Desulfurization slurry waste heat recovery system

Abstract

The utility model belongs to the technical field of waste heat recovery, and particularly relates to a desulfurization slurry waste heat recovery system which comprises a flash evaporation module, a heat pump module and a pressure increasing module, the input end of the flash evaporation module is connected with a liquid conveying pipeline, and the flash evaporation module is connected with the pressure increasing module through a first steam exhaust pipeline. The pressure increasing module is communicated with the heat pump module through a second dead steam pipeline, the heat pump module is provided with a driving steam inlet and a dead steam condensate water outlet, the driving steam inlet is connected with a driving steam pipeline, the driving steam pipeline is provided with a driving steam adjusting valve, and the dead steam condensate water outlet is connected with a dead steam condensate water pipeline. The dead steam condensate pipeline is connected with the condensate tank and the water quality detection sensor, and the dead steam pipeline I is provided with a pressure sensor and a temperature sensor. The heat exchange efficiency of the system is improved; and the corrosive liquid entering the heat pump module along with the steam is reduced.

Description

Technical Field

[0001] This utility model relates to a waste heat recovery system for desulfurization slurry, belonging to the field of waste heat recovery technology. Background Technology

[0002] In wet flue gas desulfurization (FGD) systems in power plants, the desulfurization slurry contains a large amount of low-temperature waste heat. Due to its relatively low temperature and unsuitable medium composition, the earliest utilization methods were direct spraying or indirect heat exchange, which resulted in water pollution or low heat exchange efficiency. In recent years, universities and enterprises have begun to utilize desulfurization slurry for flash evaporation and heat extraction for heating. Recovering waste heat from desulfurization slurry for heating can replace some of the steam extracted from power plant turbines, reducing high-pressure steam consumption and contributing to energy conservation and emission reduction. Furthermore, the condensate from the flash evaporation, provided water quality is maintained, can be used for heating network makeup water and process water, which is particularly important in water-scarce regions. However, several problems remain. For example, depending on the composition of the desulfurization slurry during actual operation, non-condensable gases may be generated, affecting heat pump operation and hindering waste heat recovery. Additionally, the quality of the flash evaporation waste steam fluctuates, and during flash evaporation, liquid boiling can cause flash steam to carry corrosive liquids, posing a risk of corrosion to heat pump equipment and affecting condensate quality. Therefore, there is a need for a desulfurization slurry waste heat recovery system that reduces the entry of corrosive liquids into the waste heat recovery system pipelines and can promptly discharge non-condensable vapors from the system. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a desulfurization slurry waste heat recovery system.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0005] A desulfurization slurry waste heat recovery system includes a flash evaporation module, a heat pump module, and a pressurization module. The input end of the flash evaporation module is connected to the liquid transport pipeline of the desulfurization slurry. The flash evaporation module and the pressurization module are connected through a first waste steam pipeline, and the pressurization module and the heat pump module are connected through a second waste steam pipeline. The flash evaporation module is used to flash evaporate water in the desulfurization slurry to obtain low-temperature, low-pressure steam by means of flash vaporization. The pressurization module is used to compress and raise the temperature of the low-temperature, low-pressure steam obtained by the flash evaporation module to obtain high-temperature, high-pressure steam.

[0006] The heat pump module is equipped with a driving steam inlet and a waste steam condensate outlet. The driving steam inlet is connected to an internal generator and a driving steam pipe is connected to it. A driving steam regulating valve is provided on the driving steam pipe.

[0007] The exhaust steam condensate outlet is connected to an exhaust steam condensate pipe, which is connected to a condensate tank. The condensate tank is equipped with a condensate drain valve and a water supply valve. A water quality detection sensor is installed on the exhaust steam condensate pipe. A pressure sensor and a temperature sensor are installed on the exhaust steam pipe. An air extraction pipe is installed on the exhaust steam pipe, and an air extraction electric control valve is installed on the air extraction pipe.

[0008] The beneficial effects of this utility model are as follows: By installing pressure and temperature sensors on the first waste steam pipeline, the temperature and pressure of the flashed waste steam in the first waste steam pipeline are detected. Based on the saturation temperature and saturated vapor pressure of the gas, it is determined whether the flashed waste steam contains too much non-condensable vapor. If non-condensable vapor occupies the heat exchange space for a long time, under the condition that other operating conditions remain unchanged, it will manifest as high pressure in the pipeline. By detecting the pressure in the first waste steam pipeline, the amount of non-condensable vapor can be roughly determined. If the pressure is detected to be too high, it means that the amount of non-condensable vapor has affected the heat exchange efficiency. Then, the extraction valve is activated, the extraction pipeline is opened, and the non-condensable vapor is discharged from the system, so as to avoid the non-condensable vapor occupying the heat exchange area of ​​the heat pump module, affecting the operation of the heat pump, and improving the heat exchange efficiency of the system.

[0009] This invention utilizes a water quality sensor. When the sensor detects normal water quality in the exhaust steam condensate, the water supply valve opens and the condensate drain valve closes, supplying condensate to the external system. When the sensor detects abnormal water quality (i.e., the presence of corrosive substances), the water supply valve closes and the condensate drain valve opens, draining water from the condensate tank to prevent it from entering the water supply system and corroding equipment. Simultaneously, by controlling the opening of the heat pump module's drive steam regulating valve, the flash evaporation rate within the flash evaporation module is controlled. Specifically, reducing the drive steam supplied to the heat pump module reduces the amount of refrigerant emitted from the generator, lowering the overall operating efficiency of the heat pump module. This reduces the heat pump module's heat recovery capacity, consequently reducing its condensation capacity for gaseous exhaust steam. More exhaust steam remains gaseous, increasing the pressure within the exhaust steam pipeline. This increased pressure leads to a higher flash evaporation temperature, thereby reducing the flash evaporation rate within the flash evaporation module and minimizing the risk of corrosive liquid entering the heat pump module with the steam due to vigorous boiling in the flash tank. This effectively controls the condensate quality.

[0010] Based on the above technical solution, the present invention can be further improved as follows:

[0011] Furthermore, the high-pressure output terminal of the pressure boosting module is connected to the evaporator inside the heat pump module, and the driving steam inlet is connected to an external steam source; the absorber and condenser of the heat pump module are connected to an external heating network to achieve heating.

[0012] Furthermore, the high-pressure output end of the pressure boosting module is connected to the generator inside the heat pump module via the driving steam pipe, and the absorber and condenser of the heat pump module are connected to external cooling water; the evaporator of the heat pump module is connected to the external cooling network to achieve refrigeration.

[0013] Furthermore, it also includes a control module, which is connected to the drive steam regulating valve, pressure sensor, temperature sensor, air extraction electric control valve, water quality detection sensor, water supply valve, and condensate discharge valve respectively.

[0014] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The control module can control the drive steam regulating valve, the exhaust solenoid valve, and the drain solenoid valve in real time based on the detection results of the pressure sensor, temperature sensor, and water quality detection sensor. This allows for more accurate control of the amount of drive steam entering, the discharge of non-condensable steam, and the discharge of corrosive liquids. When the water quality is found to be substandard, it indicates that the flashed water carries corrosive liquids, meaning that the flashing is too intense. By controlling and adjusting the opening of the drive steam regulating valve, the pressure inside the flash tank can be adjusted in the opposite direction to reduce the degree of flashing, avoid an overly intense flashing process, and reduce the situation where the flashed water vapor carries corrosive liquids.

[0015] Furthermore, the air extraction pipe is provided with multiple pipes.

[0016] The beneficial effect of adopting the above-mentioned further technical solution is that non-condensable steam is discharged through multiple extraction pipes, thereby improving the efficiency of non-condensable steam discharge.

[0017] Furthermore, the extraction pipe is connected to a non-condensable steam collection tank. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the connection structure of the heat pump module in Embodiment 1 of this utility model;

[0020] Figure 3 This is a schematic diagram of the connection structure of the heat pump module in Embodiment 2 of this utility model.

[0021] The attached diagram is labeled as follows: 1. Flash evaporation module; 2. Heat pump module; 3. Drive steam regulating valve; 4. Liquid delivery pipeline; 5. Exhaust steam pipeline one; 6. Exhaust steam condensate pipeline; 7. Drive steam pipeline; 8. Pressure sensor; 9. Temperature sensor; 10. Extraction pipeline; 11. Extraction electric control valve; 12. Water quality detection sensor; 13. Pressure boosting module; 14. Exhaust steam pipeline two; 15. Non-condensable steam collection tank; 16. Condensate tank; 17. Make-up water supply valve; 18. Condensate discharge valve. Detailed Implementation

[0022] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0023] Example 1: (Heating Mode)

[0024] See Figure 1 A desulfurization slurry waste heat recovery system includes a flash evaporation module 1, a heat pump module 2, and a pressurization module 13. The input end of the flash evaporation module 1 is connected to a liquid conveying pipeline 4 for conveying the desulfurization slurry. The flash evaporation module 1 and the pressurization module 13 are connected via a waste steam pipeline 5, and the pressurization module 13 and the heat pump module 2 are connected via a waste steam pipeline 14. (See also...) Figure 2 An external steam heat source is connected to the generator inside the heat pump module 2 via a driving steam regulating valve 3 and a driving steam pipe 7. The exhaust steam pipe 14 connects to the evaporator inside the heat pump module 2. The gaseous exhaust steam condenses into water after heat exchange in the evaporator and is discharged from the heat pump module 2 via the exhaust steam condensate pipe 6. The absorber and condenser of the heat pump module 2 are connected to an external hot water supply network to provide external heating. In this example, the minimum temperature of flash steam at 20°C can be utilized. After the pressure and temperature are increased by the pressure boosting module, the temperature can be raised to 35°C. The heat from the exhaust steam is recovered through the heat pump module 2 for heating, and hot water above 95°C can be produced.

[0025] refer to Figure 1 The exhaust steam condensate pipe 6 is equipped with a water quality sensor 12. After the water quality sensor 12, a condensate tank 16 is located. The condensate tank 16 is equipped with a condensate drain valve 18 and a water supply valve 17. When the water quality sensor 12 detects that the exhaust steam condensate water quality is normal, the water supply valve 17 opens and the condensate drain valve 18 closes, supplying condensate water to the external system. When the water quality sensor 12 detects that the exhaust steam condensate water quality is abnormal (i.e., carrying corrosive substances), the water supply valve 17 closes and the condensate drain valve 18 opens, draining the water from the condensate tank 16 to prevent it from entering the water supply system and corroding equipment. Simultaneously, the heat pump is controlled... The opening degree of the driving steam regulating valve 3 of module 2 controls the flash evaporation amount in flash evaporation module 1. Specifically, it reduces the driving steam supplied to heat pump module 2, thereby reducing the amount of refrigerant emitted from the generator, reducing the overall operating efficiency of heat pump module 2, reducing the heat recovery capacity of heat pump module 2, and consequently reducing the condensation capacity of heat pump module 2 for gaseous exhaust steam. More exhaust steam will remain in a gaseous state, which will increase the pressure in exhaust steam pipeline 5. The increased pressure and flash evaporation temperature will increase, thereby reducing the flash evaporation amount in flash evaporation module 1 and reducing the amount of corrosive liquid entering heat pump module 2 with the steam due to violent boiling in the flash tank, thus achieving the effect of controlling the quality of condensate.

[0026] The exhaust steam pipe 5 is equipped with a pressure sensor 8 and a temperature sensor 9. The exhaust steam pipe 5 is connected to an extraction pipe 10, which is equipped with an extraction solenoid valve 11. By using the pressure sensor 8 and temperature sensor 9 on the exhaust steam pipe 5 to detect the temperature and pressure of the flashed exhaust steam, the system can determine whether the flashed exhaust steam contains excessive non-condensable vapors based on the saturation temperature and saturated vapor pressure of the gas. If non-condensable vapors occupy the heat exchange space for a long time, under unchanged operating conditions, it will manifest as a higher pressure inside the pipe. By detecting the pressure inside the exhaust steam pipe 5, the amount of non-condensable vapors can be roughly determined. If a higher pressure is detected (a reasonable threshold can be set based on actual operating conditions), it means that the amount of non-condensable vapors has affected the heat exchange efficiency. In this case, the extraction pipe 10 is opened to discharge the non-condensable vapors from the system, preventing them from encroaching on the heat exchange area of ​​the heat pump module and affecting the operation of the heat pump module 2, thereby improving the system's heat exchange efficiency. Because non-condensable vapors may be corrosive, they need to be collected in a non-condensable vapor collection tank for further treatment before being discharged to avoid environmental pollution.

[0027] It also includes a control module (not shown in the figure), which is connected to the driving steam regulating valve 3, pressure sensor 8, temperature sensor 9, vacuum control valve 11, water quality detection sensor 12, water supply valve 17, and condensate discharge valve 18 to automatically implement the above control logic. This utility model does not limit the control module; specifically, in this embodiment, the control module is a PLC control system.

[0028] Example 2: (Cooling Mode)

[0029] Unlike Example 1, in this example, the connection relationship between heat pump module 2 and exhaust steam pipe 2 14 is as follows: Figure 3 As shown, exhaust steam pipe 2 14 is connected to the generator inside heat pump module 2 via drive steam regulating valve 3 and drive steam pipe 7. The gaseous exhaust steam condenses into liquid in the generator and is discharged from heat pump module 2 through exhaust steam condensate pipe 6. The evaporator of heat pump module 2 is connected to the external cooling water network; the absorber and condenser of heat pump module 2 are connected to the external cooling water network. In this scheme, refrigeration can be achieved by recovering and utilizing the waste heat of exhaust steam. The working principle of other positions is the same as in embodiment 1, and will not be described again here.

[0030] In this example, the exhaust steam is pressurized and heated to about 80°C by the pressurization device, which can be used as the driving heat source for the heat pump module. At the same time, the heat pump module is equipped with a cold water evaporator to realize the cooling function.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A waste heat recovery system for desulfurization slurry, characterized in that, The system includes a flash evaporation module (1), a heat pump module (2), and a pressure boosting module (13). The input end of the flash evaporation module (1) is connected to a liquid delivery pipeline (4). The flash evaporation module (1) and the pressure boosting module (13) are connected through a first exhaust steam pipeline (5). The pressure boosting module (13) and the heat pump module (2) are connected through a second exhaust steam pipeline (14). The flash evaporation module (1) is used to obtain low-temperature, low-pressure steam by means of the flash evaporation principle. The pressure boosting module (13) is used to compress and raise the temperature of the low-temperature, low-pressure steam obtained by the flash evaporation module (1) to obtain high-temperature, high-pressure steam. The heat pump module (2) is provided with a driving steam inlet and a waste steam condensate outlet. The driving steam inlet is connected to the internal generator. The driving steam inlet is connected to a driving steam pipe (7). The driving steam pipe (7) is provided with a driving steam regulating valve (3). The exhaust steam condensate outlet is connected to an exhaust steam condensate pipe (6), the exhaust steam condensate pipe (6) is equipped with a water quality detection sensor (12), the exhaust steam condensate pipe (6) is connected to a condensate tank (16), the condensate tank (16) is equipped with a condensate discharge valve (18) and a water supply valve (17); the exhaust steam pipe (5) is equipped with a pressure sensor (8) and a temperature sensor (9), the exhaust steam pipe (5) is equipped with an exhaust pipe (10), and the exhaust pipe (10) is equipped with an exhaust electric control valve (11).

2. The desulfurization slurry waste heat recovery system according to claim 1, characterized in that, The output end of the pressure boosting module (13) is connected to the evaporator in the heat pump module (2), and the driving steam inlet is connected to an external steam source; the absorber and condenser of the heat pump module (2) are connected to an external heating network to achieve heating.

3. The desulfurization slurry waste heat recovery system according to claim 1, characterized in that, The output end of the pressure boosting module (13) is connected to the generator in the heat pump module (2) via the driving steam pipe (7). The absorber and condenser of the heat pump module (2) are connected to external cooling water. The evaporator of the heat pump module (2) is connected to the external cooling network to achieve refrigeration.

4. The desulfurization slurry waste heat recovery system according to any one of claims 1-3, characterized in that, It also includes a control module, which is connected to the drive steam regulating valve (3), pressure sensor (8), temperature sensor (9), air extraction electric control valve (11), water quality detection sensor (12), water supply valve (17), and condensate discharge valve (18) respectively.

5. The desulfurization slurry waste heat recovery system according to claim 1, characterized in that, The air extraction pipe (10) is provided with multiple pipes.

6. The desulfurization slurry waste heat recovery system according to claim 1, characterized in that, The extraction pipe (10) is connected to the non-condensable steam collection tank (15).

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