TECHNICAL FIELD OF THE INVENTION
The present subject matter described herein, in general, relates to the field of
desalination, and more particularly to a system, and method for desalination of water by
using waste heat of flue gas from power plants to produce de-mineralized water.
10 BACKGROUND
Conservation of the fossils (e.g. coal) and water is important for nation’s energy
security. The power plants are the industrial utilities for the conversion of these fossils
and/or water for the generation of required usable energy, such as electricity. However,
15 fossil fired power plant loose huge amount of thermal (heat) energy in the exhaust of
flue gases. Apart from fossils (fossils fuels), other important consumable item in power
plants is water, which is mainly used for making steam and for cooling purpose, which
needs to be conserved and re-used.
20 The waste heat recovery of the power plants is a highly researched subject area.
However, there are only limited instances of the water desalination system, to re-use the
water, by utilizing waste heat of the fossil fired power plant.
In the prior art document, US8545681B2 patent is provided a desalination method from
25 waste heat recovery. The method integrates thermal desalination plant in combined
cycle power plant. It consist of making of de-saline water by means of thermally driven
applications called ‘effect’ (like condenser) by giving the initial steam from the waste
heat of the gas turbine plant. The first source is from ‘intercooler’ heat exchanger where
heated water is passed to flash tank and then the produced vapor is transferred to the
30 desalination to the ‘effect’. Another source of heat is steam exhausted from steam
3
turbine set is directly transferred to the desalination ‘effect’. The system prepares only
distilled water and involves single effect desalination.
In the prior art patent document, US8282791B2 titled “Desalination using low grade
thermal energy” is provided low grade heat (40 to 50˚C) released from ‘absorptio5 n
refrigeration’ to be utilized for desalination method. It comprises evaporation chamber,
a condenser, heat exchanger, thermal energy storage and different columns. The method
utilizes low grade thermal energy (approximate 55˚C) rejected by condenser in
Absorption Refrigeration System and stored in thermal energy storage tank. The stored
10 energy is then utilized in evaporation chamber to desalinate the saline water. The three
columns are used for saline water, brine and desaline water respectively. The system is
designed for manufacturing of the potable water and not for large scale industrial
purpose.
15 In the prior art document, US5346592 patent titled ‘Combine water purification and
power generation plant’ is provided thermal desalination using ‘Multistage Flashing
(MSF)’ system. The thermal energy is provided by two source i.e., enthalpy of steam
from bleeding of turbine and ‘superheated steam’ produce by steam heater. The system
produces distilled water, concentrated salt and power as well. Here the bleed steam and
20 superheated steam both are used as a major heat source for thermal desalination method
and both are produced from conventional fuel which otherwise could be used for some
extra power generation.
In the prior art document, EP2611735B1 titled ‘System and method for desalination of
25 sea water’ provides the combination of Flue gas desulphurization and thermal
desalination system for generation of desalinated water from sea water. The system uses
sea water from FGD system to desalination system. The major external heat source for
the method is taken from ‘power plant’ in the form of steam, however the exact source
is not clarified.
30
4
In the prior art document, WO 2013166882 discloses a system for desalination of
seawater by using waste heat from a power plant. The system comprises a condenser
circulation seawater intaking subsystem, a seawater multi-stage flash evaporation
subsystem and a subsystem for heating circulating seawater with boiler flue gas waste
heat, the subsystems being divided according to the flow direction of the seawater to b5 e
desalinated, and further comprises a vacuum pumping subsystem, and a fresh water and
seawater pollution discharging subsystem, wherein the vacuum pumping subsystem and
the fresh water and seawater pollution discharging subsystem are connected with the
seawater multi-stage flash evaporation subsystem as auxiliary systems. Thus, it forms
10 fresh water.
In the prior art document, CN 203112541 U is disclose a seawater desalter for the flue
gas waste heat recovery of the marine turbine, which is provided by the utility model,
firstly, flue gas generated by the marine turbine is utilized to heat seawater, so that the
15 seawater is boiled, and then two-stage heating of steam latent heat and quantitative
pollution discharging heat is performed on fresh seawater, so as to increase the
temperature of the fresh seawater which enters the steam generator, thereby improving
effective utilization of waste heat.
20 Thus, all these method have some sort of value operational limitation, complex control
intricacies or complex thermodynamic restrictions. The prior art methods either do not
form de-mineralized (DM) water or produce it in less quantity which may not be re-used
by the power plants. Also, the heat source is not one that conserves energy and water.
25 Hence, it is desirable to have a system and method that thermally desalinates sea water
by using waste heat of fossil fired power plant, which indirectly gives benefits in terms
of water conservation and waste heat recovery and also consequently reducing the cost
of preparation of demineralized water, fresh water and savings energy. Further, the
method and system has simplified controls, is thermodynamically compatible and poses
30 less operational risk to the existing regenerative steam cycle power plant.
5
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a
basic understanding of some aspects of the invention. This summary is not an extensive
overview of the present invention. It is not intended to identify the key/critical element5 s
of the invention or to delineate the scope of the invention. Its sole purpose is to present
some concept of the invention in a simplified form as a prelude to a more detailed
description of the invention presented later.
10 An object of the present invention is to provide a system and method for utilizing the
waste thermal energy of the fossil fired power plant for making distilled water, DM
water and potable water.
Another object of the present invention is to provide a system and method for utilizing
15 the waste heat of flue gases from fossil fired plant for producing hot water and then
steam to run thermal energy based desalination system.
Yet another object of the present invention to provide a system and method that
overcomes the dependencies over corporation’s supply of water for the power stations
20 situated in coastal areas where sea water is abundantly available.
Yet another object of the present invention is to provide a system and method that uses
waste heat of flue gases to run a thermal energy based desalination system to generate
make up water from sea water, demineralized water for feed water to boiler and potable
25 water for use in power stations.
Yet another object of the present invention is to provide a system and method that is
simple and cost effective.
30 Still another object of the present invention to provide a method that conserves energy
and water.
6
Accordingly, in one implementation, a system for preparation of desalinated water by
using waste heat from power plant is disclosed. The system comprises of three blocks.
The first block is a means to generate hot water to produce Low Pressure (LP) steam;
the second block having Multi Effect Distillation subsystem (MED) produce5 s
desalinated water from sea water; and a third block having electrodeionization (EDI)
subsystem for producing demineralized (DM) water. The first block comprises of a heat
exchanger to generate hot water and a flash chamber to produces low pressure steam
from the waste heat of the flue gas from the power plant.
10
In one implementation, a method for preparation of desalinated water by waste heat
from power plant is disclosed. The method comprises of : tapping the flue gas from
downstream of ID fan; using the tapped flue gas in heat exchanger to generate hot
water; recycling the remaining flue gas to the main dust; flashing the hot water in the
15 flash chamber to generate low pressure, low temperature steam; passing the low
pressure, low temperature steam through Multi Effect Distillation (MED) system to
initiate distillation and produce desalinated water; passing the condensed steam
produced to flue gas heat exchanger; polishing of desalinated water of step (vi) in the
electrodeionization system to produce demineralized water; wherein said waste heat of
20 flue gas from the power plant generates hot water and then low pressure steam.
As compared to the conventional techniques for preparation of desalinated water
available, if any, the present invention provides a steam generation provides utilizing
waste flue gas of power plant. The components that are disclosed in the present
25 invention (known and/or new) are custom designed and developed to achieve the steam
generation utilizing waste flue gas of power plant. For example, Multi Effect
Distillation (MED) in general is a known technology. In conventional MED process
steam of 4 to 8 bar is normally used. However in the present invention a steam
generated from waste flue gas coming out from power plant has steam pressure and
30 temperature are very low i.e. 0.34 ata / 72 degree C. A person skilled in the art will
understand that, normally at 72 degree C water will remain in water form only and not
7
inform of steam. Therefore the entire MED used in the present invention has been
custom designed so that it can operate successfully even with steam of 0.34 ata / 72 deg
C. Further, use of electrodeionization (EDI) to produce demineralized (DM) water,
using distillate from MED is totally a new process as the distillate temperature is high,
i.e., 46 to 48 degree C (around 48 Deg C)5 .
Also, as compared to the convention techniques, the present invention provides a new
the process for preparation of desalinated water by waste heat from power plant,
wherein, the present invention uses waste flue gas of power plant to produce LP steam,
10 the LP steam in MED operating at ultra-low steam parameter (0.34 ata / 72 Deg C) are
used to produce distillate, and further polishing distillate generated from MED to
produce DM water.
Other aspects, advantages, and salient features of the invention will become apparent to
15 those skilled in the art from the following detailed description, which, taken in
conjunction with the annexed drawings, discloses exemplary embodiments of the
invention.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
20
The above and other aspects, features, and advantages of certain exemplary
embodiments of the present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings in which:
25 Figure 1 illustrates in a Block diagram the ‘Flue Gas Waste Heat Recovery Based Sea
Water Desalination System for Fossil Fired Power Plant, in accordance with an
embodiment of the present subject matter.
Figure 2 illustrates the Block – A: LP steam Generation Block, in accordance with an
30 embodiment of the present subject matter.
8
Figure 3 illustrates the Block – B: Desalination Block, in accordance with an
embodiment of the present subject matter.
Figure 4 illustrates the Block – C: Desaline Water to DM water Conversion Block, in
accordance with an embodiment of the present subject matter5 .
Persons skilled in the art will appreciate that elements in the figures are illustrated for
simplicity and clarity and may have not been drawn to scale. For example, the
dimensions of some of the elements in the figure may be exaggerated relative to other
10 elements to help to improve understanding of various exemplary embodiments of the
present disclosure. Throughout the drawings, it should be noted that like reference
numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
15
The following description with reference to the accompanying drawings is provided to
assist in a comprehensive understanding of exemplary embodiments of the invention. It
includes various specific details to assist in that understanding but these are to be
regarded as merely exemplary.
20
Accordingly, those of ordinary skill in the art will recognize that various changes and
modifications of the embodiments described herein can be made without departing from
the scope of the invention. In addition, descriptions of well-known functions and
constructions are omitted for clarity and conciseness.
25
The terms and words used in the following description and claims are not limited to the
bibliographical meanings, but, are merely used by the inventor to enable a clear and
consistent understanding of the invention. Accordingly, it should be apparent to those
skilled in the art that the following description of exemplary embodiments of the present
30 invention are provided for illustration purpose only and not for the purpose of limiting
the invention as defined by the appended claims and their equivalents.
9
It is to be understood that the singular forms “a,” “an,” and “the” include plural
referents unless the context clearly dictates otherwise.
By the term “substantially” it is meant that the recited characteristic, parameter, or valu5 e
need not be achieved exactly, but that deviations or variations, including for example,
tolerances, measurement error, measurement accuracy limitations and other factors
known to those of skill in the art, may occur in amounts that do not preclude the effect
the characteristic was intended to provide.
10
Features that are described and/or illustrated with respect to one embodiment may be
used in the same way or in a similar way in one or more other embodiments and/or in
combination with or instead of the features of the other embodiments.
15 It should be emphasized that the term “comprises/comprising” when used in this
specification is taken to specify the presence of stated features, integers, steps or
components but does not preclude the presence or addition of one or more other
features, integers, steps, components or groups thereof.
20 In one implementation, the present invention provides a system and method for utilizing
the waste thermal energy of flue gases from the fossil fired plant for making distilled
water, DM water and potable water.
In one implementation, the present invention provides a system and method for utilizing
25 flue gases of fossil fired plant for producing hot water and then steam to run thermal
energy based desalination system to generate make up water, DM water, potable water
from sea water for the power stations.
In one implementation, the present invention provides a system and method that is
30 simple, cost effective and overcomes the dependencies over corporation’s supply of
10
water for the power stations situated in coastal areas where sea water is abundantly
available.
In one preferred implementation, the present invention provides a system and method
for desalination of water by waste heat from power plant is disclosed. The syste5 m
(Figure 1) comprises of three blocks. The three Blocks are: Block A – low pressure (LP)
steam Generator Block, Block B - Desalination Block and Block C – Distilled to
demineralised (DM) water conversion block. The first block is a means to generate hot
water to produce Low Pressure (LP) steam; the second block having multi effect
10 distillation system (MED) produces desalinated water from sea water; and a third block
having electrodeionization (EDI) system for producing DM water. The first block
comprises of a heat exchanger to generate hot water and a flash chamber to produces
low pressure steam from the waste heat of the flue gas from the power plant.
15 In one implementation, a separate close loop of DM water is provided, which is heated
with flue gas. This hot DM water is flashed to produce low pressure (LP) steam. This
steam is fed to MED as the energy source. Condensate from the steam goes back to
close loop DM water cycle.
20 In one implementation, the block A, LP steam generation block comprises of a set-up of
flue gas heat exchanger (11) and flash chamber (12).
In one implementation, the multi effect distillation (MED) subsystem may be a noncontact
type heat exchanger working under vacuum. MED in general is known
25 technology. In conventional MED process steam of 4 to 8 bar is normally used. In
present invention as steam is generated from waste flue gas coming out from power
plant. The steam pressure and temperature are very low i.e. 0.34 ata / 72 deg C.
Normally at 72 deg C water will remain in water form only and not inform of steam.
Therefore, entire MED subsystem of the present invention is designed so that it operates
30 successfully even with steam of 0.34 ata / 72 deg C.
11
In one implementation, the multi effect distillation (MED) subsystem is connected to
the condenser and a collector at the bottom side of MED where brine is collected which
is partially re-circulated to MED inlet and rest is rejected back to the sea. The distillate
i.e the desalinated water from the MED is at high temperature of 46 to 48 deg C, which
is passed though EDI to form DM water.5 .
In one implementation, the present invention provides a method for desalination of
water by waste heat from power plant is disclosed. The method comprises of:
• tapping the flue gas from downstream of ID fan;
10 • using the tapped flue gas of step (i) in heat exchanger to generate hot water;
• recycling the remaining flue gas to the main dust;
• flashing the hot water of step (ii) in the flash chamber to generate low pressure,
low temperature steam;
• passing the low pressure, low temperature steam of step (iv) through Multi
15 Effect Distillation(MED) system to initiate distillation and produce desalinated
water;
• passing the condensed steam produced in step (v) to flue gas heat exchanger;
• polishing of desalinated water of step (vi) in the electrodeionization system to
produce demineralized water.
20 • wherein said waste heat of flue gas from the power plant generates hot water and
then low pressure steam.
Referring now to figure 1 illustrates the block diagram of flue gas waste heat recovery
based sea water desalination system for fossil fired power plant, in accordance with an
25 embodiment of the present subject matter. The system (Figure 1) comprises of three
blocks. The three Blocks are: Block A – low pressure (LP) steam Generator Block,
Block B - Desalination Block and Block C – Distilled to demineralised (DM) water
conversion block. In one implementation, of the system and method for desalination of
water, a certain amount of flue gas is utilized to produce hot water which is then
30 transferred to the flash chamber operating on pressure below the atmosphere. Flash
chamber produces low pressure, low temperature steam which is then passed to the
12
MED subsystem. Here this steam acts as a motive steam to start the distillation method
and results in condensed steam which come back to flue gas heat exchanger. MED
subsystem is non-contact type heat exchanger which works under vacuum. The sea
water is sprayed from shell side which gets evaporated due to motive steam inside the
pipe. This evaporated steam is travelled to the all effect of MED subsystem an5 d
collected in condenser which is far end part of the MED. The brine is collected at the
bottom side of MED subsystem which is partially re-circulated to MED inlet and rest is
rejected back to the sea.
10 Referring now to figure 2, illustrates the block A: LP steam Generation Block system
comprises of a Flue Gas Heat Exchanger (FGHE) (11), flash chamber (12), ID fan (13),
Flue gas in and out (13, 14), DM make-up line with pump (17, 17a), hydrazine dosing
system (19) and the different piping and fittings including with controls and
instrumentations, in accordance with an embodiment of the present subject matter. In
15 one implementation, figure 2 schematically describes the method steps for generation of
hot water and steam. In the method, flue gas is tapped off from main duct after
electrostatic precipitator (ESP) before ID fan and then transferred to flue gas heat
exchanger (FGHE) 11 via guillotine gate G1 and small duct (14) and exit as a stream
(15) through guillotine gate G2. At the outlet side of flue gas an ID fan with VFD (13)
20 is installed for creating pressure drop across the FGHE. A flash chamber is initially
filled with DM water which is circulated through FGHE via cold DM water pump (17a)
and pipe (17) to the FGHE before taking flue gas inside the FGHE. The temperature of
the flue gas is in approximately in a range of 140-150 deg. C which transfers their heat
to cold DM water to generate hot DM water (18) at the temperature of approx. 90 deg.
25 C. A small hydrazine dosing subsystem (19) is also installed at the entry of DM water in
flash chamber to remove the remaining trace levels of dissolved oxygen. The level of
DM water can be judged by level transmitter (23) which gives appropriate signal to DM
water inlet solenoid valve (16 and 71, fig 4). The hot DM water (18) generated in FGHE
passes to flash chamber (12) which is operated below atmospheric pressure. The desired
30 vacuum is maintained vacuum pump (36, fig 3) via vacuum line (20). The generated
low pressure steam (21) is then passed to MED (31) through control valve (22).
13
Referring now to figure 3, illustrates the Desalination Block, comprises of Multi-Effect
Distillation (MED) 31, MED Condenser (32), flow meters (34,41,48, 50b), vacuum
pump (36), brine pump (39) with VFD, Sea Water Pump (50a), Distillate pump (46),
Control Valve (47,40), conductivity meter (50c, 33a, 38b, 49) and the various stream5 s
for different fluids, in accordance with an embodiment of the present subject matter. In
one implementation, figure 3 schematically describes the method steps for generation of
distilled water. In the method, sea water (50) is pumped in condenser (32) via sea by sea
water pump (50a). The reading of flow and conductivity of the sea water can be
10 measured by flow transmitter (50b) and (50c) respectively before entering the condenser
(32). At the outward of the condenser (32), sea water gets divide into two branches (51
and 35a). One stream of sea water (51) goes to the MED inlet (33) and other portion of
it (35a) gets back to the sea and this is controlled by motorized control valve (35). For
the operation of said control valve, signal is taken from flow meter (34) which is
15 installed at the saline water inlet line (33) of MED subsystem (31). The vacuum in
condenser (32) and MED (31) is maintained by vacuum pump (36) via vacuum line
(37). When low pressure steam (21) comes from flash chamber (12), the same time
saline water (33) also enters into MED (31). As mentioned earlier, MED (31) is noncontact
type heat exchanger which works under vacuum. The saline water (33) is
20 sprayed from shell side which gets evaporated due to motive steam (21) inside the pipe.
The evaporated sea water is then goes to second effect of MED (31) as a motive steam
and another evaporation method takes place. After completion of the number of effects
of evaporated steam (43) generated from saline water (33), it goes to condenser (32)
where it get condensed and collected as desaline water (45) via distilled water pump
25 (46) in to desaline water storage tank (60). The level of desaline water in condenser (32)
is determined by level transmitter (32a) at the bottom of condenser (32). Level
transmitter (32a) transmits the signal to the control valve (47) in desaline water line (45)
as and when required to maintain the level of desaline water in the condenser (32a).
Another stream come out from MED (31) is brine (38) which is basically saline water
30 with higher percentage of salts compare with saline water (33) at inlet of MED (31).
The brine is again recirculated partially to MED (31) by controlling it flow through
14
control valve (40). The operating signal for control valve (40) comes from conductivity
meter (38a). The rejected brine (40a) goes back to sea. Hence saline water flow (33) at
the inlet of MED (31) is basically combination of the recirculated brine (42) and sea
water (51) out from condenser (32). The brine level inside the MED (31) is maintained
by controlling brine pimp (39) with VFD. Level transmitter is installed at bottom side o5 f
MED (31) to give signal to brine pump (39). Another stream i.e. desalinated water (44)
collected at the bottom side of MED (31) is transferred to the condenser and collectively
pumped to desaline water tank (60). Desaline water line is equipped with conductivity
meter (49) and flow transmitter (48).
10
Referring now to figure 4 illustrates the Desaline Water To DM water Conversion
Block comprises of Distillate (desaline water) Tank (60), distilled Water Pump (62a),
Electrodeionization System (62), DM water pump (66), Drinking Water Tank (64)
Control Valve (71), Solenoid Valve (71), Conductivity meter(65a), pH meter(65b),
15 Silica Meter (65c) and the different piping and fittings including with controls and
instrumentations, in accordance with an embodiment of the present subject matter. In
one implementation, figure 4 schematically describes the method steps for generation of
De-mineralized (DM) water from Desaline water. In the method, desaline water 60a is
transferred from desaline water tank (60) to Electrodeionization (EDI) system (62) by
20 pump (62a).
EDI is a method which combines semi-impermeable membrane technology with ionexchange
media to provide a purest form of water i.e., DM water. It removes residual
salts and ionizable aqueous species - like carbon dioxide, silica, ammonia and boron etc.
25 from the water.
In one implementation, the system forms two streams of DM water from saline water
(60a), EDI (62). The streams goes to i.e., (i) drinking water (63) goes to drinking water
tank (64) and (ii) DM water (68) is pumped (66) to DM water storage tank.
30
15
In one implementation, the quality of DM water (65) before going DM water storage
tank is checked by conductivity meter (65a), pH meter (65b) and silica Meter (65c)
respectively.
In one implementation, at least one solenoid valve (69) is installed on DM rejection lin5 e
(70) which operates by taking signal from conductivity meter (65a).
In one implementation, at least one solenoid valve (71) is installed in DM water makeup
line (72) for flash chamber (12).
10
The present system and method is ideal for multiple applications including feed water
for boiler for power generation, demineralized water and potable water.
It may be understood by the person skilled in that art that, the method such as
15 desalination, distillation, evaporation and the like method may be achieved by the
existing mechanism/components/elements which may not be considered as the essential
part of the present invention, and hence is not explained in detail about the same in the
present invention.
20 It may be understood by the person skilled in that art that, the order in which the method
is described is not intended to be construed as a limitation, and any number of the
described method blocks/subsystem can be combined in any order to implement the
method or alternate methods. Additionally, individual blocks/subsystem may be deleted
from the method without departing from the scope of the subject matter described
25 herein. Furthermore, the method can be implemented in any suitable hardware,
software, firmware, or combination thereof.
Although a method for preparation of demineralized water from desalinated water by
use of waste heat of flue gas from power plant have been described in language specific
30 to structural features and/or method, it is to be understood that the embodiments
disclosed in the above section are not necessarily limited to the specific features or
16
method or systems described. Rather, the specific features are disclosed as examples of
implementations of the method for preparation of demineralized water from desalinated
water by use of waste heat of flue gas from power plant.
17

WE CLAIM:
1. A system for the desalination of sea water by utilizing a waste heat (flue gas) of
the power plant to obtain the de-mineralized (DM) water, the system comprising5 :
at least one low pressure (LP) steam generation block adapted to receive the
waste heat, and generate hot water by passing the waste heat and flash the hot DM water
to thereby obtain a low pressure (LP) steam;
at least one multi effect distillation (MED) block adapted to receive the low
10 pressure and temperature(LP) steam, and generate the desalined water by passing the
low pressure (LP) steam received through the spread saline water; transferring thermal
energy on LP steam to the sprinkle sea water in order to produce water vapor, which is
condensed to obtained distillate.
at least one water conversion block adapted to receive the desalined water
15 generated, and generate the de-mineralized (DM) water using an Electrodeionization
(EDI) mechanism.
2. The system as claimed in claim 1, wherein the low pressure (LP) steam
generation block comprises:
20 at least one flue gas heat exchanger integrated in a flue gas duct before the
chimney of the power plant, and adapted to:
tap out the waste heat, generate the hot water by passing the waste heat
tapped out through the water received from at least one flash chamber,
and communicate the hot water generated to the flash chamber; and
25 the flash chamber comprises at least one vacuum pump maintain a desired
vacuum, on receipt of the hot water, to generate the low pressure (LP) steam.
3. The system as claimed in claim 1, wherein the multi effect distillation (MED)
block comprises:
18
at least one condenser adapted to receive the saline water from at least one
pump, and adapted to communicate the saline water to the multi effect distillation
(MED) as input; and
the multi effect distillation (MED) block, on receipt of the low pressure (LP)
steam and the saline water, generate the evaporated steam of the saline water, an5 d
thereby communicate the evaporated steam to the condenser, wherein the condenser is
adapted to condense the evaporated steam to obtain the desalined water and preferably,
stored in at least one desalined storage tank.
10 4. The system as claimed in claim 3, wherein the multi effect distillation (MED)
block comprises a brine line carrying the saline water with higher percentage of salts,
after the desalined water is obtained, and adapted to recirculate the saline water from
the brine line to the multi effect distillation (MED) block.
15 5. The system as claimed in claim 4, wherein the saline water recirculated from the
brine line is maintained at a particular level and is controlled using at least one brine
pump.
6. The system as claimed in claim 1, wherein the water conversion block comprises
20 the Electrodeionization (EDI) mechanism adapted to receive the desalined water prestored
in at least one the desaline tank, the desaline tank receives the desaline water
from the multi effect distillation (MED) block.
7. A method for the desalination of sea water by utilizing a waste heat (flue gas) of
25 the power plant to obtain the de-mineralized (DM) water, the method comprising:
(i) tapping the flue gas from downstream of ID fan;(ii) using the tapped flue gas of step (i) in heat exchanger (FGHE) to generate
hot water;
(iii) recycling the remaining flue gas to the main duct;30 (iv) flashing the hot water of step (ii) in the flash chamber to generate low
pressure steam;
19(v) passing the low pressure, low temperature steam of step (iv) through Multi
Effect Distillation(MED) subsystem to initiate distillation and produce desalinated
water;(vi) passing the condensed steam produced in step (v) to flue gas heat
exchanger5 ; polishing of desalinated water of step (vi) in the electrodeionization system to
produce demineralized water;
wherein said waste heat of flue gas from the power plant generates hot water and then
low pressure steam.