反渗透 Reverse Osmosis - PowerPoint PPT Presentation

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反渗透 Reverse Osmosis

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  1. 反渗透Reverse Osmosis 基本原理 FUNDAMENTALS

  2. 过滤类型 Types of Filtration • 死端过滤 Direct Filtration • 沙或多介质 Sand or Multi Media • 滤筒 Cartridge • 横流过滤 Cross Flow Filtration • 反渗透 Reverse Osmosis • 纳滤 Nanofiltroation • 超滤 Ultra Filtration • 微滤 Micro Filtration

  3. 进水Feed Water 垂直过滤 Direct Filtration 产品水 Product Water

  4. 垂直过滤Direct Filtration Product 固体表面迅速形成过滤薄膜 Solids on surface quickly foul the membrane

  5. 反洗水排放 Back Wash to Sewer 垂直过滤 反洗 Back Wash

  6. 横流过滤 Cross Flow Filtration 渗透水Permeate 进水Feed Water 浓水Concentrate

  7. 渗透水Permeate 横流过滤 Cross Flow Filtration 膜表面 Membrane Surface

  8. 浓差极化Concentration Polarization

  9. 横流过滤Cross Flow Filtration 需求记住的事项Things to Remember • 进水速度必须能保证固体杂质的移动 • Water velocity of the feed must be sufficient to keep the solids moving. • 低流速会引起膜表面淤塞 • Low water velocity will allow the membrane surface to “foul.” • 较高的水回收率(更高的水利用率)意味着较低的水流速 • Higher water recoveries (greater water utilization) means lower water velocity.

  10. 过滤型谱 The Filtration Spectrum

  11. 横流过滤 Cross Flow Filtration • 反渗透 Reverse Osmosis • 溶解的固体杂质 Dissolved Solids • 纳滤 Nanofiltration • 二价离子 Divalent Ions (Ca & Mg) • 超滤 Ultrafiltration • 有机物和胶体 Organics & Colloids • 微滤 Microfiltration • 固体悬浮物 Suspended Solids

  12. 纯水水流 Pure Water Flow 渗透 Osmosis Osmotic Head H2O 纯水Pure Water 浓溶液 Strong Solution H2O H2O

  13. 平衡 Equilibrium 应用的压力 Applied Pressure, PF 渗透压力Osmotic Pressure, PO,F H2O 纯水 Pure Water Strong Solution H2O H2O Osmotic Pressure, PO,P 平衡 Equilibrium

  14. 反渗透 Reverse Osmosis Applied Pressure, PF 渗透水压力 Permeate Pressure, PP Osmotic Pressure, PO,F H2O Pure Water Strong Solution H2O H2O Osmotic Pressure, PO,P 纯水水流 Pure Water Flow

  15. 进水 Feed 渗透水Permeate Applied Pressure, PF Permeate Pressure, PP Osmotic Pressure, PO,F Osmotic Pressure, PO,P NDP 净推动压Net Driving Pressure (NDP)

  16. 净推动压 Net Driving Pressure • NDP = PF + PO,P - PP - PO,F • Available Pressure to “Drive” the Process • 含盐水 Brackish water PO,P = 0

  17. 各类化合物的渗透压 Osmotic Pressure of Various Compounds

  18. 渗透压 Osmotic Pressure • 100 ppm Salt 1 PSI Osmotic Pressure • 1000 ppm NaCl = 11.4 psi • 1000 ppm NaHCO3 = 12.8 psi • 1000 ppm Sucrose = 1.5 psi • 35,000 ppm Seawater = 374 psi »

  19. 水中的杂质 Impurities in Water • 离子类的 Ionic

  20. 阳离子阴离子 Ca+2 Cl- Mg+2 NO3- Na+ SO42- K+ HCO3- Fe+3 CO32- Mn+2 SiO2 Al3+ NH4+ PO43- • 离子的Ionic 水中的杂质 Impurities in Water

  21. 水中的杂质 Impurities in Water • 离子的 Ionic • 非离子的 • Non Ionic

  22. 有机物Organics • 酒精 Alcohols • 酮 Ketones • 醛 Aldehydes • 苯酚 Phenols • 离子的Ionic • 非离子的Non Ionic Impurities in Water

  23. Impurities in Water • Ionic • Non Ionic • 微粒的 Particulate

  24. Ionic • Non Ionic • 微粒的Particulate • 固体悬浮物Suspended Solids • 胶质物 Colloidal Material • 微生物 Microbiological • 细菌 Bacteria • 滤过性微生物/病毒Virus • 热原物质 Pyrogens • 藻类 Algae Impurities in Water

  25. 水中的杂质 Impurities in Water • Ionic • Non Ionic • Particulate • 气体类 Gases

  26. Ionic • Non Ionic • Particulate • 气体类Gases • 二氧化碳Carbon Dioxide • 氧 Oxygen • 氯 Chlorine • 氮 Nitrogen • 硫化氢 Hydrogen Sulfide 水中的杂质 Impurities in Water

  27. 反渗透可去除:Reverse Osmosis Removes • 离子类Ionic • 非离子类Non Ionic • 微粒的Particulate 不去除 气体类 Not Gases !

  28. 溶液中的离子 Ions in Solution • 化合物在水中电离 • Compounds dissolve in water to form charged ions • 阴离子 (负电 荷– 得到电子) • Anions (Negative Charge - extra electrons) • 阳离子 (正电 – 丢失电子) • Cations (Positive Charge - missing electrons)

  29. 离子 Ions • 丢失或得到一个电子的离子= 单价的 • Ions missing or having one electron = monovalent • 丢失或得到二个电子的离子= 二价的 • Ions missing or having two electrons = divalent • 丢失或得到三个电子的离子= 三价的 • Ions missing or having three electrons = trivalent

  30. 离子 Ions • 单价的 Monovalent: NaCl  Na+ + Cl- • 二价的 Divalent : CaSO4 Ca2+ + SO42- • 三价的 Trivalent : Na3PO4 3Na+ + PO43-

  31. 离子的相关渗透率Relative Permeation Rates of Ions • 一价的 Monovalent = 1 x 10-5 cm/sec 快 • 二价的 Divalent = 1 x 10-6 cm/sec • 三价的 Trivalent = 1 x 10-7 cm/sec 慢

  32. 离子 IonMg/l % Rejection 钠 Sodium 68.0 99.4 钾 Potassium 21.0 99.4 镁 Magnesium 21.0 99.8 钙 Calcium 80.0 99.8 硅酸 Silica 9.3 98.9 氯离子 Chloride 51.0 99.5 重碳酸根 Bicarbonate 132.0 99.3 硫酸根 Sulfate 163.0 99.8 TDS 528.0 99.6 典型离子脱出率Typical Passage of Ions Determined at 200 psi, 25% recovery, pH 7.8 on de-chlorinated city feed water with TFC membrane

  33. Things to Remember 应记住的事项Rejection Increases with Increasing脱盐率随下列变化 • Degree of dissociation电离程度 • Ionic charge离子电荷 • Molecular weight分子量 • Degree of molecular branching分子结构

  34. How small is small? InchesMeterMicrometer 39.37 1 1,000,000 3.94 .1 100,000 .39 .01 10,000 .04 .001 1,000 .004 .000,1 100 .000,4 .000,01 10 .000,04 .000,001 1 .000,008 .000,000,2 .1 5 x 10 -9 .005 UF 4 x 10 -10 .000,4 RO 1 Angstrom = 1 * 10 -10 m

  35. Salt Rejection H2O Membrane Cl- Na+

  36. Na+ H+ H+ H+ H+ H+ H+ H+ H+ O2- O2- O2- O2- 膜孔径 Membrane Pore Channel

  37. 反渗透 Reverse Osmosis 膜 Membranes

  38. 第一个RO膜 First RO Membrane ROGA Module #1 1964年

  39. Semi渗透膜Semi Permeable Membranes制造材料 Materials of Construction • 醋酸纤维素 Cellulose Acetate • TFC膜 Thin Film Composite • 聚酰胺 (Polyamide) • 聚砜Polysulfone

  40. 屏障层 Barrier Layer 分级的密度Graded-density cellulose acetate 支持Support 不均匀/不对称膜Asymmetric Membrane醋酸纤维素 Cellulose Acetate

  41. 聚酰胺超薄 屏障层 Polyamide Ultra-thin Barrier Layer 0.2 micron 多微孔聚砜 Microporous Polysulfone 40 micron 强化纤维Reinforcing Fabric 120 微米micron 薄膜合成物聚酰胺膜Thin Film Composite Polyamide Membrane Compaction is not an issue

  42. Barrier Layer 聚砜 Polysulfone 支持层 Support Layer

  43. Barrier Layer Polysulfone

  44. TFC 表面 Surface

  45. % Rejection = (TDSfeed - TDSProduct) x 100 TDSfeed % Salt Passage = TDSProduct x 100 TDSfeed 脱盐率 – 盐透过率Salt Rejection - Salt Passage

  46. 盐通量 Salt Flux Js = K2(Cm - Cp) Js = 盐通量 Salt Flux K2 = 传质系数 Mass Transfer Coefficient Cm = 膜上的浓度 Concentration at the membrane Cp = 渗透水的浓度 Concentration in the permeate

  47. Jw = K1( D P - D P) 水流量 Permeate Flux Jw = 水流量 Water Flux K1 = 系统常数/恒量System Constant P = 模跨膜压力 Transmembrane Pressure = 渗透压 Osmotic Pressure P

  48. 渗透水流量 Permeate Flux 通过一平方英尺膜面积的渗透水流速 The rate of permeate flow through one square foot of membrane. • 10 - 25 GFD • 温度 Temperature • 压力 Pressure

  49. CA 5 - 6.5 OK Good Low Excellent Good 104 $1.00 $1.00 膜参数对比Membrane Comparison 特点Characteristic TFC Opr. pH 2 - 11 Feed Pressure > 400 PSI < 200 PSI Salt Rejection 优 Excellent Water Flux 优 Excellent Bacteria Stability 高 High Cl Stability 差 Poor 2 Physical Stability 较好 Better o Max T ( F) 113 Element Cost * $1.50 System Cost * $1.16 * 有关费用 Relative Cost

  50. 膜特点和运行条件Membrane Characteristics and Typical Operating Conditions CA TFC Salt Rejection 90-96% > 99% Silica Rejection 85% 98% Nitrate Rejection 85% 94% Cl Tolerance 0.2 - 1.0 0 2 SDI Max 5 3 - 5 o Temp Range F) 32 - 95 32 - 113 Op. Pressure 400 < 200 pH Range 5-6.5 2 - 11 Flux Rate (GPD/Ft2) 12 - 16 15 -20 Bio Resistance 差 Poor Excellent rd 3 Year Compaction 20% 0 水解 Hydrolysis 2 X None