published for the Corning AFR™ for the same reaction. The results <NUM> and <NUM> show that the continuous acoustic chemical microreactor can outperform the Corning AFR™ in both mixing time and quality at and above <NUM> of acceleration.

An example method of operation of the continuous processing system 10a will now be described with reference to <FIG>.

<FIG> is a flowchart of an example method <NUM> method of continuously processing a combination of materials in a chemical microreactor, according to an illustrative implementation. The method <NUM> can be performed using a continuous acoustic mixer such as the continuous processing system <NUM> including, for example, one of the process vessels 18j, 18w, or 18x previously described. The method <NUM> includes introducing, via a reactant inlet, one or more reactants into an elongated tube coupled at a first end to the reactant inlet and configured to receive the reactants from the reactant inlet (stage <NUM>). The method <NUM> includes agitating, using an acoustic agitator coupled to the continuous process vessel, the continuous process vessel along the oscillation axis such that the inner surface of the elongated tube accelerates the one or more reactants in alternating upward and downward directions with respect to the oscillation axis (stage <NUM>). The method <NUM> includes discharging, from a product outlet coupled to a second end of the elongated tube, a product of a chemical reaction from the continuous process vessel (stage <NUM>).

The method <NUM> includes introducing, via a reactant inlet, one or more reactants into an elongated tube coupled at a first end to the reactant inlet and configured to receive the reactants from the reactant inlet (stage <NUM>). To ensure adequate heat removal for highly exothermic reactions, the elongated tube, such as elongated tube <NUM>, 70w, or 70x, can be thermally conductive and have a relatively small cross-sectional area such that the surface area-to-volume ratio remains relatively high to promote rapid conduction of heat away from the elongated tube. The elongated tube has an inner surface having a hydraulic diameter of less than <NUM>. In some implementations, the method <NUM> can include introducing a transport gas into the reactant inlet simultaneously or sequentially with the reactants. The transport gas can aid mixing by allowing liquid reactants to froth and mix more vigorously and achieve a chaotic, frothy state. The transport gas can be reactive or inert. In some implementations, a certain gas-volume fraction can be maintained for increased rates of mixing. For example, transport gas can be introduced to maintain a gas-volume fraction of at least <NUM>%.

The method <NUM> includes agitating, using an acoustic agitator coupled to the continuous process vessel, the continuous process vessel along the oscillation axis such that the inner surface of the elongated tube accelerates the one or more reactants in alternating upward and downward directions with respect to the oscillation axis (stage <NUM>). In some implementations, the acoustic agitator can agitate the continuous process vessel at high rates of acceleration. For example, in some implementations, the acoustic agitator can agitate the continuous process vessel at an acceleration greater than <NUM> and up to <NUM>. Accelerations greater than <NUM> can cause breakdown of the bubble structure of liquid reactants and transport gas and increase the gas-liquid interfacial area. Throughout the chaotic mixing regime, the reactants will be propelled across the cross section of the elongated tube from one wall to the other, corresponding to the agitating motion of the process vessel as it is vibrated by the acoustic agitator. In some implementations, the acoustic agitator and the continuous process vessel can operate at a mechanical resonance. Operating at a mechanical resonance allows for energy efficient operation of the acoustic agitator under highly kinetic conditions. The acoustic agitator agitates the continuous process vessel at a frequency greater than <NUM> and less than <NUM>.

In some implementations, the method <NUM> can include introducing a midstream reactant into the elongated tube via a second reactant inlet coupled to the elongated tube. The midstream reactants can be, for example and without limitation, reactants requiring less residence time within the process vessel, or reactants intended to react with a product of an initial reaction occurring in the upstream portion of the elongated tube.

The method <NUM> includes discharging, from a product outlet coupled to a second end of the elongated tube, a product of a chemical reaction from the continuous process vessel (stage <NUM>).

In some implementations, the method <NUM> can include introducing, via a coolant inlet, a cooling fluid into an interstitial region within the continuous process vessel and surrounding the elongated tube. The cooling fluid can circulate around and conduct heat away from an outer surface of the elongated tube. The method <NUM> can include discharging, via a coolant outlet, the cooling fluid from the interstitial region so as to remove heat from exothermic reactions occurring within the elongated tube.

In some implementations, the method <NUM> can include introducing, via a heater inlet, a heating fluid into an interstitial region within the continuous process vessel and surrounding the elongated tube, or duct. The heating fluid can circulate around and conduct heat into an outer surface of the elongated tube. The method <NUM> can include discharging, via a heater outlet, the heating fluid from the interstitial region. The heating fluid can add heat to initiate chemical reactions, or accommodate endothermic reactions occurring within the elongated tube.

<FIG> illustrate different views of an example horizontal plate process vessel <NUM> suitable for use as a continuous acoustic chemical microreactor, according to an illustrative implementation. The process vessel <NUM> includes a plate <NUM> defining an elongated tube, referred to with respect to this implementation as a reaction channel <NUM>. <FIG> illustrates a first horizontal cross section of the plate <NUM> showing the various channels defined therein including the reaction channel <NUM>. <FIG> illustrates a second horizontal cross section of the plate <NUM> showing various inputs and outputs defined therein. The first and second horizontal cross sections of <FIG>, respectively, are taken at different points along an axis perpendicular to the cross section; for example, the first cross section may be taken at a point above or below the second cross section along the axis. <FIG> illustrates a vertical cross section of the process vessel <NUM> showing the plate <NUM> and other components. As shown in <FIG>, the oscillation axis of the process vessel <NUM> lies in the vertical plane; that is, the oscillation axis is perpendicular to the horizontal planes of the cross sections illustrated in <FIG>. <FIG> illustrates a perspective view of the process vessel <NUM>.

<FIG> illustrates the first horizontal cross section of the plate <NUM> of the process vessel <NUM>, according to an illustrative implementation. The plate <NUM> defines several channels including the reaction channel <NUM>, which conveys reactants, reagents, transit gasses, reaction products, et cetera through the process vessel <NUM>, and channels 952a through 952f (collectively "channels <NUM>"), which can convey heating or cooling fluids through the plate <NUM> to add or remove heat from reactions occurring within the reaction channel <NUM>. In some implementations, the plate <NUM> can define more or fewer channels. The plate <NUM> additionally defines several orifices including inlet orifices 925a and 925b (collectively "inlet orifices"), an outlet orifice <NUM>, inlet orifices 945a through 945f (collectively "inlet orifices <NUM>"), outlet orifices 946a through 946f (collectively "outlet orifices <NUM>"), and inlet orifices 922a and 922b (collectively "inlet orifices <NUM>"). Each of the various orifices connects its respective channel to one of the various inlets or outlets defined in the plate <NUM> and described below with reference to <FIG>. The various orifices can therefore pass substances between the various channels and the various inlets and outlets.

The reaction channel <NUM> can receive reactants, reagents, transit gas, et cetera from the inlet orifices <NUM>. These substances can be acted upon by an inner surface of the reaction channel <NUM> as the process vessel <NUM> is agitated by an acoustic agitator, such as the acoustic agitator 11a previously described. The agitation can promote mixing or reaction of the substances within the reaction channel <NUM>. In addition to the agitation, which occurs substantially along the axis perpendicular to the cross section, the substances exhibit a bulk flow through the reaction channel <NUM> from the inlet orifices <NUM> to the outlet orifice <NUM>, which passes the substances to an outlet <NUM> shown in <FIG>. In some implementations, the plate <NUM> can define one or more inlet orifices <NUM> for receiving midstream reactants, similar to the process vessel 18x described above with reference to <FIG>.

The channels <NUM> can receive heating or cooling fluids via the inlet orifices <NUM>, and pass them out of the outlet orifices <NUM>. In some implementations, the inlet orifices and outlet orifices can be reversed; that is, the heating/cooling fluids can travel through the channels <NUM> in the same direction as the reactants in the reaction channel <NUM>. In some implementations, certain channels <NUM> can pass a heating fluid while other channels pass a cooling fluid. For example, the channels 952a and 952b may receive a heating fluid via the inlet orifices 945a and 945b, while the channels 952e and 952f receive a cooling fluid via the inlet orifices 945e and 945f, or vice-versa. The inlet orifices <NUM> connect to inlets <NUM> shown in <FIG>, and the outlet orifices <NUM> connect to outlets <NUM> also shown in <FIG>.

<FIG> illustrates the second horizontal cross section of the plate <NUM> of the process vessel <NUM>, according to an illustrative implementation. As shown in <FIG>, the plate <NUM> defines various inlets and outlets for receiving and passing different substances including reactants, reagents, transit gasses, products, and heating/cooling fluids. The various inlets and outlets connect to the various inlet orifices and outlet orifices shown in <FIG>. In particular, the inlet 920a connects to the reaction channel <NUM> via the inlet orifice 925a, and the inlet 920b connects to the reaction channel <NUM> via the inlet orifice 925b. Similarly, the inlets 921a and 921b connect to the reaction channel <NUM> via the inlet orifices 922a and 922b, respectively. The reaction channel <NUM> connects to the outlet <NUM> via the outlet orifice <NUM>. The inlet 942a for heating/cooling fluids connects to the channels 952a and 952b via the inlet orifices 945a and 945b, respectively, and the channels 952a and 952b connect to the outlet 943a via the outlet orifices 946a and 946b, respectively. The inlet 942b for heating/cooling fluids connects to the channels 952c and 952d via the inlet orifices 945c and 945d, respectively, and the channels 952c and 952d connect to the outlet 943b via the outlet orifices 946c and 946d, respectively. The inlet 942c for heating/cooling fluids connects to the channels 952e and 952f via the inlet orifices 945e and 945f, respectively, and the channels 952e and 952f connect to the outlet 943c via the outlet orifices 946a and 946b, respectively. In some implementations, the plate <NUM> can define more or fewer channels and corresponding inlets, outlets, and orifices. The inlets and outlets can be configured to receive and pass substances via hoses or pipes connected thereto. Accordingly, the inlets and outlets may include features for receiving and retaining the hoses or pipes such as threads, flanges, or edges.

<FIG> shows a vertical cross sections of an example horizontal plate process vessel <NUM> suitable for use as a continuous acoustic chemical microreactor, according to an illustrative implementation. The process vessel <NUM> can include an upper cap <NUM>, a seal <NUM>, a cap plate <NUM>, a seal <NUM>, the plate <NUM> previously described, a seal <NUM>, a base plate <NUM>, and a mounting flange <NUM>. The process vessel <NUM> assembly can be held together by bolts <NUM>, and mount to the acoustic agitator via the mounting plate <NUM>. In some implementations, the process vessel <NUM> can be removably mounted to the acoustic agitator using bolts, clips, clamps, clasps, or other fasteners. The cap plate <NUM> can define additional channels <NUM>, which can be used for conveying additional heating or cooling fluids in proximity to the reaction channel <NUM>. The heating or cooling fluid can be held within the cavity formed by the upper cap <NUM>. The cavity formed by the upper cap <NUM> can be similar to the interstitial regions 52w and 52x previously described. The cap plate <NUM> and plate <NUM> can be made of a thermally conductive material such as a metal or alloy to promote heat transfer between the reaction channel <NUM> and the channels <NUM> and <NUM>. The process vessel <NUM> can be configured to oscillate along the oscillation axis shown in <FIG>.

Claim 1:
A continuous acoustic chemical microreactor system comprising:
a continuous process vessel (18w) configured to oscillate along an oscillation axis, the continuous process vessel including:
a reactant inlet (20w) configured to receive one or more reactants into the continuous process vessel;
an elongated tube (70w) coupled at a first end to the reactant inlet and configured to receive the reactants from the reactant inlet, wherein the elongated tube has an inner surface having a hydraulic diameter of less than <NUM>; and
a product outlet (26w) coupled to a second end of the elongated tube and configured to discharge a product of a chemical reaction among the reactants from the continuous process vessel; and
an acoustic agitator (11a) coupled to the continuous process vessel and configured to agitate the continuous process vessel along the oscillation axis such that the inner surface of the elongated tube accelerates the one or more reactants in alternating upward and downward directions along the oscillation axis, wherein the acoustic agitator is configured to agitate the continuous process vessel at a frequency greater than <NUM> and less than <NUM>,
characterized in that:
the elongated tube (70w) is aligned relative to the oscillation axis such that the upper and lower portions of the inner surface of the elongated tube agitate the reactants.