SFT Custom Solutions 

20 Liter Extractor for Polymer Cleaning

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SFE/SFR Pilot Systems

Supercritical Fluid Technologies Inc. has designed and constructed pilot scale supercritical fluid extraction and reaction systems. These larger systems incorporate and build upon many of the features found in SFT’s high end bench top systems. 

One of our first pilot scale SFE systems was designed and built to extract impurities in lithium batteries. This system is shown in the picture to the right. 

A more recent SF pilot plant system was designed and constructed for a major pharmaceutical firm. A simple flow diagram for this system is shown in the figure below. This system coupled the precise pressure, temperature, and dosing control features of SFT’s high end bench top equipment with a rack mounted, 20 liter extraction vessel that was ASME code rated to 10,000 psi (690 bar) maximum allowable working pressure (MAWP). 

Per project requirements, the CO₂ preheater heat exchanger was designed, to operate up to 250^oC under continuous flow conditions. The main vessel was designed and tested to operate up to 150^oC. With dual pumps, the system achieves CO₂ flow rates of 1.2 L/min at 6500 psi (450 bar). System performance was experimentally validated during customer trials and the subsequent development work performed on the equipment. The photos below show different views of the system, including the main operator interface and the computerized process monitoring system. 

20 Liter Supercritical Fluid Reaction System Enlarged view	Supercritical Fluid Reaction System Control Panel  Enlarged view
20 Liter Reaction System Process Lines and Magnadrive Impeller Mixer Enlarged view

The unique physical and chemical properties of carbon dioxide in its supercritical state, namely the extremely low surface tension, low viscosity, high diffusivity, and “tunable” solvent strength provide utility in a variety of industrial and scientific applications.

A client came to Supercritical Fluid Technologies looking for a new way to do resistive striping and surface deposition of photolithographic polymers. 

In the microelectronics fabrication industry, non-toxic, environmentally friendly SF CO₂ is being heavily investigated as an alternative agent for device cleaning, drying, and lithographic processing. With the advances in fabrication techniques and materials, microelectronic device features with dimensions below 100 nm are now possible to produce. At the sub-micron scale, the strong surface tension of the aqueous solvents currently used often causes pattern collapse during and after wet processing. The introduction of supercritical carbon dioxide to supplant more toxic aqueous solvents, especially in the lithographic steps, eliminates such adverse effects. 

For this application, Supercritical Fluid Technologies offered a special vessel configuration incorporating a unique lifting mechanism which provided the capability to rotate the complete vessel 180 degrees to allow the client access to the interior of the vessel and allow easy installation of components. This unit included a custom dense gas management package to deliver the various resistive stripping solvents in a controlled manner, and an integrated mass flow meter and weigh scale to complete mass balance calculations.

Processing System, Resistive Striping, Cleaning and Coating

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Supercritical Water Extraction/Reaction Systems

Supercritical Water Oxidation (SCWO) is among the most challenging applications of supercritical technology. Very high temperature (over 400^oC) and moderately high pressure are required to achieve the critical point of water. An additional difficulty is corrosion, a problem for all SCWO systems. Special materials for vessel linings and tubing are necessary to resist the highly reactive chemical species generated present during the oxidation process. 

These challenges demand superior design expertise for all systems components. The water and process stream must both be pumped to high initial pressures under exact flow and pressure control. The heat exchangers are subjected to high heat transfer rates at high temperatures, but must maintain precise temperature control. The reaction vessel requires precise temperature, pressure and flow control. The vessel must seal reliably and be leak free each time it is used, regardless of the harsh operating environment. Down stream processing such as cooling heat exchangers, collection vessels, gas/liquid separation and pressure control must be efficient.

Process control for the entire Supercritical Water Oxidation System may be as simple as manual valves and local process parameter display and control, or it may entail complete remote operation with computer process control and data acquisition. 

Leveraging technologies developed for processing of materials using supercritical carbon dioxide, Supercritical Fluid Technologies, Inc. has designed, manufactured, and deployed platforms for use with supercritical water.