A schematic diagram of the pilot plant, Bench Scale SFE-500 Separex unit, is given in Figure 1.
Solvent (CO2), from the cylinder, is delivered through a pipe to the condenser. Liquid CO2 reaches the inlet of the high pressure pump rated up to 200 bar. Compressed fluid is fed to the heater prior to entering the extraction vessel. The unit contains an extraction container of 450 ml, closed with stainless steel porous discs. The extractor is heated by a heating jacket surrounding the outer surface of the vessel. The extraction pressure was controlled by means of a back pressure regulator valve, BPR (Tescom 27-1700) where depressurization of CO2 flow stream exiting the extraction vessel took place. The extracted substances were precipitated and collected into a glass trap, immersed in an ice bath. To ensure a total recovery of compounds, the gas flow coming out from the first trap passes through a second glass trap.The extraction pressure is measured at the entrance of the extraction vessel with an accuracy of ±1 bar (Wika, model 881.14.600).