For the past six years, Accudyne Systems has produced commercial laboratory scale supercritical fluid (SF) processing machines for Supercritical Fluid Technologies (SFT). These machines include the SFT Phase Monitor, SFT-150, SFT-250, and SFT-1000. The latter three machines represent increasing controls sophistication, with the SFT-150 having very basic temperature controls and the SFT-1000 having automated pressure sequencing and programmable cosolvent dosing. The control systems for all these systems were developed by ASI. The process flow scheme for each was developed in collaboration with SFT.

The work between ASI and SFT has resulted in the award of two U.S. Patents for precision high pressure control of SF units. These patents refer to the pressure control scheme enabling pressure regulation of a SF system to better than 0.1 bar in 700 bar under steady state conditions. Developed in collaboration with SFT using ASI prior art in the use of electropneumatic regulators and closed loop control systems, the control scheme leverages the mechanical capabilities of air-driven piston pumps. This control scheme enables the SFT-250 and SFT-1000 to maintain tight pressure regulation in the presence of large variations in CO2 flow rates.

In collaboration with SFT, ASI has designed and deployed pilot scale SF systems that have leveraged the patented pressure control scheme and the control system capabilities of the SFT-1000 system. An early pilot plant version was designed and built for Delphi Automotive Systems and is currently being used in an extraction cleaning process related to lithium polymer battery production.

A more recent SF pilot plant system was designed and constructed for a major pharmaceutical company.This system employed the pressure, temperature, and dosing controls of the SFT-1000 system in the context of a 20 L main extraction vessel that was ASME code rated to 10,000 psi (690 bar) maximum allowable working pressure (MAWP). Per customer specifications, the CO2 preheater heat exchanger was designed to operate at up to 250 degrees C under continuous flow conditions. The main vessel was designed and tested to operate at up to 150 degrees C. Leveraging duplex air driven pumps, the system achieves CO2 flow rates of 1.2 L/min at 6500 psi (450 bar). System performance has been experimentally validated during customer buyoff trials and subsequent investigation.