Adjustable double-flow water-cooled wall system, once-through boiler and generator set

Abstract

The invention relates to an adjustable double-flow water-cooled wall system, a once-through boiler and a generator set, the water-cooled wall system comprises a hearth water-cooled wall, an economizer and a shunting water-cooled wall device, and the shunting water-cooled wall device is provided with a shunting water-cooled wall inlet header and a shunting water-cooled wall outlet header; the shunt water-cooled wall inlet header is connected with a shunt water-cooled wall inlet pipeline, and the shunt water-cooled wall outlet header is connected with a shunt water-cooled wall outlet pipeline; the economizer outlet pipeline comprises a first branch pipeline and a second branch pipeline, the first branch pipeline is connected with the hearth water-cooled wall inlet pipeline, and the second branch pipeline is connected with the shunting water-cooled wall inlet pipeline. The system can greatly improve the hydrodynamic safety of the water cooling wall of the boiler in an ultra-low load interval, meanwhile, the flow resistance of the water cooling wall under full load is not increased, and the operation economical efficiency of the whole unit is not reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-fired power generation, and in particular to a water-cooled wall system of a direct-current boiler. The present invention also relates to a direct-current boiler and a generator set provided with the water-cooled wall system. Background Art

[0002] At present, coal-fired power generation units are mainly configured with supercritical direct-current boilers. The characteristic of direct-current boilers is that the working fluid (water / steam) passes through the furnace water-cooled wall at one time. Therefore, the safety of the water-cooled wall mainly depends on the selection of the mass flow rate of the working fluid in its tube. In principle, the higher the mass flow rate, the stronger the cooling capacity of the working fluid on the water-cooled wall tube, and the safer the hydrodynamic characteristics. However, if the mass flow rate of the water-cooled wall is too high, the flow resistance of the working fluid will be greater, and the energy loss will be greater, thereby reducing the economy of the entire unit. Therefore, in actual engineering, the mass flow rate of the water-cooled wall is usually selected in a more reasonable range.

[0003] Since coal-fired power generation accounts for a high proportion in the traditional power structure, in order to meet the increasing demand for renewable energy, it is necessary to develop coal-fired power unit flexibility and deep peak-shaving technology, which requires the minimum output of power plant boilers to be reduced to an ultra-low load range of 15%-20%, which puts higher requirements on the safety of boiler equipment, especially water-cooled wall equipment.

[0004] When the boiler is running at ultra-low load, the mass flow rate of the furnace water-cooled wall will also be greatly reduced. The water-cooled wall tubes will be at great risk of safety due to insufficient cooling of the working fluid. In serious cases, accidents such as overheating and tube bursting may occur. If you want to ensure safety by increasing the mass flow rate of the water-cooled wall at low load when designing the boiler, you need to select a smaller inner diameter size of the furnace water-cooled wall tubes, and increase the mass flow rate by reducing the flow cross-sectional area of ​​the tubes. However, in this way, the mass flow rate will also increase accordingly under full load and high load conditions, and the resistance of the water-cooled wall will increase accordingly, which will lead to a decrease in the economic efficiency of the unit, forming a contradiction that is difficult to reconcile. Summary of the invention

[0005] The purpose of the present invention is to provide an adjustable dual-flow water-cooled wall system, which can greatly improve the hydrodynamic safety of the boiler water-cooled wall in the ultra-low load range without increasing the flow resistance of the water-cooled wall at full load and reducing the operating economy of the entire unit.

[0006] Another object of the present invention is to provide a once-through boiler and a generator set equipped with the adjustable double-flow water-cooled wall system.

[0007] To achieve the above object, the present invention provides an adjustable dual-flow water-cooled wall system for a once-through boiler, comprising:

[0008] The furnace water-cooled wall is provided with a furnace water-cooled wall inlet header and a furnace water-cooled wall outlet header;

[0009] An economizer, provided with an economizer inlet header and an economizer outlet header and an economizer outlet pipeline;

[0010] Also includes:

[0011] The split water-cooled wall device is provided with a split water-cooled wall inlet header and a split water-cooled wall outlet header; the split water-cooled wall inlet header is connected to the split water-cooled wall inlet pipe, and the split water-cooled wall outlet header is connected to the split water-cooled wall outlet pipe;

[0012] The economizer outlet pipe includes a first branch pipe and a second branch pipe, the first branch pipe is connected to the furnace water-cooled wall inlet pipe, so that the working medium enters the furnace water-cooled wall inlet header, and enters the furnace water-cooled wall outlet header after being heated in the furnace water-cooled wall;

[0013] The second branch pipe is connected to the split water-cooled wall inlet pipe so that the working medium enters the split water-cooled wall inlet header, and after being heated in the split water-cooled wall device, enters the split water-cooled wall outlet header, and then enters the furnace water-cooled wall outlet header through the split water-cooled wall outlet pipe.

[0014] Optionally, the direct-flow boiler is a tower boiler, and the split-flow water-cooled wall device is arranged in the flue gas flow inlet area of ​​the low-temperature heating surface above the furnace of the tower boiler, which is downstream of the flue gas flow of the high-temperature heating surface and upstream of the economizer.

[0015] Optionally, the direct-flow boiler is a II-type boiler, and the split-flow water-cooled wall device is arranged in the tail flue of the II-type boiler, which is in the flue gas area of ​​the low-temperature heating surface and upstream of the economizer.

[0016] Optionally, the furnace water-cooled wall outlet header is connected to a superheater system of a boiler.

[0017] Optionally, an electric stop valve and a regulating valve are provided on the inlet pipe of the split water-cooled wall to control the flow entering the split water-cooled wall by adjusting the valve opening.

[0018] Optionally, the outlet pipe of the split water-cooled wall is provided with a check valve to prevent the working medium from flowing back into the split water-cooled wall.

[0019] Optionally, the pipe material of the split water-cooled wall is 12Cr1MoVG or T91 or austenitic stainless steel material.

[0020] Optionally, the split water-cooled wall inlet pipe is provided with an inlet pressure measuring point, an inlet temperature measuring point, and a flow measuring device to measure the pressure, temperature, and flow of the inlet working fluid of the split water-cooled wall device;

[0021] The outlet pipe of the split water wall is provided with an outlet pressure measuring point and an outlet temperature measuring point to measure the pressure and temperature of the outlet working fluid of the split water wall device, and calculate the enthalpy value of the outlet working fluid of the outlet split water wall device according to the pressure and temperature.

[0022] Optionally, it also includes:

[0023] An enthalpy monitoring unit is used to monitor the enthalpy of the working medium at the outlet of the split water-cooled wall device;

[0024] The control unit is used to adjust the opening of the regulating valve provided on the inlet pipe of the split water-cooled wall to control the flow rate of the working medium at the inlet of the split water-cooled wall device, thereby controlling the superheat of the working medium at the outlet of the split water-cooled wall device to avoid water inflow into the superheater system. The working medium should always be ensured to be superheated steam; if the superheat is insufficient, the flow rate of the working medium at the inlet of the split water-cooled wall device is reduced by adjusting the regulating valve.

[0025] To achieve the above-mentioned other purpose, the once-through boiler provided by the present invention is a tower boiler or a II-type boiler, and has the adjustable double-flow water-cooled wall system described in any one of the above items.

[0026] To achieve the above another object, the present invention provides a generator set, including a boiler, a steam turbine and a generator, wherein the boiler is a once-through boiler provided with the above adjustable double-flow water-cooled wall system.

[0027] The adjustable dual-flow water-cooled wall system provided by the present invention can adjust the mass flow rate of the furnace water-cooled wall when the boiler is under ultra-low load and high load. When the load is ultra-low, the mass flow rate of the furnace water-cooled wall can be increased to provide sufficient cooling capacity and avoid hydrodynamic safety problems; and when the load is high, the mass flow rate of the furnace water-cooled wall can be appropriately reduced by adjusting the diverter water-cooled wall to avoid the high-load mass flow rate being too high and increasing the resistance of the water-cooled wall. Regardless of whether it is applied to a tower boiler or a Π-type boiler, the working fluid flow rate of the furnace water-cooled wall can be adjusted, and different mass flow rates can be provided when the boiler has different load requirements, thereby achieving a balance between low-load safety and high-load economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic structural diagram of an adjustable dual-flow water-cooled wall system provided in the first embodiment of the present invention;

[0029] Figure 2 A schematic structural diagram of an adjustable dual-flow water-cooled wall system provided for a second embodiment of the present invention;

[0030] Figure 3 for Figure 1 A schematic diagram showing a comparison between the adjustable dual-flow water-cooled wall system and the water-cooled wall system before improvement;

[0031] Figure 4 for Figure 2 Schematic diagram comparing the adjustable dual-flow water-cooled wall system and the water-cooled wall system before improvement.

[0032] In the figure:

[0033] 1. Furnace water-cooled wall; 2. Furnace water-cooled wall inlet header; 3. Furnace water-cooled wall outlet header; 4. Diverter water-cooled wall device; 5. Diverter water-cooled wall inlet header; 6. Diverter water-cooled wall outlet header; 7. Economizer; 8. Economizer outlet header; 9. Economizer inlet header; 10. Economizer outlet pipeline; 11. Diverter water-cooled wall inlet pipeline; 12. Diverter water-cooled wall outlet pipeline; 13. Electric stop valve; 14. Control valve; 15. Check valve; 16. Furnace water-cooled wall inlet pipeline; 17. Inlet pressure measuring point; 18. Inlet temperature measuring point; 19. Flow measuring device; 20. Outlet pressure measuring point; 21. Outlet temperature measuring point. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] In this article, the terms "upper, lower, inside, outside" and the like are established based on the positional relationships shown in the drawings. The corresponding positional relationships may also change depending on the drawings, and therefore cannot be understood as absolute limitations on the scope of protection; moreover, relational terms such as "first" and "second" and the like are merely used to distinguish one component from another with the same name, and do not necessarily require or imply any actual relationship or order between these components.

[0036] Please refer to Figure 1 , Figure 1 A schematic structural diagram of an adjustable dual-flow water-cooled wall system provided in the first embodiment of the present invention.

[0037] As shown in the figure, in a specific embodiment, the adjustable dual-flow water-cooled wall system provided by the present invention is used for a tower boiler, which is mainly composed of a furnace water-cooled wall 1, an economizer 7, a split-flow water-cooled wall device 4 and other parts.

[0038] The furnace water-cooled wall 1 is provided with a furnace water-cooled wall inlet header 2 and a furnace water-cooled wall outlet header 3 , and the economizer 7 is provided with an economizer inlet header 9 and an economizer outlet header 8 and an economizer outlet pipe 10 .

[0039] The split water-cooled wall device 4 is arranged at the flue gas flow inlet area of ​​the low-temperature heating surface above the furnace of the tower boiler. It is downstream of the flue gas flow of the high-temperature heating surface and upstream of the economizer 7. The length of the working fluid path of the split water-cooled wall device 4 can be designed to be less than or equal to the length of the working fluid path of the economizer 7.

[0040] The split water-cooled wall device 4 is provided with a split water-cooled wall inlet header 5 and a split water-cooled wall outlet header 6 . The split water-cooled wall inlet header 5 is connected to the split water-cooled wall inlet pipe 11 , and the split water-cooled wall outlet header 6 is connected to the split water-cooled wall outlet pipe 12 .

[0041] The economizer outlet pipe 8 is divided into a first branch pipe and a second branch pipe. The first branch pipe is connected to the furnace water-cooled wall inlet pipe 16 , and the second branch pipe is connected to the split water-cooled wall inlet pipe 11 .

[0042] An electric stop valve 13 and a regulating valve 14 are arranged on the inlet pipe 11 of the split water-cooled wall. The two regulating valves 14 are respectively located upstream and downstream of the electric stop valve 13 . A check valve 15 is arranged on the outlet pipe 12 of the split water-cooled wall.

[0043] An inlet pressure measuring point 17, an inlet temperature measuring point 18, and a flow measuring device 19 are installed on the inlet pipe of the split water-cooled wall, and an outlet pressure measuring point 20 and an outlet temperature measuring point 21 are installed on the outlet pipe of the split water-cooled wall.

[0044] The working process of the above adjustable dual-flow water-cooled wall system is as follows:

[0045] The boiler feed water enters the economizer inlet header 9 through the pipeline, is heated in the economizer 7, passes through the economizer outlet header 8, and then passes through the economizer outlet pipe 10, and is divided into two routes:

[0046] Most of the working medium (such as water) enters the furnace water-cooled wall inlet header 2 through the furnace water-cooled wall inlet pipe 16, and enters the furnace water-cooled wall outlet header 3 after being heated in the furnace water-cooled wall 1.

[0047] Another part of the working fluid passes through the diverter water-cooled wall inlet pipe 11, passes through the electric stop valve 13 and the regulating valve 14, enters the diverter water-cooled wall inlet header 5, is heated in the diverter water-cooled wall device 4, enters the diverter water-cooled wall outlet header 6, and then passes through the diverter water-cooled wall outlet pipe 12 to enter the furnace water-cooled wall outlet header 3.

[0048] The above two parts of working fluid merge at the furnace water-cooled wall outlet header 3 and enter the boiler superheater system together.

[0049] An electric stop valve 13 and a regulating valve 14 are installed on the inlet pipe 11 of the split water-cooled wall, and the flow entering the split water-cooled wall device 4 can be controlled by adjusting the valve opening. When the boiler is in full load and high load area, the electric stop valve 13 and the regulating valve 14 on the inlet pipe 11 of the split water-cooled wall are fully opened, allowing a part of the water to pass through the split water-cooled wall device 4, reducing the flow of the working medium entering the furnace water-cooled wall 1, thereby reducing the resistance of the furnace water-cooled wall 1. When the boiler is running at ultra-low load, the electric stop valve 13 and the regulating valve 14 on the inlet pipe 11 of the split water-cooled wall are closed, or maintained at a small opening, allowing all or most of the feed water to pass through the furnace water-cooled wall 1, so as to increase the mass flow rate of the furnace water-cooled wall 1 and ensure the hydrodynamic safety of the furnace water-cooled wall 1; a check valve 15 is installed on the outlet pipe 12 of the split water-cooled wall to prevent the working medium from flowing back into the split water-cooled wall device 4.

[0050] The split water-cooled wall device 4 is arranged above the tower boiler furnace, downstream of the flue gas flow direction of the high-temperature heating surface and inlet area of ​​the flue gas flow direction of the low-temperature heating surface. The split water-cooled wall is arranged in this area. On the one hand, due to the flue gas temperature here, it can ensure that the working medium produces steam under high-load conditions to meet the evaporation demand of the boiler; at the same time, under low-load conditions, the flue gas temperature here is relatively low, and the material of the split water-cooled wall pipe can be selected from 12Cr1MoVG or T91 or austenitic stainless steel. Even if there is no working medium in the split water-cooled wall device 4 and dry burning occurs, or there is cooling of a trace amount of working medium, the safety of the equipment can be guaranteed and it will not burn.

[0051] The pressure, temperature and flow rate of the inlet working medium of the split water wall device are measured by the inlet pressure measuring point 17, the inlet temperature measuring point 18 and the flow measuring device 19 of the split water wall device. The pressure and temperature of the outlet working medium of the split water wall device are measured by the outlet pressure measuring point 20 and the outlet temperature measuring point 21 of the split water wall device, and the enthalpy value of the outlet working medium of the outlet split water wall device can be calculated according to the pressure and temperature.

[0052] The enthalpy monitoring unit is used to monitor the enthalpy value of the outlet working medium of the split water wall device, and then adjust the opening of the regulating valve 14 set on the inlet pipe of the split water wall through the control unit to control the flow rate of the inlet working medium of the split water wall device, thereby controlling the superheat of the outlet working medium of the split water wall device to avoid water inflow into the superheater system, and always ensure that the working medium is superheated steam. If the superheat is insufficient, the flow rate of the inlet working medium of the split water wall device can be reduced by adjusting the regulating valve.

[0053] Please refer to Figure 2 , Figure 2 A schematic structural diagram of an adjustable dual-flow water-cooled wall system provided for the second embodiment of the present invention.

[0054] As shown in the figure, in another specific embodiment, the adjustable dual-flow water-cooled wall system provided by the present invention is used for a II-type boiler, which is mainly composed of a furnace water-cooled wall 1, an economizer 7, a diverter water-cooled wall device 4 and other parts.

[0055] The furnace water-cooled wall 1 is provided with a furnace water-cooled wall inlet header 2 and a furnace water-cooled wall outlet header 3 , and the economizer 7 is provided with an economizer inlet header 9 and an economizer outlet header 8 and an economizer outlet pipe 10 .

[0056] The diverter water-cooled wall device 4 is arranged in the tail flue of the II-type boiler, which is in the flue gas area of ​​the low-temperature heating surface and upstream of the economizer 7. The length of the working fluid path of the diverter water-cooled wall device 4 can be designed to be less than or equal to the length of the working fluid path of the economizer 7.

[0057] The split water-cooled wall device 4 is provided with a split water-cooled wall inlet header 5 and a split water-cooled wall outlet header 6 . The split water-cooled wall inlet header 5 is connected to the split water-cooled wall inlet pipe 11 , and the split water-cooled wall outlet header 6 is connected to the split water-cooled wall outlet pipe 12 .

[0058] The economizer outlet pipe 8 is divided into a first branch pipe and a second branch pipe. The first branch pipe is connected to the furnace water-cooled wall inlet pipe 16 , and the second branch pipe is connected to the split water-cooled wall inlet pipe 11 .

[0059] An electric stop valve 13 and a regulating valve 14 are provided on the split water wall inlet pipe 11 . The two regulating valves 14 are respectively located upstream and downstream of the electric stop valve 13 . A check valve 15 is provided on the split water wall outlet pipe 12 .

[0060] An inlet pressure measuring point 17, an inlet temperature measuring point 18, and a flow measuring device 19 are installed on the inlet pipe of the split water-cooled wall, and an outlet pressure measuring point 20 and an outlet temperature measuring point 21 are installed on the outlet pipe of the split water-cooled wall.

[0061] The working process of the above adjustable dual-flow water-cooled wall system is as follows:

[0062] The boiler feed water enters the economizer inlet header 9 through the pipeline, is heated in the economizer 7, passes through the economizer outlet header 8, and then passes through the economizer outlet pipe 10, and is divided into two routes:

[0063] Most of the working medium (such as water) enters the furnace water-cooled wall inlet header 2 through the furnace water-cooled wall inlet pipe 16, and enters the furnace water-cooled wall outlet header 3 after being heated in the furnace water-cooled wall 1.

[0064] Another part of the working fluid passes through the diverter water-cooled wall inlet pipe 11, passes through the electric stop valve 13 and the regulating valve 14, enters the diverter water-cooled wall inlet header 5, is heated in the diverter water-cooled wall device 4, enters the diverter water-cooled wall outlet header 6, and then passes through the diverter water-cooled wall outlet pipe 12 to enter the furnace water-cooled wall outlet header 3.

[0065] The above two parts of working fluid merge at the furnace water-cooled wall outlet header 3 and enter the boiler superheater system together.

[0066] An electric stop valve 13 and a regulating valve 14 are installed on the inlet pipe 11 of the split water-cooled wall, and the flow entering the split water-cooled wall device 4 can be controlled by adjusting the valve opening. When the boiler is in full load and high load area, the electric stop valve 13 and the regulating valve 14 on the inlet pipe 11 of the split water-cooled wall are fully opened, allowing a part of the water to pass through the split water-cooled wall device 4, reducing the flow of the working medium entering the furnace water-cooled wall 1, thereby reducing the resistance of the furnace water-cooled wall 1. When the boiler is running at ultra-low load, the electric stop valve 13 and the regulating valve 14 on the inlet pipe 11 of the split water-cooled wall are closed, or maintained at a small opening, allowing all or most of the feed water to pass through the furnace water-cooled wall 1, so as to increase the mass flow rate of the furnace water-cooled wall 1 and ensure the hydrodynamic safety of the furnace water-cooled wall 1; a check valve 15 is installed on the outlet pipe 12 of the split water-cooled wall to prevent the working medium from flowing back into the split water-cooled wall device 4.

[0067] The split water-cooled wall device 4 is arranged in the tail flue of the Π-type boiler, which is in the flue gas area of ​​the low-temperature heating surface. The split water-cooled wall is arranged in this area. On the one hand, due to the flue gas temperature here, it can ensure that the working medium produces steam under high-load conditions to meet the evaporation demand of the boiler; at the same time, under low-load conditions, the flue gas temperature here is relatively low, and the material of the split water-cooled wall pipe can be selected from 12Cr1MoVG or T91 or austenitic stainless steel. Even if there is no working medium in the split water-cooled wall device 4 and dry burning occurs, or there is cooling of a trace amount of working medium, the safety of the equipment can be guaranteed and it will not burn.

[0068] The pressure, temperature and flow rate of the inlet working medium of the split water wall device are measured by the inlet pressure measuring point 17, the inlet temperature measuring point 18 and the flow measuring device 19 of the split water wall device. The pressure and temperature of the outlet working medium of the split water wall device are measured by the outlet pressure measuring point 20 and the outlet temperature measuring point 21 of the split water wall device, and the enthalpy value of the outlet working medium of the outlet split water wall device can be calculated according to the pressure and temperature.

[0069] The enthalpy monitoring unit is used to monitor the enthalpy value of the outlet working medium of the split water wall device, and then adjust the opening of the regulating valve 14 set on the inlet pipe of the split water wall through the control unit to control the flow rate of the inlet working medium of the split water wall device, thereby controlling the superheat of the outlet working medium of the split water wall device to avoid water inflow into the superheater system, and always ensure that the working medium is superheated steam. If the superheat is insufficient, the flow rate of the inlet working medium of the split water wall device can be reduced by adjusting the regulating valve.

[0070] The above embodiments are only preferred solutions of the present invention, and are not limited thereto. On this basis, targeted adjustments can be made according to actual needs to obtain different implementation methods. For example, it can be applied to other types of boilers, etc. Since there are many possible implementation methods, they will not be described one by one here.

[0071] Figure 3 and Figure 4 The comparison between the first embodiment and the second embodiment and the technical solution before the improvement is shown respectively. It can be seen from the figure that the technical solution 1 (tower boiler) and the technical solution 2 (Π-type boiler) before the improvement: all the working fluids enter the furnace water-cooled wall 1 from the economizer 7. The working fluid flow rate of the furnace water-cooled wall of this design cannot be adjusted. If the mass flow rate is to be increased to meet the safe operation of ultra-low load conditions, the mass flow rate will inevitably be too high at full load and high load, which will increase the water-cooled wall resistance and reduce the economy. Therefore, it is difficult to take both high and low loads into account.

[0072] Compared with the previous scheme, the water-cooled wall system of the present invention adopts a dual-flow design and adds a shunt water-cooled wall device 4. Then, when designing the boiler, the furnace water-cooled wall can select a smaller pipe diameter. When the load is high, a part of the working fluid flow is bypassed to the shunt water-cooled wall device 4, thereby reducing the flow in the furnace water-cooled wall, so that the mass flow rate of the furnace water-cooled wall is within a reasonable range, and the water-cooled wall resistance will not be too large due to the high mass flow rate, which will affect the unit economy. When the load is low, the electric stop valve 13 and the regulating valve 14 on the shunt water-cooled wall inlet pipe 11 can be closed, or a small flow rate can be maintained to allow all the working fluid to pass through the furnace water-cooled wall device 4, and maintain a sufficient mass flow rate of the furnace water-cooled wall to ensure hydrodynamic safety.

[0073] It can be seen that the present invention can adjust the mass flow rate of the furnace water-cooled wall 1 at ultra-low load and high load of the direct current boiler. At ultra-low load, the mass flow rate of the furnace water-cooled wall 1 can be increased to provide sufficient cooling capacity and avoid hydrodynamic safety problems; while at high load, the mass flow rate of the furnace water-cooled wall 1 can be appropriately reduced by adjusting the diverter water-cooled wall device 4 to avoid the high load mass flow rate being too high and increasing the resistance of the water-cooled wall.

[0074] In addition to the above-mentioned adjustable double-flow water-cooled wall system, the present invention also provides a direct-flow boiler, which can be a tower boiler or a Π-type boiler, and has the adjustable double-flow water-cooled wall system described above. Regarding the remaining structure of the tower boiler or the Π-type boiler, please refer to the prior art and will not be repeated in this article.

[0075] In addition to the above-mentioned adjustable double-flow water-cooled wall system, the present invention also provides a generator set, which is provided with a boiler, a steam turbine and a generator, wherein the boiler is a direct-flow boiler provided with the above-mentioned adjustable double-flow water-cooled wall system.

[0076] The above is a detailed introduction to the adjustable dual-flow water-cooled wall system, direct-current boiler and generator set provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. Adjustable dual-flow water-cooled wall system for once-through boilers, including: A furnace water-cooled wall (1) is provided with a furnace water-cooled wall inlet header (2) and a furnace water-cooled wall outlet header (3); An economizer (7) having an economizer inlet header (9), an economizer outlet header (8) and an economizer outlet pipe (10); It is characterized by further comprising: The split water-cooled wall device (4) is provided with a split water-cooled wall inlet header (5) and a split water-cooled wall outlet header (6); the split water-cooled wall inlet header (5) is connected to the split water-cooled wall inlet pipe (11), and the split water-cooled wall outlet header (6) is connected to the split water-cooled wall outlet pipe (12); The economizer outlet pipe (10) comprises a first branch pipe and a second branch pipe, the first branch pipe being connected to the furnace water-cooled wall inlet pipe (16) so that the working medium enters the furnace water-cooled wall inlet header (2) and enters the furnace water-cooled wall outlet header (3) after being heated in the furnace water-cooled wall (1); The second branch pipe is connected to the split water-cooled wall inlet pipe (11) so that the working medium enters the split water-cooled wall inlet header (5), is heated in the split water-cooled wall device (4), enters the split water-cooled wall outlet header (6), and then passes through the split water-cooled wall outlet pipe (12) to enter the furnace water-cooled wall outlet header (3).

2. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The once-through boiler is a tower boiler, and the split-flow water-cooled wall device (4) is arranged at the flue gas flow inlet area of ​​the low-temperature heating surface above the furnace of the tower boiler, and is downstream of the flue gas flow of the high-temperature heating surface and upstream of the economizer (7).

3. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The once-through boiler is a II-type boiler, and the split-flow water-cooled wall device (4) is arranged in the tail flue of the II-type boiler, in the flue gas area of ​​the low-temperature heating surface, and upstream of the economizer (7).

4. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The furnace water-cooled wall outlet header (3) is connected to the superheater system of the boiler.

5. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The split water-cooled wall inlet pipe (11) is provided with an electric stop valve (13) and a regulating valve (14) so ​​as to control the flow entering the split water-cooled wall device (4) by adjusting the valve opening.

6. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The split water-cooled wall outlet pipe 12 is provided with a check valve (15) to prevent the working fluid from flowing back into the split water-cooled wall device (4).

7. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The pipe material of the split water-cooled wall device is 12Cr1MoVG or T91 or austenitic stainless steel material.

8. The adjustable dual-flow water-cooled wall system according to claim 1, characterized in that: The split water-cooled wall inlet pipe (11) is provided with an inlet pressure measuring point (17), an inlet temperature measuring point (18), and a flow measuring device (19) for measuring the pressure, temperature, and flow of the working fluid at the inlet of the split water-cooled wall device.

9. The outlet pipe (12) of the split water-cooled wall is provided with an outlet pressure measuring point (20) and an outlet temperature measuring point (21) to measure the pressure and temperature of the outlet working fluid of the split water-cooled wall device, and calculate the enthalpy value of the outlet working fluid of the split water-cooled wall device according to the pressure and temperature.

10. The adjustable dual-flow water-cooled wall system according to claim 8, characterized in that: Also includes: An enthalpy monitoring unit is used to monitor the enthalpy of the working medium at the outlet of the split water-cooled wall device; The control unit is used to adjust the opening of the control valve (14) provided on the inlet pipe of the split water wall to control the flow rate of the working medium at the inlet of the split water wall device, thereby controlling the superheat of the working medium at the outlet of the split water wall device to avoid water inflow into the superheater system, and to ensure that the working medium is always superheated steam; if the superheat is insufficient, the flow rate of the working medium at the inlet of the split water wall device is reduced by adjusting the control valve (14).

11. A once-through boiler is a tower boiler or a II-type boiler, characterized in that: An adjustable double-flow water-cooled wall system according to any one of claims 1 to 9.

12. A generator set, comprising a boiler, a steam turbine and a generator, characterized in that: The boiler is the direct-flow boiler according to claim 10.

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