Industrial wastewater thermal gradient temperature control type membrane distillation treatment device and process

Abstract

The invention discloses a thermal gradient temperature control type membrane distillation treatment device for industrial wastewater, relates to the technical field of wastewater treatment, and aims to solve the problems that the fluid resistance of a local area is increased in the membrane distillation process, and the separation and purification effect is poor as the temperature difference between the two sides of a membrane is smaller than the fluid temperature difference. The membrane distillation device specifically comprises a membrane shell and water distribution assemblies arranged in the membrane shell and is mainly applied to the membrane distillation treatment process of industrial wastewater, the water distribution assemblies are synchronously arranged on the water inlet side and the water outlet side of the wastewater, the flow direction of the wastewater is changed through tangential grooves and vertical grooves in the water distribution assemblies, and the fluid resistance of a local area in a concentration boundary layer is weakened; and secondary flow guide mixed hot working media and wastewater are adopted to jointly complete cyclic distillation, and based on reduction of membrane interface local area fluid resistance and damage of membrane interface temperature and concentration polarization phenomena, the driving force of the membrane distillation process is increased, and the separation and purification effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas purification, and in particular to a thermal gradient temperature-controlled membrane distillation treatment device and process for industrial wastewater. Background Art

[0002] The papermaking industry, leather manufacturing industry, food production and processing industry, etc. all generate a large amount of organic wastewater. In addition, the leachate generated during the recycling and treatment of domestic waste is also an organic wastewater with a high concentration of organic matter. Organic wastewater often contains rich carbohydrates, proteins, oils, lignin and other organic matter, which exist in a suspended or dissolved state. It can be decomposed by the biochemical action of microorganisms, or it can be adsorbed by activated carbon, macroporous resin, diatomaceous earth and other methods. In addition to these methods, membrane separation technology can also be used to effectively treat wastewater.

[0003] A background introduction to membrane separation technology is given. The principle of membrane separation wastewater treatment is that the two sides of the membrane distillation system are separated from each other by a hydrophobic porous membrane, and there is a temperature difference between the water temperatures on both sides of the membrane surface. Due to the temperature gradient between the inlet side and the outlet side, a vapor pressure difference is generated on both sides of the hydrophobic porous membrane. This pressure difference forces the water vapor on the inlet side to diffuse into the other side through the membrane pores on the membrane surface. After the water vapor passes through the membrane surface, it condenses into liquid on the outlet side, while the non-volatile components in the inlet solution are retained on the inlet side of the hydrophobic membrane, thereby realizing the separation and purification of the solution and the non-volatile solutes.

[0004] Referring to the Chinese patent publication number CN111675411A, solar energy heating is used for energy supply and membrane pollution is avoided. However, when it is applied to wastewater treatment, heat distribution is provided by evenly distributed heat collecting pipes. The concentration boundary layer in the membrane distillation process increases the fluid resistance in the local area, and the temperature boundary layer makes the temperature difference on both sides of the membrane smaller than the temperature difference of the fluid body, which reduces the driving force of the membrane distillation process, resulting in poor separation and purification. For this reason, this application proposes a solution. Summary of the Invention

[0005] The purpose of the present invention is to provide an industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device to solve the problem of increased fluid resistance in local areas during membrane distillation and poor separation and purification effect caused by the temperature difference between the two sides of the membrane being smaller than the fluid temperature difference.

[0006] The object of the present invention can be achieved by the following technical solution: an industrial wastewater thermal gradient temperature control membrane distillation treatment device, comprising a membrane shell, an inner membrane layer is centrally arranged in the membrane shell, and a water separation component is sheathed on the outer side of the membrane shell corresponding to the inner membrane layer; The water diversion assembly includes an upper water diversion plate and a lower water diversion plate, the upper water diversion plate and the lower water diversion plate are spaced apart and sleeved outside the inner membrane layer, the outer circumference of the upper water diversion plate is provided with a tangential groove, and the outer circumference of the lower water diversion plate is provided with a vertical groove; The tangential grooves and vertical grooves are staggered in the vertical direction, and the upper water distribution plate and the lower water distribution plate are close to the inner membrane layer and the parts corresponding to each tangential groove and vertical groove are through-opening structures. A through-hole tube is provided in the middle of the inner membrane layer, and a through-hole tube is provided on the through-hole tube which is connected to the water distribution component.

[0007] It is further configured as follows: water inlet pipes and water outlet pipes are symmetrically arranged on both sides of the membrane shell, and each group of the water inlet pipes and water outlet pipes corresponds to the upper water distribution plate and the lower water distribution plate respectively.

[0008] It is further configured as follows: an outer membrane is attached to the inner wall of the membrane shell, and the outer membrane is connected to the water inlet pipe and the water outlet pipe.

[0009] It is further configured as follows: four evenly distributed guide ring rods are arranged at intervals on the outside of the inner membrane layer, the upper water distribution plate and the lower water distribution plate, and partitions connected to the outer membrane are installed on the outside of two of the guide ring rods.

[0010] It is further configured as follows: the partition separates the cavity formed by the membrane shell, the upper water distribution plate and the lower water distribution plate into a hot water cavity and a cold water cavity from the water inlet pipe to the water outlet pipe.

[0011] It is further configured as follows: the cross section of the guide ring rod is semicircular, and the middle parts of the other two guide ring rods are provided with gap holes, and each of the gap holes corresponds to the water inlet pipe and the water outlet pipe in the horizontal direction.

[0012] It is further configured as follows: a locking top plug and a lower sealing plug are respectively installed at the upper and lower ends of the membrane shell, the locking top plug and the lower sealing plug are used to lock the vertical position of the inner membrane layer, and an A inlet and a B outlet are respectively opened on the locking top plug and the lower sealing plug.

[0013] It is further configured as follows: packaging seats are installed at the upper and lower ends of the outer side of the inner film layer, and the packaging seats are used to fix the upper water distribution plate and the lower water distribution plate.

[0014] The present invention also proposes a thermal gradient temperature-controlled membrane distillation process for treating industrial wastewater, comprising the following steps: Step 1: The hot working medium discharged from the constant temperature water bath enters the through-hole tube through inlet A to provide membrane heat. The wastewater enters the membrane shell from the water inlet pipe, is first filtered by the external membrane and then fills the heat capacity cavity. Step 2: The wastewater passes through the membrane shell in a vertical direction and enters the heat capacity chamber. It is guided by the tangential grooves and vertical grooves set on the upper and lower water separation plates respectively, and the rotating inflow is adjusted from the direction perpendicular to the membrane surface to the tangential direction of the membrane surface to form a vortex flow; Step 3: After passing through the upper and lower water separation plates, the wastewater enters the inner membrane layer of the heat capacity chamber to complete membrane distillation, and is finally discharged from the outlet pipe to complete the purification treatment. The remaining wastewater and hot working medium mixture is discharged from the B outlet through the through-hole pipe and returned to the constant temperature water bath for the circulation supply of hot working medium.

[0015] The present invention has the following beneficial effects: Water separation components are set simultaneously on the inlet and outlet sides of the wastewater. The tangential grooves and vertical grooves in the water separation components change the flow direction of the wastewater, weaken the fluid resistance in the local area of ​​the concentration boundary layer, and use secondary diversion to mix the hot working medium and the wastewater to complete the circulating distillation. Based on reducing the fluid resistance in the local area of ​​the membrane interface, the temperature and concentration polarization phenomenon of the membrane interface is destroyed, the driving force of the membrane distillation process is increased, and the separation and purification effect is improved.

[0016] The setting of the external membrane is to carry out double filtration before and after the wastewater membrane distillation treatment. The wastewater entering and exiting the filtration is composed of an inlet pipe and an outlet pipe, which can effectively improve the service life of the inner membrane layer. The setting positions of the inlet pipe and the outlet pipe correspond to the upper water distribution plate and the lower water distribution plate respectively. The purpose is to make the wastewater entering from adjacent inlet pipes form intersecting fluid flow directions, fundamentally changing the fluid resistance in the local area of ​​the inner membrane layer interface, and the wastewater entering the heat capacity cavity through the inlet pipe can also be guided and diverted under the setting of the semicircular guide ring rod, thereby reducing the fluid resistance in the inner membrane layer area caused by direct impact of the wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic cross-sectional view of the internal structure of the present invention; Figure 3 This is a diagram of the installation structure of the water distribution component of the present invention; Figure 4 A top cross-sectional view of the upper water diversion plate in the water diversion assembly of the present invention; Figure 5 A top sectional view of the lower water distribution plate in the water distribution assembly of the present invention; Figure 6 It is a front cross-sectional view of the present invention; Figure 7 It is a side sectional view of the present invention.

[0019] In the figure: 1. membrane shell; 2. water inlet pipe; 3. water outlet pipe; 4. packaging seat; 5. upper water distribution plate; 6. lower water distribution plate; 7. tangential groove; 8. vertical groove; 9. inner membrane layer; 10. partition; 11. through-hole tube; 12. guide ring rod; 13. gap hole; 14. perforation; 15. external membrane; 16. locking top plug; 17. lower sealing plug. DETAILED DESCRIPTION

[0020] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1: To address the problem of increased fluid resistance in local areas during membrane distillation and poor separation and purification effects caused by the temperature difference between the two sides of the membrane being smaller than the fluid temperature difference, the following technical solution is proposed: Reference Figure 1 - Figure 7 As shown, the industrial wastewater thermal gradient temperature control membrane distillation treatment device in this embodiment includes a membrane shell 1, an inner membrane layer 9 is centrally arranged in the membrane shell 1, and a water separation component is provided on the outside of the membrane shell 1 corresponding to the inner membrane layer 9. The water separation component includes an upper water separation plate 5 and a lower water separation plate 6. The upper water separation plate 5 and the lower water separation plate 6 are spaced apart and sleeved outside the inner membrane layer 9. A tangential groove 7 is opened through the outer peripheral side of the upper water separation plate 5, and a vertical groove 8 is opened through the outer peripheral side of the lower water separation plate 6; The tangential grooves 7 and the vertical grooves 8 are staggered in the vertical direction. The upper water separation plate 5 and the lower water separation plate 6 are close to the inner membrane layer 9 and the parts corresponding to each tangential groove 7 and vertical groove 8 are all through-port structures. After the wastewater enters the membrane shell 1, the flow direction of the wastewater is changed by the water separation component, so that the wastewater produces a vortex flow effect, destroying the temperature and concentration polarization phenomenon at the boundary of the inner membrane layer 9, and enhancing the shear force and shear velocity at the membrane boundary, thereby improving the membrane flux; The fluid flow process before the water separation component performs wastewater membrane distillation is described: the wastewater passes through the membrane shell 1 in a vertical direction and enters the heat capacity chamber. It is guided by the tangential grooves 7 on the upper water separation plate 5 to adjust the vertical direction to tangential contact, and is also guided by the vertical grooves 8 on the lower water separation plate 6 to adjust the vertical direction to deflected contact. The combination of the two forms a rotating inflow that adjusts the wastewater from a direction perpendicular to the membrane surface to a tangential direction along the membrane surface, forming a vortex flow. Reference Figure 2 and Figure 3As shown, the upper water separation tray 5 and the lower water separation tray 6 are spaced apart, with three of each. A through-hole tube 11 is provided in the middle of the inner membrane layer 9. The through-hole tube 11 is provided with a perforation 14 connected to the water separation assembly. The through-hole tube 11 forms a flow channel for the hot working medium, and the membrane distillation heat exchange between the wastewater and the hot working medium is carried out through the perforation 14. After the membrane distillation is completed, the purified water is discharged as steam through the inner membrane layer 9, and the unpurified wastewater is discharged together with the hot working medium to continue the next cycle of distillation process. Reference Figure 2 and Figure 6 As shown, the membrane shell 1 is symmetrically provided with an inlet pipe 2 and an outlet pipe 3 on both sides, and each set of the inlet pipe 2 and the outlet pipe 3 corresponds to the upper water distribution plate 5 and the lower water distribution plate 6 respectively. The inner wall of the membrane shell 1 is attached with an external membrane 15, which is connected to the inlet pipe 2 and the outlet pipe 3; Among them, the setting of the external membrane 15 is to perform double filtration before and after the wastewater membrane distillation treatment. The wastewater entering and leaving the filtration is composed of the water inlet pipe 2 and the water outlet pipe 3, which effectively improves the service life of the inner membrane layer 9. The purpose of setting the positions of the water inlet pipe 2 and the water outlet pipe 3 to correspond to the upper water distribution plate 5 and the lower water distribution plate 6 respectively is to enable the wastewater entering the adjacent water inlet pipes 2 to form an intersecting fluid flow direction, fundamentally changing the fluid resistance in the local area of ​​the interface of the inner membrane layer 9; Reference Figure 6 and Figure 7 As shown, four evenly distributed guide ring rods 12 are arranged at intervals on the outside of the inner membrane layer 9, the upper water distribution plate 5 and the lower water distribution plate 6, among which the outer sides of two guide ring rods 12 are installed with partitions 10 connected to the outer membrane 15. The partitions 10 separate the cavity formed by the membrane shell 1, the upper water distribution plate 5 and the lower water distribution plate 6 from the water inlet pipe 2 to the water outlet pipe 3 into a hot water chamber and a cold water chamber.

[0022] The basic principle of the present invention is as follows: in the membrane distillation process for treating industrial wastewater, water separation components are synchronously arranged on the inlet and outlet sides of the wastewater. The tangential grooves and vertical grooves in the water separation components change the flow direction of the wastewater, weakening the fluid resistance in the local area of ​​the concentration boundary layer. Secondary diversion is used to mix the hot working medium and the wastewater to complete the circulating distillation together, thereby increasing the driving force of the membrane distillation process and improving the separation and purification effect.

[0023] Example 2: This example is based on Example 1. After the wastewater is directed into the heat chamber and before it contacts the inner membrane layer 9, how to redirect the wastewater can effectively reduce the fluid resistance in the local area. The following technical solutions are proposed. Reference Figure 1 - Figure 7As shown, the cross-section of the guide ring rod 12 is semicircular, and the middle part of the other two guide ring rods 12 is provided with a gap 13. Each gap 13 corresponds to the water inlet pipe 2 and the water outlet pipe 3 in the horizontal direction. The wastewater entering the heat capacity chamber through the water inlet pipe 2 can also be guided and diverted under the setting of the semicircular guide ring rod 12, thereby reducing the fluid resistance in the inner membrane layer 9 area caused by direct impact of the wastewater. The upper and lower ends of the membrane shell 1 are respectively installed with a locking top plug 16 and a lower sealing plug 17, which are used to lock the vertical position of the inner membrane layer 9. The locking top plug 16 and the lower sealing plug 17 are respectively provided with an A inlet and a B outlet. The hot working medium is input through the A inlet and then flows out through the B outlet. The input and outflow of the hot working medium are both carried out by a constant temperature water bath, forming a circulating supply. Packaging seats 4 are installed at the upper and lower ends of the outer side of the inner membrane layer 9. The packaging seats 4 are used to fix the upper water separation plate 5 and the lower water separation plate 6. The setting of the packaging seat 4 can effectively fix the inner membrane layer 9, the upper water separation plate 5 and the lower water separation plate 6 in the membrane shell 1, and prevent the inner membrane layer 9 from being deformed and wrinkled due to the longitudinal impact of wastewater, which affects the normal membrane distillation process.

[0024] Example 3: Reference Figure 1 - Figure 7 As shown, the present invention also proposes a thermal gradient temperature-controlled membrane distillation process for treating industrial wastewater, comprising the following steps: Step 1: The hot working medium discharged from the constant temperature water bath enters the through-hole pipe 11 through the A inlet to provide membrane heat. The wastewater enters the membrane shell 1 from the water inlet pipe 2, is first filtered by the external membrane 15 and then fills the heat capacity chamber; Step 2: The wastewater passes through the membrane shell 1 in a vertical direction and enters the heat capacity chamber. It is guided by the tangential grooves 7 and vertical grooves 8 respectively set on the upper water separation plate 5 and the lower water separation plate 6, and the rotating inflow is adjusted from the direction perpendicular to the membrane surface to the tangential direction of the membrane surface to form a vortex flow; Step 3: After passing through the upper water separation plate 5 and the lower water separation plate 6, the wastewater enters the inner membrane layer 9 of the heat capacity chamber to complete membrane distillation, and is finally discharged from the outlet pipe 3 to complete the purification treatment. The remaining wastewater and hot working medium mixture is discharged from the B outlet through the through-hole pipe 11 and returned to the constant temperature water bath for the circulation supply of hot working medium.

[0025] In summary: This is a membrane distillation treatment process applied to industrial wastewater. Water separation components are simultaneously set on the inlet and outlet sides of the wastewater. The tangential grooves and vertical grooves in the water separation components change the flow direction of the wastewater, weakening the fluid resistance in the local area of ​​the concentration boundary layer. Secondary diversion is used to mix the hot working medium and the wastewater to complete the circulating distillation. It is based on reducing the fluid resistance in the local area of ​​the membrane interface, destroying the temperature and concentration polarization phenomenon of the membrane interface, and increasing the driving force of the membrane distillation process, thereby improving the separation and purification effect.

[0026] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

Claims

1. An industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device, comprising a membrane shell (1), characterized in that: An inner membrane layer (9) is centrally arranged in the membrane shell (1), and a water separation component is provided on the outside of the membrane shell (1) corresponding to the inner membrane layer (9); The water distribution assembly comprises an upper water distribution plate (5) and a lower water distribution plate (6), wherein the upper water distribution plate (5) and the lower water distribution plate (6) are spaced apart and sleeved outside the inner membrane layer (9); a tangential groove (7) is provided through the outer circumference of the upper water distribution plate (5), and a vertical groove (8) is provided through the outer circumference of the lower water distribution plate (6); The tangential grooves (7) and the vertical grooves (8) are arranged in a staggered manner in the vertical direction; the upper water separation plate (5) and the lower water separation plate (6) close to the inner membrane layer (9) and corresponding to each tangential groove (7) and vertical groove (8) are all through-opening structures; a through-hole tube (11) is provided in the middle of the inner membrane layer (9), and a through-hole tube (11) is provided with a through-hole (14) connected to the water separation component.

2. The industrial wastewater thermal gradient temperature controlled membrane distillation treatment device according to claim 1, characterized in that: Water inlet pipes (2) and water outlet pipes (3) are symmetrically arranged on both sides of the membrane shell (1), and each set of the water inlet pipes (2) and water outlet pipes (3) corresponds to the upper water distribution plate (5) and the lower water distribution plate (6), respectively.

3. The industrial wastewater thermal gradient temperature controlled membrane distillation treatment device according to claim 2, characterized in that: An external membrane (15) is attached to the inner wall of the membrane shell (1), and the external membrane (15) is connected to the water inlet pipe (2) and the water outlet pipe (3).

4. The industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device according to claim 3, characterized in that: Four evenly distributed guide ring rods (12) are arranged at intervals on the outside of the inner membrane layer (9), the upper water distribution plate (5) and the lower water distribution plate (6), wherein the outsides of two of the guide ring rods (12) are equipped with partitions (10) connected to the outer membrane (15).

5. The industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device according to claim 4, characterized in that: The partition (10) separates the cavity formed by the membrane shell (1), the upper water separation plate (5) and the lower water separation plate (6) into a hot water chamber and a cold water chamber from the water inlet pipe (2) to the water outlet pipe (3).

6. The industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device according to claim 4, characterized in that: The cross section of the guide ring rod (12) is semicircular, and gap holes (13) are provided in the middle of the other two guide ring rods (12), and each gap hole (13) corresponds to the water inlet pipe (2) and the water outlet pipe (3) in the horizontal direction.

7. The industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device according to claim 1, characterized in that: A locking top plug (16) and a lower sealing plug (17) are respectively installed at the upper and lower ends of the membrane shell (1), and the locking top plug (16) and the lower sealing plug (17) are used to lock the vertical position of the inner membrane layer (9), and an A inlet and a B outlet are respectively opened on the locking top plug (16) and the lower sealing plug (17).

8. The industrial wastewater thermal gradient temperature-controlled membrane distillation treatment device according to claim 1, characterized in that: Packaging seats (4) are installed at both upper and lower ends of the outer side of the inner film layer (9), and the packaging seats (4) are used to fix the upper water distribution plate (5) and the lower water distribution plate (6).

9. A thermal gradient temperature-controlled membrane distillation process for treating industrial wastewater, comprising: The steps include: Step 1: The hot working medium discharged from the constant temperature water bath enters the through-hole pipe (11) through the A inlet to provide membrane heat, and the wastewater enters the membrane shell (1) from the water inlet pipe (2), is first filtered by the external membrane (15) and filled into the heat capacity cavity; Step 2: The wastewater passes through the membrane shell (1) in a vertical direction and enters the heat capacity chamber. The wastewater is guided by the tangential grooves (7) and the vertical grooves (8) respectively provided on the upper water separation plate (5) and the lower water separation plate (6), and the direction of the wastewater is adjusted from perpendicular to the membrane surface to a rotating inflow entering along the tangential direction of the membrane surface, forming a vortex flow. Step 3: The wastewater passes through the upper water separation plate (5) and the lower water separation plate (6) and enters the inner membrane layer (9) of the heat chamber to complete membrane distillation. Finally, it is discharged from the outlet pipe (3) to complete the purification treatment. The remaining wastewater and hot working medium mixture is discharged from the B outlet through the through-hole pipe (11) and returned to the constant temperature water bath for the circulation supply of hot working medium.

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