CN117368270A - Method and device for measuring total organic carbon ion value in high-pressure boiler feed water - Google Patents
Method and device for measuring total organic carbon ion value in high-pressure boiler feed water Download PDFInfo
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 240
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 30
- 150000001768 cations Chemical class 0.000 claims abstract description 70
- 230000003647 oxidation Effects 0.000 claims abstract description 36
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 36
- -1 carbon ion Chemical class 0.000 claims abstract description 35
- 238000007872 degassing Methods 0.000 claims abstract description 26
- 230000001590 oxidative effect Effects 0.000 claims abstract description 10
- 239000007788 liquid Substances 0.000 claims description 26
- 238000010521 absorption reaction Methods 0.000 claims description 25
- 230000002572 peristaltic effect Effects 0.000 claims description 19
- 239000012528 membrane Substances 0.000 claims description 14
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 8
- 150000001449 anionic compounds Chemical class 0.000 claims description 7
- 229910001412 inorganic anion Inorganic materials 0.000 claims description 7
- 239000005416 organic matter Substances 0.000 claims description 6
- 230000003287 optical effect Effects 0.000 claims description 2
- 230000001172 regenerating effect Effects 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 238000001514 detection method Methods 0.000 abstract description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 20
- 238000005259 measurement Methods 0.000 description 13
- 229910021529 ammonia Inorganic materials 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 7
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 5
- 239000010453 quartz Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 230000002378 acidificating effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004255 ion exchange chromatography Methods 0.000 description 3
- 150000001450 anions Chemical class 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 125000005842 heteroatom Chemical group 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
- G01N27/07—Construction of measuring vessels; Electrodes therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
- G01N27/08—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid which is flowing continuously
- G01N27/10—Investigation or analysis specially adapted for controlling or monitoring operations or for signalling
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Abstract
The invention relates to the technical field of detection instruments, and discloses a method and a device for measuring total organic carbon ion values in high-pressure boiler feed water. The method comprises the following steps: removing cations from a water sample containing organic carbon ions to obtain a cation-removed water sample, and removing CO from the cation-removed water sample 2 Obtaining a water sample to be detected, and measuring the conductivity of the water sample to be detected to obtain a first conductivity; oxidizing the water sample to be detected to obtain an oxidized water sample, and measuring the conductivity of the oxidized water sample to obtain a second conductivity; and determining the TOCi value in the water sample according to the first conductivity and the second conductivity. The device comprises: the system comprises a cation removal system, a degassing system, a first conductivity sensor, an oxidation system and a second conductivity sensor which are connected in sequence. The method and device can reduce the back of water sampleThe scene conductivity can be used for measuring most of high-pressure boiler water supply samples, and meanwhile, the sensitivity and accuracy of measuring the TOCi value can be improved.
Description
Technical Field
The invention relates to the technical field of detection instruments, in particular to a method and a device for measuring total organic carbon ion values in high-pressure boiler feed water.
Background
TOCi is known as total organic carbon ion, which refers to the sum of the total carbon content in the organic matter and the content of other hetero atoms that produce anions after oxidation. The water supply of the high-pressure boiler is controlled to be TOCi less than or equal to 500 mug/L according to the standard requirements of GB/T12145-2016 thermal generator set and steam power equipment steam quality. The significance of replacing TOC indexes by TOCi indexes in a water vapor system of a power station is as follows: in the vapor system, organic matters are controlled, and the purpose is mainly to prevent harmful matters generated by the decomposition of the organic matters from corroding equipment such as a steam turbine, and hetero atoms such as S, N, cl in the organic matters are converted into inorganic anions. For the thermodynamic plant steam cycle system, the corrosion of the turbine by these impurities is more severe, so the risk is reflected by the TOC index more than by the TOC index. Therefore, TOCi is a very important control index of high-pressure boiler feed water, and more enterprise laboratories develop the detection of the boiler feed water TOCi after gradually being standardized.
The TOCi analysis system is used for carrying out ultraviolet oxidation treatment on the water sample after ammonia interference is removed from the boiler water supply sample, measuring the conductivity difference value of the water sample before and after oxidation, and calculating to obtain the TOCi value in the water sample. Because the water fed to the high-pressure boiler is generally water with low impurity content, the conductivity difference between the water sample before and after oxidation is very small after ammonia removal of the water sample entering the instrument, and in order to ensure the accuracy of a measurement result, the instrument must use a conductivity detector with very high detection sensitivity to accurately detect the conductivity of 0.001 mu S/cm, and the technical requirement makes TOCi not suitable for the water sample after ammonia removal interference or the water sample with higher conductivity after oxidation, such as the water fed to the high-pressure boiler with higher inorganic carbon content in the industries of power plants, oil refining chemical enterprises and the like. However, in practice, the TOCi value of the high-pressure boiler feed water in a plurality of industries such as power plants, oil refining chemical enterprises and the like is not high, but the conductivity after ammonia removal or the conductivity after oxidation is high (generally more than 1.5 mu S/cm) due to the high background conductivity, so that the TOCi value of the water sample cannot be measured.
Disclosure of Invention
The invention aims to solve the problems that the TOCi value of high-pressure boiler feed water is not high, but the conductivity after ammonia removal or oxidation is high due to the high background conductivity, and a water sample cannot measure the TOCi value, and provides a method and a device for measuring the TOCi value in the high-pressure boiler feed water.
In order to achieve the above object, a first aspect of the present invention provides a method for measuring a total organic carbon ion value in a high pressure boiler feedwater, the method comprising the steps of:
(1) Removing cations from a water sample containing organic carbon ions to obtain a cation-removed water sample, and removing CO from the cation-removed water sample 2 Obtaining a water sample to be detected, and measuring the conductivity of the water sample to be detected to obtain a first conductivity;
(2) Oxidizing the water sample to be detected to obtain an oxidized water sample, and measuring the conductivity of the oxidized water sample to obtain a second conductivity;
(3) And determining the total organic carbon ion value in the water sample according to the first conductivity and the second conductivity.
In a second aspect the present invention provides an apparatus for measuring the total organic carbon ion value in high pressure boiler feedwater, said apparatus comprising: the system comprises a cation removal system, a degassing system, a first conductivity sensor, an oxidation system and a second conductivity sensor which are connected in sequence; wherein,
the cation removal system is used for removing cations in the water sample to obtain a cation-removed water sample;
the degassing system is used for removing CO in the decyang water sample 2 Obtaining a water sample to be detected;
the first conductivity sensor is used for measuring the conductivity of the water sample to be measured;
the oxidation system is used for oxidizing organic matters in the water sample to be detected to obtain an oxidized water sample;
the second conductivity sensor is used for measuring the conductivity of the oxidized water sample.
Through the technical scheme, the invention can obtain the following beneficial effects:
the invention provides a method and a device for measuring TOCi value in high-pressure boiler feed water, which sequentially remove cations and CO in a water sample by combining a cation removing system with a degassing system 2 I.e. adding a CO removal module after the ammonia removal module 2 The water sample is acidic after ammonia removal by a cation removal system, so that carbonate and bicarbonate in the water sample are converted into CO 2 The method and the device for measuring the TOCi value in the water sample can be used for measuring most of high-pressure boiler water supply samples, and the degassing system can remove carbon dioxide and improve the measurement sensitivity and accuracy of the TOCi value. The method and the device for measuring the TOCi value in the water sample provided by the invention have the advantages of simple structure and simplicity and convenience in operation, and are particularly suitable for accurately measuring the TOCi value of the high-pressure boiler feed water in a plurality of industries such as oil refining chemical enterprises.
Drawings
FIG. 1 is a schematic diagram of an apparatus for measuring total organic carbon ion values in a water sample according to the present invention.
Description of the reference numerals
1. Water sample bottle 2, first peristaltic pump 3 and cation removal system
4. Membrane exchange device 5, second peristaltic pump 6 and absorption liquid storage tank
7. First conductivity sensor 8, oxidation system 9, second conductivity sensor
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In the present invention, the "first" and "second" do not limit the present inventors, but only to distinguish operations performed at different stages from elements included in the apparatus.
The first aspect of the invention provides a method for measuring the total organic carbon ion value in high pressure boiler feedwater, the method comprising the steps of:
(1) Removing cations from a water sample containing organic carbon ions to obtain a cation-removed water sample, and removing CO from the cation-removed water sample 2 Obtaining a water sample to be detected, and measuring the conductivity of the water sample to be detected to obtain a first conductivity;
(2) Oxidizing the water sample to be detected to obtain an oxidized water sample, and measuring the conductivity of the oxidized water sample to obtain a second conductivity;
(3) And determining the total organic carbon ion value in the water sample according to the first conductivity and the second conductivity.
The inventors of the present invention have found that, when studying high-pressure boiler feed water as a water sample, cation removal and CO removal are sequentially performed by subjecting high-pressure boiler feed water containing organic carbon ions 2 After that, the background conductivity of the water sample can be reduced, so that the problem that the water sample cannot measure the TOCi value because the conductivity after ammonia removal or the conductivity after oxidation is high due to the fact that the TOCi value of the high-pressure boiler water supply in the prior art is not high is solved, and the measurement sensitivity and accuracy of the TOCi value are improved.
In the present invention, the type of the cation contained in the water sample in the step (1) is not particularly limited, and in general, the cation mainly includes ammonium ion and, in addition, includes a small amount of sodium ion.
In the invention, besides cations, the water sample also comprises inorganic carbon, such as carbonate ions and bicarbonate ions.
In a preferred embodiment of the invention, the conditions for removing cations are such that the removal rate of ammonium ions in the water sample is greater than 99.9% and no organic matter dissolves out to affect the measurement of the value of TOCi.
In the invention, the removal rate of the ammonium ions is calculated by the following formula:
Φ 1 ＝(1-B/A)×100；
in phi, phi 1 The removal rate of ammonium ions is the removal rate of ammonium ions; a is the ammonium radical content in a water sample, and mu g/L; b is the ammonium radical content in the water sample without positive temperature coefficient, and mu g/L. Wherein the ammonium content is measured by ion chromatography.
In a preferred embodiment of the invention, the de-Yang Shuiyang is acidic and has a pH of preferably no more than 5, at which time more than 90% of the inorganic carbon (carbonate and bicarbonate ions) in the de-cationized water sample is converted to CO 2 。
In the present invention, the method for removing cations is not particularly limited as long as the cation removal rate is more than 99.9%, no organic matter is eluted, and the pH of the cation-removed water sample is within the above range. Preferably, the method for removing cations is electrochemical removal of cations.
In a preferred embodiment of the invention, the removal of CO 2 Under conditions such that CO in the decyankee water sample 2 The removal rate of (2) is more than 90%. CO in the water sample with the positive removal function 2 Mainly from the conversion of inorganic carbon such as carbonate ions, bicarbonate ions and the like in a water sample.
In the invention, the CO 2 The removal rate of (2) is calculated by the following formula:
Φ 2 ＝(1-D/C)×100；
in phi, phi 2 Is CO 2 Is not limited by the removal rate of the catalyst; c is CO calculated according to electric conductivity in the water sample with positive removal 2 Content, μg/L; d is the residual CO calculated according to the electric conduction in the water sample to be measured 2 Content, μg/L.
In the present invention, preferably, the CO in the decyang water sample is removed by a membrane exchange method 2 . Specifically, the absorption liquid and the water sample with the removed positive are simultaneously passed through the two sides of the membrane, and the absorption liquid absorbs CO in the water sample with the removed positive 2 Thereby removing CO in the positive water sample 2 Is removed.
In the invention, CO is removed 2 The conductivity ratio of the obtained water sample to be measured is higher than that of the water sample without CO removal 2 The background conductivity of the water sample is greatly reduced, so that the conductivity of most high-pressure boilers after water supply treatment is adapted to the measurement requirement of TOCi (less than 1.5 mu S/cm), and the measurement sensitivity of the TOCi value is improved.
In a preferred embodiment of the present invention, in step (2), the oxidizing conditions are such that the organic matter in the water sample to be tested is oxidized to CO 2 And an inorganic anion.
In the present invention, the method of oxidation is not particularly limited, and oxidation may be performed by a conventional oxidation method in the art. Preferably, the oxidation process comprises: the water sample to be measured passes through a quartz capillary tube, and organic matters in the water sample to be measured are oxidized into CO by irradiation of an ultraviolet lamp 2 And an inorganic anion; wherein the wavelength of the ultraviolet lamp is 235-265nm, the power is 30-60W, and the irradiation time is 2-5min.
In the invention, the TOCi value in the water sample can be obtained according to the measured first conductivity and the measured second conductivity.
In a second aspect the present invention provides an apparatus for measuring the total organic carbon ion value in high pressure boiler feedwater, said apparatus comprising: the system comprises a cation removal system, a degassing system, a first conductivity sensor, an oxidation system and a second conductivity sensor which are connected in sequence; wherein,
the cation removal system is used for removing cations in the water sample to obtain a cation-removed water sample;
the degassing system is used for removing CO in the decyang water sample 2 Obtaining a water sample to be detected;
the first conductivity sensor is used for measuring the conductivity of the water sample to be measured;
the oxidation system is used for oxidizing organic matters in the water sample to be detected to obtain an oxidized water sample;
the second conductivity sensor is used for measuring the conductivity of the oxidized water sample.
The inventors of the present invention have found in research that by using a cation removal system in combination with a degassing system, i.e. adding a CO removal after the ammonia removal module 2 Firstly, removing cations in a water sample by using a cation removing system, and then removing CO by using a degassing system 2 The device can remove more than 90% of inorganic carbon in the water sample and reduce the background conductivity value of the water sample, so that the measuring device of the TOCi value provided by the invention can be used for measuring most of high-pressure boiler water supply samples.
In a preferred embodiment of the invention, the device further comprises: the water sample bottle is connected with the water inlet of the cation removal system through the first peristaltic pump.
In the invention, a schematic diagram of a device for measuring the total organic carbon ion value in a water sample is shown in fig. 1, and the device comprises: the system comprises a water sample bottle 1, a first peristaltic pump 2, a cation removal system 3, a degassing system, a first conductivity sensor 7, an oxidation system 8, a second conductivity sensor 9 and a water outlet which are sequentially connected, wherein the degassing system comprises a membrane exchange device 4, an absorption liquid storage tank 6 and a second peristaltic pump 5.
In a preferred embodiment of the invention, the membrane exchange device 4 is provided with a watery side and an absorption liquid side, which is connected to the absorption liquid storage tank 6 by means of a second peristaltic pump 5; the inlet of the water sample side is connected with the cation removal system 3, and the outlet of the water sample side is connected with the first conductivity sensor 7.
In the invention, as shown in fig. 1, a first peristaltic pump 2 is connected with a water sample bottle 1 and is communicated with a water inlet of a cation removal system 3; the water outlet of the cation removal system 3 is connected with the water sample side inlet of the membrane exchange device 4, the absorption liquid in the absorption liquid tank 6 enters the absorption liquid side inlet of the membrane exchange device 4 through the second peristaltic pump, the absorption liquid side outlet of the membrane exchange device 4 is connected with the absorption liquid storage tank 6, and the water sample side outlet of the membrane exchange device 4 is connected with the water inlet of the first conductivity sensor 7; the water outlet of the first conductivity sensor 7 is connected with the water inlet of the oxidation system 8; the water outlet of the oxidation system 8 is connected with the water inlet of the second conductivity sensor 9; and a water sample at the water outlet of the second conductivity sensor 9 is discharged.
In a preferred embodiment of the present invention, the cation removal system 3 is used for removing cations in a water sample to obtain a water sample with cations removed. The type of the cation contained in the water sample is not particularly limited, and in general, the cation mainly includes ammonium ions and, in addition, includes a small amount of sodium ions.
In the invention, besides cations, the water sample also comprises inorganic carbon, such as carbonate ions and bicarbonate ions.
In a preferred embodiment of the present invention, the cation removal system 3 is an electrically regenerated cation removal system that can continuously treat cations such as ammonium in water at a measured flow rate without the need to replace regenerated ion exchange resins.
In a preferred embodiment of the invention, after the water sample passes through the cation removal system 3, ammonium ions are dynamically removed, the removal rate is more than 99.9%, and no organic matters are dissolved out to influence the measurement result of the TOCi value.
In a preferred embodiment of the invention, the water sample is acidic after passing through the cation removal system 3, and the pH is preferably not higher than 5, at which time more than 90% of the inorganic carbon (carbonate and bicarbonate ions) in the water sample is converted to CO 2 。
In a preferred embodiment of the present invention, the degassing system is used to remove CO from the decyang water sample 2 Obtaining a water sample to be measured. CO in the water sample with the positive removal function 2 Mainly from the conversion of inorganic carbon such as carbonate ions, bicarbonate ions and the like in a water sample.
In the invention, the degassing system is adopted to remove CO in the positive water sample 2 The process of (1) comprises: the absorption liquid in the absorption liquid storage tank 6 enters the absorption liquid in the membrane exchange device 4 through the second peristaltic pump 5CO in the water sample is removed from the liquid side under the action of concentration and pressure difference 2 The absorption liquid side entering the membrane exchange device 4 absorbs the CO on the water sample side with the positive removed 2 The absorption liquid of (2) is returned to the absorption liquid storage tank 6, and CO in the water sample with the positive removed is removed 2 Is removed.
In a preferred embodiment of the invention, the flow rate of the first peristaltic pump 2 is 3-10mL/min, and the flow rate of the second peristaltic pump 5 is 5-15mL/min.
In a preferred embodiment of the invention, the de-cationized water sample is subjected to a degassing system followed by CO 2 The removal rate of (2) is more than 90%.
In the invention, CO is removed 2 The conductivity ratio of the obtained water sample to be measured is higher than that of the water sample without CO removal 2 The background conductivity of the water sample is greatly reduced, so that the conductivity of most high-pressure boilers after water supply treatment is adapted to the measurement requirement of TOCi (less than 1.5 mu S/cm), and the measurement sensitivity of the TOCi value is improved.
In a preferred embodiment of the present invention, the oxidation system 8 is used for oxidizing the organic matters in the water sample to be tested to obtain an oxidized water sample.
In a preferred embodiment of the present invention, the oxidation system 8 is an ultraviolet optical oxidation system, and after the water sample to be measured passes through the oxidation system 8, the organic matters in the water are oxidized into CO 2 And an inorganic anion.
In the invention, the ultraviolet oxidation system comprises a quartz capillary tube and an ultraviolet lamp arranged on the surface of the quartz capillary tube. The specific process for oxidizing the organic matters in the water sample to be detected by using the ultraviolet oxidation system comprises the following steps: when the water sample to be measured passes through the quartz capillary, the ultraviolet lamp directly acts on the water sample to be measured in the quartz capillary, so that organic matters in the water sample to be measured are completely decomposed and converted into CO 2 And an inorganic anion. Wherein, the wavelength of the ultraviolet lamp is preferably 235-265nm, the power is 30-60W, and the irradiation time is 2-5min.
In the invention, the method for measuring the TOCi value in the water sample by adopting the device shown in FIG. 1 comprises the following steps: the method comprises the steps that a water sample in a water sample bottle 1 sequentially passes through a cation removal system 3, a degassing system, a first conductivity sensor 7, an oxidation system 8 and a second conductivity sensor 9 under the drive of a first peristaltic pump 2, and then the TOCi value in the water sample is determined according to the obtained first conductivity and second conductivity.
The present invention will be described in detail by examples. In the following examples of the present invention,
the removal rate of ammonium ions is calculated by the following formula: phi 1 = (1-B/a) ×100; in phi, phi 1 The removal rate of ammonium ions is the removal rate of ammonium ions; a is the ammonium radical content in a water sample, and mu g/L; b is the ammonium radical content in the water sample without positive temperature coefficient, and mu g/L. Wherein the ammonium content is measured by ion chromatography.
CO 2 The removal rate of (2) is calculated by the following formula: phi 2 = (1-D/C) ×100; in phi, phi 2 Is CO 2 Is not limited by the removal rate of the catalyst; c is CO calculated according to electric conductivity in the water sample with positive removal 2 Content, μg/L; d is the residual CO calculated according to the electric conduction in the water sample to be measured 2 Content, μg/L.
In the following examples, the apparatus shown in FIG. 1 was used to measure TOCi values in water samples. Specifically, a water sample in a water sample bottle 1 sequentially passes through a cation removal system 3, a degassing system, a first conductivity sensor 7, an oxidation system 8 and a second conductivity sensor 9 under the drive of a first peristaltic pump 2, and then a TOCi value in the water sample is determined according to the obtained first conductivity and second conductivity; the flow rate of the first peristaltic pump 2 is set to be 4mL/min, and the flow rate of the second peristaltic pump 5 is set to be 6mL/min; in the oxidation system 8, the wavelength of the ultraviolet lamp was 254nm, the power was 50W, and the irradiation time was 3min.
Example 1
The embodiment is used for explaining the removal effect of ammonium ions in the water sample after passing through the cation removal system 3.
The pH value and the concentration of ammonium ions of three different water samples are shown in table 1, the concentrations of ammonium ions in the three water samples after passing through the cation removal system 3, namely the concentration of ammonium ions in the cation removal water sample, are respectively tested, and the removal rate of ammonium ions is calculated, and the results are shown in table 1.
TABLE 1
As can be seen from the results in Table 1, the ammonium ion content is different under different pH conditions, but the pH is changed from 9.0 to 10.0, the concentration of the ammonium ion in the water sample is always less than 1 mug/L after the water sample passes through the cation removal system 3, and the removal rate of the ammonium ion is more than 99.9%.
Example 2
This example is intended to illustrate the effect of the cation removal system 3 on the measurement of TOCi.
Four different water samples were taken and tested for TOCi values, respectively, and the results are shown in Table 2. The four water samples were then separately tested for their TOCi values after passing through the cation removal system 3 and the variation in TOCi values before and after passing through the cation removal system 3 was calculated and the results are shown in Table 2.
TABLE 2
As can be seen from the results of Table 2, the absolute variation of the TOCi content of the water samples with different TOCi contents was not more than 2. Mu.g/L after passing through the cation removal system 3. Indicating that no organics are eluted after passing through the cation removal system 3 to affect the TOCi measurement.
Example 3
This example is illustrative of the CO in a water sample after it has passed through a degassing system 2 Is not limited, and the removal effect of the catalyst is realized.
Taking a water sample with positive removal, and respectively testing the conductivity and CO of the water sample with positive removal 2 The content of the water sample is then determined by a degassing system, the water sample to be measured is obtained, and the conductivity and CO of the water sample to be measured are measured 2 The content and the results are shown in Table 3. The four parameters were tested by shaking in air to change the conductivity of the decationized water sample, and the resultsAs shown in Table 3, CO was calculated 2 Is not limited, and the removal rate of the catalyst is not limited.
TABLE 3 Table 3
As can be seen from the results in Table 3, after passing through the degassing system, CO is removed from the water sample 2 The removal rate of (2) is more than 90%.
Example 4
This example is used to illustrate the change in conductivity in a water sample after passing through a degassing system, and the measurement of the value of TOCi in the water sample.
A water sample was taken and the conductivity of the water sample after passing through the cation removal system 3, the conductivity of the water sample after passing through the degassing system, and the TOCi value of the water sample were respectively measured, and the results are shown in table 4. The three parameters were tested by shaking in air to change the conductivity of the water sample and the results are shown in table 4. Wherein, the water sample is detected by ion chromatography to contain no other anions except carbon dioxide.
TABLE 4 Table 4
As can be seen from the results of Table 4, the same water sample absorbs CO in air 2 After that, the conductivity was changed greatly (from 0.682. Mu.S/cm to 2.108. Mu.S/cm), and CO in the water sample after passing through the degassing system 2 The conductivity of the water sample to be detected is greatly reduced by removing the water sample, the conductivity of the water sample is 2.108 mu S/cm before passing through the degassing system, and the conductivity of the water sample can be reduced to 0.342 mu S/cm, so that the TOCi value of the water sample can be accurately detected.
In summary, the method and the device for measuring the TOCi value in the water sample can solve the problem of water supply of high-pressure boilers in many power plants and oil refining chemical enterprisesThe TOCi value is not high but due to CO 2 The background conductivity is higher, so that the conductivity after ammonia removal or the conductivity after oxidation is high (generally more than 1.5 mu S/cm), and the TOCi value of the water sample cannot be measured. Moreover, the measurement accuracy of the water supply TOCi of the high-pressure boiler can be ensured after the water passes through the membrane exchange device, the error caused by the change of the conductivity is greatly reduced, and an accurate basis is provided for the adjustment of the water working condition.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A method for measuring total organic carbon ion values in high pressure boiler feedwater, the method comprising the steps of:
(1) Removing cations from a water sample containing organic carbon ions to obtain a cation-removed water sample, and removing CO from the cation-removed water sample 2 Obtaining a water sample to be detected, and measuring the conductivity of the water sample to be detected to obtain a first conductivity;
(2) Oxidizing the water sample to be detected to obtain an oxidized water sample, and measuring the conductivity of the oxidized water sample to obtain a second conductivity;
(3) And determining the total organic carbon ion value in the water sample according to the first conductivity and the second conductivity.
2. The method of claim 1, wherein the cations comprise ammonium ions;
preferably, the method for removing cations is electrochemical removal of cations;
preferably, the conditions for removing cations are such that the removal rate of cations in the water sample is greater than 99.9% and no organic matter is dissolved out;
preferably, the pH value of the water sample without positive removal is not higher than 5;
preferably, the removal of CO 2 Under conditions such that CO in the decyankee water sample 2 The removal rate of (2) is more than 90%.
3. A method according to claim 1 or claim 2 wherein in step (2) the oxidising conditions are such that organic matter in the sample of water to be tested is oxidised to CO 2 And an inorganic anion.
4. An apparatus for measuring total organic carbon ion values in high pressure boiler feedwater, said apparatus comprising: the system comprises a cation removal system, a degassing system, a first conductivity sensor, an oxidation system and a second conductivity sensor which are connected in sequence; wherein,
the cation removal system is used for removing cations in the water sample to obtain a cation-removed water sample;
the degassing system is used for removing CO in the decyang water sample 2 Obtaining a water sample to be detected;
the first conductivity sensor is used for measuring the conductivity of the water sample to be measured;
the oxidation system is used for oxidizing organic matters in the water sample to be detected to obtain an oxidized water sample;
the second conductivity sensor is used for measuring the conductivity of the oxidized water sample.
5. The apparatus of claim 4, wherein the apparatus further comprises: the water sample bottle is connected with the water inlet of the cation removal system through the first peristaltic pump.
6. The apparatus of claim 4 or 5, wherein the cation removal system is an electrically regenerative cation removal system;
preferably, the cation comprises an ammonium ion;
preferably, after the water sample passes through the cation removal system, the cation removal rate is greater than 99.9%, and no organic matters are dissolved out;
preferably, the pH value of the water sample without positive removal is not higher than 5.
7. The device of any of claims 4-6, wherein the degassing system comprises a membrane exchange device, an absorption liquid storage tank, and a second peristaltic pump.
8. The device of claim 7, wherein the membrane exchange device is provided with a watery side and an absorption liquid side, the absorption liquid side being connected to the absorption liquid storage tank by a second peristaltic pump; the inlet of the water sample side is connected with the cation removal system, and the outlet of the water sample side is connected with the first conductivity sensor.
9. The apparatus of claim 8, wherein the absorption liquid in the absorption liquid storage tank enters the absorption liquid side through a second peristaltic pump and absorbs CO on the watery side 2 And then returns to the absorption liquid storage tank.
10. The device according to any one of claims 4-9, wherein the oxidation system is an ultraviolet optical oxidation system, and the organic matters in the water are oxidized into CO after the water sample to be tested passes through the oxidation system 2 And an inorganic anion.
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