Reverse Osmosis Reverse Osmosis Background to Market and to Market - PowerPoint PPT Presentation

Reverse Osmosis Reverse Osmosis Background to Market and to Market and Background Technology Technology 1

Technology and Applications Technology and Applications  Reverse osmosis has been commercial for Reverse osmosis has been commercial for  over 25 years. over 25 years.  60MLD plants built in Saudi Arabia 20 years 60MLD plants built in Saudi Arabia 20 years  ago. ago.  Current sales of RO membranes world Current sales of RO membranes world- -wide wide  are around $250 million per annum are around $250 million per annum excluding Japan. excluding Japan.  RO System sales could be as high as $1.0b RO System sales could be as high as $1.0b  per annum per annum 2

Membrane Market Membrane Market  Growth sector of the water treatment industry driven Growth sector of the water treatment industry driven  by reduced energy consumption and increased by reduced energy consumption and increased awareness of environmental impact/cost of ion awareness of environmental impact/cost of ion exchange operation exchange operation  Growth at 15 Growth at 15- -18% per annum 18% per annum   Main manufacturers are from USA Main manufacturers are from USA  - Dow/ Dow/Hydranautics Hydranautics/Fluid Systems /Fluid Systems USA USA - - Koch/ Koch/Dupont/Osmonics/Trisep Dupont/Osmonics/Trisep Japan Japan - - Nitto Denko/Toray/Toyobo Nitto Denko/Toray/Toyobo - 3

Fundamentals Fundamentals of Membranes and of Membranes and Reverse Osmosis Reverse Osmosis 4

Membrane Separation Membrane Separation 1 2 3 5 8 10 100 1000 10 4 10 5 10 6 10 7 Angstrom Pollens Sugars Beach Sand Viruses Bacteria Aqueous Salts Colloids Particle Filtration Microfiltration Ultrafiltration Nano- Filtration Reverse Osmosis 5

Pressure Driven Membrane Pressure Driven Membrane Processes - - Pressures Pressures Processes Membrane Typical Operating Membrane Typical Operating Process Pressure Range (PSI) Process Pressure Range (PSI) Reverse Osmosis Reverse Osmosis seawater 800 - - 1200 1200 seawater 800 brackish water 100 - - 600 600 brackish water 100 Nanofiltration 50 - - 225 225 Nanofiltration 50 Ultrafiltration 30 - - 100 100 Ultrafiltration 30 Microfiltration 2- - 45 45 Microfiltration 2 6

Impurities in Water Impurities in Water  Ionic Ionic   Non Ionic Non Ionic   Particulate Particulate   Microbiological Microbiological   Gases Gases  7

RO Removes RO Removes  Ionic Ionic   Non ionic Non ionic   Particulate Particulate   Microbiological Microbiological  8

When to Consider RO When to Consider RO  Water with TDS greater than 150 mg/L Water with TDS greater than 150 mg/L   Regenerant Regenerant cost reduction cost reduction   Waste cost reduction Waste cost reduction   Water conservation or recovery Water conservation or recovery  9

Pressure Filtration Pressure Filtration Not feasible for reverse osmosis A  rises to equal  B sparingly soluble solutes precipitate and foul the membrane 10

Cross Flow Filtration Cross Flow Filtration Required for reverse osmosis and nanofiltration A sweeps away membrane foulants B minimizes concentration polarization (maintains  –  difference) C generates a concentrate stream and a permeate stream 11

Cross- -Section of Thin Section of Thin- -film film Cross Composite Membranes Composite Membranes Polyamide Polyamide 0.2 µ µm m 0.2 Polysulfone Polysulfone Ultrathin Ultrathin Barrier Layer Barrier Layer 40 µ µm m 40 Microporous Microporous Polysulfone Polysulfone 120 µ µm m 120 Reinforcing Reinforcing Fabric Fabric 7 //

Thin- -film Composite film Composite Thin Membrane Chemistries Membrane Chemistries  Typical composition Typical composition   Fully aromatic polyamide (Dow FT30) Fully aromatic polyamide (Dow FT30)   Polypiperazineamide Polypiperazineamide (Dow NF45) (Dow NF45)   Polyvinyl alcohol ( Polyvinyl alcohol (Hydranautics Hydranautics) )   Sulfonated Sulfonated polysulphone polysulphone ( (Ionpure Ionpure) )  13

Schematic Cross Section Schematic Cross Section Permeate Channel Barrier Layer HOLLOW FINE FIBRE PERMEATORS 14

Spiral Wound Reverse Spiral Wound Reverse Osmosis Osmosis Brine Channel Spacer Product Water Flow Water Membranes Permeate Channel Spacer Brine Seal Brine Product Feed Water Brine 15

Reverse Osmosis Reverse Osmosis Water Flow Product Feed Concentrate Ions 16

Nanofiltration Definition Definition Nanofiltration  Minimum size rejected on order of one Minimum size rejected on order of one  nanometer nanometer  Between RO and UF Between RO and UF   Operates at ultra Operates at ultra- -low pressure low pressure   Selective permeation of ionic salts and Selective permeation of ionic salts and  small solutes small solutes 17

Nanofiltration Nanofiltration Water Flow Product Feed Concentrate Macromolecules Polyvalent Ions Monovalent Ions 18

Osmotic Processes Osmotic Processes Concentrated Pure Solution Water 19

Osmotic Processes Osmotic Processes Pure Concentrated Water Solution Osmosis 20

Osmotic Processes Osmotic Processes Pressure Concentrated Pure Solution Water Reverse Osmosis 21

Reverse Osmosis Involves Reverse Osmosis Involves  Application of pressure greater than Application of pressure greater than  osmotic pressure of solution osmotic pressure of solution  Diffusion of water but not salt through a Diffusion of water but not salt through a  semipermeable membrane in direction membrane in direction semipermeable opposite of natural flow opposite of natural flow  Crossflow Crossflow filtration to sweep away filtration to sweep away  concentrated salts concentrated salts 22

Reverse Osmosis: Reverse Osmosis: What It Can Do What It Can Do  Remove purified water from a feed stream Remove purified water from a feed stream  (permeate) (permeate)  Concentrate chemicals in a feed stream Concentrate chemicals in a feed stream  (reject) (reject)  Selectively separates small ions and Selectively separates small ions and  molecules molecules 23

Reverse Osmosis: Reverse Osmosis: What It Cannot Do What It Cannot Do  Cannot concentrate to 100% Cannot concentrate to 100%   Cannot separate to 100% Cannot separate to 100%   Cannot reject gases Cannot reject gases  and is and is Not always the most cost effective method Not always the most cost effective method 24

Mass Balance Equations Mass Balance Equations Permeate flow Permeate flow x 100 Recovery (%) = x 100 Recovery (%) = Feed flow Feed flow Permeate Salt Concentration Permeate Salt Concentration Salt Passage (%) = Salt Passage (%) = x 100 x 100 Feed Salt Concentration Feed Salt Concentration Salt Rejection (%) = 100 - - Salt Passage Salt Passage Salt Rejection (%) = 100 25

Normalization of Normalization of Field Operating Data Field Operating Data  Feedwater Feedwater pressure pressure   Temperature Temperature   Ionic concentration Ionic concentration   System recovery System recovery  26

pH vs vs Flux and Salt Rejection Flux and Salt Rejection pH 60 100 99 50 Salt Water Flux Rejection 98 (%) (GFD) 40 97 30 20 96 2 4 6 8 10 12 pH Data from DOW Filmtec 27

Pressure vs vs Flux+Rejection Flux+Rejection Pressure 100 40 99 30 Water Salt Flux Rejection (GFD) (%) 96 20 94 10 92 0 200 400 600 800 1000 1200 Pressure (PSI) Data from DOW Filmtec 28

Temperature v Temperature v Flux+Rejection Flux+Rejection 100 100 Water 99.5 80 Salt Flux Rejection (GFD) 99 (%) 60 98.5 40 98 20 10 20 30 40 50 60 Temperature (°C) Data from DOW Filmtec 29

Salinity vs vs Flux and Flux and Salinity Rejection Rejection 80 99.5 99 60 Water Salt Flux Rejection 98.5 (GFD) (%) 40 98 20 0 97.5 0 2 4 6 8 10 Percent Data from DOW Filmtec 30

Factors Which Affect Factors Which Affect Performance of Membranes Performance of Membranes  Feedwater Feedwater Pressure Pressure   Feedwater Feedwater Temperature Temperature   Feedwater Feedwater Concentration Concentration   Increased Recovery Increased Recovery  31

Simplified RO System Simplified RO System Feed Feed Water Water Permeate Permeate Pump Pump Concentrate Concentrate 100 to 400 psi psi (brackish water) (brackish water) 100 to 400 800 to 1,200 psi psi (seawater) (seawater) 800 to 1,200 32

Membrane Performance Membrane Performance Feed Permeate Reject (Brine) 33

Membrane Performance Membrane Performance 75% Recovery Feed Permeate 100 m 3 /hr 75 m 3 /hr Reject 25 m 3 /hr (Brine) 34