Solvent Cycle, Methods for Solute Precipitation Heat and Mass Transfer: High Pressure chemical Engineering I (WS) Chapter 7

Flow Scheme of a Solvent Cycle

Solvent Cycle Steps: separate the extract from the solvent (1), clean the solvent for reuse (2), remove the solvent from raffinate (3), adjust composition of solvent mixture (if applicable) (4). Solvent Cycle

Single stage Multiple stage Counter- Chromato- (precipitation) current graphic SFE Modes of Operation

Extraction From Solids S t S / F Essential oils(5 %) Edible oils(2 %) 40 < 1  40 Coffee decaffeination (0.01 %) 200  5  40 Black tea decaff. (0.01 %) 230  1.5  150 Total amount of solvent S, kg/kg F Extraction time t, h Solvent to Feed Ratio S/F, kg S /(kg F h) Basis: Solvent: Carbon dioxide MPa, 330 K Solvent Cycle: Solvent to feed ratio of SFE processes

Countercurrent Separation V/L v S / F FAEE, FAME (5 %)   125 FFA (fatty acids) (2 %)  50 Squalene (1.5 %)   50 Tocopherol-Purif. (2.5 %) 35  20  45 Solvent ratio V/L, kg/kg Reflux ratio v, - Solvent to feed ratio S/F, kg F /kg F Basis: Solvent: Carbon dioxide MPa, 350 K Solvent Cycle: Solvent to feed ratio of SFE processes

Chromatographic Separation P r t r S / F DHA / DPA  x 10 3 EM Phytol-isomers  900 EM  200 SMB Productivity Pr, g P /(kg StPh h) Retention time, min Solvent to feed ratio S/F, kg F /kg F Basis: Solvent: Carbon dioxide MPa, 310 K Solvent Cycle: Solvent to feed ratio of SFE processes

Reduction of pressure or density Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Birtigh, Brunner, Johannsen Solubility of Caffeine in CO 2

Gas Circuit in the Compressor Mode

Compressor Process, Throttling Sub-Critical

Compressor Process, Throttling Super- Critical

Pump Process

Pump Process, Throttling, Sub-Critical

Pump Process, Throttling Super- Critical

Extraction temperature: 313 K Energy Consumption by Various Solvent Cycles

Mechanical Energy Thermal energy in Thermal energy out Pump with heat recovery Pump without heat recovery Compressor with heat recovery Compressor without heat recovery Extraction pressure [MPa] Energy [kJ/kg] Energy needed for the gas cycle  70 kJ/kg CO2  95 kJ/kg CO2 for S/F 125 kg/kg: 8750 kJ/kg Feed kJ/kg Feed

Reduction of pressure or density (temperature) Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Brunner 1983 Solubility in a Gas With a Modifier (Entrainer) Influence of temperature

Data by: Gährs 1984 Ebeling, Franck 1984 Johannsen, Brunner 1994 Solubility of Caffeine in CO 2

Reduction of pressure or density Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Gährs 1984 Anti-Solvent: Solubility of Caffeine in CO 2 Influence of nitrogen

Reduction of pressure or density Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Solvent Cycle With Membrane Separation

GKSS-membrane (organic, active dense layer) CO 2 OC Permeate Retentate 1.86 wt.-% < 0.06 wt.-%  p = 2.0 MPa active dense layer 1.5 mole CO 2 kg/(m 2 h) P = 18 MPa, T = 323 K Separation by Membranes

Solvent Cycle in a T,s - Diagram Extraction/ separation Precipitationat high  p Precipitation at low  p Compressormode Entropy Temperature CO 2

53 kJ/ kg CO2 21 kJ/ kg CO2 7.6 kJ/ kg CO2 Like in 2 Energy For Different Solvent Cycles Pump-Cycle Compressor-Cycle Membrane-Cycle Sartorelli 2001

Reduction of pressure or density Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Adsorption of Caffeine on Activated Carbon

Silica with 52% loading, loaded by high pressure adsorption Silica with 50% loading, loaded by mixing, conventional process Recovery of Tocopherolacetate by Adsorption

Reduction of pressure or density Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Phase Equilibrium Caffeine - Water - CO 2

Reduction of pressure or density Anti solvent Membrane separation Adsorption Absorption De-Entrainment Modes For Product Recovery

Brunner 1983 Solubility in a Gas With a Modifier (Entrainer) Influence of temperature

Birtigh De-Entrainment

Generalization of Precipitation: Membership - Functions Temperature at the Swimming Pool T [ o C]  x  (x) (x) „Hot“ Not yet hot Too hot  (x): relative number of statements from people at the pool

Birtigh Membership Functions  P Adsorption Membrane

Absorption De-Entrain  T   T  Birtigh Membership Functions