Design And Experimental Study Of A Pressure Swing Separation System For Continuous Subcritical CO₂ Extraction Of Pranuts

Peanuts are rich in oil,protein,and polysaccharide resources,and are one of the widely cultivated oil and cash crops in the world.With the increasingly diversified processing methods of peanuts and the improvement of residents’living standards,the total proportion of peanuts used for oil extraction has decreased year by year,while the proportion of peanuts used for rough processing and deep processing has increased year by year.The processing methods of peanuts and peanut oil urgently need to be updated and iterated,Based on this,the author proposed a pressure swing separation system such as continuous subcritical CO₂extraction,which realized the continuous extraction and separation of oils and fats,reduced the energy consumption of traditional processes,and reduced the environmental pollution caused by the extraction fluid and raffinate.He also conducted process and experimental research on pressure swing separation systems such as continuous subcritical CO₂extraction of peanuts.Through the process design of five subsystems:continuous extraction subsystem,isobaric ion separation system,constant pressure circulation subsystem,depressurized ion separation system,and pressurized circulation subsystem,a pressure swing separation process flow scheme for peanut continuous subcritical CO₂ extraction with six extractors and two separation kettles was finally determined.Through uniform design experiments,the optimal parameters of the CO₂subcritical extraction isobaric supercritical separation process were preliminarily obtained:extraction pressure 20 MPa,separation temperature 65℃,pump frequency 27.5 Hz,extraction time180 min,and the peanut extraction rate was 35.02%.Through a single factor experiment,the optimal parameters for continuous subcritical CO₂extraction and other pressure swing separation processes for peanuts were obtained as follows:extraction pressure 20MPa,separation temperature 60℃,pump frequency 15Hz,extraction time 400min,and the final extraction rate of peanut oil was 45.13%.The design and calculation of the extractor were carried out using a cylindrical and toothed clamp structure.The stress intensity of each part of the toothed clamp was checked through calculation,and the stress analysis was conducted using ANSYS software to analyze the stress situation of the extractor structure.Adding a spiral fin structure to the inside of the tubular heat exchanger to enhance the heat transfer ability,and using Fluent software to conduct fluid simulation calculations on the spiral fin tubular heat exchanger,finally selecting a 100mm pitch spiral fin as the optimization scheme for the future intermediate heat exchanger.