Boiler drain and sootblowing drain recycling system and recycling method

Abstract

The boiler drain and sootblower drain recycling system and recycling method of the present invention belong to the field of power plant thermal system technology optimization. The system includes an atmospheric expansion tank, a steam-water separator, and a steam mixer. The present invention respectively leads the sootblower drain and the boiler heating surface drain to the steam-water separator and the atmospheric expansion tank. The drain generated by the steam-water separator is connected to the atmospheric expansion tank, and the flash steam generated by the steam-water separator is connected to the steam mixer. The steam mixer mixes the flash steam generated by the steam-water separator with the plant steam, and finally merges them into the heating main pipe for heating. The present invention can achieve effective utilization of the sootblower drain and the boiler heating surface drain. In addition, the unit that generates steam using the sootblower drain and the unit that generates steam using the boiler heating surface drain operate in parallel and can be switched at any time, thereby ensuring the reliable and stable operation of the boiler side drain to the greatest extent.

Description

Technical Field

[0001] The present invention belongs to the field of technical optimization of thermal systems of power plants, and in particular relates to a boiler drain and sootblowing drain recovery system and recovery method. Background Art

[0002] Coal-fired power plant boilers operate under complex conditions, with a significant amount of heat not being effectively utilized, resulting in energy waste. Boiler heating surface draining primarily removes condensate generated by steam during boiler startup to preheat the heating surface and prevent water hammer caused by poor drainage. Furthermore, drain valves are also required to drain condensate generated by steam at some point after shutdown. Fully opening the superheater drain valve during boiler startup can also shorten the time the steam reaches temperature, thereby reducing startup time. Power plant boilers also require extensive daily soot blowing to prevent coking on the heating surfaces, and the drain generated during this process also contains a significant amount of heat.

[0003] Therefore, it is of great significance to improve the energy utilization in the drainage of power station boilers and enhance the utilization rate of energy and working fluid of power station boilers. Summary of the Invention

[0004] The object of the present invention is to provide a boiler drain and sootblower drain recovery system and recovery method to solve the above technical problems.

[0005] To this end, the present invention provides a boiler drain and sootblowing drain recovery and utilization system, comprising:

[0006] Atmospheric expansion tank, the inlet of which is connected to the sootblowing drain main pipe and the boiler heating surface drain main pipe respectively;

[0007] A steam-water separator, the water inlet of which is connected to the sootblowing drain main pipe and the boiler heating surface drain main pipe respectively, and the water outlet of the steam-water separator is connected to the atmospheric expansion tank;

[0008] A steam mixer, one inlet of which is connected to the flash steam outlet of the steam-water separator through a flash steam pipe, on which a flow meter and a manual shut-off valve are installed, and another inlet of the steam mixer is connected to the plant steam pipe; the outlet of the steam mixer is connected to the heating main pipe.

[0009] The present invention directs the sootblowing drain and boiler heating surface drain to a steam separator and an atmospheric expansion tank, respectively. The drain generated by the steam separator is connected to the atmospheric expansion tank, and the flash steam generated by the steam separator is connected to a steam mixer. The steam mixer mixes the flash steam generated by the steam separator with plant steam, and finally flows into the heating main pipe for heat supply. This invention effectively utilizes the sootblowing drain and the boiler heating surface drain. The units that generate steam using the sootblowing drain and the units that generate steam using the boiler heating surface drain operate in parallel and can be switched at any time, ensuring the reliable and stable operation of the boiler-side drain to the greatest extent possible.

[0010] Preferably, the outlet of the atmospheric expander is connected to an expander exhaust pipe, and the pressure relief port of the steam-water separator is in communication with the expander exhaust pipe.

[0011] Atmospheric expansion tanks are used to reduce the pressure of hydrophobic expansion tanks. After expansion, steam enters the expansion tank exhaust pipe, reducing the heat load and impact on the atmospheric expansion tank. Some steam in the steam separator is discharged through the pressure relief port to prevent excessive pressure in the steam separator and damage to the equipment.

[0012] Preferably, the flash steam pipeline is also connected to a bypass regulating pipeline, which is connected to the pipeline between the pressure relief port and the exhaust pipeline of the expansion tank, and the bypass regulating pipeline is installed with a remote temperature transmitter, a remote pressure transmitter, an electric shut-off valve and an electric regulating valve.

[0013] When the temperature of the heating main pipe is lower than the limit value, the electric shut-off valve is fully opened or the electric regulating valve is adjusted to a larger value, and part of the steam in the steam-water separator is discharged into the exhaust pipe of the expansion tank, reducing the flash steam flow connected to the steam mixer and increasing the temperature of the heating main pipe.

[0014] Preferably, the sootblowing drain main pipe and the boiler heating surface drain main pipe are respectively provided with a first tee joint and a second tee joint, the water inlet of the steam-water separator is respectively connected to the first tee joint and the second tee joint, and electric shut-off valves are installed on the pipeline between the first tee joint and the water inlet of the steam-water separator, the pipeline between the first tee joint and the inlet of the atmospheric expansion tank, the pipeline between the second tee joint and the water inlet of the steam-water separator, and the pipeline between the second tee joint and the inlet of the atmospheric expansion tank.

[0015] A first tee is installed on the sootblower drain main pipe, connecting one sootblower drain to the atmospheric expansion vessel and the other to the steam-water separator. Similarly, a second tee is installed on the boiler heating surface drain main pipe, connecting one boiler heating surface drain to the atmospheric expansion vessel and the other to the steam-water separator. Electric shutoff valves are installed to enable parallel operation of the atmospheric expansion vessel and steam-water separator, allowing for switching between them at any time, ensuring the maximum reliable and stable operation of the boiler-side drains.

[0016] Preferably, the flash steam pipeline is also equipped with a remote temperature transmitter, a remote pressure transmitter, an electric regulating valve and a check valve.

[0017] Remote temperature transmitters and remote pressure transmitters monitor the temperature and pressure in the flash steam pipeline at any time. The electric control valve adjusts the opening according to the temperature and pressure in the flash steam pipeline. The check valve ensures that the steam in the pipeline flows in one direction, preventing the steam in the pipeline from flowing back into the steam-water separator, thereby ensuring equipment safety.

[0018] Preferably, a drain pipe is also installed on the flash steam pipeline, and the drain pipe includes a first main drain pipe and a first bypass drain pipe arranged in parallel, the first main drain pipe is installed with a manual stop valve, and the first bypass drain pipe is installed with an automatic drain trap and a manual stop valve.

[0019] Preferably, an on-site liquid level gauge is installed on the steam-water separator, and an electric regulating valve is installed on the pipeline between the on-site liquid level gauge and the steam-water separator. The pipeline between the water outlet of the steam-water separator and the atmospheric expansion tank includes a second main water drain pipe and a second bypass water drain pipe arranged in parallel. An automatic water trap and a manual stop valve are installed on the second main water drain pipe, and an electric stop valve is installed on the second bypass water drain pipe.

[0020] The main and bypass drains of the steam-water separator operate in parallel. The automatic trap installed on the second main drain discharge pipe is used during normal operation. It opens when the liquid level exceeds the warning level and closes when the liquid level falls below the minimum level. The electric shut-off valve installed on the second bypass drain discharge pipe serves as an emergency drain valve.

[0021] Preferably, the steam-water separator is also equipped with an on-site pressure gauge, a remote pressure transmitter and an on-site temperature gauge.

[0022] The local pressure display indicates the pressure, the remote pressure transmitter detects the pressure in the steam-water separator and transmits it to the control system, and the local temperature display indicates the temperature.

[0023] In addition, the present invention provides a boiler drain and sootblowing drain recovery and utilization method, which is implemented using the boiler drain and sootblowing drain recovery and utilization system as described above, and includes the following steps:

[0024] S1. Before starting the system, check and confirm that the valves on the steam-water separator, steam mixer and the pipelines connecting the equipment are operating normally and that all valves are in the closed state;

[0025] S2. Gradually slightly open the valves on the pipelines to drain and warm the pipelines. After draining all the water in the pipeline chambers, close the valves on the sootblowing drain main pipe and the boiler heating surface drain main pipe, and open the valves on the remaining pipelines.

[0026] S3. Check and confirm that the steam-water separator, steam mixer, and valves on the connecting pipes between the equipment are operating normally, the equipment temperature and pressure are stable, and the system is operating stably;

[0027] S4. When shutting down the system, first close the valves on the pipes between the sootblowing drain main pipe and the steam-water separator, and the valves on the pipes between the boiler heating surface drain main pipe and the steam-water separator, and open the valves on the pipes between the sootblowing drain main pipe and the atmospheric expansion tank, and the valves on the pipes between the boiler heating surface drain main pipe and the atmospheric expansion tank to drain all the drain.

[0028] Preferably, between S3 and S4, when the temperature of the heating main pipe is lower than the set value, the bypass regulating pipe is opened or the flash steam flow connected to the steam mixer is reduced; when the temperature of the heating main pipe is higher than the set value, the bypass regulating pipe is closed or the flash steam flow connected to the steam mixer is increased.

[0029] Compared with the prior art, the characteristics and beneficial effects of the present invention are:

[0030] (1) The present invention leads the sootblowing drain and boiler heating surface drain to the steam-water separator and the atmospheric expansion tank respectively. The drain generated by the steam-water separator is connected to the atmospheric expansion tank, and the flash steam generated by the steam-water separator is connected to the steam mixer. The steam mixer mixes the flash steam generated by the steam-water separator with the plant steam, and finally flows into the heating main pipe for heating. The present invention can achieve effective utilization of the sootblowing drain and the boiler heating surface drain. In addition, the unit that generates steam by sootblowing drain and the unit that generates steam by boiler heating surface drain operate in parallel and can be switched at any time, thereby ensuring the reliable and stable operation of the boiler side drain to the greatest extent.

[0031] (2) In the present invention, the steam-water separator receives two drains, and the sootblowing drain and the boiler heating surface drain have different temperatures and pressures. When the temperature in the steam-water separator does not reach the set value, the inflow of the sootblowing drain and the boiler heating surface drain is adjusted to make the temperature in the steam-water separator reach the set value. In addition, the steam mixer mixes the flash steam generated by the steam-water separator with the plant steam. When the temperature of the heating main pipe is lower than the set value, the flash steam flow rate connected to the steam mixer is reduced to increase the temperature of the heating main pipe. When the temperature of the heating main pipe is higher than the set value, the flash steam flow rate connected to the steam mixer is increased to reduce the temperature of the heating main pipe. The heating temperature can be flexibly adjusted by temperature matching.

[0032] (3) The hydrophobic recycling system of the present invention utilizes liquid pressure difference or gas pressure difference to move the liquid or gas in a set direction, and does not require water pump equipment, thereby reducing equipment energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the boiler drain and sootblower drain recovery system;

[0034] Figure 2 for Figure 1 A magnified schematic diagram of part A;

[0035] Figure 3 for Figure 1 A magnified schematic diagram of part B;

[0036] Figure 4 for Figure 1 The enlarged schematic diagram of part C in the middle;

[0037] Figure 5 for Figure 1 The enlarged schematic diagram of part D in the middle;

[0038] Figure 6 for Figure 1 Enlarged schematic diagram of part E in the middle.

[0039] Figure markings: 1-sootblowing drain main pipe, 2-boiler heating surface drain main pipe, 3-atmospheric expansion tank, 4-steam-water separator, 5-steam mixer, 6-first three-way joint, 7-second three-way joint, 8-flash steam pipeline, 9-plant area steam pipeline, 10-heating main pipe, 11-flow meter, 12-manual shut-off valve, 13-expansion tank exhaust pipe, 14-flash steam outlet, 15-pressure relief port, 16-bypass regulating pipe, 17 -Remote temperature transmitter, 18-Remote pressure transmitter, 19-Electric regulating valve, 20-Check valve, 21-First main drain pipe, 22-First bypass drain pipe, 23-Manual stop valve, 24-Automatic drain trap, 25-Electric stop valve, 26-Electric shut-off valve, 27-Local pressure gauge, 28-Local temperature gauge, 29-Local liquid level gauge, 30-Second main drain pipe, 31-Second bypass drain pipe. DETAILED DESCRIPTION

[0040] In order to make the technical means, innovative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below.

[0041] The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention. They are illustrative and exemplary and should not be construed as limiting the embodiments and scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the claims and the disclosure of the specification, including technical solutions that adopt any obvious substitutions and modifications to the embodiments described herein.

[0042] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0044] like Figure 1-6 The figure shows a boiler drain and sootblower drain recovery system, which includes an atmospheric expansion tank 3, a steam-water separator 4 and a steam mixer 5.

[0045] The inlet of the atmospheric expander 3 is connected to the sootblowing drain main pipe 1 and the boiler heating surface drain main pipe 2, respectively. The outlet of the atmospheric expander 3 is connected to the expander exhaust pipe 13, and the pressure relief port 15 of the steam-water separator 4 is connected to the expander exhaust pipe 13. The sootblowing drain main pipe 1 and the boiler heating surface drain main pipe 2 are respectively equipped with a first tee 6 and a second tee 7. The water inlet of the steam-water separator 4 is connected to the first tee 6 and the second tee 7, respectively. Electric shut-off valves 26 are installed on the pipeline between the first tee 6 and the water inlet of the steam-water separator 4, the pipeline between the first tee 6 and the inlet of the atmospheric expander 3, the pipeline between the second tee 7 and the water inlet of the steam-water separator 4, and the pipeline between the second tee 7 and the inlet of the atmospheric expander 3. After passing through the first tee 6, the sootblowing drain is connected to the atmospheric expander 3 on one side and the steam-water separator 4 on the other side. After the boiler heating surface drain passes through the second three-way joint 7, one drain is connected to the atmospheric expansion tank 3, and the other drain enters the steam-water separator 4.

[0046] The water inlet of the steam-water separator 4 is connected to the sootblowing drain main pipe 1 and the boiler heating surface drain main pipe 2, respectively. The water outlet of the steam-water separator 4 is connected to the atmospheric expansion vessel 3. A local level gauge 29 is installed on the steam-water separator 4. An electric regulating valve 19 is installed on the pipeline between the local level gauge 29 and the steam-water separator 4. The pipeline between the water outlet of the steam-water separator 4 and the atmospheric expansion vessel 3 includes a second main drain pipe 30 and a second bypass drain pipe 31, which are arranged in parallel. The second main drain pipe 30 is equipped with an automatic drain trap 24 and a manual shut-off valve 23. The second bypass drain pipe 31 is equipped with an electric shut-off valve 25. The main and bypass drains of the steam-water separator 4 operate in parallel. The automatic drain trap 24, installed on the second main drain pipe 30, is used during normal operation. It opens when the liquid level exceeds the warning level and closes when the liquid level falls below the minimum level. The electric shut-off valve 25 installed on the second bypass drain pipe 31 serves as an emergency drain valve.

[0047] The separator 4 is also equipped with a local pressure gauge 27, a remote pressure transmitter 18, and a local temperature gauge 28. The local pressure gauge 27 is used to indicate the pressure in the separator 4 on site, the remote pressure transmitter 18 detects the pressure in the separator 4 and transmits it to the control system, and the local temperature gauge 28 indicates the temperature on site.

[0048] One inlet of the steam mixer 5 is connected to the flash steam outlet 14 of the steam-water separator 4 via a flash steam pipe 8, which is equipped with a flow meter 11 and a manual shut-off valve 12. The other inlet of the steam mixer 5 is connected to the plant steam pipe 9. The outlet of the steam mixer 5 is connected to the heating main pipe 10. The steam mixer 5 mixes the flash steam from the steam-water separator 4 with the plant steam and then flows it into the heating main pipe 10 for heating.

[0049] The flash steam pipeline 8 is also equipped with a remote temperature transmitter 17, a remote pressure transmitter 18, an electric control valve 19, and a check valve 20. The remote temperature transmitter 17 monitors the steam temperature in the flash steam pipeline 8 and transmits the temperature signal to the control system. The remote pressure transmitter 18 monitors the steam pressure in the flash steam pipeline 8 and transmits the pressure signal to the control system. The control system controls the electric control valve 19 to adjust the valve opening based on the temperature and pressure in the flash steam pipeline 8. The check valve 20 ensures one-way steam flow in the pipeline, preventing steam from flowing back into the steam-water separator and ensuring equipment safety.

[0050] A drain pipe is also installed on the flash steam pipeline 8, which includes a first main drain pipe 21 and a first bypass drain pipe 22 arranged in parallel. A manual stop valve 23 is installed on the first main drain pipe 21, and an automatic drain valve 24 and a manual stop valve 23 are installed on the first bypass drain pipe 22.

[0051] The flash steam pipeline 8 is also connected to a bypass regulating pipeline 16, which communicates with the pipeline between the pressure relief port 15 and the expander exhaust pipeline 13. The bypass regulating pipeline 16 is equipped with a remote temperature transmitter 17, a remote pressure transmitter 18, an electric shutoff valve 26, and an electric regulating valve 19. When the steam temperature in the heating main pipe 10 is lower than the set value, the electric shutoff valve 26 is fully opened or the electric regulating valve 19 is opened more widely, increasing the amount of steam entering the expander exhaust pipeline 13 and reducing the amount of flash steam entering the steam mixer 5, thereby raising the steam temperature in the heating main pipe 10. When the steam temperature in the heating main pipe 10 is higher than the set value, the electric shutoff valve 26 is fully closed or the electric regulating valve 19 is opened more widely, reducing the amount of steam entering the expander exhaust pipeline 13 and increasing the amount of flash steam entering the steam mixer 5, thereby lowering the steam temperature in the heating main pipe 10.

[0052] A boiler drain and sootblower drain recovery and utilization method is implemented using the above-mentioned boiler drain and sootblower drain recovery and utilization system, comprising the following steps:

[0053] S1. Before starting the system, check and confirm that the valves on the steam-water separator 4, steam mixer 5 and the pipelines connecting various devices in the system are operating normally, and confirm that all valves are in the closed state.

[0054] S2. Gradually slightly open the valves on the pipeline to drain and warm the pipeline. Slightly opening means 2%-5% of the total stroke of each valve. After the accumulated water in the pipeline cavity is drained, the manual stop valve 23 on the first main drain discharge pipe 21, the electric stop valve 26 on the sootblower drain main pipe 1 and the boiler heating surface drain main pipe 2, the electric stop valve 25 between the water outlet of the steam-water separator 4 and the atmospheric expansion tank 3, the electric control valve 19, the check valve 20 and the electric stop valve 26 on the bypass regulating pipe 16 are all closed, and the valves on the remaining pipelines are opened.

[0055] S3. During normal operation, the manual stop valve 23 on the first main drain pipe 21 is closed, the manual stop valve 23 on the first bypass drain pipe 22 is opened, the electric stop valves 26 on the sootblower drain main pipe 1 and the boiler heating surface drain main pipe 2 are closed, the electric stop valve 25 between the water outlet of the steam-water separator 4 and the atmospheric expansion tank 3 is closed, the electric regulating valve 19, the check valve 20 and the electric stop valve 26 on the bypass regulating pipe 16 are all closed, and the valves on other pipes are opened.

[0056] S4. Check and confirm that the steam-water separator 4, steam mixer 5 and valves on the connecting pipes between various devices in the system are operating normally, the temperature and pressure of various devices in the system are stable, and the system operation is stable.

[0057] S5. The drain of the steam-water separator 4 is connected to the atmospheric expansion tank 3. The interface is located above the liquid level in the boiler drain tank. During normal operation, the automatic steam trap 24 of the second main drain discharge pipe 30 is activated. When the liquid level of the steam-water separator 4 exceeds the warning level, the electric stop valve 25 of the second bypass drain discharge pipe 31 opens. When the liquid level reaches the normal level, the electric stop valve 25 closes.

[0058] S6. When the temperature of the heating main pipe 10 is lower than the set value, the electric regulating valve 19, the check valve 20 and the electric shut-off valve 26 on the bypass regulating pipe 16 are closed, or the check valve 20 and the electric shut-off valve 26 are opened while the opening of the electric regulating valve 19 is reduced; when the temperature of the heating main pipe 10 is higher than the set value, the electric regulating valve 19, the check valve 20 and the electric shut-off valve 26 on the bypass regulating pipe 16 are fully opened, or the check valve 20 and the electric shut-off valve 26 on the bypass regulating pipe 16 are opened while the opening of the electric regulating valve 19 is increased.

[0059] S7. When shutting down the system, first close the electric shut-off valve 26 from the sootblowing drain main pipe 1 to the steam-water separator 4 and the electric shut-off valve 26 from the boiler heating surface drain main pipe 2 to the steam-water separator 4, open the electric shut-off valve 26 from the sootblowing drain main pipe 1 to the atmospheric expansion tank 3 and the electric shut-off valve 26 from the boiler heating surface drain main pipe 2 to the atmospheric expansion tank 3, open the manual shut-off valve 23 and the automatic steam trap 24 on the first main drain discharge pipe 21, close the manual shut-off valve 23 on the first bypass drain discharge pipe 22, and after all the drain is drained, close the manual shut-off valve 12, the electric regulating valve 19 and the electric shut-off valve 26 on the flash steam pipe 8.

[0060] The above embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A boiler drain and sootblower drain recovery system, characterized in that include: An atmospheric expansion container (3), the inlet of which is respectively connected to the sootblowing drain main pipe (1) and the boiler heating surface drain main pipe (2); A steam-water separator (4), the water inlet of which is respectively connected to the sootblowing drain main pipe (1) and the boiler heating surface drain main pipe (2), and the water outlet of the steam-water separator (4) is connected to the atmospheric expansion tank (3); A steam mixer (5) has one inlet connected to a flash steam outlet (14) of a steam-water separator (4) via a flash steam pipe (8), wherein a flow meter (11) and a manual shut-off valve (12) are installed on the flash steam pipe (8). Another inlet of the steam mixer (5) is connected to a plant steam pipe (9); the outlet of the steam mixer (5) is connected to a heating main pipe (10); and a bypass regulating pipe (16) is also connected to the flash steam pipe (8).

2. The boiler drain and sootblower drain recovery and utilization system according to claim 1, characterized in that: The outlet of the atmospheric expander (3) is connected to the expander exhaust pipe (13), and the pressure relief port (15) of the steam-water separator (4) is connected to the expander exhaust pipe (13); the sootblowing drain main pipe (1) and the boiler heating surface drain main pipe (2) are respectively provided with a first three-way joint (6) and a second three-way joint (7), and the water inlet of the steam-water separator (4) is respectively connected to the first three-way joint (6) and the second three-way joint (7).

3. The boiler drain and sootblower drain recovery and utilization system according to claim 2, characterized in that: The bypass regulating pipe (16) is connected to a pipe between the pressure relief port (15) and the expansion tank exhaust pipe (13), and a remote temperature transmitter (17), a remote pressure transmitter (18), an electric shut-off valve (26), and an electric regulating valve (19) are installed on the bypass regulating pipe (16).

4. The boiler drain and sootblower drain recovery and utilization system according to claim 2, characterized in that: Electric shut-off valves (26) are installed on the pipeline between the first three-way joint (6) and the water inlet of the steam-water separator (4), the pipeline between the first three-way joint (6) and the inlet of the atmospheric expansion container (3), the pipeline between the second three-way joint (7) and the water inlet of the steam-water separator (4), and the pipeline between the second three-way joint (7) and the inlet of the atmospheric expansion container (3).

5. The boiler drain and sootblower drain recovery and utilization system according to claim 1, characterized in that: The flash steam pipeline (8) is also equipped with a remote temperature transmitter (17), a remote pressure transmitter (18), an electric regulating valve (19) and a check valve (20).

6. The boiler drain and sootblower drain recovery and utilization system according to claim 1, characterized in that: The flash steam pipeline (8) is also provided with a drain pipe, which comprises a first main drain pipe (21) and a first bypass drain pipe (22) arranged in parallel. The first main drain pipe (21) is provided with a manual stop valve (23), and the first bypass drain pipe (22) is provided with an automatic drain trap (24) and a manual stop valve (23).

7. The boiler drain and sootblower drain recovery and utilization system according to claim 1, characterized in that: The steam-water separator (4) is equipped with an on-site liquid level gauge (29). The pipeline between the water outlet of the steam-water separator (4) and the atmospheric expansion tank (3) comprises a second main drain pipe (30) and a second bypass drain pipe (31) arranged in parallel. The second main drain pipe (30) is equipped with an automatic drain valve (24) and a manual stop valve (23). The second bypass drain pipe (31) is equipped with an electric stop valve (25).

8. The boiler drain and sootblower drain recovery and utilization system according to claim 1, characterized in that: The steam-water separator (4) is also equipped with an on-site pressure gauge (27), a remote pressure transmitter (18) and an on-site temperature gauge (28).

9. A method for recycling boiler drain and sootblower drain, characterized by: The method is implemented by using the boiler drain and sootblowing drain recovery system according to any one of claims 1 to 8, comprising the following steps: S1. Before starting the system, check and confirm that the steam-water separator (4), steam mixer (5) and valves on the pipes connecting the various devices in the system are operating normally, and confirm that all valves are in the closed state; S2. Gradually slightly open the valves on the pipelines to drain and warm the pipelines. After draining the water in the pipeline chamber, close the valves on the sootblowing drain main pipe (1) and the boiler heating surface drain main pipe (2), and open the valves on the remaining pipelines. S3. Check and confirm that the steam-water separator (4), the steam mixer (5) and the valves on the pipes connecting the various devices in the system are operating normally, the temperature and pressure of the various devices in the system are stable, and the system is operating stably; S4. When shutting down the system, first close the valves on the pipe between the sootblowing drain main pipe (1) and the steam-water separator (4), and the valves on the pipe between the boiler heating surface drain main pipe (2) and the steam-water separator (4), and open the valves on the pipe between the sootblowing drain main pipe (1) and the atmospheric expansion tank (3), and the valves on the pipe between the boiler heating surface drain main pipe (2) and the atmospheric expansion tank (3) to drain the drain.

10. The boiler drain and sootblower drain recycling method according to claim 9, characterized in that: Between S3 and S4, when the temperature of the heating main pipe (10) is lower than the set value, the bypass regulating pipe (16) is opened or the flash steam flow rate connected to the steam mixer (5) is reduced; when the temperature of the heating main pipe (10) is higher than the set value, the bypass regulating pipe (16) is closed or the flash steam flow rate connected to the steam mixer (5) is increased.

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