2000 W Processor with Water-Cooled Transducer
SYSTEM DESCRIPTION
Industrial Sonomechanics (ISM)’ 2000 W (output power) ultrasonic liquid processor system is a "special request" unit, designed for flow-through or batch production on a commercial scale. The system operates at the frequency of approximately 18 kHz. FBH-type Barbell horns used in this system have output tip diameters of 60 mm, with larger diameters (up to 75 mm) available upon request. These horns can provide stable operation at output amplitudes up to 85 microns in aqueous loads at a normal pressure, corresponding to acoustic power intensities up to 55 W/cm2. The system is able to directly reproduce any laboratory or bench-scale process optimization study in a commercial production environment. Since the scale-up from lab/bench to commercial size can be accomplished without changing any of the optimized parameters, including the amplitude, the process is guaranteed to generate the same reproducible results on the plant floor as it did in the laboratory. The system is based on a water-cooled magnetostrictive transducer, which offers several advantages, as described below.
System Schematic
2000 W flow-through ultrasonic reactor system in its most common configuration is illustrated on the left. Ultrasonic generator, controlled form the front panel interface or (optional) from a computer running Generator Control software, excites vibrations in the magnetostrictive transducer, which are subsequently amplified by the Full-wave Barbell horn. The horn delivers the ultrasonic energy to the liquid, flowing through the reactor chamber. The reactor chamber may include a cooling/heating jacket. The working liquid inlet and outlet valves may be designed to enable adjustable, pressurized (if needed) flow through the ultrasonic reactor chamber (optional). The system can be designed to operate under static pressures of up to 3 atmospheres.
The processor can be configured for use in hazardous environments, such as chemical factories or refineries, by incorporating the following protective features into its magnetostrictive transducer and ultrasonic generator:
- The transducer can be built without any high-power cable connections. In this configuration, the Teflon-insulated wire wound around its magnetostrictive element continues uninterrupted from the unit all the way to the generator, thereby eliminating any possibility of creating a spark inside a failed connector. In addition, since the unit is water-cooled, any possibility of introducing a hazardous gas into its internal area is eliminated.
- Two methods of protection may be employed for the ultrasonic generator: a) since generator can be fully monitored and controlled by a computer, it may be kept out of the hazardous area altogether; b) the generator may be designed to be water-cooled, which means that it will not depend on the external air for heat removal. The generator’s enclosure can, therefore, be sealed and/or pressurized with an inert gas, eliminating the possibility of introducing external air (possibly with hazardous gasses) into its internal area.
Maximum flow rate through the processor is approximately 10,000 liters/hour (44 gpm). The system design corresponds to the International Patent Application PCT/US2008/068697, "High capacity ultrasonic reactor system". The incorporated Barbell horn design corresponds to the US Patent 7,156,201, "Ultrasonic rod waveguide-radiator".
Photographs of System Components
Photographs are presented of: 1 - magnetostrictive transducer assembled with Full-wave Barbell horn, 2 - magnetostrictive transducer assembled with Full-wave Barbell horn and reactor chamber without a cooling jacket, 3 - Full-wave Barbell horn, 4 – reactor chamber with cooling jacket, 5 – magnetostrictive transducer.
Besides Full-wave Barbell horns (FBH) of the type shown on the left, specialized Half-wave Barbell horns (HBH) and Half-wave Barbell horns with an Opening (HBHO) are available. These horns are shorter and lighter than Full-wave Barbell horns and have shapes that, when incorporated into appropriately designed reactor chambers, ensure that no working liquid bypasses the active cavitation zone.
Half-wave and Barbell horns with an Opening are frequently preferred for the tasks involving high-intensity flow-through ultrasonic processing, such as dispersion and deagglomeration of solid particles, nanoemulsification and the production micronized waxes, where uniform exposure to ultrasound and the resulting narrow particle size distributions are essential. Different types of Barbell horns are described in detail on another page.
Photograph of a Common System Setup
Photograph of a common system setup is presented, where: 1 – 5000 W ultrasonic generator, 2 - magnetostrictive transducer (maximum output power - 2000 W), 3 - Barbell horn and reactor chamber, 4 – liquid pump, 5 – liquid storage tank.
This arrangement is simple and commonly used for processes that require recirculation of the working liquid through the reactor. It is similar to setups in Schematics 1 and 3 illustrated below, but differs from Schematic 1 in that there is no tank for supplying additional components (assuming that the premixing of components is carried out elsewhere) and from Schematic 3 in that it allows the product after each pass to mix with the precursor liquid in the tank. This setup s appropriate for many processes, such as mixing, extraction, homogenization, sonochemstry, and the production of nano-emulsions and nano-dispersions with narrow particle size distributions.
Common Setup Schematic 1
A common setup of the 2000 W ultrasonic system is shown, where: 1 - 5000 W ultrasonic generator; 2 – computer running Generator Control software, 3 - magnetostrictive transducer (maximum output power - 2000 W); 4 - Full-wave Barbell horn; 5 – flow-through reactor chamber; 6 – pump; 7 - pipeline; 8 – tank for supplying additional components; 9 – valve; 10 – main liquid supply tank. This setup may be used for such processes as biodiesel production, nano-emulsification, oil extraction, solid particle dispersing, etc. The product may be collected from the product output line or re-circulated into the main liquid supply tank, 10.
Common Setup Schematic 2
Large batch (1 - 20 liters) processes may be carried out using the setup illustrated in this schematic. The flow-through reactor chamber is replaced by a batch container. The working liquid may be cooled by using a batch container equipped with a water cooling jacket. Ultrasonic generator, 1, excites vibrations in the magnetostrictive transducer, 2, which are subsequently amplified using the Full-wave Barbell horn, 3, and delivered to the working liquid in the batch container, 4. If desired, the ultrasonic generator may be programmed and the data may be recorded by a computer, 5, running Generator Control software. This setup may be used for such processes as biodiesel production, nano-emulsification, oil extraction, solid particle dispersing, etc.
CHALLENGING PROCESS SETUP SCHEMATICS
The following two schematics illustrate setup arrangements that can be used for especially challenging processes, such as the production of translucent nanoemulsions with dispersed phase droplet diameters below 100 nanometers. These processes frequently require longer ultrasound exposure times, which may be achieved by reducing liquid flow rates through the reactor, passing the liquid several times through the system (Schematic 3) or utilizing several in-series reactors (Schematic 4).
Common Setup Schematic 3
Schematic is illustrated of a setup appropriate for challenging processes, such as the production of translucent nanoemulsions in which the dispersed phase droplet sizes must be below 100 nanometers. Coarse pre-emulsion (premix) is initially supplied through the "premix supply" line into vessel, 6. Ultrasonic generator, 1, controlled by computer, 2, excites mechanical vibrations in magnetostrictive transducer, 3, which are amplified by Full-wave Barbell horn, 4. Pass 1: liquid is drawn from the bottom of vessel, 6, through valve, 7, by pump, 8, which then pushes it into reactor, 5, through valve, 9. From there it is deposited into vessel, 11, through valve, 10. Pass 2: liquid is drawn from the bottom of vessel, 11, through valve, 7, by pump, 8, which then pushes it into reactor, 5, through valve, 9. From there it is deposited into vessel, 6, through valve, 10. The process repeats itself for as many passes as needed, and when it is finished, the resulting product comes out through valve, 7, pump, 8, and valve, 9, out of "product exit" line. Nitrogen gas, 12, maintains inert atmosphere and provides the necessary static pressure.
Common Setup Schematic 4
Diagram of a translucent nanoemulsion production process is shown in this example, which utilizes a multiple series ultrasonic reactor setup. Oil and aqueous phases are brought together in appropriate proportions and are sequentially pumped through multiple ultrasonic reactors, each incorporating a magnetostrictive transducer and a Full-wave Barbell horn.