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ChE-413: Desalination and Water treatment
Introduction
Water Desalination
Reverse Osmosis (RO)
•
Introduction
•
Historical Background
•
Principle of RO
•
Membrane Configuration
•
-…
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Osmosis is movement of water molecules from an area of low
concentration to an area of high concentration .
Reverse osmoses is a process that forces water molecules to flow against
a net osmotic pressure
With adequate pressure, reverse osmoses can remove purified water from
a sample containing higher concentrations of dissolved solids.
Any solution, no matter how dilute, eventually concentrates enough to
shut down a reverse osmosis system unless there is reject flow and
corresponding makeup (dilution flow) for the concentrate side.
Osmotic forces can accumulate to tremendous pressures if a solution
continues to increase in TDS.
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ChE-413: Desalination and Water treatment
Historical Background
ChE-413: Desalination and Water treatment
Historical Background
Osmosis: First reported by a French researcher – Abbe Nollet in 1748: water
diffuses from dilute to concentrated solution.
Research on Reverse Osmosis began in the 1950’s at the University of Florida
where Reid and Breton were able to demonstrate desalination properties of
cellulose acetate membrane.
Development of practical membrane processes
Membrane process
Year Application
Microfiltration (Germany)
1920 Laboratory use (bacteria filter)
Synthetic membranes were first introduced in modern separation process in
1960s.
Ultrafiltration (Germany)
1930 Laboratory use
Loeb-Sourirajan of UCLA in early 1960’s : Breakthrough discovery for
industrial membrane application: RO for desalination.
Hemodialysis (Netherlands)
1950 Artificial Kidney
1970s: Cellulose Acetate (CA) was the first invented RO membrane.
Electrodialysis (USA)
1955 Desalination
1980s: Linear Polyamide, Crosslinked Aromatic Polyamide (CAP) composite
membrane — has 4 to 5 times larger water flux, and better water quality than
CA
Reverse Osmosis (USA)
1960 Sea water desalination
Ultrafiltration (USA)
1960 Concentration of
macromolecules
So RO began to play an increasingly important role in the water desalination
in 1980s.
Membrane separation has become the main source of potable water
worldwide.
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ChE-413: Desalination and Water treatment
ChE-413: Desalination and Water treatment
What is Reverse Osmosis Process
What is Reverse Osmosis Process
A very fine filtering system
A very fine filtering system
Uses a membrane filter which allows water molecules
through but not salt
Uses a membrane filter which allows water molecules
through but not salt
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ChE-413: Desalination and Water treatment
Reverse Osmosis system
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ChE-413: Desalination and Water treatment
Membrane Separation Spectrum
The course of seawater in a desalination plant using RO
Different layers of the filter
The first filter gets the largest
objects out of the water
The last filter layer called the
membrane rejects the salt
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ChE-413: Desalination and Water treatment
Membrane Processes
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ChE-413: Desalination and Water treatment
Membrane Processes
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RO
NF
UF
MF
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ChE-413: Desalination and Water treatment
Membrane Processes
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ChE-413: Desalination and Water treatment
Membrane Processes
Filter type
Symbol
Pore Size,
µm
Operating
Pressure,
Types of Materials
Removed
psi
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Microfilter
MF
1.0-0.01
<30
Clay, bacteria,
large viruses,
suspended solids
Ultrafilter
UF
0.01-0.001
20-100
Viruses, proteins,
starches, colloids,
silica, organics,
dye, fat
Nanofilter
NF
0.001-0.0001
50-300
Sugar, pesticides,
herbicides,
divalent anions
Reverse
Osmosis
RO
< 0.0001
225-1,000
Monovalent salts
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ChE-413: Desalination and Water treatment
Principle of RO
ChE-413: Desalination and Water treatment
Principles of Natural Osmosis
1.
Osmosis is a purely natural process.
2.
Fluids with a low salt content will
always try to mix with fluids with a
high salt content until the salt
content of the two fluids is the
same.
3.
If the two fluids are separated by a
semi - permeable membrane, the
fluid with the low salt content will
permeate
(go
through)
the
membrane until the salt content is
the same at both sides of the
membrane.
4.
So, a greater number
of water molecules are
attracted to the higher
concentration side.
Hydrated ions
prevent them
migration
to
diluted side.
The level difference of the two
fluids is called the osmotic pressure.
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Water molecules is
attracted to ions on
both sides of the
membrane.
Electrostricted Zone
“Cluster” Zone
13
“Free Water”
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ChE-413: Desalination and Water treatment
Principles of Natural Osmosis ..cont.
Semipermeable
Membrane
1,000 ppm
NaCl Solution
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ChE-413: Desalination and Water treatment
Principles of Natural Osmosis …cont.
Pure Water
Semipermeable
membrane
Imagine a beaker
which is filled with
water and has a
tube that has been
half-submerged in
the water.
As expected, the
water level in the
tube and the beaker
will be the same.
Osmosis Causes Levels and
Concentration to Change
1. Salt Solution is Diluted
2. Pure Water Level Decreases
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from
the
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If we used a sealed
end tube (using semipermeable membrane)
has been partially filled with a salty
solution.
Semipermeable
membrane
Over time, something
unexpected happens
-- the water in the
tube actually rises.
The rise is attributed
to "osmotic pressure."
Initially,
the
level
inside and outside the
tube will be the same
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ChE-413: Desalination and Water treatment
Principles of Natural Osmosis …cont.
Principles of Natural Osmosis …cont.
5 psi
Hydrostatic
Head
10 psi
Net Osmotic Pressure
9 psi
11 feet
Osmotic Forces
10 psi
1 psi
1
psi
of
osmotic
pressure is caused by
every
100
ppm
difference in TDS.
Osmotic Forces
1 psi
5 psi
Hydrostatic
Head
11 feet
The force driving the
molecules from one
side to the other is
called
the
osmotic
pressure.
T=0
Initial
Conditions
Hydrostatic Head (Applied Pressure)
5 psi
5 psi
Driving Pressure
6 psi
15 psi
How can
osmoses cause
water to
apparently defy
gravity?
Net Driving Pressure
9 psi
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ChE-413: Desalination and Water treatment
Principles of Natural Osmosis …cont.
Principles of Reverse Osmosis
Final
Conditions
(equilibrium)
Solution A
220 ppm
TDS
T=O
Solution B
5,000 ppm
TDS
7.5 Psi
5.5 feet
2 psi
16.5 feet
2.5 Psi
Osmotic Forces
7 psi
Hydrostatic Head
2.5 psi
7.5 psi
Driving Pressure
9.5 psi
9.5 psi
Final equilibrium
condition
Osmotic Forces
50 psi
2 psi
Equilibrium is
reached when the
NDP goes to zero.
Net Osmotic Pressure
48 psi
We can reverse the
natural
osmosis
phenomena
by
applying a higher
pressure on the high
salt
concentration
side.
Net Driving Pressure (NDP) = O
Flow Stops
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Principles of Reverse Osmosis
ChE-413: Desalination and Water treatment
Principle of RO
Piston
100 psi
Additional
Applied
Pressure
5 psi
Hydrostatic
Head
5 psi
Hydrostatic
Head
11 feet
11 feet
T=O
Initial
Conditions
Osmotic Forces
50 psi
2 psi
Applied Pressure
5 psi
105 psi
The phenomena is explained
as when placing salt and pure
water on two sides of a semipermeable membrane; then
Driving Pressure
RO occur when
we apply
enough pressure
to cause +ve
net driving
pressure against
osmoses.
Pure water
Brine
There will be a natural
tendency of the pure water to
diffuse through the
membrane to the salt water
55 psi
107 psi
Net Driving Pressure
52 psi
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ChE-413: Desalination and Water treatment
Principle of RO - Equilibrium
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ChE-413: Desalination and Water treatment
Principle of RO – Applying Pressure
When a certain pressure is
applied to the saline water
side this diffusion is
stopped and an equilibrium
state is reached
If the pressure is increased
further , then the salt
water will now diffuse
through the membrane
towards the pure water,
rejecting the salt.
This equilibrium is achieved
when
∆P = ∆ π ( which is the
osmotic pressure)
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ChE-413: Desalination and Water treatment
Performance parameters
Osmotic and Operating Pressure
The RO process is defined in terms of a number of variables,
which include:
The osmotic pressure , π, of a solution can be determined
experimentally by measuring the concentration of dissolved
salts in the solution. The osmotic pressure is obtained from
the following equation
• Osmotic and operating pressure
• Salt rejection
π = R T ΣXi
• Permeate recovery
π = osmotic pressure , kPa
Membrane manufacturing companies define system
specifications in terms of the feed quality which includes
salinity and temperature
T = temperature, K
R = gas constant, 8.314 kpa m3/kgmol K
X = concentration of all constituents in solution, kgmol/m3
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ChE-413: Desalination and Water treatment
Osmotic Pressure
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ChE-413: Desalination and Water treatment
Osmotic Pressure
The osmotic pressure, Posm, of a solution can be determined
experimentally by measuring the concentration of dissolved salts in
solution :
Posm = 1.19 (T + 273) * Σ(mi) (1)
where
Posm = osmotic pressure (in psi),
T is the temperature (in °C), and
Σ(mi)=sum of molal concentration of all constituents in a solution.
An approximation for Posm may be made by assuming that 1000 ppm of
TDS equals about 11 psi (0.76 bar) of osmotic pressure.
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The mechanism of water and salt separation by reverse osmosis is not
fully understood.
Two transport models: porosity and diffusion.
Porosity : transport of water through the membrane may be through
physical pores present in the membrane.
Diffusion from one bonding site to another within the membrane.
The chemical nature of the membrane is such that it will absorb and pass
water preferentially to dissolved salts at the solid/liquid interface.
This may occur by weak chemical bonding of the water to the membrane
surface or by dissolution of the water within the membrane structure.
Either way, a salt concentration gradient is formed across the solid/liquid
interface. The chemical and physical nature of the membrane determines
its ability to allow for preferential transport of solvent (water) over
solute (salt ions).
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ChE-413: Desalination and Water treatment
Osmotic and Operating Pressure
Water
TDS mg/l
π, bar
Brackish
12000
7
Seawater
35000
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ChE-413: Desalination and Water treatment
Osmotic Pressure Estimation
Osmotic Pressure, π (atm) = M R T
where
π is the osmotic pressure in atm, M is Molarity
R is the universal gas constant, R = 0.0821 liter-atm/mole kelvin
T temperature in degree Kelvin
40
pi = 0.782 (PPM/1000) - 2.939
R2 = 0.9932
35
30
25
Seawater
(Arabian
Gulf)
20
Example
Calculate the osmotic pressure of a solution that contained 100 grams of NaCl
dissolved in enough water to make 1 liter of solution at 25 ◦C.
15
(North sea)
10
50000
37
5
1.
Convert the grams of NaCl to moles by dividing the grams by the molecular
weight of NaCl (58.5). (Na=23, Cl=35.5)
00 grams sucrose X 1 mole / 58.5 grams sucrose = 1.71 moles NaCl
2. Determine the Molarity concentration.
Molarity = moles NaCl / volume of solution in liters = 1.71 / 1 = 1.71 M
3. Convert the temperature from Celsius to Kelvin, K = 25 + 273 = 298 K
4. Calculate the osmotic pressure using the formula.
Osmotic pressure in atm = M R T = (1.71) (0.0821) (298) = 41.8 atm
0
0
10
20
30
40
50
60
An approximate of π may be made by assuming that 1000 ppm of
Total dissolved solids, TDS, equals 75.84 kPa of osmotic pressure
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Osmotic Pressure Correlation
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ChE-413: Desalination and Water treatment
Operating Pressure
Operating pressure is adjusted to overcome the adverse
effects of the following
The osmotic pressure, π, in bar is obtained from the data given by
Sourirajan (1970) for the NaCl–H2O system at 25 ◦C (concentration
range: 0–49.95 kgm−3) and is correlated as:
• Osmotic pressure
• Friction loss
• Membrane resistance
• Permeate pressure
If the operating pressure is set to equal to the net of all
above, then the net flow of the permeate across the
membrane would equal zero; therefore, the operating
pressure is set to higher value in order to maintain
economical permeate flow rate
Reference: Sourirajan, S. (1970). Reverse osmosis. New York: Academic.
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Water Transport
ChE-413: Desalination and Water treatment
Salt Passage
The rate of water passage through a semipermeable membrane is:
The rate of salt flow through the membrane is defined by :
Qw = ( ∆P - ∆Posm) * Kw * S/d
(2)
where
Qw is the rate of water flow through the membrane,
∆P is the hydraulic pressure differential across the membrane,
∆Posm is the osmotic pressure differential across the membrane,
Kw is the membrane permeability coefficient for water,
S is the membrane area, and d is the membrane thickness.
Qs = ∆C * Ks * S/d
Qs is the flow rate of salt through the membrane,
∆C is the salt concentration differential across the membrane,
Ks is the membrane permeability coefficient for salt,
S is the membrane area, and d is the membrane thickness.
This equation is often simplified to:
This equation is often simplified to:
Qs = B*(∆C)
Qw = A * (NDP)
(3)
Where
A represents a unique constant for each membrane material type, and
NDP is the net driving pressure or net driving force for the mass transfer of
water across the membrane.
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Where
B represents a unique constant for each membrane type, and
∆C is the driving force for the mass transfer of salts.
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Salt Passage
Equations 4 and 5 show that for a given membrane:
1. Rate of water flow through a membrane is proportional to net driving
pressure differential (NDP) across the membrane.
2. Rate of salt flow is proportional to the concentration differential across the
membrane and is independent of applied pressure.
Salinity of the permeate, Cp,
depends on the relative rates of water and salt transport through reverse
osmosis membrane:
Cp = Qs/Qw
(6)
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Salt passage: is the ratio of concentration of salt on the permeate side of
the membrane relative to the average feed concentration. expressed:
SP = 100% * (Cp/Cfm)
(7)
where
SP is the salt passage (in %), Cp is the salt concentration in the permeate,
Cfm is the mean salt concentration in feed stream.
The fact that water and salt have different mass transfer rates through a
given membrane creates the phenomena of salt rejection. No membrane is
ideal in the sense that it absolutely rejects salts; rather the different
transport rates create an apparent rejection. The equations 2, 4 and 5
explain important design considerations in RO systems. For example, an
increase in operating pressure
will increase water flow without changing salt flow, thus resulting in lower
permeate salinity.
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ChE-413: Desalination and Water treatment
Salt Transport
(5)
ChE-413: Desalination and Water treatment
(4)
where
35
Applying the fundamental equations of water flow and salt flow
illustrates some of the basic principles of RO membranes.
For example, salt passage is an inverse function of pressure; that is, the
salt passage increases as applied pressure decreases. This is because
reduced pressure decreases permeate flow rate, and hence, dilution of
salt (the salt flows at a constant rate through the membrane as its rate of
flow is independent of pressure).
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ChE-413: Desalination and Water treatment
Salt Rejection
ChE-413: Desalination and Water treatment
Salt Rejection
Salt rejection is defined by
Salt rejection: is the opposite of salt passage, and is defined by:
SR = 100% (1-Xp/Xf)
SR = 100% - SP
(8)
where
SR is the salt rejection (in %), and
SP is the salt passage as defined in Equation 7:
SP = 100% * (Cp/Cfm) (7)
Xp = permeate concentration
Xf = feed concentration
Example:
A feed seawatrer with 42,000 ppm and a permeate with a
salinity of 150 ppm then the SR = 99.64%.
Current membrane technology provides a salt rejection above
99%.
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ChE-413: Desalination and Water treatment
Permeate Recovery Rate (Conversion)
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ChE-413: Desalination and Water treatment
Permeate Recovery
Permeate Recovery: is an important parameter in the design and operation
of RO systems.
Recovery or conversion rate of feed water to permeate is defined by:
Recovery or conversion rate of feed water to
product ( permeate) is defined as
R = 100% * (Qp/Qf)
(9)
where
R is recovery rate (in %),
Qp is the product water flow rate, and
Qf is the feed water flow rate.
The recovery rate affects salt passage and product flow. As the recovery
rate increases, the salt concentration on the feed-brine side of the
membrane increases, which causes an increase in salt flow rate across the
membrane as indicated by Equation 5: Qs = B*(∆C).
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R = 100% (Mp/Mf)
Mp = the permeate water flow rate
Mf = the feed water flow rate
Also, a higher salt concentration in the feed-brine solution increases the
osmotic pressure, reducing the NDP and consequently reducing the product
water flow rate according to Eq. 2: Qw = ( ∆P - ∆Posm) * Kw * S/d
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ChE-413: Desalination and Water treatment
Permeate Recovery .. Cont.
Concentration Polarization
As the recovery rate increases
• The salt concentration on the feed-brine side of the membrane
increases, which causes the increase of salt flow rate across
the membrane
As water flows through the membrane and salts are rejected by the
membrane, a boundary layer is formed near the membrane surface in which
the salt concentration exceeds the salt concentration in the bulk solution.
This increase of salt concentration is called concentration polarization. The
effect of concentration polarization is to reduce actual product water flow
rate and salt rejection versus theoretical estimates.
A higher salt concentration in the feed-brine side
• Increases the osmotic pressure thus reducing the product
water flow rate
Membrane recovery can reach up to 50%
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ChE-413: Desalination and Water treatment
Concentration Polarization
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ChE-413: Desalination and Water treatment
Concentration Polarization
The effects of concentration polarization are as follows:
1. Greater osmotic pressure at the membrane surface than in the
bulk feed solution, ∆Posm, and reduced Net Driving Pressure
differential across the membrane (∆P - ∆Posm).
2. Reduced water flow across membrane (Qw).
3. Increased salt flow across membrane (Qs).
4. Increased probability of exceeding solubility of sparingly soluble
salts at the membrane surface, and the distinct possibility of
precipitation causing membrane scaling.
The Concentration Polarization Factor (CPF) can be defined as a
ratio of salt concentration at the membrane surface (Cs) to bulk
concentration (Cb).
CPF = Cs/Cb
(10)
Salt concentrations build up at the membrane-water interface.
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ChE-413: Desalination and Water treatment
Concentration Polarization
RO Membrane
An increase in permeate flux will increase the delivery rate of ions to the
membrane surface and increase Cs. An increase of feed flow increases
turbulence and reduces the thickness of the high concentration layer
near the membrane surface. Therefore, the CPF is directly proportional
to permeate flow (Qp), and inversely proportional to average feed flow
(Qfavg).
Made from a thin film of polymeric material (several thousands
angstrom) which cast on polymeric porous material
Commercial membranes have high water permeability; the rate
of water permeability must be much higher than salt
permeability
CPF = Kp * exp(Qp/ Qfavg) (11)
Where
Kp is a proportionality constant depending on system geometry.
ChE-413: Desalination and Water treatment
Must be stable over a wide range of pH and T
Must have good mechanical integrity
Life of commercial membranes = 3-5 years
Using the arithmetic average of feed and concentrate flow as average
feed flow, the CPF can be expressed as a function of the permeate
recovery rate a of membrane element (Ri).
Major types of commercial membranes are cellulose acetate (CA)
and polyamides (PA)
CPF = Kp * exp(2Ri/(2-Ri)) (12)
The value of the Concentration Polarization Factor of 1.20, which is the
recommended Hydranautics limit, corresponds to 18% permeate recovery
for a 40" long membrane element.
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ChE-413: Desalination and Water treatment
Hollow Fine Fiber (HFF)
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ChE-413: Desalination and Water treatment
Hollow Fine Fiber (HFF)
Design of the HFM is akin to a large electrical cable: You have an
outer shell (a single nonporous material) through which the
materials inside cannot be transported. Inside that shell, there
are many thin fibers running the length of the shell, all in nice,
neat rows.
What occurs is that the source phase is piped through the system
from one side, and the pores in the fibers themselves will allow
the water to permeate to the annulus but not the salt.. The
concentrate will leave from the end of the tube.
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Hollow Fine Fiber (HFF)
ChE-413: Desalination and Water treatment
Spiral Wound membrane (SW)
The spiral wound membrane is essentially a flat membrane sandwich,
wrapped around a perforated tube, through which the effluent
emerges out of the membrane.
That sandwich is actually made of four layers; a membrane, a feed
channel, another membrane, and a permeate channel, which
forces all the separated material towards that perforated tube in
the center.
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ChE-413: Desalination and Water treatment
Spiral Wound Module
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ChE-413: Desalination and Water treatment
Spiral Wound membrane (SW)
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ChE-413: Desalination and Water treatment
Spiral Wound membrane (SW)
ChE-413: Desalination and Water treatment
Spiral Wound membrane (SW)
Permeate
Anti-Telescoping Caps
Perforated
Product Tube
Concentrate
Feedwater
Carrier
Sealed (glued) Edge of
Permeate Envelope
Feed
Solution
Permeate Flow
(after passing through
Membrane, shown
With blue arrows)
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Semipermeable
Membrane
Permeate
Carrier Material
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ChE-413: Desalination and Water treatment
Spiral Wound membrane (SW)
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ChE-413: Desalination and Water treatment
Tubular Module
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ChE-413: Desalination and Water treatment
Membrane Materials
ChE-413: Desalination and Water treatment
Membrane Polymers
Cellulose Acetate and Derivatives
Made from a thin film of polymeric material (several thousands
angstrom) which cast on polymeric porous material
Commercial membranes have high water permeability; the rate
of water permeability must be much higher than salt
permeability
Must be stable over a wide range of pH and T
Polyamides
Must have good mechanical integrity
Life of commercial membranes = 3-5 years
Major types of commercial membranes are cellulose acetate (CA)
and polyamides (PA)
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ChE-413: Desalination and Water treatment
Thin-Film Composite Membranes
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ChE-413: Desalination and Water treatment
Transport Phenomena –Flow Configuration
P o ly e ster
F ib er
B a ck in g
~120 µm
Machinery
P o ly su lfo n e
S u p p o rt
~50 µm
A ctiv e
N F /R O
L ayer
Directional flow
P o ly su lfo n e L ay e r
P o re S ize
~ 2 0 -3 0 n m
A c tiv e
L ay er
~ 5 0 -2 5 0 n m
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Transport Phenomena – Cross Flow Configuration
ChE-413: Desalination and Water treatment
Transport Phenomena – I
Steps:
• Transport in Bulk Feed
Solution
Bulk
Feed
Water
• Concentration-polarization
cf
• Sorption at
Feed/Membrane Interface
Note about notations:
• Diffusion within Membrane
Qi = M i
• Desorption at
Permeate/Membrane
Interface
c i = Xi
RO/NF
Membrane Jv
cw
c wm
cp
x
δ
c mp
∆x
Chemical Engineering Dep.
King Saud University
61
Chemical Engineering Dep.
King Saud University
ChE-413: Desalination and Water treatment
Transport Phenomena – II
Bulk
Feed
Water
J v = A[( p f − p p ) − (π w − π p )]
cw
Js
Laminar
Film
Product
Water
A: water permeation coefficient
(∝KDm/∆x)
p: hydraulic pressure
π: osmostic pressure
cp
x
δ
π w, f , p = RTcT ,w, f , pφ
c mp
∆x
R: ideal gas constant
T: temperature
cT: total concentration of dissolved
molecules and ions
φ: osmotic coefficient
Chemical Engineering Dep.
ChE-413: Desalination and Water treatment
where
c wm
62
Parameters Affecting RO Membrane Performance
Water Flux (Jv):
RO/NF
Membrane Jv
cf
Uf
Js
Laminar
Film
Uf
Product
Water
King Saud University
63
Operating Conditions
Water Quality Characteristics
Membrane Properties
– Charge
– Hydrophobicity/philicity
– Pore Size Distribution
– Integrity
Membrane Stability
– Hydrolysis/Oxidation
– Compaction
Interfacial Processes
– Chemical Fouling/Biofouling
– Concentration Polarization
– Scaling
Chemical Engineering Dep.
B ulk
F eed
W ater
R O /N F
M em brane J v
cw
cf
Uf
c wm
Product
W ater
Js
Lam inar
Film
cp
x
δ
c mp
∆x
B ulk
F eed
W ater
cw
Lam inar
Film
cf
Uf
RO /N F
Jv
M em brane
c wm
Product
W ater
Js
Fouling
Layer
cp
c mp
x
∆x
King Saud University
64
16
1/10/2011
ChE-413: Desalination and Water treatment
Reverse Osmosis unit
ChE-413: Desalination and Water treatment
RO Pressure Vessel with a flow Path Identified
Control
Panel
Membrane
Pressure
Indicator
Brine
Seal
Membrane
Element
Pressure
Vessel
Concentrate
Feed
Permeate
Membrane
RO High
Pressure
Pump
Low Pressure
Priming Pump
Chemical Engineering Dep.
King Saud University
65
Chemical Engineering Dep.
ChE-413: Desalination and Water treatment
RO Pressure Vessel with a flow Path Identified
King Saud University
66
ChE-413: Desalination and Water treatment
RO Pressure Vessel with a flow Path Identified
Pressure vessel with three membrane elements
RO Pressurized Vessel Structure
Chemical Engineering Dep.
King Saud University
67
Chemical Engineering Dep.
King Saud University
68
17
1/10/2011
ChE-413: Desalination and Water treatment
Typical RO Membrane Pressure Vessel
ChE-413: Desalination and Water treatment
Typical RO system and components
Membrane
Housing
Feed
Product
Reject
Submersible
Pump
Skid
Chemical Engineering Dep.
King Saud University
69
Chemical Engineering Dep.
King Saud University
ChE-413: Desalination and Water treatment
Typical RO system and components
ChE-413: Desalination and Water treatment
Typical RO system and components
Flow diagram of a two stage RO system
Chemical Engineering Dep.
70
Flow diagram of a three stage RO system
King Saud University
71
Chemical Engineering Dep.
King Saud University
72
18
1/10/2011
ChE-413: Desalination and Water treatment
ChE-413: Desalination and Water treatment
Typical RO system and components
Stack of Pressure Vessel
Chemical Engineering Dep.
King Saud University
73
Chemical Engineering Dep.
ChE-413: Desalination and Water treatment
King Saud University
74
ChE-413: Desalination and Water treatment
Typical RO system and components
Seawater intake pumps
Tampa, Florida USA, Feed water – Gulf of Mexico 26,000 – 28,000 mg/L
Chemical Engineering Dep.
King Saud University
75
Chemical Engineering Dep.
King Saud University
76
19
1/10/2011
ChE-413: Desalination and Water treatment
Typical RO system and components
Chemical Engineering Dep.
ChE-413: Desalination and Water treatment
Typical RO system and components
King Saud University
77
Chemical Engineering Dep.
ChE-413: Desalination and Water treatment
Typical RO system and components
Chemical Engineering Dep.
King Saud University
78
ChE-413: Desalination and Water treatment
Typical RO system and components
King Saud University
79
Chemical Engineering Dep.
King Saud University
80
20