A radioactive concentrate vacuum drying system

Abstract

The application discloses a kind of radioactive concentrate liquid vacuum drying systems, including drying box, water-cooled heat pump unit, condensing device, water tank, waste discharge outlet, vacuum pump;Water-cooled heat pump unit includes heating coil, condenser, expansion valve, evaporator, compressor, heating coil is located in drying box, the outlet end of heating coil is connected with the inlet end of condenser, the coolant outlet end of condenser is connected with the inlet end of heating coil, the outlet end of evaporator is connected with compressor, the outlet end of compressor is connected with condenser, expansion valve is equipped on the connecting pipeline of condenser and evaporator, the outlet of evaporator is connected with condensing device, the outlet of condensing device is connected with water tank, the outlet of water tank is connected with evaporator, vacuum pump is equipped on the connecting pipeline of drying box and condensing device, waste discharge outlet is located at the rear end of condensing device.The application relies on the pressure difference between concentrate liquid and air in drying box to discharge moisture, removes the cold energy generated at the evaporator end, increases energy reuse, and reduces loss.

Description

Technical Field

[0001] This invention relates to the field of vacuum drying technology, and more specifically to a vacuum drying system for radioactive concentrates. Background Technology

[0002] To meet the requirements for the disposal of radioactive waste liquid, the concentrated liquid after evaporation needs to be stabilized. Currently, the traditional cement solidification process is mainly used in China. However, this process is a volume expansion process, which is not conducive to minimizing waste and will increase disposal costs.

[0003] In-tank drying, as an effective wastewater treatment technology, is suitable for treating radioactive wastewater with high salinity and has been successfully applied in several nuclear power plants. Currently, the heating methods for in-tank drying mainly include electric heating, hot air drying, and microwave drying. Electric heating in-tank drying technology is mature and has a simple structure and process, but it suffers from high energy consumption, uneven drying, wall adhesion, and long drying cycles. Hot air in-tank drying equipment has a simple structure and is easy to maintain; multiple tanks can be arranged to increase drying output, but it still suffers from uneven drying, wall adhesion, and long drying cycles. Microwave in-tank drying offers fast drying speed, uniform heating, and high thermal energy utilization, but it has high equipment costs, and the moisture content near the tank wall is relatively high, requiring special sealing methods to prevent microwave leakage.

[0004] Therefore, this patent application is filed. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a vacuum drying system for radioactive concentrates. This system relies on the pressure difference between the concentrate and the air inside the drying chamber to remove moisture from the concentrate, thus solving the problems of incomplete drying and excessive free water in conventional drying methods. This enhances the drying effect on radioactive concentrates and allows the cooling energy generated at the evaporator end to be carried away sequentially by a condenser and a water tank, increasing energy reuse and reducing losses.

[0006] A vacuum drying system for radioactive concentrate includes a drying chamber, a water-cooled heat pump unit, a condenser, a water tank, a waste discharge outlet, and a vacuum pump.

[0007] The water-cooled heat pump unit includes a heating coil, a condenser, an expansion valve, an evaporator, and a compressor. The heating coil is located inside the drying chamber. The outlet end of the heating coil is connected to the inlet end of the condenser, and the coolant outlet end of the condenser is connected to the inlet end of the heating coil. The outlet end of the evaporator is connected to the compressor, and the outlet end of the compressor is connected to the condenser. An expansion valve is installed on the connecting pipe between the condenser and the evaporator. The outlet of the evaporator is connected to the condensing device, and the outlet of the condensing device is connected to the water tank. The outlet of the water tank is connected to the evaporator. A vacuum pump is installed on the connecting pipe between the drying chamber and the condensing device. The waste discharge outlet is located at the waste outlet end of the condensing device.

[0008] In this embodiment of the invention, the vacuum drying system, through the coordinated operation of a condenser, expansion valve, evaporator, and compressor, relies on the pressure difference between the concentrated liquid and the air inside the drying chamber to expel moisture from the concentrated liquid. This solves the problems of incomplete drying and excessive free water in conventional drying methods, enhancing the drying effect on radioactive concentrated liquids. Simultaneously, a condensing device is connected to the outlet of the evaporator, and the condensed water is fed into a water tank. This allows the cooling energy generated at the evaporator end to be carried away sequentially by the condensing device and the water tank, increasing energy reuse and reducing losses.

[0009] In an optional embodiment, the drying chamber is equipped with a first temperature sensor, a feed regulating valve, an air inlet regulating valve, and a negative pressure gauge.

[0010] In an optional embodiment, a second temperature sensor and a first flow meter are provided on the connecting pipe between the outlet end of the heating coil and the condenser, and a first circulation pump and a third temperature sensor are provided on the connecting pipe between the condenser and the inlet end of the heating coil.

[0011] In an optional embodiment, a fourth temperature sensor is provided on the connecting pipe between the evaporator and the condensing device, a second circulation pump is provided on the connecting pipe between the condensing device and the water tank, and a second flow meter and a fifth temperature sensor are provided on the connecting pipe between the water tank and the evaporator.

[0012] In an optional embodiment, a third flow meter is provided on the connecting pipeline between the vacuum pump and the condensation device.

[0013] In this embodiment of the invention, by arranging various thermometers, flow meters, etc., the temperature changes at each inlet and outlet end and the water flow changes in each inlet and outlet pipeline are monitored in real time, providing feedback for the control of the water-cooled heating unit, so as to better improve the control efficiency.

[0014] In an optional embodiment, the waste discharge outlet includes a waste gas discharge outlet and a waste liquid discharge outlet, both of which are located at the corresponding outlets of the condensation device.

[0015] In an optional embodiment, the drying chamber is provided with a pull-out door, and a drying barrel is provided inside the drying chamber. The drying barrel has an opening for adding radioactive concentrate, and the drying barrel is attached to the heating coil.

[0016] In an optional embodiment, the heating coil is arranged in a serpentine pattern, and the heating coil is radially semicircular and fits against the outside of the drying barrel.

[0017] In an optional embodiment, the drying drum is fixed on a rotating tray, the bottom of the rotating tray is provided with a rotating motor, and the drying chamber is provided with a roller conveyor, the rotating motor and the roller conveyor being slidably engaged.

[0018] In this embodiment of the invention, the heating coil is folded along half of the drying drum and combined with a rotating tray and a rotating motor to make the drying drum rotate, so that the drying drum is heated evenly and the heating area of ​​the standard drum is increased, effectively enhancing the drying effect.

[0019] In an optional embodiment, a pressure monitoring gauge is provided inside the rotating tray.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] This invention provides a vacuum drying system for radioactive concentrate. Through the coordinated operation of a condenser, expansion valve, evaporator, and compressor, the system utilizes the pressure difference between the concentrate and the air inside the drying chamber to remove moisture from the concentrate. This solves the problems of incomplete drying and excessive free water content in conventional drying methods, thus enhancing the drying effect on radioactive concentrate. Simultaneously, a condensing device is connected to the evaporator outlet, and the condensed water is fed into a water tank. This allows the cooling energy generated at the evaporator end to be carried away sequentially by the condensing device and the water tank, increasing energy reuse and reducing losses. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0023] Figure 1 This is a schematic diagram of a vacuum drying system for radioactive concentrate provided by the present invention.

[0024] In the diagram: 1-Tightening door; 2-Drying oven; 3-First temperature sensor; 4-Feed regulating valve; 5-Vacuum pump; 6-Air supply regulating valve; 7-Negative pressure gauge; 8-Third flow meter; 9-Second temperature sensor; 10-First flow meter; 11-Compressor; 12-Fourth temperature sensor; 13-Condensing device; 14-Second circulation pump; 15-Exhaust gas discharge port; 16-Waste liquid discharge port; 17-Water tank; 18-Roller conveyor; 19-Drying drum; 20-Rotating tray; 21-Heating coil; 22-Third temperature sensor; 23-First circulation pump; 24-Condenser; 25-Expansion valve; 26-Evaporator; 27-Fifth temperature sensor; 28-Second flow meter. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0028] In the description of the embodiments of this application, the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this application and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set up," "have," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] Example 1:

[0031] like Figure 1 As shown, a vacuum drying system for radioactive concentrate includes a drying chamber 2, a water-cooled heat pump unit, a condenser 13, a water tank 17, a waste discharge outlet, and a vacuum pump 5.

[0032] The drying box 2 is used to hold the radioactive concentrate and is equipped with a pull-out door 1.

[0033] The water-cooled heat pump unit includes a heating coil 21, a condenser 24, an expansion valve 25, an evaporator 26, and a compressor 11. The heating coil 21 is located inside the drying chamber 2 and heats the concentrated liquid inside the drying chamber 2 to dry it. The heating coil 21 has an inlet end and an outlet end. The outlet end of the heating coil 21 is connected to the inlet end A of the condenser 24, and the coolant outlet end B of the condenser 24 is connected to the inlet end of the heating coil 21. The outlet end C of the evaporator 26 is connected to the compressor 11, and the outlet end of the compressor 11 is connected to the inlet end D of the condenser 24. An expansion valve 25 is provided on the connecting pipe between the condenser 24 and the evaporator 26. The outlet end E of the evaporator 26 is connected to the condensing device 13, the outlet of the condensing device 13 is connected to the water tank 17, and the outlet of the water tank 17 is connected to the inlet end F of the evaporator 26.

[0034] In this embodiment of the invention, the condenser 24, expansion valve 25, evaporator 26, and compressor 11 work together to remove moisture from the concentrate by relying on the pressure difference between the concentrate and the air inside the drying chamber 2. This solves the problems of incomplete drying and excessive free water in conventional drying methods, enhancing the drying effect on radioactive concentrates. Simultaneously, a condenser 13 is connected to the outlet of the evaporator 26, and the condensed water is fed into a water tank 17. This allows the cooling energy generated at the evaporator 26 to be carried away sequentially by the condenser 13 and the water tank 17, increasing energy reuse and reducing energy loss.

[0035] A vacuum pump 5 is installed on the connecting pipe between the drying chamber 2 and the condensing device 13, and the waste discharge outlet is located at the waste outlet end of the condensing device 13. During use, the vacuum pump 5 can be used to adjust the air pressure inside the drying chamber 2, thereby combining with the water-cooled cooling unit to achieve the discharge of water from the concentrated liquid by relying on the pressure difference between the concentrated liquid and the air inside the drying chamber 2. Compared with existing drying methods such as electric heating drying and hot air drying, more importantly, the drying system of this embodiment has better drying effect, good uniformity, does not stick to the wall, and dries evenly.

[0036] Based on the above, the drying chamber 2 is equipped with a first temperature sensor 3, a feed regulating valve 4, an air inlet regulating valve, and a negative pressure gauge 7. The first temperature sensor 3 is used to monitor the temperature inside the drying chamber 2, the feed regulating valve 4 is used to regulate the amount of material fed into the drying barrel 19, the air inlet regulating valve is used to regulate the amount of air supplied to the vacuum chamber, and the negative pressure gauge 7 is used to monitor the negative pressure inside the vacuum chamber.

[0037] Building upon the above, further, a second temperature sensor 9 and a first flow meter 10 are installed on the connecting pipe between the outlet end of the heating coil 21 and the condenser 24, and a first circulation pump 23 and a third temperature sensor 22 are installed on the connecting pipe between the condenser 24 and the inlet end of the heating coil 21. The second temperature sensor 9 is used to monitor the temperature at the inlet end of the condenser 24, and the first flow meter 10 is used to monitor the water flow rate inside the condenser 24. The first circulation pump 23 is used to provide power for the circulating water at the condenser 24 end; the third temperature sensor 22 is used to monitor the temperature at the outlet end of the condenser 24.

[0038] Furthermore, a fourth temperature sensor 12 is installed on the connecting pipe between the evaporator 26 and the condenser 13 to monitor the temperature at the outlet of the evaporator 26. A second circulation pump 14 is installed on the connecting pipe between the condenser 13 and the water tank 17 to provide power for the circulating water at the evaporator 26. A second flow meter 28 and a fifth temperature sensor 27 are installed on the connecting pipe between the water tank 17 and the evaporator 26. The second flow meter 28 is used to monitor the water flow rate entering the evaporator 26, and the fifth temperature sensor 27 is used to monitor the temperature at the inlet of the evaporator 26.

[0039] A third flow meter 8 is installed on the connecting pipeline between the vacuum pump 5 and the condensation device 13 to monitor the flow rate of the waste gas generated after drying.

[0040] By arranging various thermometers, flow meters, etc., the temperature changes at each inlet and outlet end and the water flow changes in each inlet and outlet pipeline are monitored in real time, providing feedback for the control of the water-cooled heating unit and thus improving control efficiency.

[0041] Furthermore, the waste discharge outlets include a waste gas discharge outlet 15 and a waste liquid discharge outlet 16, both located at their respective outlets of the condensation device 13. The waste gas exiting the drying chamber 2 is condensed into a liquid state by the condensation device 13 and exits through the waste liquid discharge outlet 16, while the unconverted gas exits through the waste gas discharge outlet 15.

[0042] Example 2:

[0043] Based on Example 1, such as Figure 1 As shown, a drying tank 19 is provided inside the drying chamber 2. The drying tank 19 has an opening, allowing the radioactive concentrate to be placed inside. The amount of radioactive concentrate entering the drying tank 19 is controlled by the feed regulating valve 4. Furthermore, the drying tank 19 is in contact with the heating coil 21, utilizing the heat from the heating coil 21 to transfer heat to the drying tank 19, thereby drying the radioactive concentrate.

[0044] To achieve more uniform drying and better results, the heating coil 21 is arranged in a serpentine pattern, with the heating coil 21 being semi-circular in the radial direction. Viewed from above, the heating coil 21 appears as a semi-circular ring, with the inner diameter of the semicircle equal to the outer diameter of the drying drum 19. This allows the heating coil 21 to fit against the outside of the drying drum 19. The heating coil 21 is folded along half of the drying drum 19 to increase the heating area of ​​the drying drum 19, resulting in better uniform heating and enhanced drying effect.

[0045] Furthermore, the drying drum 19 is fixed on the rotating tray 20. A rotary motor is installed at the bottom of the rotating tray 20, and the power output shaft of the rotary motor is fixedly connected to the rotating tray 20. A roller conveyor 18 is provided inside the drying chamber 2, and the rotary motor is slidably engaged with the roller conveyor 18. In use, the drying drum 19 can be fixedly placed on the rotating tray 20 from the outside, and then fed into the drying chamber 2 as a whole along the roller conveyor 18, where it fits against the heating coil 21. The rotary motor is started, and the rotating tray 20 rotates, causing the drying drum 19 to rotate synchronously with it. Thus, by folding the heating coil 21 along half of the circumference of the drying drum 19, and combining this with the rotation of the rotating tray 20 to make the drying drum 19 rotate, the drying drum is heated evenly while increasing the heating area of ​​the standard drum, effectively enhancing the drying effect.

[0046] Furthermore, a pressure monitoring gauge is provided inside the rotating tray 20 to monitor the weight of the drying drum 19 and the material. The pressure monitoring gauge is a pressure sensor.

[0047] The specific operation method of the vacuum drying system in this embodiment of the invention is as follows:

[0048] 1) Open the stretching door 1, place the drying barrel 19 on the rotating tray 20, and send it into the drying chamber 2 along the roller conveyor 18 to the position where it is in contact with the heating coil 21;

[0049] 2) Close the pull-out door 1, turn on the vacuum pump 5, and adjust the air supply regulating valve 6 according to the data on the negative pressure gauge 7 to keep the negative pressure in the vacuum chamber within a suitable range.

[0050] 3) Turn on the second circulation pump 14 and the first circulation pump 23 to circulate the water on the corresponding pipes of the condenser 24 and the evaporator 26;

[0051] 4) Turn on compressor 11 and run it for a period of time. Then observe whether the parameters of the instruments on the condenser 24 and evaporator 26 meet the requirements.

[0052] 5) Open the feed regulating valve 4 and feed the radioactive concentrate into the drying tank 19. Each feed height is 10% of the body of the drying tank 19.

[0053] 6) After feeding is completed, close the feed regulating valve 4, the rotating tray 20 starts to rotate, and the weight of the radioactive concentrate in the drying tank 19 is monitored by the pressure sensor built into the rotating tray 20.

[0054] 7) The waste gas generated during the drying process is condensed by the condenser 13, and the moisture in the waste gas is discharged through the waste liquid discharge port 16. The condensed waste gas is discharged through the waste gas discharge port 15.

[0055] 8) After the data from the pressure sensor built into the rotating tray 20 does not change, open the feed regulating valve 4 again to feed the radioactive concentrate into the drying tank 19 until the dried product in the drying tank 19 reaches 80% of the tank body, and then stop the repeated feeding operation.

[0056] 9) Turn off the rotating equipment in sequence, including compressor 11, second circulation pump 14, first circulation pump 23, and vacuum pump 5;

[0057] 10) Open the pull-out door 1 and take out the drying drum 19;

[0058] 11) Close the sliding door 1 and turn off all power.

[0059] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vacuum drying system for radioactive concentrate, characterized in that, Includes a drying box (2), a water-cooled heat pump unit, a condensing device (13), a water tank (17), a waste discharge outlet, and a vacuum pump (5); The water-cooled heat pump unit includes a heating coil (21), a condenser (24), an expansion valve (25), an evaporator (26), and a compressor (11). The heating coil (21) is located inside the drying chamber (2). The outlet end of the heating coil (21) is connected to the coolant inlet end of the condenser (24), and the coolant outlet end of the condenser (24) is connected to the inlet end of the heating coil (21). The outlet end of the evaporator (26) is connected to the compressor (11), and the outlet end of the compressor (11) is connected to the evaporator (26). An expansion valve (25) is provided on the connecting pipe between the condenser (24) and the evaporator (26). The outlet of the evaporator (26) is connected to the condensing device (13). The outlet of the condensing device (13) is connected to the water tank (17). The outlet of the water tank (17) is connected to the inlet of the evaporator (26). A vacuum pump (5) is provided on the connecting pipe between the drying box (2) and the condensing device (13). The waste discharge outlet is located at the waste outlet end of the condensing device (13). The drying chamber (2) is equipped with a drying barrel (19), which has an opening for adding radioactive concentrate, and the drying barrel (19) is attached to the heating coil (21); The heating coil (21) is arranged in a serpentine pattern, and the heating coil (21) is semi-circular in the radial direction and fits against the outside of the drying barrel (19); The drying barrel (19) is fixed on the rotating tray (20), the bottom of the rotating tray (20) is provided with a rotating motor, and the drying box (2) is provided with a roller conveyor (18), the rotating motor and the roller conveyor (18) are in sliding cooperation.

2. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, The drying chamber (2) is equipped with a first temperature sensor (3), a feed regulating valve (4), an air inlet regulating valve, and a negative pressure gauge (7).

3. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, A second temperature sensor (9) and a first flow meter (10) are provided on the connecting pipe between the outlet end of the heating coil (21) and the condenser (24). A first circulation pump (23) and a third temperature sensor (22) are provided on the connecting pipe between the condenser (24) and the inlet end of the heating coil (21).

4. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, A fourth temperature sensor (12) is provided on the connecting pipe between the evaporator (26) and the condenser (13). A second circulation pump (14) is provided on the connecting pipe between the condenser (13) and the water tank (17). A second flow meter (28) and a fifth temperature sensor (27) are provided on the connecting pipe between the water tank (17) and the evaporator (26).

5. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, A third flow meter (8) is provided on the connecting pipeline between the vacuum pump (5) and the condenser (13).

6. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, The waste discharge outlets include a waste gas discharge outlet (15) and a waste liquid discharge outlet (16), both of which are located at the corresponding outlets of the condensation device (13).

7. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, The drying oven (2) is equipped with a pull-out door (1).

8. The vacuum drying system for radioactive concentrate according to claim 1, characterized in that, The rotating tray (20) is equipped with a pressure monitoring gauge.

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