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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 - PowerPoint PPT Presentation
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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 scarcityEconomic water scarcityLittle or no water scarcityNot estimated
5
Desalination. Mundial capacities
Source: German Desalination Society (DME)
6
Mundial investments desalination forecast
0
5001000
1500
20002500
3000
35004000
Mili
ons
$
2000 2005 2007 2012
Any
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
Strength Strong as high strength steels
Stiffness Greater than most metals (per unit weight)
Lightweight80% lighter than steel40% lighter than aluminum
Fatigue resistance Extended life
Creep Negligible
Toughness As damage tolerant as metals
Corrosion resistanceFibers inertResins chosen depending on the needs
Dimensional stability Carbon composites can be designed for near zero coefficient of thermal expansion
Noise and Vibration transmission High damping coefficient
17
Properties of Thermoset Systems
Service TemperatureElongationat Break
Strength
ºC % MPa
Polyester 60 3 60
Vinylester 80 4-6 80
Epoxy 100 2-10 50-100
Phenolic 120-170 -1,5 20-60
18
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
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
FoundationsManhole
BaseAir backwash
Dirty water
Clean water
Rupture disc
24
Sand filter: Internal constructions details, stresses and applied-loads
Working pressure P1=0,6 MPa
Pressure under the plate P2= P1- ΔP
Differential pressure in filtration PF=0,12 MPa
Differential pressure in backwash PL=0,1 MPa
Pressure exerted by the weight of the sand Pm= 0,02 MPa
PF
PL
P1
P2
ΔPϭ1
ϭ2
ϭ3
Raw water diffuserBody filter
Support nozzle plate for air backwash
Water circulation Air distributor
Air circulation
Diffuser support
Nozzle plate
Union
Pm
Support nozzle plate for filtration
25
Air Backwash
connectionClean 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 media3
Water through the nozzles
4
5
26
Air Backwash
connectionInlet
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 media3
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
0
1
2
3Temperature
Maintenance
Thermal expansionWeight
Traction resistance
Carbon-steel
GFRP