DESALINATION AND THERMAL DISTILLATION OF SEA WATER.
1. THE DESALINATION OF SEAWATER
THROUGH ELECTRODIALYSIS AND
THERMAL DISTILLATION
ENVIRONMENTAL ENGINEERING (CLE1006)
Under the guidance of Prof. DR.BHASKAR DAS
VELLORE INSTITUTE OF TECHNOLOGY, VELLORE
2. TEAM MEMBERS
• ALAN GEORGE 19BEI0001
• THOMAS TOM 19BEI0051
• MANASH KEDIA 19BCL0020
• RUDRAKSHALA SAI KIRAN 19BCL0028
• AAYUSH AGRAWAL 19BCL0050
• SMIT MUKESHBHAI PATEL 19BCL0057
• SHIVAM BHARDWAJ 19BEI0027
3. Water scarcity is a worldwide problem throughout
human evolution. Our future world will face this crisis
of freshwater resource exhaustion and environmental
degradation. It is estimated that water consumption
capacity will increase to 3800 km 3/year by 2025
according to recent investigation. Water scarcity will
become a crucial challenge in 21st century with the
explosion of global population within 5–6 decades.
5. Spanish region ship water to relieve drought
BY REPORT:
MADRID (Reuters) - Spain’s northeast Catalonia region will need to import
water by ship and train from May to ensure domestic supplies if the current
drought persists.
Drought in Spain’s northeastern region of Catalonia grew so severe in 2008
that Barcelona began importing water by ship from France. About 70 percent
of Spain’s water goes to agriculture, much of which is “wasted in antiquated
irrigation systems and the cultivation of thirsty crops unsuitable for arid
lands,” according to The Independent . Other critics pointed to low water
prices as the culprit for the crisis. Low water prices, it is often argued, result
in profligate water use and low investment in water-efficient infrastructure.
6.
7. NORTHERN INDIA’S GROUNDWATER LOSS
CAN BE SEEN FROM SPACE
TWIN SATELLITES FROM NASA’S GRAVITY RECOVERY AND CLIMATE EXPERIMENT (GRACE) ARE
ABLE TO DETECT CHANGES IN THE EARTH’S GRAVITY FIELD BROUGHT ABOUT BY CHANGES IN
MASS DISTRIBUTION, INCLUDING CHANGES IN GROUNDWATER STORAGE. NOWHERE ON EARTH
ARE GROUNDWATER DECLINES GREATER THAN IN NORTHERN INDIA; NASA FOUND THAT LARGE-
SCALE IRRIGATION CAUSED 108 CUBIC KILOMETERS OF GROUNDWATER LOSS IN HARYANA,
PUNJAB, RAJASTHAN, AND DELHI BETWEEN 2002 AND 2008. THE STUDY’S LEAD, MATT
RODELL, OBSERVED THAT “THE REGION HAS BECOME DEPENDENT ON IRRIGATION TO MAXIMIZE
AGRICULTURAL PRODUCTIVITY. IF MEASURES ARE NOT TAKEN TO ENSURE SUSTAINABLE
GROUNDWATER USAGE, THE CONSEQUENCES FOR THE 114 MILLION RESIDENTS OF THE REGION
MAY INCLUDE A COLLAPSE OF AGRICULTURAL OUTPUT AND SEVERE SHORTAGES OF POTABLE
WATER. "
https://www.wri.org/blog/2015/06/global-tour-7
9. California passed the Sustainable Groundwater Management
Act (Sgma), regulating groundwater for the first time in the
state’s history. Sgma was meant to limit industrial use of
groundwater while protecting the rights and resources of rural
residents who depend on shallow wells. But as the new
agencies tasked with managing the water drafted their plans,
residents were largely left out. Many of the plans meant to
protect groundwater would actually cause residential wells to
go dry as the water table continues to drop until Sgma’s 2040
sustainability deadline.
https://www.hcn.org/articles/climate-desk-thirsty-crops-and-vulnerable-families-vie-for-californias-precious-water
12. CARBON FOOTPRINT
OF DESALINATION
• High energy usage. Desalination
requires a substantial amount of
energy input to purify water for
drinking purposes
• High carbon emission. High energy
usage correlates with a greater
amount of emissions released.
Carbon emissions are commonly
associated with the disapproval of
desalination systems.
13.
14. Highlights
•Created for the first time, a tailor-made MRIO for a life cycle analysis
of 95% of desalination plants in Australia
•The electricity sector is the critical factor for environmental
sustainability
•Victoria is the country with the highest greenhouse gas emissions for
both capex and opex demand
•The electricity sector accounts for 69% of carbon dioxide emissions
during the combined construction and operation phase.
15. Seawater desalination is the removal of salt and impurities from seawater to
produce fresh water. Our desalination plants do this via a reverse osmosis
process.
Seawater is passed through a pre-treatment filter that removes large and
small particles. The filtered seawater is then forced under pressure through
special membranes whereby the osmosis process that normally occurs in
nature is reversed. The pores in the membranes are so tiny that salt,
bacteria, viruses and other impurities are separated from the seawater. In
essence they act like microscopic strainers. About half of the water that
enters the plant from the sea becomes fresh drinking water. The salt and
other impurities removed from the sea water is then returned to the ocean via
diffusers, which ensures it mixes quickly and prevents the marine
environment from being impacted.
The desalinated water is then subject to further treatment to meet drinking
water standards before it reaches our customers.
20. TREATMENT METHODS THERMAL
TECHNOLOGIES.
• MULTISTAGE FLASH DISTILLATION
• MULTI EFFECT DISTILLATION
• DIFFUSION DRIVEN DESALINATION
Thermal
processes (MSF,
MED, VC)
Membrane
processes (RO)
Typical salt
content of
feedwater (ppm)
30,000-100,000 1,000-45,000
Desalted water
with low total
dissolved solids
concentrations
(ppm)
10.0-20.0 100-550
Thermal energy
consumption
(kWh/m^3)
12 0
Energy
consumption
(kWh/m^32
17-18 2-6.7
Recovery Factor 40-50% 40-80%
Capital costs high low
Operating costs high low
21. WATER DESALINATION USING MULTI-STAGE FLASH
DISTILLATION (MSF)
• BEFORE REACHING THE BRINE HEATERS THE COLD SEA WATER PASSES THROUGH CONDENSING
COILS IN THE VACUUM FLASH CHAMBERS. THIS HAS THE DUAL FUNCTION OF
• PREHEATING THE COLD SEA WATER BEFORE ENTERING THE BRINE HEATER AND
• CONDENSING THE FLASHED STEAM IN THE CHAMBERS TO PRODUCE FRESH WATER.
• THE HOT BRINE THEN ENTERS THE FLASH CHAMBER WHICH IS AT A VACUUM. SINCE THE
ENTERING WATER TEMPERATURE IS HIGHER THAN THE BOILING TEMPERATURE AT THAT
VACUUM PRESSURE, A PART OF THE WATER FLASHES TO STEAM.
• THE STEAM RISES TO THE UPPER PART OF THE CHAMBER AND ON CONTACT WITH
CONDENSING COILS CONDENSES TO FORM PURE WATER. THE SALT AND OTHER IMPURITIES
STILL REMAIN WITH BALANCE OF THE BRINE AT THE BOTTOM OF THE CHAMBER. STEAM
EJECTORS PRODUCE THE NECESSARY VACUUM IN THE FLASH CHAMBERS.
• THE BALANCE BRINE GOES TO THE NEXT CHAMBER WHERE THE PROCESS REPEATS. MULTIPLE
CHAMBERS INCREASES THE QUANTITY OF THE WATER PRODUCT. THE BALANCE BRINE
RETURNS TO THE SEA. A 20 % YIELD OF FRESH WATER IS POSSIBLE IN MSF SYSTEMS.
22. THE ENERGY REQUIREMENT IS IN TWO STAGES:
• ELECTRICAL ENERGY FOR PUMPING THE
WATER.
• STEAM ENERGY FOR HEATING THE BRINE.
THE TOTAL ENERGY REQUIREMENT IS IN THE
ORDER OF 17 KWHR / M3 OF WATER.
FLASHING OF THE STEAM FORMS SCALES AND
DEPOSITS ON THE TUBES. PERIODIC CLEANING
AND REMOVAL IS REQUIRED.
https://www.brighthubengineering.com/power-plants/29623-how-desalination-by-multi-stage-
flash-distillation-works/
23. WATER DESALINATION USING MULTIPLE EFFECT DISTILLATION (MED)
• MULTIPLE EFFECT DISTILLATION WITH THERMAL VAPOUR COMPRESSION (MED-
TVC)
• MULTIPLE EFFECT DISTILLATION WITH MECHANICAL VAPOUR COMPRESSION
(MED-MVC)
• A MULTI EFFECT DESALINATION MED UNIT IS AN EVAPORATOR WHERE SEA WATER
IS EVAPORATED IN ONE OR MORE ( UP TO 14 ) EVAPORATION STAGES AT LOW
TEMPERATURE (< 70°C ) IN ORDER TO PRODUCE CLEAN DISTILLATE WATER.
MED PROCESS IS DESIGNED TO PRODUCE DISTILLED WATER WITH STEAM OR
WASTE HEAT FROM POWER PRODUCTION OR CHEMICAL PROCESSES, AND/OR TO
PRODUCE POTABLE WATER.
24. • STANDARD MED PROCESS SCHEME
• This Scheme represents a Multiple Effect
Distillation unit consisting of 3 cells
• In the last cell the produced steam is
condensed on a conventional shell and
tubes heat exchanger (distillate condenser)
cooled by sea water.
• At the outlet of the condenser, part of the
warmed sea water is used as make-up of
the unit, and part rejected to the sea. Brine
and distillate are collected from cell to cell
till the last one from where they are
extracted by centrifugal pumps
• The thermal efficiency of a unit is
quantified by the Gain Output Ratio
(GOR) defined as the quantity of distillate
produced per unit of heating steam used
https://www.veoliawatertechnologies.com/en/solutions/products/multiple-effect-
distillation-med
26. • DIFFUSION DRIVEN DESALINATION (DDD) PROCESS
IS PRESENTED, AND ITS PERFORMANCE BASED ON
THERMODYNAMIC CONSIDERATIONS IS
THOROUGHLY EXPLORED.
• THE DESALINATION IS DRIVEN BY WATER VAPOR
SATURATING DRY AIR FLOWING THROUGH A
DIFFUSION TOWER.
• LIQUID WATER IS CONDENSED OUT OF THE
AIR/VAPOR MIXTURE IN A DIRECT CONTACT
CONDENSER. THE DESALINATION PROCESS IS
SUITABLE FOR OPERATION AT LOW TEMPERATURES
AND MAY BE DRIVEN BY WASTE HEAT WITH LOW
THERMODYNAMIC AVAILABILITY.
• IT IS DEMONSTRATED THAT THE DDD PROCESS CAN
YIELD A FRESH WATER PRODUCTION EFFICIENCY OF
8% WITH AN ENERGY CONSUMPTION OF 0.05 KWH
PER KILOGRAM OF FRESH WATER PRODUCTION
Diffusion Driven Desalination.
28. REVERSE OSMOSIS
• REVERSE OSMOSIS WORKS BY USING A HIGH PRESSURE PUMP TO INCREASE THE PRESSURE ON
THE SALT SIDE OF THE RO
• THE FORCE MAKE WATER FLOW ACROSS THE SEMI-PERMEABLE RO MEMBRANE, LEAVING
ALMOST ALL (AROUND 95% TO 99%) OF DISSOLVED SALTS BEHIND IN THE REJECT STREAM.
• THE AMOUNT OF PRESSURE REQUIRED DEPENDS ON THE SALT CONCENTRATION OF THE
FEED WATER. THE MORE CONCENTRATED THE FEED WATER, THE MORE PRESSURE IS
REQUIRED TO OVERCOME THE OSMOTIC PRESSURE.
• THE DESALINATED WATER THAT IS DEMINERALIZED OR DEIONIZED, IS CALLED PERMEATE (OR
PRODUCT) WATER.
• THE WATER STREAM THAT CARRIES THE CONCENTRATED CONTAMINANTS THAT DID NOT
PASS THROUGH THE RO MEMBRANE IS CALLED THE REJECT (OR CONCENTRATE) STREAM.
29. • The pressure to overcome osmotic pressure, the water molecules pass
through the semi-permeable membrane and the salts and other
contaminants are not allowed to pass and are discharged through the reject
stream (also known as the concentrate or brine stream),
30. • FOR APPLIED DESALINATION TECHNOLOGY USED
CURRENTLY, RO PROCESS AS A STATE-OF-THE-ART
TECHNOLOGY SEAWATER DESALINATION PROCESS
ACCOUNTS FOR ABOUT 47.2% OF THE TOTALLY
INSTALLED DESALINATION CAPACITY
• SINCE RO POSSESSES SOME INHERENT SUPERIORITY
SUCH AS LOWER COST, PROCESS SIMPLICITY AND
ENVIRONMENT FRIENDLY
32. SALT REJECTION %
Salt Rejection % =
(Conductivity of Feed Water –
Conductivity of Permeate
Water) × 100
Conductivity of Feed
SALT PASSAGE %
Salt Passage % = (1 – Salt Rejection %)
RECOVERY %
% Recovery =
Permeate Flow Rate (gpm)
× 100
Feed Flow Rate (gpm)
33. FLUX
Gfd =
gpm of permeate × 1,440 min/day
# of RO elements in system × square footage
of each RO element
CONCENTRATION FACTOR
CONCENTRATION FACTOR= 1
1- recovery %
https://puretecwater.com/reverse-osmosis/what-is-reverse-osmosis
34. 1 AND 2 STAGE RO SYSTEM
• IN A ONE STAGE RO SYSTEM, THE FEED WATER ENTERS THE RO SYSTEM AS ONE
STREAM AND EXITS THE RO AS EITHER CONCENTRATE OR PERMEATE WATER.
• IN A TWO-STAGE SYSTEM THE CONCENTRATE (OR REJECT) FROM THE FIRST
STAGE THEN BECOMES THE FEED WATER TO THE SECOND STAGE. THE PERMEATE
WATER IS COLLECTED FROM THE FIRST STAGE IS COMBINED WITH PERMEATE
WATER FROM THE SECOND STAGE. ADDITIONAL STAGES INCREASE THE
RECOVERY FROM THE SYSTEM.
39. TWRO
Tap water
BWRO
Brackish water
SWRO
Sea water
Salinity < 1500 ppm < 8000 ppm 35000 - 45000 ppm
Recovery 80% 65-80% 35-45%
Working pressure < 15 bar 15-25 bar 50-75 bar
Membrane types Tap/Brackish 4" or 8" Seawater 4" or 8"
Flux 30-35 l/h.m2 25-30 l/h.m2 15-20 l/h.m2
Specific energy at 25
oC
< 0.75 kWh/m3 1.5 kWh/m3
5 kWh/m3 or 2-3
kWh/m3 with energy
recovery
Configuration Skid mounted or containerized (10 to 40 ft)
General design data for Reverse Osmosis Plants:
https://www.lenntech.com/systems/reverse-osmosis/ro/rosmosis.htm#ixzz6Gg4xocur
41. ELECTRODIALYSIS (ED).
• REVERSE OSMOSIS (RO) PROCESS IS THE MOST POPULAR SEAWATER DESALINATION
TECHNOLOGY TO SOLVE GLOBAL WATER CRISIS. HOWEVER, THE EFFLUENT OF CONCENTRATED
BRINE FROM RD PLANT COULD INDUCE SEVERE DAMAGE TO MARINE ECOSYSTEMS, ESPECIALLY
FOR CLOSED CONTINENTAL AREAS.
• ELECTRODIALYSIS (ED) AS AN EXCELLENT TECHNOLOGY HAS BEEN USED TO TREAT RD
EFFLUENT. AN ELECTRODIALYZER WHICH CONSISTED OF FIVE PIECES OF CATION-EXCHANGE
MEMBRANES (CEMS) AND FOUR PIECES OF ANION-EXCHANGE MEMBRANES (AEMS) WAS USED TO
TREAT CONCENTRATED BRINE OF RD PLANT.
• THE EFFECT OF OPERATION PARAMETERS SUCH AS CORREIA DENSITY, OPERATING MODE, TYPE
OF MEMBRANES AND INITIAL BRINE CONCENTRATION WAS INVESTIGATED TO MEASURE A LAB-
SCALE DEVICE.
• THE RESULTS INDICATE THAT WATER TRANSPORTATION PHENOMENON THROUGH ED PROCESS
ARE MAINLY INDUCED BY ELECTROOSMOTIC RATHER THAN OSMOTIC WATER TRANSFER CLUE
TO CONCENTRATION DIFFERENCE.
• THE ED PROCESS OF RD CONCENTRATED BRINE CAN PRODUCE BOTH REFRESH WATER AND
HIGHLY CONCENTRATED BRINE (CA. 27.13% (M/V)) FOR PRODUCING COARSE SALT VIA FURTHER
CRYSTALLIZATION.
42.
43. • ED PROCESS HAS BEEN USED TO TREAT VARIOUS
• FEED WITH DIFFERENT TYPES OF COMMERCIAL MEMBRANES.
• MEMBRANE PROPERTY HAS SIGNIfiCANT INflUENCE ON PROCESS COST AND fiNAL
DESALINATION EFfiCIENCY.
• TAKING THIS FACTOR INTO CONSIDERATION, A SERIES OF COMMERCIAL
MEMBRANES AND LAB-MADE MEMBRANE WERE INVESTIGATED FOR THE
TREATMENT OF RO CONCENTRATED BRINE
ELECTRO DIALYSIS, A COST-EFFECTIVE AND PROCESS AVAILABLE TECHNOLOGY TO
TREAT SALINE WATER, HAS BEEN WIDELY USED IN WATER TREATMENT, THE
PURIfiCATION OF BIOLOGICAL SOLUTIONS, FURTHERMORE, THE
DEMINERALIZATION OF MIXED SOLUTION. ED WAS REPORTED TO BE AN EFFECTIVE
METHOD TO TREAT RO EFflUENT
HTTPS://WWW.RESEARCHGATE.NET/PUBLICATION/269829883_ELECTRODIALYSIS_OF_CONCENTRATED_BRINE_FROM_RO_PLANT_TO_PROD
UCE_COARSE_SALT_AND_FRESHWATER
44. GENERAL CHARACTERISTICS OF ED ARE:
• POLARITY REVERSAL FEATURE TO AVOID SCALING
• LOW-PRESSURE OPERATION
• RELATIVELY LOW LIFECYCLE COST
• EASY MAINTENANCE
• LIMITED PRE-TREATMENT NEEDED
• CHLORINE COMPATIBLE
• BECAUSE AN ED SYSTEM REMOVES ONLY IONIZED SPECIES, IT IS PARTICULARLY SUITABLE
FOR SEPARATING NON-IONIZED FROM IONIZED COMPONENTS.
45. ELECTRO DEIONIZATION – EDI
ADVANCED ELECTRO DEIONIZATION (EDI) TECHNOLOGY IS
TYPICALLY IMPLEMENTED DOWNSTREAM OF REVERSE OSMOSIS
(RO) EQUIPMENT AND IS USED TO PRODUCE HIGH PURITY AND
ULTRA PURE WATER. AS THE SUCCESSOR TO MORE TRADITIONAL
ION EXCHANGE RESIN SYSTEMS, ENVIRONMENTALLY FRIENDLY EDI
SYSTEMS NOW SET THE STANDARD FOR DEMINERALIZED WATER
PRODUCTION. CONSUMING ONLY ELECTRICITY, EDI EQUIPMENT
CAN OPERATE CONTINUOUSLY, MAKING PURE PRODUCT WATER
OF CONSISTENT QUALITY, WITHOUT CHEMICAL WASTE. THE
SYSTEMS HAVE A VERY LIMITED FOOTPRINT AND FREQUENT
MAINTENANCE IS NOT REQUIRED.
46.
47. BENEFITS OF EDI:
• ENVIRONMENTAL FRIENDLY – NO REGENERATION CHEMICALS NEEDED
• EDI IS A CONTINUOUS PROCESS AND PRODUCES A CONSISTENT WATER
QUALITY
• EDI SYSTEMS ARE EXTREMELY COMPACT AND REQUIRE MINIMAL
FOOTPRINT
• LOW OPERATING COST (ELECTRICITY ONLY)
• CAPITAL COST IN LINE WITH TRADITIONAL TECHNOLOGIES
• MINIMUM FACILITY REQUIREMENTS AND OPERATOR ATTENTION
• HIGH SYSTEM RECOVERY, CONCENTRATE WATER RE-USED UPSTREAM
RO
• 1000’S OF SYSTEMS INSTALLED WORLDWIDE – UP TO A CAPACITY OF
1.500 M3/H
48. MEMBRANE DEGASSING
ALONG WITH OTHER PRE-TREATMENT STAGES, SUCH AS SOFTENING, MULTI-MEDIA
FILTRATION AND ULTRAFILTRATION. IT CAN BE USED TO INTRODUCE GASES TO A
LIQUID STREAM BUT MOST OFTEN, THEIR FUNCTION IS TO REMOVE DISSOLVED GAS
AND BUBBLES. IN THE CASE OF DRINKING WATER, HYDROGEN SULPHIDE IS
COMMONLY REMOVED AND IN MANY INDUSTRIAL APPLICATIONS, OXYGEN AND
CARBON DIOXIDE ARE THE TARGET GASES.
THE PRINCIPLE ADVANTAGES OF MEMBRANE DEGASSING ARE:
• CHEMICAL-FREE
• ENERGY EFFICIENT
• NOT RELIANT ON HEAT
• COMPACT EQUIPMENT
49. MEMBRANE DEGASSING UNITS (MDU) PROVIDE
AN EFFICIENT, COMPACT, AND MAINTENANCE-
FREE TECHNOLOGY TO REMOVE CARBON
DIOXIDE AND OXYGEN FROM WATER WITHOUT
ANY CHEMICAL TREATMENT.
50. FRESH WATER IS THE MAJOR PROBLEMS FACED BY THE WORLD’S
GROWING POPULATION. AS GLOBAL WATER RESOURCES DWINDLE,
THE ABUNDANCE OF AVAILABLE SEAWATER BECOMES AN OBVIOUS
OPTION TO FULFILL WATER REQUIREMENTS THROUGH
DESALINATION.
DESALINATION PLANTS HAVE EVOLVED RAPIDLY DURING THE LAST
TWO DECADES TO EXTRACT FRESH WATER FROM THE SEA.
CURRENTLY, APPROXIMATELY 150 COUNTRIES RELY ON
DESALINATION TO MEET THEIR FRESH WATER REQUIREMENTS.
GLOBALLY, AROUND 80 MILLION OF POTABLE WATER IS BEING
PRODUCED DAILY BY MORE THAN 17,000 DESALINATION PLANTS
AND OF THESE, 50% ARE UTILIZING SEA WATER AS THE SOURCE.
51. • 4.4% OF THE WORLD’S POPULATION INHABIT THE MIDDLE EAST,
BUT IT ONLY RECEIVES 1.1% OF THE GLOBAL RENEWABLE WATER
RESOURCES.
• 70% OF THE WORLD’S DESALINATION PLANTS ARE LOCATED IN
THE MIDDLE EAST.
• SAUDI ARABIA ALONE IS PRODUCING 20% OF THE WORLD’S
DESALINATED WATER.
• THERMAL DESALINATION AND REVERSE OSMOSIS (RO)
DESALINATION. BOTH ARE BEING USED IN THE MIDDLE EAST. SAUDI
ARABIA RUNNING THE WORLD’S LARGEST THERMAL DESALINATION
PLANT, PRODUCING (640,000 M3 PER DAY).
• GLOBALLY, 70% OF THE THERMAL DESALINATION PLANTS HAVE
ALREADY MOVED OVER TO RO BUT, IN THE MIDDLE EAST, ONLY
50% OF DESALINATED WATER IS TREATED IN THIS WAY BECAUSE
52.
53. • DESALINATION PLANTS OPERATE IN MORE THAN 120 COUNTRIES
IN THE WORLD, INCLUDING SAUDI ARABIA, OMAN, UNITED ARAB
EMIRATES, SPAIN, CYPRUS, MALTA, GIBRALTAR, CAPE VERDE,
PORTUGAL, GREECE, ITALY, INDIA, CHINA, JAPAN, AND AUSTRALIA.
• WORLDWIDE, DESALINATION PLANTS PRODUCE OVER 3.5 BILLION
GALLONS OF POTABLE WATER A DAY. THE INSTALLED RO
DESALINATION PLANT CAPACITY HAS INCREASED IN AN
EXPONENTIAL SCALE OVER THE LAST 30 YEARS.
• SEAWATER DESALINATION PROVIDES AN ACCESS TO NEW
UNTAPPED RESOURCES FOR A SUSTAINABLE AND DROUGHT PROOF
WATER SUPPLY.