Presentation on theme: "Understanding the Basics of Membrane Filtration CHEN 320 – Group 7"— Presentation transcript:
1 Understanding the Basics of Membrane Filtration CHEN 320 – Group 7 Lianne Monterroso Scott SheltonPatricia Stratton Emily Wilborn
2 Roadmap Introduction to Membrane Filtration Pressure-Driven Membrane SeparationMembrane Materials, Structure, and MorphologyMembrane Format and Module DesignMATLAB CodeCommon Membrane ApplicationsConclusion
3 Introduction to Membrane Filtration Accounts for 40% to 70% of capital and operating costs in the chemicals industryBroad range of applicationsProcess Water TreatmentWastewater treatment and reuseMetal and catalyst recoverySolvent recoveryGas separationConcentration of heat sensitive biological macromolecules and proteins
4 Two Main Types of Filtration Membrane filtration can be accomplished with either dead end filtration or crossflow filtration.Dead-end: Filter cake can form reducing filtration capacity.Crossflow: Maintains more steady permeate flux and low pressure.Figure: Created by Group 7Figure: Created by Group 7
6 Reverse Osmosis Employs tightest membranes for liquid separation. Only allows small water-soluble ions to go through membrane along with water.
7 NanofiltrationRemoves multivalent ions and small molecules in nanometer range like sulfate ions, and sugars.The most common type used for nanofiltration is the spiral membrane.
8 UltrafiltrationUsed to retain relatively large dissolved materials like proteins and starches.Ultrafiltration membranes are typically classified by their ability to retain component specific sizes.
9 MicrofiltrationSuspended solids and large colloids are rejected, while dissolved solids and macromolecules pass throughOperate at low pressures of 10 psi or less.
10 Membrane Materials Structure and Morphology FabricationDesired PropertiesClassifications
11 Fabrication of Membranes Membranes are fabricated from variety of materialsMade of Inorganic and organic materialsMetals, polymers, and ceramics are used for different applications based on their properties
12 Ceramics and Metals Ceramic and Metals used for aggressive media Suitable for high temperature operations, acids, and strong solvent
13 PolymersPolymers are utilized most because of their price and versatilityPolymer membranes are typically made up of a thin layer of polymer on a porous backing, creating a material with high permeability, selectivity, mechanical strength, and chemical stability
15 ClassificationMembranes are classified according to structure, morphology, and applicationTwo classifications of membranesSymmetric membranesAsymmetric membranesComposite membranes
16 Symmetric MembranesVery few commercially available membranes are symmetric throughout their thicknessSome examples include:PolytetrafluoroethylenePolyethylenePolypropylene
17 Asymmetric MembranesInclude most of the commercially available membranesHave either a thin microporous or dense permselective layer supported by a more-open porous substrateThe membrane may by integrally skinned, formed in a single operation, or by separate stepsAn example of an asymmetric membrane is cellulose RO membrane, where both layers are made up of cellulose acetate.
18 Composite MembranesA composite membrane is a subset of asymmetric membranesThe skin layer and support layer are made up of different polymers based on the individual propertiesThe skin layer determines separation performanceSupport layer determines mechanical stabilityAn example of a composite membrane is a polymide RO membrane which is made up of a thin polyamide permselective skin on a polysulfone UF support.
20 Cassette Cassette membranes are used for UF and MF. The membrane filtrates the fluid, while the gaskets are used to separate the permeate, feed, and retentate streams.Spacers introduce turbulence, which increases mixing and prevents the formation of a gel layer.However, spacers are sometimes prone to particulate clogging, and can be difficult to clean.Source: "Understand the Basics of Membrane Filtration." Wang, Hua. Hongyi, Zhou. GE Global Research.
22 Cartridge Utilizes laminar flow for MF, UF, or NF. Composed of a large number of hollow-fiber membranes in a cylindrical housing with permeate ports and end caps.Has a very high packing density, therefore has a high surface area to volume ratio, making this particular filter ideal for product recovery.Source:Source: "Understand the Basics of Membrane Filtration." Wang, Hua. Hongyi, Zhou. GE Global Research.
23 Spiral Wound Spiral Wound are used predominantly for RO. They are composed of a multi-layered assemble of flat sheet membranes, and spacer screens.These components are all rolled around a perforated tube, which seals the membrane and spacer layers on three sides.Source: "Understand the Basics of Membrane Filtration." Wang, Hua. Hongyi, Zhou. GE Global Research.
24 Spiral Wound Module used for RO They are built to have a high packing density by utilizing thin spacer screens.Industrially, large-scale operations use these RO modules connected in parallel with one another.Source:
25 Plot of Cake Resistance vs Plot of Cake Resistance vs. Specific Resistance with the Area of the Membrane and Cake Volume held constant>> % Rc: cake resistance>> % r: specific cake resistance>> % Vs: volume of cake>> % Am: area of membrane>>>> %Plot of Rc vs. r (Vs = m^3, Am = .01 m^2)>> r = linspace(0,10);>> Vs = 0.001;>> Am = .01;>> Rc = r*Vs/Am;>> plot(r,Rc,'-')>> legend('Vs and Am constant')>> title('Plot of Rc vs. r')>> xlabel('r (m^-2)')>> ylabel('Rc (m^-1)')Figure: Created by Group 7Source for Filtration equation:
26 Plot of Cake Resistance vs Plot of Cake Resistance vs. Cake Volume with the Area of the Membrane and specific resistance held constant>> % Rc: cake resistance>> % r: specific cake resistance>> % Vs: volume of cake>> % Am: area of membrane>>>> %Plot of Rc vs. Vs (r = 5 m^-2, Am = .01 m^2)>> r = 5;>> Am = .01;>> Vs = linspace(1e-6,1,400);>> Rc = r*Vs/Am;>> plot(Vs,Rc,'-')>> legend('r and Am constant')>> title('Plot of Rc vs. Vs')>> xlabel('Vs (m^-3)')>> ylabel('Rc (m^-1)')Figure: Created by Group 7Source for Filtration equation:
27 Plot of Cake Resistance vs Plot of Cake Resistance vs. Area of the Membrane with the specific resistance and Cake Volume held constant>> % Rc: cake resistance>> % r: specific cake resistance>> % Vs: volume of cake>> % Am: area of membrane>>>> %Plot of Rc vs. Am (r = 5 m^-2, Vs = .001 m^3)>> Am = linspace(.0001,1,400);>> r = 5;>> Vs = .001;>> Rc = r*Vs./Am;>> plot(Am,Rc)>> title('Plot of Rc vs Am')>> legend('r and Vs held constant')>> xlabel('Am (m^2)')>> ylabel('Rc (m^-1)')Figure: Created by Group 7Source for Filtration equation:
28 Common Membrane Applications Desalinization using ROIndustrial water treatmentBiopharmaceutical manufacturingClarification steps in cellulosic ethanol productionPicture:
29 Desalination for Reverse Osmosis Picture: "Understand the Basics of Membrane Filtration." Wang, Hua. Hongyi, Zhou. GE Global Research.Cost-effectiveProduce clean water from seawater in regions with limited access to fresh waterRemoves salts, organic substances, algae, bacteria, and suspended particles
30 Industrial Water Treatment High purity water needed for:Boiler feed waterCooling tower waterProcess water in many industriesPicture:
31 Membrane filtration technology minimizes land, construction, and operating costs: Conventional TreatmentMembrane TreatmentPicture: "Understand the Basics of Membrane Filtration." Wang, Hua. Hongyi, Zhou. GE Global Research.
37 ConclusionDifferent types of membranes can be applied to various applications based on particle size:Reverse Osmosis (Smallest constituent)NanofiltrationUltrafiltrationMicrofiltration (Largest constituent)Membrane filtration has lots of applications!Several types of driving forces for membrane filtration:Pressure DifferenceConcentration DifferenceTemperature DifferenceUsed in many industrial processes:DesalinationWastewater and process water treatmentBiopharmaceutical applications
38 Suggested Work For Improvements Add a chemical to the solution being filtered to make membrane more durableCombine multiple driving forcesIntroduce turbulent flow to prevent clotting