Flushing pipeline of pyrolysis furnace in denitration system

Abstract

The present invention provides a flushing pipeline for a pyrolysis furnace in a denitration system, and belongs to the field of mechanical technology. It solves the problem that the existing denitration system has poor urea solution flushing effect. The flushing pipeline for the pyrolysis furnace in the denitration system includes a cold water pipe, a hot water branch pipe 1, and a flushing pipe for flushing urea solution. The outlet of the cold water pipe and the outlet of the hot water branch pipe 1 are both connected to the flushing pipe. The flushing pipeline also includes a condensate water pipe led out from the boiler unit where the denitration system is located. The inlet of the cold water pipe and the inlet of the hot water branch pipe 1 are both connected to the condensate water pipe. The hot water branch pipe 1 is arranged along the outside of the flue on the boiler unit where the denitration system is located. A thermometer is provided on the flushing pipe, and the flushing pipeline also includes a hot water regulating valve capable of regulating the hot water flow and a cold water regulating valve capable of regulating the cold water flow. It has the advantages of good flushing effect and reduced heat loss of the boiler unit.

Description

Technical Field

[0001] The invention belongs to the technical field of urea ammonia production and relates to a flushing pipeline, in particular to a flushing pipeline of a pyrolysis furnace in a denitration system. Background Art

[0002] With the development of domestic social economy, the progress of science and technology, and the improvement of people's living standards, the society has paid unprecedented attention to the environment. Flue gas denitrification device has become an indispensable part of power plant construction after desulfurization device, and SCR flue gas denitrification technology is the most widely used and mature denitrification technology with relatively high denitrification efficiency in power plants at home and abroad. At present, in the selective catalytic reduction denitrification (SCR) process, most reductants use urea method ammonia production system. The urea method is to first completely dissolve urea solid particles in desalted water in the container, and then transport the urea solution with qualified concentration and temperature to the storage tank, and then transport it to the urea solution metering module by a high-flow circulation pump, and then enter the urea spray gun through the regulating valve to the pyrolysis furnace for reaction to generate ammonia. The ammonia enters the flue and reacts with nitrogen oxides in the flue gas to generate nitrogen and water to reduce the concentration of nitrogen oxides in the flue gas.

[0003] When the urea spray gun is out of operation, the pipeline for conveying urea solution and the inside of the spray gun need to be flushed. Most power plants directly use cold water as flushing water, but the temperature of cold water is low, and the flushing effect on urea solution is very poor, and it cannot be thoroughly flushed. This is mainly because the crystallization temperature of urea solution is relatively low. During the flushing process, it is easy for some urea solution to crystallize with cold water and adhere to the pipe wall. When the spray gun is put into use again, the urea crystals will fall off, which can easily cause the nozzle of the spray gun to be blocked, and then cause the urea solution to flow back to the compressed air pipeline, so that the urea solution cannot or only partially can enter the pyrolysis furnace for decomposition, thereby affecting the generation of ammonia, affecting the denitrification efficiency, and causing the nitrogen oxide concentration at the outlet of the denitrification system reactor to exceed the standard, which seriously affects the safe, economical and environmentally friendly operation of the unit.

[0004] In order to solve the problem of urea solution crystallization causing blockage of the spray gun and pipeline, a common solution is to directly lead a hot water pipeline from the boiler unit to flush the urea solution spray gun and pipeline in the pyrolysis furnace to avoid urea solution crystallization causing blockage of the urea spray gun or pipeline. For example, application No. 201520812931.1 discloses a flushing pipeline for preventing blockage of the urea spray gun and pipeline of a denitrification pyrolysis furnace, and application No. 201320413111.6 discloses a heating and flushing system for a urea solution delivery pipeline. However, this method will increase the heat loss of the entire boiler unit. Summary of the invention

[0005] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a flushing pipeline for a pyrolysis furnace in a denitration system. The technical problem to be solved is how to improve the flushing effect of the pyrolysis furnace.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A flushing pipeline for a pyrolysis furnace in a denitration system, the flushing pipeline comprising a cold water pipe, a hot water branch pipe 1 and a flushing pipe for flushing a urea solution, the outlet of the cold water pipe and the outlet of the hot water branch pipe 1 are both connected to the flushing pipe, and is characterized in that the flushing pipeline also comprises a condensate water pipe led out from a boiler unit where the denitration system is located, the inlet of the cold water pipe and the inlet of the hot water branch pipe 1 are both connected to the condensate water pipe, the hot water branch pipe 1 is arranged along the outside of a flue on the boiler unit where the denitration system is located, a thermometer is provided on the flushing pipe, and the flushing pipeline also comprises a hot water regulating valve capable of regulating the hot water flow rate and a cold water regulating valve capable of regulating the cold water flow rate.

[0008] When it is necessary to flush the urea solution in the pyrolysis furnace, part of the condensate in the condensate pipe flows into hot water branch pipe one, and the other part of the condensate flows into branch pipe two. Since hot water branch pipe one is arranged along the outside of the flue on the boiler unit where the denitrification system is located, and the flue radiates very high heat outward due to the existence of flue gas inside, hot water branch pipe one will exchange heat with the high heat radiated from the outside of the flue, thereby heating the condensate flowing into hot water branch pipe one to form hot water with high temperature. Finally, the unit staff adjusts the flow rate of cold water through the cold water regulating valve and the flow rate of hot water through the hot water regulating valve according to the on-site situation, so that the cold water and hot water are mixed in the flushing pipe to form flushing water with a suitable water temperature to flush the pyrolysis furnace.

[0009] The flushing pipeline of the pyrolysis furnace in the present denitration system uses hot water and cold water to form flushing water for flushing. At the same time, a temperature meter is configured and combined with a hot water regulating valve and a cold water regulating valve so that the staff can timely adjust the flow of hot water and cold water according to the on-site situation, so that the mixed flushing water is always at the best flushing temperature, thereby ensuring the best flushing effect and well solving the problem of urea spray guns and pipelines being blocked due to crystallization. Moreover, since the flue itself radiates heat outward, the flushing pipeline of the pyrolysis furnace in the present denitration system directly uses the heat radiated outward from the flue to heat the condensate. Compared with the conventional method of directly drawing a branch pipe from other hot water pipelines to supply hot water, it can not only ensure the flushing effect of the pyrolysis furnace, but also make good use of the heat radiated from the outside of the flue, reducing the heat loss of the boiler unit caused by directly drawing a branch pipe from other hot water pipelines to supply hot water.

[0010] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, the denitration system includes a denitration reactor, and the flue is a flue connected to the inlet / outlet of the denitration reactor.

[0011] The denitration reactor and the pyrolysis furnace are both equipment in the denitration system, and the distance between the two is relatively close. The hot water branch pipe 1 is connected to the outside of the flue at the inlet / outlet of the denitration reactor so that the condensed water in the hot water branch pipe 1 can be heated to hot water and then be closer to the pyrolysis furnace, that is, the transportation distance of the hot water is relatively short. This can avoid the problem of the hot water temperature decreasing due to the long time of heat exchange with the air during the transportation process due to the long transportation distance, and further reduce the heat loss while improving the flushing effect of the pyrolysis furnace.

[0012] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, an insulation layer is provided on the outside of the flue at the inlet / outlet of the denitration reactor, and the hot water branch pipe is arranged between the flue at the inlet / outlet of the denitration reactor and the insulation layer.

[0013] An insulation layer is set on the outside of the flue at the inlet / outlet of the denitrification reactor. By setting the hot water branch pipe 1 between the flue at the inlet / outlet of the denitrification reactor and the insulation layer, the heat exchange between the hot water branch pipe 1 and the outside air can be isolated, so that the condensed water heated to hot water in the hot water branch pipe 1 can maintain a higher temperature, thereby avoiding heat loss and improving the flushing effect of the pyrolysis furnace.

[0014] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, a concave cavity is provided inside the insulation layer, a part of the hot water branch pipe is located in the concave cavity and a part of the outer wall of the hot water branch pipe is in contact with the inner wall of the concave cavity.

[0015] Generally speaking, the inner wall of the insulation layer arranged outside the flue is a plane to ensure that the inner wall of the insulation layer can be in close contact with the outer wall of the flue. However, since the outer side of the flue will be irregular after the hot water branch pipe 1 is arranged outside the flue, a concave cavity is arranged inside the insulation layer, a part of the hot water branch pipe is arranged in the concave cavity, and part of the outer wall of the hot water branch pipe 1 is in close contact with the inner wall of the concave cavity, so that the insulation layer and the hot water branch pipe 1 can be in close contact to prevent the heat exchange between the hot water branch pipe 1 and the outside air, so as to improve the flushing effect of the pyrolysis furnace, and at the same time, the tight connection between the original insulation layer and the outer wall of the flue can be ensured to avoid the heat outside the flue from radiating outward.

[0016] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, the insulation layer is composed of insulation cotton.

[0017] The thermal insulation cotton has good deformability and thermal insulation properties. When the thermal insulation cotton is used to form an insulation layer wrapped around the outside of the flue, the thermal insulation cotton is in contact with the hot water branch pipe 1 and the above-mentioned cavity is naturally formed through the good deformability of the thermal insulation cotton itself, so that the thermal insulation layer and the hot water branch pipe 1 are tightly fitted together to prevent the hot water branch pipe 1 from heat exchange with the outside air to ensure the flushing effect of the pyrolysis furnace.

[0018] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitrification system, the flushing pipeline also includes a hot water branch pipe 2 arranged in parallel with the hot water branch pipe 1, and the hot water branch pipe 1 and the hot water branch pipe 2 are arranged along the outside of the same flue. The inlet of the hot water branch pipe 1 and the inlet of the hot water branch pipe 2 are both connected to a hot water pipe, and the inlet of the hot water pipe is connected to the condensate water pipe, the outlet of the hot water branch pipe 1 and the outlet of the hot water branch pipe 2 are both connected to a hot water collecting pipe, and the outlet of the hot water collecting pipe and the outlet of the cold water pipe are both connected to the flushing pipe, the thermometer is an on-site thermometer, the cold water regulating valve is arranged on the cold water pipe, and the hot water regulating valve is arranged on the hot water collecting pipe.

[0019] The inlet of the hot water branch pipe 1 and the inlet of the hot water branch pipe 2 are both connected to the hot water pipe, and the inlet of the hot water pipe is connected to the condensate pipe, which means that part of the condensate in the condensate pipe flows into the hot water pipe and is diverted from the hot water pipe to the hot water branch pipe 1 and the hot water branch pipe 2. The hot water branch pipe 2 is arranged in parallel with the hot water branch pipe 1, and the hot water branch pipe 2 and the hot water branch pipe 1 are arranged along the outside of the same flue, which means that the condensate in the hot water branch pipe 1 and the condensate in the hot water branch pipe 2 will exchange heat with the flue at the same time, which can ensure that the heat exchange process is more reasonable and uniform. The condensate in the hot water branch pipe 1 and the condensate in the hot water branch pipe 2 are heated by heat exchange and then flow into the hot water collecting pipe together, and then the hot water collecting pipe uniformly mixes the heated condensate and the room temperature condensate in the cold water pipe in the flushing pipe, thereby forming flushing water with a suitable water temperature to effectively flush the pyrolysis furnace.

[0020] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, the outside of the hot water collecting pipe and the outside of the flushing pipe are both covered with thermal insulation aluminum sheets, and a thermal insulation sleeve is provided outside the hot water regulating valve.

[0021] The outside of the hot water collecting pipe and the outside of the flushing pipe are covered with thermal insulation aluminum sheets, and an insulation sleeve is set outside the hot water regulating valve, mainly to play a role of thermal insulation. This can avoid heat exchange with the outside air, which may cause the hot water temperature in the hot water collecting pipe or the mixed water temperature in the flushing pipe to decrease, thereby ensuring the flushing effect of the pyrolysis furnace.

[0022] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, the condensate water pipe is provided with a main control valve for controlling the opening and closing of the condensate water pipe.

[0023] The main control valve is set on the condensate pipe mainly to facilitate the unit staff to exercise overall control over the activation and stop of the entire flushing pipeline, so as to avoid heat loss caused by hot water branch pipe 1 and hot water branch pipe 2 still exchanging heat with the outside of the flue when flushing is not needed.

[0024] In the flushing pipeline of the pyrolysis furnace in the above-mentioned denitration system, a self-operated pressure regulating valve, an on-site pressure gauge, a pressure relief valve and a maintenance control valve are provided on the flushing pipe.

[0025] Since the entire flushing pipeline is high above the ground, the local pressure gauge is set up mainly to facilitate the unit staff to monitor the water pressure in the flushing pipe in time. When the water pressure is too high, it can be adjusted through the self-operated pressure regulating valve to protect the equipment and avoid damage to the pyrolysis furnace equipment due to excessive flushing water pressure. At the same time, the maintenance control valve is set up to disconnect the flushing pipe from other pipelines when the flushing pipe leaks, and the flushing water in the flushing pipe can be drained by setting a pressure relief valve to facilitate maintenance by the staff.

[0026] Compared with the prior art, the flushing pipeline of the pyrolysis furnace in the denitrification system is flushed by mixing high-temperature water and condensed water. On the one hand, it avoids the crystallization of urea solution due to the low temperature of the flushing water, thereby solving the problem of blockage of the urea spray gun and the pipeline due to crystallization, and improving the flushing effect of the urea solution in the pyrolysis furnace; on the other hand, it will not cause damage to the seals or control valves due to excessively high temperature, thereby ensuring the operational stability of the denitrification system itself.

[0027] Moreover, the flushing pipeline of the pyrolysis furnace in the denitrification system directly utilizes the heat radiated outward from the flue to heat the condensate, which not only ensures the flushing effect of the pyrolysis furnace, but also makes good use of the heat radiated from the outside of the flue, reducing the heat loss of the boiler unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the flushing pipeline of the pyrolysis furnace in this denitrification system.

[0029] Figure 2 This is a schematic diagram of the distribution between the hot water branch pipe 1, the hot water branch pipe 2 and the flue in the flushing pipeline of the pyrolysis furnace in the denitrification system.

[0030] In the figure, 1. flushing pipe; 2. condensate water pipe; 3. hot water pipe; 4. cold water pipe; 5. hot water branch pipe 1; 6. hot water branch pipe 2; 7. flue; 8. insulation layer; 8a. concave cavity; 9. hot water collecting pipe; 10. main control valve; 11. hot water regulating valve; 12. cold water regulating valve; 13. thermometer; 14. self-operated pressure regulating valve; 15. local pressure gauge; 16. pressure relief valve; 17. maintenance control valve; 18. boiler auxiliary steam cooling water pipe; 19. three-way joint. DETAILED DESCRIPTION

[0031] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0032] Embodiment 1

[0033] like Figure 1 As shown, a flushing pipeline of a pyrolysis furnace in a denitration system, the denitration system includes a pyrolysis furnace, the flushing pipeline includes a cold water pipe 4, a hot water branch pipe 5, a flushing pipe 1 for flushing the pyrolysis furnace, and a condensate pipe 2 led from the boiler unit where the denitration system is located, and the condensate pipe 2 is specifically led from the boiler auxiliary steam cooling water pipe 18 in the boiler unit. The outlet of the cold water pipe 4 and the outlet of the hot water branch pipe 5 are both connected to the flushing pipe 1, and the inlet of the cold water pipe 4 and the inlet of the hot water branch pipe 5 are both connected to the condensate pipe 2. The hot water branch pipe 5 is arranged along the outer side of the flue 7 on the boiler unit where the denitration system is located. A thermometer 13 is arranged on the flushing pipe 1, and the flushing pipeline also includes a hot water regulating valve 11 capable of regulating the hot water flow and a cold water regulating valve 12 capable of regulating the cold water flow.

[0034] Specifically, the denitrification system also includes a denitrification reactor, and the flue 7 is the flue 7 at the entrance of the denitrification reactor, that is, the hot water branch pipe 5 is arranged along the outside of the flue 7 connected to the entrance of the denitrification reactor. The denitrification reactor and the pyrolysis furnace are both equipment in the denitrification system, and the distance between the two is relatively close. The hot water branch pipe 5 is arranged along the outside of the flue connected to the entrance of the denitrification reactor so that the condensed water in the hot water branch pipe 5 is closer to the pyrolysis furnace, that is, the transportation distance of the hot water is shorter, which can avoid the hot water from exchanging heat with the air for a long time due to the long transportation distance during the transportation process.

[0035] like Figure 1 and Figure 2 As shown, a heat preservation layer 8 is provided on the outside of the flue 7 at the entrance of the denitration reactor, and the hot water branch pipe 5 is provided between the flue 7 at the entrance of the denitration reactor and the heat preservation layer 8. A concave cavity 8a is provided on the inside of the heat preservation layer 8, and a part of the hot water branch pipe 5 is located in the concave cavity 8a, and a part of the outer wall of the hot water branch pipe 5 is in contact with the inner wall of the concave cavity 8a. The heat preservation layer 8 is specifically composed of heat preservation cotton. When the heat preservation layer 8 composed of heat preservation cotton is wrapped on the outside of the flue 7, the heat preservation layer 8 will contact with the hot water branch pipe 5 and naturally form a concave cavity 8a through the good deformability of the heat preservation cotton itself, so that the heat preservation layer 8 and the hot water branch pipe 5 can be closely attached together.

[0036] like Figure 1 and Figure 2As shown, the flushing pipeline also includes a hot water branch pipe 2 6, which is arranged in parallel with the hot water branch pipe 1 5, and the hot water branch pipe 1 5 and the hot water branch pipe 2 6 are arranged along the outside of the flue 7 connected to the inlet of the denitrification reactor, and the hot water branch pipe 2 6 is also arranged between the insulation layer 8 and the flue 7 at the inlet of the denitrification reactor. The inlet of the hot water branch pipe 1 5 and the inlet of the hot water branch pipe 2 6 are both connected to a hot water pipe 3, and the inlet of the cold water pipe 4 and the inlet of the hot water pipe 3 are both connected to the condensation water pipe 2, and the cold water pipe 4, the hot water pipe 3 and the condensation water pipe 2 are specifically connected by a three-way joint 19, and the outlet of the hot water branch pipe 1 5 and the outlet of the hot water branch pipe 2 6 are both connected to a hot water collecting pipe 9, and the outlet of the hot water collecting pipe 9 and the outlet of the cold water pipe 4 are both connected to the flushing pipe 1, and the hot water collecting pipe 9, the cold water pipe 4 and the flushing pipe 1 are also connected by a three-way joint 19.

[0037] like Figure 1 As shown, the condensate water pipe 2 is provided with a main control valve 10 for controlling the opening and closing of the condensate water pipe 2. Since the entire flushing pipeline is introduced by the condensate water pipe 2, the main control valve 10 is provided on the condensate water pipe 2, which can facilitate the boiler unit staff to carry out overall control of the activation and stopping of the entire flushing pipeline, thereby avoiding heat loss caused by the hot water branch pipe 5 still exchanging heat with the outside of the flue 7 when flushing is not needed.

[0038] When the pyrolysis furnace needs to be flushed, the boiler unit staff controls the main control valve 10 to open, so that the condensed water in the condensed water pipe 2 flows into the hot water pipe 3 and the cold water pipe 4 respectively. Since the hot water pipe 3 is branched into a hot water branch pipe 1 5 and a hot water branch pipe 2 6 at the flue 7 at the entrance of the denitrification reactor, and the hot water branch pipe 1 5 and the hot water branch pipe 2 6 are both arranged along the outer side of the flue 7 at the entrance of the denitrification reactor, and the flue 7 at the entrance of the denitrification reactor will radiate very high heat outward, the condensed water flowing into the hot water pipe 3 will be branched into the hot water branch pipe 1 5 and the hot water branch pipe 2 6, and the hot water branch pipe 1 5 and the hot water branch pipe 2 6 will respectively exchange heat with the high heat radiated from the outer side of the flue 7, thereby heating the condensed water flowing into the hot water branch pipe 1 5 and the condensed water flowing into the hot water branch pipe 2 6 to form hot water with a relatively high temperature. Finally, the hot water in the hot water branch pipe 1 5 and the hot water in the branch pipe 3 flow into the hot water collecting pipe 9 together, and the hot water collecting pipe 9 uniformly mixes the heated condensed water and the room temperature condensed water in the cold water pipe 4 in the flushing pipe 1, thereby forming flushing water with a suitable water temperature to effectively flush the pyrolysis furnace.

[0039] The flushing pipeline of the pyrolysis furnace in the present denitrification system utilizes a mixture of high-temperature condensed water and room-temperature condensed water to form flushing water to flush the pyrolysis furnace. On the one hand, it avoids the crystallization of urea solution due to excessive flushing water temperature, thereby solving the problem of blockage of urea spray guns and pipelines due to crystallization, and improving the flushing effect of urea solution in the pyrolysis furnace. On the other hand, since many seals or control valves are provided on the urea pipelines and urea spray guns in the pyrolysis furnace, the use of mixed flushing water will not cause damage to the seals or control valves due to excessive temperature, thereby ensuring the operational stability of the denitrification system itself. Moreover, since the flue 7 itself radiates heat outward, the flushing pipeline of the pyrolysis furnace in the present denitrification system directly utilizes the heat radiated outward by the flue 7 to heat the condensate water. Compared with the conventional method of directly supplying hot water through a branch pipe from the other three hot water pipes, it can not only ensure the flushing effect of the pyrolysis furnace, but also make good use of the heat radiated from the outside of the flue 7, reducing the heat loss of the boiler unit caused by directly supplying hot water through a branch pipe from the other three hot water pipes. At the same time, since the hot water is obtained by heat exchange, the temperature of the hot water is unstable. In this way, the temperature of the flushing water can be ensured to be always at the optimal flushing temperature by mixing cold and hot water and combining the flow rate of cold and hot water.

[0040] like Figure 1 As shown, in addition, by setting a thermometer 13 on the flushing pipe 1, the thermometer 13 is specifically an on-site thermometer, which is convenient for the unit staff to monitor the mixed water temperature of the flushing pipe 1 on the ground. At the same time, the hot water regulating valve 11 is set on the hot water collecting pipe 9, and the cold water control valve 12 is set on the cold water pipe, so that the unit staff can adjust the flow of hot water and cold water in time according to the situation on site, so that the mixed flushing water is always at the optimal flushing temperature, so as to better flush the urea solution in the pyrolysis furnace.

[0041] In addition, the outside of the hot water manifold 9 and the outside of the flushing pipe 1 are coated with thermal insulation aluminum, and a thermal insulation sleeve is provided outside the hot water regulating valve 11. The outside of the hot water manifold 9 and the outside of the flushing pipe 1 are coated with thermal insulation aluminum, and a thermal insulation sleeve is provided outside the hot water regulating valve 11, mainly for thermal insulation, so as to avoid the temperature of the hot water in the hot water manifold 9 or the temperature of the mixed flushing water in the flushing pipe 1 from decreasing due to heat exchange with the outside air, so as to ensure the flushing effect of the pyrolysis furnace.

[0042] like Figure 1As shown, the flushing pipe 1 is also provided with a self-operated pressure regulating valve 14, an on-site pressure gauge 15, a pressure relief valve 16 and a maintenance control valve 17. Since the entire flushing pipeline is relatively high from the ground, the on-site pressure gauge 15 is provided mainly to facilitate the crew to monitor the water pressure in the flushing pipe 1 in a timely manner. When the water pressure is too high, the self-operated pressure regulating valve 14 can be used to adjust it to protect the equipment and avoid damage to the pyrolysis furnace equipment due to excessive flushing water pressure. At the same time, the maintenance control valve 17 is provided to disconnect the flushing pipe 1 from other pipelines when a leak occurs in the flushing pipe 1, and the flushing water in the flushing pipe 1 can be drained by providing the pressure relief valve 16 so that the crew can conveniently perform maintenance.

[0043] Embodiment 2

[0044] The structure and principle of this embodiment are basically the same as those of the first embodiment, except that: in this embodiment, the hot water branch pipe 1 5 and the hot water branch pipe 2 6 are both arranged along the outer side of the flue 7 at the outlet of the denitration reactor.

[0045] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A flushing pipeline for a pyrolysis furnace in a denitration system, comprising a cold water pipe (4), a hot water branch pipe (5), and a flushing pipe (1) for flushing a urea solution, wherein the outlet of the cold water pipe (4) and the outlet of the hot water branch pipe (5) are both connected to the flushing pipe (1), and characterized in that: The flushing pipeline also includes a condensate pipe (2) led from the boiler unit where the denitration system is located, the inlet of the cold water pipe (4) is connected to the condensate pipe (2), the denitration system includes a denitration reactor, and the flushing pipeline also includes a hot water branch pipe (2) arranged in parallel with the hot water branch pipe (5), the hot water branch pipe (5) and the hot water branch pipe (6) are both arranged along the outside of the flue (7) connected to the inlet of the denitration reactor, and the inlet of the hot water branch pipe (5) and the inlet of the hot water branch pipe (6) are both connected to a hot water pipe (3). The hot water pipe (3) and the condensate pipe (2) are connected, and the inlet of the hot water pipe (3) is connected to the condensate pipe (2), the outlet of the hot water branch pipe 1 (5) and the outlet of the hot water branch pipe 2 (6) are both connected to a hot water collecting pipe (9), and the outlet of the hot water collecting pipe (9) and the outlet of the cold water pipe (4) are both connected to the flushing pipe (1), the hot water collecting pipe (9) is provided with a hot water regulating valve (11), the cold water pipe (4) is provided with a cold water regulating valve (12), and the flushing pipe (1) is provided with a temperature gauge (13), and the temperature gauge (13) is an on-site temperature gauge.

2. The flushing pipeline of the pyrolysis furnace in the denitration system according to claim 1, characterized in that: A heat-insulating layer (8) is provided on the outside of the flue (7) at the inlet of the denitrification reactor, and the hot water branch pipe 1 (5) is arranged between the flue (7) at the inlet of the denitrification reactor and the heat-insulating layer (8).

3. The flushing pipeline of the pyrolysis furnace in the denitration system according to claim 2, characterized in that: A concave cavity (8a) is provided on the inner side of the thermal insulation layer (8), a portion of the hot water branch pipe (5) is located in the concave cavity (8a), and a portion of the outer wall of the hot water branch pipe (5) is in contact with the inner wall of the concave cavity (8a).

4. The flushing pipeline of the pyrolysis furnace in the denitration system according to claim 3, characterized in that: The thermal insulation layer (8) is composed of thermal insulation cotton.

5. The flushing pipeline of the pyrolysis furnace in the denitration system according to claim 1, characterized in that: The outside of the hot water collecting pipe (9) and the outside of the flushing pipe (1) are both covered with thermal insulation aluminum, and a thermal insulation sleeve is provided outside the hot water regulating valve (11).

6. The flushing pipeline of the pyrolysis furnace in the denitration system according to claim 1, characterized in that: The condensate water pipe (2) is provided with a main control valve (10) for controlling the opening and closing of the condensate water pipe (2).

7. The flushing pipeline of the pyrolysis furnace in the denitration system according to claim 1, characterized in that: The flushing pipe (1) is provided with a self-operated pressure regulating valve (14), an on-site pressure gauge (15), a pressure relief valve (16) and a maintenance control valve (17).

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