CN117298825A - Desulfurization slurry oxidation control method and system - Google Patents
Desulfurization slurry oxidation control method and system Download PDFInfo
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- CN117298825A CN117298825A CN202311177456.0A CN202311177456A CN117298825A CN 117298825 A CN117298825 A CN 117298825A CN 202311177456 A CN202311177456 A CN 202311177456A CN 117298825 A CN117298825 A CN 117298825A
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- 239000002002 slurry Substances 0.000 title claims abstract description 148
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 146
- 230000023556 desulfurization Effects 0.000 title claims abstract description 146
- 230000003647 oxidation Effects 0.000 title claims abstract description 113
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 113
- 238000000034 method Methods 0.000 title claims abstract description 37
- 230000003009 desulfurizing effect Effects 0.000 claims abstract description 68
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000001301 oxygen Substances 0.000 claims abstract description 21
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 21
- 230000033116 oxidation-reduction process Effects 0.000 claims abstract description 13
- 230000001105 regulatory effect Effects 0.000 claims abstract description 6
- 230000001276 controlling effect Effects 0.000 claims abstract description 5
- 238000012545 processing Methods 0.000 claims abstract description 4
- 239000010440 gypsum Substances 0.000 claims description 38
- 229910052602 gypsum Inorganic materials 0.000 claims description 38
- 238000012360 testing method Methods 0.000 claims description 15
- 238000005070 sampling Methods 0.000 claims description 12
- 238000005273 aeration Methods 0.000 claims description 9
- 238000004364 calculation method Methods 0.000 claims description 9
- 239000000523 sample Substances 0.000 claims description 5
- 238000011010 flushing procedure Methods 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000004891 communication Methods 0.000 claims 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 abstract description 7
- 229940079826 hydrogen sulfite Drugs 0.000 abstract description 5
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 235000019738 Limestone Nutrition 0.000 description 3
- 239000006028 limestone Substances 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000006213 oxygenation reaction Methods 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 235000015424 sodium Nutrition 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/346—Controlling the process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
- B01D53/502—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific solution or suspension
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
- B01D53/504—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/80—Semi-solid phase processes, i.e. by using slurries
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention relates to a desulfurization slurry oxidation control method and a desulfurization slurry oxidation control system, wherein the method comprises the following steps: measuring dissolved oxygen, oxidation-reduction potential, PH value and CaSO of slurry in desulfurizing tower 4 Density or (v) ofIs a concentration of (2); for the dissolved oxygen, the redox potential, the pH, the CaSO 4 Or the density of (1)And (3) processing and calculating to obtain the oxidation rate of slurry in the desulfurizing tower, and regulating and controlling the output of the oxidation fan according to the oxidation rate. The invention uses dissolved oxygen DO, oxidation-reduction potential ORP, pH value PH and density or concentrationThe four parameters are controlled in a combined way, and the oxidation condition of the hydrogen sulfite in the slurry is fed back in real time, so that a guiding system accurately adjusts the supply quantity of oxidation wind, the energy-saving operation of a fan is realized, and the full oxidation of the desulfurization slurry is ensured to the greatest extent.
Description
Technical Field
The invention relates to the field of desulfurization, in particular to a desulfurization slurry oxidation control method and system.
Background
The wet desulfurization process is short by SO 2 Firstly diffusing into the slurry, and then generating acid-base neutralization reaction in the slurry to generate H 2 SO 3 、HSO 3- And SO 3 2- In the normal operation PH range of the desulfurization slurry, the desulfurization slurry mainly adopts HSO 3- Is present and subsequently oxidized to sulfate by the action of oxidizing air. At present, most power plants only perform simple acid-base control on slurry oxidation, namely, the pH of desulfurization slurry is ensured to be maintained at weak acidity, generally about 5.5, and the internal oxidation degree is not strictly controlled. On the one hand, the energy waste of the oxidation fan is caused by the excessive supply of the oxidation air in the system, so that the energy consumption of the FGD system is increased, and on the other hand, the desulfurization efficiency is reduced and the gypsum dehydration is difficult due to the insufficient supply of the oxidation air in part of the desulfurization tower.
Disclosure of Invention
The invention aims to solve the technical problem of providing a desulfurization slurry oxidation control method and a desulfurization slurry oxidation control system, which not only realize energy-saving operation of a fan, but also ensure full oxidation of desulfurization slurry to the maximum extent.
The technical scheme for solving the technical problems is as follows: a desulfurization slurry oxidation control method comprises the following steps:
measuring dissolved oxygen of slurry in the desulfurizing tower;
measuring the oxidation-reduction potential of the slurry in the desulfurizing tower;
measuring the PH value of slurry in the desulfurizing tower;
when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is measured 4 Is a density of (3); when no desulfurization gypsum is generated in the desulfurization tower, measuring the slurry in the desulfurization towerIs a concentration of (2);
for the dissolved oxygen, the redox potential, the pH, the CaSO 4 Or the density of (1)And (3) processing and calculating to obtain the oxidation rate of slurry in the desulfurizing tower, and regulating and controlling the output of the oxidation fan according to the oxidation rate.
On the basis of the technical scheme, the invention can be improved as follows.
Further, the specific process for obtaining the oxidation rate of the slurry in the desulfurizing tower is as follows:
calculating the slurry in the desulfurizing tower according to the dissolved oxygen, the oxidation-reduction potential and the PH value based on the Nernst equationOr->Is a concentration of (2);
when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is treated 4 Is converted into CaSO in slurry in the desulfurizing tower 4 Is a concentration of (2);
according to the slurry in the desulfurizing towerOr->Is the concentration of CaSO in slurry in the desulfurizing tower 4 Or->And (3) calculating the oxidation rate of the slurry in the desulfurizing tower.
Further, the slurry in the desulfurizing tower was calculatedOr->The formula of the concentration of (2) is:
wherein,is +.>Or->Is a concentration of (2);
DO is the dissolved oxygen, E is the redox potential, PH is the PH value, and k and b are empirical parameters.
Further, when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is treated 4 Is converted into CaSO in slurry in the desulfurizing tower 4 The formula of the concentration of (2) is:
wherein,is desulfurizing tower internal slurryCaSO in liquid 4 ρ is the concentration of CaSO in the slurry in the desulfurizing tower 4 Is a density of (3).
Further, when desulfurization gypsum is generated in the desulfurization tower, the calculation formula of the oxidation rate of slurry in the desulfurization tower is as follows:
or->
When no desulfurization gypsum is generated in the desulfurization tower, the calculation formula of the oxidation rate of slurry in the desulfurization tower is as follows:
or->
Wherein,is the oxidation rate of slurry in the desulfurizing tower;
when desulfurization gypsum is generated in the desulfurization tower, caSO is contained in slurry in the desulfurization tower 4 CaSO in slurry in desulfurizing tower formed by density conversion 4 Is a concentration of (2);
in order to ensure that the slurry in the desulfurizing tower is +.>Is a concentration of (2); />Is +.>Concentration of->Is +.>Is a concentration of (3).
Based on the desulfurization slurry oxidation control method, the invention also provides a desulfurization slurry oxidation control system.
A desulfurization slurry oxidation control system is applied to the desulfurization slurry oxidation control method, and comprises the following steps:
a desulfurizing tower;
the aeration device is used for aeration and is arranged in the desulfurization tower;
the oxidation fan is used for providing oxidation wind, is arranged outside the desulfurization tower and is communicated with the desulfurization tower;
the tester comprises a DO tester for measuring dissolved oxygen of slurry in the desulfurizing tower, an ORP tester for measuring oxidation-reduction potential of the slurry in the desulfurizing tower, a PH tester for measuring PH value of the slurry in the desulfurizing tower and a preset tester, wherein the DO tester, the ORP tester, the PH tester and the preset tester are all arranged on the desulfurizing tower;
the analog input point of the PLC is electrically connected with the DO tester, the ORP tester, the PH tester and the preset tester respectively, and the analog output point of the PLC is electrically connected with the oxidation blower;
wherein, when the desulfurization gypsum is generated in the desulfurization tower, the preset tester is specifically a density tester, and when the desulfurization gypsum is not generated in the desulfurization tower, the preset tester is specificallyA concentration detector.
On the basis of the technical scheme, the invention can be improved as follows.
Further, the desulfurization tower also comprises a sampling test tank, wherein the sampling test tank is arranged outside the desulfurization tower and is communicated with the desulfurization tower; the DO tester, the ORP tester and the PH tester are all disposed on the sampling test tank.
Further, a flushing probe is arranged in the sampling test tank.
Further, the tester is provided with one or more sets, and the DO tester, the ORP tester, the PH tester and the preset tester in the one or more sets of the tester are all electrically connected to analog input points of the PLC.
Further, the driving motor of the oxidation fan is specifically a variable frequency motor.
The beneficial effects of the invention are as follows: according to the desulfurization slurry oxidation control method and system, through combined control of dissolved oxygen, oxidation-reduction potential, pH value and slurry density or concentration, the oxidation condition of hydrogen sulfite in the slurry is fed back in real time, so that the system is guided to accurately adjust the supply amount of oxidation wind, the energy-saving operation of a fan is realized, and the full oxidation of the desulfurization slurry is ensured to the greatest extent.
Drawings
FIG. 1 is a flow chart of a desulfurization slurry oxidation control method of the present invention;
FIG. 2 is a graph of sulfite to bisulfite ratios at different pH and temperature conditions;
FIG. 3 is a block diagram of a desulfurization slurry oxidation control system according to the present invention.
Detailed Description
The principles and features of the present invention are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the invention and are not to be construed as limiting the scope of the invention.
As shown in fig. 1, a desulfurization slurry oxidation control method includes the steps of:
measuring dissolved oxygen of slurry in the desulfurizing tower;
measuring the oxidation-reduction potential of the slurry in the desulfurizing tower;
measuring the PH value of slurry in the desulfurizing tower;
when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is measured 4 Is a density of (3); when no desulfurization gypsum is generated in the desulfurization tower, measuring the slurry in the desulfurization towerIs a concentration of (2);
for the dissolved oxygen, the redox potential, the pH, the CaSO 4 Or the density of (1)And (3) processing and calculating to obtain the oxidation rate of slurry in the desulfurizing tower, and regulating and controlling the output of the oxidation fan according to the oxidation rate.
In this embodiment, the specific process for obtaining the oxidation rate of the slurry in the desulfurizing tower is as follows:
calculating the slurry in the desulfurizing tower according to the dissolved oxygen, the oxidation-reduction potential and the PH value based on the Nernst equationOr->Is a concentration of (2);
when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is treated 4 Is converted into CaSO in slurry in the desulfurizing tower 4 Is a concentration of (2);
according to the slurry in the desulfurizing towerOr->Concentration of (2)CaSO in slurry in desulfurizing tower 4 Or->And (3) calculating the oxidation rate of the slurry in the desulfurizing tower.
In the method of the invention, reference is made toMainly from the Nernst equation corresponding to the ORP test:
due to standard electrode potential E θ Substantially a constant, will beH + The logarithmic operation with DO is regarded as an integral variable, and the whole formula can be modified into the following formula in order to be suitable for the data sampled by the instrument to carry out the importing operation:
further, to characterize real-time in the slurryThe concentration, this formula can be modified to the following semi-empirical formula:
that is, the real-time estimated value of the hydrogen sulfite concentration is:
wherein,is +.>Is a concentration of (2);
DO is the dissolved oxygen, E is the redox potential (i.e., the ORP value at the redox site), PH is the pH, and k and b are empirical parameters.
Specifically, the k and b values are empirical parameters corresponding to different types of slurries, and may be determined by configuring different known concentrationsAnd (3) preparing solutions with DO of different concentrations, measuring through a DO tester, an ORP tester and a PH tester, fitting k and b parameter tables under different slurry conditions through parameters, and conveniently calling according to the slurry conditions during program calculation.
When it is measured thatAt the concentration of +.>Replaced by->And (3) obtaining the product.
In the measuring process, after the alkaline desulfurizing agent washes the flue gas, a large amount of flue gas is generated(or->) The sulfite to bisulfite ratios are different at different slurry PH and temperature conditions, such as shown in fig. 2. Taking limestone gypsum method as an example, the pH of the slurry is generally controlledAbout 5.5, wherein the hydrogen sulfite content exceeds 95%, and selectingTo measure the target, the concentration thereof is measured. When the pH value of the slurry is controlled to be about 10, the sulfite accounts for more than 95%, and the pH value is selected>To measure the target, the concentration thereof is measured.
In the limestone-gypsum method and the slaked lime-gypsum method, sulfate radical mainly adopts CaSO 4 ·2H 2 O exists in a form to characterize CaSO in real time in the slurry 4 ·2H 2 The O concentration can be calculated by the value of the densitometer; namely, when the desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is treated 4 Is converted into CaSO in slurry in the desulfurizing tower 4 The formula of the concentration of (2) is:
wherein,is CaSO in slurry in the desulfurizing tower 4 ρ is the concentration of CaSO in the slurry in the desulfurizing tower 4 Is a density of (3); the formula is a semi-empirical formula, and the influence of other impurity components is ignored.
Of course, in limestone-gypsum method and slaked lime-gypsum method, caSO is in real time in the slurry 4 ·2H 2 The O concentration can also be measured on-line using other physical methods. Specifically, in the limestone-gypsum method and the slaked lime-gypsum method, caSO is carried out in the slurry in real time 4 ·2H 2 The O concentration can be combined with the result of the manual assay according to the density value to summarize a density and CaSO 4 ·2H 2 And (3) comparing the concentration of O with a relation table, and directly calling the numerical value in an experience table when the program is calculated.
In addition, in the wet desulfurization method without generating desulfurization gypsum precipitate,the ion state exists in the slurry, can be detected in real time by adopting an online measuring instrument, and can be combined with the result of manual assay according to the density value to summarize a density and +.>The comparison relation table of the concentration directly calls the numerical value in the experience table when the program calculates.
When desulfurization gypsum is generated in the desulfurization tower, the calculation formula of the oxidation rate of slurry in the desulfurization tower is as follows:
or->
When no desulfurization gypsum is generated in the desulfurization tower, the calculation formula of the oxidation rate of slurry in the desulfurization tower is as follows:
or->
Wherein,is the oxidation rate of slurry in the desulfurizing tower;
when desulfurization gypsum is generated in the desulfurization tower, caSO is contained in slurry in the desulfurization tower 4 CaSO in slurry in desulfurizing tower formed by density conversion 4 Is a concentration of (2);
in order to ensure that the slurry in the desulfurizing tower is +.>Is a concentration of (2); />Is +.>Concentration of->Is +.>Is a concentration of (3).
After comprehensively calculating the oxidation rate value, regulating and controlling the set minimum limit value of the oxidation rate according to the project, wherein the oxidation rate requirement of a limestone-gypsum method is generally more than 95%, and when the oxidation rate exceeds the limit value, reducing the output of an oxidation fan according to the set ratio so as to realize energy conservation; when the oxidation rate is lower than the limit value, the output of the oxidation blower is increased according to the set ratio so as to improve the oxidation rate.
Based on the desulfurization slurry oxidation control method, the invention also provides a desulfurization slurry oxidation control system.
As shown in fig. 3, a desulfurization slurry oxidation control system, applied to the desulfurization slurry oxidation control method described above, includes:
a desulfurizing tower 1;
an aeration device 2 for aeration, the aeration device 2 being disposed within the desulfurization tower 1;
an oxidation fan 3 for providing oxidation wind, wherein the oxidation fan 3 is arranged outside the desulfurization tower 1 and is communicated with the desulfurization tower 1;
the tester comprises a DO tester 4 for measuring dissolved oxygen of slurry in the desulfurizing tower 1, an ORP tester 5 for measuring oxidation-reduction potential of the slurry in the desulfurizing tower 1, a PH tester 6 for measuring PH value of the slurry in the desulfurizing tower 1 and a preset tester 7, wherein the DO tester 4, the ORP tester 5, the PH tester 6 and the preset tester 7 are all arranged on the desulfurizing tower 1;
the analog input point of the PLC controller 8 is electrically connected with the DO tester 4, the ORP tester 5, the PH tester 6 and the preset tester 7 respectively, and the analog output point of the PLC controller 8 is electrically connected with the oxidation blower 3;
wherein, when the desulfurization gypsum is generated in the desulfurization tower 1, the preset tester 7 is specifically a density tester, and when the desulfurization gypsum is not generated in the desulfurization tower 1, the preset tester 7 is specifically an SO 4 2- A concentration detector.
The desulfurization slurry oxidation control system is mainly used for carrying out precise oxidation control on wet desulfurization slurry, is suitable for, but not limited to, a desulfurization tower 1 adopting limestone, slaked lime, sodium alkali or other alkaline absorbents, and the form of the desulfurization tower 1 is not limited to a spray tower, a bubble tower, a packed tower or other tower bodies for realizing desulfurization through gas-liquid contact.
In a desulfurization slurry oxidation control system of the present invention, the aeration device 2 is not limited to an oxidation air pipe network, an oxidation spray gun and stirring or other aeration oxygenation devices.
The desulfurization slurry oxidation control system also comprises a sampling test tank 9, wherein the sampling test tank 9 is arranged outside the desulfurization tower 1 and is communicated with the desulfurization tower 1; the DO tester 4, the ORP tester 5 and the PH tester 6 are all arranged on the sampling test tank 9 so as to be convenient to manage, and a flushing probe is arranged on the sampling test tank 9, so that the flushing water can be sprayed out to regularly flush the testing probe of the tester, and the measurement accuracy is ensured. Of course, the DO tester 4, the ORP tester 5, the PH tester 6, and the preset tester 7 may be directly provided on the body of the desulfurizing tower 1. In this embodiment, the DO tester 3, the ORP tester 4, and the PH tester 5 are installed on the same sampling test tank 9; if the preset tester 7 is installed on the tower body.
Considering that measurement errors may be caused by scaling or probe aging problems after the measurement of the tester for a long time, it is recommended that the tester in the desulfurization slurry oxidation control system of the invention is provided with a plurality of redundancy sets.
For the desulfurization slurry of limestone gypsum method, the actual content of dissolved oxygen DO is 0-5 mg/L, ORP value is 0-200 mV, PH is 5-6, in order to ensure the accuracy of control calculation of PLC controller 8, these several types of testers require relatively high accuracy value, in one embodiment DO tester 4 recommends to use the instrument of about 1% accuracy class of measured value, ORP tester 5 recommends to use the instrument of about 1mV accuracy class, PH tester 6 recommends to use the instrument of about 0.01PH accuracy class, and density tester selects differential pressure type densimeter.
The invention relates to a PLC controller 8 which is needed to be equipped in a desulfurization slurry oxidation control system, except DO, ORP, PH and CaSO which are necessary 4 Density ρ (or)The concentration of the analog input point and the analog output point regulated by the oxidation fan), and the input and output points of the manual calibration and other purposes are also reserved.
In the desulfurization slurry oxidation control system, the oxidation fan 3 adopts a variable frequency motor so as to be matched with an adjusting instruction provided by the PLC 8. The PLC controller 8 receives DO, ORP, PH and CaSO 4 Density ρ (or)The concentration of the sulfite) and the calcium sulfate (or sulfate radical) according to a built-in algorithm, and further calculating the oxidation degree of the sulfite. In this example, the oxidation rate of 95% was set as the lowest limit value due to the quality and dehydration performance requirements of the desulfurized gypsum. When the result calculated by the PLC controller 8 is lower than the minimum value, the PLC controllerThe system 8 sends out the instruction of increasing the frequency of the oxidation fan 3, then the frequency is kept unchanged, if the oxidation rate is still not improved after the set time, the fan frequency is continuously increased until the oxidation rate reaches the minimum limit value, and finally the frequency operation is stabilized. If the PLC controller 8 analyzes that the current oxidation rate is far over 95 percent, the PLC controller 8 sends a frequency reducing instruction to the oxidation fan 3, after the set time, if the oxidation rate is not reduced, the fan frequency is continuously reduced until the oxidation rate reaches a minimum limit value, and the frequency is kept unchanged.
In this embodiment, in order to ensure reliability, the tester needs to be periodically flushed and calibrated, so as to prevent the control failure caused by measurement errors. Meanwhile, the operator should periodically test the slurry composition, monitor whether the calculation program is shifted or not, input the measured value into the PLC controller 8, and input the manually measured slurry composition parameter so that it corrects its built-in calculation formula according to the measured value to correct the calculation model.
In summary, the desulfurization slurry oxidation control method and system of the invention comprises the steps of dissolving oxygen DO, oxidation-reduction potential ORP, pH value PH and CaSO 4 Density ρ (or)The concentration of the hydrogen sulfite in the slurry is fed back in real time, so that the system is guided to accurately adjust the supply amount of the oxidation wind, the energy-saving operation of a fan is realized, and the full oxidation of the desulfurization slurry is ensured to the greatest extent.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (10)
1. The desulfurization slurry oxidation control method is characterized by comprising the following steps of:
measuring dissolved oxygen of slurry in the desulfurizing tower;
measuring the oxidation-reduction potential of the slurry in the desulfurizing tower;
measuring the PH value of slurry in the desulfurizing tower;
when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is measured 4 Is a density of (3); when no desulfurization gypsum is generated in the desulfurization tower, measuring the slurry in the desulfurization towerIs a concentration of (2);
for the dissolved oxygen, the redox potential, the pH, the CaSO 4 Or the density of (1)And (3) processing and calculating to obtain the oxidation rate of slurry in the desulfurizing tower, and regulating and controlling the output of the oxidation fan according to the oxidation rate.
2. The desulfurization slurry oxidation control method according to claim 1, characterized in that the specific process for obtaining the oxidation rate of the slurry in the desulfurization tower is:
calculating the slurry in the desulfurizing tower according to the dissolved oxygen, the oxidation-reduction potential and the PH value based on the Nernst equationOr->Is a concentration of (2);
when desulfurization gypsum is generated in the desulfurization tower, caSO in slurry in the desulfurization tower is treated 4 Is converted into CaSO in slurry in the desulfurizing tower 4 Is a concentration of (2);
according to the slurry in the desulfurizing towerOr->Is the concentration of CaSO in slurry in the desulfurizing tower 4 Or->And (3) calculating the oxidation rate of the slurry in the desulfurizing tower.
3. The desulfurization slurry oxidation control method according to claim 2, wherein the slurry in the desulfurizing tower is calculatedOr->The formula of the concentration of (2) is:
wherein,is +.>Or->Is a concentration of (2);
DO is the dissolved oxygen, E is the redox potential, PH is the PH value, and k and b are empirical parameters.
4. The desulfurization slurry oxidation control method according to claim 2, wherein when desulfurization gypsum is produced in the desulfurization tower, caSO in the slurry in the desulfurization tower is removed 4 Is converted into CaSO in slurry in the desulfurizing tower 4 The formula of the concentration of (2) is:
wherein,is CaSO in slurry in the desulfurizing tower 4 ρ is the concentration of CaSO in the slurry in the desulfurizing tower 4 Is a density of (3).
5. The desulfurization slurry oxidation control method according to any one of claims 1 to 4, wherein when desulfurization gypsum is produced in the desulfurization tower, the calculation formula of the oxidation rate of the slurry in the desulfurization tower is:
or->
When no desulfurization gypsum is generated in the desulfurization tower, the calculation formula of the oxidation rate of slurry in the desulfurization tower is as follows:
or->
Wherein,is the oxidation rate of slurry in the desulfurizing tower;
when the desulfurization gypsum is generated in the desulfurization tower, the slurry in the desulfurization towerCaSO in 4 CaSO in slurry in desulfurizing tower formed by density conversion 4 Is a concentration of (2);
in order to ensure that the slurry in the desulfurizing tower is +.>Is a concentration of (2); />Is +.>Concentration of->Is +.>Is a concentration of (3).
6. A desulfurization slurry oxidation control system, characterized by being applied to the desulfurization slurry oxidation control method according to any one of claims 1 to 5, comprising:
a desulfurizing tower;
the aeration device is used for aeration and is arranged in the desulfurization tower;
the oxidation fan is used for providing oxidation wind, is arranged outside the desulfurization tower and is communicated with the desulfurization tower;
the tester comprises a DO tester for measuring dissolved oxygen of slurry in the desulfurizing tower, an ORP tester for measuring oxidation-reduction potential of the slurry in the desulfurizing tower, a PH tester for measuring PH value of the slurry in the desulfurizing tower and a preset tester, wherein the DO tester, the ORP tester, the PH tester and the preset tester are all arranged on the desulfurizing tower;
the analog input point of the PLC is electrically connected with the DO tester, the ORP tester, the PH tester and the preset tester respectively, and the analog output point of the PLC is electrically connected with the oxidation blower;
when no desulfurization gypsum is generated in the desulfurization tower, the preset tester is specifically an SO (SO) 4 2- A concentration detector.
7. The desulfurization slurry oxidation control system according to claim 6, further comprising a sampling test tank disposed outside the desulfurization tower and in communication with the desulfurization tower; the DO tester, the ORP tester and the PH tester are all disposed on the sampling test tank.
8. The desulfurization slurry oxidation control system according to claim 7, wherein a flushing probe is disposed within the sampling test tank.
9. The desulfurization slurry oxidation control system according to claim 6, wherein the tester is provided with one or more sets, and wherein the DO tester, the ORP tester, the PH tester and the predetermined tester of the one or more sets are electrically connected to an analog input point of the PLC controller.
10. The desulfurization slurry oxidation control system according to claim 6, wherein the drive motor of the oxidation blower is specifically a variable frequency motor.
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