Electrochemical treatment method for dechlorination and hardness removal of circulating water

Abstract

The invention relates to the technical field of industrial circulating water treatment, in particular to an electrochemical treatment method for dechlorination and hardness removal of circulating water, which comprises the following steps: pretreating the circulating water; introducing the pretreated circulating water into a first-stage electrode reactor, and determining the first-stage current concentration and the first-stage voltage in the electrochemical treatment process in the first-stage electrode reactor; determining a current concentration adjusting mode and a voltage adjusting mode of the primary electrode reactor according to a water flow velocity difference between a first electrode plate and a second electrode plate in the primary electrode reactor; judging whether the electrochemical reaction in the primary electrode reactor meets a preset standard or not, and if yes, introducing circulating water in the primary electrode reactor into a secondary electrode reactor; determining secondary current concentration and secondary voltage in the electrochemical treatment process in the secondary electrode reactor; and judging whether the electrochemical reaction in the secondary electrode reactor meets a preset standard or not. The dechlorination and hardness removal reaction speed and the removal rate can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of industrial circulating water treatment, and in particular to an electrochemical treatment method for removing chlorine and hardness from circulating water. Background Art

[0002] As the concentration of industrial circulating water increases, the hardness and chloride ions of circulating water also increase. Sometimes, circulating water replacement is necessary to improve the quality of circulating water, resulting in a large amount of water resource loss. The discharge of saline wastewater, especially industrial high-salt wastewater, also leads to salinization of river soil. At present, the treatment of high-concentration saline wastewater generally adopts the process of membrane concentration and then evaporation and crystallization. However, there are problems such as high investment and operating costs that make it difficult to popularize and apply. When using membrane or evaporation methods for treatment, the equipment will be severely scaled during operation, making it difficult to operate the equipment.

[0003] The ultra-calcium-aluminum precipitation method can effectively remove chlorine. The reaction is relatively complex. The main reaction mechanism is that calcium salt and aluminum salt react to generate Ca4Al2(OH) 14 , chloride ion and Ca4Al2(OH) 14 OH - Ion exchange occurs, forming calcium aluminum chlorofluorite salt precipitation Ca4Al2Cl2(OH) 12 However, excessive aluminum salt and alkaline environment will cause side reactions during the reaction, which will reduce the efficiency of chloride ion removal. Therefore, the reaction process should be controlled in the process of removing chloride ions to achieve a higher chlorine removal effect. In actual engineering applications, the Cl in water - The constant fluctuation of calcium oxide and aluminate, the long reaction time, and the slow feedback make it difficult to control accurately in practice. Therefore, although domestic and foreign researchers have reported more and more research on the removal of chloride ions by ultra-calcium aluminum precipitation, and have achieved certain dechlorination effects, they are basically based on laboratory basic research and development stages, and have not been applied in practice, and there is no mention of how to increase the reaction speed and achieve the reaction effect. At present, there is an urgent need for a method that can increase the reaction speed and removal rate of dechlorination and hardness removal. Summary of the invention

[0004] To this end, the present invention provides an electrochemical treatment method for removing chlorine and hardness from circulating water, so as to overcome the problems in the prior art that it is difficult to increase the reaction speed of the chlorine and hardness removal, as well as the low removal rate.

[0005] To achieve the above object, the present invention provides an electrochemical treatment method for removing chlorine and hardness from circulating water, comprising:

[0006] Step S1, pre-treating the circulating water, and detecting the chloride ion concentration and conductivity of the pre-treated circulating water;

[0007] Step S2, passing the pretreated circulating water into a primary electrode reactor, and determining a primary current concentration and a primary voltage of an electrochemical treatment process in the primary electrode reactor according to the chloride ion concentration and the conductivity;

[0008] Step S3, determining a current concentration adjustment method and a voltage adjustment method for the electrochemical treatment process in the primary electrode reactor according to a water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor;

[0009] Step S4, detecting the pH before and after the electrode plate flow channel of the primary electrode reactor after the first reaction time to determine whether the electrochemical reaction inside the primary electrode reactor meets the preset standard, and if so, passing the circulating water inside the primary electrode reactor into the secondary electrode reactor;

[0010] Step S5, determining the secondary current concentration and the secondary voltage of the electrochemical treatment process in the secondary electrode reactor according to the pH before and after the electrode plate flow channel of the primary electrode reactor;

[0011] Step S6, detecting the pH value before and after the electrode plate flow channel of the secondary electrode reactor after the second reaction time to determine whether the electrochemical reaction inside the secondary electrode reactor meets the preset standard. If not, determining the current concentration adjustment amount and the voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor according to the pH value before and after the electrode plate flow channel of the secondary electrode reactor.

[0012] Furthermore, in the step S2, it includes:

[0013] Step S21, determining a first correlation coefficient according to the chloride ion concentration and the conductivity;

[0014] Step S22, determining the primary current concentration according to the first correlation coefficient and the standard current concentration, and determining the primary voltage according to the first correlation coefficient and the standard voltage.

[0015] Furthermore, in the step S3, it includes:

[0016] If the water flow rate difference between the first electrode plate and the second electrode plate in the primary electrode reactor is greater than the first preset flow rate difference, reducing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor;

[0017] If the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor is less than or equal to the second preset flow rate difference, the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor are increased.

[0018] Furthermore, in the step S3, it includes:

[0019] Determining a reduction range of current concentration / voltage according to a water flow rate difference between a first electrode plate and a second electrode plate in the primary electrode reactor and a first preset flow rate difference;

[0020] The increase range of the current concentration / voltage is determined according to the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor and the second preset flow rate difference.

[0021] Furthermore, in the step S4, it includes:

[0022] If the pH value after the plate flow channel of the primary electrode reactor is less than the first preset pH value, it is determined that the electrochemical reaction inside the primary electrode reactor meets the preset standard;

[0023] If the pH value after the plate flow channel of the primary electrode reactor is greater than or equal to the first preset pH value, it is determined that the electrochemical reaction inside the primary electrode reactor does not meet the preset standard.

[0024] Furthermore, in the step S5, it includes:

[0025] Step S51, determining a second correlation coefficient according to the pH before and after the plate flow channel of the primary electrode reactor;

[0026] Step S52, determining the secondary current concentration according to the second correlation coefficient and the standard current concentration, and determining the secondary voltage according to the second correlation coefficient and the standard voltage.

[0027] Furthermore, in step S6, it includes:

[0028] If the pH value after the plate flow channel of the secondary electrode reactor is less than a second preset pH value, it is determined that the electrochemical reaction inside the secondary electrode reactor meets the preset standard;

[0029] If the pH value after the plate flow channel of the secondary electrode reactor is greater than or equal to the second preset pH value, it is determined that the electrochemical reaction inside the secondary electrode reactor does not meet the preset standard.

[0030] Furthermore, in step S6, it includes:

[0031] Determining the current concentration adjustment amount of the electrochemical treatment process in the secondary electrode reactor according to the difference in pH before and after the electrode plate flow channel of the secondary electrode reactor and the standard current concentration;

[0032] The voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor is determined according to the difference in pH before and after the electrode plate flow channel of the secondary electrode reactor and the standard voltage.

[0033] Furthermore, in the step S4, it also includes:

[0034] If the electrochemical reaction inside the primary electrode reactor does not meet the preset standard, a preset regulator is introduced into the primary electrode reactor.

[0035] Furthermore, the amount of the preset adjusting substance introduced is determined according to the difference between the pH value after the electrode plate flow channel of the primary electrode reactor and the first preset pH value.

[0036] Compared with the prior art, the beneficial effect of the present invention is that the present invention can improve the removal rate of chlorine and hardness removal of circulating water by setting a two-stage reactor to perform electrochemical treatment on circulating water. By determining the primary current concentration and primary voltage of the electrochemical treatment process in the primary electrode reactor according to the chloride ion concentration and the conductivity of the circulating water, and determining the current concentration adjustment method and voltage adjustment method of the electrochemical treatment process in the primary electrode reactor according to the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor, the circulating water is treated with the primary current concentration and primary voltage determined in this way, which can improve the reaction rate. The secondary current concentration and secondary voltage of the electrochemical treatment process in the secondary electrode reactor are determined according to the pH before and after the electrode plate flow channel of the primary electrode reactor, which can further improve the reaction rate. The pH before and after the electrode plate flow channel of the primary electrode reactor after the preset reaction time and the pH before and after the electrode plate flow channel of the secondary electrode reactor after the preset reaction time are judged, and subsequent operations are performed only after the judgment meets the preset standard, which can improve the removal rate.

[0037] Furthermore, the present invention determines the first correlation coefficient by detecting the chloride ion concentration and conductivity of the circulating water, and the primary current concentration and primary voltage determined thereby can increase the reaction rate of the electrochemical process in the primary electrode reactor.

[0038] Furthermore, the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor of the present invention is greater than the first preset flow rate difference, indicating that the electrochemical reaction inside the primary electrode reactor is uneven. By reducing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor, the uniformity of the electrochemical reaction can be improved by reducing the flow rate distribution on the electrode surface, thereby increasing the reaction rate of the electrochemical process; the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor is less than or equal to the second preset flow rate difference, indicating that the mass transfer efficiency is relatively low. By increasing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor, the electron transfer efficiency can be improved by increasing the flow rate distribution on the electrode surface, thereby increasing the reaction rate of the electrochemical process.

[0039] Furthermore, the present invention determines the second correlation coefficient by the pH before and after the plate flow channel of the primary electrode reactor, and the secondary current concentration and secondary voltage determined thereby can increase the reaction rate of the electrochemical process in the primary electrode reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a flow chart of an electrochemical treatment method for removing chlorine and hardness from circulating water according to an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of a process for determining a primary current concentration and a primary voltage according to an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of a process for determining a secondary current concentration and a secondary voltage according to an embodiment of the present invention;

[0043] Figure 4 A logic determination diagram for determining whether the electrochemical reaction inside the primary electrode reactor meets the preset standard according to an embodiment of the present invention;

[0044] Figure 5 A logic determination diagram for determining whether an electrochemical reaction inside a secondary electrode reactor meets a preset standard according to an embodiment of the present invention;

[0045] Figure 6 This is a process flow chart for removing chlorine and hardness from circulating water according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0048] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0049] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] The main reaction mechanism chemical equation of the embodiment of the present invention is as follows:

[0051] Reaction 1: 4Ca(OH)2+2Al(OH)3=Ca4Al2(OH) 14 ;

[0052] Reaction 2: Ca4Al2(OH) 14 +2Cl - =Ca4Al2Cl2(OH) 12 +2OH - ;

[0053] Reaction 3: 3Ca4Al2Cl2(OH) 12 +2Al(OH)4 - +4OH - =4Ca3Al2(OH) 12 +6Cl - ;

[0054] Reaction 4: 3Ca4Al2(OH) 14 +2Al(OH)4 - =4Ca3Al2(OH) 12 +2OH - ;

[0055] The first two reactions in the above four chemical equations are the core reactions for removing chloride ions from wastewater. Calcium salts react with aluminum salts to generate Ca4Al2(OH) 14 , chloride ion and Ca4Al2(OH) 14 OH - Ion exchange occurs, forming calcium aluminum chlorofluorite salt precipitation Ca4Al2Cl2(OH) 12 .

[0056] See also Figure 1 , Figure 4-Figure 6 As shown, Figure 1 This is a flow chart of an electrochemical treatment method for removing chlorine and hardness from circulating water according to an embodiment of the present invention; Figure 4A logic determination diagram for determining whether the electrochemical reaction inside the primary electrode reactor meets the preset standard according to an embodiment of the present invention; Figure 5 A logic determination diagram for determining whether an electrochemical reaction inside a secondary electrode reactor meets a preset standard according to an embodiment of the present invention; Figure 6 The present invention provides a process flow chart for removing chlorine and hardness from circulating water according to an embodiment of the present invention. The present invention provides an electrochemical treatment method for removing chlorine and hardness from circulating water, comprising:

[0057] Step S1, pre-treating the circulating water, and detecting the chloride ion concentration and conductivity of the pre-treated circulating water;

[0058] In practice, pretreatment includes side filtration. During the operation of the circulating water system, especially in the cooling water, there will be a large amount of suspended matter. Due to the entry of dust and debris in the air, some scale, rust, and microbial slime will fall off and disperse, making the water turbid. Since the solubility of various impurities in water is very small, it is easy to remove them by mechanical filtration. Bypass filtration through side filtration equipment can effectively remove impurities in the circulating water, which can not only prevent pipeline blockage, but also improve the reaction speed and removal rate of subsequent chlorine and hardness removal.

[0059] It is understandable that those skilled in the art know that any device and method in the prior art that can detect the chloride ion concentration and conductivity of circulating water falls within the protection scope of the present invention and will not be described in detail herein.

[0060] Step S2, passing the pretreated circulating water into a primary electrode reactor, and determining a primary current concentration and a primary voltage of an electrochemical treatment process in the primary electrode reactor according to the chloride ion concentration and the conductivity;

[0061] It can be understood that an electrode plate flow channel is arranged in the primary electrode reactor, and the distance between the electrode plates in the flow channel is 2cm to 4cm. The electrode plates of the primary reactor are divided into Ⅰ1 unit insoluble electrode plates and Ⅰ2 unit soluble electrode plates. The bipolar electrode of the Ⅰ1 unit insoluble electrode plate adopts titanium rod needle electrode or titanium mesh electrode, and the bipolar electrode of the Ⅰ2 unit soluble electrode can adopt aluminum powder mixed electrode.

[0062] It should be noted that the current concentration is the current passing through a unit cross-sectional area. For example, the current passing through a cross-sectional area of ​​2m 2 The current of the primary electrode reactor is 4A, so the current density corresponding to this cross section is 4 / 2 = 2A / m 2 .

[0063] In practice, by controlling the current concentration and voltage during the electrochemical treatment in the primary electrode reactor, that is, the primary current concentration and the primary voltage, the amount of calcium, aluminum ions and hydroxide ions produced by direct ionization of the electrolysis and dissolution electrodes can be accurately controlled, and the concentration of reactants can be increased through electric field voltage enrichment to accelerate the reaction rate.

[0064] See also Figure 2 As shown, it is a schematic diagram of a process for determining the primary current concentration and the primary voltage according to an embodiment of the present invention; specifically, in the step S2, it includes:

[0065] Step S21, determining a first correlation coefficient according to the chloride ion concentration and the conductivity;

[0066] Step S22, determining the primary current concentration according to the first correlation coefficient and the standard current concentration, and determining the primary voltage according to the first correlation coefficient and the standard voltage.

[0067] In implementation, the first intermediate value is determined according to the ratio of the chloride ion concentration to the standard chloride ion concentration, the second intermediate value is determined according to the ratio of the conductivity to the standard conductivity, and the first correlation coefficient is determined according to the product of the first intermediate value and the second intermediate value; the primary current concentration is determined according to the product of the first correlation coefficient and the standard current concentration, and the primary voltage is determined according to the product of the first correlation coefficient and the standard voltage.

[0068] It can be understood that there is a corresponding relationship between the standard chloride ion concentration, standard conductivity, standard current concentration, and standard voltage. The standard chloride ion concentration and standard conductivity are determined based on the average of the chloride ion concentration and conductivity of the circulating water detected during the electrochemical treatment process that has passed the qualification test in the historical data. The standard current concentration and standard voltage are determined based on the average of the current concentration and voltage of the circulating water with standard chloride ion concentration and standard conductivity that are in the forefront (top 3 to 5) in terms of removal rate and reaction rate during the electrochemical treatment process. The standard chloride ion concentration range is set at 50mg / L to 100mg / L, the standard conductivity range is set at 500μS / cm to 1000μS / cm, and the standard current concentration range is set at 60A / m 2 ~80A / m 2 The standard voltage range is set at 36V~60V.

[0069] In another specific embodiment, training samples can be generated based on the chloride ion concentration and conductivity of circulating water of each electrochemical treatment in historical data, corresponding sample labels can be generated based on the current concentration and voltage in the electrochemical process in the primary electrode reactor that has passed the qualification test, and the initial neural network model can be trained based on each training sample and the corresponding sample label to obtain a primary neural network model; the detected chloride ion concentration and the conductivity are input into the primary neural network model to obtain the primary current concentration and the primary voltage output by the primary neural network model.

[0070] The present invention determines the first correlation coefficient by detecting the chloride ion concentration and conductivity of the circulating water, and the primary current concentration and primary voltage determined thereby can improve the reaction speed of the electrochemical process in the primary electrode reactor.

[0071] Step S3, determining a current concentration adjustment method and a voltage adjustment method for the electrochemical treatment process in the primary electrode reactor according to a water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor;

[0072] Specifically, step S3 includes:

[0073] If the water flow rate difference between the first electrode plate and the second electrode plate in the primary electrode reactor is greater than the first preset flow rate difference, reducing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor;

[0074] If the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor is less than or equal to the second preset flow rate difference, the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor are increased.

[0075] Specifically, step S3 includes:

[0076] Determining a reduction range of current concentration / voltage according to a water flow rate difference between a first electrode plate and a second electrode plate in the primary electrode reactor and a first preset flow rate difference;

[0077] The increase range of the current concentration / voltage is determined according to the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor and the second preset flow rate difference.

[0078] In implementation, a third intermediate value is determined based on the difference between the water flow rate difference and the first preset flow rate difference, a fourth intermediate value is determined based on the ratio of the third intermediate value to the first preset flow rate difference, a reduction range of the current concentration of the electrochemical treatment process in the primary electrode reactor is determined based on the product of the fourth intermediate value and the primary current concentration, and a reduction range of the voltage of the electrochemical treatment process in the primary electrode reactor is determined based on the product of the fourth intermediate value and the primary voltage; a fifth intermediate value is determined based on the difference between the second preset flow rate difference and the water flow rate difference, a sixth intermediate value is determined based on the ratio of the fifth intermediate value to the second preset flow rate difference, an increase range of the current concentration of the electrochemical treatment process in the primary electrode reactor is determined based on the product of the sixth intermediate value and the primary current concentration, and an increase range of the voltage of the electrochemical treatment process in the primary electrode reactor is determined based on the product of the sixth intermediate value and the primary voltage.

[0079] It can be understood that the actual implementers can determine the first preset flow rate difference based on the actual situation or the average of the maximum values ​​of the water flow rate difference between the first electrode plate and the second electrode plate in the electrochemical process of the primary electrode reactor that has passed the qualification test in historical data, and determine the second preset flow rate difference based on the actual situation or the average of the minimum values ​​of the water flow rate difference between the first electrode plate and the second electrode plate in the electrochemical process of the primary electrode reactor that has passed the qualification test in historical data. Preferably, the value range of the first preset flow rate difference can be set to 0.5m / s~0.8m / s, and the value range of the second preset flow rate difference can be set to 0.01m / s~0.1m / s.

[0080] The water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor of the present invention is greater than the first preset flow rate difference, indicating that the electrochemical reaction inside the primary electrode reactor is uneven. By reducing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor, the flow rate distribution on the electrode surface can be reduced, and the amount of aluminum ions dissociated by the dissolved electrode can be reduced, thereby improving the uniformity of the electrochemical reaction; the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor is less than or equal to the second preset flow rate difference, indicating that the mass transfer efficiency is relatively low. By increasing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor, the electron transfer efficiency can be improved by increasing the flow rate distribution on the electrode surface, and the amount of aluminum ions dissociated by the dissolved electrode can be increased, thereby improving the reaction rate of the electrochemical process.

[0081] Step S4, detecting the pH before and after the electrode plate flow channel of the primary electrode reactor after the first reaction time to determine whether the electrochemical reaction inside the primary electrode reactor meets the preset standard, and if so, passing the circulating water inside the primary electrode reactor into the secondary electrode reactor;

[0082] It can be understood that the first reaction time starts from the time when the circulating water begins to flow into the primary electrode reactor. Preferably, the first reaction time is set in the range of 2 min to 5 min.

[0083] In implementation, the corresponding pH value can be determined based on the pH value of the liquid before and after the electrode plate flow channel of the primary electrode reactor / secondary electrode reactor.

[0084] It can be understood that an electrode plate flow channel is set in the secondary electrode reactor, and the distance between the electrode plates in the flow channel is 2cm to 4cm. The electrode plates of the secondary reactor are divided into Ⅱ1 unit insoluble electrode plates and Ⅱ2 unit soluble electrode plates. The bipolar electrodes of the Ⅱ1 unit insoluble electrode plates are graphite or titanium electrodes, and the bipolar electrodes of the Ⅱ2 unit soluble electrode plates can be aluminum powder mixed electrodes.

[0085] Specifically, in step S4, it includes:

[0086] If the pH value after the plate flow channel of the primary electrode reactor is less than the first preset pH value, it is determined that the electrochemical reaction inside the primary electrode reactor meets the preset standard;

[0087] If the pH value after the plate flow channel of the primary electrode reactor is greater than or equal to the first preset pH value, it is determined that the electrochemical reaction inside the primary electrode reactor does not meet the preset standard.

[0088] It is understandable that the actual implementers can set the first preset pH value according to the actual situation or based on the average pH value after the plate flow channel of the primary electrode reactor after electrochemical treatment that has passed the qualification test in historical data. Preferably, the first preset pH value is set in the range of 10 to 12.

[0089] Specifically, in the step S4, it also includes:

[0090] If the electrochemical reaction inside the primary electrode reactor does not meet the preset standard, a preset regulator is introduced into the primary electrode reactor.

[0091] Specifically, the amount of the preset adjusting substance introduced is determined according to the difference between the pH value after the electrode plate flow channel of the primary electrode reactor and the first preset pH value.

[0092] It is understandable that if the electrochemical reaction inside the primary electrode reactor does not meet the preset standard, it indicates that the highly active calcium ions, aluminum ions and OH ions produced by direct ionization of electrolysis and soluble electrodes are insufficient. Therefore, a preset adjuster can be introduced into the primary electrode reactor for supplementation. The preset adjuster can be aluminum metal powder or a mixture of aluminum metal powder and calcium oxide powder.

[0093] In implementation, the seventh intermediate value is determined according to the difference between the pH value after the plate flow channel of the primary electrode reactor and the first preset pH value, the eighth intermediate value is determined according to the ratio of the seventh intermediate value to the first preset pH value, and the amount of the preset adjustment substance introduced is determined according to the product of the eighth intermediate value and the standard introduction amount. The actual implementer can set the standard introduction amount according to the actual situation or based on the average of the introduction amounts of the preset adjustment substances of the electrochemical processes that have passed the qualification test and in which the preset adjustment substances are introduced into the primary electrode reactor in historical data.

[0094] Step S5, determining the secondary current concentration and the secondary voltage of the electrochemical treatment process in the secondary electrode reactor according to the pH before and after the electrode plate flow channel of the primary electrode reactor;

[0095] See also Figure 3 As shown, it is a schematic diagram of a process for determining the secondary current concentration and the secondary voltage according to an embodiment of the present invention; specifically, in the step S5, it includes:

[0096] Step S51, determining a second correlation coefficient according to the pH before and after the plate flow channel of the primary electrode reactor;

[0097] Step S52, determining the secondary current concentration according to the second correlation coefficient and the standard current concentration, and determining the secondary voltage according to the second correlation coefficient and the standard voltage.

[0098] In implementation, the second correlation coefficient is determined based on the ratio of the pH value before the electrode plate flow channel of the primary electrode reactor to the pH value after the electrode plate flow channel of the primary electrode reactor, the current concentration of the electrochemical treatment process in the secondary electrode reactor, i.e., the secondary current concentration, is determined based on the product of the second correlation coefficient and the standard current concentration, and the voltage of the electrochemical treatment process in the secondary electrode reactor, i.e., the secondary voltage, is determined based on the product of the second correlation coefficient and the standard voltage.

[0099] The present invention determines the second correlation coefficient by the pH before and after the plate flow channel of the primary electrode reactor, and the secondary current concentration and the secondary voltage determined thereby can improve the reaction speed of the electrochemical process in the primary electrode reactor.

[0100] Step S6, detecting the pH value before and after the electrode plate flow channel of the secondary electrode reactor after the second reaction time to determine whether the electrochemical reaction inside the secondary electrode reactor meets the preset standard. If not, determining the current concentration adjustment amount and the voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor according to the pH value before and after the electrode plate flow channel of the secondary electrode reactor.

[0101] In implementation, the second reaction time starts from the time point when the circulating water inside the primary electrode reactor begins to flow into the secondary electrode reactor. Preferably, the second reaction time is set in the range of 2 min to 5 min.

[0102] Specifically, step S6 includes:

[0103] If the pH value after the plate flow channel of the secondary electrode reactor is less than a second preset pH value, it is determined that the electrochemical reaction inside the secondary electrode reactor meets the preset standard;

[0104] If the pH value after the plate flow channel of the secondary electrode reactor is greater than or equal to the second preset pH value, it is determined that the electrochemical reaction inside the secondary electrode reactor does not meet the preset standard.

[0105] It is understandable that the actual implementers can set the second preset pH value according to the actual situation or based on the average pH value after the secondary electrode reactor plate flow channel after electrochemical treatment that has passed the qualification test in historical data. Preferably, the second preset pH value is set in the range of 7.5 to 9.

[0106] In implementation, if it is determined that the electrochemical reaction inside the secondary electrode reactor does not meet the preset standard, the circulating water in the secondary electrode reactor can be returned to the primary electrode reactor.

[0107] Specifically, step S6 includes:

[0108] Determining the current concentration adjustment amount of the electrochemical treatment process in the secondary electrode reactor according to the difference in pH before and after the electrode plate flow channel of the secondary electrode reactor and the standard current concentration;

[0109] The voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor is determined according to the difference in pH before and after the electrode plate flow channel of the secondary electrode reactor and the standard voltage.

[0110] In implementation, the ninth intermediate value is determined based on the ratio of the pH difference before and after the electrode plate flow channel of the secondary electrode reactor to the second preset pH value, the current concentration adjustment amount of the electrochemical treatment process in the secondary electrode reactor is determined based on the product of the ninth intermediate value and the standard current concentration, and the voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor is determined based on the product of the ninth intermediate value and the standard voltage.

[0111] The present invention performs electrochemical treatment on circulating water by setting a two-stage reactor, directly ionizing highly active calcium ions and aluminum ions and OH ions generated by electrolysis and dissolution electrodes, and accurately generating the amount of calcium, aluminum ions and hydroxide ions by accurately controlling the electrochemical current and voltage, and increasing the concentration of reactants by electric field voltage enrichment, accelerating the reaction speed, and improving the removal rate of chlorine and hardness removal of circulating water. The primary current concentration and primary voltage of the electrochemical treatment process in the primary electrode reactor are determined according to the chloride ion concentration and the conductivity of the circulating water, and the current concentration adjustment method and voltage adjustment method of the electrochemical treatment process in the primary electrode reactor are determined according to the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor. The circulating water is treated with the primary current concentration and primary voltage determined in this way, and the reaction speed can be increased. The secondary current concentration and secondary voltage of the electrochemical treatment process in the secondary electrode reactor are determined according to the pH before and after the electrode plate flow channel of the primary electrode reactor, and the reaction speed can be further increased. The removal rate can be improved by judging the pH value before and after the plate flow channel of the primary electrode reactor after the preset reaction time and the pH value before and after the plate flow channel of the secondary electrode reactor after the preset reaction time. Subsequent operations are performed only after the preset standards are met.

[0112] It is understandable that during the electrochemical treatment process, controlling the temperature of the circulating water at 20°C to 40°C can increase the reaction speed and removal rate. The soluble electrodes of the primary electrode reactor and the secondary electrode reactor can be composed of a titanium electrode skeleton and a metal palladium and platinum mesh frame as a conductive grid. Aluminum metal powder and calcium oxide powder are mixed and evenly filled in the frame and compacted to form a soluble electrode, wherein the amount of calcium oxide is set according to the calcium content of the circulating water. A high-frequency pulse reversal power supply is added to the electrodes of the primary electrode reactor and the secondary electrode reactor. The high-frequency power supply can continuously change the polarity of the electric field to prevent the electrode plates from scaling or passivation and affect the reaction effect. The dissociated aluminum ions and hydroxide ions generate aluminates and calcium ions generate aluminum calcium salts, enriching calcium ions and chloride ions in the water to form a high concentration reaction area and generate calcium aluminum salts.

[0113] In a specific embodiment, see Figure 6As shown, the lower part of the electrode area of ​​the primary electrode reactor and the secondary electrode reactor is a precipitation area, and a reflux clarification area is set in the precipitation area to improve the clarification and precipitation effect of dechlorination and water, and the precipitate is discharged from the reactor from the bottom. The reaction area of ​​the primary electrode reactor and the secondary electrode reactor is provided with an inserted ultrasonic regular cleaning head to clean the precipitate attached to the electrode plate in the reactor. The length of the reaction area of ​​the primary electrode reactor is 2m to 5m, the length of the reaction area of ​​the secondary electrode reactor is 4m to 6m, the height of the electrode area of ​​the primary electrode reactor and the secondary electrode reactor is 0.8m to 1.5m, the height of the bottom precipitation area is 3m to 5m, and the bypass filtration volume is 5% to 6% of the circulating water volume. The present invention can effectively control the amount of aluminum ions and hydroxide ions while forming calcium aluminum chlorine Freund's salt without excessively producing aluminates and calcium oxides, causing chloride salts to re-enter the water and reduce the dechlorination effect.

[0114] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An electrochemical treatment method for removing chlorine and hardness from circulating water, characterized in that: include: Step S1, pre-treating the circulating water, and detecting the chloride ion concentration and conductivity of the pre-treated circulating water; Step S2, passing the pretreated circulating water into a primary electrode reactor, and determining a primary current concentration and a primary voltage of an electrochemical treatment process in the primary electrode reactor according to the chloride ion concentration and the conductivity; Step S3, determining a current concentration adjustment method and a voltage adjustment method for the electrochemical treatment process in the primary electrode reactor according to a water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor; Step S4, detecting the pH before and after the electrode plate flow channel of the primary electrode reactor after the first reaction time to determine whether the electrochemical reaction inside the primary electrode reactor meets the preset standard, and if so, passing the circulating water inside the primary electrode reactor into the secondary electrode reactor; Step S5, determining the secondary current concentration and the secondary voltage of the electrochemical treatment process in the secondary electrode reactor according to the pH before and after the electrode plate flow channel of the primary electrode reactor; Step S6, detecting the pH value before and after the electrode plate flow channel of the secondary electrode reactor after the second reaction time to determine whether the electrochemical reaction inside the secondary electrode reactor meets the preset standard. If not, determining the current concentration adjustment amount and the voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor according to the pH value before and after the electrode plate flow channel of the secondary electrode reactor.

2. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 1, characterized in that: In the step S2, it includes: Step S21, determining a first correlation coefficient according to the chloride ion concentration and the conductivity; Step S22, determining the primary current concentration according to the first correlation coefficient and the standard current concentration, and determining the primary voltage according to the first correlation coefficient and the standard voltage.

3. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 2, characterized in that: In the step S3, it includes: If the water flow rate difference between the first electrode plate and the second electrode plate in the primary electrode reactor is greater than the first preset flow rate difference, reducing the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor; If the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor is less than or equal to the second preset flow rate difference, the current concentration and voltage of the electrochemical treatment process in the primary electrode reactor are increased.

4. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 3, characterized in that: In the step S3, it includes: Determining a reduction range of current concentration / voltage according to a water flow rate difference between a first electrode plate and a second electrode plate in the primary electrode reactor and a first preset flow rate difference; The increase range of the current concentration / voltage is determined according to the water flow rate difference between the first electrode plate and the second electrode plate inside the primary electrode reactor and the second preset flow rate difference.

5. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 4, characterized in that: In the step S4, it includes: If the pH value after the plate flow channel of the primary electrode reactor is less than the first preset pH value, it is determined that the electrochemical reaction inside the primary electrode reactor meets the preset standard; If the pH value after the plate flow channel of the primary electrode reactor is greater than or equal to the first preset pH value, it is determined that the electrochemical reaction inside the primary electrode reactor does not meet the preset standard.

6. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 5, characterized in that: In the step S5, it includes: Step S51, determining a second correlation coefficient according to the pH before and after the electrode plate flow channel of the primary electrode reactor; Step S52, determining the secondary current concentration according to the second correlation coefficient and the standard current concentration, and determining the secondary voltage according to the second correlation coefficient and the standard voltage.

7. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 6, characterized in that: In the step S6, it includes: If the pH value after the plate flow channel of the secondary electrode reactor is less than a second preset pH value, it is determined that the electrochemical reaction inside the secondary electrode reactor meets the preset standard; If the pH value after the plate flow channel of the secondary electrode reactor is greater than or equal to the second preset pH value, it is determined that the electrochemical reaction inside the secondary electrode reactor does not meet the preset standard.

8. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 7, characterized in that: In the step S6, it includes: Determining the current concentration adjustment amount of the electrochemical treatment process in the secondary electrode reactor according to the difference in pH before and after the electrode plate flow channel of the secondary electrode reactor and the standard current concentration; The voltage adjustment amount of the electrochemical treatment process in the secondary electrode reactor is determined according to the difference in pH before and after the electrode plate flow channel of the secondary electrode reactor and the standard voltage.

9. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 5, characterized in that: In the step S4, it also includes: If the electrochemical reaction inside the primary electrode reactor does not meet the preset standard, a preset regulator is introduced into the primary electrode reactor.

10. The electrochemical treatment method for removing chlorine and hardness from circulating water according to claim 9, characterized in that: In the step S4, it includes: The amount of the preset adjusting substance introduced is determined according to the difference between the pH value after the plate flow channel of the primary electrode reactor and the first preset pH value.

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