Normal-pressure low-temperature evaporation device based on heat pump technology

Abstract

The normal-pressure low-temperature evaporation device based on the heat pump technology comprises a shell and tube heat exchanger, the shell and tube heat exchanger is communicated with a heat exchange pipeline and a mother liquor evaporation pipeline, the mother liquor evaporation pipeline comprises a perforated pipe, a mother liquor water curtain falling at a uniform speed is formed in the perforated pipe, and a filler structure for increasing the evaporation area is arranged below the mother liquor water curtain. A liquid tank is arranged below the filler structure, a gas-liquid separator is arranged above the perforated pipe, and an upper heat exchange structure and a negative pressure fan are arranged above the gas-liquid separator. The mother liquor is forced to circulate and dynamically exchanges heat with a refrigerant through the mother liquor evaporation pipeline and the circulating pump, and the heat exchange speed is higher than that of static heat exchange of a vacuum low-temperature evaporation system. The evaporation area is greatly enlarged through spraying of the perforated pipe, the heat exchange area is further enlarged through the filler layer, the backflow speed of mother liquor is delayed, and the opportunity that water molecules make contact with flowing air is increased. Water molecules can be separated from mother liquor more quickly due to the strong air volume and air speed of the negative pressure fan.

Description

Technical Field

[0001] The present invention belongs to the technical field of atmospheric pressure low-temperature evaporation, and particularly relates to an atmospheric pressure low-temperature evaporation device based on heat pump technology. Background Art

[0002] Currently, all the actually applied heat pump type low-temperature evaporation technologies adopt vacuum low-temperature evaporation technology. Although the heat pump type vacuum low-temperature evaporation technology is the current mainstream process, there are still several technical problems in its system architecture. Among them, the strong dependence on the vacuum pump has become the key pain point restricting the improvement of equipment energy efficiency.

[0003] The working principle of the heat pump type low-temperature evaporation technology is as follows: The mother liquor enters the heating container. When the heat pump operates, the heat generated during the condensation of the refrigerant at the heating end (shell and tube heat exchanger) heats the original liquid through the heat exchanger; in a vacuum environment, the water in the mother liquor boils at a low temperature, and water molecules escape from the mother liquor to generate water vapor and enter the condensation container; when the heat pump operates, the refrigerant at the refrigeration end (evaporator) absorbs the heat in the water vapor during evaporation, and the water vapor loses heat and condenses into water, which enters the water storage container; when the water volume reaches the set value, the water inlet is closed, the vacuum of the water storage container is released, and the drain valve is opened to discharge the condensed water.

[0004] It can be seen from the above working principle that during the working process, since the heat generated by the compressor during operation is greater than the cold generated, an overheater is also needed to consume the excess heat to ensure the normal operation of the compressor. A preheating device is also required in the heating container to first raise the temperature of the mother liquor so that the compressor can be started when heat can be provided to the refrigeration end (evaporator).

[0005] Chinese Patent CN111747468B, a heat pump vacuum low-temperature evaporation and concentration system, discloses an evaporation tank, a heating Carnot cycle system, a negative pressure suction pipeline, and a clean water circulation system. Although it mentions low maintenance costs and long service life, it is still based on a vacuum environment.

[0006] Based on the above problems, there is currently no evaporation device that can efficiently evaporate in an atmospheric pressure low-temperature environment. Summary of the Invention

[0007] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide an atmospheric pressure low-temperature evaporation device based on heat pump technology.

[0008] The technical solution of the present invention is: a normal-pressure low-temperature evaporation device based on heat pump technology, including a shell-and-tube heat exchanger for heat exchange, the shell-and-tube heat exchanger is connected to a heat exchange pipeline and a mother liquor evaporation pipeline, the mother liquor evaporation pipeline includes a perforated pipe connected to the shell-and-tube heat exchanger, a mother liquor water curtain that falls at a uniform speed is formed in the perforated pipe, a packing structure for increasing the evaporation area is arranged below the mother liquor water curtain, a liquid tank is arranged below the packing structure, a gas-liquid separator for gas-liquid separation is arranged above the perforated pipe, an upper heat exchange structure is arranged above the gas-liquid separator, and a negative pressure fan for gas diversion is arranged above the upper heat exchange structure.

[0009] Furthermore, the bottom of the liquid tank is connected to the liquid inlet of the circulation pump, and the liquid outlet of the circulation pump is connected to the shell-and-tube heat exchanger.

[0010] Furthermore, the upper heat exchange structure is a fin heat exchanger, and the arrangement direction of the fins in the fin heat exchanger is the same as the air guiding direction of the negative pressure fan, so that the gas is led out from the gaps between the fins.

[0011] Furthermore, the heat exchange pipes in the fin heat exchanger are connected in series with a compressor, a shell-and-tube heat exchanger, and an expansion valve to form a heat exchange pipeline.

[0012] Furthermore, in the heat exchange pipeline, the refrigerant releases heat at the shell-and-tube heat exchanger and absorbs heat at the fin heat exchanger.

[0013] Furthermore, in the mother liquor evaporation pipeline, the mother liquor absorbs heat and rises in temperature at the shell-and-tube heat exchanger, and releases heat and cools down at the fin heat exchanger, and thus condenses and falls into the gas-liquid separator.

[0014] Furthermore, the perforated pipe includes a water distribution main pipe and a water curtain branch pipe, and the axial water inlet ends of the water curtain branch pipes are connected in parallel to the water distribution main pipe.

[0015] Furthermore, downward water outlets are formed on the pipe wall of the water curtain branch pipe, and the mother liquor flows in a water curtain shape from the water outlets to the packing structure.

[0016] Furthermore, the packing structure includes a packing layer, and the transverse area of the packing layer is larger than the enclosed area of the water curtain branch pipes, so as to increase the evaporation area of the mother liquor falling into it.

[0017] The beneficial effects of the present invention are as follows: In the present invention, the mother liquor is forced to circulate through the mother liquor evaporation pipeline and the circulation pump to dynamically exchange heat with the refrigerant, and the heat exchange speed is higher than the static heat exchange of the vacuum low-temperature evaporation system.

[0018] In the present invention, the spraying of the perforated pipe enlarges the evaporation area by a huge amount. The packing layer not only further increases the heat exchange area, but also delays the reflux speed of the mother liquor, increasing the chance of contact between water molecules and flowing air.

[0019] In the present invention, the strong air volume and wind speed of the negative pressure fan will cause water molecules to break away from the mother liquor faster.

[0020] Compared with vacuum low-temperature evaporation, the above three points of the present invention improve all the water evaporation elements. On the premise that the compressor power remains unchanged, the evaporation efficiency of the present invention is much higher than that of the vacuum low-temperature evaporation system.

[0021] The present invention does not require a vacuum container, greatly reducing the production cost.

[0022] The present invention omits electrical equipment such as vacuum pumps, slag discharge pumps, and pressure sensors, and is more energy-efficient.

[0023] The present invention only needs to control the rotation speeds of the circulation pump and the negative pressure fan to make the unit operate normally, simplifying the control system. Description of the Drawings

[0024] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram of the flow direction of the water collecting tank in the present invention; Wherein: 1 Circulation pump 2 Shell-and-tube heat exchanger 3 Compressor 4 Expansion valve 5 Liquid tank 6 Packing layer 7 Perforated pipe 8 Gas-liquid separator 9 Water collecting tank 10 Drain pipe 11 Finned heat exchanger 12 Negative pressure fan. Detailed Embodiment

[0025] Hereinafter, the present invention will be described in detail with reference to the drawings and embodiments: As Figure 1 shown, a normal-pressure low-temperature evaporation device based on heat pump technology includes a shell-and-tube heat exchanger 2 for heat exchange. The shell-and-tube heat exchanger 2 is connected to a heat exchange pipeline and a mother liquor evaporation pipeline. The mother liquor evaporation pipeline includes a perforated pipe 7 connected to the shell-and-tube heat exchanger 2. A uniform-speed falling mother liquor water curtain is formed in the perforated pipe 7. A packing structure for increasing the evaporation area is arranged below the mother liquor water curtain. A liquid tank 5 is arranged below the packing structure. A gas-liquid separator 8 for gas-liquid separation is arranged above the perforated pipe 7. An upper heat exchange structure is arranged above the gas-liquid separator 8. A negative pressure fan 12 for gas drainage is arranged above the upper heat exchange structure.

[0026] The bottom of the liquid tank 5 is communicated with the liquid inlet of the circulation pump 1, and the liquid outlet of the circulation pump 1 is communicated with the shell-and-tube heat exchanger 2.

[0027] The upper heat exchange structure is a fin heat exchanger 11. The arrangement direction of the fins in the fin heat exchanger 11 is the same as the diversion direction of the negative pressure fan 12, so that the gas is led out from the gaps between the fins.

[0028] The heat exchange tubes in the fin heat exchanger 11 are connected in series with the compressor 3, the shell-and-tube heat exchanger 2, and the expansion valve 4 to form a heat exchange pipeline.

[0029] In the heat exchange pipeline, the refrigerant releases heat at the shell-and-tube heat exchanger 2 and absorbs heat at the fin heat exchanger 11.

[0030] In the mother liquor evaporation pipeline, the mother liquor absorbs heat and heats up at the shell-and-tube heat exchanger 2, and releases heat and cools down at the fin heat exchanger 11, so as to condense and fall into the gas-liquid separator 8.

[0031] The perforated pipe 7 includes a water distribution main pipe and a water curtain branch pipe. The axial water inlet ends of the water curtain branch pipes are connected in parallel with the water distribution main pipe.

[0032] Downward water outlets are formed at the pipe walls of the water curtain branch pipes, and the mother liquor flows towards the packing structure in a water curtain shape from the above-mentioned water outlets.

[0033] The packing structure includes a packing layer 6. The transverse area of the packing layer 6 is larger than the enclosed area of the water curtain branch pipes, so as to increase the evaporation area of the mother liquor falling into it. The transverse area of the packing layer 6 prevents the water curtain from directly falling into the liquid tank 5 without passing through the packing layer 6.

[0034] As an implementation manner, the packing layer 6 is composed of several packings. The laying thickness of the packing layer 6 is designed according to needs. At the same time, the packing layer 6 does not affect the air volume, and the accumulation of the packings is irregular.

[0035] Specifically, the packing layer 6 is a packing for increasing the evaporation area and having good ventilation, and its material may be but is not limited to Pall ring packing.

[0036] Specifically, as an implementation manner, a flow regulating valve is provided in the water distribution main pipe. Correspondingly, flow regulating valves are also provided in each water curtain branch pipe.

[0037] Specifically, in this application, the mother liquor is forced to flow by the circulation pump 1 to form a forced circulation of the mother liquor, which is different from the static heat exchange of the existing evaporation device. This application provides a dynamic heat exchange evaporation process.

[0038] Specifically, the liquid tank 5 is an open-type water collecting tank.

[0039] As a preferred implementation, a groove is formed at the bottom of the liquid tank 5 to facilitate the circulation of the liquid.

[0040] Specifically, the water outlet inlets in the water curtain branch pipes are evenly distributed at equal intervals, and the parallel-connected water curtain branch pipes are also evenly distributed at equal intervals, thus forming a water curtain or a spray shape.

[0041] Specifically, the specific structure of the perforated pipe 7 increases the evaporation area. The packing layer 6 not only further increases the heat exchange area but also delays the reflux speed of the mother liquor and increases the chance of contact between water molecules and flowing air.

[0042] Specifically, the negative pressure fan 12 is located directly above the fin heat exchanger 11. The negative pressure fan 12 allows the air flow to enter from below the packing layer 6 and pass vertically through the packing layer 6, the gas-liquid separator 8, and the fin heat exchanger 11. The strong air volume and air speed will cause the water molecules to break away from the mother liquor faster.

[0043] Specifically, the gas-liquid separator 8 includes a gas channel and a water collection structure from bottom to top.

[0044] More specifically, the water collection structure includes a water collection tank 9, and the water collection tank 9 includes a side water collection tank, a middle water collection tank, and a guiding water collection tank.

[0045] Specifically, the side water collection tank is directly connected to the inner wall of the housing. The side water collection tank is L-shaped and encloses water collection with the inner wall of the housing.

[0046] Specifically, the guiding water collection tank includes an L-shaped water collection part. The L-shaped water collection part is connected to a guiding side wall. The angle between the guiding side wall and the horizontal plane is an acute angle. The vertical projection of the guiding side wall falls into the side water collection tank or the L-shaped water collection part of an adjacent guiding water collection tank. Using a longer guiding side wall can make the liquid falling from the fin heat exchange enter the L-shaped water collection part and prevent the condensed water after heat exchange from entering the packing layer 6.

[0047] Specifically, the guiding water collection tanks are arranged symmetrically left and right.

[0048] Specifically, the middle water collection tank includes a bottom plate, a left guiding side wall, and a right guiding side wall. The bottom plate, the left guiding side wall, and the right guiding side wall enclose to form the middle water collection tank. The left guiding side wall is parallel to the guiding water collection tank on the left side, and the right guiding side wall is parallel to the guiding water collection tank on the right side.

[0049] At the same time, the vertical projections of the above-mentioned left guiding side wall and right guiding side wall fall into the side water collection tank, also preventing the condensed water after heat exchange from entering the packing layer 6.

[0050] Specifically, the middle water collection tank and the guiding water collection tank are connected to the inner wall of the housing through a support frame, and the connection method is not specifically restricted.

[0051] Specifically, the water collecting tank 9 and the drain pipe 10 discharge the condensed water after condensation through the drain pipe 10.

[0052] As an implementation manner, the water collecting tank 9 communicates with the confluence tank / confluence pipeline / water collecting pipeline on the front and rear sides, and converges the condensed water collected in each of the above water collecting tanks 9, and the condensed water after convergence is discharged through the drain pipe 10.

[0053] Specifically, the drain pipe 10 is arranged on the outer wall of the housing.

[0054] Specifically, a processing slope or an installation slope is formed in the confluence tank / confluence pipeline / water collecting pipeline to facilitate the condensed water flowing into the drain pipe 10 during confluence.

[0055] The working process of the present invention is as follows: During operation, the compressor 3, the circulation pump 1, and the negative pressure fan 12 are turned on simultaneously. The mother liquor is forced into the shell and tube heat exchanger 2 (full liquid heat exchanger) through the circulation pump 1, absorbs the heat released during the condensation of the refrigerant in the full liquid heat exchanger, enters the perforated pipe 7, and is sprayed onto the packing layer 6, forming a huge evaporation area of the mother liquor during the above process.

[0056] Under the action of the high-power negative pressure fan 12, air enters from the bottom of the packing layer 6 and meets the heated mother liquor sprayed down. The water molecules in the mother liquor are carried by the strong air volume to form humid air, which passes through the gas-liquid separator 8 at high speed; the water molecules in the humid air are condensed into water droplets by the fin heat exchanger 11 and fall into the water collecting tank 9 of the gas-liquid separator 8 and are discharged.

[0057] In the present invention, the mother liquor is forced to circulate through the mother liquor evaporation pipeline and the circulation pump to dynamically exchange heat with the refrigerant, and the heat exchange speed is higher than the static heat exchange of the vacuum low-temperature evaporation system.

[0058] In the present invention, the spraying of the perforated pipe greatly enlarges the evaporation area. The packing layer not only further increases the heat exchange area, but also delays the backflow speed of the mother liquor and increases the chance of contact between water molecules and flowing air.

[0059] In the present invention, the strong air volume and wind speed of the negative pressure fan will make the water molecules break away from the mother liquor faster.

[0060] Compared with the vacuum low-temperature evaporation, the above three points of the present invention improve all the water evaporation elements. On the premise that the compressor power remains unchanged, the evaporation efficiency of the present invention is much higher than that of the vacuum low-temperature evaporation system.

[0061] The present invention does not require a vacuum container, greatly reducing the production cost.

[0062] The present invention omits electrical equipment such as vacuum pumps, slag discharge pumps, and pressure sensors, and is more energy-saving.

[0063] The present invention only needs to control the rotational speeds of the circulation pump and the negative pressure fan to enable the normal operation of the unit, simplifying the control system.

Claims

1. A normal pressure low temperature evaporation device based on heat pump technology, comprising a shell and tube heat exchanger (2) for heat exchange, characterized in that: The shell and tube heat exchanger (2) is connected to a heat exchange pipeline and a mother liquid evaporation pipeline. The mother liquid evaporation pipeline includes a perforated tube (7) connected to the shell and tube heat exchanger (2). A mother liquid water curtain that falls at a uniform speed is formed in the perforated tube (7). A packing structure that increases the evaporation area is provided below the mother liquid water curtain. A liquid tank (5) is provided below the packing structure. A gas-liquid separator (8) for gas-liquid separation is provided above the perforated tube (7). An upper heat exchange structure is provided above the gas-liquid separator (8). A negative pressure fan (12) for gas drainage is provided above the upper heat exchange structure.

2. According to claim 1, a normal pressure low temperature evaporation device based on heat pump technology is characterized in that: The bottom of the liquid tank (5) is connected to the liquid inlet of the circulation pump (1), and the liquid outlet of the circulation pump (1) is connected to the shell and tube heat exchanger (2).

3. The normal pressure low temperature evaporation device based on heat pump technology according to claim 1 is characterized in that: The upper heat exchange structure is a fin heat exchanger (11), and the arrangement direction of the fins in the fin heat exchanger (11) is consistent with the flow diversion direction of the negative pressure fan (12), so that the gas is drawn out from the gaps between the fins.

4. The normal pressure low temperature evaporation device based on heat pump technology according to claim 3 is characterized in that: The heat exchange tubes in the fin heat exchanger (11) are connected in series with the compressor (3), the shell and tube heat exchanger (2), and the expansion valve (4) to form a heat exchange pipeline.

5. The normal pressure low temperature evaporation device based on heat pump technology according to claim 4 is characterized in that: In the heat exchange pipeline, the refrigerant releases heat at the shell and tube heat exchanger (2) and absorbs heat at the fin heat exchanger (11).

6. The normal pressure low temperature evaporation device based on heat pump technology according to claim 5 is characterized in that: In the mother liquid evaporation pipeline, the mother liquid absorbs heat and increases in temperature in the shell and tube heat exchanger (2), and releases heat and decreases in temperature in the fin heat exchanger (11), thereby condensing and falling into the gas-liquid separator (8).

7. The normal pressure low temperature evaporation device based on heat pump technology according to claim 1 is characterized in that: The perforated pipe (7) comprises a water distribution main pipe and a water curtain branch pipe, and the axial water inlet end of the water curtain branch pipe is connected in parallel to the water distribution main pipe.

8. The normal pressure low temperature evaporation device based on heat pump technology according to claim 7 is characterized in that: A downward water outlet is formed at the pipe wall of the water curtain branch pipe, and the mother liquid flows from the water outlet to the packing structure in a water curtain shape.

9. The normal pressure low temperature evaporation device based on heat pump technology according to claim 8, characterized in that: The packing structure comprises a packing layer (6), wherein the lateral area of ​​the packing layer (6) is larger than the enclosed area of ​​the water curtain branch pipe, thereby increasing the evaporation area of ​​the mother liquid falling therein.

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