DESC:FIELD
The present disclosure relates to the field of chemical engineering. Particularly, the present disclosure relates to a system and a method for online determination of the concentration of dissolved carbon dioxide in a liquid sample.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Masking effect refers to the concentration of ions.
Online determination refers to the determination of the dissolved carbon dioxide in a liquid sample by allowing the liquid sample to pass through a system.
BACKGROUND
A magnetite (Fe3O4) layer is commonly used as a coating material in boilers, for example - steam boilers, due to its stability at high temperatures. Particularly, during the working of the boilers, scaled layer of residuals such as silica, iron, carbonate, and the like may be formed on the magnetite layer due to foaming. This scaled layer reduces the rate of heat transfer between fluids, for example – steam and water, introduced into the boilers, thereby affecting the efficiency thereof. Therefore, there is a need to remove the scaled layer from the boilers.
This is generally done by dosing the boilers with a desired concentration of tri-sodium phosphate (Na3PO4), thereby increasing the pH therein in the range of 8.2 to 9.2. At this alkaline pH range, the steam boilers contain hydroxide (OH-), bicarbonate (HCO3-), and carbonate (CO3-) ions. These ions act as acid absorbing constituents.
At a pH above 8.3, the bicarbonate (HCO3-) ion is converted to the carbonate ion (CO3-).
HCO3-? H+ + CO32- (carbonate ion)
Moreover, traces of dissolved carbon dioxide (CO2) are formed due to the dosing of tri-sodium phosphate in the boilers. CO2 when dissolved in a sample or heat transfer fluid, for example – water, facilitates corrosion of piping systems, mounting systems, and other accessories of the steam boilers, thereby affecting the overall performance or efficiency of the boilers. Reactions illustrating the formation of carbonic acid and bicarbonate ions are depicted herein below.
CO2 (dissolved) + H2O ? H2CO3 (carbonic acid)
H2CO3 (carbonic acid) ? H+ + HCO3- (bicarbonate ion)
Therefore, there is a need for an alternative to determine the concentration of dissolved CO2 in a sample, particularly water that obviates the above mentioned drawbacks or problems associated with the boilers.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to determine the concentration of dissolved CO2 in a liquid sample.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a system for online determination of the concentration of dissolved carbon dioxide in a liquid sample. The system comprises a sample holder, a conductivity determining unit, a cation conductivity determining unit, a re-boiler, a purge valve, a waste heat recovery unit, and a degassed conductivity determining unit.
The conductivity determining unit comprises a conductivity flow through chamber and a specific conductivity cell. The cation conductivity determining unit comprises a cation resin column and a cation conductivity cell. The degassed conductivity determining unit comprises a degassed conductivity flow through chamber and a degassed conductivity cell.
The sample holder can be adapted to receive the liquid sample with dissolved carbon dioxide therein.
The conductivity flow through chamber can be adapted to receive the liquid sample from the sample holder and store the liquid sample in the conductivity determining unit.
The specific conductivity cell can be adapted to determine a specific conductivity of the liquid sample contained in the conductivity flow through chamber.
The cation resin column can be adapted to receive the liquid sample from the specific conductivity flow through chamber and remove cations comprising ammonium (NH4+) and H+ ions contained in the liquid sample, thereby facilitating reduction in the determined specific conductivity of the liquid sample by the specific conductivity cell and eliminating the masking effect of NH4+.
The cation conductivity cell can be adapted to determine the reduced specific conductivity of the liquid sample contained in the cation resin column.
The re-boiler can be adapted to receive the liquid sample from the cation resin column and heat the liquid sample at a pre-determined temperature in the range of 97°C to 100°C to form a heated sample comprising a portion of gas including carbon dioxide and a portion of degassed liquid including at least one anion selected from the group consisting of OH-, Cl-, SO4-, PO4-, NO3-, and HCO3-.
The purge valve can be adapted to receive at least a portion of the heated sample from the re-boiler and separate the portion of gas including carbon dioxide and the portion of degassed liquid from the heated sample.
The waste heat recovery unit can be adapted to receive a remaining portion of the heated sample at 97°C to 100°C from the re-boiler and dissipate heat to an incoming sample at ambient temperature for pre-heating the incoming sample, thereby reducing the electrical consumption. The degassed conductivity flow through chamber can be adapted to receive and store the portion of cooled degassed liquid from the waste heat recovery unit.
The degassed conductivity cell can be adapted to determine a conductivity of the portion of degassed liquid and the concentration of dissolved carbon dioxide in the portion of degassed liquid contained in the degassed conductivity flow through chamber.
The system can further comprise a rotameter.
The rotameter can be adapted to maintain the flow-rate of the sample in the cation conductivity determining unit and the degassed conductivity determining unit.
The system can further comprise a valve, wherein the valve can be adapted to control the flow of sample received in the sample holder.
The system can further comprise a first transmitter and a second transmitter, wherein the first transmitter and the second transmitter can be adapted to display the determined specific conductivity and the determined cation conductivity of the liquid sample respectively.
The re-boiler can comprise a plurality of heaters.
The present disclosure also relates to a method for online determination of the concentration of dissolved carbon dioxide in the liquid sample using the system as described herein above. The method comprises introducing the liquid sample with dissolved carbon dioxide is introduced in the sample holder. The liquid sample is received in the conductivity determining unit from the sample holder for determining a specific conductivity of the liquid sample. From the conductivity determining unit, the liquid sample is introduced into the cation conductivity determining unit for removing cations comprising ammonium (NH4+) and H+ ions contained in the liquid sample, thereby facilitating reduction in the determined specific conductivity of the liquid sample, eliminating the masking effect of NH4+, and determining a reduced specific conductivity of the liquid sample. From the cation conductivity determining unit, the sample is received in the re-boiler for heating the liquid sample at a pre-determined temperature in the range of 97°C to 100°C to form a heated sample comprising a portion of gas including carbon dioxide and a portion of degassed liquid including at least one anion selected from the group consisting of OH-, Cl-, SO4-, PO4-, NO3-, and HCO3-. A portion of the heated sample is allowed to pass through the purge valve from the re-boiler for separating the portion of gas including carbon dioxide and the portion of degassed liquid from the heated sample. A remaining portion of the heated sample at 97°C to 100°C is introduced into the waste heat recovery unit for dissipating heat to the incoming sample at ambient temperature for pre-heating incoming sample to the re-boiler. Further, the portion of liquid is received in the degassed conductivity determining unit from the purge valve for determining a degassed conductivity of the portion of degassed liquid and the concentration of dissolved carbon dioxide in the portion of degassed liquid.
The liquid sample can be water.
The concentration of dissolved carbon dioxide in the portion of degassed liquid can be determined by deducting the conductivity of pure water from the conductivity of the portion of degassed liquid to obtain an intermediate conductivity value and further deducting the intermediate conductivity value from the reduced specific conductivity (cation conductivity) of the liquid sample to obtain a final conductivity value, wherein the final conductivity value corresponds to the concentration of dissolved carbon dioxide in the portion of degassed liquid.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a schematic view of a system for online for online determination of the concentration of dissolved carbon dioxide in a liquid sample in accordance with the present disclosure;
Figure 2 illustrates a flow chart in accordance with the present disclosure;
Figure 3 illustrates a flow chart in accordance with the present disclosure;
Figure 4 illustrates a schematic view of a purge valve in accordance with the present disclosure;
Figure 5 illustrates a graph depicting variations in cation conductivity and degassed conductivity of a liquid sample in accordance with the present disclosure; and
Figure 6 illustrates a graph depicting variations in the concentration of dissolved carbon dioxide in a liquid sample with and without dosing concentrations in accordance with the present disclosure.
List of reference numerals
System - (100); Mounting plate - (101); Sample holder - (102); Valve - (103); Conductivity flow through chamber - (104a); Degassed conductivity flow through chamber - (104b); Specific conductivity cell - (105); Cation resin column - (106); Cation conductivity cell - (107); First transmitter - (108); Rotameter - (109); Waste heat recovery unit - (110); Re-boiler - (111); Plurality of heaters - (112); Temperature control system (113); Purge valve - (114); Degassed conductivity cell - (115); Second transmitter - (116); Monitor - (117); Conductivity determining unit - (C); Cation conductivity (Cc); Degassed conductivity determining unit - (Dc); Purge valve – (400); Sample inlet port - (401); Inlet/outlet tube connectors - (402); Sample outlet port - (403); Purge valve body - (404); Gas exhaust port - (405); Gas exhaust tube connector - (406); Guide tube - (407); Float - (408); Sealing ball - (409); Actuating pin - (410); Lock nut - (411); Float lock pin - (412); Valve cavity - (413); Cut-out - (414); Portion - (A); and Portion (B).
DETAILED DESCRIPTION
As described herein above, traces of dissolved carbon dioxide (CO2) in a liquid sample or heat transfer fluid, for example – water, formed due to the dosing of tri-sodium phosphate in the boilers, results in corroding piping systems, mounting systems, and other accessories of the boilers, thereby affecting the overall performance or efficiency of the boilers.
The present disclosure, therefore, envisages a system and a method for online determination of the concentration of dissolved carbon dioxide in the liquid sample so as to obviate the above mentioned drawbacks. The system is described hereinafter with reference to Figure 1.
The system (100) comprises:
a) a sample holder (102), wherein the sample holder (102) is adapted to receive the liquid sample with dissolved carbon dioxide therein;
b) a conductivity determining unit (C), wherein the conductivity determining unit (C) comprises:
o a conductivity flow through chamber (104a) that is adapted to receive the liquid sample from the sample holder (102) and store the liquid sample in the conductivity determining unit (104); and
o a specific conductivity cell (105) that is adapted to determine a specific conductivity of the liquid sample contained in the conductivity flow through chamber (104);
c) a cation conductivity determining unit (Cc), wherein the cation conductivity determining unit (Cc) comprises:
o a cation resin column (106) that is adapted to:
? receive the liquid sample from the conductivity flow through chamber (104); and
? remove cations comprising ammonium (NH4+) and H+ ions contained in the liquid sample, thereby facilitating reduction in the determined specific conductivity of the liquid sample by the specific conductivity cell (105) and eliminating the masking effect of NH4+; and
o a cation conductivity cell (107) that is adapted to determine the reduced specific conductivity or a cation conductivity of the liquid sample contained in the cation resin column (106);
d) a re-boiler (111) that is adapted to:
? receive the liquid sample from the cation resin column (106); and
? heat the liquid sample at a pre-determined temperature in the range of 97°C to 100°C to form a heated sample comprising a portion of gas including carbon dioxide and a portion of degassed liquid including at least one anion selected from the group consisting of Cl-, SO4-, PO4-, NO3-, and HCO3-.
e) a purge valve (114) that is adapted to:
? receive at least a portion of the heated sample from the re-boiler (111); and
? separate the portion of gas including carbon dioxide and the portion of degassed liquid from the heated sample;
f) a waste heat recovery unit (110) that is adapted to:
? receive a remaining portion of said heated sample from said re-boiler (111);
? re-circulate the remaining portion of said heated sample to and from said re-boiler (111) for pre-heating the sample; and
? dissipating heat to an incoming sample at ambient temperature for pre-heating said incoming sample in said re-boiler (111), thereby reducing the electrical consumption of said re-boiler (111); and
g) a degassed conductivity determining unit (Dc), wherein the degassed conductivity determining unit (Dc) comprises:
o a degassed conductivity flow through chamber (104b) that is adapted to receive and store the portion of degassed liquid from the waste heat recovery unit (110); and
o a degassed conductivity cell (115) that is adapted to determine a conductivity of the portion of degassed liquid and the concentration of dissolved carbon dioxide in the portion of degassed liquid contained in the degassed conductivity flow through chamber (104b).
The system (100) further comprises a valve (103), wherein the valve (103) can be adapted to control the flow of the liquid sample received in the sample holder (102).
In accordance with one embodiment of the present disclosure, the valve (103) can be a needle valve.
The system (100) further comprises a rotameter (109), wherein the rotameter (109) can be adapted to maintain the flow-rate of the liquid sample in the cation conductivity determining unit (Cc) and the degassed conductivity determining unit (Dc).
The system (100) further comprises a first transmitter (108) and a second transmitter (116), wherein the first transmitter (108) can be adapted to display the determined specific conductivity and the determined cation conductivity of the liquid sample and the second transmitter (116) can be adapted to display the conductivity of the portion of degassed liquid.
The re-boiler (111) comprises a plurality of heaters (112), wherein the plurality of heaters (112) can be adapted to heat the liquid sample at a pre-determined temperature.
In accordance with one embodiment of the present disclosure, the pre-determined temperature can be a boiling temperature of the liquid sample.
The system (100) further comprises a temperature control system (113), wherein the temperature control system can be adapted to control the pre-determined temperature of the liquid sample in the range of plus - minus 0.5°C.
The system (100) further comprises a monitor (117). The monitor (117) can be adapted to display the diagnosis of the specific conductivity of the liquid sample, the cation conductivity of the liquid sample, and the conductivity of the portion of degassed liquid.
In one embodiment of the present disclosure, the system (100) can be mounted on a mounting plate (101).
In accordance with the present disclosure, the purge valve is described with reference to Figure 4. In the Figure 4, for the purpose of illustration, the purge valve (114) is referred with numeral (400). The purge valve (400) comprises a purge valve body (404) including a sample inlet port (401), a sample outlet port (403), and a gas exhaust port (405). The sample inlet port (401) and the sample outlet port (403) are fitted with inlet/outlet tube connectors (402). The purge valve (400) further includes a valve cavity (413).
The gas exhaust port (405) is fitted with a specially machined gas exhaust tube connector (406). The gas exhaust tube connector (406) houses a sealing ball (409) and an actuating pin (410). The sealing ball (409) and the actuating pin (410) are held in position by a lock nut (411). The actuating pin (410) is free floating and reciprocates up-and-down based on the upward push from a float (408) and gravitational force, respectively. The sealing ball (409) can be welded to the actuating pin (410). The lock nut (411) can be provided with additional holes so as to obviate the restriction of the flow of exhaust gases.
The purge valve (400) further includes a guide tube (407) attached to the gas exhaust tube connector (406). The guide tube (407) is provided with a float lock pin (412) towards its operative bottom portion. The float (408) slides inside the guide tube (407) and is restricted by the float lock pin (412) from completely sliding out of the operative bottom portion. The guide tube (407) is provided with a cut-out (414) to ensure that the water level inside and outside the guide tube (407) is the same.
Particularly, the heated sample comprising the portion of gas and the portion of degassed liquid enters the purge valve (400) via the sample inlet port (401), thereby separating the portion of the degassed liquid and the portion of gas in the valve cavity (413). The portion of gas exits via the gas exhaust port (405), while the degassed liquid exits via the sample outlet port (403). The guide tube (407) ensures that the incoming sample (heated sample) does not directly impinge on the float (408), thereby facilitating convenient up-and-down movement of the float (408) conveniently.
More particularly, due to the inlet of the heated sample in the purge valve (400), the water level in the valve cavity (413) is increased, thereby lifting up the float (408) due to buoyancy, i.e., the heated sample is introduced into the purge valve (400) until the water level inside the valve cavity (413) is increased, thereby resulting in closing of the purge valve (400).
Due to this, the actuating pin (410) and consequently the sealing ball (409) are pushed upwards against the self-weight (gravity) and/or a spring force, thereby obviating the flow of the portion of gas from the gas exhaust port (405). This condition describes the “closed position” of the purge valve (400).
After a certain period, the portion of gas is separated from the heated sample in the valve cavity (413) and is accumulated at an operative top portion in the valve cavity (413). As a result, the level of the portion of degassed liquid inside the valve cavity (413) is decreased, thereby facilitating the float (408) to move in a downward direction. The actuating pin (410) and the sealing ball (409) move downwards under the gravity and/or by the spring force, and thus, the accumulated gas exits from the gas exhaust port (405). This condition describes the “open position” of the purge valve (400).
The purge valve (400) facilitates:
• separation of the portion of gas and the portion of degassed liquid from the heated sample; and
• periodic discharge of the portion of gas from the gas exhaust port (405) due to alternative decrease and increase of the level of the portion of degassed liquid in the valve cavity (413).
The method of the present disclosure is described with reference to Figure1 and Figure 2.
In the first step, the liquid sample with dissolved carbon dioxide is introduced in the sample holder (102).
In the second step, the liquid sample is received in the conductivity determining unit (C) from the sample holder (102) for determining the specific conductivity of the liquid sample.
In the third step, the liquid sample is introduced into the cation conductivity determining unit (Cc) from the conductivity determining unit (C) for removing cations comprising ammonium (NH4+) and H+ ions contained in the liquid sample, thereby facilitating reduction in the determined specific conductivity of the liquid sample, eliminating the masking effect of NH4+, and determining the reduced specific conductivity or the cation conductivity of the liquid sample.
In accordance with the present disclosure, when the value of the cation conductivity of the liquid sample determined in the conductivity determining unit (C) rises and approaches the value of the specific conductivity of the liquid sample determined in the conductivity determining unit (C), it is necessary to refill the cation resin column (106), thereby facilitating in determining an appropriate concentration of the dissolved CO2.
In accordance with one embodiment of the present disclosure, the liquid sample introduced into the cation conductivity determining unit (Cc) comprises H+, Na+, NH4+, OH-, Cl-, SO4-, PO4-, and NO3-, and HCO3-. The liquid sample leaving the cation conductivity determining unit (Cc) comprises OH-, Cl-, SO4-, PO4-, NO3-, HCO3-, and CO2 (as shown in Figure 3).
In the third step, the liquid sample is received in the re-boiler (111) from said cation conductivity determining unit (Cc) for heating the liquid sample at a pre-determined temperature in the range of 97°C to 100°C to form the heated sample comprising the portion of gas including carbon dioxide and the portion of degassed liquid including at least one anion selected from the group consisting of OH-, Cl-, SO4-, PO4-, NO3-, and HCO3-.
In accordance with one embodiment of the present disclosure, the liquid sample introduced into the re-boiler (111) comprises OH-, Cl-, SO4-, PO4-, and NO3-, and HCO3-, and CO2 (as shown in Figure 3).
In the fourth step, the portion of the heated sample is allowed to pass through the purge valve (114) from the re-boiler (111) for separating the portion of gas including carbon dioxide and the portion of degassed liquid from the heated sample (as shown in Figure 3).
In the fifth step, the remaining portion of the heated sample is introduced into the waste heat recovery unit (110) for dissipating heat to the incoming sample at ambient temperature to pre-heat the incoming fresh sample in the re-boiler (111), thereby reducing electricity consumption required for online determination of the dissolved carbon dioxide in the sample.
In the fifth step, the portion of degassed liquid is received in the degassed conductivity determining unit (Dc) from the purge valve (114) and waste heat recovery unit (110) for determining the conductivity of the portion of degassed liquid and the concentration of dissolved carbon dioxide in the portion of degassed liquid.
Particularly, the concentration of dissolved carbon dioxide in the portion of degassed liquid can be determined by the following steps.
In the first step, the conductivity of pure water (typically the conductivity of pure water is 0.055 µS/cm) can be deducted from the conductivity of the portion of degassed liquid to obtain an intermediate conductivity value.
In the second step, the intermediate conductivity value can be further deducted from the reduced specific conductivity/ cation conductivity of the liquid sample to obtain a final conductivity value, wherein the final conductivity value corresponds to the concentration of dissolved carbon dioxide in the portion of degassed liquid.
By determining the concentration of dissolved carbon dioxide, dosing of tri-sodium phosphate (Na3PO4) in the boilers can be controlled accordingly so as to obviate the above mentioned drawbacks. This effect can be illustrated with graphs depicted in Figures 5 and 6.
In the Figure 5, a portion (A) depicts “no control action” and a portion (B) depicts “control action”, i.e., by controlling the dosing of tri-sodium phosphate (Na3PO4) and maintaining sufficient OH– ions or P-alkali and M-alkali in the boilers. Particularly, without controlling the dosing of tri-sodium phosphate (Na3PO4), the value of cation conductivity and the value of the conductivity of the degassed liquid respectively is increased (as represented by curve 1), and with controlled dosing of the tri-sodium phosphate (Na3PO4), the value of cation conductivity and the value of the conductivity of the degassed liquid respectively is decreased (as represented by curve 2). The decreased values of the conductivities indicate that the concentration of dissolved carbon dioxide in the degassed liquid is decreased.
In the Figure 6, a portion (A) depicts “no control action” and a portion (B) depicts “control action”, i.e., by controlling the dosing of tri-sodium phosphate (Na3PO4) in the boilers. Particularly, without controlling the dosing of tri-sodium phosphate (Na3PO4), the concentration of dissolved carbon dioxide in the degassed liquid is increased (as represented by curve 1), and with controlled dosing of the tri-sodium phosphate (Na3PO4) the concentration of dissolved carbon dioxide in the degassed liquid is decreased (as represented by curve 2).
The system and the method of the present disclosure also facilitates in determining pH of the sample, depending upon the conductivity values.
TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a system and a method that:
- facilitates in online determination of the concentration of dissolved carbon dioxide in a liquid sample effectively; and
- facilitates in online determination of the pH of a liquid sample effectively.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:1. A system (100) for online determination of the concentration of dissolved carbon dioxide in a liquid sample, said system comprising:
h) a sample holder (102) adapted to receive said liquid sample with dissolved carbon dioxide therein;
i) a conductivity determining unit (C) including:
o a conductivity flow through chamber (104a) adapted to receive said liquid sample from said sample holder (102) and store said liquid sample therein; and
o a specific conductivity cell (105) adapted to determine a specific conductivity of said liquid sample contained in said conductivity flow through chamber (104a);
j) a cation conductivity (Cc) determining unit including:
o a cation resin column (106) adapted to:
? receive said liquid sample from said conductivity flow through chamber (104a); and
? remove cations comprising ammonium (NH4+) and H+ ions contained in said liquid sample, thereby facilitating reduction in the determined specific conductivity of said liquid sample by said specific conductivity cell and eliminating the masking effect of NH4+; and
o a cation conductivity cell (107) adapted to determine the reduced specific conductivity / cation conductivity of said liquid sample contained in said cation resin column (106);
k) a re-boiler (111) adapted to:
? receive said liquid sample from said cation resin column (106); and
? heat said liquid sample at a pre-determined temperature in the range of 97°C to 100°C to form a heated sample comprising a portion of gas including carbon dioxide and a portion of degassed liquid including at least one anion selected from the group consisting of OH-, Cl-, SO4-, PO4-, NO3-, and HCO3-.
l) a purge valve (114) adapted to:
? receive at least a portion of said heated sample from said re-boiler (111); and
? separate said portion of gas including carbon dioxide and said portion of degassed liquid from said heated sample;
m) a waste heat recovery unit (110) adapted to:
? receive a remaining portion of said heated sample from said re-boiler (111);
? re-circulate said remaining portion of said heated sample to and from said re-boiler (111) for pre-heating said sample; and
? dissipating heat to an incoming sample at ambient temperature for pre-heating said incoming sample in said re-boiler (111), thereby reducing the electrical consumption of said re-boiler (111);
n) a degassed conductivity determining unit (Dc) including:
o a degassed conductivity flow through chamber (104b) adapted to receive and store said portion of degassed liquid from said purge valve (114); and
o a degassed conductivity cell (115) adapted to determine a conductivity of said portion of degassed liquid and the concentration of dissolved carbon dioxide in said portion of degassed liquid contained in said degassed conductivity flow through chamber (104b).

2. The system as claimed in claim 1, further comprises a rotameter (109), wherein said rotameter (109) is adapted to maintain the flow-rate of said liquid sample in said cation conductivity determining unit (Cc) and said degassed conductivity determining unit (Dc).

3. The system as claimed in claim 1, further comprises a valve (103), wherein said valve (103) is adapted to control the flow of said liquid sample received in said sample holder (102).

4. The system as claimed in claim 1, further comprises a first transmitter (108) and a second transmitter (116), wherein said first transmitter (108) is adapted to display the determined specific conductivity and the determined cation conductivity of said liquid sample and said second transmitter (116) is adapted to display the conductivity of said portion of degassed liquid.

5. The system as claimed in claim 1, wherein said re-boiler (111) comprises a plurality of heaters (112).

6. The system as claimed in claim 1, wherein the electrical consumption of said re-boiler (111) is reduced by 60% to 70%.

7. A method for online determination of the concentration of dissolved carbon dioxide in said liquid sample using said system (100) as claimed in any one of the claims 1 to 6, said method comprising the following steps:
a) introducing said liquid sample with dissolved carbon dioxide in said sample holder (102);
b) receiving said liquid sample in said conductivity determining unit (C) from said sample holder (102) for determining a specific conductivity of said liquid sample;
c) introducing said liquid sample into said cation conductivity determining unit (Cc) from said conductivity determining unit (C) for removing cations comprising ammonium (NH4+) and H+ ions contained in said liquid sample, thereby facilitating reduction in the determined specific conductivity of said liquid sample, eliminating the masking effect of NH4+, and determining a reduced specific conductivity / cation conductivity of said liquid sample;
d) receiving said liquid sample in said re-boiler (111) from said cation conductivity determining unit (Cc) for heating said liquid sample at a pre-determined temperature in the range of 97°C to 100°C to form a heated sample comprising a portion of gas including carbon dioxide and a portion of degassed liquid including at least one anion selected from the group consisting of OH-, Cl-, SO4-, PO4-, NO3-, and HCO3-;
e) allowing a portion of said heated sample to pass through said purge valve (114) from said re-boiler (111) for separating said portion of gas including carbon dioxide and said portion of degassed liquid from said heated sample;
f) introducing a remaining portion of said heated sample into said waste heat recovery unit (110) for re-circulating said remaining portion of said heated sample to and from said re-boiler (111) for pre-heating said sample; and
g) receiving said portion of degassed liquid in said degassed conductivity determining unit (Dc) from said purge valve (114) for determining a conductivity of said portion of degassed liquid and the concentration of dissolved carbon dioxide in said portion of degassed liquid.

8. The method as claimed in claim 7, wherein said liquid sample is water.

9. The method as claimed in claim 7 or claim 8, wherein the concentration of dissolved carbon dioxide in said portion of degassed liquid is determined by:
• deducting the conductivity of pure water from said conductivity of said portion of degassed liquid to obtain an intermediate conductivity value; and
• further deducting said intermediate conductivity value from said reduced specific conductivity of said liquid sample to obtain a final conductivity value, wherein said final conductivity value corresponds to the concentration of dissolved carbon dioxide in said portion of degassed liquid.