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Horizontal filters for desalination. Horizontal filters for desalination. April 2010. 2010. Index. Introduction: Water problem Desalination. Water scarcity forecast Desalination. Mundial capacities Mundial investments desalination forecast Simplified diagram of a desalination facility
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Horizontal filters for desalination Horizontal filters for desalination April 2010 2010
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
Introduction: Water problem • One out of eight people lacks access to clean water. • 3.3 million die from water-related health problems each year. • 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.
Desalination. Water scarcity forecast • Year 2025 • Physical water scarcity • Economic water scarcity • Little or no water scarcity • Not estimated Source: International Water Management Institute
Desalination. Mundial capacities Source: German Desalination Society (DME)
Mundial investments desalination forecast Year Source: BBC Research, 2008
Three new technologies to reduce energy requirements FORWARD OSMOSIS CARBON NANOTUBES BIOMIMETICS
FILAMENT WINDING APRIL 2010
Index • Introduction: What it is? • Components of filament winding • Process • Properties • Materials selection • Advantages and disadvantages to other processes • Applications
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.
Components of filament winding • Roving creel and tensioners • Resin bath • Filament winding machine
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. Helical winding • Hoop winding
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)
Properties of Raw Fiber material • Glass: • - Cheap • - High strength • - Low stiffness • Carbon: • - High strength • - 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
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)
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
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
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…
Sand filter: External construction details Manhole Air relief Dirty water Rupture disc Foundations Manhole Water drain Base Air backwash Clean water
Sand filter: Internal constructions details, stresses and applied-loads Diffuser support Raw water diffuser Workingpressure P1=0,6 MPa Pressureundertheplate P2= P1- ΔP Differentialpressure in filtration PF=0,12 MPa Differentialpressure in backwash PL=0,1 MPa Pressure exerted by the weight of the sand Pm= 0,02 MPa Body filter Support nozzle plate for air backwash ϭ3 P1 ϭ1 ΔP PF Pm Air circulation Union P2 ϭ2 Nozzle plate PL Support nozzle plate for filtration Water circulation Air distributor
How does a sand filter with a nozzle plate work? 2 Water passes through the diffuser channel 3 Water through different size media 4 Water through the nozzles Raw water inlet 1 Air Backwash connection 5 Clean water free of suspended solids
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 Outlet Air Backwash connection Inlet
How does a sand filter with collector arms work? 2 Water passes through the diffuser channel 3 Water through different size media 4 Water through the collector arms Raw water inlet 1 Clean water free of suspended solids 5
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 Outlet Inlet
Nozzle plate versus collector arms • 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 Clean water Some dead areas due to a lack of water circulation Collector arms Nozzle plate Filter layout Nozzle plate Collector arms