Circulating water system and control method for adjusting discharge capacity of circulating water system

Abstract

The invention provides a circulating water system and a control method for adjusting the discharge capacity of the system, and relates to the technical field of circulating water systems.The circulating water system comprises a water quality analyzer, an adjusting valve and a control unit, and the control method comprises the following steps that S1, the circulating water quantity (Qr), the circulating water feed / return water temperature and the real-time conductivity of circulating water are obtained in real time; s2, based on the circulating water volume, the circulating water feed / return water temperature difference () and the evaporation loss coefficient (k), the evaporation water volume (Qe) of the system is calculated; s3, based on the evaporation water quantity (Qe) and a preset concentration multiple (N), calculating a theoretical sewage discharge water quantity (Qb) of the system; s4, the control unit generates a control signal according to the theoretical sewage discharge amount (Qb) and adjusts the opening degree of the adjusting valve; according to the method, it can be guaranteed that the concentration multiple of the circulating water system is stable, and scaling caused by the too high concentration multiple and water resource waste caused by the too low concentration multiple are avoided.

Description

Technical Field

[0001] This invention relates to the field of circulating water system technology, and more specifically to a circulating water system and a control method for adjusting the sewage discharge of the system. Background Technology

[0002] Currently, the control of wastewater discharge in indirect cooling open-loop circulating water systems is carried out in accordance with the requirements of GB / T50050-2017 "Design Code for Industrial Circulating Cooling Water Treatment". During this process, process technicians calculate the wastewater discharge volume based on the analysis results of the influent and circulating water quality and the designed concentration ratio, and adjust the wastewater discharge regulating valve accordingly. However, because the water quality analysis is conducted periodically and lacks timeliness, fluctuations in the circulating water concentration ratio may occur, thus affecting the operation of the circulating water system. Summary of the Invention

[0003] This invention addresses the problem in current intermittent open-loop circulating water systems where water quality analysis is performed periodically, lacking timeliness and causing fluctuations in the concentration ratio of the circulating water, thus affecting the operation of the circulating water system. It provides a circulating water system and a control method for adjusting the system's wastewater discharge, ensuring a stable concentration ratio, preventing scaling due to excessively high concentration ratios, and avoiding water waste caused by excessively low concentration ratios.

[0004] The technical solution adopted in this invention is:

[0005] A method for controlling the discharge volume of a circulating water system is provided, including a water quality analyzer for detecting the conductivity of circulating water, a regulating valve installed on the discharge pipeline, and a control unit. The control method includes the following steps: S1, real-time acquisition of circulating water volume (Q) r S1) Circulating water supply temperature, circulating water return temperature, and real-time conductivity of circulating water; S2) Based on the circulating water volume, the temperature difference between the circulating water supply temperature and the return temperature ( ) and the evaporation loss coefficient (k), to calculate the system's evaporation water volume (Q) e S3, based on evaporation rate (Q) e ) and the preset concentration factor (N), calculate the theoretical wastewater discharge volume (Q) of the system. b S4, the control unit calculates the theoretical wastewater discharge volume (Q) b The system generates a control signal and adjusts the opening of the regulating valve; it dynamically determines the value of the evaporation loss coefficient (k) based on the real-time conductivity.

[0006] Optionally, the steps for dynamically determining the value of the evaporation loss coefficient (k) based on real-time conductivity include: S1.1, presetting multiple conductivity value ranges, each range corresponding to a specific evaporation loss coefficient (k) value; S1.2, matching the real-time acquired conductivity with the conductivity value ranges to select the corresponding evaporation loss coefficient (k) value.

[0007] Optionally, the higher the conductivity value, the larger the corresponding evaporation loss coefficient (k) value.

[0008] Optionally, in step S4, the control unit determines the theoretical wastewater discharge volume (Q) based on the wastewater discharge volume. b The steps for generating control signals include: S4.1, calculating the theoretical wastewater discharge volume (Q). b S4.2 ...

[0009] Optionally, a parameter acquisition module is used to acquire circulating water volume, circulating water supply temperature, circulating water return temperature, and circulating water conductivity in real time; a circulating water system includes:

[0010] The sewage discharge execution module is used to control the opening and closing status of the sewage discharge pipeline; the control unit is connected to the parameter acquisition module and the sewage discharge execution module respectively, and calculates based on the real-time collected circulating water volume, circulating water supply temperature, circulating water return temperature and circulating water conductivity value, and controls the sewage discharge execution module to discharge sewage; the control unit is configured to execute any of the aforementioned sewage discharge control methods.

[0011] Optionally, the parameter acquisition module includes a flow sensor, which is used to acquire the circulating water volume (Q) in the circulating water pipe in real time. r Temperature sensor, used to acquire real-time temperature of circulating water supply and return in the circulating water pipeline; water quality analyzer, used to acquire real-time conductivity of circulating water in the circulating water pipeline.

[0012] Optionally, the sewage discharge execution module includes a regulating valve located on the sewage discharge pipeline for regulating the sewage discharge volume of the sewage discharge pipeline.

[0013] Optionally, the control unit is a programmable logic controller (PLC) or a distributed control system (DCS).

[0014] The beneficial effects of this invention are:

[0015] Currently, the evaporation coefficient is determined according to the requirements of GB / T50050-2017 "Design Code for Industrial Circulating Cooling Water Treatment". The evaporation coefficient is taken as the local room temperature. The evaporation coefficient is selected based on the temperature. In actual operation, due to the influence of different seasons, the temperature deviation is large, while the temperature difference within the same season is small. In order to more accurately control the sewage discharge of circulating water, this invention determines the value of the evaporation coefficient based on the conductivity of the circulating water makeup water and the conductivity of the circulating water control range. This can more accurately control the sewage discharge, making the circulating water system more stable and avoiding scaling due to excessive concentration ratio or water waste due to excessively low concentration ratio. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for controlling the wastewater discharge of a circulating water system disclosed in this embodiment. Figure 1 ;

[0018] Figure 2 This is a flowchart illustrating a method for controlling the wastewater discharge of a circulating water system disclosed in this embodiment. Figure 2 ;

[0019] Figure 3 This is a flowchart illustrating a method for controlling the wastewater discharge of a circulating water system disclosed in this embodiment. Figure 3 ;

[0020] Figure 4 This is a schematic diagram of a circulating water system disclosed in this embodiment. Detailed Implementation

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0023] The embodiments of the invention will now be described in detail with reference to the accompanying drawings.

[0024] Example

[0025] Please see Figure 1-4 As shown, this embodiment discloses a method for controlling the discharge volume of a circulating water system, including a water quality analyzer for detecting the conductivity of circulating water, a regulating valve installed on the discharge pipeline, and a control unit. The control method includes the following steps: S1, real-time acquisition of circulating water volume (Q) r S1) Circulating water supply temperature, circulating water return temperature, and real-time conductivity of circulating water; S2) Based on the circulating water volume, the temperature difference between the circulating water supply temperature and the return temperature ( ) and the evaporation loss coefficient (k), to calculate the system's evaporation water volume (Q) e S3, based on evaporation rate (Q) e ) and the preset concentration factor (N), calculate the theoretical wastewater discharge volume (Q) of the system. b S4, The control unit generates a control signal based on the theoretical wastewater discharge volume (Qb) and adjusts the opening of the regulating valve; it dynamically determines the value of the evaporation loss coefficient (k) based on the real-time conductivity.

[0026] Furthermore, the above-mentioned steps for dynamically determining the evaporation loss coefficient (k) based on real-time conductivity include: S1.1, presetting multiple conductivity value ranges, each range corresponding to a specific evaporation loss coefficient (k) value; S1.2, matching the real-time acquired conductivity with the conductivity value ranges to select the corresponding evaporation loss coefficient (k) value.

[0027] Specifically, in actual operation, the determined conductivity can be mapped to multiple pre-set conductivity value ranges to obtain the evaporation loss coefficient k value within the corresponding conductivity value range, so as to quickly calculate the amount of sewage discharged.

[0028] Furthermore, the higher the conductivity value in the above range, the larger the corresponding evaporation loss coefficient (k) value, that is, there is a positive correlation between conductivity and the value of k.

[0029] Furthermore, in step S4, the control unit determines the theoretical wastewater discharge volume (Q) based on... b The steps for generating control signals include: S4.1, calculating the theoretical wastewater discharge volume (Q). bS4.2 ...

[0030] Specifically, the control unit calculates the theoretical wastewater discharge volume (Q). b ), and based on the theoretical wastewater discharge volume (Q) b This is used to adjust the opening of the regulating valve, thereby making the sewage discharge more precise and the circulating water system more stable.

[0031] According to GB / T50050-2017 "Design Code for Industrial Circulating Cooling Water Treatment", the design concentration ratio for indirect cooling open circulating water systems should not be less than 5.0, and should not be less than 3.0. The concentration ratio can be calculated using the following formula:

[0032] ,

[0033] In the formula:

[0034] N – Concentration factor;

[0035] Q m —Replenish water volume;

[0036] Q b — Wastewater discharge volume;

[0037] Q w —Water loss due to wind (negligible).

[0038] ,

[0039] In the formula: Qe — amount of water evaporated.

[0040] ,

[0041] Where: k—evaporation loss coefficient (1 / ℃); Δt—temperature difference between the inlet and outlet of the circulating cooling water in the cooling tower;

[0042] Qr — Circulating cooling water volume.

[0043] Atmospheric temperature entering the tower -10 0 10 20 30 40 K（1 / ℃） 0.0008 0.0010 0.0012 0.0014 0.0015 0.0016

[0044] Wastewater discharge volume calculation:

[0045] ,

[0046] Evaporation calculation: Circulation rate * Circulation water temperature difference (return water temperature - feed water temperature) * Evaporation coefficient.

[0047] The formula for calculating wastewater discharge is: Evaporation rate / (Concentration factor - 1).

[0048] The aforementioned circulating water system includes a parameter acquisition module for real-time acquisition of circulating water volume, circulating water supply temperature, circulating water return temperature, and circulating water conductivity; a sewage discharge execution module for controlling the opening and closing status of the sewage discharge pipeline; and a control unit that is communicatively connected to both the parameter acquisition module and the sewage discharge execution module, and calculates based on the real-time acquired circulating water volume, circulating water supply temperature, circulating water return temperature, and circulating water conductivity values ​​to control the sewage discharge execution module to discharge sewage; the control unit is configured to execute any of the aforementioned sewage discharge control methods.

[0049] Furthermore, the parameter acquisition module includes a flow sensor, which is used to acquire the circulating water volume (Q) in the circulating water pipeline in real time. r Temperature sensor, used to acquire real-time temperature of circulating water supply and return in the circulating water pipeline; water quality analyzer, used to acquire real-time conductivity of circulating water in the circulating water pipeline.

[0050] The sewage discharge execution module includes a regulating valve installed on the sewage discharge pipeline, which is used to regulate the sewage discharge volume of the sewage discharge pipeline.

[0051] Furthermore, the control unit is a programmable logic controller (PLC) or a distributed control system (DCS).

[0052] Specifically, in actual operation, the circulating water volume (Q) is obtained through flow sensors, temperature sensors, and water quality analyzers. r After obtaining the relevant values ​​such as circulating water supply temperature, circulating water temperature, and conductivity, the control unit can perform calculations. Specifically, it selects the evaporation coefficient based on the conductivity and finally calculates the theoretical sewage discharge volume. Then, the control unit controls the opening of the regulating valve on the sewage discharge pipeline according to the calculated theoretical sewage discharge volume, making the sewage discharge volume more accurate.

[0053] The following are specific examples:

[0054] The conductivity of the circulating water makeup water in a certain unit during the summer is 300 μS / cm. The concentration factor of the circulating water system is controlled at 5 times, that is, the conductivity of the circulating water system is controlled at 1500 μS / cm.

[0055] Evaporation coefficient values ​​(base value 0.0014 for summer, 0.0012 for spring and autumn, and 0.0010 for winter): For conductivity ≤ 1500 μS / cm, the evaporation coefficient X is 0.0014.

[0056] Electrical conductivity 1500-1530 μS / cm, evaporation coefficient X is 0.00145;

[0057] Electrical conductivity 1530-1550 μS / cm, evaporation coefficient X is 0.0015;

[0058] Electrical conductivity 1550-1580 μS / cm, evaporation coefficient X is 0.00155;

[0059] Electrical conductivity ≥1580 μS / cm, evaporation coefficient X is 0.0016.

[0060] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Without conflict, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the discharge volume of a circulating water system, comprising a water quality analyzer for detecting the conductivity of the circulating water, a regulating valve installed on the discharge pipeline, and a control unit, the control method comprising the following steps: S1. Real-time acquisition of circulating water volume (Q) r S1) The circulating water supply temperature, circulating water return temperature, and real-time conductivity of the circulating water; S2) Based on the circulating water volume, the temperature difference between the circulating water supply temperature and the return temperature ( ) and the evaporation loss coefficient (k), to calculate the system's evaporation volume (Q) e S3, based on the evaporation water volume (Q) e ) and the preset concentration factor (N), calculate the theoretical wastewater discharge volume (Q) of the system. b S4, the control unit, based on the theoretical wastewater discharge volume (Q) b The control signal is generated and the opening of the regulating valve is adjusted; characterized in that the value of the evaporation loss coefficient (k) is dynamically determined according to the real-time conductivity.

2. The method for controlling the discharge volume of a circulating water system according to claim 1, characterized in that, The step of dynamically determining the value of the evaporation loss coefficient (k) based on the real-time conductivity includes: S1.1, presetting multiple conductivity value ranges, each range corresponding to a specific evaporation loss coefficient (k) value; S1.2, matching the real-time acquired conductivity with the conductivity value ranges to select the corresponding evaporation loss coefficient (k) value.

3. The method for controlling the discharge volume of a circulating water system according to claim 2, characterized in that, The higher the conductivity value, the greater the corresponding evaporation loss coefficient (k) value.

4. The method for controlling the discharge volume of a circulating water system according to claim 1, characterized in that, In step S4, the control unit calculates the theoretical wastewater discharge volume (Q) based on the data. b The steps for generating control signals include: S4.1, calculating the theoretical wastewater discharge volume (Q). b S4.

2. The average value within a preset time period; S4.

3. Generate the control signal based on the average value to smooth the operation of the regulating valve.

5. A circulating water system, comprising: A parameter acquisition module is used to collect circulating water volume, circulating water supply temperature, circulating water return temperature, and circulating water conductivity in real time; a sewage discharge execution module is used to control the opening and closing status of the sewage discharge pipeline; a control unit is communicatively connected to the parameter acquisition module and the sewage discharge execution module respectively, and calculates based on the real-time collected circulating water volume, circulating water supply temperature, circulating water return temperature, and circulating water conductivity values, and then controls the sewage discharge execution module to discharge sewage; characterized in that the control unit is configured to execute the sewage discharge control method as described in any one of claims 1-4.

6. The circulating water system according to claim 5, characterized in that, The parameter acquisition module includes a flow sensor, which is used to acquire the circulating water volume (Q) in the circulating water pipeline in real time. r Temperature sensor, used to acquire real-time temperature of circulating water supply and return in the circulating water pipeline; water quality analyzer, used to acquire real-time conductivity of circulating water in the circulating water pipeline.

7. The circulating water system according to claim 5, characterized in that, The sewage discharge execution module includes a regulating valve installed on the sewage discharge pipeline for regulating the sewage discharge volume of the sewage discharge pipeline.

8. The circulating water system according to claim 5, characterized in that, The control unit is a programmable logic controller (PLC) or a distributed control system (DCS).

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