Patent Application
20090297410
The present invention relates to microreactor technology. Microreactors are commonly referred to as microstructured reactors, microchannel reactors, or microfluidic devices. Regardless of the particular nomenclature utilized, the microreactor is a device in which a sample can be confined and subject to processing. The sample can be moving or static, although it is typically a moving sample. In some cases, the processing involves the analysis of chemical reactions. In others, the processing is executed as part of a manufacturing process utilizing two distinct reactants. In still others, a moving or static target sample is confined in a microreactor as heat is exchanged between the sample and an associated heat exchange fluid. In any case, the dimensions of the confined spaces are on the order of about 1 mm. Microchannels are the most typical form of such confinement and the microreactor is usually a continuous flow reactor, as opposed to a batch reactor. The reduced internal dimensions of the microchannels provide considerable improvement in mass and heat transfer rates. In addition, microreactors offer many advantages over conventional scale reactors, including vast improvements in energy efficiency, reaction speed, reaction yield, safety, reliability, scalability, etc.
Microreactors are often used in chemical processes where the reactants comprise liquids and gases and the microreactor is designed to mix gas and liquid reactant phases to produce one or more specific product molecules. In order to perform a high yield or high selectivity gas/liquid reaction, it is often necessary to provide a relatively high interfacial surface area between the gas and liquid phases of the reaction. Although, the gas and liquid phases may exhibit a variety of degrees of miscibility, in many cases the reactants are immiscible under ordinary conditions. Accordingly, the present inventors have recognized the need for microreactor schemes that can improve yield and selectivity, even for relatively immiscible gas and liquid reactants, particularly for microreaction technology at production level.
According to one embodiment of the present invention, a microreactor assembly is provided comprising a fluidic microstructure and an injector assembly. The injector assembly comprises a liquid inlet, a gas inlet, a liquid outlet, a gas outlet, a liquid flow portion extending from the liquid inlet to the liquid outlet, and a gas flow portion extending from the gas inlet to the gas outlet. Further, the injector assembly defines a sealed injection interface with a microchannel input port of the fluidic microstructure. The injector assembly is configured such that the gas outlet of the gas flow portion is positioned to inject gas into the liquid flow portion upstream of the liquid outlet, into the liquid flow portion at the liquid outlet, or into an extension of the liquid flow portion downstream of the liquid outlet. Further, the injector assembly is configured such that gas is injected into the liquid flow portion or the extension thereof as a series of gas bubbles. The resulting microreactor assembly, and the injector assemblies utilized therein, which can be used with a variety of microreactor designs, effectively improves the interfacial surface area within the microstructure without requiring excessive reduction of microchannel dimensions.
The following detailed description of specific embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
Referring to
The liquid inlet 22 is configured to define a sealed, readily engageable and disengageable interface with a liquid reactant supply, which may comprise another fluidic microstructure or a liquid source. Similarly, the gas inlet 24 is configured to define a sealed, readily engageable and disengageable interface with a gas reactant supply. In either case, the readily engageable and disengageable interface may be provided in the form of any conventional or yet to be developed fluid fittings, utilizing any suitable sealing configuration including, but not limited to, O-rings, gaskets, etc. It is noted that the recitation of a liquid inlet or liquid outlet as such does not preclude operation of the injector assembly 20 where gas and liquid flow together through the liquid inlet or outlet, as would be the case in the embodiment of
The injector assembly 20 defines a sealed injection interface with the microchannel input port 14 of the fluidic microstructure 10. In the embodiment illustrated in
Although it is contemplated that the size distribution of the injected gas bubbles will be relatively wide, a majority of the bubbles injected into the liquid flow portion 30 will have a diameter of between approximately 100 μm and approximately 100 μm. In one embodiment of the present invention, where the diameter of the gas outlet 28 is restricted to approximately 60 cm, and the downstream fluidic microstructure 10 contributes a back pressure of about 1.5 bar across the gas outlet, the most prevalent bubble size will fall between approximately 250 μm and approximately 350 μm. As the back pressure approaches about 3.0 bar across the gas outlet, the most prevalent bubble size will tend to fall between approximately 200 μm and approximately 300 μm. It is contemplated that gas outlet diameters suitable for generation of bubbles of this size will typically, but not necessarily, be less than approximately 100 μm or, more preferably, between approximately 30 μm and approximately 80 μm.
Referring further to the embodiment illustrated in
To further encourage proper bubble injection and optimum size distribution, the injector assembly 20 can be configured such that the liquid flow portion 30 and the gas flow portion 40 define substantially co-axial flow paths in the relative vicinity of the point at which gas is injected into the liquid flow portion 30, i.e., in the vicinity of the gas outlet 28. Further, it is contemplated that the gas flow portion 40 can be positioned and configured to inject gas into the liquid flow portion 30 along a gas injection vector VG that is substantially parallel to the liquid injection vector VL defined by the liquid flow portion 30 at the liquid outlet 26. Although preferred injector assembly materials are Teflon, PFA, Titanium, Stainless steel, Hastelloy, and Sapphire, it is contemplated that injector assemblies according to the present invention may be constructed of glass, ceramics, glass/ceramic composites, or any other suitable conventional or yet-to-be developed materials.
The present inventors have recognized that in positioning and installing the injector assembly 20 and the associated fluid tubing to be coupled to the gas inlet 24, it would often be beneficial to have the ability to orient the gas inlet 24 of the injector assembly 20 in any of a variety of positions. Accordingly, injector assemblies according to the present invention can be configured to permit active orientation of the gas inlet 24, relative to a remainder of the injector assembly 20, without disruption of the sealed injection interface. For example, referring to
Referring to
If the fluidic microstructure 10 is configured to mix two reactants A, G, it will typically comprise fluidic microchannels that are configured to distribute the reactants across a plurality of reactant flow paths. Each of these reactant flow paths would then be subsequently directed to a mixing zone within the microstructure 10 where the reactants mix and react. The fluidic microstructure 10 may also comprise thermal fluid microchannels configured for thermal exchange between a reactant fluid in the fluidic microchannels and a thermal fluid in thermal fluid microchannels defined in the fluidic microstructure 10. Alternatively, the fluidic microstructure 10 may merely be configured as a single function microstructure, i.e., as a fluid distribution microstructure, a thermal exchange mictrostructure, a reactant mixing microstructure, or a multichannel quench-flow or hydrolysis microreactor. The specific design of the fluidic microstructure for any combination of these functions can be gleaned from a variety of teachings in the art, including those present in Corning Incorporated European Patent Applications EP 1 679 115 A1, EP 1 854 536 A1, EP 1 604 733 A1, EP 1 720 650 A0, and other similarly classified European patents and patent applications.
It is also contemplated that the liquid and gas inlets 22, 24 of the various embodiments of the present invention may be configured such that the liquid inlet 24 serves only to introduce a purge gas or liquid into the injector assembly 20 and the fluidic microstructure 10 to remove trapped air in the vicinity of the nozzle portion of the injector assembly 20. In this case, the injector assembly 20 would merely send gas into the fluidic microstructure 10 during operation and, in cases where dead volumes would not be acceptable from a process point of view, an injector design is contemplated where the liquid flow portion 30 would be removed. In such a case, the injector assembly 20 could resemble a single part needle of one piece design, with the rotary body portion 21 removed.
Referring to
It is noted that recitations herein of a component of the present invention being “configured” in a particular way, to embody a particular property, or function in a particular manner, are structural recitations as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “configured” denote an existing physical condition of the component and, as such, are to be taken as a definite recitation of the structural characteristics of the component.
For the purposes of describing and defining the present invention it is noted that the terms “approximately” and “substantially” are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation.
Having described the invention in detail and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08305039.3 | Feb 2008 | EP | regional |
This application claims priority to European Patent Application number EP 08305039.3 filed Feb. 29, 2008 titled, “Injector Assemblies and Microreactors Incorporating The Same”.
