A chemical water treatment system

Abstract

The present application relates to the technical field of chemical water treatment, and discloses a chemical water treatment system. The system comprises a pretreatment unit, an ion exchange resin unit and a regenerated water recovery unit. The pretreatment unit comprises a multi-medium filter, an activated carbon filter and a reverse osmosis device connected in sequence. The ion exchange resin unit comprises a cation resin bed, an anion resin bed and an ion exchange mixed bed connected in sequence. The water inlet of the cation resin bed is connected with the water outlet of the pretreatment unit. The regenerated water recovery unit is used for recovering or recycling the cleaning water of the ion exchange resin unit, and comprises a regenerated water control system, a circulating water tank and a neutralization tank. The regenerated water control system comprises a detection unit, a signal processing unit and a control unit. The chemical water treatment system has low water production ratio, high desalted water volume and low wastewater discharge. On the basis of effectively cleaning the ion exchange resin, the water meeting the standard is recovered and utilized, so that the water resource is recovered and utilized.

Description

Technical Field

[0001] This invention relates to the technical field of chemical water treatment, and particularly to a chemical water treatment system. Background Technology

[0002] As one of the public works facilities in a refining and chemical enterprise, the chemical water treatment system produces qualified demineralized water, which is mainly supplied to the boiler system and oil refining production units. The system is designed to use fresh water and reclaimed water as the source of industrial water. After multiple filtrations, it undergoes desalination and decarbonization treatment, and then is treated by ion exchange resin to remove anions and cations. The resulting demineralized water is sent to the plant's demineralized water pipeline network for use by the production units.

[0003] Ion exchange resins will reach saturation and become ineffective after prolonged use. At this point, the ion exchange resin needs to be cleaned. In existing technologies, all wastewater from cleaning the ion exchange resin is treated in a neutralization wastewater tank before being discharged, resulting in high system water consumption and a high ratio of chemically treated water, thus wasting water resources. Summary of the Invention

[0004] This invention addresses the technical problem that existing chemical water treatment systems consume large amounts of water and waste water resources when cleaning failed ion exchange resins. It provides a chemical water treatment system that, while effectively cleaning the ion exchange resins, also recycles a portion of the water that meets the required standards, thus achieving water conservation.

[0005] The purpose of this invention is to provide a chemical water treatment system, including a pretreatment unit, an ion exchange resin unit, and a reclaimed water recovery unit;

[0006] The pretreatment unit includes a multi-media filter, an activated carbon filter, and a reverse osmosis device connected in sequence; the multi-media filter and the activated carbon filter are used to remove solid impurities from the water; the reverse osmosis device is used to remove charged ions and inorganic substances.

[0007] The ion exchange resin unit includes a cation exchange resin bed, an anion exchange resin bed, and an ion exchange mixed bed connected in sequence; the cation exchange resin bed, anion exchange resin bed, and ion exchange mixed bed are respectively provided with a filtered water outlet and a cleaning water outlet; the inlet of the cation exchange resin bed is connected to the outlet of the pretreatment unit; the ion exchange resin unit is used to filter out anions and cations from the water;

[0008] The reclaimed water recovery unit includes a reclaimed water control system, a recovery tank, a circulating water tank, and a neutralization tank.

[0009] The inlet of the recovery tank is connected to the cleaning water outlet of the cation exchange resin bed, the cleaning water outlet of the anion exchange resin bed, and the cleaning water outlet of the ion exchange mixed bed.

[0010] The neutralization tank, the circulating water tank, and the pretreatment unit are respectively connected to the outlet of the recovery tank via a first pipeline, a second pipeline, and a third pipeline; the first pipeline is equipped with a first valve, the second pipeline is equipped with a second valve, and the third pipeline is equipped with a third valve;

[0011] The reclaimed water control system includes a detection unit and a DCS controller communicatively connected to the detection unit; the detection unit is used to detect the water quality at the outlet of the recycling tank; the DCS controller is communicatively connected to the first valve, the second valve, and the third valve, and is used to control the opening and closing of the first valve, the second valve, and the third valve based on data from the detection unit.

[0012] According to a preferred embodiment of the present invention, when the signal processing unit determines that the real-time parameter is greater than the first set value, the control unit opens the first valve, and the cleaning water is sent to the neutralization tank through the first pipeline;

[0013] When the real-time parameter is greater than the second set value and less than the first set value, the control unit opens the second valve and closes the first valve, and the cleaning water is sent to the circulating water tank through the second pipeline;

[0014] When the real-time parameter is less than the second set value, the control unit opens the third valve and closes the second valve, and the cleaning water is sent back to the pretreatment unit through the third pipeline. The first set value is greater than the second set value.

[0015] In actual use, under normal conditions, the chemical water treatment system is used to treat industrial water (fresh industrial water source and / or recycled water). The industrial water enters the pretreatment unit and then the ion exchange resin unit in sequence. Solid impurities are removed in the pretreatment unit, and anions and cations are removed in the ion exchange resin unit. The desalinated water that meets the production requirements is then transported to the production unit through pipelines.

[0016] Ion exchange resin units will reach saturation after prolonged use, thus failing and becoming unable to filter ions. Therefore, the ion exchange resin units need to be cleaned.

[0017] During the cleaning of the ion exchange resin unit, demineralized water (industrial water with solid impurities and anions / cations removed) is used for convective rinsing. Experiments showed that the water quality remained relatively stable during the last one-third to one-half of the cleaning process, and the quality of the rinsing wastewater was essentially the same as that of fresh industrial water, meeting the requirements for reuse in the raw water tank or for replenishing circulating water. Therefore, this invention selects to recycle the cleaning water that meets the parameter standards (empirically, this is the last half to one-third of the cleaning process), and the recycling is achieved through a DCS controller.

[0018] The DCS (Distributed Control System) has input, output, and setting functions. It filters numerical signals from instruments based on conditions and selects the corresponding valves to operate. The detection unit monitors real-time parameters of the cleaning water; the signal processing unit compares setpoints with real-time parameters; and the control unit controls the first, second, or third valve to send the cleaning water to the neutralization tank, circulating water tank, or back to the pretreatment unit. Only one of the first, second, or third valves is open, while the other two are closed. The filtered solution containing impurities is transported to the neutralization tank, and after manual adjustment, it meets discharge standards.

[0019] According to a preferred embodiment of the present invention, the detection unit includes a conductivity meter, a pH meter, a silicon content meter, and / or a sodium content meter.

[0020] According to a preferred embodiment of the present invention, the ion exchange resin unit further includes a demineralized water tank, which is connected to the filtered water outlet of the ion exchange mixed bed.

[0021] According to a preferred embodiment of the present invention, the ion exchange resin unit further includes a second water pump disposed at the outlet of the demineralized water tank, the second water pump being used to deliver the demineralized water to the production equipment.

[0022] According to a preferred embodiment of the present invention, the recovery tank is connected via a fourth pipeline to the cleaning water outlet of the cation exchange resin bed, the cleaning water outlet of the anion exchange resin bed, and the cleaning water outlet of the ion exchange mixed bed.

[0023] According to a preferred embodiment of the present invention, the fourth pipeline is provided with valves at the cleaning water outlets of the cation exchange resin bed, the anion exchange resin bed, and the ion exchange mixed bed, respectively.

[0024] According to a preferred embodiment of the present invention, the chemical water treatment system further includes an intermediate water tank and a first water pump sequentially disposed between the reverse osmosis unit and the cation exchange resin bed.

[0025] According to a preferred embodiment of the present invention, the pretreatment unit further includes a raw water buffer tank; the raw water buffer tank is provided with a fresh water inlet, a grey water inlet, a cleaning water inlet and a buffer water outlet; the buffer water outlet of the raw water buffer tank is connected to the inlet of the multi-media filter, and the recovery tank is connected to the cleaning water inlet of the raw water buffer tank via the third pipeline.

[0026] According to a preferred embodiment of the present invention, the reclaimed water control system further includes a reclaimed water booster pump disposed at the outlet of the recycling tank, for pumping the reclaimed water in the recycling tank to the neutralization tank, the circulating water tank, or the pretreatment unit.

[0027] According to a preferred embodiment of the present invention, the neutralization tank is provided with an external discharge pipeline.

[0028] The volume of the recycling tank should not exceed the hourly flow rate of the cleaning water.

[0029] The recycling tank is not large in volume and is only used for mixing the cleaning water. There is not much cleaning water residue, so it will not affect the accuracy of real-time parameters.

[0030] The water production ratio refers to the amount of qualified demineralized water produced by a chemical water treatment system after treating a certain amount of raw water (fresh industrial water and / or recycled water). The ratio between the raw water volume and the qualified demineralized water volume is the water production ratio. The higher the water production ratio, the higher the water consumption of the chemical water treatment system.

[0031] The beneficial effects of this invention are as follows: The chemical water treatment system of this invention has a low chemical water production ratio, high demineralized water output, and low wastewater discharge. Based on the effective cleaning of ion exchange resins, this invention also recycles a portion of the water resources that meet the standards, thus achieving water resource recycling. Attached Figure Description

[0032] Figure 1 This is a process flow diagram of the chemical water treatment system of the present invention.

[0033] Among them, 1-raw water buffer tank, 2-multi-media filter, 3-activated carbon filter, 4-reverse osmosis device, 5-cation resin bed, 6-anion resin bed, 7-ion exchange mixed bed, 8-neutralization tank, 91-DCS controller, 92-detection unit, 93-first valve, 94-second valve, 95-third valve, 10-recovery tank, 11-circulating water tank. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0035] The water production ratio refers to the ratio between the amount of raw water and the amount of qualified demineralized water that a chemical water treatment system can produce after treating a certain amount of raw water. A higher water production ratio results in higher water consumption for the chemical water treatment system.

[0036] like Figure 1 In the illustrated embodiment, the chemical water treatment system includes a pretreatment unit, an ion exchange resin unit, and a reclaimed water recovery unit;

[0037] The pretreatment unit includes a raw water buffer tank 1, a multi-media filter 2, an activated carbon filter 3, and a reverse osmosis unit 4 connected in sequence.

[0038] The ion exchange resin unit includes a cation exchange resin bed 5, an anion exchange resin bed 6 and an ion exchange mixed bed 7 connected in sequence; the demineralized water outlet of the ion exchange mixed bed 7 is also equipped with a demineralized water tank and a second water pump;

[0039] The reclaimed water recycling unit includes a reclaimed water control system, a circulating water tank 11, a recycling tank 10, and a neutralization tank 8. The reclaimed water control system includes a detection unit 92 and a DCS controller 91. The detection unit 92 is used to test the real-time parameters of the neutralization tank 8. The DCS controller 91 includes a signal processing unit and a control unit. The signal processing unit is used to compare the real-time parameters at the outlet of the neutralization tank 8 with the magnitudes of a first set value and a second set value. The control unit is communicatively connected to a first valve 93, a second valve 94, and a third valve 95, and controls the opening and closing of the first valve 93, the second valve 94, and the third valve 95 according to the magnitude relationships.

[0040] An intermediate water tank and a first water pump are connected between the pretreatment unit and the ion exchange resin unit.

[0041] The chemical water treatment system is used to treat fresh industrial water and / or recycled water (hereinafter referred to as raw water). The raw water passes through the raw water buffer tank 1, multi-media filter 2, activated carbon filter 3, reverse osmosis unit 4, intermediate water tank, first water pump, cation exchange resin bed 5, anion exchange resin bed 6, ion exchange mixed bed 7, demineralized water tank and second water pump in sequence to obtain demineralized water that meets the production requirements, which is then transported to the production unit through pipelines.

[0042] After prolonged use, the ion exchange resin unit will reach saturation and become ineffective, failing to filter ions. Therefore, the ion exchange resin unit needs to be cleaned.

[0043] When cleaning the ion exchange resin unit, the reclaimed water recovery unit of the chemical water treatment system starts to operate; the reclaimed water recovery unit includes a reclaimed water control system, a circulating water tank 11, a recovery tank 10, and a neutralization tank 8; the recovery tank 10, the neutralization tank 8, the circulating water tank 11, and the raw water buffer tank 1 are connected by a first pipeline, a second pipeline, and a third pipeline, respectively; a first valve 93, a second valve 94, and a third valve 95 are respectively installed on the first pipeline, the second pipeline, and the third pipeline; by controlling the opening and closing of the valves, the flow direction of the cleaning water is controlled.

[0044] The bottoms of the cation exchange resin bed 5, anion exchange resin bed 6, and ion exchange mixed bed 7 are all equipped with cleaning pipes connecting to the neutralization tank 8. The recovery tank 10 is connected to the cleaning water outlets of the cation exchange resin bed 5, anion exchange resin bed 6, and ion exchange mixed bed 7 via a fourth pipe. The fourth pipe includes cleaning branch I, cleaning branch II, and cleaning branch III. Taking the cation exchange resin bed 5 as an example, the bottom of the cation exchange resin bed 5 is equipped with cleaning pipe I, from which cleaning branch I is led. Cleaning pipe I is used to pass the initial wastewater into the recovery tank 10. Cleaning branch I is used to pass the later qualified cleaning water into the recovery tank 10. The initial stage refers to the first half to two-thirds of the stage, and the later stage refers to the last one-third to one-half of the stage (cleaning water meeting the parameter standards is recovered, and the recovery method is achieved through a reclaimed water control system). Similarly, the anion exchange resin bed 6 is equipped with cleaning pipe II and cleaning branch II; the ion exchange mixed bed 7 is equipped with cleaning pipe III and cleaning branch III. Valves are installed on cleaning pipeline I, cleaning branch I, cleaning pipeline II, cleaning branch II, cleaning pipeline III, and cleaning branch III.

[0045] The reclaimed water control system includes a detection unit 92 and a DCS controller 91; the detection unit 92 and the DCS controller 91 are communicatively connected; the detection unit 92 is used to test the real-time parameters of the recycling tank 10; the DCS controller 91 includes a signal processing unit and a control unit; wherein, the signal processing unit is used to compare the real-time parameters of the recycling tank 10 with the magnitude relationship of a first set value and a second set value; the control unit is communicatively connected with a first valve 93, a second valve 94 and a third valve 95, and controls the opening and closing of the first valve 93, the second valve 94 and the third valve 95 according to the magnitude relationship.

[0046] When the signal processing unit determines that the real-time parameter is greater than the first set value, the control unit opens the first valve 93, and the cleaning water is sent to the neutralization tank 8 through the first pipeline.

[0047] When the real-time parameter is greater than the second set value and less than the first set value, the control unit opens the second valve 94 and closes the first valve, and the cleaning water is sent to the circulating water tank 11 through the second pipeline;

[0048] When the real-time parameter is less than the second set value, the control unit opens the third valve 95 and closes the second valve 94, and the cleaning water is sent back to the raw water buffer tank 1 of the pretreatment unit through the third pipeline.

[0049] For example, the detection unit is used to test the real-time parameters of the cleaning water at the inlet of the first valve 93, the second valve 94, and the third valve 95; or, the detection unit is used to test the real-time parameters of the cleaning water in the recovery tank 10. The real-time parameters include conductivity, pH value, silica content, and sodium content. The signal processing unit compares the real-time parameters with a first set value and a second set value. Based on the comparison result with the first set value, the first valve 93 is controlled to open or close; based on the comparison result with the first and second set values, the second valve 94 is controlled to open or close; based on the comparison result with the second set value, the third valve 95 is controlled to open or close. Only one of the first valve 93, the second valve 94, and the third valve 95 is open, while the other two are closed.

[0050] For example, the first set value is set to 6.8 ≤ pH ≤ 9.5 and S > 12000 and SiO2 > 200 mg / L and Na + >1800 mg / L;

[0051] The second set value is 6 ≤ pH ≤ 9 and S > 1200 and SiO2 > 20 mg / L and Na + >100 mg / L; S is electrical conductivity; SiO2 is silicon dioxide content; Na + This refers to the sodium ion content;

[0052] When the first set value is met, the control unit controls the first valve 93 to open; the cleaning water flows back to the neutralization tank 8 through the first pipeline;

[0053] When the first set value is not met, the second set value is met. When the second set value is met, the first valve 93 is closed and the second valve 94 is opened; the cleaning water flows back to the circulating water tank 11 through the second pipeline.

[0054] When the second set value is not met, the third valve 95 opens; the cleaning water flows back to the original water buffer tank 1 through the third pipeline;

[0055] The wastewater from the first half to two-thirds of the process is introduced into the neutralization tank 8 through the cleaning pipeline. The conductivity, pH value, silicon content and sodium content of the early cleaning wastewater are relatively high. It can be introduced into the neutralization tank 8 manually through the cleaning pipeline or through the cleaning branch. The DCS controller 91 tests it in real time and controls the first valve 93 to open based on the test results. The cleaning water flows back to the neutralization tank 8 through the first pipeline.

[0056]

Example

[0057] The existing design of the entire 200m 3 The / h chemical water treatment system adopts the reverse osmosis + ion exchanger process technology route. The water consumption of the chemical water treatment process is relatively high, and the key control index, the chemical water production ratio, is designed to be 1.10t / t.

[0058] The ion exchanger in this application's chemical water treatment system has reached its production operation cycle and has failed due to excessive ion content in the effluent (Na+ in the cation exchanger bed effluent). + For effluents with SiO2 >200 μg / L (anion exchange resin bed effluent SiO2 >100 μg / L; ion exchange mixed bed effluent SiO2 >20 μg / L), regeneration is required to restore resin activity. After the acid and alkali exchange reactions in the regeneration of cation exchange resin bed 5, anion exchange resin bed 6, and ion exchange mixed bed 7, a large amount of demineralized water (product demineralized water conductivity <10 μS / cm) is required to perform a 90-minute convective rinse on the ion exchange resin unit. This process is divided into two stages.

[0059] The first half of the process involves convective rinsing, which is highly unstable. In the first 40 minutes, the conductivity, pH, silica content, and / or sodium content of the rinsing water are relatively high. All of the rinsing water is discharged into neutralization tank 8. Furthermore, through on-site tracking and analysis of the rinsing water quality during the regeneration process of the ion exchange resin unit, the rinsing water tends to stabilize after 45 minutes of convective rinsing.

[0060] The latter half of the flushing process involves convection rinsing, resulting in relatively stable water quality (flushing drainage conductivity: 1027 μS / cm). The quality of the cleaning water is essentially the same as that of fresh industrial water. This portion of water is then discharged into the recycling tank 10. The detection unit 92 of the reclaimed water control system tests the cleaning water in the recycling tank 10. The DCS controller 91 controls the first valve 93, the second valve 94, and the third valve 95, sending the cleaning water from the recycling tank 10 to the neutralization tank 8, the circulating water tank 11, or the raw water buffer tank 1, as needed.

[0061] In long-term comprehensive utilization, this invention recycles the cleaning water from each ion exchange resin unit and discharges 16m³ of wastewater from the subsequent 40-minute convective rinsing. 3 ±1m 3 Recycling.

[0062] By upgrading the technology and adding an ion exchanger flushing wastewater recycling system, as well as a DCS controller 91 for screening and distribution, 16m³ of the compliant regeneration flushing wastewater will be processed within the last 40 minutes. 3 ±1m 3 The ion exchanger was put into operation for 8 minutes, and the backwash drainage was 14m³. 3 The water is uniformly recycled into the raw water buffer tank 1 or the circulating water pool 11 to improve the comprehensive utilization rate of water resources and achieve the goals of water conservation, emission reduction, increased production and efficiency.

[0063] This invention optimizes and modifies the original chemical water treatment process, reducing the water production ratio from the original design value of 1.10 t / t to 1.089 t / t, a comprehensive reduction of 1.0%, resulting in a comprehensive water saving of 16,200 tons and a reduction of 1,800 tons of fresh water replenishment for circulating water. After the technological upgrade and commissioning, this 200m³ system...3 The / h chemical water treatment system can produce an additional 16,200 tons of demineralized water and reduce wastewater discharge by approximately 19,600 tons annually; this can generate 268,500 yuan in water savings and emission reductions for the company annually (the unit price of demineralized water purchased from the company by external units is 14.0 yuan / m³). 3 Company sewage discharge fee: 2.10 yuan / m³ 3 Fresh water: 2.18 yuan / m³ 3 ).

[0064] A new reuse process has been added to the flushing drainage pipelines of cation exchangers 5, anion exchangers 6, and mixed ion exchangers 7 in the chemical water treatment system. This process recycles the 16m³ of wastewater after 40 minutes of regeneration and convection flushing of the ion exchangers. 3 ±1m 3 The collected water is sent to the recovery tank 10. The cleaning water in the recovery tank 10 is then sent to the raw water buffer tank 1 by a newly added booster pump. The water is then mixed with fresh water and used for production or without being added to the circulating water. (Analysis of process path principles and valve action control) Through process technology optimization and transformation, the demineralized water production of the chemical water treatment system can be increased, and the chemical water production ratio, water consumption index and fresh water replenishment of the circulating water can be reduced. This will greatly enhance the competitiveness of this chemical water treatment process technology and create certain economic benefits for the enterprise.

[0065] The present invention has been described with reference to typical embodiments, but it should be understood that the terms used herein are descriptive and explanatory, not limiting. Modifications and revisions can be made to the invention within the scope of the claims as specified herein, without departing from the scope and spirit of the invention. Although the invention described herein relates to specific methods, materials, and embodiments, it does not imply that the invention is limited to the specific examples disclosed herein; rather, the invention can be extended to all other methods and applications having the same function.

Claims

1. A chemical water treatment system, characterized in that, It includes a pretreatment unit, an ion exchange resin unit, and a reclaimed water recovery unit; The pretreatment unit includes a multi-media filter, an activated carbon filter, and a reverse osmosis device connected in sequence. The ion exchange resin unit includes a cation exchange resin bed, an anion exchange resin bed, and an ion exchange mixed bed connected in sequence; the cation exchange resin bed, anion exchange resin bed, and ion exchange mixed bed are respectively provided with a filtered water outlet and a cleaning water outlet; the inlet of the cation exchange resin bed is connected to the outlet of the pretreatment unit. The reclaimed water recovery unit includes a reclaimed water control system, a recovery tank, a circulating water tank, and a neutralization tank. The inlet of the recovery tank is connected to the cleaning water outlet of the cation exchange resin bed, the cleaning water outlet of the anion exchange resin bed, and the cleaning water outlet of the ion exchange mixed bed. The neutralization tank, the circulating water tank, and the pretreatment unit are respectively connected to the outlet of the recovery tank via a first pipeline, a second pipeline, and a third pipeline; the first pipeline is equipped with a first valve, the second pipeline is equipped with a second valve, and the third pipeline is equipped with a third valve; The reclaimed water control system includes a detection unit and a DCS controller communicatively connected to the detection unit; the detection unit is used to detect the water quality at the outlet of the recycling tank; the DCS controller is communicatively connected to the first valve, the second valve, and the third valve, and is used to control the opening and closing of the first valve, the second valve, and the third valve based on data from the detection unit.

2. The chemical water treatment system according to claim 1, characterized in that, The detection unit includes a conductivity meter, a pH meter, a silicon content meter, and / or a sodium content meter.

3. The chemical water treatment system according to claim 1 or 2, characterized in that, The ion exchange resin unit also includes a demineralized water tank, which is connected to the filtered water outlet of the ion exchange mixed bed.

4. The chemical water treatment system according to claim 3, characterized in that, The ion exchange resin unit also includes a second water pump located at the outlet of the demineralized water tank, the second water pump being used to deliver the demineralized water to the production equipment.

5. The chemical water treatment system according to claim 1 or 2, characterized in that, The recovery tank is connected via a fourth pipeline to the cleaning water outlets of the cation exchange resin bed, the anion exchange resin bed, and the ion exchange mixed bed.

6. The chemical water treatment system according to claim 5, characterized in that, The fourth pipeline is equipped with valves at the cleaning water outlets of the cation exchange resin bed, the anion exchange resin bed, and the ion exchange mixed bed, respectively.

7. The chemical water treatment system according to claim 1 or 2, characterized in that, The chemical water treatment system also includes an intermediate water tank and a first water pump, which are sequentially arranged between the reverse osmosis unit and the cation exchange resin bed.

8. The chemical water treatment system according to claim 1 or 2, characterized in that, The pretreatment unit also includes a raw water buffer tank; the raw water buffer tank is provided with a fresh water inlet, a grey water inlet, a cleaning water inlet and a buffer water outlet; the buffer water outlet of the raw water buffer tank is connected to the inlet of the multi-media filter, and the recycling tank is connected to the cleaning water inlet of the raw water buffer tank via the third pipeline.

9. The chemical water treatment system according to claim 1 or 2, characterized in that, The reclaimed water control system also includes a reclaimed water booster pump located at the outlet of the recycling tank, used to pump the reclaimed water in the recycling tank to the neutralization tank, the circulating water tank, or the pretreatment unit.

10. The chemical water treatment system according to claim 1 or 2, characterized in that, The neutralization tank is equipped with an external drainage pipeline.

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