WO2012122892A1

WO2012122892A1 - Off-line cleaning and repairing method for different fouling of waste reverse osmosis membrane

Info

Publication number: WO2012122892A1
Application number: PCT/CN2012/071724
Authority: WO
Inventors: 邓茂林; 谭鸿波; 朱仲强
Original assignee: 四川科伦药业股份有限公司
Priority date: 2011-03-14
Filing date: 2012-02-28
Publication date: 2012-09-20
Also published as: CN102210978A; WO2012122890A2; CN102210978B

Abstract

An off-line cleaning and repairing method for waste reverse osmosis membrane comprises the following steps: (1) analyzing the components of the fouling of the waste reverse osmosis membrane; (2) cleaning or repairing the membrane using acid or basic cleaning reagent and repairing reagent for different membrane fouling by using waste reverse osmosis cleaning and repairing equipment according to the analysis result; (3) continuously measuring the correlated parameter of the membrane performance in the chemic cleaning and repairing process. The parameters of the membrane cleaned and repaired by the method approaches those of the new membrane, the repairing ratio of the membrane is greatly increased and the pertinence of the method is improved, meanwhile the chemic damage by the existing cleaning methods is avoided.

Description

Description of the method for off-line cleaning and repair of membrane fouling of different waste reverse osmosis membranes

The invention relates to a method for cleaning and repairing a waste reverse osmosis membrane in an off-line state.

Background technique

At present, reverse osmosis technology is adopted for the preparation of purified water in various fields (food, pharmaceutical, electric power, tap water, etc.). The reverse osmosis membrane is the core of the reverse osmosis system, and its excellent performance directly affects the performance of the reverse osmosis system.

After the reverse osmosis system is operated for a period of time, the surface of the membrane will form insoluble bacteria layer, metal scale, silicon scale and other organic and inorganic pollutants, which will increase the inlet pressure of the reverse osmosis system, decrease the water production, and increase the conductivity of the water. Water quality, reverse osmosis membrane consumption is extremely high.

According to the current technology, most of the waste reverse osmosis membranes are treated with simple online cleaning technology. In this way, for a plurality of membranes in a plurality of membrane tubes, a membrane blockage must be performed on all membranes (including still normal membranes). Chemical cleaning, which produces unnecessary chemical damage to the membrane with good function. The prior art does not conduct professional analysis on different scaling conditions and water quality, nor does it conduct professional chemical analysis for different scales, giving a special formula. This will result in a rougher film cleaning method, which is difficult to guarantee after cleaning.

Based on the analysis of waste reverse osmosis membrane and membrane scale, it is found that the desalination performance of reverse osmosis membrane is seriously degraded, and the reverse osmosis membrane may be worn.

? L phenomenon, the surface of the reverse osmosis membrane was chemically repaired to achieve a significant increase in membrane desalination performance requirements. At present, the prior art does not involve a repair method for a damaged membrane, and the research here is still blank.

Summary of the invention

The object of the present invention is to disclose a targeted off-line cleaning and repairing method for a waste reverse osmosis membrane obtained by professional analysis of different fouling conditions and water quality.

The object of the present invention is achieved by the following scheme:

A method for off-line cleaning and repair of off-line cleaning and repairing reagents for different waste reverse osmosis membrane scales, which comprises the following steps:

(1) Analysis of the scale component of the waste reverse osmosis membrane, the steps are as follows: First, the sample of the retentate on the surface of the waste reverse osmosis membrane is collected, and the sample of the retentate is identified by chemical analysis, scanning electron microscopy (SEM) analysis and X-ray diffractometer respectively. Characterizing and analyzing the scale formed in the waste reverse osmosis membrane, confirming that the pollution type is silicate, carbonate and/or iron oxide; secondly, the membrane scale of different pollution types is analyzed by three chemical methods and Determination, the composition of the scale component of the waste reverse osmosis membrane is obtained; finally, when the chemical analysis cannot be performed, the color and density of the residue on the reverse osmosis membrane are tested by the SDI meter to judge the classification of the dirt, and finally the waste reverse osmosis membrane is obtained. Membrane composition analysis results;

(2) According to the results of the analysis of the scale component of the waste reverse osmosis membrane, using the waste reverse osmosis membrane cleaning and repairing equipment (see Fig. 8), using the waste reverse osmosis membrane cleaning agent and the repairing agent of the present invention for the above different membrane scales, High-speed cleaning at a liquid flow rate of 10 m I seconds, and repairing under a pressure of 5 Mpa;

(3) Determination of the relevant parameters of the membrane performance in the chemical cleaning, chemical repair process, the measurement conditions are: the medium is tap water with a conductivity of 450-550 ys / cm, the measured pressure is 1. 5MPa, the measured temperature is the tap water temperature is normal temperature , cleaning and repair to meet the eligibility criteria: desalting Description

2MPa。 The rate of water is more than 15%, the water recovery rate is more than 12%, the pressure difference is less than 0. 2MPa.

Wherein, the color and density of the residue on the reverse osmosis membrane tested by the SDI meter are classified as: the brown residue is iron scale; the white residue is silicon, sandy clay, calcium scale; the lens shape is inorganic Colloid, calcium scale; Judging from the odor and the shape of the contaminant, it also contains bio- or organic dirt.

Wherein, the membrane performance related parameters, including salt removal rate, water recovery rate, pressure difference, calculation method is salt removal rate = (Ei-Eo) / Ei, water recovery rate _{= Vo} / _Vi , pressure difference _{= Pi} -p ₀ , wherein, the conductivity of the water in the Ei-reverse osmosis membrane; the fresh water conductivity of the Eo-reverse osmosis membrane; the fresh water flow rate of the Vo-reverse osmosis membrane; the influent flow rate of the Vi-reverse osmosis membrane; Pi-reverse osmosis The inlet inlet pressure of the membrane; the concentrated outlet pressure of the Po-reverse osmosis membrane.

Wherein, the method for determining the eligibility criteria is:

(1) In the cleaning and repairing process, in the tap water having a conductivity of 450-550 ws / cm, the measured pressure is 1. 5MPa, and the measured temperature is the tap water temperature, that is, the normal temperature condition, respectively, and the new reverse osmosis membrane and the waste anti-separation are respectively determined. Various performance parameters of the permeable membrane;

(2) Comparing the measured parameters, the main differences are as follows: 1 The pressure difference is increased, the pressure difference of the new reverse osmosis membrane is 0. IMPa, and the initial pressure difference of the waste reverse osmosis membrane is much higher than 0. 2MPa; 2 water recovery rate decreases, the water recovery rate of the new reverse osmosis membrane is 15%, and the water recovery rate of the waste reverse osmosis membrane is 10%; 3 the salt removal rate decreases; the new membrane salt removal rate is generally greater than 99%, The demineralization rate of waste reverse osmosis membranes decreases a lot, generally less than 80%;

(3) Washing separately for various scales, and measuring various parameters under the same test conditions;

(4) Comparing the performance of the cleaned reverse osmosis membrane with the new reverse osmosis membrane, and demarcating each parameter until the performance of the two is equivalent, the qualification criteria for the cleaning and repair of the waste reverse osmosis membrane of the present invention are established: 2MPa。 The water removal rate of more than 0. 2MPa.

Wherein, the waste reverse osmosis membrane cleaning and repairing device may be as follows:

The device is mainly composed of a wide door, a flow meter, a conductivity meter, a pressure gauge and a water inlet pH, a pressure pump P and a precision filter PP1 and PP2, which are emptied by a filter core V0, a water valve VI, and a tap water. Inlet l V2, tap water outlet | V3, acid lotion influx l V4, alkaline lotion inlet valve V5, repair agent inlet 闽V6, total inlet valve V7, old membrane inlet V8, old membrane concentrated water Exit 闽V9, old membrane short-circuit valve V10, pure water-new membrane inlet valve VI I, old membrane fresh water outlet valve V12, new membrane inlet water f« V13, new membrane concentrated water outlet Gang V14, new membrane short-circuit valve V15 , fresh water discharge valve V16, concentrated water discharge valve V17, repair agent concentrated water return valve V18, repair agent fresh water return valve V19, alkali washed concentrated water return valve V20, alkaline washed fresh water return W V21, pickled fresh water return valve V22, acid The concentrated water return valve V23, the concentrated water check valve V24, V25, V26, V27, and the waste liquid discharge wide V28; the flow meter consists of the old membrane inlet flow meter Fl, the new membrane inlet flow meter F2, the old membrane Fresh water flow meter F3 and new membrane light 7J flow meter F4; the conductivity It consists of old membrane water conductivity meter El, new membrane water conductivity meter E2 and old membrane fresh water conductivity meter E3; the pressure gauge consists of inlet water total pressure gauge Pl, new membrane inlet water pressure gauge P2 and new membrane Export pressure gauge P3;

The inlet of the precision filter PP1 is connected to the municipal water pipe through the tap water valve, and the outlet is connected to the inlet of the water tank 1 through the tap water inlet valve V2. The tap water tank 1, the pickling tank 2, the caustic washing tank 3, and the repairing tank 4 outlet respectively pass through the tap water. Export | V3, acid detergent inlet valve V4, alkaline detergent inlet valve V5, repair agent inlet valve V6 and pressure pump 5 inlet, intermediate connection of old membrane inlet conductivity meter El, into Description

The water meter pH, the outlet of the pressure pump 5 is connected to the inlet of the waste R0 membrane 6 through the total inlet water V7, the old membrane inlet valve V8, the old membrane inlet flow meter F1, and the old membrane short-circuit valve V10, the new membrane. Water flow meter F2, new membrane inlet valve V13 is connected with the inlet of new membrane 7, the middle of the new membrane inlet pressure gauge P2, the new membrane inlet conductivity meter E2, the waste R0 membrane 6 concentrated water outlet through the old membrane concentrated water Export 闽V9, new membrane inlet flowmeter F2, new membrane inlet water l V13 is connected with the inlet of new membrane 7, the middle membrane is connected with new membrane inlet pressure gauge P2, new membrane inlet conductivity meter E2, and short circuit through new membrane Valve V15 is connected to PP2 precision filter inlet, waste R0 membrane fresh water outlet through old membrane fresh water outlet valve V12, old membrane fresh water flowmeter F3, repairing fresh water return valve V19, alkaline washing fresh water return valve V21, pickling fresh water return valve V22 It is connected with the repair agent tank 4, the alkali washing tank 3, the pickling tank 2 inlet, the old membrane fresh water conductivity meter E3, the end of the fresh water discharge V16, and the pure water-new membrane water inlet VI I Connected to the inlet of the new membrane 7, the new R0 membrane 7 is concentrated Through the new membrane concentrated water outlet pottery V14, concentrated water check valve V24 and the precision filter PP2 inlet, the middle of the new membrane outlet pressure gauge P3, the new R0 membrane 7 fresh water outlet through the new membrane freshwater flowmeter F4, repair agent fresh water The side return valve V19, the alkaline washed fresh water reflux l V21, and the pickled fresh water return valve V22 are respectively connected with the repair agent tank 4, the alkali washing tank 3, the pickling tank 2 inlet, and the end is connected with the fresh water discharge valve V16, and the PP2 precision filter outlet is passed. The repairing agent concentrated water returning V18, alkali washing concentrated water return valve V20, pickling concentrated water return valve V23 are respectively connected with the repairing agent tank 4, the alkali washing tank 3, the pickling tank 2 inlet, and the end is connected with concentrated water to discharge l V17.

The invention discloses an off-line cleaning and repairing method and reagent for waste reverse osmosis membrane, and performs targeted cleaning and repairing on different kinds of reverse osmosis membrane scales, and solves the problem of incomplete cleaning caused by the original rough cleaning method, and is groundbreaking. The research and development of repairing reagents and methods for damaged membranes have filled the domestic gap in this respect. The parameters of the membrane obtained by the method and the reagent cleaning and repairing are closer to the new membrane, the membrane repair rate is greatly enhanced, the pertinence is higher, and the disadvantages of the chemical damage of the intact membrane in the existing cleaning method are avoided. The method and the reagent for cleaning and repairing the waste reverse osmosis membrane of the invention can ensure the performance of the membrane after cleaning is close to or close to the new membrane, greatly reducing the cost of the membrane consumption of the enterprise, ensuring that the production and membrane cleaning do not affect each other, and eliminate the online chemistry. Wash damage to normal membranes.

Effect of various metal ions on the performance of repair agent MXFJ-400

(1) UV characterization of solutions before and after repairing used reverse osmosis membranes with MXFJ-400

The solution before and after repairing the waste reverse osmosis membrane with MXFJ-400 was subjected to UV characterization, and the results are shown in Fig. 3. It can be seen from the ultraviolet spectrum that the MXFJ-400 has two maximum absorption peaks at 213 nm and 272 nm before repairing the waste reverse osmosis membrane, and the absorption peak at 213 is higher than the absorption peak at 272 nm; the remaining after repairing the waste reverse osmosis membrane The MXFJ-400 solution also had a maximum absorption peak at 213 ηηη and 272 nm, but its ultraviolet absorption at 213 nm became small, and the ultraviolet absorption at 272 ηηη became large. Some common metal ions were added to the MXFJ-400 aqueous solution to investigate the effect of common metal ions on the MXFJ-400.

(2) Investigate the effects of various ions on the repair agent MXFJ-400

Effect of Fe ³⁺ on MXFJ-400 Fe ³⁺ was added to MXFJ-400 aqueous solution, and it was found that the original colorless and transparent MXFJ-400 aqueous solution turned brown. Ultraviolet spectroscopy was performed on different amounts of MXFJ-400 solution. As shown in Fig. 4, it can be seen from the spectrogram that the UV absorption peak of MXFJ-400 was significantly red-shifted after adding Fe ³⁺ , and in 213 dishes and 272 mn. The UV absorption at the site is greatly reduced; this shows that MXFJ-400 has a strong Fe ³⁺ If the film surface contains a large amount of Fe ³⁺ , the effective concentration of MXFJ-400 will be drastically reduced during chemical repair, resulting in a decrease in its repair ability. Therefore, in the process of repairing the waste reverse osmosis membrane, it is necessary to thoroughly clean the iron scale on the surface of the membrane, and the water for preparing the repair solution is also subjected to the treatment of Fe ³⁺ .

The effect of Al ³⁺ on MXFJ-400 was added to Al ³⁺ , and the mixture was subjected to ultraviolet spectrum scanning. The result is shown in Figure 5. It can be seen from the figure that after the addition of Al ^{3+ to} MXFJ-400, the maximum absorption peak of ultraviolet light is significantly red-shifted, while the ultraviolet absorption at 213 nm and 272 dishes is lowered. This indicates that MXFJ-400 has a chelation effect on Al ³⁺ . The presence of Al ³⁺ also causes the effective concentration of MXFJ-400 to decrease. Therefore, the water prepared for MXFJ-400 needs to be treated with Al ³⁺ , and the A1 scale on the surface of the waste reverse osmosis membrane needs to be completely removed before cleaning.

Effect of Ca ²⁺ on MXFJ-400 Ca ²⁺ was added to MXFJ-400 aqueous solution, and the mixed solution was subjected to ultraviolet spectrum scanning. The results are shown in Fig. 6. It can be seen from the figure that the red absorption of the ultraviolet absorption peak does not occur after the addition of Ca ²⁺ in MXFJ-400, and the ultraviolet absorption intensity at 213 nm and 272 nm remains substantially unchanged. This indicates that Ca ²⁺ has little effect on MXFJ-400, and the influence of Ca ²⁺ can be ignored when formulating MXFJ-400.

Effect of Zn ²⁺ on MXFJ-400 Zn ²⁺ was added to MXFJ-400 aqueous solution, and the mixed solution was subjected to ultraviolet spectrum scanning. The results are shown in Fig. 7. It can be seen from the figure that the maximum absorption peak of MXFJ-400 does not change after the addition of Zn ²⁺ . In addition, MXFJ-400 has enhanced UV absorption at 213 and 272 nm. This indicates that Zn ²⁺ has synergistic effect on MXFJ-400, and Zn ²⁺ activates MXFJ-400 to a certain extent, so that the effective concentration of MXFJ-400 is improved. Therefore, Zn ²⁺ can be added during the repair of waste reverse osmosis to improve the repairing ability of MXFJ-400.

The invention studies the performance of the repairing agent MXFJ-400, and when using the same to repair the waste reverse osmosis membrane, the Fe and A1 scales on the surface of the membrane need to be removed first, and the solvent for preparing the repairing agent also needs to be removed. Fe ³⁺ and A1 ^3+, Ca ²⁺ has little influence on the repair agent, can increase the ability of Zn ²⁺ repair agent, during the reverse osmosis membrane repair inch Zn ²⁺ may be added to the repair agent.

DRAWINGS

Figure 1. Magnification of the crystal structure of the membrane scale 1000 times;

Figure 2. Magnification of the crystal structure of the membrane scale 5000 times;

Figure 3. UV spectrum of the MXFJ-400 before and after repairing the reverse osmosis membrane;

Figure 4. Ultraviolet spectrum of Fe ³⁺ added to MXFJ-400; Figure 5. Ultraviolet spectrum of Al ³⁺ added to MXFJ-400; Figure 6. Ultraviolet spectrum of Ca ²⁺ added to MXFJ-400; Figure 7. Ultraviolet spectrum of Zn ²⁺ added to MXFJ-400;

Figure 8. Structure diagram of the waste reverse osmosis membrane cleaning and repair equipment;

In the figure: filter vent valve V0, water valve VI, tap water inlet valve V2, tap water outlet valve V3, acid detergent inlet valve V4, alkaline detergent inlet valve V5, repair fluid inlet valve V6, total water Valve V7, old membrane inlet water V8, old membrane concentrated water outlet V9, old membrane short-circuit valve V10, pure water-new membrane inlet valve VI I, old membrane freshwater outlet valve V12, new membrane inlet water V13, New membrane concentrated water outlet | V14, new membrane short circuit | V15, fresh water discharge valve V16, concentrated water discharge valve V17, repair agent concentrated water return valve V18, repair agent fresh water return valve V19, alkali washed concentrated water reflux 闽V20, alkaline washing Fresh water return V21, pickled fresh water return valve V22, pickled concentrated water return V23, concentrated water check valve V24, V25, V26, V27, waste liquid discharge valve V28, old membrane inlet flow meter Fl, new membrane Water flow meter F2, old film fresh water flow meter F3, new membrane fresh water flow meter F4, old membrane water conductivity meter El, new membrane water conductivity meter E2, old membrane fresh water conductivity meter E3, water meter pH, Pressure pump P, water inlet pressure gauge Pl, new membrane inlet pressure gauge P2, new P3 outlet pressure gauge, precision filter PP1 and PP2, a water tank, tank 2 pickling, alkaline cleaning tank 3, 4 agent tank repair.

detailed description

Example 1

(1) The scale component analysis of No. 25 waste reverse osmosis membrane of model CPA3-8080 produced by Nitto Denko Co., Ltd. is as follows: First, the sample of the retentate on the surface of the waste reverse osmosis membrane is collected, respectively, by chemical analysis method, Scanning electron microscopy (SEM) and X-ray diffractometry were used to identify the retentate samples. The crystal structure of the scale was shown in Fig. 1 and Fig. 2. Characterize and analyze the scale formed in the waste reverse osmosis membrane, confirm that the pollution type is silicate and/or carbonate; secondly, the membrane scale of different pollution types is analyzed and measured by three chemical methods, and the waste is obtained. The composition of the scale component of the reverse osmosis membrane; Finally, when the chemical analysis cannot be performed, the color and density of the residue on the reverse osmosis membrane are measured by the SDI meter to determine the classification of the dirt. The white residue is silicon, sandy clay, and calcium scale. The shape of the lens is inorganic colloid and calcium scale. The result of the analysis of the scale composition of the waste reverse osmosis membrane is that the main component of the membrane scale is Si0 ₂ , and also contains illite, mica stone and oblique chlorite, mainly composed of Si, K, Ca, Mg, Al elements;

(2) According to the results of the analysis of the scale component of the waste reverse osmosis membrane, using the waste reverse osmosis membrane cleaning and repairing equipment shown in Fig. 8 of the specification, using the cleaning agent and the repairing agent of the present invention for different membrane scales, in the liquid The high-speed cleaning is carried out at a flow rate of 10 m / sec, and repaired under a pressure of 1.5 Mpa;

(3) Determine the relevant parameters of membrane performance during chemical cleaning and chemical repair, including salt removal rate, water recovery rate, and pressure difference. The calculation method is:

Demineralization rate = (Ei-Eo ) / Ei,

Water recycling Description

Pressure difference = Pi - Po,

Among them, the influent conductivity of Ei-reverse osmosis membrane; the fresh water conductivity of Eo-reverse osmosis membrane; the fresh water flow of Vo-reverse osmosis membrane; the influent flow of Vi-reverse osmosis membrane; the influent of Pi-reverse osmosis membrane Inlet pressure; concentrated outlet pressure of the Po-reverse osmosis membrane.

The measurement conditions are as follows: The medium is tap water having a conductivity of 450-550 μs 1 cm, and the measurement pressure is 1.5 MPa, and the measurement temperature is the tap water temperature, that is, normal temperature.

The various parameters obtained by measurement are shown in Table 1. The initial pressure difference of the membrane before washing was 1.25 MPa, and the membrane was blocked, and its initial desalination performance could not be determined. First, the reverse rinsing is performed, and the flow path of the membrane is opened. Subsequently, it was cleaned using Formulation 1, and the pressure difference was gradually decreased to 0.17 MPa, and the salt removal rate and water recovery rate were 71.9% and 11.4%, respectively. After that, it is cleaned by formula three, mainly to remove organic matter, colloid, and SiO ₂ on the surface of the film. After washing, the salt removal rate dropped to 69.9%, the water recovery rate increased to 19.2%, and the pressure difference dropped to 0.15 MPa. After repeated cleaning of Formulation 1 and Formula 3, the repair agent was finally used for chemical repair to achieve a salt removal rate of 86.9%, a water recovery rate of 13.8%, and a pressure difference of 0.15 ΜΡβ.

Table No. 1.25 membrane cleaning reagents and parameters

The method for determining the eligibility criteria for the cleaning of used reverse osmosis membranes is

(1) During the cleaning and repairing process, in the tap water with a conductivity of 450-550μs/cm, the measured pressure is 1.5MPa, and the measured temperature is the tap water temperature, ie, the normal temperature condition, and the new reverse osmosis membrane and the waste reverse osmosis are respectively determined. The performance parameters of the membrane, the salt removal rate is 99.5

%, the fresh water conductivity is 2.51 s cm- ¹ , the water recovery rate is 17.9%, the water permeability is 40.3M ³ d ¹ , and the pressure difference is 0.07 MPa.

(2) Comparing the measured parameters, the main differences are: 1 The pressure difference is increased, the pressure difference of the new reverse osmosis membrane is about 0. IMPa, and the initial pressure difference of the waste reverse osmosis membrane is much higher than 0.2. MPa; 2 water recovery rate decreases, the water recovery rate of the new reverse osmosis membrane is about 15%, and the water recovery rate of the reverse I membrane is much lower than this value; 3 the salt removal rate decreases. The salt removal rate of the new membrane is generally greater than 99%, while the salt removal rate of the waste reverse osmosis membrane is much lower.

(3) Washing is performed for each different type, and the parameters are measured under the same test conditions. Instruction manual

(4) Compare the performance of the cleaned reverse osmosis membrane with the new reverse osmosis membrane, and demarcate the parameters until the performance of the two is equivalent. The qualification criteria for the cleaning of the waste reverse osmosis membrane are as follows: The rate is above 85.0%, the water recovery rate is above 12%, and the pressure difference is less than 0.2MPa.

All the parameters measured after the above cleaning and repair have reached the cleaning qualification standard, and the performance of the used reverse osmosis membrane is basically close to that of the new membrane. Example 2:

The No. 5 waste reverse osmosis membrane of Model No. BW30-400 produced by The Dow Chemical Company was subjected to the method and procedure of Example 1 to analyze the scale composition, first confirming that the type of pollution is silicate and/or carbonate; The membrane scales of different types of pollution are analyzed and determined by three chemical analysis methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained. Finally, when the chemical analysis cannot be performed, the residue on the reverse osmosis membrane is tested by the SDI instrument. Color, density, judging dirt classification, white residue is silicon, sandy clay, calcium scale; crystal shape is calcium scale; finally, the result of membrane scale composition analysis of waste reverse osmosis membrane is that the main component of membrane scale is Si0 ₂ , Containing illite, mica stone and oblique chlorite, mainly composed of Si, K, Ca, Mg, Al elements;

(2) According to the results of the analysis of the scale component of the waste reverse osmosis membrane, the waste reverse osmosis membrane cleaning and repairing equipment shown in Fig. 8 of the specification is used, and the cleaning agent and the repairing agent of the present invention for different membrane scales are used, in the liquid High-speed cleaning at a flow rate of ⁄3⁄410 m/s, and repair under pressure; 51.5 MPa;

Demineralization rate = (Ei-Eo) /Ei,

Water recovery rate = \3⁄4/ Vi,

Pressure difference = Pi-Po,

The measurement conditions are as follows: The medium is tap water having a conductivity of 450-550 s/cni, and the measurement pressure is 1.5 MPa, and the measurement 1 temperature is tap water, that is, normal temperature.

The various parameters measured are shown in Table 2. The initial salt removal rate of the film was 96.6%, the fresh water conductivity was 17.6%, and the pressure difference was 0.20 MPa. After the first and third repeated cleaning and chemical repair treatment of the repairing agent, the salt removal rate of the film was 98.7%, which was 2.1% higher; the water recovery rate was 14.4%, and the pressure difference was 0.12 MPa, which was decreased by 0.08 MPa, according to Example 1. The method determines the cleaning qualification standard of waste reverse osmosis membrane, and compares the two parameters. It is found that the parameters of the waste reverse osmosis membrane after cleaning and repair have reached the cleaning qualification standard, and the old reverse osmosis membrane is basically close to the new membrane. performance.

Table No. 2.5 membrane cleaning reagents and parameters

Number of cleanings Cleaning and repairing salt rate Freshwater conductivity Water recovery rate Water permeability Pressure difference

Reagent 1% rate (μ (%) (MPa) Instruction manual

Example 3:

The No. 6 waste reverse osmosis membrane of model CPA3-8080 manufactured by Nitto Denko Co., Ltd. was subjected to the method and procedure of Example 1 to analyze the scale composition, confirming that the pollution type was silicate, carbonate and/or iron oxidation. Secondly, the membrane scale of different pollution types is analyzed and measured by three chemical analysis methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained. Finally, when the chemical analysis cannot be performed, the reverse osmosis membrane is tested by the SDI instrument. The color and density of the residue, the classification of the dirt, the brown residue is iron dirt; the white residue is silicon, sandy clay, calcium scale; the shape of the lens is inorganic colloid, calcium scale; from the form of odor and pollutants is sticky Judging thick, it also contains bio-fouling or organic dirt. Finally, the result of the analysis of the scale composition of the waste reverse osmosis membrane is that the main component of the membrane scale is Si0 ₂ , and also contains illite, mica and chlorite, mainly by Si, K, Ca, Mg, Fe, Al, C elements;

Demineralization rate = (Ei-Eo ) / Ei,

Water recovery rate ^0 / ¥1,

Pressure difference = Pi - Po,

Among them, the influent conductivity of the Ei-reverse osmosis membrane; the fresh water conductivity of the Eo-reverse osmosis membrane; the fresh water flow rate of the Vo-reverse osmosis membrane; the influent flow rate of the Vi_reverse osmosis membrane; the influent of the Pi_reverse osmosis membrane Inlet pressure; concentrated outlet pressure of the Po-reverse osmosis membrane.

The measurement conditions are as follows: The medium is tap water having a conductivity of 450-550 μs 1 cm, and the measurement pressure is 1. 5 MPa, and the measurement temperature is the tap water temperature, that is, normal temperature.

The various parameters measured are shown in Table 3. The initial salt removal rate of the film is 97.5 %, the water recovery rate is 12.0%, and the pressure difference is 0. 30 MPa; It can be seen from the initial desalination performance of the membrane that the membrane water recovery rate is low and the pressure difference is high. After the cleaning, the salt removal rate is 98.8 %, the water recovery rate is 18.6%, the increase is 6.6%, the pressure difference is 0. 19MPa, the drop is 0. llMPa, the waste method is determined according to the method of the embodiment 1. The immersion membrane cleaning qualification standard, comparing the two parameters found that the parameters of the waste reverse osmosis membrane after cleaning and repair have reached the cleaning qualification standard, the old reverse osmosis membrane is basically close to the performance of the new membrane. Instruction manual

Table 3. No. 6 membrane cleaning reagents and parameters

Example 4:

According to the method and procedure of Example 1 for the waste reverse osmosis membrane No. 267 of CPA3-8080 produced by Nitto Denko Co., Ltd., the scale composition analysis was carried out to confirm that the type of pollution was silicate and/or iron oxide; The membrane scales of different types of pollution are analyzed and determined by three chemical analysis methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained. Finally, when the chemical analysis cannot be performed, the residue on the reverse osmosis membrane is tested by the SDI instrument. Color, density, judge the classification of dirt, brown residue is iron dirt; white residue is silicon, sandy clay, calcium scale; crystal shape is inorganic colloid, calcium scale; finally obtained the results of membrane fouling analysis of waste reverse osmosis membrane The main component of the membrane scale is S i0 ₂ , and also contains illite, mica stone and oblique chlorite, which are mainly composed of Si, Ca, Mg, Fe and C elements;

Demineralization rate = ( Ei-Eo ) / Ei.

Water recycling

Pressure difference = Pi - Po,

The various parameters measured are shown in Table 4. The pressure difference is 0. 22 MPa. The initial water removal rate is 89. 9 %, the water recovery is 20.4%, and the pressure difference is 0.22 MPa. After Description

The cleaning rate of the waste reverse osmosis membrane is determined according to the method of Example 1. The salt removal rate is increased to 94. 4%, the increase is 4.5%, and the pressure difference is decreased to 0.16 MPa. Comparing the two parameters, it is found that the parameters of the waste reverse osmosis membrane after cleaning and repair have reached the cleaning qualification standard, and the old reverse osmosis membrane is basically close to the performance of the new membrane.

Table 4. No.267 membrane cleaning reagents and parameters

Example 5

The No. 47 waste reverse osmosis membrane of model CPA3-8080 produced by Nitto Denko Co., Ltd. was subjected to membrane scale component analysis according to the method and procedure of Example 1, and it was confirmed that the type of pollution was silicate and/or iron oxide; The membrane scales of different types of pollution are analyzed and determined by three chemical analysis methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained. Finally, when the chemical analysis cannot be performed, the residue on the reverse osmosis membrane is tested by the SDI instrument. Color, density, judging the classification of dirt, brown residue is iron dirt; judging from the odor and the shape of the contaminant, it also contains bio- or organic dirt, and finally the result of the analysis of the scale component of the waste reverse osmosis membrane is The main component of the scale is SiO ₂ , and also contains illite, mica and chlorite, mainly composed of Si, K, Ca, Mg, Fe, Al and C elements;

Demineralization rate = (Ei-Eo ) / Ei,

Water recovery rate ^0 / ¥1,

Pressure difference = Pi - Po,

The measurement conditions are as follows: The medium is a tap water having a conductivity of 450-550 μs / cm, and the measured pressure is 1. 5 MPa, and the measured temperature is the tap water temperature, that is, normal temperature. Instruction manual

The various parameters measured are shown in Table 5. The initial pressure difference of the membrane before cleaning was 1.26 MPa, and the membrane was blocked, and its initial desalination performance could not be determined. First, reverse rinsing is performed, and the flow path of the membrane is opened. Subsequently, it was cleaned using Formulation 1, and the pressure difference was gradually decreased to 0.16 MPa, and the salt removal rate and water recovery rate were 70.9% and 11.8%, respectively. After that, it is cleaned by formula three, mainly to remove organic matter, colloid, and SiO 2 on the surface of the film. After washing, the salt removal rate dropped to 69.4%, the water recovery rate rose to 19.7%, and the pressure difference dropped to 0.15 MPa. After repeated cleaning of Formulation 2 and Formulation 4, the repair agent was finally used for chemical repair to obtain a salt removal rate of 87.2%, a water recovery rate of 13.9%, and a pressure difference of 0.15 MPa, according to the method of Example 1. The cleaning qualification standard of waste reverse osmosis membrane was determined, and the parameters of the two were compared. It was found that the parameters of the waste reverse osmosis membrane after cleaning and repair reached the cleaning qualification standard, and the old reverse osmosis membrane basically approached the performance of the new membrane.

Table 5.47 membrane cleaning reagents and parameter changes

Example 6:

The No. 56 waste reverse osmosis membrane of model CPA3-8080 produced by Nitto Denko Co., Ltd. was analyzed according to the method and procedure of Experimental Example 1, and the contamination type was confirmed to be silicate and/or carbonate; The membrane scales of different types of pollution are analyzed and determined by three chemical analysis methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained. Finally, when the chemical analysis cannot be performed, the residue on the reverse osmosis membrane is tested by the SDI instrument. Color, density, judging the classification of dirt, judging from the odor and the shape of the contaminant, the fouling of the waste reverse osmosis membrane contains biofouling or organic dirt, and finally the membrane scale component analysis result of the waste reverse osmosis membrane is the membrane. The main component of scale is Si0 ₂ , which also contains organic matter, mainly composed of Si, K, Ca, Al and C elements;

(2) According to the results of the analysis of the scale component of the waste reverse osmosis membrane, the waste reverse osmosis membrane cleaning and repairing equipment shown in Fig. 8 of the specification is used, and the cleaning agent and the repairing agent of the present invention for different membrane scales are used, in the liquid High-speed cleaning at a flow rate of 10 m/s and repair at a pressure of 1.5 MPa;

Demineralization rate = (Ei-Eo) / Ei, Instruction manual

Water recycling

Pressure difference = Pi - Po,

The various parameters measured are shown in Table 6. The initial pressure difference of the membrane before washing was 1. 25 MPa, and the membrane was blocked, and the initial desalination performance could not be determined. First, reverse rinsing is performed, and the flow path of the membrane is opened. The sulphur removal rate and the water recovery rate were 72.9 % and 11.8%, respectively. After that, it is cleaned by formula 2, mainly to remove organic matter, colloid and SiO ₂ on the surface of the film. The singularity of the water pressure is reduced to 19.2%. After repeated cleaning of the formula 4 and the formula 5, the chemical repair is carried out by using the repairing agent, so that the salt removal rate is 87.2%, the water recovery rate is 14.6 %, and the pressure difference is ◦. 15MPa, according to the implementation. The method of Example 1 determines the cleaning qualification standard of the waste reverse osmosis membrane, and compares the two parameters. It is found that the parameters of the waste reverse osmosis membrane after cleaning and repair have reached the cleaning qualification standard, and the old reverse osmosis membrane is basically close to the new one. Membrane properties.

Table 6. No. 56 membrane cleaning reagent and parameter changes

Example 7

For the No. 38 waste reverse osmosis membrane of model CPA3-8080 produced by Nitto Denko Co., Ltd., according to the method and procedure of Experimental Example 1, the scale component analysis was carried out to confirm that the pollution type was silicate, carbonate and/or iron oxidation. Secondly, the membrane scale of different pollution types is analyzed and measured by three chemical analysis methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained. Finally, when the chemical analysis cannot be performed, the reverse osmosis membrane is tested by the SDI instrument. The color and density of the residue are judged by the classification of the dirt. The white residue is silicon, sandy clay, and calcium scale. The shape of the lens is inorganic colloid and calcium scale. The shape of the odor and the contaminant is viscous. Dirt or organic dirt, the result of the analysis of the scale composition of the waste reverse osmosis membrane is that the main component of the membrane scale is Si0 ₂ , and also contains illite, mica stone and oblique chlorite, mainly composed of Si,

K, Ca, M _g , Al, C elements; Instruction manual

(2) According to the results of the analysis of the scale component of the waste reverse osmosis membrane, the waste reverse osmosis membrane cleaning and repairing equipment shown in Fig. 8 of the specification is used, and the cleaning agent and the repairing agent of the present invention for different membrane scales are used, in the liquid High-speed cleaning at a flow rate of 10 m/s and repair at a pressure of 5 Mpa;

Demineralization rate = (Ei-Eo) /Ei,

Water recovery rate = \3⁄4/ 1,

Pressure difference = Pi - Po,

The various parameters measured are shown in Table 7. The initial pressure difference of the membrane before washing was 1.25 MPa, and the membrane was blocked, and its initial desalination performance could not be determined. First, reverse rinsing is performed, and the flow path of the membrane is opened. Subsequently, it was cleaned using Formulation 1, and the pressure difference was gradually decreased to 0.17 MPa, and the salt removal rate and water recovery rate were 2.1% and 11.8%, respectively. After that, it is cleaned by formula three, mainly to remove organic matter, colloid and SiO ₂ on the surface of the membrane. After washing, the salt removal rate decreased to 69.7%, the water recovery rate increased to 19.4%, and the pressure difference decreased to 0.15 MPa. After repeated cleaning of Formulation 4 and Formula 2, the repair agent was finally used for chemical repair to obtain a salt removal rate of 87.8%, a water recovery rate of 14.2%, and a pressure difference of 0.15 MPa, which was determined according to the method of Example 1. The cleaning qualification standard of waste reverse osmosis membrane was compared. It was found that the parameters of the waste reverse osmosis membrane after cleaning and repair reached the cleaning qualification standard, and the old reverse osmosis membrane basically approached the performance of the new membrane.

Table 7.38 Membrane cleaning reagents and parameter changes

Reagent 1% rate (μ (%) M ³ d- ¹ (MPa)

1 _Λ

Scm

Initial 1.25

1 Formulation 1 72.1 141.0 11.8 27.4 0.17

2 Formula 3 69.7 133.4 19.4 46.3 0.15

3 Formulation 4 64.2 162.4 18.9 44.2 0.14

4 Formula 2 57.6 182.2 22.6 54.8 0.13

6 Repair agent 87.8 54.0 14.2 33.3 0.15

Claims

Claim

1. A method for off-line cleaning and repairing off-line cleaning and repairing reagents for different waste reverse osmosis membranes, characterized in that it comprises the following steps: (1) Membrane scale of waste reverse osmosis membrane Ingredient analysis, the steps are as follows: Firstly, the sample of the retentate on the surface of the waste reverse osmosis membrane is collected, and the sample of the retentate is identified by chemical analysis, scanning electron microscopy and X-ray diffractometry, and the scale formed in the waste reverse osmosis membrane is characterized. Analysis, confirm that the pollution type is silicate, carbonate and/or iron oxide; secondly, the membrane scale of different pollution types is analyzed and determined by three chemical methods, and the composition of the membrane scale of the waste reverse osmosis membrane is obtained; Finally, when chemical analysis is not possible, the color and density of the residue on the reverse osmosis membrane are measured by the SDI meter to determine that the dirt is classified as: brown residue is iron scale; white residue is silicon, sandy clay, calcium scale; The shape of the lens is inorganic colloid, calcium scale; judging from the odor and the shape of the contaminant, it also contains biofouling or organic Scale; final waste obtained film reverse osmosis membrane fouling component analysis: the main component of membrane fouling Si0 _2, further comprising illite, mica and clinochlore stone, mainly by S i, K, Ca, Mg , Fe, Al Elemental composition; (2) According to the results of the analysis of the scale component of the waste reverse osmosis membrane, using the waste reverse osmosis membrane cleaning and repairing equipment, using the cleaning agent and the repairing agent in the liquid according to the application of the different membrane scales High-speed cleaning at a flow rate of 10 m/s, and repair under a pressure of 1.5 Mpa; (3) Continuous measurement of the relevant parameters of the membrane performance during chemical cleaning and chemical repair. The measurement conditions are: The medium is the conductivity. Tap water of 450-550 _ys Z cm, the measured pressure is 1. 5MPa, the measured temperature is the tap water temperature, that is, the normal temperature, and the cleaning is repaired to the qualified standard.

2 . The method for off-line cleaning and repairing of membrane fouling of different waste reverse osmosis membranes according to claim 1 , wherein the waste reverse osmosis membrane cleaning and repairing device is structurally constructed and connected as follows :

The device is mainly composed of a W door, a flow meter, a conductivity meter, a pressure gauge and a water inlet pH, a pressure pump P and a precision filter PP1 and PP2, and the wide door is made up of a filter vent valve V0, a tap water width VI, Tap water inlet valve V2, tap water outlet valve V3, acid detergent inlet valve V4, alkaline detergent inlet water V V5, repair agent inlet water V V6, total inlet valve, old membrane inlet valve V8, old membrane concentrated water Outlet valve V9, old membrane short-circuit valve V10, pure water-new membrane inlet valve VI I, old membrane fresh water outlet valve V12, new membrane inlet Shuigang V13, new membrane concentrated water outlet valve V14, new membrane short-circuit valve V15, Light 7 discharge valve V16, concentrated water discharge valve V17, repair agent concentrated water return valve V18, repair agent fresh water return valve V19, alkali washed concentrated water return valve V20, alkaline washed fresh water return valve V21, pickled fresh water return valve V22, acid The concentrated water return valve V23, the concentrated water check valve V24, V25, V26, V27 and the waste liquid discharge PS V28; the flow meter consists of the old membrane inlet flow meter Fl, the new membrane inlet flow meter F2, the old membrane Fresh water flow meter F3 and new membrane light flow meter F4; the conductance The instrument consists of an old membrane influent conductivity meter El, a new membrane influent conductivity meter E2 and an old membrane freshwater conductivity meter E3; the pressure gauge consists of a total inlet pressure gauge Pl, a new membrane inlet pressure gauge P2 and a new Membrane outlet pressure gauge P3;

The inlet of the precision filter PP1 is connected to the municipal water pipe through the tap water width VI, and the outlet is connected to the inlet of the water tank 1 through the tap water inlet valve V2, and the outlets of the tap water tank 1, the pickling tank 2, the caustic washing tank 3, and the repairing tank 4 respectively pass through the tap water. The outlet valve V3, the acidic detergent inlet valve V4, the alkaline detergent inlet valve V5, the repairing inlet valve V6 and the pressure pump 5 are connected to the water inlet, and the old membrane inlet conductivity meter El is connected in the middle, and the water inlet is connected. The pH of the instrument and the outlet of the pressure pump 5 are connected to the inlet of the waste reverse osmosis membrane 6 through the total inlet valve V7, the old membrane inlet water V8, the old membrane inlet flow meter F1, and the old membrane short-circuit valve V10, the new membrane. Water flow meter F2, new membrane inlet valve V13 is connected with the inlet of new membrane 7, medium inlet new membrane inlet pressure gauge P2, new membrane inlet conductivity meter E2, waste reverse osmosis membrane 6 concentrated water outlet through old membrane thick The water outlet valve V9, the new membrane inlet flow meter F2, the new membrane inlet valve V13 are connected to the inlet of the new membrane 7, the new membrane inlet pressure gauge P2, the new membrane inlet conductivity meter E2, and the new membrane Short circuit Claim

Valve V15 is connected to the inlet of PP2 precision filter. The waste reverse osmosis membrane fresh water outlet passes the old membrane fresh water outlet valve V12, the old membrane fresh water flowmeter F3, the repairing agent fresh water return valve V19, the alkali washed fresh water returning pottery V21, the pickled fresh water reflux 闽V22 is connected to the repair agent tank 4, the alkali washing tank 3, the pickling tank 2 inlet, the old membrane fresh water conductivity meter E3 is connected in series, the fresh water discharge 闽V16 is connected at the end, and the pure water-new membrane water inlet 闽 VI I is connected to the inlet of the new membrane 7, the new reverse osmosis membrane 7 concentrated water outlet is connected to the inlet of the precision filter PP2 through the new membrane concentrated water outlet Gang V14, the concentrated water check valve V24, and the new membrane outlet pressure gauge P3, new Reverse osmosis membrane 7 fresh water outlet through new membrane fresh water flow meter F4, repair agent fresh water side return valve V19, alkaline washed fresh water return valve V21, pickled fresh water reflux V22 and repair tank 4, alkali washing tank 3, pickling tank 2 The inlet is connected, the end is connected to the fresh water discharge valve V16, the PP2 precision filter outlet is passed through the repairing agent concentrated water return valve V18, the alkali washing concentrated water return valve V20, the pickling concentrated water return valve V23 and the repairing agent tank 4, the alkaline washing Box 3, pickling tank 2 inlet is connected, and the end is connected to the concentrated water discharge valve V17.

3 . The method for off-line cleaning and repairing of membrane fouls of different waste reverse osmosis membranes according to claim 1 , wherein the membrane performance related parameters include salt removal rate, water recovery rate, Pressure difference, calculated by the salt removal rate = (Ei-Eo) / Ei, water recovery = ₀ / Vi, differential pressure = Pi_Po, Ei- reverse osmosis membrane influent conductivity; Eo-reverse osmosis membrane freshwater conductance Rate; fresh water flow rate of Vo-reverse osmosis membrane; influent flow rate of Vi_reverse osmosis membrane; inlet inlet pressure of Pi_reverse osmosis membrane; concentrated water outlet pressure of Po-reverse osmosis membrane.

The above-mentioned eligibility standard is that the salt removal rate is 85.0% or more, 2MPa。 The water recovery rate of more than 12%, the pressure difference is less than 0. 2MPa.

5 . The method of claim 1 , wherein the method for determining the eligibility criteria is:

(1) In the cleaning and repairing process, in the tap water having a conductivity of 450-550 ys / cm, the measured pressure is 1. 5MPa, and the measured temperature is the tap water temperature, that is, the normal temperature condition, respectively, and the new reverse osmosis membrane and the waste anti-sediment are respectively determined. Various performance parameters of the permeable membrane;

(2) Comparing the measured parameters, the main differences are as follows: 1 The pressure difference is increased, the pressure difference of the new reverse osmosis membrane is 0. IMPa, and the initial pressure difference of the waste reverse osmosis membrane is much higher than 0. 2MPa _; 2 water recovery rate decreases, the water recovery rate of the new reverse osmosis membrane is 15%, and the water recovery rate of the waste reverse osmosis membrane is 10%; 3 the salt removal rate decreases, the new membrane salt removal rate is generally greater than 99%, and The demineralization rate of the reverse osmosis membrane on the 1st day decreased a lot, generally less than 80%;

(4) Comparing the performance of the cleaned reverse osmosis membrane with the new reverse osmosis membrane, and demarcating each parameter until the performance of the two is equivalent, the qualified standard for the cleaning and repair of the waste reverse osmosis membrane is established.

6 . The method for off-line cleaning and repairing of membrane fouls of different waste reverse osmosis membranes according to claim 1 , wherein the waste reverse osmosis membrane is first removed by Fe ³⁺ and A1 ^{3 . +} .

The off-line for cleaning of one of the 2-5 scale for different waste film reverse osmosis membrane as claimed in claim repair method, wherein said reverse osmosis membrane waste previously removed repair Fe ^{3 +} and A1 ³⁺ .