Superheater steam-water pipeline suitable for ultrahigh-temperature flue gas condition

Abstract

The invention relates to a superheater steam-water pipeline suitable for an ultrahigh-temperature flue gas condition, and belongs to the technical field of boiler equipment. The system comprises a first-stage superheater, a second-stage superheater and a third-stage superheater which are arranged on a flue, an inlet of the first-stage superheater is connected with an upstream steam pipeline, an outlet of the first-stage superheater is connected with an inlet of the second-stage superheater through a connecting pipe, an outlet of the second-stage superheater is connected with the third-stage superheater through a downstream steam pipeline, and the connecting pipe is communicated with a drainage pipeline. The drainage pipeline is communicated with the downstream steam pipeline through a drainage bypass, and the drainage bypass is provided with a stop valve. According to the invention, the technical problem of over-temperature pipe explosion of the drainage pipeline under the condition of ultra-high-temperature flue gas is solved, and effective support is provided for gas turbine expansion. The system has the advantages of simple and reasonable pipeline, simple control logic, reliable operation and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a superheater, in particular to a superheater steam-water pipeline suitable for ultra-high temperature flue gas conditions, and belongs to the technical field of boiler equipment. BACKGROUND

[0002] The superheater tube panels of different levels of the waste heat boiler are connected through the connecting pipes in the furnace, and the bottom connecting pipe is connected with the drain pipe. When the waste heat boiler is in normal operation, the drain pipe does not drain, at this time, there is no medium flowing in the drain pipe, and the furnace pipe section of the drain pipe is in the high temperature flue gas. In order to avoid the over-temperature explosion of the drain pipe wall, the design temperature of the drain pipe should match the flue gas temperature. With the continuous increase of the capacity requirement of the gas turbine, the exhaust gas temperature of the gas turbine is also continuously increased. Especially for the combined cycle unit in the Middle East and other regions, it often has a supplementary combustion system. After the supplementary combustion, the flue gas temperature is further increased compared with the exhaust gas of the gas turbine, and even can be as high as 800 DEG C or above. However, the existing drain pipe is restricted by the pipe material and type, and the design temperature of the pipe is usually below 650 DEG C, which cannot meet the ultra-high temperature flue gas condition of 800 DEG C or above. When in operation, the over-temperature explosion of the drain pipe will inevitably occur, which will endanger the safe operation of the superheater steam-water pipeline and the unit. SUMMARY

[0003] The present application mainly solves the technical problem of over-temperature explosion of the drain pipe under the ultra-high temperature flue gas condition in the prior art, and provides a superheater steam-water pipeline suitable for ultra-high temperature flue gas conditions.

[0004] The present application mainly solves the above technical problems through the following technical scheme: the present application comprises a first superheater, a second superheater and a third superheater arranged in a flue. The inlet of the first superheater is connected with an upstream steam pipe, the outlet of the first superheater is connected with the inlet of the second superheater through a connecting pipe, the outlet of the second superheater is connected with the third superheater through a downstream steam pipe, the connecting pipe is connected with a drain pipe, the drain pipe passes through the furnace bottom plate and is provided with a drain valve at the furnace outer pipe section. The present application further comprises a drain bypass, the drain bypass is connected with the drain pipe at a bypass connection point, the bypass connection point is located at the furnace outer pipe section of the drain pipe and is located at the upstream position of the drain valve, the drain pipe is connected with the downstream steam pipe through the drain bypass, and the drain bypass is provided with a stop valve.

[0005] Preferably, the pipe section of the drain pipe located in the furnace is wrapped with high-temperature resistant insulation material.

[0006] Preferably, the pipe section of the drain pipe located in the furnace is provided with a temperature detector for monitoring the wall temperature of the drain pipe.

[0007] Preferably, the pipe section of the drain pipe located outside the furnace is provided with a drain stop valve, and the drain stop valve is arranged between the bypass connection point and the drain valve.

[0008] Preferably, the stop valve is an electric valve and is connected to the central processor of the waste heat boiler.

[0009] Preferably, the drain stop valve is an electric valve and is connected to the central processor of the waste heat boiler.

[0010] Preferably, the temperature measuring instrument is connected to the central processor of the waste heat boiler.

[0011] The present application has the advantages of simple structure, reasonable configuration and the following advantages. In the present application, a drain bypass is arranged in the drain pipeline, and the drain pipeline is connected to the downstream steam pipeline through the drain bypass. In the case that the drain pipeline does not drain under normal operation of the boiler, the medium in the drain pipeline can flow to the downstream steam pipeline through the drain bypass, and the medium continuously flowing in the pipeline exchanges heat with flue gas to reduce the drain pipeline wall temperature, so that the drain pipeline can meet the super-high temperature flue gas condition and avoid the risk of over-temperature pipe explosion.

[0012] Further, the in-furnace pipeline section of the drain pipeline is wrapped with heat insulation material to reduce the heat transfer between the flue gas and the drain pipeline and ensure that the drain pipeline wall temperature is within a safe range.

[0013] Further, the temperature measuring instrument is used to monitor the drain pipeline wall temperature, and when the drain pipeline wall temperature is higher than the design temperature of the connecting pipeline, the drain pipeline wall temperature can be reduced by increasing the flow of the drain bypass.

[0014] Further, the stop valve and the drain stop valve are electric valves, and the opening degree of the valves can be accurately controlled through the central processor of the waste heat boiler according to the monitoring data of the temperature measuring instrument.

[0015] Therefore, the present application can realize normal operation of the superheater steam-water pipeline under super-high temperature flue gas conditions and avoid over-temperature pipe explosion of the drain pipeline. The present application also has the advantages of simple and reasonable pipeline, simple control logic and reliable operation. BRIEF DESCRIPTION OF DRAWINGS

[0016] FIG. 1 is a schematic diagram of a preferred embodiment of the present application. Figure 1

[0017] Reference signs: 1. primary superheater; 2. secondary superheater; 3. tertiary superheater; 4. connecting pipeline; 5. downstream steam pipeline; 6. drain pipeline; 7. drain valve; 8. drain stop valve; 9. drain bypass; 10. stop valve; 11. temperature measuring instrument; 12. bypass connection point. DETAILED DESCRIPTION

[0018] The technical solutions of the present application will be further described below by examples in combination with the drawings.

[0019] Example 1: as shown in FIG. 1, a primary superheater 1, a secondary superheater 2, a tertiary superheater 3, a connecting pipeline 4, a downstream steam pipeline 5, a drain pipeline 6, a drain valve 7, a drain stop valve 8, a drain bypass 9, a stop valve 10, a temperature measuring instrument 11 and a bypass connection point 12 are arranged in sequence. Figure 1 ​As shown, the present application comprises a first superheater 1, a second superheater 2, and a third superheater 3 arranged in the flue. The first superheater 1 is connected to the upstream steam pipe, the outlet of the first superheater 1 is connected to the inlet of the second superheater 2 through a connecting pipe 4, the outlet of the second superheater 2 is connected to the third superheater 3 through a downstream steam pipe 5, the connecting pipe 4 is connected to a drain pipe 6, the drain pipe 6 is connected to the downstream steam pipe 5 through a drain bypass 9, and the drain bypass 9 is provided with a stop valve 10; The drain pipe 6 passes through the furnace bottom plate and is provided with a drain stop valve 8 and a drain valve 7 in the furnace outer pipe section. The drain pipe 6 is connected to the drain bypass 9 at a bypass connection point 12 located in the furnace outer pipe section of the drain pipe 6 and upstream of the drain valve 7 and the stop valve 8. The pipe section of the drain pipe 6 located in the furnace is wrapped with high-temperature-resistant insulation material and is provided with a temperature measuring instrument 11 for monitoring the drain pipe wall temperature. The drain stop valve 8 and the stop valve 10 are electric valves connected to the waste heat boiler central processor. The temperature measuring instrument 11 is connected to the waste heat boiler central processor.

[0020] When the waste heat boiler is shut down and the superheater tube panel needs to be drained, the drain stop valve 8 and the drain valve 7 are opened, and the stop valve 10 of the drain bypass 9 is closed. At this time, the drain pipe 6 normally drains through the drain valve 7. When the waste heat boiler is normally running, the drain stop valve 8 and the drain valve 7 are closed, the stop valve 10 of the drain bypass 9 is opened, and the opening degree of the stop valve 10 is controlled. The working medium flowing into the drain pipe 6 through the connecting pipe 4 flows to the downstream steam pipe 5 through the drain bypass 9, and the working medium flowing in the drain pipe exchanges heat with the flue gas. The wall temperature of the furnace inner pipe section of the drain pipe 6 is monitored by the temperature measuring instrument 11. When the drain pipe wall temperature is lower than the design temperature of the connecting pipe 4, the opening degree of the stop valve 10 is maintained. When the drain pipe wall temperature is higher than the design temperature of the connecting pipe 4, the opening degree of the stop valve 10 is increased to increase the flow of the working medium in the drain bypass 9, and the drain pipe wall temperature is reduced by increasing the flow of the drain bypass 9.

[0021] In the case where the flue gas temperature reaches 800℃ or above, the drain pipe wall temperature can be controlled below 650℃ by controlling the flow of the drain bypass 9.

[0022] Of course, the above drawings and examples are only for explanation and illustration of the present application and cannot be regarded as improper limitation of the present application. Any technical solution obtained by equivalent adjustment and change according to the present application by those skilled in the art falls within the protection scope of the present application.

Claims

1. A superheater steam piping suitable for ultra-high temperature flue gas conditions, comprising a first stage superheater (1), a second stage superheater (2), a third stage superheater (3) arranged in a flue, the first stage superheater (1) inlet is connected with an upstream steam pipe, the first stage superheater (1) outlet is connected with the second stage superheater (2) inlet through a connection pipe (4), the second stage superheater (2) outlet is connected with the third stage superheater (3) through a downstream steam pipe (5), the connection pipe (4) is communicated with a drain pipe (6), the drain pipe (6) passes through a furnace bottom plate and a drain valve (8) is arranged in an external pipe section of the furnace, characterized in that, A hydrophobic bypass (9) is further included, which is connected with the hydrophobic pipeline (6) at a bypass connection point (12) located at the out-of-furnace pipeline section of the hydrophobic pipeline (6) and upstream of the hydrophobic valve (8), and the hydrophobic pipeline (6) is communicated with the downstream steam pipeline (5) through the hydrophobic bypass (9), and the hydrophobic bypass (9) is provided with a stop valve (10).

2. A superheater water line suitable for ultra-high temperature flue gas conditions according to claim 1, characterized in that, The in-furnace pipeline section of the hydrophobic pipeline (6) is wrapped with high-temperature-resistant insulation material.

3. A superheater steam piping suitable for ultra-high temperature flue gas conditions according to claim 1 or 2, characterized in that, The in-furnace pipeline section of the hydrophobic pipeline (6) is provided with a temperature detector (11) for monitoring the temperature of the hydrophobic pipeline wall.

4. A superheater water line suitable for ultra-high temperature flue gas conditions according to claim 1 or 2, characterized in that, The out-of-furnace pipeline section of the hydrophobic pipeline (6) is provided with a hydrophobic stop valve (7) arranged between the bypass connection point (12) and the hydrophobic valve (8).

5. A superheater water line suitable for ultra-high temperature flue gas conditions according to claim 1 or 2, characterized in that, The stop valve (10) is an electric valve and is connected with a central processor of the waste heat boiler.

6. A superheater water line suitable for ultra-high temperature flue gas conditions according to claim 3, wherein, The hydrophobic stop valve (7) is an electric valve and is connected with the central processor of the waste heat boiler.

7. A superheater water line suitable for ultra-high temperature flue gas conditions according to claim 3, wherein, The temperature detector (11) is connected with the central processor of the waste heat boiler.

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