CN104016451B - The equipment and methods for using them of pressure field and the two film desalination of electric field synergistic effect - Google Patents

Abstract

The invention discloses a double-membrane desalination device and application method for the synergistic effect of a pressure field and an electric field. electric and pressure fields. In the equipment, the reverse osmosis membrane and the anion and cation membranes are arranged vertically to each other to form several reaction compartments. The water produced by the anion and cation membrane is directly discharged from the outlet pipe connected to the reaction compartment. Two adjacent reverse osmosis membranes are used as a group of reverse osmosis systems, and the interval between the membranes constitutes the water outlet corridor of the reverse osmosis system. The application of this equipment realizes the reverse osmosis process and the electrodialysis process at the same time, and the pressure field and the electric field interact with each other. The effect of the electrodialysis is enhanced through the action of the pressure field, the ion migration rate is accelerated, the salt removal rate is increased, and the energy consumption is reduced; through the action of the electric field Promote ion migration in wastewater, reduce solvent migration resistance in reverse osmosis process, improve water recovery rate, and improve the problem of reverse osmosis membrane fouling.

Description

Device and application method for double-membrane desalination under the synergistic effect of pressure field and electric field

technical field

The invention belongs to the technical field of environmental protection and energy saving, and relates to high-salt water desalination treatment equipment, in particular to a double-membrane desalination equipment and application method in which a pressure field and an electric field cooperate.

Background technique

Currently, with the rapid expansion of urbanization and industrialization, the economy is developing rapidly. The high salinity water discharged by major enterprises has caused great harm to the environment. The high salt in the water has caused changes in the living environment of aquatic organisms, deterioration of water quality and even death of organisms. In addition, with the increase of water demand and the shortage of fresh water resources, seawater or brackish water has to be desalinated at high cost and high investment to meet the needs of domestic and industrial water. Whether it is the desalination of high-salt water in wastewater or the desalination of seawater or brackish water, corresponding treatment processes or facilities are required to remove the salt in the water and meet the purpose of water demand.

At present, desalination technologies mainly include evaporation, electrodialysis, and reverse osmosis. Evaporation is mostly used for desalination of brine containing more than 10%, but high energy consumption is still the bottleneck; electrodialysis and reverse osmosis can be applied to desalination of brine containing medium and low concentrations (less than 5%). Electrodialysis desalination technology mainly involves two processes, one is the mobility of ions, and the other is the selective permeability of the membrane. Both processes are affected by the strength of the electric field, and the hydraulic state between the membranes is also one of the influencing factors. Electrodialysis desalination technology is prone to concentration polarization during operation, the water recovery rate is low, and the desalination efficiency also needs to be improved. The characteristic of reverse osmosis is that it can function under low operating pressure, and is less affected by factors such as pH value and temperature. The desalination efficiency can reach more than 98~99%. Problems such as high operation and maintenance costs.

Although the energy consumption of electrodialysis and reverse osmosis has been reduced compared with the past few years, there are still many problems. For the problem of desalination of high brine, there is still no perfect process and method.

Contents of the invention

The technical problem to be solved by the present invention is: when reverse osmosis or ion-selective membrane is used alone, only rely on a single pressure field or electric field, the recovery rate of water is low, energy consumption is high, membrane pollution is serious, and in practice The equipment is complicated.

The technical solution of the present invention is a double-membrane desalination device with the synergistic effect of a pressure field and an electric field.

chamber outlet pipe, concentrated water chamber outlet pipe, reverse osmosis outlet pipe, fresh water chamber, concentrated water chamber, reverse osmosis outlet corridor, shell

The water inlet buffer zone at the inner upper end, the reaction zone in the middle of the shell, and the reverse osmosis outlet water catchment area in the shell; the shell is in the shape of a cuboid, the upper end is closed, and there is a water inlet; the cathode and anode electrode plates are placed in the shell In the body, on both sides parallel to the wide sides of the cuboid, the permeate outlet corridor is the interval between two adjacent reverse osmosis membranes; the reaction zone in the middle of the shell is between two adjacent sets of reverse osmosis membranes. and the interval between the reverse osmosis membrane and the inner wall of the housing; in the reaction zone, the reverse osmosis membranes are placed at intervals parallel to the long sides of the cuboid of the housing; two adjacent reverse osmosis membranes form a group, and the anion membrane , The cationic membrane and the reverse osmosis membrane are vertically interlaced and embedded between two sets of reverse osmosis membranes and between the reverse osmosis membrane and the inner wall of the shell; multiple reaction chambers are composed of anion membranes, cationic membranes, reverse osmosis membranes and shells; Through the action of the electric field formed by the electrode plates with switchable cathode and anode polarity, the anion and cation move to the anode and the cathode respectively, so that the concentrated water chamber and the fresh water chamber are formed alternately in the equipment; the outlet pipe of the concentrated water chamber is arranged under the concentrated water chamber, and the outlet pipe of the fresh water chamber is arranged under the fresh water chamber The water outlet pipe of the fresh water chamber, the reverse osmosis water outlet corridor directly leads into the reverse osmosis outlet water catchment area, and the reverse osmosis outlet water pipe is arranged below the reverse osmosis outlet water catchment area.

The heights of the anion membrane and the cation membrane are the same as the height of the reaction zone, and the membrane width is equal to the distance between two adjacent sets of reverse osmosis membranes.

The water inlet buffer zone is located at the upper end of the shell, which is 1/10 of the shell volume, the reverse osmosis effluent catchment area is located at the lower end of the shell, which is 1/10 of the shell volume, and the reaction zone is located in the middle of the shell , is 2/5 of the shell volume.

The cathode and anode polarity switchable electrode plates are made of titanium ruthenium electrode plates, and multiple pairs of electrodes can be installed, and multiple sets of ion membrane modules can be installed between each pair of electrodes, and the number is determined according to the designed desalination rate and efficiency.

A method for applying the above-mentioned equipment is characterized in that the method is:

The high-pressure salt water is pumped into the above-mentioned equipment with a high pressure greater than the osmotic pressure of the reverse osmosis membrane, and at the same time, the electrode plates with switchable cathode and anode polarities are energized; In the reaction area, in each reaction cell, due to the effect of the electric field formed by the electrode plates with switchable cathode and anode polarity, cations migrate to the cathode through the cation membrane, and anions migrate to the anode through the anion membrane, so that the strong water chamber is staggered in the equipment and the fresh water chamber, the outlet water of the concentrated water chamber is collected and mixed with the raw water to enter the equipment through the outlet pipe of the concentrated water chamber, and the outlet water of the fresh water chamber is directly collected and utilized through the outlet pipe of the fresh water chamber. At the same time, due to the pressure field formed by the pump, the solvent is separated from the solution through The reverse osmosis membrane permeates into the reverse osmosis effluent corridor, and finally collects in the reverse osmosis effluent

The water catchment area is discharged from the reverse osmosis outlet pipe. After 2~8 hours of reaction, the polarity of the electrode plate with anode and cathode polarity can be changed to continue the reaction.

Beneficial effects of the present invention

1. In this invention, the reverse osmosis membrane and the anion and cation membrane are vertically arranged to form a reaction compartment, which realizes the reverse osmosis process and the electrodialysis process at the same time, and puts the whole reaction in the pressure field and electric field at the same time, improving the desalination effect of wastewater , which solves the problem of complex equipment in practice.

2. The invention enhances the effect of electrodialysis through the effect of pressure field, which can accelerate the ion migration rate, and after the reverse osmosis process separates the solvent, the concentration of the solution increases, which is more conducive to the migration of anions and cations during the electrodialysis process. Compared with single electrodialysis, under the same desalination effect, the invention requires short reaction time and low energy consumption.

3. The invention promotes the migration of ions in wastewater through the action of an electric field, and reduces the resistance of solvent migration in the reverse osmosis process. Compared with a single reverse osmosis process, it can increase the water recovery rate and reduce energy consumption. Moreover, due to the conversion of the electric field electrodes and ion migration transformation, each component of the wastewater has a moving force, thereby improving the problem of reverse osmosis membrane fouling.

Description of drawings

Fig. 1 is the schematic diagram of plane structure of equipment of the present invention;

Fig. 2 is a schematic diagram of the sectional structure along the 1-1 direction of Fig. 1;

FIG. 3 is a schematic diagram of the sectional structure along the 2-2 direction in FIG. 1 .

Detailed ways

Example 1

As shown in Figure 1-3, a double-membrane desalination device with a pressure field and an electric field synergistically includes a housing 1, a reverse osmosis membrane 2, an anion membrane 3, a cation membrane 4, and an electrode plate with switchable polarity. 5. Fresh water chamber outlet pipe 6, concentrated water chamber outlet pipe 7, reverse osmosis outlet pipe 8, fresh water chamber 9, concentrated water chamber 10, reverse osmosis outlet corridor 11, water inlet buffer zone 12 at the upper end of the shell, middle part of the shell The reaction zone 13 in the shell and the reverse osmosis outlet water catchment area 14 in the shell, the shell 1; the shell is in the shape of a cuboid, the upper end is closed, and a water inlet is left; the negative and positive electrode plates 5 are placed in the shell and parallel to On both sides of the broadside of the cuboid, the permeate outlet corridor 11 is the interval between two adjacent reverse osmosis membranes; the reaction zone 13 in the middle of the housing is between the adjacent two groups of reverse osmosis membranes and The interval between the reverse osmosis membrane and the inner wall of the housing; in the reaction zone 13, in parallel

Reverse osmosis membranes 2 are placed at intervals on the long sides of the cuboid of the housing; two adjacent reverse osmosis membranes form a group, and the anion membrane 3, cation membrane 4 and the reverse osmosis membrane are vertically interlaced and embedded between the two groups of reverse osmosis membranes And between the reverse osmosis membrane and the inner wall of the shell; multiple reverse osmosis membranes, cationic membranes, reverse osmosis membranes and shells are formed

Response chamber: through the action of the electric field formed by the electrode plate 5 with switchable cathode and anode polarity, the anion and cation move to the anode and cathode respectively, so that the concentrated water chamber 10 and the fresh water chamber 9 are formed alternately in the equipment; concentrated water is set under the concentrated water chamber 10 Room outlet pipe 7, fresh water room outlet pipe 6 is set below the fresh water room 9, the reverse osmosis water outlet corridor 11 directly leads into the reverse osmosis outlet water catchment area 14, and the reverse osmosis outlet water outlet pipe 8 is arranged below the reverse osmosis outlet water catchment area 14.

The water inlet buffer zone 12 is located at the upper end of the shell, which is 1/10 of the shell volume, and the reverse osmosis outlet water catchment area 14 is located at the lower end of the shell, which is 1/10 of the shell volume. The middle part of the shell is 2/5 of the volume of the shell.

In this embodiment, the housing has a length of 260 mm, a width of 190 mm, and a height of 260 mm, which dimensions can be changed according to actual needs. The volume ratio of the influent buffer zone 12, the reaction zone 13, and the reverse osmosis effluent catchment zone 14 is 1:4:1.

The reverse osmosis membrane 2 adopts a reverse osmosis membrane with a maximum withstand pressure of 70 bar, with a length of 260 mm and a height of 270 mm. The top of the reverse osmosis membrane 2 is connected to the top of the reaction zone 13, the lower end of the reverse osmosis membrane 2 extends into the reverse osmosis effluent catchment area by 10mm, and the left and right ends of the reverse osmosis membrane 2 are closely connected with the casing. The distance between two adjacent membranes is 10mm, the adjacent reverse osmosis membranes form a group, the distance between two adjacent groups of membranes is 40mm, the distance between the reverse osmosis membrane 2 and the two sides of the shell 1 is also 40mm, and the shell is placed 3 sets (6 sheets) of reverse osmosis membranes 2. Perpendicular to the reverse osmosis membrane 2, the anion and cation membranes are embedded between the two sets of reverse osmosis membranes and between the reverse osmosis membrane and the shell, that is, the length of the membrane is 40mm, the height is 260mm, and the distance between the anion membrane 3 and the cation membrane 4 is 40mm, and they are staggered. A total of 12 anion membranes 3 and 12 cationic membranes 4 are placed, and 20 reaction compartments are formed with the reverse osmosis membrane 2 and the housing 1. Each row of four reaction compartments constitutes a group of fresh water chambers 9 or concentrated water chambers 10, five rows in total, three rows of fresh water chambers and two rows of concentrated water chambers. Each reaction compartment of the chamber is connected. The concentrated water chamber outlet pipe 7 is arranged under the concentrated water chamber, and the branch pipe of the water outlet pipe is connected with each reaction compartment of the concentrated water chamber. A reverse osmosis outlet pipe 8 is arranged below the reverse osmosis outlet water catchment area 14 . The cathode and anode polarity switchable electrode plate 5 adopts titanium ruthenium electrode plate.

A method of applying the above-mentioned equipment is that the high-pressure brine is pumped into the above-mentioned equipment with a high pressure greater than the osmotic pressure of the reverse osmosis membrane, and at the same time, the electrode plate 5 with anode and cathode polarity can be switched; Each reaction compartment flows into the reaction zone 13 from top to bottom, and in each reaction compartment, due to

Electrode plates 5 with switchable cathode and anode properties form an electric field, cations migrate to the cathode through the cation membrane 4, and anions migrate to the anode through the anion membrane 3, so that concentrated water chambers 10 and fresh water chambers 9 are formed alternately in the equipment. Concentrated water The outlet water from chamber 10 passes through the outlet pipe 7 of the concentrated water chamber and is mixed with the raw water to enter the equipment, and the fresh water chamber 9 exits

The water is directly collected and utilized through the outlet pipe 6 of the fresh water chamber, and at the same time, due to the pressure field formed by the pump, the solvent is separated from the solution and permeates through the reverse osmosis membrane 2 to the reverse osmosis outlet corridor 11, and finally gathers in the reverse osmosis outlet water catchment area 14 , discharged from the reverse osmosis outlet pipe 8, after 2-8 hours of reaction, change the polarity of the cathode and anode polarity-switchable electrode plates 5, and continue the reaction.

In order to improve the desalination efficiency, the reverse osmosis membrane 2, the anion membrane 3 and the cation membrane 4 constitute the reaction cell, so that the reverse osmosis process and the electrodialysis process are carried out at the same time, and because the whole reaction is in the pressure field and the electric field at the same time, through the pressure field The effect can enhance the effect of electrodialysis, accelerate the ion migration rate, and after the reverse osmosis process separates the solvent, the concentration of the solution increases, which is more conducive to the migration of anions and cations during the electrodialysis process. Therefore, during the operation of the equipment, it can be compared with a single electrodialysis equipment. Shorten power-on time.

The electric field action of the equipment promotes the migration of ions in the wastewater, reduces the solvent migration resistance in the reverse osmosis process, and reduces the operating pressure compared with a single reverse osmosis process. And because of the conversion effect of the electric field electrode, the ion migration transformation makes each component of the wastewater have a moving force, which improves the problem of reverse osmosis membrane pollution, so the number of backwashing of the membrane of the equipment can be reduced.

Application Example 1

A double-membrane desalination device with the synergistic effect of pressure field and electric field in Example 1 was applied to treat high-salt water produced by various chemical enterprises in a certain coal chemical industry park. It is carried out at room temperature, the pH of the raw water is 8~9, and the salt content is 3500mg/L. The equipment operates with an inlet water pressure of 15bar, a current density of 10~20mA/cm ² , a residence time of 10min in the reaction chamber, a concentrated water concentration of 14000~15000mg/L in the outlet water, and a desalination rate of the freshwater system of 30%~40%. The recovery rate of the permeation system is 90%, and the desalination rate reaches 98%. The equipment is not energized, and the treatment is carried out under a single pressure field. The reaction time is the same. The recovery rate of the reverse osmosis system is 79%, and the desalination rate reaches 96%. After one month of use, the surface of the reverse osmosis membrane is observed with an electronic scanning microscope. The membrane fouling layer is thinner than that of single reverse osmosis; the equipment is not pressurized, and the treatment is performed under a single electric field. The reaction time is the same, the concentrated water concentration of the effluent is 7000~8000mg/L, and the desalination rate of the fresh water system is about 20%. It can be seen from the comparison that the effect of the pressure field enhances the electrodialysis effect and accelerates the ion migration rate. Compared with the single electrodialysis, under the same desalination effect, the invention requires a shorter reaction time and lower energy consumption. At the same time, the action of the electric field promotes the ionization of wastewater

Sub-migration reduces the solvent migration resistance in the reverse osmosis process. Compared with a single reverse osmosis process, it improves the water recovery rate and reduces energy consumption. Moreover, due to the conversion effect of the electric field electrode and ion migration transformation, each component of the wastewater has a moving force, which improves the problem of reverse osmosis membrane pollution.

Claims (6)

1. A double-membrane desalination device with synergistic effect of pressure field and electric field, characterized in that the device includes a shell (1), reverse osmosis membrane (2), anion membrane (3), cation membrane (4), cathode and anode Electrode plate for sex conversion (5), fresh water chamber outlet pipe (6), concentrated water chamber outlet pipe (7), reverse osmosis outlet pipe (8), fresh water chamber (9), concentrated water chamber (10), reverse osmosis outlet water The corridor (11), the water inlet buffer zone (12) at the upper end of the shell, the reaction zone (13) in the middle of the shell, and the reverse osmosis effluent catchment area (14) in the shell; the shell is in the shape of a cuboid, and the upper end Closed, leaving a water inlet; the cathode and anode polarity conversion electrode plates (5) are placed in the casing on both sides parallel to the broad side of the cuboid, and the reverse osmosis water outlet corridor (11) is the adjacent two reverse The space between the osmotic membranes; the reaction zone (13) in the middle of the shell is the space between the adjacent two sets of reverse osmosis membranes and the space between the reverse osmosis membrane and the inner wall of the shell; the shell In the reaction zone (13) in the middle of the body, reverse osmosis membranes (2) are placed at intervals parallel to the long sides of the cuboid of the shell; two adjacent reverse osmosis membranes form a group, and the anion membrane (3), cation membrane ( 4) Parallel to the electrode plate (5) for negative and negative polarity conversion, vertically interlaced with the reverse osmosis membrane and embedded between two sets of reverse osmosis membranes and between the reverse osmosis membrane and the inner wall of the shell; anion membrane, cation membrane, reverse osmosis membrane The permeable membrane and the shell constitute a plurality of reaction compartments; through the action of the electric field formed by the electrode plate (5) for the polarity conversion of the cathode and the cathode, the anion and the cation move to the anode and the cathode respectively, so that the concentrated water chamber (10) and the fresh water chamber (10) are staggered in the equipment. room (9); the concentrated water room outlet pipe (7) is set under the concentrated water room (10), the fresh water room outlet pipe (6) is set under the fresh water room (9), and the reverse osmosis water outlet corridor (11) directly leads to A reverse osmosis outlet water catchment area (14), and a reverse osmosis outlet water pipe (8) is arranged below the reverse osmosis outlet water catchment area (14). 2. The double-membrane desalination equipment under the synergistic effect of pressure field and electric field according to claim 1, characterized in that the reverse osmosis membrane (2) is made into a rectangular shape, and the width of the reverse osmosis membrane (2) is equal to the length of the casing , closely connected with the shell, the upper end of the reverse osmosis membrane (2) reaches the top of the reaction zone (13) in the middle of the shell, and the lower end of the reverse osmosis membrane enters the reverse osmosis effluent catchment area (14), and the reverse osmosis effluent gallery The channel (11) directly leads to the reverse osmosis effluent catchment area (14). 3. The device for double-membrane desalination under the synergistic effect of pressure field and electric field according to claim 1, characterized in that the height of the anion membrane (3) and the cation membrane (4) is in relation to the reaction zone (13) in the middle of the shell The height is the same, and the membrane width is equal to the distance between two adjacent sets of reverse osmosis membranes. 4. The device for double-membrane desalination under the synergistic effect of pressure field and electric field according to claim 1, characterized in that, the water inlet buffer zone (12) is located at the upper end of the housing, which is 1/10 of the volume of the housing, and the reverse osmosis water The water collection area (14) is located at the lower end of the shell, which is 1/10 of the volume of the shell, and the reaction zone (13) in the middle of the shell is located in the middle of the shell, which is 2/5 of the volume of the shell. 5 . The double-membrane desalination device under the synergistic effect of pressure field and electric field according to claim 1 , characterized in that the electrode plate ( 5 ) for cathode-to-anode polarity conversion is a titanium-ruthenium electrode plate. 6. A method of applying the device according to claim 1, characterized in that, the method is: The high brine is pumped into the device described in claim 1 with a high pressure greater than the osmotic pressure of the reverse osmosis membrane, and at the same time, the electrode plate (5) for positive and negative conversion is energized; the high brine is evenly distributed to the Each reaction cell flows into the reaction zone (13) in the middle of the shell from top to bottom. In each reaction cell, due to the electric field formed by the electrode plate (5) for positive and negative polarity conversion, cations pass through the cation membrane (4 ) migrates to the cathode, and the anions migrate to the anode through the anion membrane (3), so that the concentrated water chamber (10) and the fresh water chamber (9) are staggered in the equipment, and the water from the concentrated water chamber (10) passes through the concentrated water chamber outlet pipe (7 ) and the raw water are mixed and circulated into the equipment, and the outlet water from the fresh water chamber (9) is directly collected and utilized through the outlet pipe (6) of the fresh water chamber. The reverse osmosis effluent corridor (11) permeates, and finally collects in the reverse osmosis effluent catchment area (14), and is discharged from the reverse osmosis outlet pipe (8). After reacting for 2 to 8 hours, the electrode plate (5) for negative and negative polarity conversion is changed. Sex, continue to react.