WO2023168679A1 - Series auxiliary regulation-based steam turbine unit, thermodynamic system and operation method - Google Patents

Abstract

A series auxiliary regulation-based steam turbine unit, a thermodynamic system and an operation method: multiple regulating pressure level groups (6) capable of using full-arc admission are connected in series in front of a conventional pressure level group (41), each regulating pressure level group (6) being provided with a corresponding regulating steam admission channel (10) to convey steam; different regulating pressure level groups (6) are commissioned according to different load intervals, and when the regulating pressure level groups (6) located upstream are commissioned, the regulating pressure level groups (6) located downstream are also commissioned to operate therewith due to the serial connection, so as to achieve the structural adaptability reconstruction of the steam turbine unit, increase the low-load efficiency of the unit, reduce the vibration amplitude, and construct different pressure-level structures merely by means of using length space of the unit along an axial direction. Under medium and low loads, the boiler flue temperature is low and there is a risk of denitration requirements not being met. Thus, a gas extraction pipeline is led out from a tail end of the regulating pressure level groups and connected to an adjustable heater, the water temperature at an admission end of a boiler is increased, and the flue temperature at a denitration site is adjusted according to actual needs, so that the denitration requirements are met.

Description

A steam turbine unit, thermal system and operation method based on series auxiliary regulation Technical field

The invention belongs to the field of thermal conversion technology, and in particular relates to a steam turbine unit, a thermal system and an operating method based on series auxiliary regulation.

Background technique

Steam turbines are widely used in thermal power generation, nuclear power, biomass power generation and other civil power and civilian large-scale carrier ships, as well as aircraft carriers, large ships, nuclear submarines and other military carrier fields. They are one of the most important large-scale power equipment. The low-load operation of the steam turbine not only causes the energy consumption of the unit to rise significantly, but also may cause serious vibration of the unit due to uneven circumferential steam intake under the conventional sequence valve steam distribution method, affecting the safe operation of the unit and affecting the radar protection performance of military ships.

The "dual carbon" strategy promotes the construction of a new power system with new energy as the main body. With the large-scale random fluctuations of photovoltaic, wind power and other new energy power being connected to the grid, basic power, with thermal power as the main body, is forced to fully participate in deep peak shaving. The design of thermal power units mainly considers the operating efficiency under rated load conditions. In the process of deep peak shaving, the power generation efficiency of the unit deteriorates sharply under medium and low load conditions. Compared with rated load conditions, conventional thermal power units operate at 30% of rated load. In this case, coal consumption increases by 30-40g/kW·h, which greatly reduces the comprehensive energy saving and emission reduction benefits of the whole society resulting from making way for new energy.

Based on the technical and structural characteristics of existing steam turbines and thermal systems, under low load conditions, whether the main steam pressure adopts sliding pressure operation, constant pressure operation, or "fixed-slip-fixed" operation, under medium and low loads, The pressure at all levels after the regulation level drops significantly. Under medium and low load conditions, the existing technology cannot effectively utilize the large ideal enthalpy drop between the rated main steam pressure that the boiler can provide and the post-regulation pressure, which directly leads to the failure of the thermal system under medium and low load conditions. The lower cycle efficiency drops significantly and the system energy consumption increases significantly.

Systematically solving the problem of reduced operating efficiency under low-load conditions during deep peak shaving of steam turbine units is a key issue related to energy saving and consumption reduction for civil enterprises, overall energy saving and emission reduction, and even the completion of the national "double carbon" goal on schedule with high quality. It is also a key issue related to The fundamental issue is the single voyage of the carrier equipment and its comprehensive service capability. The vibration problem under low load conditions is a core issue related to the safe operation of equipment and safe military navigation. Therefore, there is an urgent need for a steam turbine unit and thermal system that can maintain high cycle efficiency and controllable vibration performance under medium and low load conditions to solve the current problems.

Contents of the invention

In order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a full-load high-efficiency steam turbine unit, a thermal system and an operating method, which are mainly used to solve the problem of medium and low-level coal-fired thermal power units in the existing technology when participating in the deep peak-shaving process. Problems include low operating efficiency under load, poor adjustment ability, and large vibration.

In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

In a first aspect, the present invention provides a steam turbine unit based on series auxiliary regulation, including a power cylinder, which is any one of a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder. The power cylinder is provided with A conventional steam inlet channel and a conventional pressure stage group. The power cylinder is also provided with at least one regulating pressure stage group. The regulating pressure stage group is coaxially connected in series before the conventional pressure stage group. Each of the regulating pressure stage groups There is at least one pressure stage in the pressure stage group. The pressure stage is composed of a stationary blade cascade located at the front end and a moving blade cascade located at the rear end. Each of the adjustment pressure level groups corresponds to an independent adjustment steam inlet channel. The front end of the regulating steam inlet channel is connected with at least one regulating valve for controlling the steam flow on and off.

Furthermore, the conventional pressure stage group or at least one of the regulated pressure stage groups adopts a full circumferential steam intake method, and no regulating stage is provided at the front end thereof.

Further, the stator blade grid in the frontmost pressure stage in the regulating pressure stage group that is farthest from the conventional pressure stage group is embedded in the inner cylinder of the power cylinder.

Further, the adjustment pressure stage group farthest from the conventional pressure stage group is provided with an adjustment stage, and at least two nozzle groups are provided in the adjustment stage.

Further, the outlet of each adjustment pressure stage group is provided with a corresponding check door assembly, and the check door assembly is used when the corresponding adjustment pressure stage group and its previous adjustment pressure stage group are put into operation. It is turned on and closed when the corresponding regulating pressure stage group is not in operation and the following regulating pressure stage group or conventional pressure stage group is in operation.

Further, the outlet of each adjustment pressure stage group is provided with an annular channel, and the check door assembly is provided at the annular channel.

Further, the check door assembly includes a plurality of check door units arranged sequentially along the circumferential direction. The check door unit includes a rotation shaft and an opening and closing member, and the opening and closing member can rotate along the rotation shaft. , the axial projection of the opening and closing member in the closed state is an irregular surface composed of an inner edge line, a first edge line, a second edge line and an outer edge line. The irregular surfaces do not overlap each other. In the closed state Below, the inner edge lines of multiple opening and closing components are connected end to end to form a circle that coincides with the inner circle of the annular channel, and the outer edge lines of multiple opening and closing components are connected end to end to form a closed figure.

Further, the outer edge line is a straight line, the closed figure is a polygon, the number of sides of the polygon is ≥ 3, and the central axis of the rotation axis coincides with the side lines of the polygon along the axial projection.

Further, the coverage area of the inscribed circle of the polygon is greater than or equal to the outer circle of the annular channel.

Further, the outer edge line is an arc, the closed figure is a circle, and the coverage area of the circle is greater than or equal to the outer circle of the annular channel.

Further, the opening and closing member is flipped outward or inward along the rotation axis according to the front and rear pressure difference of the area where it is located.

Further, the rotation angle of the opening and closing member from the closed state to the open state is no more than 135°.

Further, the check door unit further includes two positioning members, and the two positioning members are respectively used to fix or buffer the opening and closing members in the closed state and the open state.

In a second aspect, the present invention also provides a thermal system based on series auxiliary regulation, including a boiler and a steam turbine unit based on series auxiliary regulation as described above. The power cylinder is a high-pressure cylinder, and the boiler passes through a piping system. Connected one by one to the regulating steam inlet channels, the pipeline system is provided with a main steam valve for controlling the on-off flow of the main steam flow of the boiler, between the main steam valve and each of the regulating steam inlet channels Provide at least one regulating valve.

Further, the pipeline system includes a main steam pipeline and at least one branch steam pipeline network, the main steam valve is located on the main steam pipeline, and the branch steam pipeline network is composed of several branch steam pipes. Each bronchial tube is provided with a regulating valve.

Further, it also includes a heat recovery system, the heat recovery system includes at least one adjustable heater, and at least one steam outlet of the adjustment pressure stage group is connected to the adjustable heater through an exhaust pipe. The gas pipeline is provided with a gas regulating valve assembly, and the adjustable heater is connected to the boiler.

In a third aspect, the present invention also provides an operating method of a thermal system based on series auxiliary regulation, which includes the following steps:

According to the distance between each adjustment pressure level group and the first pressure level of the conventional pressure level group, from near to far, they are defined as the first adjustment pressure level group, the second adjustment pressure level group...the nth adjustment pressure level group, and the The adjustment steam inlet channels corresponding to the adjustment pressure stage group are defined in sequence as the first adjustment steam inlet channel, the second adjustment steam inlet channel... the nth adjustment steam inlet channel, and the conventional steam inlet channel is determined as the zeroth steam inlet channel;

Divide the operating load of the thermal system into n+1 load intervals, and each load interval corresponds to one of the regulated steam inlet channels;

According to the current operating load rate of the thermal system or according to the set target load rate, determine the target load interval that the thermal system needs to enter, and switch to the regulated steam inlet channel corresponding to the target load interval.

Further, when the load of the thermal system is increased, the final adjustment steam inlet channel to be switched to is determined according to the load increase rate or the target load rate requirement;

Directly open the final adjustment steam inlet channel, or;

If there are other intermediate adjustment steam inlet channels between the final adjustment steam inlet channel and the current adjustment steam inlet channel, the intermediate adjustment steam inlet channels will be opened sequentially or simultaneously starting from the current adjustment steam inlet channel until the final adjustment steam inlet channel is opened. ;

Determine whether the current load reaches the set value. If it does, gradually close other adjustment steam inlet channels except the final adjustment steam inlet channel.

Further, when the load of the thermal system is reduced, the final adjustment steam inlet channel to be switched to is determined according to the load reduction rate requirement;

Gradually close the regulating valve corresponding to the current regulating steam inlet channel;

Determine whether the current load reaches the set value. If it does, gradually open the adjustment valve corresponding to the final adjustment steam inlet channel, and gradually close the adjustment valve corresponding to the current adjustment steam inlet channel.

Further, when the load rate of the thermal system is lower than X% of the rated load, the gas regulating valve assembly is opened and the steam in the corresponding regulating pressure stage group is input into the adjustable heater.

Further, the temperature of the boiler flue is detected. If the temperature of the boiler flue is lower than the set temperature value, the gas regulating valve assembly is opened, and the boiler flue is adjusted by controlling the opening of the gas regulating valve assembly. temperature to be higher than the set temperature value.

Compared with the prior art, the present invention at least includes the following beneficial effects:

There are multiple regulating pressure stage groups connected in series before the conventional pressure stage group. Each regulating pressure stage group has a corresponding regulating steam inlet channel to transport steam. According to different load intervals, different regulating pressure stage groups are put into operation, and when When the upstream regulating pressure stage group is put into operation, the downstream regulating pressure stage group will also be put into operation due to the series connection, realizing the adaptive reconstruction of the structure of the steam turbine unit, improving the low load efficiency of the unit, and only using the unit on the shaft. The upward length space can realize the construction of structures with different pressure levels;

Since the pressure stage group can fully adopt the full circumferential steam intake method, it can eliminate the problem of uneven circumferential steam intake caused by partial steam intake under low load conditions, thus causing excessive vibration of the unit;

The main steam valve and regulating valve set in the pipeline system are used to control the on and off of each regulating steam inlet channel. A multi-stage branch steam pipe network can also be set up to achieve a smooth transition when switching between different regulating steam inlet channels. Avoid sudden changes in steam flow and eliminate potential vibration and safety hazards under low load conditions;

Under medium and low loads, the temperature of the boiler flue is low, and there is a risk of not meeting the denitration requirements. By leading an exhaust pipe at the end of the adjustment pressure stage group and connecting it to the adjustable heater, the water temperature at the inlet of the boiler can be increased and adjusted according to actual needs. The smoke temperature at the denitrification point is required to meet the denitrification requirements.

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of the drawings

The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, without exerting creative efforts, other embodiments can be obtained based on the following drawings. Picture attached.

Figure 1 is a half-section schematic diagram of a steam turbine unit based on series auxiliary regulation provided by the present invention.

Figure 2 is a schematic structural diagram of the check door assembly in a closed state according to an embodiment of the present invention.

Figure 3 is a schematic structural diagram of the backstop door assembly in an open state according to an embodiment of the present invention.

Figure 4 is a schematic structural diagram of the check door assembly in a closed state in another embodiment of the present invention.

Figure 5 is a schematic structural diagram of the backstop door assembly in an open state according to another embodiment of the present invention.

Figure 6 is a schematic structural diagram of a thermal system based on series auxiliary regulation provided by the present invention.

Figure 7 is a schematic diagram of a piping system in one embodiment.

Figure 8 is a schematic diagram of a piping system in another embodiment.

Detailed ways

The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation or a specific orientation. construction and operation, and therefore should not be construed as limitations of the invention. Furthermore, the terms “first”, “second” and “third” are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, when a specific device is described as being located between a first device and a second device, there may or may not be an intervening device between the specific device and the first device or the second device. When a specific device is described as being connected to another device, the specific device may be directly connected to the other device without an intervening device, or may not be directly connected to the other device but with an intervening device.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered a part of the specification.

In the first aspect, referring to Figure 1 , this embodiment discloses a steam turbine unit based on series auxiliary regulation, including a power cylinder 2, which is any one of a high-pressure cylinder 4, a medium-pressure cylinder and a low-pressure cylinder. , the power cylinder 2 is provided with a conventional steam inlet channel 42 and a conventional pressure stage group 41. However, since the operating load of the unit will change from time to time, the conventional pressure stage group 41 is designed according to the rated load condition and cannot adapt to medium and low pressure levels. Load conditions, in view of this, this embodiment is also provided with at least one regulating pressure stage group 6 in the power cylinder 2. The regulating pressure stage group 6 is sequentially coaxially connected in series with the conventional pressure stage group 41. Each regulating pressure stage group 6 is provided with at least one pressure stage 7. The pressure stage 7 is composed of a stationary blade cascade 8 located at the front end and a moving blade cascade 9 located at the rear end. The stationary blade cascade 8 is composed of a plurality of stationary blades arranged in the circumferential direction. The moving blade cascade 9 consists of a plurality of moving blades arranged in the circumferential direction. Two stationary blades 8 and moving blades 9 in tandem form a pressure level 7. The pressure level 7 responds to the main steam generated from the boiler 1. To do work, each regulating pressure stage group 6 corresponds to an independent regulating steam inlet channel 10. The front end of the regulating steam inlet channel 10 is connected with at least one regulating valve 11 for controlling the steam flow on and off. Along the axial direction, two regulating pressure The pressure stages 7 of the stage group 6 are separated by the regulating steam inlet passage 10 , and the pressure stages of the last regulating pressure stage group and the conventional pressure stage group 41 are separated by the conventional steam inlet passage 42 .

It should be noted that the power cylinder 2 in the steam turbine unit can be a high-pressure cylinder 4, an intermediate-pressure cylinder and a low-pressure cylinder, and at least one regulating pressure stage group connected in series can be provided in the high-pressure cylinder 4, the intermediate pressure cylinder and the low-pressure cylinder. 6. Therefore, it should be considered that no matter which one or more power cylinders 2 are provided with the adjusting pressure stage group 6, it is within the scope of protection claimed by this embodiment, and will not be described one by one here.

Each regulating steam inlet channel 10 has a corresponding regulating valve 11 that controls its steam flow on and off. It should be noted that one regulating valve 11 can control one regulating steam inlet channel 10, or one regulating valve 11 can control both. There are one or more regulating steam inlet channels 10, or one regulating steam inlet channel 10 can be controlled by multiple regulating valves 11, or it can be a comprehensive application of the above various methods.

When the unit is operating normally under high load, the conventional steam inlet channel 42 is opened and delivers main steam, and the conventional pressure stage group 41 is put into operation; when the unit is operating under medium and low load, it can be switched to different adjustments according to the specific load range. Pressure stage group 6, each regulating pressure stage group 6 is connected in series along the coaxial direction of the conventional pressure stage group 41. Each regulating pressure stage group 6 is provided with a pressure stage 7 for doing work, that is, each pressure stage 7 is arranged along the coaxial direction of the conventional pressure stage group 41. are connected in series in the coaxial direction, and each pressure stage 7 is in a standby state. Therefore, when the upstream regulating pressure stage group 6 is put into operation, the pressure stages 7 in the downstream regulating pressure stage group 6 will also be put into operation. By enabling different By adjusting the steam inlet channel 10, the lower the load of the unit, the more pressure stages 7 can be put into operation, and the downstream pressure stage 7 can be shared. Different pressures can be achieved by simply using the length space of the stage group in the axial direction. The construction of the level 7 structure realizes the adaptive reconstruction of the structure of the steam turbine unit and improves the low-load efficiency of the unit.

It can be seen that each adjustment pressure stage group 6 is a backup pressure stage group of the regular pressure stage group 41, which can realize dynamic reconstruction of the pressure stage group actually put into operation in the power cylinder 2 according to the actual load situation. When the load is lower, , the more pressure stages 7 are invested, and in this embodiment, each pressure stage 7 is arranged along the axial direction, and the downstream pressure stage 7 can be utilized only by opening the upstream regulating steam inlet channel 10, and the utilization rate of pressure stage 7 is high. The unit has strong adaptability and high efficiency.

In some embodiments, the conventional pressure stage group 41 or at least one regulated pressure stage group 6 adopts a full circumferential steam inlet method, and no regulating stage is provided at its front end. Furthermore, no regulating stage using partial steam inlet is provided. Through the above The steam intake method, coupled with switching to the regulated steam intake channel 10 that allows more pressure stages 7 to be put into operation at low load, can eliminate the vibration deviation of the unit caused by uneven circumferential steam intake caused by partial steam intake under low load conditions. A big problem, it reduces the vibration amplitude of the unit under low load conditions.

In some embodiments, each regulating pressure stage group is arranged in series from near to far along the axial direction. Under the lowest load condition, the regulating pressure stage group 63 farthest from the conventional pressure stage group 41 is turned on. In order to improve the performance of the lowest load In order to improve the operating stability of the steam turbine unit, embed the stator blade cascade in the frontmost pressure stage in the farthest regulating pressure stage group 63 into the inner cylinder 26 of the power cylinder 2. Since the inner cylinder 26 is a stator, it is stationary. It is dynamic and has high stability, so it can strengthen the connection strength of the static blade cascade of the frontmost pressure stage 63.

In some embodiments, the adjustment pressure stage group 6 farthest from the conventional pressure stage group 41 is provided with an adjustment stage, and at least two nozzle groups are provided in the adjustment stage, that is, under the lowest load condition, an adjustment stage needs to be added. The function of the regulating stage is utilized to improve the operating efficiency when all pressure stages 7 in the regulating pressure stage group 6 are put into operation.

In this embodiment, the outlet of each adjustment pressure stage group 6 is provided with a corresponding check door assembly 12, and each adjustment pressure stage group 6 has a corresponding check door assembly 12. The adjustment pressure stage group 6 is in front, and the check door assembly 12 is in the back. The check door assembly 12 is used to open when the corresponding regulating pressure stage group 6 and the regulating pressure stage group 6 before it are put into operation. When the corresponding regulating pressure stage group 6 is not is put into operation, and the subsequent regulated pressure stage group 6 or conventional pressure stage group 41 is closed when it is put into operation. The above description of the front and rear directions corresponds to the direction of steam flow, that is, the check door assembly 12 is equivalent to an on-off valve, which It can ensure that among the pressure stages 7 connected in series along the same axis, only the actually required part of the pressure stage 7 has steam passing through it, while the other part of the pressure stage 7 that does not need to be put into operation does not pass steam, and prevents this part of the pressure stage 7 from idling, causing Blowing phenomenon reduces system efficiency.

In more detail, three regulating pressure stage groups 6 are provided before the conventional pressure stage group 41 , which are respectively the first regulating pressure stage group 61 , the second regulating pressure stage group 62 and the third regulating pressure stage group 63 from near to far. , each regulating pressure stage group 6 is provided with two pressure stages 7, a total of six pressure stages 7; immediately after each regulating pressure stage group 6 is its corresponding check door assembly 12, the regulating pressure stage group 6 corresponds one-to-one with the check door assembly 12. For example, when the second adjustment pressure stage group 62 is put into operation, the second check door assembly and the first check door assembly will be opened, and the first adjustment pressure stage group 61, A total of four pressure stages in the second regulating pressure stage group 62 are put into operation, but the third check door assembly is closed, that is, the two pressure stages of the third regulating pressure stage group 63 are not put into operation and do not rotate.

Furthermore, the outlet of each adjustment pressure stage group 6 is provided with an annular channel 104. The adjustment steam inlet channel 10 of the next stage adjustment pressure stage group of the current adjustment pressure stage group performs intake air distribution through this annular channel 104, and conversely. The check door assembly 12 is located at the annular channel 104. By utilizing the space of the annular channel 104, the check door assembly 12 can not only block the regulating steam inlet channel 10 of the next stage outward, but also block the regulating pressure of the current stage inward. The outlet of stage group 6; for example, in the previous example, the position of the third check valve assembly is the annular channel 104 corresponding to the adjustment steam inlet channel 10 of the second adjustment pressure stage group 62. When the third check valve When the assembly is closed, the steam in the regulating steam inlet channel 10 of the second regulating pressure stage group 62 can smoothly pass through the annular channel 104, and then enter the two pressure levels in the second regulating pressure stage group 62 and the first regulating pressure stage in turn. Two pressure stages in Group 61.

Referring to FIGS. 2 to 5 , in this embodiment, the check door assembly 12 includes a plurality of check door units 13 arranged sequentially along the circumferential direction. Each check door unit 13 is connected end to end. The check door unit 13 includes a rotation shaft 15 and the opening and closing member 14. The opening and closing member 14 can rotate along the rotation axis 15, and the position of the rotation axis 15 is fixed. The opening and closing member 14 has two states, namely the open state and the closed state. The opening and closing state in the closed state The axial projection of the member 14 is an irregular surface composed of an inner edge line 21, a first edge line 22, a second edge line 23 and an outer edge line 24. The inner edge line 21 and the outer edge line 24 are located in the inner and outer directions respectively. The first side line 22 and the second side line 23 connect the left and right endpoints of the inner edge line 21 and the outer edge line 24 respectively. In the axial projection, the corresponding irregular surfaces of each opening and closing member 14 do not overlap with each other. In the closed state Below, the circle formed by the inner edge lines 21 of the multiple opening and closing members 14 connected end to end coincides with the inner circle 17 of the annular channel 104, and the outer edge lines 24 of the multiple opening and closing members 14 are connected end to end to form a closed figure. When multiple When the check door unit 13 is closed, the circular shape formed by the multiple inner edge lines 21 can contact the inner circle 17 of the corresponding annular channel 104 to ensure sealing and effectively prevent steam from flowing to the upstream area.

With reference to Figures 2 and 3, as an embodiment, the outer edge line 24 is a straight line, the closed figure is a polygon, the number of sides of the polygon is ≥ 3, the central axis of the rotation axis 15 coincides with the edge line of the polygon along the axial projection, and the opening and closing The member 14 rotates along the rotation axis 15, which is equivalent to the irregular surface rotating along the edges of the polygon.

Preferably, the coverage area of the polygonal inscribed circle is greater than or equal to the outer circle 16 of the annular channel 104, that is, when the check door assembly 12 is in the open state, each opening and closing member 14 can be completely opened after being flipped outward along the rotation axis 15. By exposing the outer circle 16 of the annular channel 104, the flow of steam in the annular channel 104 is no longer affected by the check door assembly 12, ensuring smooth flow.

4 and 5 , as another embodiment, the outer edge line 24 is an arc, the closed figure is a circle, and the outer edge lines 24 of each opening and closing member 14 are connected end to end to form a closed circle. When the two endpoints of the outer edge line 24 are connected by a straight line, the virtual straight line corresponding to each opening and closing member 14 is also connected end to end to form a polygon. Furthermore, the coverage area of the circle is greater than or equal to the outer circle of the annular channel 104 16. In addition, when the opening and closing member 14 is turned outward by 180°, that is, the outer edge line 24 is turned inward, the inner edge line 21 is turned outward, and the coverage area of the figure connected by the outer edge line 24 also completely covers the annular shape. The outer circle 16 of the channel 104 ensures that even in the most extreme state, it does not occupy the flow area of the annular channel 104.

In this embodiment, the opening and closing member 14 flips outward or inward along the rotation axis 15 according to the front and rear pressure difference of the area where it is located. That is, there is no other execution member between the opening and closing member 14 and the rotation axis 15. The opening and closing of 14 completely relies on the action of steam air flow. When the regulating pressure stage group 6 in front of the check door assembly 12 is put into operation, each opening and closing component 14 is opened by the impact of the steam air flow in front; when the pressure stage group 6 in front of the check door assembly 12 is put into operation, When the regulating pressure stage group 6 is not in operation, and the regulating air inlet channel immediately behind it is opened to circulate steam, each opening and closing component 14 is closed by the impact of the steam flow behind it. The entire opening and closing process does not need to be controlled by a specific executive component. According to It changes with the change of steam flow, and the opening and closing process is stable and reliable without control.

Preferably, the rotation angle of the opening and closing member 14 from the closed state to the open state is no more than 135°. Furthermore, the backstop door unit 13 also includes two positioning members, and the two positioning members are respectively used to fix or buffer the opening and closing member 14 in the open state. The opening and closing member 14 in the closed state and the open state.

It should be noted that due to the high speed of the steam flow, the opening and closing member 14 may be suddenly impacted whether it is opened or closed. In order to eliminate the sudden impact or vibration of the opening and closing member 14, in the closed state of the opening and closing member 14 Positioning members are respectively provided at the two position points of the open state and the open state. First, the opening and closing member 14 can be fixed. Second, the buffering effect can be achieved to avoid damage to the cylinder.

Referring to Figure 6, in the second aspect, this embodiment provides a thermal system based on series auxiliary regulation, including a boiler 1 and a steam turbine unit based on series auxiliary regulation in the above embodiment, in which the power cylinder 2 is a high-pressure cylinder 4. Boiler 1 is connected one by one to the regulated steam inlet channel 10 through a piping system. The pipeline system is provided with a main steam valve 5 for controlling the on-off of the main steam flow of boiler 1. The main steam valve 5 is connected to each regulated steam inlet channel. There is at least one regulating valve 11 between 10. The main steam valve 5 is used to control the on-off of the main steam at the outlet of boiler 1, and the regulating valve 11 is used to control the on-off of one or more regulating steam inlet channels 10. Of course, a regulating valve 11 that can control the flow ratio can also be used, and the steam flow rate can be changed by controlling the opening of the regulating valve 11 .

It should be noted that in order to realize the operation switching between the regulating steam inlet channels 10, there are many corresponding relationships between the regulating valve 11 and the regulating steam inlet channels 10. These corresponding relationships are all realized by the pipeline system. In more detail, the pipeline system The road system includes a main steam pipeline and at least one level of branch steam pipe network. The main steam valve 5 is located on the main steam pipeline. The branch steam pipe network is composed of several branch pipes, and each branch pipe is equipped with a regulating valve 11.

Referring to Figure 7, as an implementation method, a one-point-multiple approach is adopted. One main steam pipe is matched with a first-level branch steam pipe network. There are as many branch pipes as there are regulating steam inlet channels 10, and one regulating valve 11 is directly connected. Controls a regulating steam inlet channel 10, and there is only one regulating valve 11 between the regulating steam inlet channel 10 and the main steam valve 5;

Referring to Figure 8, as another implementation mode, a method of dividing one into multiples and then into many is used. One main steam pipeline is matched with a two-level branch steam pipeline network, that is, the main steam pipeline is directly connected to the first-level branch steam pipeline network. The first-level branch steam pipe network is directly connected to the second-level branch steam pipe network. In the embodiment with three regulating steam inlet channels 10, the first-level branch steam pipe network has two branch steam pipes, and the second-level branch steam pipe network has two branch steam pipes. The pipe network has three branch pipes. Each branch pipe in the first-level branch steam pipe network is connected to the two branch pipes in the second-level branch steam pipe network. The advantage of this arrangement is that when it is necessary to adjust the steam inlet across When the channel 10 is switched and adjusted, the adjustment steam inlet channel 10 in the middle can play a transitional role, and there is a transitional stage.

Additionally, if the power cylinder 2 is a medium-pressure cylinder, and at least one regulating pressure stage group 6 is provided in the medium-pressure cylinder, then this regulating pressure stage group 6 is connected to the regenerated pipeline in the boiler 1. Similarly, The connection relationship between the regenerated pipeline and the medium-pressure cylinder regulating pressure stage group 6 can refer to the connection relationship between the main steam pipeline of boiler 1 and the high-pressure cylinder 4 regulating pressure stage group 6, such as power cylinder 2 The same applies to low-pressure cylinders, so I won’t go into details here.

Referring to Figure 6, in some embodiments, a heat recovery system 3 is also included. The heat recovery system 3 includes an adjustable heater 19. The end of the adjustment pressure stage group 6 is connected to the adjustable heater 19 through an exhaust pipe, usually at The annular channel 104 after the pressure stage 7 of the regulated pressure stage group 6 which is closest to the conventional pressure stage group 41 is connected to the air extraction pipeline. The air extraction pipeline is provided with a gas regulating valve assembly 18. The gas regulating valve assembly 18 can adjust the air pumping pipe. On-off and its flow rate, the adjustable heater 19 is connected to the boiler 1. This purpose is that when it is under medium and low load, the temperature of the flue of the boiler 1 is low, and there is a risk of not meeting the denitration demand. By adjusting the pressure An exhaust pipe is led out from the end of stage group 6 and connected to the adjustable heater 19 to increase the water temperature at the inlet end of boiler 1 and adjust the smoke temperature at the denitration place according to actual needs to meet the denitration requirements.

In a third aspect, this embodiment provides a method for operating a thermal system based on series auxiliary regulation, which includes the following steps:

S1: According to the distance between each adjustment pressure level group 6 and the first pressure level 7 of the conventional pressure level group 41, from near to far, it is defined as the first adjustment pressure level group 61, the second adjustment pressure level group 62...the nth adjustment Pressure stage group 6, the regulating steam inlet channel 10 corresponding to the regulating pressure stage group 6 is defined in sequence as the first regulating steam inlet channel 101, the second regulating steam inlet channel 102... the nth regulating steam inlet channel 10, the conventional steam inlet channel 42 is determined as the zeroth steam inlet channel;

S2: Divide the operating load of the thermal system into n+1 load intervals, and correspond each load interval to a regulating steam inlet channel 10;

In this embodiment, n=3, that is, there are three regulated steam inlet channels 10 arranged in sequence from near to far, and immediately before the conventional pressure stage group 41 is the conventional steam inlet channel 42, that is, the zeroth steam inlet channel ;A total of 4 load intervals are divided, namely [100%, 90%], [90%, 70%], [70%, 50%] and [50%, 30%], [100%, 90%] load The interval corresponds to only opening the zeroth steam inlet channel, and only the conventional pressure stage group 41 is put into operation; the [90%, 70%] load interval corresponds to only opening the first regulated steam inlet channel 101, the first regulated pressure stage group 61 and the conventional pressure stage Group 41 is put into operation; the [70%, 50%] load interval corresponds to only opening the second adjustment steam inlet channel 102, and the second adjustment pressure level group 62, the first adjustment pressure level group 61 and the conventional pressure level group 41 are put into operation; [ 50%, 30%] load interval corresponds to only opening the third adjustment steam inlet channel 103, the third adjustment pressure level group 63, the second adjustment pressure level group 62, the first adjustment pressure level group 61 and the conventional pressure level group 41 are all turned on transport.

S3: According to the current operating load rate of the thermal system, or according to the set target load rate, determine the target load interval that the thermal system needs to enter, and switch to the regulated steam inlet channel 10 corresponding to the target load interval. If the load interval does not occur If the load range changes, the current steam inlet channel operation is maintained. If the load interval changes, the current regulated steam inlet channel 10 is switched to the regulated steam inlet channel 10 corresponding to the target load interval.

It can be seen that as the load of the unit changes, the number of pressure levels 7 required to be put into operation will also change. By automatically reconstructing the thermal system state, switching to different regulating steam inlet channels 10, so that after reconstruction The number of pressure levels 7 better matches the current load rate. In order to achieve this goal, there are many ways to combine the load interval and the adjustment steam inlet channel 10. The most basic one is that one load interval corresponds to one adjustment steam inlet channel 10. Of course, One load interval may correspond to two or more regulated steam inlet passages 10 . The reason for switching and adjusting the steam inlet channel 10 can be passive or active, that is, when the unit load changes, the adjustment of the steam inlet channel 10 can be switched accordingly; it can also be to artificially set a target load rate. , while other devices in the thermal system are being adjusted, the steam inlet channel 10 is also actively switching.

In some embodiments, when the load of the thermal system increases, the final adjustment steam inlet channel that needs to be switched is determined according to the load increase rate or the target load rate requirement; it should be noted that, whether it is actively or passively switching to adjust the intake steam Channel 10, as long as the triggering conditions for switching and regulating the steam inlet channel 10 are met, a parameter for the load increase rate or target load rate requirement will be generated, for example, whether it is necessary to switch from the third regulated steam inlet channel 103 to the first regulated steam inlet channel 101 or Switch to the second regulated steam inlet channel 102, which will form a final regulated steam inlet channel;

After determining the final adjustment steam inlet channel, you can directly open the final adjustment steam inlet channel. This method is to increase the load adjustment rate. Directly open the final adjustment steam inlet channel and then use other factors to stabilize it. This method is a static adjustment method. ;

Or this method can be adopted, that is, if there are other intermediate adjustment steam inlet channels 10 between the final adjustment steam inlet channel and the current adjustment steam inlet channel, the intermediate adjustment steam inlet channels 10 will be opened sequentially starting from the current adjustment steam inlet channel or simultaneously. , until the final adjustment steam inlet channel is opened; that is, if it is necessary to switch from the third adjustment steam inlet channel 103 to the first adjustment steam inlet channel 101, and there is a second adjustment steam inlet channel 102 between the two, then switching During the process, the second adjustment steam inlet channel 102 needs to be opened first to play a transitional role, and finally the first adjustment steam inlet channel 101 is opened; it can be seen that this method is a dynamic adjustment method, and each of them is used during the process of increasing the load. Adjusting the opening state of the steam inlet channel 10 will change;

In the process of switching and adjusting the steam inlet channel 10, it is judged whether the current load reaches the set value. If it reaches the set value, and the load is stabilized by adjusting the boiler 1, the adjustment steam inlet channel 10 or the conventional steam inlet channel 42 will no longer be opened downwards. , gradually close other adjustment steam inlet channels 10 except the final adjustment steam inlet channel, that is, first close the third adjustment steam inlet channel 103, and then close the second adjustment steam inlet channel 102. It should be noted that when gradually closing, except for the final adjustment steam inlet channel, When adjusting the steam inlet channel 10 other than the steam inlet channel, they should be closed sequentially from far to near. Of course, they can also be closed at the same time, but they need to be closed slowly during the closing process.

In addition, if it occurs during the dynamic adjustment process, for example, during the process of switching from the third regulated steam inlet channel 103 to the first regulated steam inlet channel 101, when the second regulated steam inlet channel 102 is opened, the load has reached the set value, then Stay in the second regulated steam inlet channel 102 and no longer open the first regulated steam inlet channel 101. It can be seen that in some embodiments, whether the current load reaches the set value is used as the first determination priority for opening the adjusted steam inlet channel 10. .

Additionally, when in the transitional stage, that is, when the second regulated steam inlet passage 102 is opened, a certain proportion of the second regulated steam inlet passage 102 can be opened first, and a certain proportion of the third regulated steam inlet passage 103 can be closed. The steam channel 102 is opened to a set proportion or when the third regulated steam inlet channel 103 is closed to a certain proportion, and then the first regulated steam inlet channel 101 is opened, the sum of the openings of the three regulated steam inlet channels 10 can be calculated according to a certain functional relationship or By controlling with a certain value, the first regulated steam inlet passage 101 is finally opened, and the third regulated steam inlet passage 103 and the second regulated steam inlet passage 102 are closed in turn.

In some embodiments, when the load of the thermal system is reduced, the final adjustment steam inlet channel to be switched is determined according to the load reduction rate requirement; it should be noted that whether the adjustment steam channel 10 is switched actively or passively, as long as When the trigger condition for switching the regulated steam inlet channel 10 is met, a parameter for the load reduction rate requirement will be generated, for example, whether it is necessary to switch from the first regulated steam inlet channel 101 to the third regulated steam inlet channel 103 or to the second regulated steam inlet channel. 102, that is, a final adjustment steam inlet channel will be formed;

Gradually close the regulating valve 11 corresponding to the current regulating steam inlet channel;

Determine whether the current load reaches the set value. If it does, and when the load is stabilized by adjusting the boiler 1, gradually open the regulating valve 11 corresponding to the final adjustment of the steam inlet channel, and close the adjustment valve 11 corresponding to the current adjustment of the steam inlet channel.

In more detail, if you need to switch from the first regulated steam inlet channel 101 to the third regulated steam inlet channel 103, first, gradually close the regulating valve 11 of the first regulated steam inlet channel 101 according to the load reduction rate required by the dispatch. When the load reaches the set value, while stabilizing the load by adjusting the boiler 1, the regulating valve 11 of the third regulating steam inlet channel 103 is gradually opened, and the regulating valve 11 of the first regulating steam inlet channel 101 is slowly closed.

In some embodiments, when the load rate of the thermal system is lower than X% of the rated load, the gas regulating valve assembly 18 is opened, and the steam in the corresponding regulating pressure stage group 6 is input into the adjustable heater 19, where, 20 %<x%<60%. Preferably, according to system optimization, conventional subcritical units can determine x% to be about 40% through calculation verification. That is, when the unit load rate is lower than the set value, the steam in the regulated pressure stage group 6 needs to flow back to the adjustable heater 19 and then flow back to the boiler 1.

In some embodiments, the flue temperature of the boiler 1 is detected. If the flue temperature of the boiler 1 is lower than the set temperature value, the gas regulating valve assembly 18 is opened. By controlling the opening of the gas regulating valve assembly 18, the pressure level is adjusted. The amount of steam extracted from group 6 is returned to adjust the flue temperature of boiler 1 to a value higher than the set temperature.

In summary, compared with the existing technology, the above embodiments provide a steam turbine unit, a thermal system and an operating method based on series auxiliary regulation. There are multiple regulating pressure stage groups 6 connected in series before the conventional pressure stage group 41. Each regulating pressure Each stage group 6 has a corresponding regulating steam inlet channel 10 to transport steam. According to different load intervals, different regulating pressure stage groups 6 are put into operation, and when the regulating pressure stage group 6 located upstream is put into operation, the downstream regulating pressure Stage 6 will also be put into operation due to the series connection, realizing the adaptive reconstruction of the structure of the steam turbine unit, improving the low-load efficiency of the unit, and only using the length of the unit in the axial direction, different pressure stage 7 structures can be realized construction;

Since the adjustment pressure stage group 6 can fully adopt the full circumferential steam intake method, it can eliminate the problem of uneven circumferential steam intake caused by partial steam intake under low load conditions, thereby causing excessive vibration of the unit;

The main steam valve 5 and the regulating valve 11 set in the pipeline system are used to control the on and off of each regulating steam inlet channel 10. A multi-stage branch steam pipe network can also be set up to achieve switching between different regulating steam inlet channels 10. Smooth transition to avoid sudden changes in steam flow and eliminate potential vibration and safety hazards under low load conditions;

Under medium and low loads, the temperature of the flue of boiler 1 is low, and there is a risk of not meeting the denitrification demand. By leading an exhaust pipe at the end of the adjustment pressure stage group 6 and connecting it to the adjustable heater 19, the water temperature at the inlet end of boiler 1 is increased. Adjust the smoke temperature at the denitrification station according to actual needs to meet the denitrification requirements.

The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantive changes and substitutions made by those skilled in the art on the basis of the present invention fall within the scope of the present invention. Scope of protection claimed.

Claims (21)

1. A steam turbine unit based on series auxiliary regulation, including a power cylinder, which is any one of a high-pressure cylinder, a medium-pressure cylinder, and a low-pressure cylinder. The power cylinder is provided with a conventional steam inlet passage and a conventional pressure The stage group is characterized in that the power cylinder is also provided with at least one regulating pressure stage group, and the regulating pressure stage group is coaxially connected in series before the conventional pressure stage group, and each regulating pressure stage group There is at least one pressure stage inside. The pressure stage is composed of a stationary blade cascade located at the front end and a moving blade cascade located at the rear end. Each of the adjustment pressure stage groups has an independent adjustment steam inlet channel. The adjustment steam inlet channel The front end of the channel is connected with at least one regulating valve for controlling the steam flow on and off.
2. A steam turbine unit based on series auxiliary regulation according to claim 1, characterized in that the conventional pressure stage group or at least one of the regulated pressure stage groups adopts a full circumferential steam intake method, and no regulating stage is provided at the front end. .
3. A steam turbine unit based on series auxiliary regulation according to claim 1, characterized in that the static blade cascade in the frontmost pressure stage in the regulated pressure stage group farthest from the conventional pressure stage group is embedded On the inner cylinder of the power cylinder.
4. A steam turbine unit based on series auxiliary regulation according to claim 1, characterized in that the regulating pressure stage group farthest from the conventional pressure stage group is provided with a regulating stage, and the regulating stage is provided with at least Two nozzle sets.
5. A steam turbine unit based on series auxiliary regulation according to any one of claims 1 to 4, characterized in that the outlet of each adjustment pressure stage group is provided with a corresponding check door assembly, and the check door assembly The component is used to open when the corresponding regulating pressure stage group and its previous regulating pressure stage group are put into operation; when the corresponding regulating pressure stage group is not put into operation, and the following regulating pressure stage group or conventional pressure stage Closed when the group is put into operation.
6. A steam turbine unit based on series auxiliary regulation according to claim 5, characterized in that the outlet of each regulating pressure stage group is provided with an annular channel, and the check door assembly is located at the annular channel.
7. A steam turbine unit based on series auxiliary regulation according to claim 6, characterized in that the check door assembly includes a plurality of check door units arranged sequentially along the circumferential direction, and the check door unit includes a rotating shaft. and an opening and closing member, the opening and closing member can rotate along the rotation axis, and the axial projection of the opening and closing member in the closed state is composed of an inner edge line, a first edge line, a second edge line and an outer edge line. The irregular surfaces do not overlap each other. In the closed state, the inner edge lines of multiple opening and closing members are connected end to end to form a circle that coincides with the inner circle of the annular channel. The outer edge lines of the opening and closing components are connected end to end to form a closed figure.
8. A steam turbine unit based on series auxiliary regulation according to claim 7, characterized in that the outer edge line is a straight line, the closed figure is a polygon, the number of sides of the polygon is ≥ 3, and the rotation axis The central axis coincides with the axial projection of the edge of the polygon.
9. A steam turbine unit based on series auxiliary regulation according to claim 8, characterized in that the coverage area of the inscribed circle of the polygon is greater than or equal to the outer circle of the annular channel.
10. A steam turbine unit based on series auxiliary regulation according to claim 7, characterized in that the outer edge line is an arc, the closed figure is a circle, and the coverage area of the circle is greater than or equal to the annular shape. The outer circle of the channel.
11. A steam turbine unit based on series auxiliary regulation according to any one of claims 7 to 10, characterized in that the opening and closing member flips outward or inward along the rotation axis according to the front and rear pressure difference of the area where it is located. Turn inside out.
12. A steam turbine unit based on series auxiliary regulation according to claim 11, characterized in that the rotation angle of the opening and closing member flipped upward from the closed state to the open state is not greater than 135°.
13. A steam turbine unit based on series auxiliary regulation according to claim 12, characterized in that the check door unit further includes two positioning members, and the two positioning members are respectively used to fix or buffer the closed state and the The opening and closing member in the open state.
14. A thermal system based on series auxiliary regulation, characterized in that it includes a boiler and a steam turbine unit based on series auxiliary regulation according to any one of claims 1 to 13, the power cylinder is a high-pressure cylinder, and the The boiler is connected to the regulating steam inlet channel one by one through a piping system. The piping system is provided with a main steam valve for controlling the main steam flow of the boiler. The main steam valve is connected to each of the regulating steam inlets. At least one regulating valve is provided between the steam inlet channels.
15. A thermal system based on series auxiliary regulation according to claim 14, characterized in that the pipeline system includes a main steam pipeline and at least one branch steam pipeline network, and the main steam valve is located on the On the main steam pipeline, the branch steam pipe network is composed of several branch pipes, and each of the branch pipes is provided with a regulating valve.
16. A thermal system based on series auxiliary regulation according to claim 14, characterized in that it also includes a heat recovery system, the heat recovery system includes at least one adjustable heater, and at least one of the adjustment pressure stage groups. The steam outlet is connected to the adjustable heater through an air extraction pipe. The air extraction pipe is provided with a gas regulating valve assembly, and the adjustable heater is connected to the boiler.
17. An operation method of a thermal system based on series auxiliary regulation, which is characterized by including the following steps:

    According to the distance between each adjustment pressure level group and the first pressure level of the conventional pressure level group, from near to far, they are defined as the first adjustment pressure level group, the second adjustment pressure level group...the nth adjustment pressure level group, and the The adjustment steam inlet channels corresponding to the adjustment pressure stage group are defined in sequence as the first adjustment steam inlet channel, the second adjustment steam inlet channel... the nth adjustment steam inlet channel, and the conventional steam inlet channel is determined as the zeroth steam inlet channel;

    Divide the operating load of the thermal system into n+1 load intervals, and each load interval corresponds to one of the regulated steam inlet channels;

    According to the current operating load rate of the thermal system or according to the set target load rate, determine the target load interval that the thermal system needs to enter, and switch to the regulated steam inlet channel corresponding to the target load interval.
18. A method of operating a thermal system based on series auxiliary regulation according to claim 17, characterized in that:

    When the load of the thermal system is increased, the final adjustment steam inlet channel to be switched to is determined according to the load increase rate or the target load rate requirement;

    Directly open the final adjustment steam inlet channel, or;

    If there are other intermediate adjustment steam inlet channels between the final adjustment steam inlet channel and the current adjustment steam inlet channel, the intermediate adjustment steam inlet channels will be opened sequentially or simultaneously starting from the current adjustment steam inlet channel until the final adjustment steam inlet channel is opened. ;

    Determine whether the current load reaches the set value. If it does, gradually close other adjustment steam inlet channels except the final adjustment steam inlet channel.
19. A method of operating a thermal system based on series auxiliary regulation according to claim 17, characterized in that:

    When the load of the thermal system is reduced, the final adjustment steam inlet channel to be switched to is determined according to the load reduction rate requirement;

    Gradually close the regulating valve corresponding to the current regulating steam inlet channel;

    Determine whether the current load reaches the set value. If it does, gradually open the adjustment valve corresponding to the final adjustment steam inlet channel, and gradually close the adjustment valve corresponding to the current adjustment steam inlet channel.
20. The operating method of a thermal system based on series auxiliary regulation according to any one of claims 17 to 19, characterized in that when the load rate of the thermal system is lower than X% of the rated load, the air conditioning is turned on. A valve assembly is used to input the steam in the corresponding adjusted pressure stage group into the adjustable heater.
21. The operating method of a thermal system based on series auxiliary regulation according to any one of claims 17 to 19, characterized in that the boiler flue temperature is detected. If the boiler flue temperature is lower than the set temperature value, then Open the gas regulating valve assembly, and adjust the boiler flue temperature to be higher than the set temperature value by controlling the opening of the gas regulating valve assembly.

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