Saturated Sodium chloride brine can be produced by desalination of seawater.Such high purity brine will become the raw material for the production of Caustic soda and Soda ash.This slide show explains how.
1. CAPZ desalination
Clean Water At Affordable Price with Zero discharge)
A new patented desalination technology
20/08/2015 Clean Energy and Water Technologies, Australia
2. CAPZ desalination Overview
• Conventional desalination focuses on recovery of fresh water from
seawater using either RO or by thermal process.
• Conventional desalting focuses on recovery of Sodium chloride in the
form of concentrated brine using Electro-dialysis for the production of
Salt.
• CAPZ technology uses a patented technology that separates both
fresh water as well as Sodium chloride concentrate in the form of
brine.
20/08/2015 Clean Energy and Water Technologies, Australia
3. Conventional desalination
• The recovery of fresh water in a conventional SWRO process is restricted
to maximum 40% discharging 60% back into the sea with a more than
twice the salinity of seawater along with other chemical additives.
• Such a low recovery demands a very high volume of seawater intake and
concentrate discharge thus increasing the cost of project substantially.
• Such high salinity discharge contributes to global warming due to ocean
circulation and causes dwindling fish population threatening the marine life
as well as the change in climate we live in.
• Such a desalination technology is not only inefficient but highly polluting
and making product water expensive.
20/08/2015 Clean Energy and Water Technologies, Australia
4. Salt production using desalination
• Salt is produced from seawater predominantly using solar evaporation in
countries like Australia, India, China and Mexico.
• Solar evaporation uses huge area of arid land and employs manual labour
under harsh conditions.
• Solar evaporation is a very slow process that uses sun’s heat and wind
velocity and it takes nearly a year to harvest the salt.
• Solar salt contains number of impurities such as Calcium, Magnesium and
Sulphates and are not useful as a feed stock for chemical industries without
further purifications.
• More than 70% of salt produced in the world are used by chemical
industries. In Japan, Salt is mainly produced by Electro-dialysis of seawater.
20/08/2015 Clean Energy and Water Technologies, Australia
5. Why desalination technologies are
inefficient?
• Seawater contains 3.5% dissolved salts and 96.5% fresh water.
• Both fresh water and salts are useful.
• Separating 3.5% salt is easier than separating 96.5% fresh water from
seawater.
• But Separation of 3.5% salt does not solve the problem because it is
a mixture of salts and they need to be separated and purified to get
individual products of commercial value.
• Chemical industries such as Caustic soda and Soda ash plants use
Sodium chloride as the raw material. They require high purity salt.
20/08/2015 Clean Energy and Water Technologies, Australia
6. Continuation….
• Salt cannot be used in a crystalline or solid form in the chemical industries
but used in the form of brine.
• It is economical for chemical industries to use Sodium chloride in the form
of saturated brine.
• The cost of brine is expensive due to purification steps required to purify
the solar salt apart from high cost of transporting overlong distances, high
inventory cost, fluctuation in production due to erratic climate and
unseasonal rains etc. Caustic soda plants use large volume of salts on a
daily basis. An average salt consumption varies from 500Mt/day up to
3000Mt/day.
• The capital cost and running cost of brine preparation and purification are
very high making Caustic soda expensive.
20/08/2015 Clean Energy and Water Technologies, Australia
7. Continue….
• Chemical plants also require large volume of demineralized water
(DM water) to prepare a saturated Sodium chloride brine.
• They consume both salt and DM water on a daily basis. An average
consumption of demineralized water by chemical plants varies from
1700Mt/day to 10,000Mt/day.
• Therefore sea is the common source from which both fresh water as
well as Salts are produced.
• The demand by industries for fresh water creates shortage for
drinking water.
20/08/2015 Clean Energy and Water Technologies, Australia
8. Shortage of fresh water
• Bulk of the water is used by agriculture as well as industries. Due to
rapid industrialization and agriculture production there is a growing
demand for fresh water. During failure of monsoon rains in India the
demand for fresh water is high and shortage of water affects national
productivity drastically.
• The water table in many parts of India is dwindling and the depth of
bore wells have increased sharply resulting in increased power
consumption and competition among farmers in sharing the water.
Failure of crops and lack of productivity due to water shortage often
drive farmers to extremes and the suicide rate among the farmers in
India is one of the highest in the world.
20/08/2015 Clean Energy and Water Technologies, Australia
9. Demand for efficient desalination
technologies
• Fresh water with low scale forming minerals such as Calcium, Magnesium
and sulphate salts are in high demand by Power, Chemical, Pulp and Paper
and Agriculture industries. Both source of water and quality of water are
critical to industries. When surface and ground water sources are not
available, seawater is the only source for them.
• Fresh drinking water that meets WHO specification should have a TDS less
than 500 ppm; it should also be free from pathogens such as bacteria and
virus.
• Therefore there is a huge demand for an efficient desalination technology
that can recover maximum quantity of fresh water as well as salt
simultaneously from seawater. It is no longer economical just to recover
part of fresh water and discharging effluent back into the sea ; while
thousands of hectares of land are used to make low quality and low
productive salt that cannot meet the industries demand.
20/08/2015 Clean Energy and Water Technologies, Australia
10. CAPZ desalination technology
• CAPZ desalination is a new patented technology developed by an
Australian company CEWT (Clean Energy and Water Technologies)
• CEWT is based in Melbourne in the state of Victoria.
• CAPZ technology has been developed by in-house research and
development and tested in Japan on a pilot scale with capacity of
5m3/hr.
• The recovery of fresh water from CAPZ process is about 70% of the
seawater intake. It also generates simultaneously 4% Sodium chloride
brine with concentration from 25-30%.
20/08/2015 Clean Energy and Water Technologies, Australia
11. Pure water and Ultra pure brine
• CAZ technology can recover 70% of fresh water with TDS less than
300ppm from seawater ( TDS 35,000ppm) and also 4% Sodium
chloride brine of concentration (25-30% w/w).
• The Sodium chloride brine is relatively free from major impurities but
requires further purification to get ultra pure brine required by
Membrane electrolysis to produce Caustic soda and Soda ash by
Solvay process. A simple deionization using ion-exchange will produce
ultra pure brine demanded by modern industries.
• CAPZ technology uses NF for softening seawater reducing the TDS
level from 40,000ppm to 27,000ppm thereby reducing the osmotic
pressure for further processing.
20/08/2015 Clean Energy and Water Technologies, Australia
12. Electrodialysis
The electrodialyzer uses permselective ion
exchange membranes and electrical energy to
separate ionic substances in aqueous solution,
enabling efficient desalination, concentration,
refining and recovery.
Electrodialysis is a separation technology
utilizing electrophoresis of ionic substances
in solutions and the selective permeability of
ion exchange membranes. There are two
types of ion exchange membranes. Cation
exchange membrane selectively allows cation
permeation and anion exchange membrane
selectively allows anion permeation. In an
electrodialyzer, a large number of these
membranes are arranged alternately between
two electrodes and direct current is applied to
separate ions in solution
20/08/2015 Clean Energy and Water Technologies, Australia
13. Continue…
• The softened seawater is further subject to Electro-dialysis generating
concentrated Sodium chloride brine using ion selective membranes
thereby excluding divalent ions.
• The diluent from Electro-dialysis with TDS less than 20,000ppm is
further treated by RO (reverse osmosis) generating Fresh water with
TDS less than 300ppm and a concentrate with TDS 60,000ppm.
• The concentrate from RO is recycled back into the NF feed for further
softening and the process continues.
• In CAPZ process Sodium chloride brine is the main product and fresh
water is a by-product. This allows water to be priced cheaply.
20/08/2015 Clean Energy and Water Technologies, Australia
14. Comparing conventional SWRO with CAPZ
technology
Conventional SWRO 1000Mt/day plant
• Seawater intake 3000 Mt/day
• Concentrate discharge
2000Mt/day.
• By-product – Nil
• Sales revenue from water
$1250/day
CAPZ desalination 1000Mt/day
• Seawater intake 1430 Mt/day
• Concentrate discharge 286
Mt/day.
• By-product Sodium Chloride
brine (25-30%) 40Mt/day
• Sales revenue from water
$1250/day
• Sales from brine $ 2000/day
20/08/2015 Clean Energy and Water Technologies, Australia
15. Continue..
Conventional SWRO- 1000Mt/day
• Power consumption 4-5
Kwhr/m3.
• Capital cost is low.
• Pay back period is longer.
• Return on investment is low.
• Achieving ZLD is difficult
• No Possibility for more value
added product by expansion.
CAPZ desalination 1000Mt/day
• Power consumption 7-8
Kwhr/m3.
• Capital cost is high.
• Payback is shorter.
• Return on investment is high.
• Achieving ZLD is easier.
• Possibility to add more value
added products by expansion.
20/08/2015 Clean Energy and Water Technologies, Australia
16. Continue..
Conventional SWRO plant 1000Mt/day
• Environmentally harsh
contributing to global warming and
affecting marine life.
• Large seawater intake and large
ocean outfall affecting the
landscape and the surrounding
environment.
• High seawater intake and outfall
demands often open sea intake
deep inside the sea with dredging.
CAPZ desalination plant 1000Mt/day
• Environmentally friendly due to
less toxic and low effluent
discharge
• Low seawater intake and outfall
does not effect the surrounding
environment.
• Due to low seawater intake it is
possible to use sea well to achieve
low SDI and other low cost intake
arrangements.
20/08/2015 Clean Energy and Water Technologies, Australia
17. Contact for further
information
• CAPZ technology is ideal for the
following industries :
• Caustic Soda/Chlorine plants using
membrane electrolysis.
• Soda ash plants using Solvay process.
• Pulp and Paper Industries.
• Salt industries for production of Food
grade/Pharmaceutical grade salts.
• Power industries for boiler feed.
• Drinking water supply.
ahilan@clean-energy-water-tech.com
20/08/2015 Clean Energy and Water Technologies, Australia