Device for reducing differential pressure of smoke cooler on line and using method thereof

Abstract

The invention discloses a device for reducing differential pressure of a smoke cooler on line, which relates to the field of thermal power generation and comprises a smoke cooler body, and the smoke cooler body comprises a water inlet pipe arranged on the smoke cooler body and a water outlet pipe arranged on the smoke cooler body; the adjusting pipe assembly comprises a steam inlet pipe part arranged on the water inlet pipe and a steam outlet pipe part arranged on the water outlet pipe and is used for introducing steam into the smoke cooler body, the solid ammonium bisulfate is subjected to phase change, a fly ash adhesion structure is damaged, and the differential pressure of the smoke cooler body is reduced; according to the smoke cooler, the problem of blocking of the smoke cooler body is solved by monitoring the pressure difference change of the smoke cooler body on line, introducing steam to heat the smoke cooler body and rapidly cleaning fly ash through the rake type soot blower, so that the pressure difference is effectively reduced, and non-stop cleaning is realized in the whole process; 2000 tons of water for physical high-pressure flushing in a traditional method is reduced, and the manual flushing cost is reduced. The improved system is easy to operate, high in equipment reliability and stable in operation.

Description

Technical Field

[0001] The present invention relates to the field of thermal power generation, and particularly to an on-line device for reducing the differential pressure of a flue gas cooler. Background Art

[0002] In recent years, the energy conservation and environmental protection work in thermal power plants has been continuously deepened, and boiler flue gas coolers have been widely used. With the operation of flue gas coolers in the actual production process, problems such as blockage and leakage have become more and more. The blockage of the flue gas cooler leads to an increase in differential pressure, resulting in limited unit output and induced draft fan stall; the leakage of the flue gas cooler (corrosion, erosion, stress effect) causes it to withdraw from operation, affecting heat recovery and dust removal efficiency; the ash accumulation in the flue gas cooler leads to a deterioration of the heat exchange effect and an increase in differential pressure, etc.

[0003] Excessive ammonia escape rate caused by denitrification will accelerate the formation of ammonium bisulfate. Liquid ammonium bisulfate is a very sticky substance. When ammonium bisulfate aggregates on the surface of an object in liquid form or is dispersed in flue gas in the form of droplets, it will bond the fly ash in the flue gas and at the same time adhere to the surface of the equipment, causing deposition. The current inlet flue gas temperature of the flue gas cooler is about 150°C, and less solid ammonium bisulfate is generated, and the blockage problem is less likely to occur. When the flue gas temperature continues to drop, the liquid phase ammonium bisulfate increases and begins to solidify, resulting in the blockage of the flue gas cooler gradually intensifying from front to back. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that it is difficult to clean the ammonium bisulfate adhering to the fly ash after solidification at the inlet of the existing flue gas cooler, resulting in blockage of the flue gas cooler and an increase in differential pressure.

[0005] The above technical problem is solved by the following technical solution: The present invention provides an on-line device for reducing the differential pressure of a flue gas cooler, which includes a flue gas cooler body. The flue gas cooler body includes a water inlet pipe provided on the flue gas cooler main body and a water outlet pipe provided on the flue gas cooler main body.

[0006] A regulating pipe assembly, the regulating pipe assembly includes a steam inlet pipe portion provided on the water inlet pipe and a steam outlet pipe portion provided on the water outlet pipe, for introducing steam into the flue gas cooler body, so that solid ammonium bisulfate undergoes a phase change, destroys the fly ash adhesion structure, and reduces the differential pressure of the flue gas cooler body.

[0007] In a preferred embodiment of the on-line device for reducing the differential pressure of the flue gas cooler of the present invention: the steam inlet pipe portion includes a steam inlet pipe provided on the water inlet pipe and a control valve provided on the steam inlet pipe.

[0008] In a preferred embodiment of the online differential pressure reducing device for a smoke cooler according to the present invention: It further includes a rake-type soot blower, and a steam supply pipe is provided on the rake-type soot blower. The rake-type soot blower is installed on the smoke cooler body and is used to clean the fly ash adhered to the smoke cooler body; one end of the steam inlet pipe is connected to the water inlet pipe, and the other end of the steam inlet pipe is connected to the steam supply pipe.

[0009] In a preferred embodiment of the online differential pressure reducing device for a smoke cooler according to the present invention: The steam outlet pipe portion includes a steam outlet pipe provided on the water outlet pipe and a connecting pipe provided on the steam outlet pipe.

[0010] In a preferred embodiment of the online differential pressure reducing device for a smoke cooler according to the present invention: It further includes a heating ash hopper; a drain pipe for connecting with the heating ash hopper is provided on the rake-type soot blower; the drain pipe is communicated with the connecting pipe.

[0011] In a preferred embodiment of the online differential pressure reducing device for a smoke cooler according to the present invention: A water inlet horizontal pipe is provided on the water inlet pipe, and the steam inlet pipe is arranged in parallel with the water inlet horizontal pipe.

[0012] To solve the above technical problems, the present invention also proposes a use method of the online differential pressure reducing device for a smoke cooler, which specifically includes the following steps:

[0013] When the smoke cooler body is operating, detect the pressure difference. When the differential pressure is higher than the set value, drain the cooling water in the smoke cooler body;

[0014] Slowly introduce steam into the smoke cooler body through the steam inlet pipe portion to preheat the smoke cooler body;

[0015] Quickly introduce steam into the smoke cooler body through the steam inlet pipe portion, so that the temperature of the smoke cooler body rises, and the solid ammonium bisulfate attached to the smoke cooler body becomes liquid and then gradually becomes gaseous, destroying the fly ash adhesion structure;

[0016] Blow soot into the smoke cooler body through the rake-type soot blower. At this time, the damaged fly ash adhesion structure is easy to clean up;

[0017] When it is monitored that the pressure difference returns to the set value, discharge the steam and re-introduce cooling water for cooling to achieve cleaning without shutting down the machine.

[0018] In a preferred embodiment of the use method of the online differential pressure reducing device for a smoke cooler according to the present invention: The steam led out from the connecting pipe is introduced into the heating ash hopper for recycling.

[0019] In a preferred embodiment of the method for using the device for online reducing the differential pressure of the flue gas cooler according to the present invention: precisely control the temperature of the flue gas cooler body to be 240 - 280 °C.

[0020] In a preferred embodiment of the method for using the device for online reducing the differential pressure of the flue gas cooler according to the present invention: the steam pressure is 0.8 - 1.2 MPa.

[0021] The beneficial effects of the present invention are as follows: By online monitoring the change of the differential pressure of the flue gas cooler body, after the differential pressure value is higher than the set value, the cooling water is drained, and then steam is introduced to heat up the flue gas cooler body, so that the ammonium bisulfate solid attached to the flue gas cooler body becomes a gas, and the rake type soot blower quickly clears the fly ash, solving the blockage problem of the flue gas cooler body, thus effectively reducing the differential pressure; after the differential pressure is restored, by adjusting the regulating pipe assembly, cooling water is introduced into the flue gas cooler body again for production, and the whole process realizes cleaning without shutting down the machine; it reduces 2000 tons of water used for physical high-pressure flushing in the traditional method, reduces 100% of the discharged flushing wastewater, and reduces the manual flushing cost. The transformed system is simple to operate, has high equipment reliability and stable operation; it saves 160,000 yuan of manual flushing cost per unit, reduces the power consumption of the induced draft fan by 0.05%, and saves 1.7 million kW·h of plant electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention and do not limit the present invention. Among them:

[0023] Figure 1 Shows the overall structural schematic diagram of the present invention;

[0024] Figure 2 Shows the differential pressure change diagram after the steam heating of the flue gas cooler body described in A2 of the present invention is put into operation. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with the specific embodiments and the drawings.

[0026] The terms used in the present invention are those general terms that are currently widely used in the art in consideration of the functions of the present invention, but these terms can change according to the intentions of those of ordinary skill in the art, precedents or new technologies in the art. In addition, specific terms can be selected by the applicant, and in this case, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but based on the meanings of the terms and the overall description of the present invention.

[0027] Reference Figure 1 Figure 1 , this embodiment provides an online differential pressure reduction device for a flue gas cooler, which includes a flue gas cooler body 1. The flue gas cooler body 1 includes a water inlet pipe 11 provided on the flue gas cooler main body, and a water outlet pipe 12 provided on the flue gas cooler main body; and the water inlet pipe 11 and the water outlet pipe 12 can introduce and discharge cooling water into and out of the flue gas cooler body 1.

[0028] A regulating pipe assembly 2, the regulating pipe assembly 2 includes a steam inlet pipe portion 21 provided on the water inlet pipe 11, and a steam outlet pipe portion 22 provided on the water outlet pipe 12, which is used to introduce steam into the flue gas cooler body 1, so that solid ammonium bisulfate undergoes a phase change, destroys the fly ash adhesion structure, and reduces the differential pressure of the flue gas cooler body 1. After the flue gas cooler body 1 has been in use for a period of time, ammonium bisulfate liquid adheres to the flue gas cooler body 1, adheres to the fly ash, becomes solid after the temperature drops, causes blockage of the flue gas cooler body 1, and causes the differential pressure to rise. At this time, the cooling water in the flue gas cooler body 1 is discharged through the water outlet pipe 12 to empty the cooling water in the flue gas cooler body 1, cut off the cooling effect of the cooling water on the flue gas cooler body 1, and at the same time, through the discharge of the cooling water, the impurities in the flue gas cooler body 1 can be cleaned to avoid corrosion and damage of the pipeline caused by impurity deposition in the flue gas cooler body 1; then steam is introduced into the flue gas cooler body 1 through the water inlet pipe 11 and discharged through the steam outlet pipe portion 22. At this time, the steam heats up the flue gas cooler body 1, so that the solid ammonium bisulfate adhering to the flue gas cooler body 1 becomes a gas. At this time, the fly ash adsorbed and adhered by ammonium bisulfate can be effectively and quickly cleaned, solving the blockage problem of the flue gas cooler body 1, thus effectively reducing the differential pressure; after the differential pressure is restored, by adjusting the regulating pipe assembly 2, cooling water is introduced into the flue gas cooler body 1 again for production, and the whole process realizes cleaning without stopping the machine; it reduces 2000 tons of water used for physical high-pressure flushing in the traditional method, reduces 100% of the flushing wastewater emissions, and reduces the manual flushing cost. The transformed system is simple to operate, has high equipment reliability and stable operation; it saves 160,000 yuan of manual flushing cost per unit, reduces the power consumption of the induced draft fan by 0.05%, and saves 1.7 million kW·h of plant electricity.

[0029] As an alternative embodiment, the steam inlet pipe portion 21 includes a steam inlet pipe 211 provided on the water inlet pipe 11, and a control valve 212 provided on the steam inlet pipe 211. The control valve 212 controls the size of the opening channel of the steam inlet pipe 211. When the steam is initially introduced, the opening channel controlled by the control valve 212 is relatively small. At this time, the steam slowly enters the water inlet pipe 11 to preheat the water inlet pipe 11, the smoke cooler body 1, and the water outlet pipe 12 as a whole. Then, the steam inlet channel is fully opened, so that the steam quickly enters the smoke cooler body 1, thereby realizing the rapid heating of the smoke cooler body 1, vaporizing the liquid ammonium bisulfate, quickly cleaning the dust, and then resuming the introduction of cooling water to continue working. At the same time, the control valve 212 can completely cut off the steam inlet pipe 211, avoiding the cooling water entering the steam inlet pipe 211 when the cooling water is introduced. By adjusting the steam inlet and steam return openings of the smoke cooler body 1 through the control valve 212, the pipe wall temperature is accurately controlled to 240 - 280 °C (error ±5 °C). During one overhaul cycle of the unit, heating can be regularly or irregularly input according to the differential pressure rise of the smoke cooler body 1, effectively controlling the differential pressure rise and reducing the power consumption of the induced draft fan.

[0030] Preferably, it further includes a rake type soot blower 3. A steam supply pipe 31 is provided on the rake type soot blower 3. The rake type soot blower 3 is installed on the smoke cooler body 1 and is used to clean the fly ash adhered to the smoke cooler body 1. One end of the steam inlet pipe 211 is connected to the water inlet pipe 11, and the other end of the steam inlet pipe 211 is connected to the steam supply pipe 31. By connecting the other end of the steam inlet pipe 211 to the steam supply pipe 31, only this section of the steam inlet pipe 211 needs to be added, avoiding the addition of a large number of pipes and reducing the cost. By setting the steam source at the steam inlet valve of the rake type soot blower 3, the function of the steam supply pipe 31 is made more abundant.

[0031] As Figure 1 As shown, the steam outlet pipe portion 22 includes a steam outlet pipe 221 provided on the water outlet pipe 12, and a connecting pipe 222 provided on the steam outlet pipe 221. By providing the steam outlet pipe 221, the steam passing through the smoke cooler body 1 can be discharged. By providing the connecting pipe 222, the output steam can be guided to other devices for reusing the heat.

[0032] As an alternative embodiment, it further includes a heating ash hopper 4. A drain pipe 32 for connecting with the heating ash hopper 4 is provided on the rake type soot blower 3. The drain pipe 32 is communicated with the connecting pipe 222. Connecting the connecting pipe 222 with the drain pipe 32 can guide the output steam to the heating ash hopper 4 for the electrostatic precipitator device, avoiding energy waste.

[0033] As an alternative embodiment, an inlet water horizontal pipe 111 is provided on the inlet water pipe 11, and the steam inlet pipe 211 is arranged in parallel with the inlet water horizontal pipe 111. The space at the inlet water horizontal pipe 111 is relatively large, which is convenient for installing the steam inlet pipe 211 and also for operating the control valve 212 on the steam inlet pipe 211.

[0034] In summary, for the first time, the steam phase change principle is applied to the ash accumulation treatment of the flue gas cooler body 1, breaking through the traditional physical ash cleaning thinking, providing a new paradigm for the treatment of sticky ash accumulation, realizing the online reduction of the differential pressure of the flue gas cooler body 1, and breaking through the traditional high-pressure water flushing mode after shutdown; establishing a thermodynamic model for the multiphase transformation of ammonium bisulfate, introducing medium-pressure steam (0.8 - 1.2 MPa) to heat the heating surface, raising the wall temperature to above 240 °C, causing the solid ammonium bisulfate to undergo a phase change (solid → liquid → gas), and destroying the ash adhesion structure; adjusting the steam inlet and steam return openings of the flue gas cooler body 1 through the control valve 212 to accurately control the wall temperature to 240 - 280 °C (error ±5 °C). During one overhaul period of the unit, heating can be regularly or irregularly input according to the increase in the differential pressure of the flue gas cooler body 1, effectively controlling the increase in differential pressure and reducing the power consumption of the induced draft fan; reducing the water consumption for physical high-pressure flushing by 2000 tons in the traditional method, achieving 100% emission reduction of flushing wastewater, and reducing the manual flushing cost. The transformed system is simple to operate, has high equipment reliability, and operates stably.

[0035] Implementation effect of the achievement:

[0036] In 2024, in the 3rd furnace of Jinggangshan Power Plant, the differential pressure of the flue gas cooler increased rapidly due to the accumulation of ammonium bisulfate. During that period, the maximum differential pressure of the flue gas cooler in Column A1 was 3918 Pa, and the maximum differential pressure of the flue gas cooler in Column A2 was 4043 Pa. After 2 hours of steam heating was input into the flue gas cooler in Column A2, by raising the wall temperature of the A2 flue gas cooler and combining steam soot blowing and flue gas scouring, the differential pressure of the A-side flue gas cooler began to decrease rapidly. Among them, the heating temperature inside the flue gas cooler module reached above 280 °C. The specific differential pressure situation is as Figure 2 shown, and the differential pressure is in a continuous decreasing state; Figure 2 Among them, under the action of steam, the flue gas cannot be cooled down, and the flue gas temperature remains at a high temperature for a long time as shown by the blue line in Figure 2 .

[0037] Comparing the same load of 385 MW, before the steam heating of the flue gas cooler was input, the differential pressures of the flue gas coolers in Column A1 and A2 were 3362 Pa and 3514 Pa respectively. After the steam heating of the flue gas cooler was input and the wall temperature of the flue gas cooler was raised to above 280 °C, the differential pressures of the flue gas coolers in Column A1 and A2 were 877 Pa and 1034 Pa respectively. The differential pressure of the A-column flue gas cooler decreased by 2480 Pa, and the parameters of the system basically recovered, and the unit carried the load normally.

[0038] Table of index changes before and after steam is introduced into A2

[0039] Index Before heating After heating Reduction Differential pressure of the main body of the flue gas cooler (Pa) 3514 1034 70％ Induced draft fan current (A) 500 450 10％ Annual water saving (tons) 2000 0 100％

[0040] After introducing steam, the temperature of the pipe wall is raised online to above 240 °C, promoting the phase change of ammonium bisulfate from solid state to gaseous state, dynamically removing ash deposits, enabling the main body of the flue gas cooler to discharge flue gas smoothly, and significantly reducing the differential pressure of the main body of the flue gas cooler; after the differential pressure drops, fly ash can pass through the main body of the flue gas cooler smoothly without obstruction, so the current required by the induced draft fan is reduced, effectively saving electric energy; at the same time, the ash deposits are cleaned by introducing steam, avoiding manual cleaning with a high-pressure water gun, reducing 2000 tons of water used for physical high-pressure flushing by the traditional method, reducing 100% of the discharged flushing wastewater, and reducing the manual flushing cost.

[0041] Furthermore, based on the above device for online reducing the differential pressure of the flue gas cooler, this embodiment provides a method for using the device for online reducing the differential pressure of the flue gas cooler, which specifically includes the following steps:

[0042] S1: When the differential pressure is detected during the operation of the main body 1 of the flue gas cooler, and when the differential pressure is higher than the set value, the cooling water in the main body 1 of the flue gas cooler is drained.

[0043] S2: Slowly introduce steam into the main body 1 of the flue gas cooler through the steam inlet pipe part 21 to preheat the main body 1 of the flue gas cooler.

[0044] S3: Quickly introduce steam into the main body 1 of the flue gas cooler through the steam inlet pipe part 21, so that the temperature of the main body 1 of the flue gas cooler rises, and the solid ammonium bisulfate attached to the main body 1 of the flue gas cooler becomes liquid and then gradually becomes gaseous, destroying the adhesion structure of fly ash; by adjusting the opening degrees of the steam inlet and steam return of the flue gas cooler, precise control of the temperature of the pipe wall of the flue gas cooler can be achieved.

[0045] S4: Blow ash into the main body 1 of the flue gas cooler through the rake type soot blower 3. At this time, the destroyed fly ash adhesion structure is easy to clean; frequency: 15 times / h, intensity: 60% of the conventional soot blowing, combined with the change trend of the temperature of the pipe wall of the flue gas cooler, realize dynamic ash deposit removal and optimize the soot blowing logic, reducing the power consumption of the induced draft fan (0.05%) and the auxiliary power consumption of the plant (1.7 million kW·h / year).

[0046] S5: When it is monitored that the differential pressure returns to the set value, discharge the steam and re-introduce cooling water for cooling to achieve cleaning without shutting down. During one overhaul period of the unit, heating can be regularly or irregularly input according to the increase in the differential pressure of the flue gas cooler, effectively controlling the increase in the differential pressure, reducing the power consumption of the induced draft fan; reducing 2000 tons of water used for physical high-pressure flushing by the traditional method, reducing 100% of the discharged flushing wastewater, saving energy and protecting the environment, and reducing the manual flushing cost; effectively controlling and reducing the differential pressure of the flue gas cooler, avoiding problems such as air robbing and stall of the induced draft fan during operation, and improving the safety of the boiler operation.

[0047] As an alternative embodiment, the steam led out at the connecting pipe 222 is introduced into the heating ash hopper 4 for recycling. Recycling the steam in the smoke cooler body 1 to the heating ash hopper 4 for heating can avoid waste of high-quality steam.

[0048] As an alternative embodiment, the temperature of the smoke cooler body 1 is precisely controlled to be 240 - 280 °C.

[0049] As an alternative embodiment, the steam pressure is 0.8 - 1.2 MPa.

[0050] Finally, it should be noted that the methods and devices described in detail above are only embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. An online device for reducing the differential pressure of a smoke cooler, characterized in that: including, a flue gas cooler body (1), the flue gas cooler body (1) includes a water inlet pipe (11) arranged on the flue gas cooler main body, and a water outlet pipe (12) arranged on the flue gas cooler main body; and a regulating pipe assembly (2), the regulating pipe assembly (2) includes a steam inlet pipe part (21) arranged on the water inlet pipe (11), and a steam outlet pipe part (22) arranged on the water outlet pipe (12), for introducing steam into the flue gas cooler body (1), so that solid ammonium bisulfate undergoes a phase change, destroys the fly ash adhesion structure, and reduces the differential pressure of the flue gas cooler body (1).

2. The online differential pressure reduction device for a smoke cooler according to claim 1, characterized in that: The steam inlet pipe part (21) includes a steam inlet pipe (211) arranged on the water inlet pipe (11), and a control valve (212) arranged on the steam inlet pipe (211).

3. The online differential pressure reduction device for a smoke cooler according to claim 2, wherein: It further includes a rake type soot blower (3), a steam supply pipe (31) is provided on the rake type soot blower (3), and the rake type soot blower (3) is installed on the flue gas cooler body (1) for cleaning the fly ash adhered to the flue gas cooler body (1); one end of the steam inlet pipe (211) is connected to the water inlet pipe (11), and the other end of the steam inlet pipe (211) is connected to the steam supply pipe (31).

4. The online differential pressure reduction device for a smoke cooler according to claim 3, wherein: The steam outlet pipe part (22) includes a steam outlet pipe (221) arranged on the water outlet pipe (12), and a connecting pipe (222) arranged on the steam outlet pipe (221).

5. The online differential pressure reduction device for a smoke cooler according to claim 4, characterized in that: It further includes a heating ash hopper (4); a drain pipe (32) for connecting with the heating ash hopper (4) is provided on the rake type soot blower (3); the drain pipe (32) is communicated with the connecting pipe (222).

6. The online differential pressure reduction device for a smoke cooler according to claim 5, wherein: A water inlet horizontal pipe (111) is provided on the water inlet pipe (11), and the steam inlet pipe (211) is arranged in parallel with the water inlet horizontal pipe (111).

7. A method for using an online differential pressure reduction device for a smoke cooler, characterized in that: Specifically, it includes the following steps: When the flue gas cooler body (1) is operating, detect the pressure difference. When the differential pressure is higher than the set value, drain the cooling water in the flue gas cooler body (1); Slowly introduce steam into the flue gas cooler body (1) through the steam inlet pipe part (21) to preheat the flue gas cooler body (1); Quickly introduce steam into the flue gas cooler body (1) through the steam inlet pipe part (21), so that the flue gas cooler body (1) heats up, and the solid ammonium bisulfate attached to the flue gas cooler body (1) becomes liquid and then gradually becomes gaseous, destroying the fly ash adhesion structure; Blow soot into the flue gas cooler body (1) through the rake type soot blower (3). At this time, the damaged fly ash adhesion structure is easy to clean; When it is monitored that the pressure difference returns to the set value, discharge the steam and re-introduce cooling water for cooling to achieve cleaning without shutting down the machine.

8. The method for using the device for online reducing the differential pressure of the smoke cooler according to claim 7, characterized in that: Introduce the steam derived from the connecting pipe (222) into the heating ash hopper (4) for recycling.

9. The method for using the online differential pressure reduction device of a smoke cooler according to claim 8, characterized in that: Precisely control the temperature of the flue gas cooler body (1) to be 240 - 280 °C.

10. The method for using the device for online reducing the differential pressure of the smoke cooler according to claim 9, characterized in that: The steam pressure is 0.8 - 1.2 MPa.

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