A hydrophobic modified ceramic membrane device for seawater desalination and a modification method thereof

Abstract

The application relates to the technical field of ceramic membrane seawater desalination, and particularly discloses a hydrophobic modified ceramic membrane device for seawater desalination and a modification method thereof. The ceramic membrane device comprises a seawater heating device, a modified ceramic membrane separation device and a steam liquefaction device. The modified ceramic membrane separation device comprises a separation tank and a sealing cover. A first annular baffle is concentrically arranged at the bottom of the separation tank. An annular modified ceramic membrane is arranged in the first annular baffle. A plurality of steam channels are uniformly arranged on the annular modified ceramic membrane. Air inlet holes and air outlet holes are arranged at the upper end and the lower end of the annular modified ceramic membrane respectively and are connected with each steam channel. The ceramic membrane device can not only make the whole device operate efficiently and stably, but also make the high-temperature seawater contact with the outer surface and the inner surface of the ceramic membrane in sequence during the flowing process, so that the acting area of the ceramic membrane and the high-temperature seawater is greatly increased, and the seawater desalination efficiency of the whole device is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic membrane seawater desalination, and in particular discloses a hydrophobically modified ceramic membrane device for seawater desalination and a modification method thereof. Background Art

[0002] Membrane distillation is a new membrane separation technology that can be used in the field of seawater desalination. It uses a hydrophobic porous membrane as a selective barrier between the feed side and the permeate side, and the vapor pressure gradient across the hydrophobic porous membrane as the driving force. During the membrane distillation process, the hydrophobic properties of the membrane material prevent the feed liquid from directly entering the membrane pores, allowing only water and volatile components in the feed liquid to diffuse through the membrane pores in the form of vapor. The vapor is then liquefied on the permeate side, achieving the separation effect.

[0003] Ceramic membranes are recognized as membrane materials with excellent structure, high chemical stability and high thermal stability. They are widely used in membrane separation processes such as microfiltration and ultrafiltration. However, due to their inherent hydrophilic properties, they cannot be used in membrane distillation processes. Therefore, how to hydrophobically modify ceramic membranes and use them in the field of membrane distillation technology to achieve seawater desalination treatment has been a research direction for researchers in this field.

[0004] For example, the utility model patent application number 2018201516321 discloses a membrane distillation device based on a hydrophobic porous ceramic membrane. The membrane distillation device includes a membrane distillation assembly, a feed liquid circulation system and a cooling water circulation system connected to the membrane distillation assembly, and a condensate collection system. The hydrophobically modified porous ceramic membrane is nanoscale and conformally coated, without changing the internal structure, pore structure, and surface structure of the raw material. The condensation wall is made of a hydrophobically modified material. The porous ceramic membrane in this utility model is a hydrophobically modified ceramic membrane. When used in seawater desalination and desalination processes, it can achieve a desalination rate exceeding 99%. However, because the membrane distillation device is equipped with a flat ceramic membrane in the membrane distillation assembly, the heated seawater vapor can only enter from one side of the ceramic membrane during seawater desalination, resulting in low utilization of the effective separation area of ​​the ceramic membrane. At the same time, the vapor pressure difference between the two sides of the membrane distillation device is small, resulting in a low rate of seawater vapor passing through the micropores in the ceramic membrane, thus resulting in poor desalination efficiency. In response to the above-mentioned shortcomings of existing membrane distillation devices based on hydrophobic porous ceramic membranes, the present application proposes a hydrophobically modified ceramic membrane device for seawater desalination and a modification method thereof that can effectively solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a hydrophobically modified ceramic membrane device for seawater desalination and a modification method thereof, so as to solve the shortcomings of the existing membrane distillation device based on hydrophobic porous ceramic membrane mentioned in the background art.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for modifying a hydrophobically modified ceramic membrane for seawater desalination comprises the following steps:

[0008] 1) A ceramic membrane with an annular structure is selected and multiple steam channels are evenly opened. Then, air outlet holes and air inlet holes connected to the corresponding steam channels are opened at the upper and lower ends of the inner wall of the ceramic membrane;

[0009] 2) The ceramic membrane processed in step 1 is first ultrasonically cleaned, and then sequentially washed with ethanol and pure water several times, and then dried after the ceramic membrane is cleaned;

[0010] 3) dissolving methyltrichlorosilane in anhydrous ethanol to prepare a modified solution, and then performing magnetic stirring to form a uniform and stable chlorosilane solution;

[0011] 4) placing the ceramic membrane dried in step 2 in a chlorosilane solution and allowing it to react for a period of time;

[0012] 5) The ceramic membrane after the reaction in step 4 is taken out, cleaned with anhydrous ethanol and dried, then rinsed with pure water, and finally heat treated for a period of time.

[0013] Preferably, the heat treatment condition in step 5 is heat treatment at 70° C. for 30 hours, followed by natural cooling to room temperature.

[0014] The present invention also discloses a ceramic membrane device for seawater desalination using the modified ceramic membrane, comprising a seawater heating device, a modified ceramic membrane separation device and a steam liquefaction device, wherein a hot water pipe is provided between the seawater heating device and the modified ceramic membrane separation device, and an infusion pump is provided on the hot water pipe, the modified ceramic membrane separation device comprises a separation tank and a sealing cover, a first annular baffle is concentrically provided at the bottom of the separation tank, an annular modified ceramic membrane is provided inside the first annular baffle, and a plurality of steam passages are uniformly provided on the annular modified ceramic membrane. Channel, the upper and lower ends of the inner wall of the annular modified ceramic membrane are respectively provided with air inlet holes and air outlet holes connected to each steam channel, each of the air inlet holes is connected to an air intake branch pipe, and the ends of several of the air intake branch pipes are commonly connected to an air intake main pipe extending from the lower end of the separation tank, each of the air outlet holes is connected to an air extraction branch pipe, and the ends of several of the air extraction branch pipes are commonly connected to an air extraction main pipe extending from the sealing cover, the end of the air extraction main pipe is connected to the lower end of the steam liquefaction device, and the upper end of the steam liquefaction device is connected to an air extraction pump through an air pipe;

[0015] The upper and lower ends of the annular modified ceramic membrane are respectively connected to a first disc and a second disc, and the first disc and the second disc are both provided with rubber blocks for sealing the ends of the steam channel. The second disc is connected to a second annular baffle extending into the annular modified ceramic membrane, and a liquid inlet hole is provided on the second disc located in the second annular baffle. The second disc located between the modified ceramic membrane separation device and the second annular baffle is connected to a concentrated liquid discharge pipe extending out of the separation tank.

[0016] As a further arrangement of the above scheme, the upper ends of the first annular baffle and the second annular baffle are both connected with an inclined guide ring plate extending toward the annular modified ceramic membrane, and the horizontal height of the inclined guide ring plate on the second annular baffle is lower than that of the inclined guide ring plate on the first annular baffle.

[0017] As a further configuration of the above solution, a sealing rubber ring is provided at the connection between the second annular baffle and the annular modified ceramic membrane.

[0018] As a further configuration of the above solution, a control valve is provided at the lower end of the concentrate discharge pipe, and a secondary heater is provided on the bottom wall of the separation tank.

[0019] As a further configuration of the above solution, a temperature sensor is provided at the lower end of the separation tank, and a flow meter is provided on the hot water pipe. Both the temperature sensor and the flow meter are electrically connected to the control box on the rack.

[0020] As a further configuration of the above solution, the outer surface of the separation tank is provided with a heat-insulating layer.

[0021] As a further arrangement of the above scheme, the steam liquefaction device includes a vertically arranged liquefaction tank, the upper end of the liquefaction tank is connected to an end cover, the lower end is connected to a liquid collecting hopper, the end of the exhaust main pipe is connected to the side of the liquid collecting hopper, the air pipe is connected to the top of the end cover, a condenser assembly is provided in the liquefaction tank, and a coolant inlet pipe and a coolant discharge pipe are respectively provided at the upper and lower ends of the side of the liquefaction tank.

[0022] As a further arrangement of the above scheme, the condenser assembly includes an upper sealing plate and a lower sealing plate, and the upper sealing plate and the lower sealing plate respectively seal the upper and lower ports of the liquefaction tank, and a spiral guide vane is arranged between the upper sealing plate and the lower sealing plate, and a plurality of condensation tubes are arranged on the spiral guide vane and pass through the upper sealing plate and the lower sealing plate.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The ceramic membrane device disclosed in the present invention adopts a hydrophobically modified annular ceramic membrane when performing seawater desalination treatment, and then a plurality of steam channels are evenly opened on the annular ceramic membrane. The steam channels use negative pressure suction to make the gas inside the steam channels flow at a high speed, resulting in an increase in the pressure difference between the inside and outside of the steam channels. The high-temperature seawater in contact with the surface of the ceramic membrane can quickly pass through the micropores on the ceramic membrane during the flow process, and then enter the steam liquefaction device under the action of the airflow to condense and liquefy to produce fresh water, so that the entire device can operate efficiently and stably.

[0025] 2) The ceramic membrane device of the present invention also uses the design of two inner and outer annular baffles and the annular structure of the ceramic membrane itself to enable high-temperature seawater to contact the outer surface and inner surface of the ceramic membrane in turn during the flow process, thereby greatly increasing the interaction area between the ceramic membrane and the high-temperature seawater, and further improving the seawater desalination efficiency of the entire device.

[0026] 3) The present invention further provides a flow meter, a temperature sensor, and a secondary heater to detect the status of the distillation and desalination of high-temperature seawater. The control box can then promptly start the secondary heater to heat the seawater in the modified ceramic membrane separation device, so that the high-temperature seawater can always maintain the distillation temperature during the interaction with the annular modified ceramic membrane, generating more steam. More steam can maximize the vapor-liquid efficiency of the entire ceramic membrane, allowing the entire ceramic membrane device to perform seawater desalination at the maximum rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 creative work.

[0028] Figure 1 This is a schematic diagram of the front structure of the ceramic membrane device of the present invention;

[0029] Figure 2 This is a schematic diagram of the back structure of the ceramic membrane device of the present invention;

[0030] Figure 3 Schematic diagram of the internal planar structure of the modified ceramic membrane separation device of the present invention;

[0031] Figure 4 This is a schematic diagram of the three-dimensional assembly structure of the separation tank, sealing cover, and annular modified ceramic membrane in the present invention;

[0032] Figure 5 This is a schematic diagram of the three-dimensional assembly structure of the first and second discs and the annular modified ceramic membrane in the present invention;

[0033] Figure 6 Schematic diagram of a three-dimensional partial cross-sectional structure of the annular modified ceramic membrane of the present invention;

[0034] Figure 7 It is a schematic diagram of the three-dimensional assembly structure of the steam liquefaction device in the present invention;

[0035] Figure 8 Schematic diagram of the three-dimensional structure of the upper and lower sealing plates, spiral guide vanes, and condensation tubes in the present invention

[0036] Figure 9 It is a plan view of the modified ceramic membrane separation device of the present invention when performing gas-liquid separation.

[0037] in:

[0038] 1-seawater heating device, 2-modified ceramic membrane separation device, 3-steam liquefaction device, 4-hot water pipe, 5-infusion pump, 6-air pipe, 7-vacuum pump, 8-flow meter, 9-rack, 10-control box, 11-filter;

[0039] 201-separation tank, 202-sealing cover, 203-first annular baffle, 204-annular modified ceramic membrane, 2041-steam channel, 2042-air inlet hole, 2043-air outlet hole, 205-inlet branch pipe, 206-inlet main pipe, 207-exhaust branch pipe, 208-exhaust main pipe, 209-first disc, 210-second disc, 211-rubber block, 212-second annular baffle, 213-concentrate discharge pipe, 214-oblique guide ring plate, 215-sealing rubber ring, 216-control valve, 217-secondary heater;

[0040] 301-liquefaction tank, 302-end cover, 303-liquid collecting hopper, 304-upper sealing plate, 305-lower sealing plate, 306-spiral guide vane, 307-condensation tube array. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0042] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. Figures 1 to 9 , and describes the application in detail with reference to embodiments.

[0043] Example 1

[0044] Example 1 discloses a method for hydrophobic modification of a ceramic membrane for seawater desalination, comprising the following steps:

[0045] S1: A ceramic membrane with an annular structure is selected, and multiple steam channels are opened in an annular array on the ceramic membrane. Then, air outlet holes and air inlet holes connected to the corresponding steam channels are opened at both ends of the inner wall of the ceramic membrane (see the attached Figure 6 ).

[0046] S2: The ceramic membrane processed in step 1 is ultrasonically cleaned for 10 minutes to remove surface impurities and to generate more hydroxyl groups on the inner and outer alumina membrane surfaces of the ceramic membrane. The cleaned ceramic membrane is then placed in ethanol and pure water for three times in sequence. After cleaning, it is placed in a 100°C oven for drying for 6 hours.

[0047] S3: Methyltrichlorosilane was dissolved in anhydrous ethanol to prepare two modified solutions with concentrations of 0.1 mol / L and 0.2 mol / L. The modified solutions were stirred in a constant temperature water bath with a magnetic stirring pot for 12 h at room temperature to form a uniform and stable chlorosilane solution.

[0048] S4: The two ceramic membranes dried in step 2 were placed in two modification solutions with concentrations of 0.1 mol / L and 0.2 mol / L respectively for immersion reaction for 24 hours.

[0049] S5: The ceramic membrane treated in step 4 is cleaned with anhydrous ethanol and dried, and the process is repeated three times. Finally, the modified membrane is rinsed with pure water five times until the organic solvent on the surface is completely cleaned. The soaked and rinsed ceramic membrane is then placed in an oven and heat treated at 70°C for 30 hours, and then naturally cooled to room temperature.

[0050] Finally, the JY-82B video contact angle meter was used to measure the changes in the water contact angle on the surface of the modified ceramic membrane. It was found that the average contact angles of the two modified ceramic membranes were 82.23° and 88.32°, respectively, indicating that the modified ceramic membrane has relatively excellent hydrophobic properties.

[0051] Example 2

[0052] Example 2 discloses a ceramic membrane device for seawater desalination using the hydrophobic modified ceramic membrane of Example 1. Figure 1 and attached Figure 2The main body of the device comprises a seawater heating device 1, a modified ceramic membrane separation device 2, a steam liquefaction device 3, a rack 9 and a control box 10, wherein the modified ceramic membrane separation device 2, the steam liquefaction device 3 and the control box 10 are arranged on the rack 9. A hot water pipe 4 is arranged between the seawater heating device 1 and the modified ceramic membrane separation device 2, and a liquid delivery pump 5 is arranged on the hot water pipe 4, so that the high-temperature seawater boiled in the seawater heating device 1 is sent to the modified ceramic membrane separation device 2 through the action of the liquid delivery pump 5. In order to monitor the delivery amount of the high-temperature seawater, a flow meter 8 is also arranged on the hot water pipe 4, and the flow meter 8 is electrically connected with the control box 10.

[0053] Reference is made to the accompanying drawings Figure 3 ~ attached Figure 6 The modified ceramic membrane separation device 2 comprises a separation tank 201 and a sealing cover 202, and the sealing cover 202 is detachably connected with the upper end opening of the separation tank 201, so as to facilitate the cleaning of the inside of the separation tank 201. A first annular baffle 203 is arranged concentrically at the bottom of the separation tank 201, and an annular modified ceramic membrane 204 is arranged inside the first annular baffle 203. A plurality of steam passages 2041 penetrating up and down are uniformly arranged on the annular modified ceramic membrane 204, and a plurality of air inlet holes 2042 and air outlet holes 2043 are arranged at the lower end and the upper end of the inner wall of the annular modified ceramic membrane 204, and the air inlet holes 2042 and the air outlet holes 2043 are respectively connected with each steam passage 2041.

[0054] An air inlet branch pipe 205 is connected with each air inlet hole 2042, and the end portions of a plurality of air inlet branch pipes 205 are jointly connected with an air inlet main pipe 206, and the air inlet main pipe 206 extends out of the lower end of the separation tank 201, and in order to filter the entering air, a filter 11 is arranged at the outer end portion of the air inlet main pipe 206.

[0055] An exhaust branch pipe 207 is connected to each air outlet hole 2043, and the ends of several exhaust branch pipes 207 are commonly connected to an exhaust main pipe 208. The exhaust main pipe 208 is extended out of the upper end of the sealing cover 202, and the end of the exhaust main pipe 208 is connected to the lower end of the steam liquefaction device 3, and then an exhaust pump 7 is connected to the upper end of the steam liquefaction device 3 through the air pipe 6. The above-mentioned structural design of the annular modified ceramic membrane 204 enables each steam channel 2041 to be evacuated under the action of the vacuum pump 7, so that the gas is filtered by the filter 11 and then enters each steam channel 2041 through the air intake main pipe 206 and the air intake branch pipe 205. Then the air flow flows from bottom to top in the steam channel 2041, so that the gas pressure difference between the steam channel 2041 and the two sides of the annular modified ceramic membrane 204 increases, and the steam in the high-temperature seawater enters the steam channel 2041 through the micropores in the annular modified ceramic membrane 204, and then the steam enters the steam liquefaction device 3 from the air extraction branch pipe 207 and the air extraction main pipe 208 together with the air flow for condensation and liquefaction, thereby producing fresh water.

[0056] A first disc 209 and a second disc 210 are connected to the upper and lower ends of the annular modified ceramic membrane 204, respectively. Rubber blocks 211 are provided on both the first and second discs 209 and 210 to seal the ends of the steam channel 2041. Furthermore, to ensure a tight seal between the second disc 210 and the lower end of the annular modified ceramic membrane 204, a sealing rubber ring 215 is provided at the junction of the second annular baffle 212 and the annular modified ceramic membrane 204. A second annular baffle 212 is connected to the second disc 210, extending into the annular modified ceramic membrane 204. A liquid inlet is provided on the second disc 210, located within the second annular baffle 212. Furthermore, a concentrate discharge pipe 213 extending from the separation tank 201 is connected to the second disc 210 between the modified ceramic membrane separation device 2 and the second annular baffle 212. A control valve 216 is provided at the outer end of the concentrate discharge pipe 213.

[0057] During the seawater separation and desalination process, the modified ceramic membrane separation device 2 in this embodiment delivers the boiling seawater in the seawater heating device 1 into the annular space between the separation tank 201 and the first annular baffle 203 through the infusion pump 5 and the hot water pipe 4. As the high-temperature seawater is continuously added, the seawater will flow down from the upper end of the first annular baffle 203 and enter the annular space between the first annular baffle 203 and the outer wall of the annular modified ceramic membrane 204. At this time, the steam in the high-temperature seawater will enter the steam channel 2041 through the micropores on the membrane surface. As high-temperature seawater continues to be added, the high-temperature seawater will enter the columnar space enclosed by the second annular baffle 212 through the liquid inlet hole on the second disc 210, and then flow down from the upper end of the second annular baffle 212 into the annular space between the second annular baffle 212 and the inner wall of the annular modified ceramic membrane 204, and interact with the inner wall of the annular modified ceramic membrane 204. At this time, the water vapor in the high-temperature seawater will continue to pass through the inner wall of the annular modified ceramic membrane 204 and enter the steam channel 2041 (see Appendix Figure 9 ), and the concentrated liquid after separation will be discharged from the concentrated liquid discharge pipe 213 for circulation heating use.

[0058] In addition, this embodiment also features an oblique guide ring plate 214 extending toward the annular modified ceramic membrane 204, connected to the upper ends of both the first annular baffle 203 and the second annular baffle 212. The oblique guide ring plate 214 on the second annular baffle 212 is positioned at a lower level than the oblique guide ring plate 214 on the first annular baffle 203. The design of the oblique guide ring plate 214 enables the high-temperature seawater to form a waterfall during its initial fall, thereby accelerating the escape of steam from the seawater. Furthermore, to ensure that the distillation temperature is maintained during the interaction between the seawater and the annular modified ceramic membrane 204, an insulating layer is provided on the outer surface of the separation tank 201 to prevent heat loss from the high-temperature seawater. A temperature sensor (not shown) electrically connected to the control box 10 is provided at the lower end of the separation tank 201. A secondary heater 217 is also provided on the bottom wall of the separation tank 201. The temperature sensor monitors the temperature of the high-temperature seawater in real time, and the secondary heater 217 then performs secondary heating on the separation tank 201 to maintain it within the stable distillation range, thereby improving the desalination efficiency.

[0059] Reference Attachment Figure 2 , Attachment Figure 7 and attached Figure 8 The steam liquefaction device 3 includes a vertically arranged liquefaction tank 301, the upper end of the liquefaction tank 301 is connected to the end cover 302, and the lower end is connected to the liquid collecting hopper 303, and then the end of the exhaust main pipe 208 is connected to the side of the liquid collecting hopper 303, and the air pipe 6 is connected to the top of the end cover 302.

[0060] A condenser assembly is installed in the liquefaction tank 301. Coolant inlet and outlet pipes are located at the upper and lower ends of the sides of the liquefaction tank 301, respectively. Specifically, the condenser assembly includes an upper sealing plate 304 and a lower sealing plate 305, which seal the upper and lower ports of the liquefaction tank 301, respectively. A spiral guide vane 306 is installed between the upper and lower sealing plates 304 and 305. Multiple condenser tubes 307 are installed on the spiral guide vane 306, extending through the upper and lower sealing plates 304 and 305. The structural design of the above-mentioned steam liquefaction device 3 is such that when high-temperature steam enters the lower end of the liquefaction tank 301 along with the air flow, the negative pressure of the vacuum pump will cause the high-temperature steam to flow into the condensation tube 307 along with the air flow. At the same time, the coolant inlet pipe and the coolant discharge pipe can continuously pass circulating cooling water between the upper sealing plate 304 and the lower sealing plate 305 to keep the condensation tube 307 at a low temperature. When the high-temperature steam is in the condensation tube 307, it will contact its inner wall and be liquefied. The liquefied fresh water will flow downward under the action of gravity and gather in the liquid collecting hopper 303, and the fresh water can be discharged and collected in a direction by the liquid collecting hopper 303.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for modifying a hydrophobically modified ceramic membrane for seawater desalination, characterized in that: The steps include: Step 1: Select a ceramic membrane with an annular structure and evenly open multiple steam channels. Then, open air outlet holes and air inlet holes connected to the corresponding steam channels at the upper and lower ends of the inner wall of the ceramic membrane. Step 2: The ceramic membrane processed in step 1 is first ultrasonically cleaned, and then sequentially placed in ethanol and pure water for several times. After the ceramic membrane is cleaned, it is dried; Step 3: dissolving methyltrichlorosilane in anhydrous ethanol to prepare a modified solution, and then performing magnetic stirring to form a uniform and stable chlorosilane solution; Step 4: placing the ceramic membrane dried in step 2 in a chlorosilane solution and allowing it to react for a period of time; Step 5: Take out the ceramic membrane after the reaction in step 4, clean it with anhydrous ethanol and dry it, then rinse it with pure water, and finally heat treat it for a period of time.

2. The method for modifying a hydrophobically modified ceramic membrane for seawater desalination according to claim 1, wherein: The heat treatment condition in step 5 is to heat treat at 70° C. for 30 hours and then cool naturally to room temperature.

3. A ceramic membrane device for seawater desalination based on the ceramic membrane modification method according to any one of claims 1 to 2, comprising a seawater heating device (1), a modified ceramic membrane separation device (2) and a steam liquefaction device (3), wherein a hot water pipe (4) is provided between the seawater heating device (1) and the modified ceramic membrane separation device (2), and an infusion pump (5) is provided on the hot water pipe (4), characterized in that: The modified ceramic membrane separation device (2) comprises a separation tank (201) and a sealing cover (202), wherein a first annular baffle (203) is concentrically arranged at the bottom of the separation tank (201), an annular modified ceramic membrane (204) is arranged inside the first annular baffle (203), a plurality of steam channels (2041) extending vertically therethrough are uniformly provided on the annular modified ceramic membrane (204), an air flow inlet (2042) and an air flow outlet (2043) connected to each steam channel (2041) are respectively provided at the upper and lower ends of the inner wall of the annular modified ceramic membrane (204), each of the steam channels (2041) being connected to the first annular baffle (203), and a plurality of steam channels (2041) being uniformly provided on the annular modified ceramic membrane (204). Each air inlet hole (2042) is connected to an air inlet branch pipe (205), and the ends of several air inlet branch pipes (205) are commonly connected to an air inlet main pipe (206) provided at the lower end of the separation tank (201). Each air outlet hole (2043) is connected to an air extraction branch pipe (207), and the ends of several air extraction branch pipes (207) are commonly connected to an air extraction main pipe (208) extending from the sealing cover (202). The end of the air extraction main pipe (208) is connected to the lower end of the steam liquefaction device (3), and the upper end of the steam liquefaction device (3) is connected to an air extraction pump (7) via an air pipe (6). The upper and lower ends of the annular modified ceramic membrane (204) are respectively connected to a first disc (209) and a second disc (210), and the first disc (209) and the second disc (210) are both provided with a rubber block (211) for sealing the end of the steam channel (2041), and the second disc (210) is connected to a second annular baffle (212) extending into the annular modified ceramic membrane (204), and a liquid inlet hole is provided on the second disc (210) located in the second annular baffle (212), and a concentrated liquid discharge pipe (213) extending out of the separation tank (201) is connected to the second disc (210) located between the modified ceramic membrane separation device (2) and the second annular baffle (212).

4. The ceramic membrane device for seawater desalination according to claim 3, characterized in that: The upper ends of the first annular baffle (203) and the second annular baffle (212) are both connected to an inclined guide ring plate (214) extending toward the annular modified ceramic membrane (204), and the horizontal height of the inclined guide ring plate (214) on the second annular baffle (212) is lower than that of the inclined guide ring plate (214) on the first annular baffle (203).

5. The ceramic membrane device for seawater desalination according to claim 3, characterized in that: A sealing rubber ring (215) is provided at the connection between the second annular baffle (212) and the annular modified ceramic membrane (204).

6. The ceramic membrane device for seawater desalination according to claim 3, characterized in that: A control valve (216) is provided at the lower end of the concentrated liquid discharge pipe (213), and a secondary heater (217) is provided on the bottom wall of the separation tank (201).

7. The ceramic membrane device for seawater desalination according to claim 6, characterized in that: A temperature sensor is provided at the lower end of the separation tank (201), and a flow meter (8) is provided on the hot water pipe (4). Both the temperature sensor and the flow meter (8) are electrically connected to a control box (10) on the frame (9).

8. The ceramic membrane device for seawater desalination according to claim 3, characterized in that: The outer surface of the separation tank (201) is provided with a heat-insulating layer.

9. The ceramic membrane device for seawater desalination according to claim 3, characterized in that: The steam liquefaction device (3) comprises a vertically arranged liquefaction tank (301), the upper end of the liquefaction tank (301) is connected to an end cover (302), and the lower end is connected to a liquid collecting hopper (303), the end of the exhaust main pipe (208) is connected to the side of the liquid collecting hopper (303), the air pipe (6) is connected to the top of the end cover (302), a condenser assembly is provided in the liquefaction tank (301), and a coolant inlet pipe and a coolant discharge pipe are respectively provided at the upper and lower ends of the side of the liquefaction tank (301).

10. The ceramic membrane device for seawater desalination according to claim 9, characterized in that: The condenser assembly comprises an upper sealing plate (304) and a lower sealing plate (305), and the upper and lower ports of the liquefaction tank (301) are sealed by the upper sealing plate (304) and the lower sealing plate (305), respectively. A spiral guide vane (306) is provided between the upper sealing plate (304) and the lower sealing plate (305), and a plurality of condensation tubes (307) penetrating the upper sealing plate (304) and the lower sealing plate (305) are provided on the spiral guide vane (306).

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