Liquid-liquid extraction (LLE) is a method of separating or purifying dissolved materials by taking advantage of their respective solubilities in immiscible liquids. LLE may be used in separating biomolecules, lipid and fatty acids, impurities from water and beverages, metal complexes from mixed aqueous streams, radioisotopes, etc. Appearance of phase entrainment (also referred to as phase carryover) may be an indication of LLE system failure, e.g., microfluidic device failure, millifluidic device failure, etc., when a liquid phase exits the wrong outlet port, e.g., unwanted liquid appears at the outlet port of the opposite phase. Phase entrainment is the result of flow conditions of the system and the physical properties of the liquids involved, and is an indicator of flow stability. The volume fraction of such phase entrainment can provide valuable information regarding the degree of failure and the ability to recover phase separation once phase entrainment has occurred.
Although phase entrainment may be seen in certain circumstances in transparent tubing with the naked eye, it is not only difficult to quantify it in real time but it is also impractical to monitor over long periods of time by collecting large volumes of outlet fluids and measuring phase ratios ex-situ. Moreover, since many liquids appear to be similar to one another by the naked eye, it can be difficult to identify whether phase entrainment is present. Even if phase entrainment is successfully identified, it is difficult to quantify solute concentration by the naked eye in a fluid stream.
In recent years, the use of sensors have become prevalent in monitoring flow for process automation and optimization. For example, sensors for hot wire anemometry, shear force measurement, charge pulse injection and ionic species detection, pressure differential sensing, detection of Coriolis forces, and observance of fluorescence and photobleaching, etc., have been successfully used for continuous liquids. Unfortunately, the efficacy of the sensors for continuous liquids is hampered when more than one phase is present because of variability in viscosity, density, transport coefficients, and the appearance of interfacial and capillary forces.
It is appreciated that the flow may be controlled for droplet monodispersity to perform analysis on materials encapsulated in droplets using sensors, e.g., 2D bright-field and fluorescence microscopy, laser spectroscopy, NMR, electrophoresis, image cross correlation, shadowgraphy, etc. Biphasic microfluidics have been used with capillary number and Reynolds number that are typically small with interface formation that is accurately controlled and is related to dynamic viscosity, phase velocity, density, the system's characteristic length, and interfacial tension. Unfortunately, the sensors used in analyzing the solute concentration within droplets are not only expensive but they also require extensive analysis that renders them impractical for industrial use.
Accordingly, a need has arisen to quantify phase entrainment, identify bulk phase (pure liquid) presence, and measure solute concentration that is practical for industrial use. According to some embodiments, an optical detector, e.g., a linear CMOS sensor, may be used along with a light source, e.g., LED light source, to illuminate a solution in a transparent container in order to leverage shadowgraphy to quantify phase entrainment, identify bulk phase presence (i.e., determine the purity of the liquid), and/or measure solute concentrations by measuring the light intensity and comparing it to developed models to identify the refractive index that is indicative of respective concentrations. It is appreciated that various techniques including average pixel ratio and/or menisci counting analysis have been used to quantify phase entrainment, identify bulk phase presence, and/or measure solute concentration. The average pixel ratio may be used to identify bulk liquids and their constituents.
In some embodiments, a liquid may be passed through a segment of transparent container (e.g., cylindrical tubing with circular cross section, tubing with rectangular cross section, etc.). Slugs (also referred to as droplets) are formed if two liquids or a liquid and a solute are present as they travel through the container. A light source, e.g., light emitting diode (LED), white light source, laser, etc., illuminates the transparent container that the liquid is traveling through while a detector, e.g., a line sensor such has 1×2048 CMOS pixels, a linear charged coupled detector (CCD) array, etc., captures a “shadow” cast by the droplets (i.e., leading and trailing edge of the droplets). The leading and trailing edge of the droplets cast shadows on the detector, which appear as intensity features (peaks). The number of peaks can be used to quantify carryover (i.e., phase entrainment). The average pixel ratio based on the measured light intensity (that changes due to different refractive indices associated with each liquid and/or slug) can be used to identify bulk phase presence.
It is appreciated that different solute concentrations can result in different refractive indices. These different indices, in addition to the dimensions of the system, e.g., dimensions of the transparent tubing, etc., can lead to variations in light intensity. As such, in embodiments, models (e.g., empirically developed, software generated, etc.) may be developed for a given system setup (i.e., based on specific dimensions) to illustrate correspondence between different liquid concentrations to refractive indices and light intensity. Thus, the system may be leveraged to measure the light intensity and the measured light intensity may be compared to the generated model, or in some embodiments to a comparison sample in real time, to identify the correspondence refractive index and as such concentrations associated with each liquid.
These and other features and aspects of the concepts described herein may be better understood with reference to the following drawings, description, and appended claims.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Before various embodiments are described in greater detail, it should be understood that the embodiments are not limiting, as elements in such embodiments may vary. It should likewise be understood that a particular embodiment described and/or illustrated herein has elements which may be readily separated from the particular embodiment and optionally combined with any of several other embodiments or substituted for elements in any of several other embodiments described herein. It should also be understood that the terminology used herein is for the purpose of describing the certain concepts, and the terminology is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood in the art to which the embodiments pertain.
As described above, a need has arisen to quantify phase entrainment, identify bulk phase (pure liquid) presence, and measure solute concentration that is practical for industrial use. The proposed system leverages less costly detectors (or sensors) to measure volume ratios of microfluidic liquid-liquid streams. The proposed system utilizes the tendency of phase entrainment to appear as slug flow (also referred to as droplets) in a narrow transparent container, e.g., transparent tubing. In some embodiments, the system includes an optical detector, e.g., a linear CMOS sensor, that is used with a light source, e.g., LED light source, to illuminate a solution in a transparent container. It is appreciated that in some nonlimiting examples, the light source may be strobed to illuminate the droplets and measure accurate positions of the droplets in a microfluidic chip, thereby reducing image blurring. The droplets may cast a shadow on the detector when the light source illuminates the transparent tubing. In some embodiments, the light intensity associated with positions of the droplets is different from light intensity where the droplets are absent, as measured by the detector. The variation in light intensities as measured by the detector may form peaks that corresponds to locations of the droplets. The number of droplets (e.g., as measured by the number of peaks also referred to as menisci counting analysis) may be used to quantify phase entrainment. It is appreciated that since the size of the droplets (e.g., dimensions such as length, width, etc.) may vary, another metric may be used for phase entrainment. For example, a ratio of light intensities between where the droplets are present and where the droplets are not present (also referred to as pixel ratio), along the length of the transparent container may be used as an indication of bulk phase presence (i.e., purity of the liquid). It is appreciated that since different liquids have different refractive indices, then the light intensities as measured by the detector varies where the droplets are formed in comparison to where the droplets are absent and can be used as a phase entrainment metric for bulk phase presence.
According to some embodiments, a concentration of different components in a liquid, such as different liquids, in the liquid-liquid extraction system may be determined. For example, a model may be generated (e.g., using software that takes into account the dimensions of the transparent container, the type of liquids in the mixture, etc., to associate light intensities to refractive indices to different concentrations of the types of liquid that are present in the mixture). It is appreciated that in some embodiments, the model may be empirically generated. Once the model is generated, a plurality of light intensities may be measured, as described above. In some embodiments, a statistical averaging may be performed to result in an average light intensity value. The measured average light intensity value may be compared by a processor to the generated model to find a match. Once the light intensity as measured is matched to the light intensity of the generated model, the refractive index and concentrations of the liquids may be determined. In other embodiments, instead of a model, there can be a comparative sample (with known refractive index and concentration) that can be used to make a real time comparison with currently measured values.
Accordingly, various metrics associated with the characteristics of a multi-component liquid such as phase entrainment or solute concentrations may be measured and identified by the proposed system that is less costly than the conventional methods while being more effective and accurate.
Referring now to
In some nonlimiting examples, the light source 110 may be an LED (providing 11.4 mW optical power for example), white light source, laser, etc., that illuminates the transparent container 120 that the liquid is traveling through. In some nonlimiting examples, the light source 110 may generate coherent light. In some embodiments, the light source 110 may be controlled to change the wavelength of the light based on the liquid mixture travelling through the transparent container 120. In some embodiments, the light source 110 may be positioned at 90° angle (i.e., perpendicular) to the transparent container 120 and the detector 130. It is appreciated that the embodiments are described with respect to the emitted light being perpendicular to the transparent container 120 and the detector 130 for illustrative purposes and should not be construed as limiting the scope of the embodiments. For example, in some applications the light source 110 may be positioned at an angle, e.g., 45° angle, 65° angle, etc., with respect to the transparent container 120 and the detector 130 to accentuate the shadow 132 (e.g., enlarge the shadow) being cast on the detector 130.
In some embodiments, the transparent container 120 may be cylindrical in shape or rectangular. However, it is appreciated that the embodiments are described with respect to the transparent container 120 being cylindrical for illustrative purposes and should not be construed as limiting the scope of the embodiments. The transparent container 120 may be made of Teflon fluorinated ethylene propylene (PEF) tubing with an outer diameter of 1.588 mm and an inner diameter of 0.750 mm and 200 mm in length for illustrative purposes. As described above, the dimensions of the transparent container 120 results in the phase entrainment to appear as droplets 122 (slug flow) when the liquid stream flows through the transparent container 120. It is appreciated that the transparent container 120 may act as a lens that changes the focal position as light source 110 illuminate the transparent container 120 and the liquid and/or droplets 122 passing through it. In some nonlimiting examples, the transparent container 120 may bend the light passing through it towards the higher refractive index as the liquid and/or droplets 122 are passing through it. In some nonlimiting examples, the transparent container 120 may attach to an output outlet of a device. As such, in an industrial setting a small portion of the liquid flowing may be diverted as a sample to determine the number of droplets, light intensity to determine concentration of liquid/droplets, etc. The droplets 122 may vary in shape and size as illustrated. In some embodiments, the liquid stream may include two different types of liquid or it may include liquid and solute (e.g., water and sucrose). It is appreciated that any discussion with respect to two types of liquid is for illustrative purposes only and should not be construed as limiting the scope of the embodiments. For example, the proposed system can be extended in liquid extraction that includes more than two liquid types. According to some embodiments, the aqueous phase and an organic phase of the liquid stream may flow into the transparent container 120 via a T-junction (not shown).
It is appreciated that the flow rate may be adjusted depending on the type of liquid(s), dynamic viscosity, interfacial tensions, liquid densities, capillary number, Reynolds number, etc. For example, in some embodiments, involving water and an organic (e.g., toluene) the largest flow rate for water or toluene may be 1000 ul/min given 8.9×10−4 Pa. s dynamic viscosity of water, 0.025 N/m interfacial tension between water and toluene, 0.750 mm diameter, water density of 1.0 g/ml, capillary number of 8.80×10−3 and Reynolds number of 16 to ensure droplet 122 formation in a squeezing and non-turbulent form.
The light source 110 illuminates the transparent container 120 as the liquid flows through the transparent container 120 forming droplets 122. The droplets change the light intensity (or cast a shadow 132) on the detectors 130 due to a different refractive index in comparison to the rest of the liquid mixture. The detector 130 may be an optical detector and in one nonlimiting example is positioned 100 mm from the light source 110. In some embodiments, the detector 130 may be a line sensor such as 1×2048 CMOS pixels (each pixel may be 14×200 microns) with the array length of 28.672 mm which given the 0.75 mm tubing inter diameter provides a 12.7 uL interrogation volume, a linear charged coupled detector (CCD) array, etc., that captures the shadow 132 cast by the droplets 122 (i.e., leading and trailing edge of the droplets). It is appreciated that in some nonlimiting examples, the diameter of the transparent container 120, e.g., a tube, may be small enough, thereby enabling the droplets flowing through to be detected, e.g., inner diameter of a tube being 1 mm enables a droplet with larger radius to be detected. The shadow 132 changes the light intensity that is being measured by the detector 130. In other words, shadows may appear as intensity features (peaks), as shown in
It is appreciated that since the droplets 122 may vary in shape and size, the number of droplets 122 may not be an accurate reflection of phase entrainment. As such, the processor 140 may further perform other types of processing to determine metrics associated with phase entrainment. As discussed above, light intensities as measured by the detector are different in presence of droplets 122 in comparison to absence of droplets 122 regardless of whether a shadow is cast on the detector 130 because the refractive index associated with each is different (e.g., refractive index associated with a first liquid is different from a second liquid). Accordingly, an average pixel ratio based on the measured light intensities associated with each pixel of the linear CMOS detector 130 may be used to determine the bulk phase presence (purity of the liquid). The average pixel ratio may be provided by equation (1) as shown below:
<R>=1/NΣn=1N(InS/InB) (1)
In the equation above R is the average ratio, N is the total number of pixels in the detector 130, n is pixel index, and IS and IB are light intensities for signal (e.g., droplet) and background (e.g., bulk) respectively. For illustrative purposes,
In some nonlimiting examples the processor 140 may further perform other types of processing to determine metrics associated with phase entrainment similar to the pixel ratio that was described above. In some nonlimiting examples, the length of the droplets may also be used as another metric for phase entrainment analysis to determine volumetric ratios. The volumetric ratio may be provided by equation (2) below:
Where NDroplet let is the number of droplets within the transparent container 120, 1 is the average length of the droplet, and 2048 are number of pixels for the detector 130. For illustrative purposes,
It is therefore appreciated that the length of the droplets may be measured, the average light intensity across the CMOS detector 130 may be measured, the number of peaks may be measured, etc. As such, use of the one or more of the factors above by the processor 140 may determine the amount of liquid versus slug or droplets. It is appreciated that the embodiments are not limited thereto and that the embodiments should not be construed as limited to liquid and droplets. For example, a similar approach may be used for one type of liquid (with a solute in the liquid) versus another type of liquid due to difference in their refractive index resulting in a change in light intensity.
In some nonlimiting examples, various species in liquid flowing may be partitioned by monitoring liquid flowing through the transparent container 120 and by processing the droplets/light refractive index. One application may be in petroleum industry to partition various species in liquid flowing through the transparent container. It is appreciated that in some nonlimiting examples, a different detector 130 may be used. For example, in some embodiments instead of using a linear CMOS detector, a liquid detector may be used, which is a photo interrupter and u-shaped that is placed on one side of a receiver. In yet another example, a refractive or scattering detector (configured to sense refractive index or scattered light) that may be used to detect species within the liquid and/or droplets within the liquid. In some embodiments, various factors may be used to identify a suitable detector to use. For example, the fluorescence, remission, and/or absorption associated with the liquid flowing through the transparent container may be considered to determine an appropriate detector to use.
It is appreciated that the images may be successively captured at a framerate of 1 Hz for illustrative purposes. However, a different framerate may be used and the particular framerate of 1 Hz is for illustrative purposes and should not be construed as limiting the scope of the embodiments.
Referring now to
The system 200B of
The system 200C of
The system 200D of
It is appreciated that the position of the polarizer and/or diffuser is for illustrative purposes. For example, the polarizer and/or diffuser may be positioned anywhere on the optical path. Moreover, it is appreciated that use of polarizer and/or diffuser is for illustrative purposes and that other components, e.g., a filter, etc., may be used. Moreover, it is appreciated that a bandpass filter may be in conjunction with the system setup above for
Referring now to
In this nonlimiting example, the generated model for water and sucrose solution is provided and compared to toluene. As illustrated the light intensity decreases as the amount of sucrose increases in water due to an increase in its refractive index. It is appreciated that the model once generated can be used to determine the concentration of liquid(s) and/or solute. For illustrative purposes, the setup of
It is appreciated that variation in the described embodiments above may provide additional information. For example, spectroscopy may be used where the light source is approximately 780 nm in wavelength. In some nonlimiting examples, the light source may include a color metric species that may excite a particular wavelength and/or light (i.e. color) when illuminating the liquid and/or droplets within the transparent container. As such, variation in color and/or wavelength may also provide additional information regarding the liquid and/or droplets within the liquid. In some embodiments, the variation in color and/or wavelength may provide additional information regarding species present within the liquid flowing through the transparent container. In some embodiments, quantum dots may be used that are nanometer in size with optical and/or electrical properties where when illuminated by ultraviolet (UV) light, an electron in the quantum dot can be excited to a state of higher energy, thereby providing different kind of information regarding the liquid and/or droplets and/or species within the liquid.
In some examples, computer system 1100 can be used to implement computer programs, applications, methods, processes, or other software to perform the above-described techniques and to realize the structures described herein. Computer system 1100 includes a bus 1102 or other communication mechanism for communicating information, which interconnects subsystems and devices, such as a processor 1104, a system memory (“memory”) 1106, a storage device 1108 (e.g., ROM), a disk drive 1110 (e.g., magnetic or optical), a communication interface 1112 (e.g., modem or Ethernet card), a display 1114 (e.g., CRT or LCD), an input device 1116 (e.g., keyboard), and a pointer cursor control 1118 (e.g., mouse or trackball). In one embodiment, pointer cursor control 1118 invokes one or more commands that, at least in part, modify the rules stored, for example in memory 1106, to define the electronic message preview process.
According to some examples, computer system 1100 performs specific operations in which processor 1104 executes one or more sequences of one or more instructions stored in system memory 1106. Such instructions can be read into system memory 1106 from another computer readable medium, such as static storage device 1108 or disk drive 1110. In some examples, hard-wired circuitry can be used in place of or in combination with software instructions for implementation. In the example shown, system memory 1106 includes modules of executable instructions for implementing an operating system (“OS”) 1132, an application 1136 (e.g., a host, server, web services-based, distributed (i.e., enterprise) application programming interface (“API”), program, procedure or others). Further, application 1136 includes a module of executable instructions associated with model module 1141 to generate one or more models based on the system setup data 1140 (as described above). Once the model is generated, the model module 1141 may receive the measured light intensity 1142 and compare that to the previously generated model (or in some embodiments a real time measurement being made on a comparative sample) to determine the refractive index and the concentration associated with the measured light intensity. As such, the concentration, e.g., sucrose in water as described above, may be determined using the measured light intensity and by leveraging a previously generated model.
The term “computer readable medium” refers, at least in one embodiment, to any medium that participates in providing instructions to processor 1104 for execution. Such a medium can take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as disk drive 1110. Volatile media includes dynamic memory, such as system memory 1106. Transmission media includes coaxial cables, copper wire, and fiber optics, including wires that comprise bus 1102. Transmission media can also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.
Common forms of computer readable media include, for example, floppy disk, flexible disk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chip or cartridge, electromagnetic waveforms, or any other medium from which a computer can read.
In some examples, execution of the sequences of instructions can be performed by a single computer system 1100. According to some examples, two or more computer systems 1100 coupled by communication link 1120 (e.g., LAN, PSTN, or wireless network) can perform the sequence of instructions in coordination with one another. Computer system 1100 can transmit and receive messages, data, and instructions, including program code (i.e., application code) through communication link 1120 and communication interface 1112. Received program code can be executed by processor 1104 as it is received, and/or stored in disk drive 1110, or other non-volatile storage for later execution. In one embodiment, system 1100 is implemented as a hand-held device. But in other embodiments, system 1100 can be implemented as a personal computer (i.e., a desktop computer) or any other computing device. In at least one embodiment, any of the above-described delivery systems can be implemented as a single system 1100 or can implemented in a distributed architecture including multiple systems 1100.
In other examples, the systems, as described above can be implemented from a personal computer, a computing device, a mobile device, a mobile telephone, a facsimile device, a personal digital assistant (“PDA”) or other electronic device.
In at least some of the embodiments, the structures and/or functions of any of the above-described interfaces and panels can be implemented in software, hardware, firmware, circuitry, or a combination thereof. Note that the structures and constituent elements shown throughout, as well as their functionality, can be aggregated with one or more other structures or elements.
Alternatively, the elements and their functionality can be subdivided into constituent sub-elements, if any. As software, the above-described techniques can be implemented using various types of programming or formatting languages, frameworks, syntax, applications, protocols, objects, or techniques, including C, Objective C, C++, C#, Flex.™., Fireworks.®, Java™, Javascript™, AJAX, COBOL, Fortran, ADA, XML, HTML, DHTML, XHTML, HTTP, XMPP, Python, and others. These can be varied and are not limited to the examples or descriptions provided.
The foregoing description of various embodiments of the claimed subject matter has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art. Embodiments were chosen and described in order to best describe the principles of the invention and its practical application, thereby enabling others skilled in the relevant art to understand the claimed subject matter, the various embodiments and the various modifications that are suited to the particular use contemplated.
The instant application claims the benefit of and priority to the U.S. Provisional Application No. 63/273,366 filed on Oct. 29, 2021, which is incorporated herein by reference in its entirety.
This invention was made with government support under Contract No. 89233218CNA00000 awarded by the U.S. Department of Energy. The government has certain rights in the invention.
Number | Date | Country | |
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63273366 | Oct 2021 | US |