A novel triple-effect evaporation device

Abstract

The utility model discloses a novel three-effect evaporator, and each effect evaporator is connected with each effect heater through forced circulation pump, secondary steam generated by the last effect evaporator enters the next effect heater, and the drainage of the last effect evaporator enters the next effect evaporator, and the steam generated by the last effect evaporator is connected with vacuum pump I through condenser and gas-liquid separator I, the shell side outlet of second effect heater and third effect heater is connected with one vacuumizing device respectively, and the vacuumizing device includes gas-liquid separator II, vacuum pump II and condensate tank II. When the water quality and water temperature change, the vacuum degree of each effect evaporator can be controlled separately and fine-tuned accurately, which greatly increases the adaptability of three-effect evaporator to sewage treatment and ensures the stable operation of the system. When vacuum pump II is running, there is only single medium in each pipeline, so the vacuum degree in the pipeline and evaporator can be kept stable, and the steam quantity generated by each effect evaporator is stable.

Description

Technical Field

[0001] This utility model belongs to the field of water treatment equipment, specifically relating to a novel triple-effect evaporation device. Background Technology

[0002] Triple-effect evaporation is a multi-effect evaporation and concentration process that uses three evaporators (effects) connected in series. The secondary steam generated in the previous effect is used as the heat source for the next effect, achieving cascaded utilization of thermal energy and significantly improving energy efficiency. Its core objective is to concentrate low-concentration solutions to target concentrations (such as for crystallization or pre-drying treatment), and it is widely used in industries such as chemical, pharmaceutical, and power generation.

[0003] like Figure 1 As shown, the operation process of a traditional triple-effect evaporator is as follows: Industrial wastewater to be treated enters the first-effect evaporator 21 via a wastewater booster pump. Under the action of a forced circulation pump 3, the wastewater passes through the tube side of the first-effect heater 11. High-temperature steam enters the shell side of the first-effect heater 11 via a regulating valve 105. The industrial wastewater and high-temperature steam exchange heat in the first-effect heater 11. After heat exchange in the first-effect heater 11, the industrial wastewater reaches the design temperature and enters the first-effect evaporator 21 for evaporation and volume reduction treatment. The steam generated in the first-effect evaporator 21 enters the second-effect heater 1... 2. The drainage water after evaporation in the first-effect evaporator 21 (also called the first-effect evaporator drainage) enters the second-effect evaporator 22, and is heated by the forced circulation pump 3 into the second-effect heater 12. The heated first-effect evaporator drainage then enters the second-effect evaporator 22 for evaporation reduction treatment. The steam generated in the second-effect evaporator 22 enters the third-effect heater 13 to heat the second-effect evaporator drainage. The heated second-effect evaporator drainage then enters the third-effect evaporator 23 for evaporation reduction treatment. The steam generated in the third-effect evaporator enters the condenser 6, and the condensate is discharged to the condensate tank I. 71. The condensate tank Ⅰ 71 is connected to the vacuum pump Ⅰ 51 through the gas-liquid separator Ⅰ 41, so that a vacuum negative pressure state is formed in the third-effect evaporator 23; the first-effect evaporator 21 and the second-effect evaporator 22 are connected in series through pipes. The series connection means that the tube-side outlet of the second-effect heater 12 and the tube-side outlet of the third-effect heater 13 are connected to the condensate tank Ⅰ 71 through a pipe, and then connected to the vacuum pump Ⅰ 51 through the gas-liquid separator Ⅰ 41, so that the condensate tank Ⅰ 71 and each effect evaporator 2 are in a vacuum state.

[0004] Because the pipes connecting the outlet of the second-effect heater 12 and the outlet of the third-effect heater 13 to the condensate tank I 71 contain a mixture of liquid and air, the vacuum level in each evaporator is unstable. This unstable vacuum level leads to unstable steam production in each evaporator and unstable wastewater evaporation, resulting in the final concentration of organic wastewater failing to meet expectations, exceeding expectations, or even causing scaling. In addition, the first-effect evaporator 21 and the second-effect evaporator 22 are condensed by the steam from the second-effect heater 12 and the third-effect heater 13, respectively, and are connected in series through pipes. They are discharged together with the condensate produced by the condenser of the third-effect evaporator to the condensate tank I 71. Finally, after gas-liquid separation, a vacuum is drawn. Since the vacuum degree in each evaporator is achieved by the vacuum pump I 51, the vacuum degree in each evaporator cannot be independently and accurately adjusted and controlled. When the water quality, water temperature and other factors of the industrial wastewater to be treated fluctuate greatly, the existing three-effect evaporation device cannot adjust the parameters of each evaporator individually, in a timely manner and accurately. It cannot adapt to the treatment of the incoming water, resulting in insufficient system output or scaling and inability to operate the system. Summary of the Invention

[0005] To address the problem of poor adaptability of existing triple-effect evaporators to industrial wastewater treatment, this invention provides a novel triple-effect evaporator.

[0006] The purpose of this utility model is achieved in the following manner: A novel triple-effect evaporation device includes three evaporators connected in sequence. Each evaporator is connected to a heater via a forced circulation pump. Secondary steam generated by the previous evaporator enters the next heater, and the evaporated wastewater enters the next evaporator. Steam generated by the last evaporator is condensed by a condenser and enters a condensate tank I. The condensate tank I is connected to a vacuum pump I via a gas-liquid separator I. Flow meters and thermometers are installed on the pipes between the previous evaporator and the next heater. Level gauges and pressure sensors are installed on each evaporator. The condensate from the second and third heaters is connected to a vacuum device via pipes. The vacuum device includes a gas-liquid separator II. The gas outlet of the gas-liquid separator II is connected to the vacuum pump II, and the liquid outlet is connected to the condensate tank II.

[0007] Condensate tank II is connected to vacuum pump III via gas-liquid separator III.

[0008] Steam supply valves are installed on the pipes between the first-effect evaporator and the second-effect heater, and on the pipes between the second-effect evaporator and the third-effect heater. The steam supply valves are also connected to the steam source via Venturi injectors. Flow meters and thermometers are installed on the steam supply pipes between the steam source and the heater.

[0009] A steam discharge valve is installed on the pipe between the second-effect evaporator and the third-effect heater, and a flow meter is installed on the steam discharge pipe downstream of the steam discharge valve.

[0010] Compared to existing technologies, the second-effect heater and the third-effect heater are each connected to an independent vacuum pump. When the quality and temperature of the incoming water change, the vacuum level of each evaporator can be controlled and precisely adjusted individually, greatly increasing the adaptability of the three-effect evaporator to wastewater treatment and ensuring the stable operation of the system. When vacuum pump II is running, there is only a single medium in each pipeline, so the vacuum level in the pipeline and evaporator can be kept stable, and the amount of steam generated by each evaporator is stable. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a triple-effect evaporator in the prior art.

[0012] Figure 2 This is a schematic diagram of the triple-effect evaporation device of this utility model.

[0013] In the diagram: Heater 1, First-effect heater 11, Second-effect heater 12, Third-effect heater 13, Evaporator 2, First-effect evaporator 21, Second-effect evaporator 22, Third-effect evaporator 23, Forced circulation pump 3, Gas-liquid separator I 41, First gas-liquid separator II 42, First gas-liquid separator III 43, Second gas-liquid separator II 44, Second gas-liquid separator III 45, Vacuum pump I 51, First vacuum pump II 52, First vacuum pump III 53, Second vacuum pump II 54, Second vacuum pump III 55, Condenser 6, Condensate tank I 71, First condensate tank II 72, Second condensate tank II 73, Level gauge 8, Flow meter 9, Thermometer 10, Pressure sensor 101, Steam supply valve 102, Steam discharge valve 104, Adjustment valve 105. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention. After reading the contents of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the present invention.

[0015] like Figure 2As shown, this utility model discloses a novel triple-effect evaporator device, comprising three evaporators 2 connected in sequence. Each evaporator 2 is connected to a heater 1 via a forced circulation pump 3. Secondary steam generated by the previous evaporator enters the next heater, and the evaporated wastewater enters the next evaporator. Steam generated by the last evaporator is condensed by a condenser 6 and enters a condensate tank I 71. The condensate tank I 71 is connected to a vacuum pump I 51 via a gas-liquid separator I 41. Flow meters 9 and thermometers 10 are installed on the pipes between the previous evaporator and the next heater. Each evaporator is equipped with a level gauge 8 and a pressure sensor 101. The condensate from the second heater 12 and the third heater 13 is respectively connected to a vacuum device. The vacuum device connected to the shell-side outlet of the second heater 12 includes a first gas-liquid separator II 42. The gas outlet of the first gas-liquid separator II is connected to the first vacuum pump II 52, and the liquid outlet is connected to the first condensate tank II 72. The vacuum device connected to the shell-side outlet of the third heater 13 includes a second gas-liquid separator II 42. 44. The gas outlet of the second gas-liquid separator II 44 is connected to the second vacuum pump II 54, and the liquid outlet is connected to the second condensate tank II 73.

[0016] The operation process of a novel triple-effect evaporator device disclosed in this utility model is as follows: The industrial wastewater to be treated enters the first-effect evaporator 21 via a wastewater lift pump. Under the action of the forced circulation pump 3, the wastewater passes through the tube side of the first-effect heater 11. High-temperature steam enters the shell side of the first-effect heater 11 via the regulating valve 105. The industrial wastewater and high-temperature steam exchange heat in the first-effect heater 11. The heated industrial wastewater then enters the first-effect evaporator 21 for volume reduction evaporation treatment. The steam generated in the first-effect evaporator 21 enters the shell side of the second-effect heater 12. The wastewater from the first-effect evaporator 21 flows into the second-effect evaporator 22. Under the action of the forced circulation pump 3, the wastewater in the second-effect evaporator 22 enters the tube side of the second-effect heater 12 and exchanges heat with the steam in the shell side. The heated industrial wastewater then enters the second-effect evaporator 22 for volume reduction evaporation treatment. The steam generated in the first-effect evaporator 21 enters the shell side of the second-effect heater 12 and exchanges heat with the wastewater in the tube side. The steam cools and becomes condensate in the shell side, then passes through the first gas-liquid separator II 42. The separated water exits from the first gas-liquid separator II. The bottom of the first gas-liquid separator II 42 is discharged into the first condensate tank II 72. The top of the first gas-liquid separator II 42 is connected to the first vacuum pump II 52. The steam generated by the second-effect evaporator enters the shell side of the third-effect heater 13, and the wastewater from the second-effect evaporator 22 enters the third-effect evaporator 23. The wastewater in the third-effect evaporator 23 enters the tube side of the third-effect heater 13 under the action of the forced circulation pump 3, where it exchanges heat with the steam in the shell side and is heated. The heated industrial wastewater then enters the third-effect evaporator 23 to begin evaporation and volume reduction treatment. The steam generated by the second-effect evaporator 22 enters the shell side of the third-effect heater 13 and exchanges heat with the wastewater in the tube side of the third-effect heater 13. The steam is cooled and becomes condensate in the shell side, and then passes through the second gas-liquid separator II 44. The separated water is discharged from the bottom of the second gas-liquid separator II 44 into the second condensate tank II 73. The top of the second gas-liquid separator II 44 is connected to the second vacuum pump II 54. The steam generated by the third-effect evaporator 23 enters the condenser 6, and the condensate is discharged into the condensate tank I. 71. The condensate tank Ⅰ 71 is connected to the vacuum pump Ⅰ 51 through the gas-liquid separator Ⅰ 41, so that a vacuum negative pressure state is formed in each effect evaporator.

[0017] The second-effect heater 12 and the third-effect heater 13 are each connected to a vacuum device, allowing the vacuum levels of the first-effect evaporator 21 and the second-effect evaporator 22 to be individually controlled and precisely adjusted. This greatly increases the adaptability of the three-effect evaporator to wastewater treatment and ensures stable system operation. After the steam passes through the heat exchanger in the heater shell side, the water vapor condenses to form water. The condensate and non-condensable gas-water mixture are separated by the first gas-liquid separator II 42. When the first vacuum pump II 52 is running, only a single medium (water or gas) exists in the pipeline, thus maintaining a stable vacuum level in the pipeline and in the second-effect evaporator. Similarly, the vacuum level in the third-effect evaporator remains stable, and the vacuum level of the third small evaporator is also individually controlled and maintained stably. This ensures a stable steam output from each evaporator and a stable wastewater evaporation rate, ultimately achieving the expected concentration of organic wastewater and preventing scaling.

[0018] Furthermore, the first condensate tank II 72 is connected to the first vacuum pump III 53 via the first gas-liquid separator III 43. The second condensate tank II 73 is connected to the second vacuum pump III 55 via the second gas-liquid separator III 45. The first vacuum pump III 53 and the second vacuum pump III 55 are redundantly designed.

[0019] Because the pressures of each effect evaporator in a triple-effect evaporator are preset, large-scale pressure adjustments can cause a series of chain reactions in the operation of the three evaporators, making system stability difficult to control. Therefore, the vacuum devices connected to the shell-side outlets of the second-effect heater 12 and the third-effect heater 13 are mainly used for fine-tuning the pressures of the first-effect evaporator 21 and the second-effect evaporator 22, and for maintaining pressure stability within these evaporators. In addition to pressure, the steam flow rate also affects the evaporation rate of each effect evaporator. Directly adjusting the steam flow rate entering the first-effect heater can easily cause a series of chain reactions in the operation of the three evaporators, making system stability difficult to control. Adjusting the steam flow rate of the second and third-effect evaporators separately is more convenient and provides better system stability.

[0020] Steam supply valves 102 are installed on the pipes between the first-effect evaporator 21 and the second-effect heater 12, and on the pipes between the second-effect evaporator 22 and the third-effect heater 13. The steam supply valves 102 are also connected to the steam source through the Venturi injector 103. A flow meter 9 and a thermometer 10 are installed on the steam supply pipes between the steam source and 102.

[0021] When the content of suspended solids and non-scaling salts in industrial wastewater increases, the evaporation of wastewater becomes more difficult due to the strong hygroscopic properties of these substances. Alternatively, if the water temperature drops significantly (e.g., by 10°C), the steam output of the first-effect evaporator 21, operating according to the original design parameters, may be insufficient to meet the changing wastewater volume. In this case, high-temperature steam is supplemented through the Venturi ejector 103, entering the shell side of the second-effect heater 12 along with the steam generated by the first-effect evaporator 21. This provides sufficient heat to raise the temperature of the water delivered by the forced circulation pump 3 to the required level. Similarly, high-temperature steam is supplemented through the Venturi ejector 103 in the pipeline between the second-effect evaporator 22 and the third-effect heater 13, entering the third-effect evaporator 13 along with the steam generated by the second-effect evaporator 22. This increases the temperature rise of the circulating water delivered by the forced circulation pump 3, ensuring that the wastewater reduction evaporation treatment in the third-effect evaporator 23 achieves the planned treatment effect and reduction ratio. Depending on the incoming water quality, it may be necessary to supplement high-temperature steam at the front end of the second-effect heater, the front end of the third-effect heater, or simultaneously at the front ends of both the second-effect and third-effect heaters to ensure the normal operation of the wastewater reduction evaporation treatment in the second-effect evaporator 22 and the third-effect evaporator 23. The set difference of the inlet and outlet thermometers of the second-effect heater 12 or the third-effect heater 13 can be interlocked with 102 to control the input amount of supplementary steam.

[0022] In a further preferred embodiment, a steam discharge valve 104 is installed on the pipe between the second-effect evaporator 22 and the third-effect heater 13, and a flow meter 9 is installed on the steam discharge pipe at the rear end of the steam discharge valve.

[0023] When the quality of industrial wastewater changes, manifested as a significant increase in the content of easily scale-forming substances such as salts, and the third-effect evaporator 23 is at risk of scaling under the original reduced-volume evaporation process parameters, the steam discharge valve 14 is opened to reduce the amount of steam entering the shell-side inlet of the third-effect heater 13. This reduces the evaporation rate of the third-effect evaporator 23, lowers the reduction-volume concentration ratio, prevents equipment scaling, and ensures normal equipment operation. The temperature difference settings of the inlet and outlet thermometers of the third-effect heater 13 can be interlocked with the steam discharge valve 14 to control the amount of steam discharged.

[0024] The above description is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present utility model, and these should also be considered within the protection scope of the present utility model.

Claims

1. A novel triple-effect evaporator, comprising three evaporators (2) connected in sequence, each evaporator (2) being connected to a heater (1) of each effect via a forced circulation pump (3), the secondary steam generated by the previous evaporator entering the heater of the next effect, the evaporated wastewater entering the next evaporator, the steam generated by the last evaporator (23) being condensed by a condenser (6) and entering a condensate tank I (71), the condensate tank I (71) being connected to a vacuum pump I (51) via a gas-liquid separator I (41), a flow meter (9) and a thermometer (10) being installed on the pipes between the previous evaporator and the heater of the next effect, and a level gauge (8) and a pressure sensor (101) being installed on each evaporator, characterized in that: The condensate of the second-effect heater (12) and the third-effect heater (13) are respectively connected to a vacuum device. The vacuum device includes a gas-liquid separator II (42 / 44), the gas outlet of the gas-liquid separator II is connected to a vacuum pump II (52 / 54), and the liquid outlet is connected to a condensate tank II (72 / 73).

2. The novel triple-effect evaporator according to claim 1, characterized in that: Condensate tank II is connected to vacuum pump III via gas-liquid separator III.

3. The novel triple-effect evaporator according to claim 1, characterized in that: Steam supply valves (102) are installed on the pipe between the first-effect evaporator (21) and the second-effect heater (12), and on the pipe between the second-effect evaporator (22) and the third-effect heater (13). The steam supply valves (102) are also connected to the steam source through the Venturi injector (103). A flow meter (9) and a thermometer (10) are installed on the steam supply pipe between the steam source and (102).

4. The novel triple-effect evaporator according to claim 1 or 3, characterized in that: A steam discharge valve (104) is installed on the pipe between the second-effect evaporator (22) and the third-effect heater (13), and a flow meter (9) is installed on the steam discharge pipe at the rear end of the steam discharge valve.

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