A system and method for improving the RB working condition of the forced draft fan of a two-furnace-one-generator thermal power unit

Abstract

The present invention discloses a system and method for improving the RB operating condition of a blower in a two-boiler-one-unit thermal power unit. The output ends of the first blower and the second blower are both connected to one end of a first air supply main pipe, the other end of which is connected to a first boiler. The output ends of the third blower and the fourth blower are both connected to one end of a second air supply main pipe, the other end of which is connected to a second boiler. One end of a connecting pipe is connected to the first air supply main pipe, and the other end of the connecting pipe is connected to the second air supply main pipe. An electric regulating valve is provided on the connecting pipe. A first pressure transmitter and a second pressure transmitter are respectively provided on the first air supply main pipe and the second air supply main pipe. A PID controller is respectively connected to the first pressure transmitter, the second pressure transmitter, and the electric regulating valve. The present invention can effectively solve the blower RB problem caused by the failure of only one boiler blower in a two-boiler-one-unit unit.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control of thermal power plants, and in particular to a system and method for improving the operating condition of a blower RB of a two-boiler-one-unit thermal power plant. Background Art

[0002] The RB function allows the unit to rapidly respond to load commands and fuel levels in the event of an anomaly or failure in an auxiliary unit. The unit's primary automatic control systems work together to quickly and steadily reduce the unit's load to its maximum allowable output while ensuring continued safe operation. Most existing thermal power units are equipped with two blowers operating at 50% of their rated output as part of the unit's air supply system. If one blower fails and trips, losing its output capacity, the unit must shed 50% of its load and solid fuel at the fastest rate it can withstand, rapidly restoring stable combustion. In the thermal power industry, this failure process is referred to as air supply RNUBACK, commonly known as blower RB. There are two situations for the RB operating conditions of the blower of a two-boiler-one-unit thermal power unit: First, the blower of one of the boilers fails and trips, triggering the RB operating condition of the blower of the unit. In order to ensure the consistent steam quality before the gas valve, the other boiler with an intact blower system must also follow the boiler with the blower system failure, at the same speed and with guaranteed steam quality, and reduce the output to the target load until the load of the entire unit is reduced to 50% of the rated load; Second, one blower of each of the two boilers fails and trips at the same time, triggering the RB operating condition of the blower of the entire unit.

[0003] During a blower RB event in a two-boiler, one-unit unit, the unit load controller will automatically and rapidly shed the excess 50% of the load. The fuel systems of the two boilers will automatically and rapidly reduce the excess 50% of the fuel at a similar rate (related to the boiler's own characteristics, to ensure similar steam quality). Simultaneously, the primary air volume of each boiler will be reduced by 50% to match the fuel reduction rate. To maintain a constant furnace negative pressure, the furnace negative pressure control systems of the two boilers will also rapidly reduce the output of the induced draft fans of each boiler by 50%. The main function of the blower system is to help the pulverized coal entering the furnace fully complete the combustion process, releasing all of its energy into heat energy that is absorbed by the water-cooled walls. Furthermore, the reduction in the blower system output directly affects the stability of the furnace negative pressure. When a forced draft fan (RF) failure occurs, the first thing to change is the furnace negative pressure. This pressure plummets as the air supply system output decreases. Then, with the emergency operation of the furnace negative pressure control system, the induced draft fan output rapidly decreases to match the sudden decrease in air supply. However, the induced draft fan output cannot continue to decrease in response to the decrease in air supply. It must also account for the temporary, instantaneous increase in furnace negative pressure caused by the heat released by the combustion of excess fuel in the furnace that was not removed in time due to the sudden load reduction of the boiler. This process poses a significant challenge to the rapid response of the induced draft fan system. The rapid response of the induced draft fan is likely unable to keep up with the rapid change in furnace negative pressure, resulting in a unit trip due to excessive furnace negative pressure.

[0004] Secondly, it is reflected in the instability of combustion in the furnace. When the blower RB occurs, the fuel system quickly exits the pre-selected running grinding group system at a certain rate (the maximum rate is set according to the furnace energy characteristics) to adapt to the unit load instruction after the blower RB. As the grinding group system continues to exit, the fuel entering the furnace is rapidly reduced, and the heat released by the combustion of coal powder in the furnace is also getting less and less. However, while the boiler induced draft fan is reducing its output at its maximum speed, it has to maintain the violently fluctuating furnace negative pressure within the protection value. This causes the air flow field in the furnace to be extremely unstable, which in turn causes the temperature field in the furnace to change violently, which can easily cause the running grinding group in the furnace to lose ignition conditions and exit the operating state. Finally, the unit trips due to the furnace fire extinguishing signal.

[0005] After the blower RB occurs, due to insufficient output of the auxiliary combustion air supply system, a large area of unburned coal powder is retained in the furnace. However, the extremely unstable aerodynamic field at this time provides an opportunity for coal powder to be retained in the boiler tail flue. As time goes on, the unburned coal powder in the tail flue accumulates more and more. When it reaches a certain level, it will instantly explode in the tail flue, damaging the heat exchange area of the boiler tail flue, causing irreparable economic losses to the power generation company.

[0006] In a two-boiler, one-unit, master-controlled unit, consistent boiler outlet steam quality is a key parameter for safe operation. When the steam parameters at the outlets of the two boilers deviate beyond the permissible values for maintaining safe operation, the steam merging after the merging valve can cause severe vibration in the steam piping. In severe cases, this can rupture the steam piping, exposing high-temperature, high-pressure steam and causing significant damage to personnel and equipment. When a blower failure occurs in a two-boiler, one-unit unit, both boilers, while ensuring unit safety, must maintain steam quality before the merging valve within the permissible range to ensure smooth RB operation. However, reducing both boilers to the target load for RB operation at a consistent maximum speed places a significant strain on all auxiliary equipment and the professional skills of the boiler operators. Improper operation at any stage can lead to unplanned unit downtime and, worse still, equipment damage or personal injury, resulting in unimaginable human and financial losses for the power generation company.

[0007] The existing two-furnace-one-unit blower RB method has the following problems:

[0008] First, the simultaneous rapid reduction of 50% load on all auxiliary equipment in the entire unit has obviously put a lot of workload and mental stress on the operating personnel; the rapid response of the equipment is also a great test for the quality of the equipment materials, and the hidden damage caused to the equipment by multiple rapid load changes cannot be ignored.

[0009] Second, when the blower RB occurs, the secondary air volume in the furnace that assists the combustion of pulverized coal is reduced, causing a large area of unburned pulverized coal to remain in the furnace. However, the extremely unstable aerodynamic field at this time provides an opportunity for pulverized coal to remain in the boiler's tail flue. As time goes by, the unburned pulverized coal in the tail flue accumulates more and more. When it reaches a certain level, it will instantly explode in the tail flue, damaging the heat exchange area of the boiler's tail flue, causing irreparable economic losses to the power generation company.

[0010] Third, the blower RB causes the negative pressure in the furnace to fluctuate violently, which can even reach the boiler's limit protection value in an instant, or even exceed the limit value, causing unplanned shutdown of the unit; although the time of exceeding the limit protection value is not long, such frequent over-limit operation is also a great test for the material life of the boiler.

[0011] Finally, when the blower RB occurs, the loads of the two boilers change drastically at the same time, which poses a huge challenge to the operating personnel's ability to maintain the consistency of steam quality before the air valve. At the same time, the workload brought to the operating personnel is also obvious. If they are not careful, the unit may be shut down unplanned at best, and the unit equipment may be seriously damaged at worst, causing immeasurable economic losses to the power generation company. Summary of the Invention

[0012] In response to the problems existing in the prior art, the present invention provides a system and method for improving the RB operating conditions of the blower fan of a two-boiler-one-machine thermal power unit, which can effectively solve the blower fan RB problem caused by the failure of only one boiler blower in the two-boiler-one-machine unit. It is of great significance to improve the RB stability of the blower fan of the two-boiler-one-machine thermal power unit, extend the life of key boiler equipment, reduce the number of unplanned shutdowns of the unit's main auxiliary equipment due to the blower RB, and reduce maintenance and repair costs.

[0013] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0014] A system for improving the RB operating condition of a blower of a two-boiler-one-unit thermal power unit includes a first blower, a second blower, a first air supply main pipe, a first pressure transmitter, a first boiler, a third blower, a fourth blower, a second air supply main pipe, a second pressure transmitter, a second boiler, a connecting pipe, an electric regulating valve, and a PID controller. The output ends of the first blower and the second blower are both connected to one end of the first air supply main pipe, the other end of the first air supply main pipe is connected to the first boiler, the output ends of the third blower and the fourth blower are both connected to one end of the second air supply main pipe, the other end of the second air supply main pipe is connected to the second boiler, one end of the connecting pipe is connected to the first air supply main pipe, and the other end of the connecting pipe is connected to the second air supply main pipe. The electric regulating valve is arranged on the connecting pipe, the first pressure transmitter and the second pressure transmitter are respectively arranged on the first air supply main pipe and the second air supply main pipe, and the PID controller is connected to the first pressure transmitter, the second pressure transmitter, and the electric regulating valve, respectively.

[0015] Furthermore, the electric regulating valve is located in the middle of the connecting pipe.

[0016] Furthermore, the connection position between the connecting pipe and the first air supply main pipe is close to the output ends of the first air supply fan and the second air supply fan, and the connection position between the connecting pipe and the second air supply main pipe is close to the output ends of the third air supply fan and the fourth air supply fan.

[0017] Furthermore, the first pressure transmitter is close to the connection position between the connecting pipe and the first air supply main pipe, and the second pressure transmitter is close to the connection position between the connecting pipe and the second air supply main pipe.

[0018] Furthermore, the output ends of the first blower and the second blower are respectively provided with a first valve and a second valve, and the output ends of the third blower and the fourth blower are respectively provided with a third valve and a fourth valve.

[0019] A method for improving the operating condition of a blower RB of a two-boiler-one-unit thermal power plant, using the system, wherein when any one of the first blower, the second blower, the third blower, and the fourth blower fails, the blower RB of the two-boiler-one-unit thermal power plant is triggered, including:

[0020] The remaining three air supply fans are controlled to operate normally. The PID controller controls and adjusts the opening of the electric regulating valve on the connecting pipe according to the pressure of the first air supply main pipe collected by the first pressure transmitter and the pressure of the second air supply main pipe collected by the second pressure transmitter, so that the pressure of the first air supply main pipe and the pressure of the second air supply main pipe are in a balanced state, thereby making the first boiler and the second boiler tend to a stable state.

[0021] Furthermore, before the RB of the two-boiler-one-unit thermal power unit blower is triggered, if the unit load is greater than 75% of the rated load, the remaining three blowers are controlled to adjust their output to the maximum;

[0022] After the first boiler and the second boiler tend to be in a stable state, the remaining three blowers are controlled to operate at a rated load at a certain rate.

[0023] Furthermore, after the first boiler and the second boiler tend to be in a stable state, the remaining three blowers are controlled to operate normally, so that the unit load is maintained at 75% of the rated load.

[0024] Furthermore, after the first boiler and the second boiler tend to a stable state, the unit load is reduced to 50% according to a preset load change rate until any one of the air blowers corresponding to the boilers that are not connected to the faulty air blower stops safely. While reducing the unit load, the PID controller controls and adjusts the opening of the electric regulating valve on the connecting pipe according to the pressure of the first air supply main pipe collected by the first pressure transmitter and the pressure of the second air supply main pipe collected by the second pressure transmitter, so that the pressure of the first air supply main pipe and the pressure of the second air supply main pipe are in a balanced state.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects: when any of the first, second, third, and fourth blowers fails and the blower RB of a two-boiler, one-unit thermal power unit is triggered, the remaining three blowers are controlled to operate normally. A PID controller controls the opening of the electric regulating valve on the connecting pipe based on the pressure of the first air supply main pipe recorded by the first pressure transmitter and the pressure of the second air supply main pipe recorded by the second pressure transmitter, thereby balancing the pressure of the first air supply main pipe and the pressure of the second air supply main pipe, thereby stabilizing the first boiler and the second boiler. The present invention reduces the target value of the unit load command during the blower RB process of a two-boiler, one-unit thermal power unit, improves the rate of decrease of the two-boiler, one-unit load command, shortens the blower RB process time of the two-boiler, one-unit thermal power unit, and thus delays the process of withdrawing solid fuel from the unit's furnace. When a blower failure occurs in a two-boiler, one-unit thermal power plant, the unit load does not need to be rapidly reduced, nor do all of the unit's auxiliary equipment need to cooperate with the rapid reduction in unit load. Major unit parameters such as furnace negative pressure, main fuel quantity, main steam pressure, main steam temperature, and main feedwater flow rate no longer need to fluctuate significantly, thus preventing unexpected losses to the unit. With the help of the present invention, when a blower failure occurs in a two-boiler, one-unit thermal power plant, the operator only needs to calmly wait for the blower failure to complete and for the unit's operating conditions to return to normal. This present invention minimizes the likelihood of equipment damage in power generation companies during blower failure in two-boiler, one-unit thermal power plants, reduces the number of unplanned unit shutdowns caused by blower failure, and indirectly creates economic benefits for power generation companies. Based on the existing thermal power plant system hardware structure, this invention eliminates the need for complex hardware modifications and only requires a set of electric control valves to improve the amplitude of furnace negative pressure fluctuations, reducing the probability of unplanned unit shutdowns. It can even significantly reduce, or even eliminate, the occurrence of major accidents such as furnace implosion or explosions caused by unstable furnace negative pressure. Traditionally, the occurrence of RB in the blower of a two-boiler-one-unit thermal power unit can only be handled by the unit's coordinated control system, which quickly responds to rapid changes in the unit's load. However, when RB occurs in the blower of a two-boiler-one-unit thermal power unit, the present invention can substantially improve the actual situation of the lack of air volume through substantial means, while reducing the target load of the blower RB working condition of the two-boiler-one-unit thermal power unit, improving the coordinated control system to complete the blower RB process of the two-boiler-one-unit thermal power unit, and changing the history of the two-boiler-one-unit thermal power unit, which could only complete the blower RB process of the two-boiler-one-unit thermal power unit with the help of control means or human intervention. The present invention selects another boiler air supply system to compensate for the missing air volume of the unit because the two boiler air supply systems are consistent and the process is simple and easy to implement.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the specific embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 The present invention is a schematic diagram of the system structure for improving the RB working condition of the blower fan of a two-boiler-one-unit thermal power unit.

[0029] In the figure: 1-first air blower; 2-second air blower; 3-first valve; 4-second valve; 5-first pressure transmitter; 6-first boiler; 9-electric regulating valve; 10-PID controller; 11-third air blower; 12-fourth air blower; 13-third valve; 14-fourth valve; 15-second pressure transmitter; 16-second boiler; 17-first air supply main pipe; 18-second air supply main pipe; 19-connecting pipe. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] As a specific embodiment of the present invention, Figure 1 As shown, a system for improving the RB operating conditions of a two-boiler, one-unit thermal power unit blower includes a first blower 1, a second blower 2, a first air supply main pipe 17, a first pressure transmitter 5, a first boiler 6, a third blower 11, a fourth blower 12, a second air supply main pipe 18, a second pressure transmitter 15, a second boiler 16, a connecting pipe 19, an electric regulating valve 9, and a PID controller 10. The output ends of the first blower 1 and the second blower 2 are both connected to one end of the first air supply main pipe 17, and the other end of the first air supply main pipe 17 is connected to the first boiler 6. Preferably, the output ends of the first blower 1 and the second blower 2 are respectively provided with a first valve 3 and a second valve 4. The output ends of the third blower 11 and the fourth blower 12 are both connected to one end of the second air supply main pipe 18, and the other end of the second air supply main pipe 18 is connected to the second boiler 16. Preferably, the output ends of the third blower 11 and the fourth blower 12 are respectively provided with a third valve 13 and a fourth valve 14.

[0032] One end of the connecting pipe 19 is connected to the first air supply main pipe 17, and the other end of the connecting pipe 19 is connected to the second air supply main pipe 18. Preferably, the connection position of the connecting pipe 19 and the first air supply main pipe 17 is close to the output ends of the first air supply fan 1 and the second air supply fan 2, and the connection position of the connecting pipe 19 and the second air supply main pipe 18 is close to the output ends of the third air supply fan 11 and the fourth air supply fan 12.

[0033] The electric regulating valve 9 is arranged on the connecting pipe 19. Preferably, the electric regulating valve 9 is located in the middle position of the connecting pipe 19.

[0034] The first pressure transmitter 5 and the second pressure transmitter 15 are respectively arranged on the first air supply main pipe 17 and the second air supply main pipe 18. The first pressure transmitter 5 is used to collect the pressure of the first air supply main pipe 17, and the second pressure transmitter 15 is used to collect the pressure of the second air supply main pipe 18. Preferably, the first pressure transmitter 5 is close to the connection position between the connecting pipe 19 and the first air supply main pipe 17, and the second pressure transmitter 15 is close to the connection position between the connecting pipe 19 and the second air supply main pipe 18.

[0035] The PID controller 10 is connected to the first pressure transmitter 5, the second pressure transmitter 15, and the electric regulating valve 9, respectively. The PID controller 10 is used to control the opening of the electric regulating valve 9 on the connecting pipe 19 based on the difference between the pressure of the first air supply main pipe 17 and the pressure of the second air supply main pipe 18 collected by the first pressure transmitter 5 and the second pressure transmitter 15, so that the pressure of the first air supply main pipe 17 and the pressure of the second air supply main pipe 18 are in a balanced state, thereby stabilizing the first boiler 6 and the second boiler 16.

[0036] In the present invention, the PID controller is selected from Emerson's ovation system or Huaneng Ruiwo's HNICS-T316. The electric regulating valve 9 is selected from Sibos 2SA7321-2CE20-4BB4-Z or Shanghai Xingli LTCQ012.

[0037] The present invention provides a method for improving the RB operating condition of a two-boiler-one-unit thermal power plant. The method improves the RB operating condition of the blast fan of the two-boiler-one-unit thermal power plant by using compensation means. Taking the case where the first blast fan 1 connected to the first boiler 6 fails and trips, triggering the RB operating condition of the two-boiler-one-unit thermal power plant, while the other three blast fans are all normal, the effect of the system of the present invention on the RB operating condition of the two-boiler-one-unit thermal power plant is described as follows:

[0038] When the first blower 1 fails and trips, and the blower RB of the two-boiler-one-machine thermal power unit is triggered, the second boiler 16 does not need to trip a blower at the same time, and will not trigger the blower RB working condition like the first boiler 6. After the first blower 1 trips, the first valve 3 at the output end of the first blower 1 is closed, and the electric regulating valve 9 on the connecting pipe 19 between the first air supply main pipe 17 and the second air supply main pipe 18 is given a certain opening (the opening is related to the unit load before the blower RB occurs, and the greater the load, the greater the opening instruction), and the output of the remaining three blowers of the two boilers is adjusted to the maximum (when the unit load before RB occurs is greater than 75% of the rated load, the three blowers need to adjust the output to the maximum; when the unit load before RB occurs is less than 75% of the rated load, the output value of the three blowers is determined according to the unit load before RB occurs, and the greater the load, the greater the output of the three blowers), the PID controller 10 is based on At this time, the difference in pressure collected by the first pressure transmitter 5 and the second pressure transmitter 15 automatically adjusts the electric control valve 9 on the connecting pipe 19 to balance the pressure of the air supply main pipes of the two boilers (depending on the steam quality deviation before the steam valve at the outlet of the two boilers), and tries to make up for the air supply volume lost by the first boiler 6 due to the tripping of the first blower 1; after the two boilers gradually tend to a stable state, the three blowers are slowly turned down to the rated load at a certain rate according to the actual situation of the unit. During this process, the PID controller 10 always maintains the pressure of the air supply main pipes of the two boilers (i.e., the pressure of the first air supply main pipe 17 and the second air supply main pipe 18) within the deviation range allowed for safe operation of the unit. Under the improvement method of the present invention, when the blower RB of the two-boiler-one-machine unit is triggered, the air supply system of the entire unit can be regarded as a whole. In the case of losing the output of one blower, the air supply system of the entire unit is provided by the remaining three blowers. In other words, the entire unit still maintains 75% of the air supply capacity, so the blower RB target load of the two-boiler-one-machine thermal power unit can be completely optimized to 75% of the rated load. The unit RB target load should have been 50% of the rated load, but is now optimized to 75% of the rated load. The load change of the entire unit has been reduced from 50% to 25% of the rated load. The load change rate and the blower RB process time of the two-boiler-one-machine thermal power unit have been greatly improved.

[0039] After the two boilers slowly stabilize, the unit operator has two options: one, the unit continues to operate in this state (the unit load is approximately 75% of the rated load); the other, the operator reduces the unit load to 50% at a normal load change rate until any of the blowers connected to the other boiler (i.e., the second boiler 16) stops safely. During this process, the PID controller 10 always maintains the pressure of the two boilers' air supply main pipes in a balanced state by controlling the opening of the electric regulating valve 9 on the connecting pipe 19 until the other boiler (the second boiler 16) safely stops one blower. At this time, the electric regulating valve 9 on the connecting pipe 19 is controlled to be closed, and the PID controller 10 also stops working. This indicates that the improvement method of the present invention has successfully helped the two-boiler-one-unit thermal power unit complete the blower RB operating condition. If the blower RB of the two-boiler-one-unit thermal power unit is caused by the tripping of the other three blowers, the process is the same as the above blower RB process.

[0040] Example

[0041] like Figure 1 As shown, taking the case where the first blower 1 connected to the first boiler 6 fails and trips, triggering the blower RB of the two-boiler-one-unit thermal power unit, and the unit operates at 100% rated load before RB is triggered, and the other three blowers are normal as an example, the role of this pressure compensation system in the blower RB process of the two-boiler-one-unit thermal power unit is described.

[0042] When the first blower 1 trips due to a fault and the blower RB of the two-boiler-one-machine unit is triggered, the second boiler 16 does not need to trip a blower at the same time, and will not trigger the blower RB working condition like the first boiler 6. After the first blower 1 trips, the first valve 3 at the output end of the first blower 1 is closed, and the electric regulating valve 9 on the connecting pipe 19 between the first air supply main pipe 17 and the second air supply main pipe 18 is directly opened to 80% (a certain adjustment means is reserved), and the remaining three blowers of the two boilers are adjusted to maximum output (for general blower selection, the maximum output is greater than 50% of the rated load). At this moment, the PID controller 10 automatically adjusts the electric regulating valve 9 on the connecting pipe 19 based on the pressure difference between the first pressure transmitter 5 and the second pressure transmitter 15, so that the pressure deviation of the air supply main pipe of the two boilers is within 0.5 kPa, and the air supply volume lost by the first boiler 6 due to the tripping of the first air blower 1 is compensated as much as possible. After the two boilers gradually stabilize, the three air blowers are gradually reduced to the rated load at a rate of 1% / min according to the actual situation of the unit. During this process, the PID controller 10 always maintains the pressure of the air supply main pipe of the two boilers within 0.5 kPa. Under the improved method of the present invention, after the air blower RB of the two boilers and one unit is triggered, the air supply system of the entire unit can be regarded as a whole. In the event of the loss of the output of one air blower, the air supply system of the entire unit is provided by the remaining three air blowers. In other words, the entire unit still maintains 75% of its air supply capacity. Therefore, the target load of the air blower RB of the two-boiler-one-unit thermal power unit can be fully optimized to 75% of the rated load. At this point, the unit operator has two options: one, the unit continues to operate normally at 75% of the rated load; the other, the operator safely reduces the unit load to 50% at a rate of 1% of the rated load per minute until any blower of the other boiler (the second boiler 16) stops safely. During this process, the PID controller 10 always maintains the pressure of the two boilers' air supply main pipes within 0.5kPa by controlling the opening of the electric regulating valve 9 on the regulating connecting pipe 19 until the other boiler (the second boiler 16) safely stops one blower. At this time, the electric regulating valve 9 on the regulating connecting pipe 19 is in a closed state, and the PID controller 10 also stops working. It is characterized that the improvement method of the present invention successfully helps the two-boiler-one-unit thermal power unit to complete the blower RB operating condition.

[0043] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for improving the RB working condition of the blower of a two-boiler-one-unit thermal power unit, characterized in that: The method is implemented by using a system for improving the RB working condition of a blower of a two-boiler-one-unit thermal power unit. The system comprises a first blower (1), a second blower (2), a first air supply main pipe (17), a first pressure transmitter (5), a first boiler (6), a third blower (11), a fourth blower (12), a second air supply main pipe (18), a second pressure transmitter (15), a second boiler (16), a connecting pipe (19), an electric regulating valve (9) and a PID controller (10). The output ends of the first blower (1) and the second blower (2) are both connected to one end of the first air supply main pipe (17), the other end of the first air supply main pipe (17) is connected to the first boiler (6), the output ends of the third blower (11) and the fourth blower (12) are both connected to one end of the second air supply main pipe (18), the other end of the second air supply main pipe (18) is connected to the second boiler (16), and one end of the connecting pipe (19) is connected to the second boiler (16). The first end of the connecting pipe (19) is connected to the first air supply main pipe (17), the other end of the connecting pipe (19) is connected to the second air supply main pipe (18), the electric regulating valve (9) is arranged on the connecting pipe (19), the first pressure transmitter (5) and the second pressure transmitter (15) are respectively arranged on the first air supply main pipe (17) and the second air supply main pipe (18), the PID controller (10) is respectively connected to the first pressure transmitter (5), the second pressure transmitter (15) and the electric regulating valve (9); the electric regulating valve (9) is located in the middle position of the connecting pipe (19); the connection position of the connecting pipe (19) and the first air supply main pipe (17) is close to the output end of the first air supply fan (1) and the second air supply fan (2), and the connection position of the connecting pipe (19) and the second air supply main pipe (18) is close to the output end of the third air supply fan (11) and the fourth air supply fan (12); When any one of the first blower (1), the second blower (2), the third blower (11) and the fourth blower (12) fails and the blower RB of the two-boiler-one-unit thermal power unit is triggered, the method includes: The remaining three air supply fans are controlled to operate normally, and the PID controller (10) controls and adjusts the opening of the electric regulating valve (9) on the connecting pipe (19) according to the pressure of the first air supply main pipe (17) collected by the first pressure transmitter (5) and the pressure of the second air supply main pipe (18) collected by the second pressure transmitter (15), so that the pressure of the first air supply main pipe (17) and the pressure of the second air supply main pipe (18) are in a balanced state, thereby making the first boiler (6) and the second boiler (16) tend to a stable state; After the first boiler (6) and the second boiler (16) tend to be in a stable state, the unit load is reduced to 50% according to a preset load change rate until any one of the blowers corresponding to the boilers not connected to the failed blower is safely stopped. While reducing the unit load, the PID controller (10) controls and adjusts the opening of the electric regulating valve (9) on the connecting pipe (19) based on the pressure of the first air supply main pipe (17) collected by the first pressure transmitter (5) and the pressure of the second air supply main pipe (18) collected by the second pressure transmitter (15), so that the pressure of the first air supply main pipe (17) and the pressure of the second air supply main pipe (18) are in a balanced state.

2. The method for improving the RB working condition of the blower of a two-boiler-one-unit thermal power plant according to claim 1, characterized in that: The first pressure transmitter (5) is close to the connection position between the connecting pipe (19) and the first air supply main pipe (17), and the second pressure transmitter (15) is close to the connection position between the connecting pipe (19) and the second air supply main pipe (18).

3. The method for improving the RB working condition of the blower of a two-boiler-one-unit thermal power plant according to claim 1, characterized in that: The output ends of the first blower (1) and the second blower (2) are respectively provided with a first valve (3) and a second valve (4), and the output ends of the third blower (11) and the fourth blower (12) are respectively provided with a third valve (13) and a fourth valve (14).

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