A method for controlling the addition of ammonia water to condensate

Abstract

The present application relates to the technical field of ammonia dosing control of condensate water, and more particularly to a method for ammonia dosing control of condensate water, comprising: step one, obtaining the pH value detected at a sampling point, combining a preset pH target value, and calculating the output frequency of a dosing pump frequency converter; step two, obtaining the conductivity detected at the sampling point, and controlling the adjustment speed of the dosing pump frequency according to the difference between the conductivity and a reference value; step three, controlling the operation of the dosing pump according to the output frequency and the adjustment speed, and re-executing step one when the pH value detected at the sampling point changes, to form a closed-loop control; in step one, the pH target value is pre-adjusted according to the load change of a steam turbine unit; the target pH value of the condensate water pH value adjustment process is adjusted by using prediction data, to achieve the purpose of pre-adjusting the condensate water, reduce the influence of sudden increase or decrease of the condensate water flow on the condensate water pH during deep peak shaving, and improve the stability of the operation of the condensate water system.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia dosing control for condensate water, and more particularly to a method for controlling ammonia dosing for condensate water. Background Art

[0002] The thermal system of a thermal power plant is primarily constructed of steel, with the steam turbine at its core. Superheated steam drives the turbine to produce condensate, which is then refined and recycled. To prevent condensate from corroding the thermal system, ammonia is typically added to the condensate to maintain the pH of the condensate and feed water within a reasonable range. Therefore, precisely controlling the amount of ammonia added is a key requirement for condensate recycling.

[0003] In the prior art, sampling points and ammonia addition points are set on the main pipe at the outlet of the fine treatment system to detect and adjust the pH value of the condensate. However, the adjustment process is periodic and has a delay for large-scale adjustment processes.

[0004] During the operation of thermal power plants, peak load regulation occurs. This requires adjusting the load of the steam turbine units upwards or downwards. Peak load regulation is short, and the turbine unit load increases rapidly, resulting in significant changes in the condensate circulation flow rate. Conventional condensate regulation methods can be delayed. Both low and high pH values ​​can adversely affect the equipment in the system.

[0005] Therefore, how to reduce the impact of deep peak regulation on the pH value of condensate water is an urgent problem that technicians in this field need to solve. Summary of the Invention

[0006] In view of this, the present invention provides a method for controlling the dosing of ammonia water into condensate water, which uses predicted data to adjust the target pH value of the condensate water pH adjustment process, thereby achieving the purpose of pre-regulating the condensate water, reducing the impact of the sudden increase or decrease in condensate water flow rate on the condensate water pH during deep peak regulation, and improving the stability of the condensate water system operation.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] Preferably, the above-mentioned method for controlling the dosing of ammonia water into condensate water comprises:

[0009] A dosing point and a sampling point are arranged on the outlet main pipe of the condensate polishing system; wherein the sampling point is arranged after the dosing point;

[0010] Step 1: Obtain the pH value detected at the sampling point, and calculate the output frequency of the dosing pump inverter in combination with a preset pH target value;

[0011] Step 2: obtaining the conductivity detected at the sampling point, and controlling the adjustment speed of the dosing pump frequency according to the difference between the conductivity and a reference value;

[0012] Step 3: controlling the operation of the dosing pump according to the output frequency and the adjustment speed, and re-executing step 1 when a pH value change is detected at the sampling point to form a closed-loop control;

[0013] In the step 1, the pH target value is pre-adjusted according to the load change of the steam turbine unit.

[0014] Preferably, in the above-mentioned ammonia dosing control method for condensate water, obtaining the pH value detected at the sampling point and calculating the output frequency of the dosing pump inverter in combination with a preset pH target value include:

[0015] Determine the calculation formula for the inverter output frequency of the dosing pump;

[0016] updating a correction factor in a calculation formula according to the current pH value and the pH target value;

[0017] The update formula is:

[0018] Where A is the correction coefficient after update, A1 is the correction coefficient before update, pH1 is the target pH value of condensate water, and pH2 is the current pH value of condensate water;

[0019] Obtaining the condensate flow rate and conductivity detected at the sampling point, the pH target value, the flow rate and stroke of the dosing pump, and the updated correction coefficient, and calculating the frequency of the dosing pump;

[0020] The calculation formula is:

[0021]

[0022] Among them, A is the updated correction coefficient, HZ is the target output frequency of the dosing pump inverter, pH1 is the pH target value, Q1 is the condensate flow rate, Q2 is the dosing pump flow rate, and J is the stroke of the dosing pump.

[0023] Preferably, in the above-mentioned ammonia dosing control method for condensate water, obtaining the conductivity detected at the sampling point and controlling the adjustment speed of the dosing pump frequency according to the difference between the conductivity and a reference value include:

[0024] Obtain all the conductivity of the condensed water detected within the set time period of the sampling point, and calculate the effective value of all the conductivities. The calculation formula is:

[0025]

[0026] Wherein, c is the effective value of all conductivity within the set time period of the sampling point, n is the number of detections within the set time period of the sampling point, C i is the conductivity value of each test;

[0027] The difference between the effective value of the conductivity and the preset reference value is calculated, and the adjustment speed of the dosing pump frequency is adjusted according to the size of the difference; wherein, the larger the difference, the faster the adjustment speed.

[0028] Preferably, in the above-mentioned ammonia dosing control method for condensate water, the adjusting speed of the dosing pump frequency according to the size of the difference includes:

[0029] According to the size of the difference A, the adjustment speed B of the dosing pump frequency is adjusted.

[0030] Preset difference matrix A0, set A0(A1, A2, A3, A4), where A1 is the first preset difference, A2 is the second preset difference, A3 is the third preset difference, A4 is the fourth preset difference, and A1<A2<A3<A4;

[0031] A regulating coefficient matrix C0 for regulating the regulating speed B is preset, and C0(C1, C2, C3) is set, where C1 is a first preset regulating coefficient, C2 is a second preset regulating coefficient, C3 is a third preset regulating coefficient, and 1<C1<C2<C3<1.2;

[0032] According to the relationship between the difference value A and the data of the preset difference matrix A0, the adjustment coefficient of the adjustment speed B of the dosing pump frequency is determined, and the current adjustment speed B is adjusted:

[0033] When A<A1, there is no need to adjust the adjustment speed B of the dosing pump frequency;

[0034] When A1≤A<A2, the first preset adjustment coefficient C1 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C1;

[0035] When A2≤A<A3, the second preset adjustment coefficient C2 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C2;

[0036] When A3≤A<A4, the third preset adjustment coefficient C3 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C3.

[0037] Preferably, in the above-mentioned method for controlling the dosing of ammonia water into condensed water, before calculating the effective value of the conductivity, the method includes:

[0038] Sort all conductivities by numerical value and obtain the median value of all conductivities;

[0039] Divide all conductivity data into ten equal parts; based on the median value, take the conductivity of the two parts greater than the median value as the upper value, and take the conductivity of the two parts less than the median value as the lower value;

[0040] An upper limit value and a lower limit value are calculated based on the upper value and the lower value, wherein the upper limit value and the lower limit value are calculated by the following formulas: Q3=Q1+1.5*(Q1-Q2), Q4=Q2-1.5*(Q1-Q2); wherein Q1 is the upper value, Q2 is the lower value, Q3 is the upper limit value, and Q4 is the lower limit value;

[0041] In all conductivity data, data that is greater than the upper limit value Q3 or less than the lower limit value Q4 is deleted.

[0042] Preferably, in the above-mentioned ammonia dosing control method for condensate water, when a pH value change is detected at the sampling point, re-execution of step 1 includes:

[0043] Preset a normal range of condensate pH value, obtain the current pH value of the condensate detected at the collection point, compare and analyze the current pH value with the normal pH range, and adjust the time for re-performing step 1;

[0044] A condensate pH value adjustment cycle is preset, and a detection period and an acceleration period are set within the adjustment cycle; wherein the detection period is at the beginning of the adjustment cycle, the acceleration period is at the end of the adjustment cycle, and the detection period and the acceleration period do not overlap;

[0045] After the frequency of the dosing pump is adjusted, the timing of the adjustment cycle is started;

[0046] If the current pH value is within the normal pH range, the timing of the adjustment cycle proceeds normally;

[0047] When the timing of the adjustment cycle does not reach the acceleration time period:

[0048] If the current pH value exceeds the normal pH range, adjusting the timing of the adjustment period to the beginning of the acceleration period;

[0049] When the timing of the adjustment cycle is within the acceleration time period:

[0050] If the current pH value exceeds the normal pH value range, the timing of the adjustment period is adjusted to the end of the adjustment period, and step 1 is performed again.

[0051] Preferably, in the above-mentioned ammonia dosing control method for condensate water, the pre-adjustment of the pH target value according to the load change of the steam turbine unit includes:

[0052] A load change threshold is preset, a load prediction change curve of the steam turbine unit is obtained, and the load change time is determined according to the load change curve and the load change threshold; wherein the judgment time interval of the load change threshold is a preset unit time length;

[0053] Determine the predicted load after the unit time period has elapsed when the load changes according to the load change time;

[0054] Obtain historical data of the steam turbine unit, match it according to the predicted load, and extract the condensate flow rate of the outlet main pipe of the fine treatment system corresponding to the predicted load;

[0055] The pH target value is pre-adjusted according to the current condensate flow rate and the predicted condensate flow rate; if the current condensate flow rate is less than the predicted condensate flow rate, the pH target value is lowered; if the current condensate flow rate is greater than the predicted condensate flow rate, the pH target value is increased.

[0056] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are:

[0057] 1. The target pH value of the condensate pH adjustment process is adjusted using the predicted data to achieve the purpose of pre-regulating the condensate, reduce the impact of the sudden increase or decrease in condensate flow on the condensate pH during deep peak regulation, and improve the stability of the condensate system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0059] Figure 1 The accompanying drawing is a schematic flow diagram of the method of the present invention. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0061] In the present invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless expressly limited otherwise. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; "connected" can mean a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0062] In the description of the present invention, it should be understood that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0063] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0064] Example 1

[0065] like Figure 1 As shown, the embodiment of the present invention discloses a method for controlling the dosing of ammonia water into condensate water, comprising:

[0066] A dosing point and a sampling point are set on the outlet main pipe of the condensate polishing system; wherein, the sampling point is set after the dosing point;

[0067] Step 1: Obtain the pH value detected at the sampling point and calculate the output frequency of the dosing pump inverter based on the preset pH target value;

[0068] Step 2: Obtain the conductivity detected at the sampling point, and control the adjustment speed of the dosing pump frequency according to the difference between the conductivity and the reference value;

[0069] Step 3: Control the operation of the dosing pump according to the output frequency and the adjustment speed. When a change in pH value is detected at the sampling point, step 1 is re-executed to form a closed-loop control;

[0070] In step 1, the pH target value is pre-adjusted according to the load change of the steam turbine unit.

[0071] In this embodiment, the sampling point collects the pH value of the condensate, the flow rate of the outlet main pipe of the fine treatment system, the conductivity, and the conductivity of ammonia water in the condensate; the detection of all the above values ​​is the existing technology commonly known to people in this field.

[0072] In this embodiment, the sampling point is located 20 m behind the dosing point;

[0073] In this example, the pH target value is 9.4;

[0074] The beneficial effects of the above embodiment are: using predicted data to adjust the target pH value of the condensate water pH value adjustment process, thereby achieving the purpose of pre-regulating the condensate water, reducing the impact of the sudden increase or decrease in condensate water flow during deep peak regulation on the condensate water pH, and improving the stability of the condensate water system operation.

[0075] Example 2

[0076] In one embodiment, a method for controlling the dosing of ammonia water into condensate water obtains a pH value detected at a sampling point, combines it with a preset pH target value, and calculates the output frequency of a dosing pump inverter, including:

[0077] Determine the calculation formula for the inverter output frequency of the dosing pump;

[0078] Update the correction factor in the calculation formula based on the current pH value and the pH target value;

[0079] The update formula is:

[0080] Where A is the correction coefficient after update, A1 is the correction coefficient before update, pH1 is the target pH value of condensate water, and pH2 is the current pH value of condensate water;

[0081] Obtain the condensate flow rate and conductivity detected at the sampling point, the pH target value, the flow rate and stroke of the dosing pump, the updated correction coefficient, and calculate the frequency of the dosing pump;

[0082] The calculation formula is:

[0083]

[0084] Among them, A is the updated correction coefficient, HZ is the target output frequency of the dosing pump inverter, pH1 is the pH target value, Q1 is the condensate flow rate, Q2 is the dosing pump flow rate, and J is the stroke of the dosing pump.

[0085] In this embodiment, the initial value of the correction coefficient is 1.

[0086] Example 3

[0087] In one embodiment, a method for controlling the dosing of ammonia water into condensate water obtains the conductivity detected at a sampling point and controls the frequency adjustment speed of a dosing pump based on the difference between the conductivity and a reference value, including:

[0088] Obtain all the conductivity of the condensed water detected within the set time period at the sampling point and calculate the effective value of all the conductivity. The calculation formula is:

[0089]

[0090] Among them, c is the effective value of all conductivity within the set time period of the sampling point, n is the number of detections within the set time of the sampling point, C i is the conductivity value of each test;

[0091] The difference between the effective value of the conductivity and the preset reference value is calculated, and the adjustment speed of the dosing pump frequency is adjusted according to the size of the difference; wherein, the larger the difference, the faster the adjustment speed.

[0092] In this embodiment, the set time period is the cycle time for adjusting the pH value of the condensate;

[0093] The adjustment speed of the dosing pump frequency is adjusted according to the size of the difference, including:

[0094] According to the size of the difference A, adjust the frequency adjustment speed B of the dosing pump.

[0095] Preset difference matrix A0, set A0(A1, A2, A3, A4), where A1 is the first preset difference, A2 is the second preset difference, A3 is the third preset difference, A4 is the fourth preset difference, and A1<A2<A3<A4;

[0096] A regulating coefficient matrix C0 for regulating the regulating speed B is preset, and C0(C1, C2, C3) is set, where C1 is a first preset regulating coefficient, C2 is a second preset regulating coefficient, C3 is a third preset regulating coefficient, and 1<C1<C2<C3<1.2;

[0097] According to the relationship between the difference value A and the data of the preset difference matrix A0, the adjustment coefficient of the adjustment speed B of the dosing pump frequency is determined, and the current adjustment speed B is adjusted:

[0098] When A<A1, there is no need to adjust the adjustment speed B of the dosing pump frequency;

[0099] When A1≤A<A2, the first preset adjustment coefficient C1 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjustment speed after adjustment is B*C1;

[0100] When A2≤A<A3, the second preset adjustment coefficient C2 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjustment speed after adjustment is B*C2;

[0101] When A3≤A<A4, the third preset adjustment coefficient C3 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C3.

[0102] Before calculating the effective value of conductivity, the following are included:

[0103] Sort all conductivities by numerical value and obtain the median value of all conductivities;

[0104] All conductivity data were divided into ten equal parts; based on the median value, the conductivity of the two parts greater than the median value was taken as the upper value, and the conductivity of the two parts less than the median value was taken as the lower value;

[0105] The upper limit value and the lower limit value are calculated based on the upper value and the lower value, wherein the upper limit value and the lower limit value are calculated by the following formulas: Q3 = Q1 + 1.5 * (Q1 - Q2), Q4 = Q2 - 1.5 * (Q1 - Q2); wherein Q1 is the upper value, Q2 is the lower value, Q3 is the upper limit value, and Q4 is the lower limit value;

[0106] Clear all conductivity data that are greater than the upper limit value Q3 or less than the lower limit value Q4.

[0107] The beneficial effects of the above embodiment are: after eliminating all abnormalities in the conductivity data and calculating the effective value, the stability of the data calculation is improved. The adjustment speed is adjusted according to the effective value, which reduces the occurrence of excessively fast or excessively slow addition of ammonia water.

[0108] Example 4

[0109] In one embodiment, a method for controlling the dosing of ammonia in condensate water re-executes step 1 when a pH change is detected at a sampling point, including:

[0110] Preset the normal range of condensate pH value, obtain the current pH value of condensate detected at the collection point, compare and analyze the current pH value with the normal pH range, and adjust the time to perform step 1 again;

[0111] A preset adjustment period for the pH value of the condensate water is set, and a detection period and an acceleration period are set within the adjustment period; wherein the detection period is at the beginning of the adjustment period, the acceleration period is at the end of the adjustment period, and the detection period and the acceleration period do not overlap;

[0112] After adjusting the frequency of the dosing pump, start timing the adjustment cycle;

[0113] If the current pH value is within the normal pH range, the timing of the adjustment cycle proceeds normally;

[0114] When the timing of the adjustment cycle does not reach the acceleration time period:

[0115] If the current pH value exceeds the normal pH range, the timing of the adjustment cycle is adjusted to the beginning of the acceleration period;

[0116] When the timing of the adjustment cycle is within the acceleration time period:

[0117] If the current pH value exceeds the normal pH range, the timing of the adjustment cycle is adjusted to the end of the adjustment cycle, and step 1 is performed again.

[0118] In this embodiment, the normal range of pH is 9.2-9.6;

[0119] In this embodiment, after each adjustment cycle ends, steps 1 to 3 in embodiment 1 are executed.

[0120] The beneficial effects of the above embodiment are: adjusting the adjustment period according to the real-time change of the pH value, avoiding large fluctuations in the pH value of the condensate water due to untimely adjustment, and improving the stability of the condensate water system operation.

[0121] Example 5

[0122] In one embodiment, a method for controlling ammonia dosing of condensate water pre-adjusts a target pH value according to load changes of a steam turbine unit, comprising:

[0123] A load change threshold is preset, a load prediction change curve of the steam turbine unit is obtained, and the load change time is determined according to the load change curve and the load change threshold; wherein the judgment time interval of the load change threshold is a preset unit time length;

[0124] Determine the predicted load after a unit time period when the load changes based on the load change time;

[0125] Obtain historical data of the steam turbine unit, match it with the predicted load, and extract the condensate flow rate of the outlet main pipe of the polishing system corresponding to the predicted load;

[0126] Pre-adjust the pH target value based on the current condensate flow rate and the predicted condensate flow rate; if the current condensate flow rate is less than the predicted condensate flow rate, the pH target value is lowered; if the current condensate flow rate is greater than the predicted condensate flow rate, the pH target value is increased;

[0127] After the turbine unit load remains stable, the pH target value is restored to the normal value.

[0128] In the above embodiment, the pH target value is increased and adjusted by the following process:

[0129] Calculate the flow difference D between the current condensate flow and the predicted condensate flow, and adjust the pH target value F according to the flow difference D.

[0130] Preset flow difference matrix D0, set D0 (D1, D2, D3, D4), where D1 is the first preset flow difference, D2 is the second preset flow difference, D3 is the third preset flow difference, D4 ​​is the fourth preset flow difference, and D1 < D2 < D3 < D4;

[0131] Preset adjustment coefficient matrix E0, set E0(E1, E2, E3), where E1 is the first preset adjustment coefficient, E2 is the second preset adjustment coefficient, E3 is the third preset adjustment coefficient, and 1<E1<E2<E3<1.2;

[0132] According to the relationship between the difference D and the data in the preset difference matrix D0, the adjustment coefficient is determined to adjust the pH target value F:

[0133] When D<D1, there is no need to adjust the pH target value F;

[0134] When D1≤D<D2, the first preset adjustment coefficient E1 is selected to adjust the pH target value F, and the adjusted pH target value F is F*E1;

[0135] When D2≤D<D3, the second preset adjustment coefficient E2 is selected to adjust the pH target value F, and the adjusted pH target value F is F*E2;

[0136] When D3≤D<D4, the third preset adjustment coefficient E3 is selected to adjust the pH target value F, and the adjusted pH target value F is F*E3.

[0137] The beneficial effects of the above embodiment are: pre-adjusting the pH target value to cope with the change in condensate flow during deep peak regulation of the thermal power plant, thereby improving the stability of the condensate system operation.

[0138] It should be noted that the above embodiments are only exemplified by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps and are not to be regarded as improper limitations of the present invention.

[0139] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0140] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0141] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the claims and their equivalents, and to enable those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the dosing of ammonia water into condensate water, characterized in that: include: A dosing point and a sampling point are arranged on the outlet main pipe of the condensate polishing system; wherein the sampling point is arranged after the dosing point; Step 1: Obtain the pH value detected at the sampling point, and calculate the output frequency of the dosing pump inverter in combination with a preset pH target value; Step 2: obtaining the conductivity detected at the sampling point, and controlling the adjustment speed of the dosing pump frequency according to the difference between the conductivity and a reference value; Step 3: controlling the operation of the dosing pump according to the output frequency and the adjustment speed, and re-executing step 1 when a pH value change is detected at the sampling point to form a closed-loop control; In the step 1, the pH target value is pre-adjusted according to the load change of the steam turbine unit.

2. The method for controlling the dosing of ammonia water into condensate water according to claim 1, characterized in that: The step of obtaining the pH value detected at the sampling point and calculating the output frequency of the dosing pump inverter in combination with a preset pH target value includes: Determine the calculation formula for the inverter output frequency of the dosing pump; updating a correction factor in a calculation formula according to the current pH value and the pH target value; The update formula is: Where A is the correction coefficient after update, A1 is the correction coefficient before update, pH1 is the target pH value of condensate water, and pH2 is the current pH value of condensate water; Obtaining the condensate flow rate and conductivity detected at the sampling point, the pH target value, the flow rate and stroke of the dosing pump, and the updated correction coefficient, and calculating the frequency of the dosing pump; The calculation formula is: Among them, A is the updated correction coefficient, HZ is the target output frequency of the dosing pump inverter, pH1 is the pH target value, Q1 is the condensate flow rate, Q2 is the dosing pump flow rate, and J is the stroke of the dosing pump.

3. The method for controlling the dosing of ammonia water into condensate water according to claim 1, wherein: The step of obtaining the conductivity detected at the sampling point and controlling the adjustment speed of the dosing pump frequency according to the difference between the conductivity and a reference value includes: Obtain all the conductivity of the condensed water detected within the set time period of the sampling point, and calculate the effective value of all the conductivities. The calculation formula is: Wherein, c is the effective value of all conductivity within the set time period of the sampling point, n is the number of detections within the set time period of the sampling point, C i is the conductivity value of each test; The difference between the effective value of the conductivity and the preset reference value is calculated, and the adjustment speed of the dosing pump frequency is adjusted according to the size of the difference; wherein, the larger the difference, the faster the adjustment speed.

4. The method for controlling the dosing of ammonia water into condensate water according to claim 3, characterized in that: The adjusting speed of the dosing pump frequency according to the size of the difference includes: According to the size of the difference A, the adjustment speed B of the dosing pump frequency is adjusted. Preset difference matrix A0, set A0(A1, A2, A3, A4), where A1 is the first preset difference, A2 is the second preset difference, A3 is the third preset difference, A4 is the fourth preset difference, and A1<A2<A3<A4; A regulating coefficient matrix C0 for regulating the regulating speed B is preset, and C0(C1, C2, C3) is set, where C1 is a first preset regulating coefficient, C2 is a second preset regulating coefficient, C3 is a third preset regulating coefficient, and 1<C1<C2<C3<1.2; According to the relationship between the difference value A and the data of the preset difference matrix A0, the adjustment coefficient of the adjustment speed B of the dosing pump frequency is determined, and the current adjustment speed B is adjusted: When A<A1, there is no need to adjust the adjustment speed B of the dosing pump frequency; When A1≤A<A2, the first preset adjustment coefficient C1 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C1; When A2≤A<A3, the second preset adjustment coefficient C2 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C2; When A3≤A<A4, the third preset adjustment coefficient C3 is selected to adjust the adjustment speed B of the dosing pump frequency, and the adjusted adjustment speed is B*C3.

5. The method for controlling the dosing of ammonia water into condensate water according to claim 3, characterized in that: Before calculating the effective value of conductivity, the method includes: Sort all conductivities by numerical value and obtain the median value of all conductivities; Divide all conductivity data into ten equal parts; based on the median value, take the conductivity of the two parts greater than the median value as the upper value, and take the conductivity of the two parts less than the median value as the lower value; An upper limit value and a lower limit value are calculated based on the upper value and the lower value, wherein the upper limit value and the lower limit value are calculated by the following formulas: Q3=Q1+1.5*(Q1-Q2), Q4=Q2-1.5*(Q1-Q2); wherein Q1 is the upper value, Q2 is the lower value, Q3 is the upper limit value, and Q4 is the lower limit value; In all conductivity data, data that is greater than the upper limit value Q3 or less than the lower limit value Q4 is deleted.

6. The method for controlling the dosing of ammonia water into condensate water according to claim 1, characterized in that: When a pH value change is detected at the sampling point, re-execution of step 1 includes: Preset a normal range of condensate pH value, obtain the current pH value of the condensate detected at the sampling point, compare and analyze the current pH value with the normal pH range, and adjust the time for re-performing step 1; A condensate pH value adjustment cycle is preset, and a detection period and an acceleration period are set within the adjustment cycle; wherein the detection period is at the beginning of the adjustment cycle, the acceleration period is at the end of the adjustment cycle, and the detection period and the acceleration period do not overlap; After the frequency of the dosing pump is adjusted, the timing of the adjustment cycle is started; If the current pH value is within the normal pH range, the timing of the adjustment cycle proceeds normally; When the timing of the adjustment cycle does not reach the acceleration time period: If the current pH value exceeds the normal pH range, adjusting the timing of the adjustment period to the beginning of the acceleration period; When the timing of the adjustment cycle is within the acceleration time period: If the current pH value exceeds the normal pH value range, the timing of the adjustment period is adjusted to the end of the adjustment period, and step 1 is performed again.

7. The method for controlling the dosing of ammonia water into condensate water according to claim 1, characterized in that: The pre-adjusting of the pH target value according to the load change of the steam turbine unit includes: A load change threshold is preset, a load prediction change curve of the steam turbine unit is obtained, and the load change time is determined according to the load change curve and the load change threshold; wherein the judgment time interval of the load change threshold is a preset unit time length; Determine the predicted load after the unit time period has elapsed when the load changes according to the load change time; Obtain historical data of the steam turbine unit, match it according to the predicted load, and extract the condensate flow rate of the outlet main pipe of the fine treatment system corresponding to the predicted load; Pre-adjusting the pH target value based on the current condensate flow rate and the predicted condensate flow rate; if the current condensate flow rate is less than the predicted condensate flow rate, lowering the pH target value; if the current condensate flow rate is greater than the predicted condensate flow rate, raising the pH target value; After the load of the steam turbine unit remains stable, the pH target value is restored to a normal value.

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