A spiral membrane distillation equipment

Abstract

The present invention discloses a spiral membrane distillation device and a method for using the same. The spiral membrane distillation device comprises: a pipeline, a heating device, a water purification tank and a primary raw liquid tank. The pipeline is a spiral structure. A membrane distillation membrane is fixedly installed in the pipeline. The membrane distillation membrane divides the interior of the pipeline into a heating zone and a gas guiding zone. The openings of the heating zone at the two ports of the pipeline are the first port and the second port. The opening of the gas guiding zone at the lower port of the pipeline is the third port. The opening of the gas guiding zone at the upper port of the pipeline is the fourth port. A condensing device is fixedly installed on the top of the primary raw liquid tank. The first port is used to input seawater or industrial water raw liquid into the heating zone. The second port is connected to the primary raw liquid tank. The third port is connected to the water purification tank. The fourth port is used to connect to the condensing device. The heating device is used to heat the heating zone. The centrifugal force generated by the heating zone can increase the speed at which water vapor enters the gas guiding zone from the heating zone, thereby increasing the distillation flux.

Description

Technical Field

[0001] The invention belongs to the technical field of distillation, and in particular relates to a spiral membrane distillation device. Background Art

[0002] With the rapid development of modern industry and population expansion, water shortage has become a serious challenge facing the world. Seawater reserves are abundant, accounting for 97% of the world's surface water content. Utilizing seawater resources through seawater desalination technology is an effective way to solve the water resource problem. At present, seawater desalination processes mainly include multi-stage flash evaporation, multi-effect distillation, reverse osmosis and membrane distillation. Among them, membrane distillation technology uses a high-porosity hydrophobic membrane as a separation medium and the temperature difference on both sides of the membrane as a driving force to transfer fresh water from the salt water side to the cold side through three steps of "evaporation-transfer-condensation", thereby concentrating the salt water and producing fresh water. Since it was first proposed in 1963, it has attracted much attention due to its advantages such as high effluent quality, low operating pressure and low operating temperature. However, the existing membrane distillation equipment for desalination of seawater has the following problems: (1) The equipment occupies a large area and has low space utilization; (2) The energy consumption rate is high, the loss is large, and the utilization rate is extremely low. These problems have, to a certain extent, restricted the industrial implementation of membrane distillation technology in the fields of seawater desalination. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide a spiral membrane distillation device.

[0004] Another object of the present invention is to provide a method for using the spiral membrane distillation equipment.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A spiral membrane distillation device, comprising: a pipeline, a heating device, a water purification tank and a primary raw liquid tank, wherein the pipeline is a spiral structure, and a membrane distillation membrane is fixedly installed in the pipeline, so that the membrane distillation membrane divides the interior of the pipeline into two spaces arranged along the radial direction of the pipeline: a heating zone and a gas guiding zone, wherein the openings of the heating zone located at the two ports of the pipeline are the first port and the second port, the opening of the gas guiding zone located at the lower port of the pipeline is the third port, and the opening of the gas guiding zone located at the upper port of the pipeline is the fourth port;

[0007] The primary raw liquid pool is a sealed cavity, which is used to store seawater or industrial water raw liquid. A condensing device is fixedly installed on the top of the primary raw liquid pool, and the condensing device is used to condense the vapor evaporated in the primary raw liquid pool; the first port is used to input seawater or industrial water raw liquid into the heating zone, and the second port is connected to the primary raw liquid pool and is used to discharge liquid into the primary raw liquid pool; the third port is connected to the clean water pool, and the fourth port is used to connect to the condensed water discharge port of the condensing device; the heating device is used to heat the heating zone.

[0008] In the above technical solution, the heating device is a rod-shaped structure, and the heating device is located at the axis of the spiral structure.

[0009] In the above technical solution, the first port is located above the second port.

[0010] As an implementation, the first port is connected to the primary raw liquid pool and is used to extract seawater or industrial water raw liquid from the primary raw liquid pool.

[0011] As another implementation, it also includes: a non-sealed open primary raw liquid tank, the open primary raw liquid tank is used to place seawater or industrial water raw liquid, the first port is connected to the open primary raw liquid tank, and is used to extract seawater or industrial water raw liquid from the open primary raw liquid tank.

[0012] In the above technical solution, it also includes a first filter membrane for filtering the seawater or industrial water raw liquid entering the open primary raw liquid pool.

[0013] In the above technical solution, the edge of the membrane distillation membrane along the length direction of the pipeline is connected to the inner wall of the pipeline.

[0014] In the above technical solution, the liquid level in the open primary raw liquid pool is higher than the first port.

[0015] The above technical solution also includes: a pressure compensation device installed between the condensation equipment and the gas guide area, and the pressure compensation device is used to introduce gas from the outside of the spiral membrane distillation equipment into the gas guide area.

[0016] The method for using the above-mentioned spiral membrane distillation equipment includes the following steps: the heating device heats the heating zone, the maximum pressure difference between the two sides of the membrane distillation membrane that can withstand is X, and under the premise of keeping the pressure difference between the two sides of the membrane distillation membrane less than X, seawater or industrial water concentrate is introduced into the heating zone.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) The spiral membrane distillation equipment uses a spiral structure to perform membrane distillation on seawater or industrial water, which reduces the floor space and improves space utilization. When the seawater or industrial water flows in the heating zone, the seawater or industrial water in the heating zone will generate centrifugal force due to the spiral structure of the pipeline in the spiral membrane distillation equipment. The centrifugal force will increase the speed at which water vapor enters the gas guide zone from the heating zone, thereby increasing the membrane distillation flux.

[0019] (2) There is a gap between the heating device and the pipeline, and there is still air, which has a heat preservation effect, improves the utilization rate of thermal energy, saves energy consumption and reduces costs.

[0020] (3) Make full use of the waste heat of seawater or industrial water returning from the heating area to the primary stock liquid pool, so that the seawater or industrial water stock liquid evaporates in the primary stock liquid pool to generate water vapor, which is then condensed to provide fluid for the gas guide area, stabilize the pressure difference on both sides of the membrane distillation membrane, greatly improve the utilization rate of thermal energy, and significantly reduce costs.

[0021] (4) Water vapor passes through the air guide area and blows across one side of the membrane distillation membrane, driving the flow rate of the fluid in the air guide area, causing the water vapor evaporated from the heating area to move along with it, accelerating the evaporation effect and increasing the production rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the spiral membrane distillation equipment in Example 3;

[0023] Figure 2 It is a schematic diagram of the structure of the spiral membrane distillation equipment in Example 4;

[0024] Figure 3 It is a schematic diagram of the three-dimensional structure of the pipeline;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the pipeline;

[0026] Figure 5 It is a plan view of the pipeline (a heating device is shown in the figure);

[0027] Figure 6 This is a partial enlarged view of the pipeline (the membrane distillation membrane is shown in the figure).

[0028] Among them, 1 is a pipeline, 1-1 is a heating area, 1-1-1 is a first port, 1-1-2 is a second port, 1-2 is an air guide and flow guide area, 1-2-1 is a third port, 1-2-2 is a fourth port, 2 is a heating device, 3 is a water purification tank, 4 is a primary raw liquid tank, 5 is a membrane distillation membrane, 6 is a condensing device, 6-1 is a water collecting plate, 7 is an open primary raw liquid tank, 8 is a first filter membrane, and 9 is a water pump. DETAILED DESCRIPTION

[0029] The spiral membrane distillation equipment of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Example 1

[0031] A spiral membrane distillation device comprises: a pipeline 1, a heating device 2, a water purification tank 3 and a primary stock solution tank 4. The pipeline 1 is a spiral structure, and a membrane distillation membrane 5 is fixed in the pipeline 1 so that the membrane distillation membrane 5 divides the interior of the pipeline 1 into two spaces arranged radially along the pipeline 1 (such as Figure 6 As shown): heating zone 1-1 and air guiding zone 1-2, the openings of heating zone 1-1 at two ports of pipeline 1 are first port 1-1-1 and second port 1-1-2, the opening of air guiding zone 1-2 at the lower port of pipeline 1 is third port 1-2-1, and the opening of air guiding zone 1-2 at the upper port of pipeline 1 is fourth port 1-2-2 (as shown Figure 3~4 As shown); the membrane distillation membrane can be a super hydrophobic membrane, a super bi-hydrophobic membrane or a Janus membrane.

[0032] The primary stock liquid pool 4 is a sealed cavity, which is used to store seawater or industrial water stock liquid. A condensing device 6 is fixedly installed on the top of the primary stock liquid pool 4, and the condensing device 6 is used to condense the evaporated gas in the primary stock liquid pool 4; the first port 1-1-1 is used to input seawater or industrial water stock liquid (industrial water stock liquid: industrial wastewater) into the heating area 1-1, and the second port 1-1-2 is connected to the primary stock liquid pool 4, and is used to discharge liquid into the primary stock liquid pool 4; the third port 1-2-1 is connected to the clean water pool 3, and the fourth port 1-2-2 is used to be connected to the condensed water discharge port of the condensing device 6; the heating device 2 is used to heat the heating area 1-1.

[0033] The heating zone 1-1 and the air-guiding and flow-guiding zone 1-2 are separated by a membrane distillation membrane 5. The heating device 2 heats the seawater or industrial water stock solution in the heating zone 1-1. Part of the seawater or industrial water stock solution in the heating zone 1-1 evaporates into water vapor under the action of the heating device 2. Under the action of the pressure difference on both sides of the membrane distillation membrane 5, the water vapor in the heating zone 1-1 passes through the membrane distillation membrane 5 and enters the air-guiding and flow-guiding zone 1-2. The air-guiding and flow-guiding zone 1-2 has a condensation effect on the water vapor and at the same time reduces the pressure difference on both sides of the membrane distillation membrane 5.

[0034] The seawater or industrial water stock solution that passes through the heating zone 1-1 returns to the primary stock liquid pool 4. The energy carried by the seawater or industrial water stock solution that returns to the primary stock liquid pool 4 continues to heat the primary stock liquid pool 4, so that water vapor is generated in the primary stock liquid pool 4. The water vapor generated by the seawater or industrial water stock solution in the primary stock liquid pool 4 is condensed through the condensing device 6. Since the primary stock liquid pool 4 is a sealed cavity, driven by the pressure of the water vapor generated by the seawater or industrial water stock solution in the primary stock liquid pool 4, the liquid discharged from the condensed water outlet of the condensing device 6 enters the gas guide and diversion zone 1-2, and finally enters the clean water pool 3 through the third port 1-2-1.

[0035] During the operation of the spiral membrane distillation equipment, there will be a certain pressure difference between the two sides of the membrane distillation membrane 5 .

[0036] The pressure of the heating zone 1-1 on the membrane distillation membrane 5 comes from: (i) the water vapor generated by evaporation of the seawater or industrial water stock solution in the heating zone 1-1 under the action of the heating device 2 and (ii) the centrifugal force of the seawater or industrial water stock solution rotating from top to bottom in the heating zone 1-1. The seawater or industrial water stock solution rotates from top to bottom in the heating zone 1-1, and the potential energy is converted into kinetic energy. The centrifugal force of the seawater or industrial water stock solution increases, causing pressure on the membrane distillation membrane 5, thereby accelerating the water vapor in the heating zone 1-1 to pass through the membrane distillation membrane 5 and enter the gas guide and flow guide zone 1-2.

[0037] The pressure of the gas guiding area 1-2 borne by the membrane distillation membrane 5 comes from: the water vapor that enters the gas guiding area 1-2 from the condensation device 6 and is not completely condensed, the water vapor that enters the gas guiding area 1-2 through the membrane distillation membrane 5, and the condensed water.

[0038] Assuming that the maximum pressure difference between the two sides of the membrane distillation membrane 5 can withstand is X, under the premise that the pressure difference between the two sides of the membrane distillation membrane 5 is less than X, the greater the pressure difference between the two sides of the membrane distillation membrane 5, the higher the distillation efficiency.

[0039] Membrane distillation is a membrane technology that uses a hydrophobic microporous membrane (i.e., membrane distillation membrane) to separate aqueous solutions containing non-volatile solutes. Due to the surface tension of water, liquid water cannot pass through the micropores of the membrane distillation membrane under normal pressure, but water vapor can. When there is a certain temperature difference on both sides of the membrane distillation membrane, due to the difference in pressure, water vapor molecules pass through the micropores of the membrane distillation membrane and condense on the other side of the membrane distillation membrane, and sodium ions, chloride ions, microorganisms, dust, etc. are blocked, causing the solution on one side of the membrane distillation membrane to gradually concentrate.

[0040] Example 2

[0041] like Figure 5As shown, on the basis of Example 1, in order to heat the heating zone 1-1 more evenly, the heating device 2 can be a rod-shaped structure, and the heating device 2 is located at the axis of the spiral structure. The heating method of the heating device 2 can be electromagnetic induction heating, resistance heating, industrial waste gas heating, solar heating and other methods. The heating zone 1-1 and the air guide and flow guide zone 1-2 of the same section of the pipeline 1 are arranged in the horizontal direction, the heating zone 1-1 is close to the axis of the spiral structure, and the air guide and flow guide zone 1-2 is far away from the axis of the spiral structure.

[0042] The first port 1-1-1 is located above the second port 1-1-2.

[0043] The edge of the membrane distillation membrane 5 along the length direction of the pipeline 1 is connected to the inner wall of the pipeline 1. The pipeline 1 can be made of metal.

[0044] The condensation device 6 includes: a water collecting plate 6-1 and a cooling part located above the water collecting plate 6-1. The condensation water outlet is located on one side of the water collecting plate 6-1. The cooling part is a curved plate located on the top of the condensation device 6. Water vapor condenses into water in the cooling part, drips on the water collecting plate 6-1, and then flows into the air guide area 1-2 through the condensation water outlet to participate in the membrane distillation process.

[0045] Example 3

[0046] like Figure 1 As shown, based on Example 2, the first port 1-1-1 is connected to the primary raw liquid tank 4 for extracting seawater or industrial water from the primary raw liquid tank 4, and a water pump 9 is installed between the first port 1-1-1 and the primary raw liquid tank 4.

[0047] The technical solution in this embodiment improves space utilization, reduces equipment production line costs, fully concentrates the primary stock liquid pool 4, and is suitable for extracting substances in the primary stock liquid pool 4, filtering water sources, and other aspects.

[0048] Example 4

[0049] like Figure 2 As shown, on the basis of Example 2, it also includes: a non-sealed open primary stock liquid pool 7 and a first filter membrane 8, the open primary stock liquid pool 7 is used to place seawater or industrial water stock liquid, the first port 1-1-1 is connected to the open primary stock liquid pool 7, and is used to extract seawater or industrial water stock liquid from the open primary stock liquid pool 7. The first filter membrane 8 is used to filter the seawater or industrial water stock liquid entering the open primary stock liquid pool 7, and pass large particles such as mud and sand.

[0050] As the spiral membrane distillation device operates, the water in the open primary stock liquid pool 7 decreases, and the water in the external seawater / wastewater discharge area automatically flows to the open primary stock liquid pool 7 through the first filter membrane 8, and the flow rate of filtered water is not limited by the width of the device. At the same time, it can be designed that the position of the open primary stock liquid pool 7 is higher than the spiral membrane distillation device, so that there is no need to install a water pump, reduce power output, and greatly reduce production costs. Alternatively, a water pump can be installed between the first port 1-1-1 and the open primary stock liquid pool 7.

[0051] When the spiral membrane distillation equipment starts to operate, since the seawater or industrial water raw liquid has just entered the heating zone 1-1, but the water vapor that has not been completely condensed from the condensing device 6, the water vapor that has passed through the membrane distillation membrane 5, and the condensed water have not yet entered the gas guide and flow guide zone 1-2, in order to prevent the membrane distillation membrane 5 from being damaged when the pressure difference between the two sides of the membrane distillation membrane 5 is greater than X (the pressure in the heating zone 1-1 is much greater than the pressure in the gas guide and flow guide zone 1-2), one of the following two methods can be used for pressure compensation:

[0052] 1. Progressive pumping method to compensate pressure (reducing the pressure in the heating zone 1-1): When the spiral membrane distillation equipment starts to operate, the pump 9 extracts a small amount of seawater or industrial water stock solution to reduce the squeezing of the membrane distillation membrane 5 by the seawater or industrial water stock solution in the heating zone 1-1. After the seawater or industrial water stock solution in the heating zone 1-1 is heated, water vapor is generated. The water vapor passes through the membrane distillation membrane 5 and enters the gas guide and flow guide zone 1-2. Under the premise of keeping the pressure difference between the two sides of the membrane distillation membrane 5 less than X, the pumping amount of the pump 9 is gradually increased;

[0053] 2. Install a pressure compensation device to compensate for the pressure in the air guide area 1-2: install a pressure compensation device between the condensing equipment 6 and the air guide area 1-2. Before the spiral membrane distillation equipment starts working, turn on the pressure compensation device. The pressure compensation device allows gas (the gas can be air) to be introduced into the air guide area 1-2 from outside the spiral membrane distillation equipment. The pressure compensation device progressively pressurizes the air guide area 1-2 and turns on the water pump 9 to extract seawater or industrial water. Keep the pressure difference on both sides of the membrane distillation membrane 5 less than X.

[0054] A pressure detection device is installed in the air guiding and flow guiding area 1-2 to detect the pressure in the air guiding and flow guiding area 1-2. A pressure detection device for detecting the pressure in the heating area 1-1 can also be installed in the heating area 1-1, or the pressure in the heating area 1-1 can be calculated by inputting seawater or industrial water raw liquid into the heating area 1-1 at a flow rate.

[0055] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A spiral membrane distillation device, characterized in that: include: A pipeline (1), a heating device (2), a water purification pool (3) and a primary raw liquid pool (4), wherein the pipeline (1) is a spiral structure, and a membrane distillation membrane (5) is fixedly installed in the pipeline (1), so that the membrane distillation membrane (5) divides the interior of the pipeline (1) into two spaces arranged radially along the pipeline (1): a heating zone (1-1) and a gas guiding zone (1-2), the openings of the heating zone (1-1) located at two ports of the pipeline (1) are a first port (1-1-1) and a second port (1-1-2), the opening of the gas guiding zone (1-2) located at the lower port of the pipeline (1) is a third port (1-2-1), and the opening of the gas guiding zone (1-2) located at the upper port of the pipeline (1) is a fourth port (1-2-2); The primary raw liquid pool (4) is a sealed cavity, and is used to store seawater or industrial water raw liquid. A condensing device (6) is fixedly installed on the top of the primary raw liquid pool (4), and the condensing device (6) is used to condense the vapor evaporated in the primary raw liquid pool (4); the first port (1-1-1) is used to input seawater or industrial water raw liquid into the heating zone (1-1), and the second port (1-1-2) is connected to the primary raw liquid pool (4) and is used to discharge liquid into the primary raw liquid pool (4); the third port (1-2-1) is connected to the clean water pool (3), and the fourth port (1-2-2) is used to communicate with the condensed water discharge port of the condensing device (6); the heating device (2) is used to heat the raw liquid in the heating zone (1-1), and the heating device (2) is a rod-shaped structure. The heating device (2) is located at the axis of the spiral structure. The condensation device (6) comprises: a water collecting plate (6-1) and a cooling part located above the water collecting plate (6-1); a condensed water discharge port is located on one side of the water collecting plate (6-1); the cooling part is a curved plate located on the top of the condensation device (6); water vapor condenses into water in the cooling part, drips onto the water collecting plate (6-1), and then enters the air guide and flow guide area (1-2) through the condensed water discharge port to participate in the membrane distillation process.

2. The spiral membrane distillation equipment according to claim 1, characterized in that: The first port (1-1-1) is located above the second port (1-1-2).

3. The spiral membrane distillation device according to any one of claims 1 to 2, characterized in that: The first port (1-1-1) is in communication with the primary raw liquid pool (4) and is used to extract seawater or industrial water raw liquid from the primary raw liquid pool (4).

4. The spiral membrane distillation device according to any one of claims 1 to 2, characterized in that: Also includes: A non-sealed open primary stock liquid pool (7), wherein seawater or industrial water stock liquid is placed in the open primary stock liquid pool (7), and the first port (1-1-1) is connected to the open primary stock liquid pool (7) and is used to extract seawater or industrial water stock liquid from the open primary stock liquid pool (7).

5. The spiral membrane distillation equipment according to claim 4, characterized in that: It also includes a first filtering membrane (8) for filtering seawater or industrial water raw liquid entering the open primary raw liquid pool (7).

6. The spiral membrane distillation equipment according to claim 1, characterized in that: The membrane distillation membrane (5) is connected to the inner wall of the pipeline (1) at an edge along the length direction of the pipeline (1).

7. The spiral membrane distillation equipment according to claim 4, characterized in that: The liquid level in the open primary raw liquid pool (7) is higher than the first port (1-1-1).

8. The spiral membrane distillation equipment according to claim 1, characterized in that: Also includes: A pressure compensation device is installed between the condensation zone and the gas guide and flow guide zone (1-2), and the pressure compensation device is used to introduce gas from the outside of the spiral membrane distillation device into the gas guide and flow guide zone (1-2).

9. The method for using the spiral membrane distillation device according to claim 1, characterized in that: The following steps are involved: The heating device (2) heats the heating zone (1-1), and the maximum pressure difference between the two sides of the membrane distillation membrane (5) is X. Under the premise of keeping the pressure difference between the two sides of the membrane distillation membrane (5) less than X, seawater or industrial water is introduced into the heating zone (1-1).

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