Horizontal filters for desalination April 2010 Horizontal filters for desalination 2010

2 Index Introduction: Water problem Desalination. Water scarcity forecast Desalination. Mundial capacities Mundial investments desalination forecast Simplified diagram of a desalination facility Reverse osmosis desalination costs analysis Three new technologies to reduce energy requirements Filament winding Sand filter: External / Internal constructions details How does a sand filter work? Nozzle plate versus collector arms GFRP filters versus carbon-steel filters

3 Introduction: Water problem 46 percent of people on earth do not have water piped to their homes. In 15 years, 1.8 billion people will live in regions of severe water scarcity. One out of eight people lacks access to clean water. 3.3 million die from water-related health problems each year.

4 Desalination. Water scarcity forecast Source: International Water Management Institute Year 2025 Physical water scarcity Economic water scarcity Little or no water scarcity Not estimated

5 Desalination. Mundial capacities Source: German Desalination Society (DME)

6 Mundial investments desalination forecast Source: BBC Research, 2008 Year

7 Simplified diagram of a desalination facility

8 Reverse osmosis desalination costs analysis (1/3)

9 Three new technologies to reduce energy requirements FORWARD OSMOSIS CARBON NANOTUBES BIOMIMETICS

FILAMENT WINDING APRIL 2010

11 Index Introduction: What it is? Components of filament winding Process Properties Materials selection Advantages and disadvantages to other processes Applications

12 Introduction Filament winding is a technology to manufacture compound materials Quick and precise process. Most of the production process is automatic The pieces obtained have big mechanical properties and high resistance to corrosion.

13 Components of filament winding Roving creel and tensioners Resin bath Filament winding machine

14 Process It is a process by which continuous resin-impregnated reinforcements are wound over a rotating mandrel. The mandrel can be cylindrical, spherical, or any other shape as long as it does not have re-entrant curvature. The tension on the filaments can be carefully controlled. The filaments are applied with high tension in a final product with higher strength and rigidity. The filaments are applied with low tension in a final product with more flexibility. The orientation of the filaments can also be carefully controlled. Hoop winding Helical winding

15 Process The angle at which the fiber is laid down will determine the properties of the final product. Angles of fiber can be obtained between almost 90º and 25º to the axis Closed fiber angles provide great resistance to internal pressure (used in pressure tanks) With an angle of 45º provide resistance combined to shear (axes of transmission)

16 Mechanical properties StrengthStrong as high strength steels StiffnessGreater than most metals (per unit weight) Lightweight 80% lighter than steel 40% lighter than aluminum Fatigue resistanceExtended life CreepNegligible ToughnessAs damage tolerant as metals Corrosion resistance Fibers inert Resins chosen depending on the needs Dimensional stability Carbon composites can be designed for near zero coefficient of thermal expansion Noise and Vibration transmissionHigh damping coefficient

17 Properties of Thermoset Systems Service Temperature Elongation at Break Strength ºC%MPa Polyester603 Vinylester Epoxy Phenolic ,520-60

18 Properties of Raw Fiber material Glass: - Cheap - High strength - Low stiffness Carbon: - High strength - Lower density than glass - Expensive - Up to 3000ºC Aramid: - Good impact resistance - Should only be pulled - Not compressed - Expensive - Solvent at 300ºC Other fibres (Polyethylene, Boron….) - specific properties - expensive

19 Material Selection - Fiber choice Glass for: - Low cost - Transparency - Corrosion resistance - High deformations Carbon for: - Strength - Stiffness - Creep - Fatigue strength Aramid for: - Toughness (pressure vessels)

20 Material Selection - Resin choice Polyester for: - Low cost - Light translucency Phenolic for: - Fire resistance - High temperature Epoxy for: - Mechanical propierties - Toughness Vinylester for: - Corrosion resistance - High Chemical resistance

21 Filament winding advantages Highly repetitive in fiber placement (part to part, layer to layer) The use of continuous fibers over whole component area (without joints) Depending on the needs can orient the fibers easily Avoids capital expense of autoclave Structure can be built larger than autoclave size limits Mandrel costs can be lower than other tooling costs Costs relatively low for materials Rapid and precise process. No conductivity Weight Strength Corrosion Resistance Process Flexibility Fibers aligned for load or stiffness

22 Applications Oilfield Energy storage and Generation Flywheel, wind energy generation, gas storage… Communication Satellite Aerospace Aviation Marine Aerodynamic applications Chemical industry Automotive Industrial equipment Tanks and silos Sports goods Racquet, bicycle, golf shafts, surf, fishing rods…

23 Sand filter: External construction details Air relief Water drain Manhole Foundation s Manhole Base Air backwash Dirty water Clean water Rupture disc

24 Sand filter: Internal constructions details, stresses and applied-loads Working pressure P 1 =0,6 MPa Pressure under the plate P 2 = P1- ΔP Differential pressure in filtration P F =0,12 MPa Differential pressure in backwash P L =0,1 MPa Pressure exerted by the weight of the sand P m = 0,02 MPa PFPF PLPL P1P1 P2P2 ΔPΔP ϭ1ϭ1 ϭ2ϭ2 ϭ3ϭ3 Raw water diffuser Body filter Support nozzle plate for air backwash Water circulation Air distributor Air circulation Diffuser support Nozzle plate Union PmPm Support nozzle plate for filtration

25 Air Backwash connection Clean water free of suspended solids How does a sand filter with a nozzle plate work? Raw water inlet Water passes through the diffuser channel 1 2 Water through different size media 3 Water through the nozzles 4 5

26 Air Backwash connection Inlet Outlet How does a sand filter with a nozzle plate work? Backwash: air application through the air connection for a better expansion and cleaning of the media

27 How does a sand filter with collector arms work? Clean water free of suspended solids Raw water inlet Water passes through the diffuser channel 1 2 Water through different size media 3 Water through the collector arms 4 5

28 Inlet Outlet How does a sand filter with collector arms work? Backwash: water enters and passes through the same stages of the tank in reverse sense from the regular working procedure

29 Advantages of using a strainer nozzle plate collector in relation to the conventional collector arms system:  Possibility of air wash with the consequent saving of clean water.  There are no zones with stagnated water as the clean water is collected from the false bottom.  Optimum washing of the filtration bed with uniform distribution of the water. Nozzle plate versus collector arms

30 Nozzle plate versus collector arms Nozzle plate Collector arms Filter layout Nozzle plate Collector arms Clean water Some dead areas due to a lack of water circulation

31 GFRP filters versus carbon-steel filters