超臨界流體分離技術 special topics on separation using supercritical fluids...
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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. Content of Lectures. Topics I. Overview on Separation Processes with scFluids Solubility in Supercritical Fluids/ Phase Equilibria Extraction from Solid Substrates (I, II) - PowerPoint PPT PresentationTRANSCRIPT
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
NCHU-ChE: Ch. 1-2
Content of Lectures
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
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
NCHU-ChE: Ch. 1-5
RawMaterials
Separation
Clean Air
Contaminants
Effluent Air
Reaction Recovery
Separation
Purification
Separation
Separation
Recycle Side Products
Products
Effluent Water
Contaminants
Clean Water
Generalized Process Scheme
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
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
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
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
NCHU-ChE: Ch. 1-10
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
NCHU-ChE: Ch. 1-11
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
NCHU-ChE: Ch. 1-12
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
NCHU-ChE: Ch. 1-13
SpecialUse
Liquid Membranes KnowledgeAffinity 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
NCHU-ChE: Ch. 1-14
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 Prohibitedby Lack of Knowledge on Design and Scale-Up
NCHU-ChE: Ch. 1-15
Supercritical Fluid
Supercritical Fluid Extraction -
SFE
(Gas Extraction)
Definition “Supercritical”
NCHU-ChE: Ch. 1-16
Supercritical Fluid Extraction -
SFE
(Gas Extraction)
State of Solvent
Stripping
Adsorption
L-L extraction
Absorption
High pressure liquid extraction
NCHU-ChE: Ch. 1-17
Generalized Process Scheme
NCHU-ChE: Ch. 1-18
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.
Propane Ethanol
Butane Carbon Dioxide
Butylacetate Acetone
Ethylacetate Nitrous Oxide
MixturesNitrogen, Water
NCHU-ChE: Ch. 1-19
Comparison of States
Gas Supercritical Liquid Fluid
______________________________________________ 0.1 MPa Pc,Tc 4Pc,Tc 0.1 MPa
298 K 288 K______________________________________________
kg/m3 1 200 - 500 400 - 900 1000
kg/(ms) 10- 5 1.3.10-5 3.9.10-5 10- 3
D m2/s 10- 5 0.7.10-7 0.2.10-7 10-9
_____________________________________________________________________
NCHU-ChE: Ch. 1-20
--- typical operating conditions
Density of Carbon Dioxide
Calculated with Bender-EOS
NCHU-ChE: Ch. 1-21
New, better products
Clean products
New, better processes
„Supercritical Fluids“, Why?
NCHU-ChE: Ch. 1-22
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
NCHU-ChE: Ch. 1-23
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
•CO2: nontoxic, nonflammable, inexpensive, available
NCHU-ChE: Ch. 1-24
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)
NCHU-ChE: Ch. 1-25
CaffeineTheobromine
Example: Decaffeination
NCHU-ChE: Ch. 1-26
Decaffeination of green coffee beans
Lack and Seidlitz 1993
NCHU-ChE: Ch. 1-27
Decaffeination of green coffee beans
Lack and Seidlitz 1993
NCHU-ChE: Ch. 1-28
Flow scheme of decaffeination plant
Schoeller-Bleckmann design
Lack and Seidlitz 1993
NCHU-ChE: Ch. 1-29
Dissolution:Separation Processes
ReactionsCombinations
(e.g. Separation by Reaction)
Engineering of Properties (liquid) Dilution
Lowering of viscosityLowering of concentration
Application of Supercritical Fluids
NCHU-ChE: Ch. 1-30
Product Engineering (Materials)
Small particlesParticles with large surface areaAdsorbatesCoated particles
Engineering of Properties (solid)
PenetrationSwellingRemoval of monomersImpregnation of substances(Dyes, pharmaceuticals)
Application of Supercritical Fluids
NCHU-ChE: Ch. 1-31
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)
NCHU-ChE: Ch. 1-32
Product Applications I
Extraction, purification, and separation of:
Edible oils and fatsHops extract
Natural dyes: Annatto, HibiscusVitamins (Tocopherols, Vit. E, Tocotrienols)
Carotenoids Sterols
Essential fatty acids (EPA, DHA, DPA)......
........
Application of Supercritical Fluids
NCHU-ChE: Ch. 1-33
Product Applications II
Bioactive compounds, e.g. PyrethrumCaffeine, Theobromine
Cholesterol
Spices: Capsaicin, Pepper, Coriander
Mono- and DiglyceridesAroma compounds
ThiosulfinatesCitrus oils
Antioxidants: Vitamin E, Ascorbic acid, Polyphenoles, Diacin, Genicin (Steroids)
......
Application of Supercritical Fluids
NCHU-ChE: Ch. 1-34
Separation Processes:
Extraction from solidsCountercurrent multistage separationChromatographic separationsPrecipitationCrystallizationAbsorptionAdsorption/Desorption
and with the application of:
Chemical reactionsSolid and liquid surfaces....
Application of Supercritical Fluids
NCHU-ChE: Ch. 1-35
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 CO2-atmosphere
NCHU-ChE: Ch. 1-36
Environmental Engineering
Replacement and Recycling of Solvents
Recovery of Hazardous Waste Compounds
Destruction of Hazardous Waste Compounds
Application of Supercritical Fluids
NCHU-ChE: Ch. 1-37
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