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NCHU-ChE: Ch. 1-1 超臨界流體分離技術 Special Topics on Separation Using Supercritical Fluids 化學工程學系 與 環境工程學系 碩博士班 選修課程 國立中興大學 化材館.

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Presentation on theme: "NCHU-ChE: Ch. 1-1 超臨界流體分離技術 Special Topics on Separation Using Supercritical Fluids 化學工程學系 與 環境工程學系 碩博士班 選修課程 國立中興大學 化材館."— Presentation transcript:

1 NCHU-ChE: Ch. 1-1 超臨界流體分離技術 Special Topics on Separation Using Supercritical Fluids 化學工程學系 與 環境工程學系 碩博士班 選修課程 國立中興大學 化材館

2 NCHU-ChE: Ch. 1-2 Content of Lectures

3 NCHU-ChE: Ch. 1-3 Overview on Separation Processes with scFluids Solubility in Supercritical Fluids/ Phase Equilibria Extraction from Solid Substrates (I, II) Countercurrent Multistage Extraction (I, II) Topics I

4 NCHU-ChE: Ch. 1-4 Solvent Cycle, Heat/ Mass Transfer, Precipitation Supercritical Fluid Chromatography, SFC Membrane Separation Enzymatic Reactions in scFluids for Separation Crystallization in Supercritical Fluids General Aspects of Separation Processes Videos Visited to Supercritical Fluid Plants Topics II

5 NCHU-ChE: Ch. 1-5 Raw Materials Separation Clean Air Contaminants Effluent Air Reaction Recovery Separation Purification Separation RecycleSide Products Products Effluent Water Contaminants Clean Water Generalized Process Scheme

6 NCHU-ChE: Ch. 1-6 Focus on Chemistry and Reactor Technology Separation Technology was Added Afterwards for Recovery and Purification of Products from Reaction Mixtures Minimisation of Waste Discharged into the Environment Chemical Engineering Education Focussed on Large Scale Petrochemical Separations Separation Technology in the Past

7 NCHU-ChE: Ch. 1-7 Consequences: Chemistry and Reactor Technology Capabilities Limits Maximum Yields Minimal Time for Separation Technology Development Most New Processes use Existing Separation Technology Drive for Product Purity and Environmental Impact Minimi- zation Results in Increased Production Separation Technology in the Past

8 NCHU-ChE: Ch. 1-8 Best Known Most Used Strengths: Limited Equipment Simple Staging Economy of Scale Energy Costs Reliable Design and Scale Up Distillation Conventional Process

9 NCHU-ChE: Ch. 1-9 Low Relative Volatilities Azeotropes Close Boiling Points Isomers Feed Composition Low Concentrations with High Boiling Point Overlapping Boiling Points Non-Volatile Components Extreme Conditions (Pressure, Temperature) Small Capacities Product Degradation Fouling Uneconomical for Environmental Applications Limits to Distillation

10 NCHU-ChE: Ch Drivers for New Separation Concepts Sustainable Processes Higher Molecular Efficiencies New Feedstock Chemistry Reduction Energy Consumption Environmentally Benign Mass Separatiing Agents Minimal Consumption Separating Agents Cleaner and Purer Products Contamination with Mass Separating Agents Removal of Undesired Components Purer Feedstocks Minimisation Environmental Impact Further Emission Reduction Minimal Waste Stream Production

11 NCHU-ChE: Ch Some Challenges Clean Processes Environmentally Benign Solvents Solid Solvents No Solvents Reduced Energy Consumption Increases Solvent / Adsorbent Capacities Selectivity Enhancement Reduction Evaporative Operations Process Intensification In Situ Separations Hybrid Separations

12 NCHU-ChE: Ch Benign Solvents Replacement of Chlorinated, Aromatic and Other Harmful Solvents in Reactions and Separations by: Water Aqueous Solvents Two Aqueous Phases Carbon Dioxide (Supercritical or Liquid) Food Applications Neutraceuticals, Pharmaceuticals ? Mixtures of Unsuspected Solvents (Reactive Solvents) Insoluble Alkane / Complexing Agent Mixtures Solid Solvents (Adsorbents) No Solvents However:Low Volatile Solvents in Reactions may Create Problems in Separation and Purification

13 NCHU-ChE: Ch Special Use Liquid Membranes Knowledge Affinity Separationes Field-induced Separations Chromatography Supercritical Extraction Membranes: gas feed Adsorption: liquid feed Membranes: liquid feed Adsorption: gas feed Ion Exchange Solvent Extraction Crystallization Absorption Distillation Extractive & Azeotropic Distillation Separation Processes General

14 NCHU-ChE: Ch Summary & Conclusions Strong Drive to For New Separation Concepts Chemical instead of Physical Separation Solvent Free Separations Rate Based Separations Environmental and Product Acceptable Mass Separating Agents Hybrid Separation Systems Integration of Reaction and Separation This Requires the Application of New Often Highly Selective Separation Systems Application of New Separation Systems often Prohibited by Lack of Knowledge on Design and Scale-Up

15 NCHU-ChE: Ch Supercritical Fluid Supercritical Fluid Extraction - SFE (Gas Extraction) Definition “Supercritical”

16 NCHU-ChE: Ch Supercritical Fluid Extraction - SFE (Gas Extraction) State of Solvent Stripping Adsorption L-L extraction Absorption High pressure liquid extraction

17 NCHU-ChE: Ch Generalized Process Scheme

18 NCHU-ChE: Ch Solvents EC directive 84/344/EEC Extraction solvents which are acceptable for all uses when used in compliance with GMP provided any residues or derivatives present in the product in technically unavoidable quantities present no danger to human health. PropaneEthanol Butane Carbon Dioxide ButylacetateAcetone EthylacetateNitrous Oxide Mixtures Nitrogen, Water

19 NCHU-ChE: Ch Comparison of States GasSupercritical Liquid Fluid ______________________________________________ 0.1 MPa P c,T c 4P c,T c 0.1 MPa 298 K 288 K ______________________________________________  kg/m  kg/(ms) D m 2 /s _____________________________________________________________________

20 NCHU-ChE: Ch typical operating conditions Density of Carbon Dioxide Calculated with Bender-EOS

21 NCHU-ChE: Ch New, better products Clean products New, better processes „Supercritical Fluids“, Why?

22 NCHU-ChE: Ch Advantages of Supercritical Fluids Lower operating temperatures improved yield improved product properties favourable combination of process steps easier regeneration of the sc solvent no liquid solvent lower production cost

23 NCHU-ChE: Ch Advantages of Supercritical Fluids ctd. Solvent power comparable to liquid solvents Solvent power adjustable by pressure and temperature changes Very hígh volatility compared to the dissolved substances complete separation of solvent from extract and raffinate second phase achievable in all cases high diffusivity, low viscosity CO 2 : nontoxic, nonflammable, inexpensive, available

24 NCHU-ChE: Ch Disadvantages of Supercritical Fluids Elevated pressures required Relative high costs of investment (not in general !) Unusual operating conditions (for some industries) Complicated phase behaviour (but only some knowledge needed for application)

25 NCHU-ChE: Ch CaffeineTheobromine Example: Decaffeination

26 NCHU-ChE: Ch Decaffeination of green coffee beans Lack and Seidlitz 1993

27 NCHU-ChE: Ch Decaffeination of green coffee beans Lack and Seidlitz 1993

28 NCHU-ChE: Ch Flow scheme of decaffeination plant Schoeller-Bleckmann design Lack and Seidlitz 1993

29 NCHU-ChE: Ch Dissolution: Separation Processes Reactions Combinations (e.g. Separation by Reaction) Engineering of Properties (liquid) Dilution Lowering of viscosity Lowering of concentration Application of Supercritical Fluids

30 NCHU-ChE: Ch Product Engineering (Materials) Small particles Particles with large surface area Adsorbates Coated particles Engineering of Properties (solid) Penetration Swelling Removal of monomers Impregnation of substances (Dyes, pharmaceuticals) Application of Supercritical Fluids

31 NCHU-ChE: Ch Application of Supercritical Fluids Engineering of phase transitions Formation of solid phases (Micronization, thin layers) Variation of solubility (g-l) Variation of melting point (l-s)

32 NCHU-ChE: Ch Product Applications I Extraction, purification, and separation of: Edible oils and fats Hops extract Natural dyes: Annatto, Hibiscus Vitamins (Tocopherols, Vit. E, Tocotrienols) Carotenoids Sterols Essential fatty acids (EPA, DHA, DPA) Application of Supercritical Fluids

33 NCHU-ChE: Ch Product Applications II Bioactive compounds, e.g. Pyrethrum Caffeine, Theobromine Cholesterol Spices: Capsaicin, Pepper, Coriander Mono- and Diglycerides Aroma compounds Thiosulfinates Citrus oils Antioxidants: Vitamin E, Ascorbic acid, Polyphenoles, Diacin, Genicin (Steroids) Application of Supercritical Fluids

34 NCHU-ChE: Ch Separation Processes: Extraction from solids Countercurrent multistage separation Chromatographic separations Precipitation Crystallization Absorption Adsorption/Desorption and with the application of: Chemical reactions Solid and liquid surfaces.... Application of Supercritical Fluids

35 NCHU-ChE: Ch Chemical Reactions New Syntheses Variation of reaction equilibrium Variation of reaction rate Replacing liquid solvents Application of Supercritical Fluids Examples: Hydrolysis: From starch to sugars Enzymes as catalyst in CO 2 -atmosphere

36 NCHU-ChE: Ch Environmental Engineering Replacement and Recycling of Solvents Recovery of Hazardous Waste Compounds Destruction of Hazardous Waste Compounds Application of Supercritical Fluids

37 NCHU-ChE: Ch Biotechnology Enzymatic Catalysis Engineered degradation of Biopolymers (Starch) Production of Proteins Separation of Products from aqueous solutions Sterilization/Deactivation Enantiomeric selective reactions Application of Supercritical Fluids


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