Coal gas preheater flushing system and flushing method

Abstract

The present application belongs to the technical field of coke oven gas purification, and discloses a coal gas preheater flushing system and a flushing method. The coal gas preheater flushing system is used for flushing impurities on the internal tube bundle of the coal gas preheater, and comprises the coal gas preheater, an ammonia water flushing module and an impurity treatment module. The ammonia water flushing module comprises an ammonia evaporation tower, a splitter and a first valve, the splitter is arranged at the top of the ammonia evaporation tower, the remaining ammonia water outlet of the splitter is communicated with the upper cavity of the coal gas preheater, and the first valve is arranged downstream of the remaining ammonia water outlet; the impurity treatment module comprises an acid tar tank and a second valve, the acid tar tank is connected to the bottom of the coal gas preheater and communicated with the lower cavity, and the second valve is arranged upstream of the acid tar tank. The coal gas preheater flushing system can clean the coal gas preheater on line, has good cleaning effect, short cleaning time, and is beneficial to improving the production efficiency.

Description

Technical Field

[0001] This invention relates to the field of coke oven gas purification technology, and in particular to a gas preheater flushing system and flushing method. Background Technology

[0002] The coke oven gas purification process includes multiple steps such as condensation blasting, electrostatic precipitator for tar removal, and desulfurization. The purified coke oven gas then enters the ammonium sulfate section for ammonia removal. During ammonia removal, the coke oven gas from the blast condensation step enters a saturator. Since the saturator contains sulfuric acid mother liquor, the coke oven gas is washed by spraying sulfuric acid. The sulfuric acid reacts with the ammonia in the gas to form ammonium sulfate. However, to prevent moisture in the coke oven gas from entering the saturator before contacting sulfuric acid, diluting the mother liquor, disrupting the water balance within the saturator, and affecting the ammonia washing effect, the coke oven gas needs to undergo drying and dehydration treatment before entering the saturator. Existing drying and dehydration devices involve drying the coke oven gas from the blast condensation step through a gas preheater.

[0003] However, during the operation of the gas preheater, impurities such as tar in the gas adhere to the preheater tube bundle. After intermittent steam heating, these impurities harden and clog the tube bundle, increasing the preheater resistance and affecting the normal operation of the gas blower. When the gas preheater resistance becomes too high, operators are forced to shut down the original operating system, switch the preheater and saturator, and perform offline maintenance and cleaning. During disassembly and removal of the gas preheater, ferrous sulfide adhering to the tube wall is prone to spontaneous combustion upon contact with air, increasing the risk of gas poisoning, gas explosions, and other safety accidents. Furthermore, the entire preheater cleaning and maintenance process is lengthy, labor-intensive, and severely impacts work efficiency. Summary of the Invention

[0004] One objective of this invention is to provide a gas preheater flushing system that can clean the gas preheater online with good cleaning effect and short cleaning time, which is beneficial to improving production efficiency.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A gas preheater flushing system is used to flush impurities from the internal tube bundle of a gas preheater. The gas preheater includes a shell, an upper sealing plate, a lower sealing plate, and a heat exchange tube bundle. The upper and lower sealing plates are spaced apart within the shell, dividing the shell's interior into an upper cavity, a heat exchange cavity, and a lower cavity. The heat exchange tube bundle connects the upper and lower sealing plates and communicates with the upper and lower cavities. The top of the shell has a gas outlet communicating with the upper cavity, and the bottom of the shell has a gas inlet communicating with the lower cavity. A steam inlet and a steam outlet, respectively communicating with the heat exchange cavity, are located on the side of the shell. The steam inlet is located above the steam outlet. The gas preheater flushing system also includes:

[0007] The ammonia flushing module includes an ammonia stripping tower, a separator, and a first valve. The separator is located at the top of the ammonia stripping tower, and the residual ammonia outlet of the separator is connected to the upper cavity of the gas preheater. The first valve is located downstream of the residual ammonia outlet.

[0008] The impurity treatment module includes an acid tar tank and a second valve. The acid tar tank is connected to the bottom of the gas preheater and communicates with the lower cavity. The second valve is located upstream of the acid tar tank.

[0009] Optionally, the system also includes a gas purification module, which includes a saturator and a third valve. The saturator is connected to the gas outlet of the gas preheater, and the third valve is located at the gas outlet of the saturator.

[0010] Optionally, the impurity treatment module further includes an acid tar pump and a slag scraper, wherein the slag scraper is connected to the acid tar tank via the acid tar pump.

[0011] Optionally, the impurity treatment module further includes a liquid level detection device and a controller. The liquid level detection device is installed in the acid tar tank, and the controller is communicatively connected to both the acid tar pump and the liquid level detection device. The controller can control the opening or closing of the acid tar pump based on the liquid level signal received from the liquid level detection device.

[0012] Optionally, the heat exchanger is a two-stage heat exchanger, including a first-stage heat exchanger and a second-stage heat exchanger connected in series. The first-stage heat exchanger is connected to the bottom of the second-stage heat exchanger. The first-stage heat exchanger exchanges heat through residual ammonia water, and the second-stage heat exchanger exchanges heat through circulating water.

[0013] Optionally, the ammonia flushing module further includes a residual ammonia tank and a residual ammonia pump, wherein the residual ammonia tank is connected to the residual ammonia inlet of the distributor via the residual ammonia pump.

[0014] Optionally, the ammonia flushing module further includes a residual ammonia filter, which is connected between the distributor and the residual ammonia pump.

[0015] Optionally, the ammonia flushing module further includes an ammonia stripping wastewater pump, an ammonia and wastewater heat exchanger, and an ammonia stripping wastewater cooler. The ammonia stripping wastewater pump is connected to the lower cavity of the ammonia stripping tower. The inlet of the ammonia and wastewater heat exchanger is connected to the ammonia stripping wastewater pump, and its outlet is connected to the ammonia stripping wastewater cooler. The remaining ammonia pump is connected to the ammonia inlet of the ammonia and wastewater heat exchanger. The ammonia outlet of the ammonia and wastewater heat exchanger is connected to the side of the ammonia stripping tower, and the outlet of the ammonia stripping wastewater cooler is connected to the wastewater station.

[0016] Optionally, the ammonia flushing module further includes an ammonia and alkali static mixer, which is connected between the ammonia outlet of the ammonia and wastewater heat exchanger and the ammonia stripping tower.

[0017] Another object of the present invention is to provide a gas preheater flushing method, wherein the gas preheater flushing system described in any of the above-mentioned schemes, when the gas preheater is operating normally, the gas preheater flushing method includes:

[0018] S1. Detect the gas flow rate at the gas inlet of the gas preheater;

[0019] S2. When the gas flow rate drops to the first preset value, open the second valve;

[0020] S3. Wait for the preset time, then open the first valve.

[0021] The beneficial effects of this invention are:

[0022] The gas preheater flushing system provided by this invention is mainly used to flush impurities on the inner wall of the heat exchange tube bundle of a gas preheater. Specifically, the ammonia flushing module includes an ammonia stripping tower, a separator, and a first valve. The separator is located at the top of the ammonia stripping tower, and its residual ammonia outlet is connected to the upper cavity of the gas preheater. The first valve is located downstream of the residual ammonia outlet. Utilizing the heat exchange energy of the separator, the residual ammonia is heated and flushed against the inner wall of the heat exchange tube bundle of the gas preheater. The residual ammonia has good lubrication and fluidity for impurities such as tar, effectively removing impurities and reducing the internal resistance of the gas preheater, making the gas blower's gas delivery smoother. Furthermore, the gas preheater can be flushed without disassembling or reusing a spare gas preheater or saturator, greatly saving cleaning time and improving production efficiency. The impurity treatment module includes an acid tar tank and a second valve. The acid tar tank is connected to the bottom of the gas preheater and communicates with the lower cavity. The second valve is located upstream of the acid tar tank. The acid tar tank is used to hold tar impurities after rinsing, which is beneficial to cleanliness and environmental protection. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the gas preheater provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the gas preheater flushing system provided in an embodiment of the present invention.

[0026] In the picture:

[0027] 100. Gas preheater; 101. Shell; 102. Upper sealing plate; 103. Lower sealing plate; 104. Heat exchange tube bundle; 105. Gas inlet; 106. Gas outlet; 107. Fourth valve;

[0028] 1. Ammonia flushing module; 11. Ammonia stripping tower; 12. Diverter; 13. First valve; 14. Residual ammonia tank; 15. Residual ammonia pump; 16. Residual ammonia filter; 17. Ammonia stripping wastewater pump; 18. Ammonia and wastewater heat exchanger; 19. Ammonia stripping wastewater cooler; 10. Ammonia and alkali static mixer;

[0029] 2. Impurity treatment module; 21. Acid tar tank; 22. Second valve; 23. Acid tar pump; 24. Slag scraper tank;

[0030] 3. Gas purification module; 31. Saturator; 32. Third valve. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," 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 invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element 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 the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" 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. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0039] This embodiment provides a gas preheater flushing system, which is mainly used to flush impurities on the internal tube bundles of the gas preheater 100. For example... Figure 1 As shown, the gas preheater 100 includes a shell 101, an upper sealing plate 102, a lower sealing plate 103, and a heat exchange tube bundle 104. The upper sealing plate 102 and lower sealing plate 103 are spaced apart within the shell 101, dividing the inner cavity of the shell 101 into an upper cavity, a heat exchange cavity, and a lower cavity. The heat exchange tube bundle 104 connects the upper sealing plate 102 and the lower sealing plate 103, and communicates with the upper cavity and the lower cavity. The top of the shell 101 has a gas outlet 106 communicating with the upper cavity, and the bottom of the shell 101 has a gas inlet 105 communicating with the lower cavity. The sides of the shell 101 have a steam inlet and a steam outlet communicating with the heat exchange cavity, with the steam inlet located above the steam outlet. Gas flows through the tubes, and steam flows through the shell. After preheating, the gas enters the saturator from the top to ensure water balance within the saturator.

[0040] Specifically, such as Figure 2 As shown, the gas preheater flushing system includes an ammonia flushing module 1 and an impurity treatment module 2. The ammonia flushing module 1 includes an ammonia stripping tower 11, a separator 12, and a first valve 13. The separator 12 is located at the top of the ammonia stripping tower 11, and its residual ammonia outlet is connected to the upper cavity of the gas preheater 100. The first valve 13 is located downstream of the residual ammonia outlet. The separator 12 is used for heat exchange to raise the temperature of the residual ammonia and flush the inner wall of the heat exchange tube bundle 104 of the gas preheater 100. The residual ammonia has good lubrication and fluidity for impurities such as tar, effectively removing impurities and reducing the internal resistance of the gas preheater 100, making the gas blower's gas delivery smoother. Furthermore, the gas preheater 100 can be flushed without disassembling or reusing the spare gas preheater 100 or saturator 31, significantly saving cleaning time and improving production efficiency. The impurity treatment module 2 includes an acid tar tank 21 and a second valve 22. The acid tar tank 21 is connected to the bottom of the gas preheater 100 and communicates with the lower cavity. The second valve 22 is located upstream of the acid tar tank 21. The acid tar tank 21 is used to hold tar impurities after rinsing, which is beneficial to cleanliness and environmental protection.

[0041] More specifically, the gas preheater flushing system also includes a gas purification module 3. The gas purification module 3 includes a saturator 31 and a third valve 32. The saturator 31 is connected to the gas outlet 106 of the gas preheater 100, and the third valve 32 is located at the outlet of the saturator 31. The tar gas, after being heated by the gas preheater 100, can directly enter the saturator 31 to react with sulfuric acid to form ammonium sulfate crystals. The deammoniated coke oven gas then enters the final cooling and benzene washing process.

[0042] See also Figure 2 The impurity treatment module 2 also includes an acid tar pump 23 and a scraper trough 24. The scraper trough 24 is connected to the acid tar tank 21 via the acid tar pump 23. Impurities washed down by the residual ammonia water enter the scraper trough 24 through the acid tar tank 21. The function of the scraper trough 24 is to separate the impurities and transport them to the slag hopper.

[0043] Furthermore, the impurity treatment module 2 also includes a liquid level detection device and a controller. The liquid level detection device is installed inside the acid tar tank 21 and is used to detect the liquid level height inside the acid tar tank 21. The controller is communicatively connected to both the acid tar pump 23 and the liquid level detection device. The controller can control the opening or closing of the acid tar pump 23 based on the liquid level signal received from the liquid level detection device. When the liquid level in the acid tar tank 21 reaches a certain height, in order to prevent impurities from flowing out, the acid tar pump 23 is turned on to pump the impurities into the slag scraping tank 24. Exemplarily, the liquid level detection device can be a level gauge in the prior art, and the controller can be a PLC in the prior art, etc., and this embodiment is not limited thereto.

[0044] Optionally, in this embodiment, the heat exchanger 12 is a two-stage heat exchanger, including a first-stage heat exchanger and a second-stage heat exchanger connected in series. The first-stage heat exchanger is connected to the bottom of the second-stage heat exchanger. The first-stage heat exchanger exchanges heat through residual ammonia water, while the second-stage heat exchanger exchanges heat through circulating water. The first-stage heat exchanger has a residual ammonia water inlet and a residual ammonia water outlet, while the second-stage heat exchanger has a circulating water inlet and a circulating water outlet.

[0045] See also Figure 2 To supply residual ammonia water to the ammonia stripping tower 11, the ammonia water flushing module 1 also includes a residual ammonia water tank 14 and a residual ammonia water pump 15. The residual ammonia water tank 14 is connected to the residual ammonia water inlet of the distributor 12 via the residual ammonia water pump 15. Furthermore, the ammonia water flushing module 1 also includes a residual ammonia water filter 16. The residual ammonia water filter 16 is connected between the distributor 12 and the residual ammonia water pump 15 to filter out impurities in the residual ammonia water.

[0046] Specifically, the ammonia flushing module 1 also includes an ammonia stripping wastewater pump 17, an ammonia water and wastewater heat exchanger 18, and an ammonia stripping wastewater cooler 19. The ammonia stripping wastewater pump 17 is connected to the lower cavity of the ammonia stripping tower 11, the inlet of the ammonia water and wastewater heat exchanger 18 is connected to the ammonia stripping wastewater pump 17, and its outlet is connected to the ammonia stripping wastewater cooler 19. The remaining ammonia water pump 15 is connected to the ammonia water inlet of the ammonia water and wastewater heat exchanger 18, the ammonia water outlet of the ammonia water and wastewater heat exchanger 18 is connected to the side of the ammonia stripping tower 11, and the outlet of the ammonia stripping wastewater cooler 19 is connected to the wastewater station.

[0047] More specifically, the ammonia flushing module 1 also includes an ammonia and alkali static mixer 10. The ammonia and alkali static mixer 10 is connected between the ammonia outlet of the ammonia and wastewater heat exchanger 18 and the ammonia stripping tower 11, and is used to add desulfurized alkali solution to the remaining ammonia water.

[0048] This embodiment also provides a gas preheater flushing method, employing a gas preheater flushing system according to any of the above-described schemes. When the gas preheater 100 is operating normally, the gas preheater 100 flushing method includes:

[0049] S1. Detect the gas flow rate at the gas inlet of the gas preheater 100;

[0050] S2. When the gas flow rate drops to the first preset value, open the second valve 22;

[0051] S3. Wait for the preset time, then open the first valve 13.

[0052] Specifically, during coke oven shutdown and maintenance, the gas preheater 100 can still operate normally, but the amount of gas generated by the coke oven gradually decreases, and the gas flow rate at the gas inlet of the gas preheater 100 also gradually decreases. In step S2, the first preset value is 30000m³. 3 / h.

[0053] When the gas flow rate drops to the first preset value, the first valve 22 is opened to keep the pipeline unobstructed. Then, after waiting for a preset time (the preset time can be selected as 1-5 seconds), the first valve 13 is opened to flush the gas preheater 100 online. At the same time, the liquid level in the acid tar tank 21 is observed. When the liquid level in the acid tar tank 21 reaches a certain height, in order to prevent impurities from flowing out, the acid tar pump 23 is turned on to pump the impurities into the slag scraper 24.

[0054] The gas preheater flushing method provided in this embodiment can also be used for offline flushing of the gas preheater 100, including the following steps:

[0055] S100, standby preheater and saturator 31;

[0056] S200, Close the third valve 32 and the fourth valve 107;

[0057] S300, Open the second valve 22;

[0058] S400, Open the first valve 13.

[0059] Specifically, closing the third valve 32 and the fourth valve 107 ensures that no gas flows through the gas preheater 100; opening the first valve 13 keeps the pipeline unobstructed; opening the first valve 13 allows the gas preheater 100 to be flushed offline with the remaining ammonia water. Simultaneously, the liquid level in the acid tar tank 21 is observed. When the liquid level in the acid tar tank 21 reaches a certain height, to prevent impurities from flowing out, the acid tar pump 23 is turned on to pump the impurities into the slag scraper 24.

[0060] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A coal gas preheater flushing system for flushing impurities on the tube bundle inside a coal gas preheater (100), the coal gas preheater (100) comprising a shell (101), an upper sealing plate (102), a lower sealing plate (103) and a heat exchange tube bundle (104), the upper sealing plate (102) and the lower sealing plate (103) being arranged in the shell (101) at intervals, separating the inner cavity of the shell (101) into an upper cavity, a heat exchange cavity and a lower cavity, the heat exchange tube bundle (104) being connected between the upper sealing plate (102) and the lower sealing plate (103) and communicating the upper cavity and the lower cavity, the top of the shell (101) being provided with a coal gas outlet (106) communicating with the upper cavity, the bottom of the shell (101) being provided with a coal gas inlet (105) communicating with the lower cavity, the side of the shell (101) being provided with a steam inlet and a steam outlet communicating with the heat exchange cavity respectively, the steam inlet being located above the steam outlet, characterized in that, The coal gas preheater flushing system further comprises: An ammonia water flushing module (1) comprising an ammonia evaporation tower (11), a partial condenser (12) and a first valve (13), the partial condenser (12) is arranged at the top of the ammonia evaporation tower (11), the remaining ammonia water outlet of the partial condenser (12) is communicated with the upper cavity of the coal gas preheater (100), and the first valve (13) is arranged downstream of the remaining ammonia water outlet; A foreign matter treatment module (2) comprising an acid tar tank (21) and a second valve (22), the acid tar tank (21) is connected to the bottom of the coal gas preheater (100) and communicated with the lower cavity, and the second valve (22) is arranged upstream of the acid tar tank (21); Further comprising a coal gas purification module (3), the coal gas purification module (3) comprises a saturator (31) and a third valve (32), the saturator (31) is communicated with the coal gas outlet (106) of the coal gas preheater (100), and the third valve (32) is arranged at the gas outlet of the saturator (31); The offline flushing of the coal gas preheater (100) comprises the following steps: S100, using a standby preheater and the saturator (31); S200, closing the third valve (32) and the fourth valve (107); S300, opening the second valve (22); S400, opening the first valve (13); Closing the third valve (32) and the fourth valve (107) can ensure that there is no gas flow in the coal gas preheater (100); opening the first valve (13) can keep the pipeline unobstructed; opening the first valve (13) can flush the coal gas preheater (100) offline by using the remaining ammonia water.

2. The coal gas preheater flushing system of claim 1, wherein, The foreign matter treatment module (2) further comprises an acid tar pump (23) and a slag scraping tank (24), the slag scraping tank (24) is communicated with the acid tar tank (21) through the acid tar pump (23).

3. The coal gas preheater flush system of claim 2, wherein, The foreign matter treatment module (2) further comprises a liquid level detection device and a controller, the liquid level detection device is arranged in the acid tar tank (21), the controller is communicatively connected with the acid tar pump (23) and the liquid level detection device, and the controller can control the opening or closing of the acid tar pump (23) according to the liquid level signal received from the liquid level detection device.

4. The coal gas preheater flush system of claim 1, wherein, The partial condenser (12) is a two-section heat exchange partial condenser comprising a first-section partial condenser and a second-section partial condenser which are communicated, the first-section partial condenser is connected to the bottom of the second-section partial condenser, the first-section partial condenser exchanges heat by using the remaining ammonia water, and the second-section partial condenser exchanges heat by using circulating water.

5. The coal gas preheater flush system of claim 1, wherein, The ammonia water flushing module (1) further comprises a remaining ammonia water tank (14) and a remaining ammonia water pump (15), the remaining ammonia water tank (14) is communicated to the remaining ammonia water inlet of the partial condenser (12) through the remaining ammonia water pump (15).

6. The coal gas preheater flush system of claim 5, wherein, The ammonia water flushing module (1) further comprises a remaining ammonia water filter (16), the remaining ammonia water filter (16) is connected between the partial condenser (12) and the remaining ammonia water pump (15).

7. The coal gas preheater flush system of claim 5, wherein, The ammonia water flushing module (1) further comprises an ammonia evaporation wastewater pump (17), an ammonia water and wastewater heat exchanger (18) and an ammonia evaporation wastewater cooler (19), the ammonia evaporation wastewater pump (17) is communicated with the lower cavity of the ammonia evaporation tower (11), the water inlet of the ammonia water and wastewater heat exchanger (18) is communicated with the ammonia evaporation wastewater pump (17), the water outlet of the ammonia water and wastewater heat exchanger (18) is communicated with the ammonia evaporation wastewater cooler (19), the remaining ammonia water pump (15) is communicated with the ammonia water inlet of the ammonia water and wastewater heat exchanger (18), the ammonia water outlet of the ammonia water and wastewater heat exchanger (18) is communicated with the side of the ammonia evaporation tower (11), and the water outlet of the ammonia evaporation wastewater cooler (19) is communicated with a wastewater station.

8. The coal gas preheater flush system of claim 7, wherein, The ammonia water flushing module (1) further comprises an ammonia water and alkali static mixer (10) connected between the ammonia water outlet of the ammonia water and wastewater heat exchanger (18) and the ammonia evaporation tower (11).

9. A method of purging a gas preheater using a gas preheater purging system according to any one of claims 1 to 8, characterised in that, When the gas preheater (100) is in normal operation, the gas preheater (100) flushing method comprises: S1, detecting the gas flow value at the gas inlet of the gas preheater (100); S2, when the gas flow value decreases to a first preset value, opening the second valve (22); S3, waiting for a preset time, and opening the first valve (13).

Images