A monitoring control system for small molecule organic matter content in raw water

Abstract

The application discloses a kind of for the monitoring control system of small molecule organic matter content in raw water, the monitoring control system includes detection pipeline, TOC online analyzer and PLC control box;TOC online analyzer and the oxidant dosing pump and reducing agent dosing pump of ultrapure water preparation system are connected with PLC control box;Detection pipeline is led out from the outlet pipeline of raw water tank, and melt spray filter, activated carbon filter, two-stage reverse osmosis membrane and ion exchange resin tower are sequentially arranged on detection pipeline;The outlet water of ion exchange resin tower enters TOC online analyzer and carries out the detection of TOC concentration, and TOC online analyzer will be obtained TOC concentration with 4-20mA current signal conduction to PLC control box, and PLC control box will be received current signal into the required dosing amount under corresponding TOC concentration, then 4-20mA current signal is fed back to oxidant dosing pump and reducing agent dosing pump, and the required amount of oxidizing agent and reducing agent is added to the advanced oxidation unit of ultrapure water preparation system by adjusting the opening of dosing pump.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of monitoring control system for the content of small molecule organic matter in raw water. BACKGROUND

[0002] Integrated circuit industry needs to consume a large amount of ultra-pure water with extremely high water quality in the production process. For example, the total organic carbon (TOC) of 12-inch integrated circuit production using ultra-pure water is required to be less than 1 μg / L or even 0.5 μg / L. This puts higher requirements on the water quality of the raw water for preparing ultra-pure water.

[0003] The process flow of the ultra-pure water preparation system is shown in Figure 1 The raw water is mainly taken from tap water and reclaimed water, which contains a variety of small molecular weight, charge neutral organic matter such as urea, trihalomethane, isopropyl alcohol, acetone, etc., and shows seasonal or periodic fluctuations. The above-mentioned small molecule organic matter (molecular weight less than 350 Da) accounts for a small proportion (10% to 30%) in the raw water, but it is easy to penetrate the main organic matter removal units in the ultra-pure water preparation system, such as reverse osmosis membrane, ion exchange resin, 185 nm ultraviolet lamp, etc., causing the TOC of the terminal ultra-pure water to exceed the standard, which cannot meet the production and use requirements.

[0004] Currently, the monitoring method of TOC in terminal ultra-pure water and organic matter in raw water mainly uses TOC online analyzer, such as GE M9 online TOC analyzer in the United States, METTLER 4000TOCe online sensor in Switzerland, etc. This single total TOC content as the evaluation index of the raw water quality of the ultra-pure water preparation system cannot effectively reflect the actual situation that the fluctuation of the small molecular organic matter content in it affects the terminal effluent water quality, which causes problems to the increasingly precise integrated circuit production. In the existing ultra-pure water preparation process of integrated circuit industry, the way to solve the high TOC content of terminal ultra-pure water is to add a fixed proportion of oxidizing agent to the front-end raw water tank and other units after the TOC value of the terminal ultra-pure water continues to rise, even exceeds the standard. The above-mentioned method has the problems of missing water quality prediction, lagging control measures, and failing to adjust the dosage of oxidizing agent and reducing agent in real time according to the key small molecular pollutants. SUMMARY

[0005] The purpose of the present application is to provide a monitoring control system for the content of small molecule organic matter in raw water, which can monitor the content of small molecule organic matter in raw water that affects the terminal effluent water quality of the ultra-pure water preparation system in real time, and adjust the dosage of oxidizing agent and reducing agent in time based on the content, realize the deep removal of small molecule organic matter in raw water, and thus enable the ultra-pure water preparation system to cope with the content fluctuation of small molecule organic matter in raw water, and guarantee the TOC stability of terminal water quality to meet the standard.

[0006] Technical Solution: The present invention describes a monitoring and control system for the content of small molecule organic matter in raw water. The monitoring and control system includes a detection pipeline, an online TOC analyzer, and a PLC control box. The online TOC analyzer, as well as the oxidant and reductant dosing pumps of the ultrapure water preparation system, are all connected to the PLC control box. The detection pipeline extends from the outlet pipeline of the raw water tank and sequentially includes a melt-blown filter, an activated carbon filter, a two-stage reverse osmosis membrane, and an ion exchange resin tower. The effluent from the ion exchange resin tower enters the online TOC analyzer for TOC concentration detection. The online TOC analyzer transmits the obtained TOC concentration as a 4-20mA current signal to the PLC control box. The PLC control box converts the received current signal into the required dosage for the corresponding TOC concentration and then feeds it back as a 4-20mA current signal to the oxidant and reductant dosing pumps. By adjusting the opening of the dosing pumps, the required amount of oxidant and reductant is added to the advanced oxidation unit of the ultrapure water preparation system.

[0007] Based on the predefined linear relationship between the TOC detection range of 0–200 μg / L and the current signal of 4–20 mA (e.g.) Figure 5 As shown in Figure a), the online TOC analyzer transmits the detected TOC concentration as a corresponding current signal to the PLC control box. This is based on a predefined linear relationship between the dosage of 0–50 mg / L and the current signal of 4 mA–20 mA (e.g., ...). Figure 5 As shown in b), the PLC control box obtains the corresponding TOC concentration value through the current signal, and then calculates the dosage of each agent at the corresponding TOC concentration value based on the relationship between TOC concentration and agent dosage. This dosage is then converted into a corresponding current signal and transmitted to the corresponding dosing pump. This is based on a predefined linear relationship between the 0%–100% dosing pump opening and the 4mA–20mA current signal (e.g., ...). Figure 5 As shown in c), each dosing pump converts the corresponding current signal into an opening value for dosing.

[0008] Among them, the filter element of the meltblown filter is made of polypropylene fiber, and the filtration accuracy is 1μm~5μm.

[0009] The activated carbon filter is filled with granular activated carbon with an adsorption iodine value of 1000mg / g to 1800mg / g, and its function is to filter suspended particulate matter, oils and oxidizing substances in water.

[0010] Both stages of the reverse osmosis membrane are made of fouling-resistant polyamide material, with a filtration accuracy of 0.05μm to 0.1μm and an inlet pressure of 0.5MPa to 0.7MPa. The water production rate of the first-stage reverse osmosis membrane is 75% to 80%, and the water production rate of the second-stage reverse osmosis membrane is 85% to 95%. The two-stage reverse osmosis membrane is used to intercept organic matter with high molecular weight.

[0011] The ion exchange resin tower uses a sulfonic acid-based gel-type cation exchange resin and a quaternary ammonium-based gel-type anion exchange resin. The mass ratio of the two resins is 3:2, and the flow rate is 50 BV / h to 85 BV / h. It can adsorb polar substances with positive and negative charges in water.

[0012] The tap water / reclaimed water in the raw water tank contains various organic compounds with different molecular weights and charges. In order to obtain the content of small molecule organic compounds that can affect the terminal water quality of the ultrapure water preparation system in real time and accurately, the influent to be tested needs to be pretreated. The pretreatment process simulates the actual process of the ultrapure water preparation system, and adopts the method of melt-blown filter + activated carbon filter + two-stage reverse osmosis membrane + ion exchange resin tower. The influent flow rate of the test pipeline is 10L / h to 30L / h, and the influent pressure is 0.3MPa to 0.6MPa.

[0013] The flow rate ratio between the inlet flow rate of the detection pipeline and the outlet flow rate of the raw water pipeline is 1:100 to 1000.

[0014] Among them, based on existing methods for removing small molecule organic matter, the relationship between TOC concentration and the dosage of oxidant and reductant was constructed:

[0015] In the reaction system of bromide salt and oxidant

[0016] C1 = ax 3 +bx 2 +cx+d (1)

[0017] C2 = eC1 (2)

[0018]

[0019] In the formula, x is the TOC value of the effluent after treatment by the detection pipeline detected by the TOC online analyzer; a to g are chemical reaction coefficients, with values ​​of: a: 1000–2000, b: 5–6, c: 20–80, d: 7.9–8.5, e: 0.4–0.5, f: 0.6, g: 5–10; C1 is the concentration of bromide added to the system; C2 is the concentration of oxidant added to the system; C3 is the concentration of reductant added to the system; and M2 and M3 are the relative molecular masses of the oxidant and reductant, respectively.

[0020] In the reaction system of bromide and oxidant, the bromide is NaBr or KBr, the oxidant is one or more of NaClO, O3 or H2O2, and the reducing agent is NaHSO3.

[0021] Among them, based on existing methods for removing small molecule organic matter, the relationship between TOC concentration and the dosage of oxidant and reductant was constructed:

[0022] In the UV-activated oxidant reaction system

[0023] C4 = hx3 + ix 2 +jx+k (4)

[0024]

[0025] In the formula, x is the TOC value of the effluent after treatment by the detection pipeline detected by the TOC online analyzer; h to m are chemical reaction coefficients, with values ​​of: h: 1 to 10, i: 4 to 8, j: 7.6 to 10, k: 12 to 50, l: 0.8, m: 0 to 10; C4 is the concentration of oxidant added to the system; C5 is the concentration of reductant added to the system; and M4 and M5 are the relative molecular masses of the oxidant and reductant, respectively.

[0026] In the ultraviolet-activated oxidant reaction system, the oxidant is one or more of H2O2, NaClO, Na2S2O8 or KHSO5; a medium-pressure / low-pressure ultraviolet lamp is used to activate the oxidant, and the light wavelength range is 185nm to 300nm; the reducing agent is NaHSO3.

[0027] Using a NaBr / NaClO reaction system with NaHSO3 as the reducing agent, the TOC value of the effluent after treatment by the detection pipeline was set to 0.06 mg / L, corresponding to a terminal TOC value of 0.95 μg / L (<1 μg / L) for the ultrapure water preparation system. Therefore, the detected TOC value (0.06 mg / L) was taken as the baseline TOC value (TOC0). At this time, the ORP value of the water (without added oxidant) was 220 mV.

[0028] For different detected TOC values, different concentrations of NaBr and a proportional amount of NaClO were added to reduce the TOC value to the TOC0 level; simultaneously, NaHSO3 was added to reduce the redox potential (ORP) of the reaction system to its initial value (ORP0) before the addition of the oxidant. Experimental data are as follows:

[0029]

[0030]

[0031] Therefore, the equation relating the amount of NaBr added to the detected TOC value is:

[0032] C NaBr =1000x 3 +5x 2 +20x+7.9

[0033] The equation relating the amount of NaClO added to the amount of NaBr is:

[0034] C NaClO =0.4C NaBr

[0035] Therefore, the equation relating the amount of NaHSO3 added to the amount of NaClO is:

[0036] C NaHSO3 =084C NaClO +5;

[0037] Thus, the values ​​of the chemical reaction coefficients a to g are obtained.

[0038] Based on the relationship between TOC concentration and the dosage of oxidant and reductant, the dosage of oxidant and reductant is output based on the detected TOC concentration. The dosage is then converted into the dosing pump range according to the corresponding dosing current value of 4mA to 20mA. Finally, the reagents are delivered to the advanced oxidation unit of the ultrapure water preparation system through the dosing pipeline to achieve precise removal of small molecule organic matter in the raw water and avoid the failure of TOC in the terminal effluent of the ultrapure water preparation system due to fluctuations in the content of small molecule organic matter in the raw water.

[0039] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: The monitoring and control system of the present invention uses adsorption + filtration + ion exchange screening on the detection pipeline to obtain the concentration of neutral small molecule organic matter in the raw water. Based on the relationship between the TOC concentration value and the dosage of oxidant and reducing agent constructed in the early stage, it realizes the precise control of the dosage of the agent, thereby greatly reducing the impact of the fluctuation of the concentration of neutral small molecule organic matter in the raw water on the TOC of the terminal water of the ultrapure water preparation system, and thus ensuring the stable compliance of the terminal water quality; (2) The monitoring and control system of the present invention leads out the detection pipeline separately from the raw water tank outlet pipeline of the ultrapure water preparation system, which can obtain the change of neutral small molecule organic matter concentration in the raw water in a timely manner, and adopts the precise dosing method calculated by fitting, effectively avoiding the passive lagging measures taken due to the failure of the terminal water of the ultrapure water preparation system to meet the standards caused by the fluctuation of the raw water quality; thereby effectively reducing the dosage while reducing the subsequent desalination load. Attached Figure Description

[0040] Figure 1 A process flow diagram of an existing ultrapure water preparation system;

[0041] Figure 2 This is a schematic diagram of the monitoring principle of the monitoring and control system of the present invention;

[0042] Figure 3 A graph showing the relationship between the variation of small molecule organic matter content in raw water and the fluctuation of TOC in the final effluent of an existing ultrapure water system;

[0043] Figure 4A graph showing the relationship between the change in the content of small molecule organic matter in the raw water and the fluctuation of TOC in the terminal effluent of an ultrapure water preparation system containing the monitoring and control system of this invention.

[0044] Figure 5 The graphs show the linear relationships between TOC detection range and current signal, dosage and current signal, and dosing pump opening and current signal, respectively. Detailed Implementation

[0045] Example 1

[0046] A semiconductor factory uses tap water as the raw water for its ultrapure water preparation system, and the TOC requirement for the final effluent is less than 1 μg / L. Due to agricultural fertilization during March and April, the content of urea-related small-molecule organic matter (as TOC) in the tap water increased from 30-50 μg / L to 80-120 μg / L.

[0047] This embodiment removes urea-like small molecule organic matter by adding NaBr and NaClO to the raw water tank. The specific implementation steps of the monitoring and control system of this invention are as follows:

[0048] Step 1: Draw 10L / h of test water from the raw water tank of the ultrapure water preparation system and deliver it to the melt-blown filter cartridge via the test booster pump;

[0049] Step 2: The test water is sequentially treated through a melt-blown filter, an activated carbon filter, a two-stage reverse osmosis membrane, and an ion exchange resin tower. The inlet flow rate in the test pipeline is 10 L / h, and the inlet pressure is 0.3 MPa. The melt-blown filter cartridge is made of polypropylene fiber with a filtration accuracy of 5 μm. The activated carbon filter contains granular activated carbon with an iodine adsorption value of 1000 mg / g. The two-stage reverse osmosis membranes both have a filtration accuracy of 0.1 μm, with an inlet pressure of 0.6 MPa. The first-stage reverse osmosis membrane has a permeate rate of 75%, and the second-stage reverse osmosis membrane has a permeate rate of 85%. The ion exchange resin tower has a cation exchange resin to anion exchange resin mass ratio of 3:2 and a flow rate of 50 BV / h. The effluent from these steps enters the TOC online analyzer.

[0050] Step 3: At a certain moment, the online TOC analyzer detects a TOC concentration of 190 μg / L. Based on the predefined linear relationship between the TOC detection range of 0–200 μg / L and the current signal of 4–20 mA, the online TOC analyzer outputs a corresponding current intensity signal (17.3 mA) to the PLC control box. A bromide and oxidant reaction system is used to remove small molecule organic matter. The bromide is NaBr, the oxidant is NaClO, and the reducing agent is NaHSO3. The relationship between the reagent dosage and the TOC concentration is as follows:

[0051] C NaBr =1000x3 +5x 2 +20x+7.9

[0052] C NaClO =0.4C NaBr

[0053] C NaHSO3 =084C NaClO +5

[0054] In the formula, x is the TOC value after detection pretreatment, in mg / L, and C NaBr C NaClO C NaHSO3 All units are mg / L;

[0055] Step 4: The PLC control box calculates the dosage of each agent according to the above formula (NaBr is 18.7 mg / L, NaClO is 7.5 mg / L, and NaHSO3 is 11.3 mg / L). Based on the predefined linear relationship between the dosage of 0-50 mg / L and the current signal of 4mA-20mA, it converts the dosage into current signals (NaBr is 10.0mA, NaClO is 6.4mA, and NaHSO3 is 7.6mA) and transmits them to the dosing pumps. Based on the predefined linear relationship between the dosing pump opening of 0%-100% and the current signal of 4mA-20mA, the NaBr dosing pump is opened at 37% for dosing, the NaClO dosing pump is opened at 15% for dosing, and the NaHSO3 dosing pump is opened at 22% for dosing.

[0056] Step 5: After 2 minutes, the TOC online analyzer detected a TOC concentration of 110 μg / L. Based on the predefined linear relationship between the TOC detection range of 0–200 μg / L and the current signal of 4–20 mA, the TOC online analyzer outputs a corresponding current intensity signal (11.8 mA) to the PLC control box. The same bromide and oxidant reaction system is used to remove small molecule organic matter. The bromide is NaBr, the oxidant is NaClO, and the reducing agent is NaHSO3. The relationship between the reagent dosage and the TOC concentration is the same as in Step 3.

[0057] Step 6: The PLC control box calculates the dosage of each agent (NaBr 11.5 mg / L, NaClO 4.6 mg / L, NaHSO3 8.9 mg / L). Based on the predefined linear relationship between the dosage of 0-50 mg / L and the current signal of 4mA-20mA, it converts the dosage into current signals (NaBr 7.7mA, NaClO 5.5mA, NaHSO3 6.8mA) and transmits them to the dosing pumps. Based on the predefined linear relationship between the dosing pump opening of 0%-100% and the current signal of 4mA-20mA, the NaBr dosing pump is opened at 23% for dosing, the NaClO dosing pump at 9% for dosing, and the NaHSO3 dosing pump at 17% for dosing.

[0058] Repeat steps 5-6. The online TOC analyzer promptly converts the monitored TOC concentration into a current signal and transmits it to the PLC control box. The PLC control box calculates the required dosage for each dosing pump based on the TOC concentration and converts the dosage into a current signal, which is then transmitted to the dosing pump. The dosing pump converts the current signal into the corresponding opening degree to perform dosing, thereby completing the effective control of small molecule organic matter in the ultrapure water preparation system.

[0059] The relationship between the change in the content of small molecule organic matter in the raw water and the fluctuation of TOC in the terminal effluent of the ultrapure water preparation system containing the monitoring and control system of this invention is as follows: Figure 4 As shown, from Figure 4 It can be seen that changes in the content of small molecule organic matter in the raw water have no impact on the TOC of the final effluent.

[0060] Example 2

[0061] A semiconductor factory uses recycled water from treated wastewater as raw material for its ultrapure water preparation system. The final TOC requirement is less than 0.5 μg / L. However, due to the influence of process chemicals used in the production line, such as isopropanol and acetone, the content of small molecule organic matter (as TOC) in the recycled water fluctuates between 20 μg / L and 200 μg / L.

[0062] This embodiment removes small molecule organic matter by adding H2O2 to a vacuum ultraviolet oxidation device after the first-stage reverse osmosis permeate tank. The specific implementation steps of the monitoring and control system of this invention are as follows:

[0063] Step 1: Draw test water at a flow rate of 30L / h from the raw water tank of the ultrapure water preparation system and deliver it to the melt-blown filter cartridge via the test booster pump;

[0064] Step 2: The test water passes through a melt-blown filter, an activated carbon filter, a two-stage reverse osmosis membrane, and an ion exchange resin tower. The inlet flow rate of the test pipeline is 30 L / h, and the inlet pressure is 0.6 MPa. The melt-blown filter cartridge is made of polypropylene fiber with a filtration accuracy of 1 μm. The activated carbon filter contains granular activated carbon made from coconut shells, with an iodine adsorption value of 1500 mg / g. The two-stage reverse osmosis membrane has a filtration accuracy of 0.08 μm, with an inlet pressure of 0.5 MPa. The first-stage reverse osmosis membrane has a permeate rate of 85%, and the second-stage reverse osmosis membrane has a permeate rate of 90%. The ion exchange resin tower has a cation exchange resin to anion exchange resin mass ratio of 3:2 and a flow rate of 75 BV / h. The effluent from the test pipeline enters the TOC online analyzer.

[0065] Step 3: At a certain moment, the TOC online analyzer detects a TOC concentration of 151 μg / L. Based on the predefined linear relationship between the TOC detection range of 0–200 μg / L and the current signal of 4–20 mA, the TOC online analyzer outputs a corresponding current intensity signal of 14.6 mA to the PLC control box. In Example 2, a reaction system for activating H2O2 with a medium-low pressure vacuum ultraviolet lamp is used to remove small molecule organic matter. The reducing agent is NaHSO3, and the ultraviolet lamp irradiation wavelength is a combination of 185 nm (10%) and 254 nm (90%), with a radiation illuminance of 11400 μW / cm². 2 Construct a formula relating the dosage of the drug to the TOC concentration:

[0066] C H2O2 =10x 3 +4x 2 +7.6x+12

[0067] C NaHSO3 =2.45 H2O2

[0068] In the formula, x is the TOC value after detection pretreatment, in mg / L, and C H2O2 With C NaHSO3 All units are mg / L;

[0069] Step 4: The PLC control box calculates the dosage of each agent according to the above formula (H2O2 is 13.3 mg / L, NaHSO3 is 32.5 mg / L). Based on the predefined linear relationship between the dosage of 0-50 mg / L and the current signal of 4mA-20mA, it converts the dosage into a current signal (H2O2 is 8.3mA, NaHSO3 is 14.4mA) and transmits it to the dosing pump. Based on the predefined linear relationship between the dosing pump opening of 0%-100% and the current signal of 4mA-20mA, the H2O2 dosing pump is opened at 27% and the NaHSO3 dosing pump is opened at 65%.

[0070] Step 5: After 2 minutes, the TOC online analyzer detected a TOC concentration of 78 μg / L. Based on the predefined linear relationship between the TOC detection range of 0–200 μg / L and the current signal of 4–20 mA, the TOC online analyzer outputs a corresponding current intensity signal of 9.7 mA to the PLC control box. Similarly, a low-to-medium pressure vacuum ultraviolet lamp is used to irradiate and activate the H2O2 reaction system to remove small molecule organic matter. The reducing agent is NaHSO3, and the ultraviolet lamp irradiation wavelength is a combination of 185 nm (10%) and 254 nm (90%), with a radiation illuminance of 11400 μW / cm². 2 The relationship between the dosage of the drug and the TOC concentration is the same as in step three.

[0071] Step 6: The PLC control box calculates the dosage of each agent (H2O2 is 12.6 mg / L, NaHSO3 is 31.0 mg / L). Based on the predefined linear relationship between the dosage of 0-50 mg / L and the current signal of 4mA-20mA, it converts the dosage into a current signal (H2O2 is 8.0mA, NaHSO3 is 13.9mA) and transmits it to the dosing pump. Based on the predefined linear relationship between the dosing pump opening of 0%-100% and the current signal of 4mA-20mA, the H2O2 dosing pump is opened at 25% and the NaHSO3 dosing pump is opened at 61%.

[0072] Repeat steps 5-6. The online TOC analyzer promptly converts the monitored TOC concentration into a current signal and transmits it to the PLC control box. The PLC control box calculates the required dosage for each dosing pump based on the TOC concentration and converts the dosage into a current signal, which is then transmitted to the dosing pump. The dosing pump converts the current signal into the corresponding opening degree to perform dosing, thereby completing the effective control of small molecule organic matter in the ultrapure water preparation system.

[0073] Two identical ultrapure water preparation systems were selected and the same raw water was introduced simultaneously. One ultrapure water preparation system was introduced with a detection pipeline containing the monitoring and control system of this invention, while the other ultrapure water preparation system was not introduced with a detection pipeline containing the monitoring and control system of this invention. The TOC values ​​of the terminal effluent of the two ultrapure water preparation systems are shown in Table 1.

[0074] Table 1

[0075]

[0076] Table 1 shows that there is a positive correlation between the small molecule organic matter in the raw water and the final TOC. After the detection pipeline containing the monitoring and control system of this invention is introduced, the TOC of the final product water of the ultrapure water preparation system can be stably maintained at less than 0.5 μg / L, achieving stable compliance with the TOC standard of the final product water even under fluctuations in the raw water TOC.

Claims

1. A monitoring and control system for the content of small molecule organic matter in raw water, characterized in that: The monitoring and control system includes a detection pipeline, an online TOC analyzer, and a PLC control box. The online TOC analyzer, as well as the oxidant and reductant dosing pumps of the ultrapure water preparation system, are all connected to the PLC control box. The detection pipeline extends from the outlet of the raw water tank and sequentially includes a melt-blown filter, an activated carbon filter, a two-stage reverse osmosis membrane, and an ion exchange resin tower. The effluent from the ion exchange resin tower enters the online TOC analyzer for TOC concentration detection. The online TOC analyzer transmits the obtained TOC concentration as a 4–20 mA current signal to the PLC control box. The PLC control box converts the received current signal into the required dosage for the corresponding TOC concentration and then feeds it back to the oxidant and reductant dosing pumps as a 4–20 mA current signal. By adjusting the pump opening, the required amounts of oxidant and reductant are added to the advanced oxidation unit of the ultrapure water preparation system. The flow ratio between the inlet flow of the detection pipeline and the outlet flow of the raw water pipeline is 1:100–1000. The monitoring and control system has a separate detection pipeline led out from the outlet pipeline of the raw water tank of the ultrapure water preparation system. It can detect changes in the concentration of neutral small molecule organic matter in the raw water in a timely manner and adopt a precise dosing method calculated by fitting, thereby significantly reducing the impact of fluctuations in the concentration of neutral small molecule organic matter in the raw water on the TOC of the terminal water of the ultrapure water preparation system, and thus ensuring that the quality of the terminal water meets the standards.

2. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 1, characterized in that: The meltblown filter cartridge is made of polypropylene fiber material with a filtration accuracy of 1μm to 5μm; the activated carbon filter is filled with granular activated carbon with an iodine adsorption value of 1000mg / g to 1800mg / g.

3. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 1, characterized in that: Both reverse osmosis membranes are made of polyamide, with a filtration accuracy of 0.05μm to 0.1μm and an inlet pressure of 0.5MPa to 0.7MPa.

4. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 1, characterized in that: The cation exchange resin in the ion exchange resin tower is a sulfonic acid gel type, and the anion exchange resin is a quaternary ammonium gel type. The mass ratio of the two resins is 3:2, and the flow rate is 50 BV / h to 85 BV / h.

5. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 1, characterized in that: The inlet water flow rate of the testing pipeline is 10L / h to 30L / h, and the inlet water pressure is 0.3MPa to 0.6MPa.

6. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 1, characterized in that: The relationship between TOC concentration and the dosage of oxidant and reducing agent is as follows: In the reaction system of bromide salt and oxidant C1=ax 3 +bx 2 +cx+d (1) C2 = eC1 (2) In the formula, x is the TOC value of the effluent after treatment by the detection pipeline detected by the TOC online analyzer; a to g are chemical reaction coefficients, with values ​​of: a: 1000–2000, b: 5–6, c: 20–80, d: 7.9–8.5, e: 0.4–0.5, f: 0.6, g: 5–10; C1 is the concentration of bromide added to the system; C2 is the concentration of oxidant added to the system; C3 is the concentration of reductant added to the system; and M2 and M3 are the relative molecular masses of the oxidant and reductant, respectively.

7. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 6, characterized in that: In the reaction system of bromide and oxidant, the bromide is NaBr or KBr, the oxidant is one or more of NaClO, O3 or H2O2, and the reducing agent is NaHSO3.

8. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 1, characterized in that: The relationship between TOC concentration and the dosage of oxidant and reducing agent is as follows: In the UV-activated oxidant reaction system C4=hx 3 +ix 2 +jx+k (4) In the formula, x is the TOC value of the effluent after treatment by the detection pipeline detected by the TOC online analyzer; h to m are chemical reaction coefficients, with values ​​of: h: 1 to 10, i: 4 to 8, j: 7.6 to 10, k: 12 to 50, l: 0.8, m: 0 to 10; C4 is the concentration of oxidant added to the system; C5 is the concentration of reductant added to the system; and M4 and M5 are the relative molecular masses of the oxidant and reductant, respectively.

9. The monitoring and control system for the content of small molecule organic matter in raw water according to claim 8, characterized in that: In the UV-activated oxidant reaction system, the oxidant is one or more of H2O2, NaClO, Na2S2O8 or KHSO5; a medium-pressure / low-pressure UV lamp is used to activate the oxidant, with a light wavelength range of 185nm to 300nm; the reducing agent is NaHSO3.

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