MultiPhaseCavitator – Insert MPC48 for Ultrasonic Flow Cell
The MultiPhaseCavitator Insert (Insert MPC48) is designed to improve the ultrasonic processing of liquid/liquid or liquid/gas mixes. 48 very fine cannulas inject liquid or gas into a liquid phase right in the cavitation zone. This creates very small suspended droplets or gas bubbles yielding a very high specific surface area.
This insert is particularly useful for emulsion chemistry, such as Phase-Transfer-Reactions, Phase-Transfer-Catalysis (PTC) or Liquid-Liquid-Extraction. Another interesting field of application is the precipitation of particles from two liquid precursors or sono-crystallization. This insert is designed for Hielscher flow cell reactors and allows for batch or continuous processing.
One and 48 Injection Ports
Ultrasonication is an effective means for emulsification and mixing. Different from the conventional setup, where separate phases are combined before they enter the flow cell and the cavitation, this flow cell insert improves the combination of the two phases. When a liquid is injected through the 48 fine cannulas, it enters the flow cell in very narrow strands. The insert uses very 48 fine medical cannulas with inner diameters from 0.3mm to 1.2mm. These cannulas can be easily replaced and are a low cost consumable (sterile, approx. 2ct/pc). The ultrasonic cavitation (at 20kHz) cuts the 48 incoming liquid strands into small droplets when they enter the liquid phase in the flow cell.
The design applies the same feed pressure from one supply to all 48 cannulas to level the flow between the cannulas.
48 entry ports into ultrasonic reactor for liquid-liquid reactions
Injection into ultrasonic multiphasecavitator
InsertMPC48 – 48 fine cannulas end in the cavitation zone
Ultrasonic Flow Cell Reactor FC100L1K-1S with InsertMPC48
Uses and Applications
Hielscher ultrasonic reactors are often used to emulsify, to improve phase-transfer process kinetics or dissolving rates in liquid-liquid phase systems. Examples for such processes are the oxidative desulfurization with hydrogen peroxide and subsequent solvent extraction or the base-catalyzed transesterification of triglycerides.
Limited solubility of one reagent phase in another reagent phase is a significant problem in the process emulsion chemistry as both phases react with each other only at the interphase. Without ultrasonics, this results in low reaction rates and a slow conversion kinetics in two-phase systems.
Using the insert with an ultrasonic reactor, the cavitation produces high hydraulic shear and breaks the injected phase into sub-micron and nanosize droplets. As the specific surface area of the phase boundary is influential for the chemical rate of reaction this significant reduction in droplet diameter improves the reaction kinetics and may reduce or eliminate the need for phase-transfer agents. The volume percentage of the injected phase may be lowered, because finer emulsions need less volume to provide the same contact surface with the other reagent phase.
The use of this insert may lower the required amount of amphiphilic emulsion catalysts or phase-transfer catalysts (PTC), such as quaternary ammonium salts with their unique capability to dissolve in both aqueous and organic liquids.
Enhanced Mass-Transfer for Chemical Reactions
When two reagent phases react at a phase boundary, the reaction products accumulate at the droplet surface and block the reagent phases from interacting at the interface. The hydraulic shear caused by the ultrasonic cavitation results in turbulent flow and material transport from and to droplet surfaces and leads to the repeated coalescence and subsequent formation of new droplets. As the reaction progresses over time, sonication maximizes the exposure and interaction of the reagents.
This effect is used in many processes, such as the transesterification of vegetable oils to biodiesel or the synthesis of polyesters by the transesterification of diesters with diols to form macromolecules.
Emulsifying / Emulsification
This flow cell insert improves the emulsification when mixing immiscible liquids. This leads to smaller droplet sizes and a narrower size distribution – key factor for the stability of an emulsion. With this design you can inject and emulsify low and medium viscosity liquids into even high viscosity liquids, such as heavy fuel oils (HFOs), polymers or gels. Some formulations may require emulsifiers or stabilizers to be added. In this case it helps to mix the emulsifier uniformly. Customized designs for the injection of more than one phase though the cannulas are available on request.
Liquid-Liquid Extraction
This insert boosts liquid-liquid extraction processes by making a fine-size turbulent emulsion, e.g. of a solvent phase in a oil phase. Again, this increases the phase contact surface and results in better extraction and reduced solvent usage.
Aqua-Fuels for Cleaner Combustion
Low grade fuel oils, such as heavy fuel oil used on marine vessels or for power generation can be emulsified with water. This results in a more efficient combustion and in a significant reduction of NOx emissions and soot.
Read more about ultrasonic emulsification of aqua-fuels (emulsion-fuels)!
Precipitation / Sono-Crystallization
Pigments or nano-particles can be generated bottom-up by precipitation in liquids. In this case, a supersaturated mixture starts forming solid particles or crystals out of the highly concentrated material. These particles will grow to a certain point and finally precipitate. In order to control the particle/crystal size and morphology, controlling the precursor/reagent mixing is essential.
In general, the precipitation process involves: Mixing, supersaturation, nucleation, particle growth, and agglomeration. The latter is avoided by a low solid concentration or by stabilizing agents. The mixing is critical; as for most precipitation processes the speed of the reaction is very high. The InsertMPC48 combines fast narrow injected jets with strong ultrasonic cavitational shear. This maximizes the mixing speed and performance creating more and smaller particles.
Particle size distribution of Fe3O4 (magnetite) particles generated in an continuous ultrasonic precipitation reaction (Banert et al., 2004).
From Lab Testing to Pilot Scale and Production
Hielscher Ultrasonics offers equipment to test, verify and utilize this technology at any scale. The concept is easy to incorporate into existing processes.
- Feed phase A into liquid entry port at the bottom of the flow cell
- Feed phase B into smaller liquid entry port(s) at the side of the flow cell. This feed will be injected into the cavitational area through 48 fine pipes
- Adjust reactor pressure using a back-pressure valve at the flow-cell outlet port
At bench-top level the 1kW sonicator UIP1000hdT can process flow rates from 100 to 1000L/hr (25 to 250 gal/hr) for process demonstration and for the optimization of the sonication parameters. Hielscher ultrasonic processors are designed for linear scale-up to larger processing volumes at pilot or production scale. The table below lists processing volumes and recommended equipment sizes.
| Batch Volume | Flow Rate | Recommended Devices |
|---|---|---|
| 0.2L | 0.25 to 2m3/hr | UIP1000hdT, UIP2000hdT |
| 0.2L | 1 to 8m3/hr | UIP4000hdT |
| n.a. | 4 to 30m3/hr | UIP16000hdT |
| n.a. | above 30m3/hr | cluster of UIP10000 or UIP16000hdT |
Frequently Asked Questions about the MultiPhaseCavitator – Ultrasonic Flow Cell Insert MPC48
What is the MultiPhaseCavitator Insert (Flow Cell Insert MPC48)?
The MultiPhaseCavitator Insert (InsertMPC48) is a flow cell insert designed to improve ultrasonic processing of liquid/liquid or liquid/gas mixes. It uses 48 very fine cannulas that inject liquid or gas into a liquid phase right in the cavitation zone, creating very small suspended droplets or gas bubbles with a high specific surface area.
What does MPC48 mean?
MPC is the abbreviation for MultiPhaseCavitator. The number 48 indicates that the insert has 48 cannulas as injection sites. Upon request, the flow cell insert can be equipped with more or less cannulas.
How does the Flow Cell Insert MPC48 work?
When a liquid is injected through the 48 fine medical cannulas (inner diameters from 0.3 mm to 1.2 mm), it enters the flow cell in very narrow strands. Ultrasonic cavitation at 20 kHz cuts these incoming strands into small droplets as they enter the liquid phase. The design applies the same feed pressure from one supply to all 48 cannulas to level the flow between them.
What applications is the MultiPhaseCavitator Insert best suited for?
It is particularly useful for emulsion chemistry such as Phase-Transfer-Reactions, Phase-Transfer-Catalysis (PTC), and Liquid-Liquid-Extraction. It is also well suited to the precipitation of particles from two liquid precursors and to sono-crystallization. The insert is designed for Hielscher flow cell reactors and allows for batch or continuous processing.
How does the MPC48 insert improve phase-transfer reactions?
Because limited solubility of one reagent phase in another restricts reaction to the interphase, two-phase systems often have low reaction rates without ultrasonics. With the insert, cavitation produces high hydraulic shear and breaks the injected phase into sub-micron and nano-size droplets. This significant reduction in droplet diameter improves reaction kinetics and may reduce or eliminate the need for phase-transfer agents.
Can the insert reduce the amount of catalyst needed?
Yes. The insert can lower the required amount of amphiphilic emulsion catalysts or phase-transfer catalysts (PTC), such as quaternary ammonium salts, because finer emulsions need less volume to provide the same contact surface with the other reagent phase.
How does it enhance mass transfer in chemical reactions?
Reaction products can accumulate at the droplet surface and block reagent interaction at the interface. The hydraulic shear from ultrasonic cavitation creates turbulent flow and material transport to and from droplet surfaces, leading to repeated coalescence and formation of new droplets. Over time, sonication maximizes the exposure and interaction of the reagents – used in processes such as the transesterification of vegetable oils to biodiesel or the synthesis of polyesters.
Is the insert effective for liquid-liquid extraction?
Yes. The insert boosts liquid-liquid extraction by creating a fine-size turbulent emulsion, for example of a solvent phase in an oil phase. This increases the phase contact surface and results in better extraction with reduced solvent usage.
Can it be used for aqua-fuels?
Yes. Low grade fuel oils, such as heavy fuel oil used on marine vessels or for power generation, can be emulsified with water. This leads to more efficient combustion and a significant reduction of NOx emissions and soot.
Discover the benefits of ultrasonic emulsification of aqua-fuels!
How does the insert help with precipitation and sono-crystallization?
Pigments or nano-particles can be generated bottom-up by precipitation in liquids. The Insert MPC48 combines fast narrow injected jets with strong ultrasonic cavitational shear, which maximizes mixing speed and performance, creating more and smaller particles. Since the speed of many precipitation reactions is very high, controlling precursor/reagent mixing is essential, and the insert helps control particle/crystal size and morphology.
Are the cannulas consumables?
Yes. The 48 fine medical cannulas can be easily replaced and are a low-cost consumable (sterile, approx. 2 ct/pc). These cannulas are standard consumables and can be easily sourced locally. Customized designs for injecting more than one phase through the cannulas are available on request.
How do you set up the flow cell with the InsertMPC48?
The concept is easy to incorporate into existing processes: feed phase A into the liquid entry port at the bottom of the flow cell, feed phase B into the smaller liquid entry port(s) at the side (injected into the cavitational area through the 48 fine pipes), and adjust reactor pressure using a back-pressure valve at the flow-cell outlet port.
What scale-up options and equipment sizes are available?
Hielscher offers equipment to test, verify, and utilize this technology at any scale, with linear scale-up from bench-top to pilot and production. For example, a UIP1000hd (1 kW) can process 100–1,000 L/hr for demonstration and parameter optimization; recommended devices range from the UIP1000hd/UIP2000hd to the UIP4000 and UIP16000, with clusters of UIP10000 or UIP16000 for flow rates above 30 m³/hr.
Ultrasonic flow cell insert MPC48 – MultiPhaseCavitator