Hot air water supply flue gas and steam coupling deep peak regulation system

Abstract

The invention relates to a hot air water supply flue gas and steam coupling deep peak regulation system applied to the related field of thermal power generation, which is characterized in that a back pressure turbine and a secondary air heater are arranged in a turbine-boiler coupling heat regeneration system and are connected in series with a first high-pressure heater to form a new heat regeneration coupling system; the system extracts steam of a main steam system under low load, one part of the steam is used for replacing an electric drive pump or a fan, the other part of the steam is used for heating secondary air, coupling of hot air and steam is formed, quality and efficiency are improved, meanwhile, the temperature of main steam and reheated steam is increased, the temperature of feed water entering a boiler economizer is increased, and energy is saved. The inlet flue gas temperature of the SCR denitration system is increased, coupling of water supply flue gas and steam is formed, the low-load stable combustion capacity of the boiler is improved, the unit power supply coal consumption rate is reduced, unit industrial steam supply and thermoelectric decoupling are achieved, meanwhile, the load rate of dry-wet state conversion of a thermal power unit is reduced, and the thermal power generation efficiency is improved. And the unit operation economy and the unit service life are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a peak shaving system, in particular to a hot air feed water flue gas steam coupled deep peak shaving system applied to the field of thermal power generation. BACKGROUND

[0002] In recent years, with the rapid growth of the proportion of new energy (wind power, photovoltaic) power generation in the country, the flexibility of thermal power units as a peak shaving power source needs to be improved. The unit load needs to be frequently reduced to 15%-20% of the rated load or even lower for deep peak shaving. Under this working condition, a series of technical problems are highlighted. First, the unit power supply coal consumption increases significantly, for example, the power supply coal consumption of a 1000MW unit under 20%THA working condition can be as high as about 375g / kWh, which is much higher than the 285g / kWh under THA working condition. Second, the boiler furnace temperature decreases, the combustion stability deteriorates, and oil combustion is often needed to increase the operating cost and has safety hazards. Third, the flue gas temperature at the outlet of the economizer decreases, which is often lower than 280℃ under 30% rated load, which cannot meet the normal working temperature window of the SCR denitration catalyst, resulting in a decrease in denitration efficiency and an increase in ammonia escape rate, and may cause air preheater blockage. In addition, the main steam and reheat steam temperature deviates from the design value under low load, affecting the thermal economy of the unit and the safety of the steam turbine. Finally, the industrial heating extraction steam (usually from cold reheat steam) pressure also cannot meet the heating parameter demand under low load.

[0003] To solve the above problems, some improvement schemes are proposed in the prior art. For example, a steam turbine regenerative system is disclosed in Chinese Patent No. CN108843412B, which adopts a double small machine system composed of a back pressure turbine and a feed water pump turbine to use the back pressure turbine exhaust steam for regenerative heating, aiming to improve the cycle efficiency and simplify the regulation and control. However, this system mainly optimizes the regenerative process and does not involve using steam energy to improve the boiler air temperature and combustion stability, nor can it solve the problem of low SCR inlet flue gas temperature and industrial extraction steam parameter matching. For another example, a large and small double machine back pressure heating combined operation system and method are disclosed in Chinese Patent No. CN111677568A, which uses the surplus pressure head of the heating extraction steam to generate electricity and then supplies heat, realizing the cascade utilization of energy. However, the core of this scheme is to improve the heating economy, and its application scenario and functional design are focused on external heating, rather than the series of problems existing in the unit and boiler under deep peak shaving working condition, such as main / reheat steam temperature improvement and boiler combustion stabilization strengthening.

[0004] Therefore, the prior art lacks a comprehensive technical solution capable of systematically and integrally solving the problems of sharp increase of power supply coal consumption, difficulty in stable combustion of the boiler, too low SCR flue gas temperature, too low main and reheat steam temperature, high load rate during dry-wet state conversion of the unit and difficulty in guaranteeing industrial steam extraction when the thermal power unit is deeply regulated. SUMMARY

[0005] In view of the above prior art, the technical problem to be solved by the present application is that the power supply coal consumption sharply increases at low load of the thermal power unit, and the combustion of the boiler is unstable, and the inlet flue gas temperature of the SCR denitration system is also difficult to meet the standard.

[0006] To solve the above problems, the present application provides a hot air feed water flue gas steam coupling deep regulation system, comprising a main steam pipeline connected with a thermal power unit, a regulation unit connected with the middle part of the main steam pipeline, a steam turbine high-pressure cylinder connected with the end of the main steam pipeline, and a high-pressure feed water heating system, the high-pressure feed water heating system comprising a first high-pressure heater and a second high-pressure heater connected in series, the thermal power unit comprising a boiler and a superheated steam system, a reheated steam system, an economizer, an SCR denitration system and an air preheater arranged in sequence along the flue gas flow direction in the boiler, a combustion air box is installed on both sides of the furnace of the boiler, a first steam extraction pipeline is connected between the steam turbine high-pressure cylinder and the first high-pressure heater, a first steam extraction check valve is installed on the first steam extraction pipeline, the exhaust end of the steam turbine high-pressure cylinder is further connected with a second steam extraction pipeline and a second steam extraction pipeline to a reheater in parallel, the ends of the second steam extraction pipeline and the second steam extraction pipeline to the reheater are in communication with the reheated steam system and the second high-pressure heater, respectively, a second steam extraction check valve is installed on the second steam extraction pipeline, a main feed water pipeline is connected between the end of the first high-pressure heater and the economizer, and a high-pressure heater feed water pipeline is connected to the water inlet end of the second high-pressure heater. The peak shaving unit comprises a back pressure turbine and a secondary air heater, the back pressure turbine and the secondary air heater are connected in series through a back pressure turbine exhaust pipe between the inlet of the tube side of the secondary air heater, a superheated steam system extraction pipe is fixedly connected between the air inlet of the back pressure turbine and the middle part of the main steam pipe, a superheated steam extraction isolation adjusting valve is installed on the superheated steam system extraction pipe, an air pipe to the secondary air heater is connected between the shell side inlet of the secondary air heater and the outlet of the air preheater, an air pipe to the combustion air box is connected between the shell side outlet of the secondary air heater and the combustion air box, a secondary air heater exhaust pipe is connected to the tube side outlet of the secondary air heater, a pipe to the industrial steam extraction system connected with the industrial steam extraction system and a pipe to the high-pressure heater steam pipe connected with the high-pressure heater feed water heating system are connected in parallel at the end of the secondary air heater exhaust pipe, along the steam flow direction, an industrial steam extraction adjusting isolation valve and an industrial steam extraction check valve are installed in sequence on the pipe to the industrial steam extraction system, and a pipe to the high-pressure heater steam pipe is connected with a pipe to the high-pressure heater system steam check valve and a pipe to the high-pressure heater system adjusting isolation valve in sequence.

[0007] In the above hot air feed water flue gas steam coupling deep peak shaving system, under the low load operation condition of the unit, the stable combustion capacity of the unit is improved, and the dry-wet conversion load rate of the unit is reduced; the industrial steam source can be matched to achieve energy cascade utilization and efficient industrial heating, and the inlet flue gas temperature of the SCR denitration system is effectively improved, so that the unit can better adapt to flexible transformation and operation.

[0008] As a further improvement of the present application, the pipe to the high-pressure heater steam pipe is connected in parallel with a first high-pressure heater, temperature sensors are installed at the inlet of the reheat steam system, the economizer and the inlet of the SCR denitration system.

[0009] As a further improvement of the present application, the back pressure turbine directly drives the driven equipment, which is one or both of a pump and a fan.

[0010] As another improvement of the present application, an overspeed protection system is installed on the back pressure turbine, three speed sensors are installed on the rotor of the back pressure turbine, the three speed sensors are signal connected with the overspeed protection system, the overspeed protection system comprises a calculation module, an alarm unit, a steam diversion module, a quick emergency stop valve, a reverse brake module and a control center installed on the back pressure turbine, the quick emergency stop valve is installed on the superheated steam system extraction pipe and connected in series with the superheated steam extraction isolation adjusting valve, the overspeed protection system further comprises a flow meter and a pressure gauge installed at the outlet of the driven equipment and a recirculation valve installed on the driven equipment.

[0011] As a further improvement of the present application, the steam diversion module comprises a diversion pipe connected between the superheated steam system extraction pipe and the back pressure turbine exhaust pipe and an electromagnetic valve installed on the diversion pipe.

[0012] As a supplement to the improvement of the present application, the protection step of the overspeed protection system is: S11, the rotation speed of the back pressure machine rotor is monitored in real time through the rotation speed sensor, and the change rate of the data obtained by each rotation speed sensor is calculated in real time through the calculation module, and when the change rate of the data obtained by more than one rotation speed sensor exceeds the preset safety value, it indicates that the rotor of the back pressure machine is accelerating; S12, the flow and pressure change of the outlet of the driven equipment are monitored in real time through the flow meter and the pressure gauge, and when the flow or pressure suddenly drops, it indicates that the load is about to disappear; S13, when the rotor accelerates and the load is about to disappear at the same time, the alarm unit is triggered to alarm and make corresponding warning, and the control center automatically controls the opening degree of the overheat steam extraction isolation adjusting valve to decrease, so as to reduce the power source in advance and inhibit the rising trend of the rotation speed; S2, when the rotation speed of the back pressure machine rotor continues to rise and is greater than the rated rotation speed, the reverse brake module is triggered, so that the control center controls the recirculation valve on the driven equipment to be opened greatly, thereby instantaneously increasing the load of the back pressure machine, forcibly consuming the rotor kinetic energy, and forcing the rotation speed to fall back; S3, after the previous two protection steps, when the rotation speed of the back pressure machine rotor continues to rise, or the rotation speed is greater than or equal to 110% of the rated rotation speed, the control center controls the rapid emergency stop valve to be directly closed, thereby cutting off the steam source, and triggering the steam diversion module, so that the remaining steam in the pipeline is again shunted and directly crosses the back pressure machine to reach the secondary air heater, realizing rapid pressure relief of the back pressure machine and effectively eliminating the expansion work function of the residual steam; S4, finally, the control center controls the peak regulation unit to shut down until the abnormality is repaired and then starts.

[0013] As a supplement to the improvement of the present application, the overspeed protection system further includes a data storage module, the data of the rotation speed sensor, the pressure gauge and the flow meter are stored in the data storage module, and the data storage module further separately provides an abnormal data set, and the abnormal data set separately stores the abnormal data obtained by the rotation speed sensor, the pressure gauge and the flow meter and the time node corresponding to the abnormal data.

[0014] In summary, by arranging the back pressure turbine, the secondary air heater in the boiler-turbine coupled heat recovery system and connecting them with the first high pressure heater, a new heat recovery coupled system is formed. In the new system, an industrial steam extraction adjustment system is arranged to optimize the existing industrial steam system, reduce the coal consumption rate of the unit, realize the energy cascade utilization and efficient industrial heating of the unit; the system extracts steam from the main steam system at low load, part of which is used to replace the electrically driven pump or fan to reduce energy consumption, and the other part is used to heat the secondary air to form the coupling of hot air and steam, realize the upgrading and efficiency improvement, at the same time, improve the main steam temperature, the reheat steam, and the feedwater temperature entering the boiler economizer, and improve the inlet flue gas temperature of the SCR denitration system, form the coupling of feedwater flue gas and steam, and further improve the low load combustion stability of the boiler, realize the decoupling of industrial steam supply and thermal power of the unit, at the same time, reduce the load rate of the dry-wet state conversion of the thermal power unit, improve the economic efficiency and service life of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of the heat recovery system process of the first embodiment of the unit hot air feedwater flue gas steam coupling deep peak regulation technology of the present application; Figure 2 The figure is a schematic diagram of the traditional heat recovery system process; Figure 3 The figure is a system block diagram of the overspeed protection system installed on the back pressure turbine of the second embodiment of the present application; Figure 4 The figure is a schematic diagram of the rotational speed monitoring of the second embodiment of the present application; Figure 5 The figure is a schematic diagram of the steam diversion module of the second embodiment of the present application; Figure 6 The figure is a schematic diagram of the steam diversion module of the second embodiment of the present application when it is triggered; Figure 7 The figure is a schematic block diagram of the data storage module of the second embodiment of the present application; Figure 8 The figure is a flow chart of the overspeed protection system of the second embodiment of the present application.

[0016] Explanation of figure numbers: 1. boiler; 2. superheated steam system; 3. reheated steam system; 4. economizer; 5. SCR denitration system; 6. air preheater; 7. combustion air box; 8. steam turbine high pressure cylinder; 9. back pressure turbine; 10. secondary air heater; 11. first high pressure heater; 12. second high pressure heater; 13. superheated steam extraction isolation regulating valve; 14. industrial extraction check valve; 15. industrial extraction regulating isolation valve; 16. first stage extraction check isolation valve; 17. steam check valve to high pressure heater system; 18. regulating isolation valve to high pressure heater system; 19. second stage extraction check isolation valve.

[0017] a. main steam pipe; c. main feed water pipe; d. first stage extraction pipe; e. second stage extraction to reheater pipe; f. second stage extraction pipe; g. superheated steam system extraction pipe; h. back pressure turbine exhaust pipe; j. secondary air heater exhaust pipe; k. pipe to industrial extraction system; l. pipe to combustion air box; m. pipe to secondary air heater; n. pipe to high pressure heater steam pipe; o. high pressure heater feed water pipe. DETAILED DESCRIPTION

[0018] Two embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0019] First embodiment: Figure 1 A hot air feed water flue gas steam coupling deep peak shaving system is shown, which comprises a main steam pipe a connected with a thermal power generating unit, a peak shaving unit connected with the middle part of the main steam pipe a, a steam turbine high pressure cylinder 8 connected with the end of the main steam pipe a, and a high pressure heater feed water heating system, which comprises a first high pressure heater 11 and a second high pressure heater 12 connected in series with each other, the thermal power generating unit comprises a boiler 1 and a superheated steam system 2, a reheated steam system 3, an economizer 4, an SCR denitration system 5 and an air preheater 6 arranged in sequence along the flue gas flow direction in the boiler 1, one combustion air box 7 is installed on each side of the furnace of the boiler 1, a first stage extraction pipe d is connected between the steam turbine high pressure cylinder 8 and the first high pressure heater 11, a first stage extraction check isolation valve 16 is installed on the first stage extraction pipe d, a second stage extraction to reheater pipe e and a second stage extraction pipe f are connected in parallel with each other at the exhaust end of the steam turbine high pressure cylinder 8, the ends of the second stage extraction to reheater pipe e and the second stage extraction pipe f are communicated with the reheated steam system 3 and the second high pressure heater 12 respectively, a second stage extraction check isolation valve 19 is installed on the second stage extraction pipe f, a main feed water pipe c is connected between the end of the first high pressure heater 11 and the economizer 4, and a high pressure heater feed water pipe o is connected with the water inlet end of the second high pressure heater 12. The peak shaving unit comprises a back pressure machine 9 and a secondary air heater 10, the back pressure machine 9 is used to replace the electric drive to directly drive the pump or the fan, wherein the back pressure machine 9 can also be selected as a back pressure small steam turbine, the back pressure machine 9 and the secondary air heater 10 are connected in series through a back pressure machine exhaust pipe h between the pipe inlet of the secondary air heater 10 and the inlet of the air preheater 6, a superheated steam extraction pipe g is fixedly connected between the inlet of the back pressure machine 9 and the middle part of the main steam pipe a, a superheated steam extraction isolation adjusting valve 13 is arranged on the superheated steam extraction pipe g, a secondary air heater air pipe m connected to the secondary air heater 10 is connected between the shell inlet of the secondary air heater 10 and the outlet of the air preheater 6, a combustion air box 7 is connected between the shell outlet of the secondary air heater 10 and the combustion air box 7 through a combustion air box air pipe l, a secondary air heater exhaust pipe j is connected to the pipe outlet of the secondary air heater 10, the secondary air heater exhaust pipe j is connected to an industrial steam extraction system pipe k connected to the industrial steam extraction system and a high-pressure heater steam pipe n connected to the high-pressure heater heating system at the end, the high-pressure heater steam pipe n is connected to the first high-pressure heater 11 in parallel, along the steam flow direction, the industrial steam extraction adjusting isolation valve 15 and the industrial steam extraction check valve 14 are arranged on the industrial steam extraction system pipe k in sequence, the high-pressure heater steam pipe n is connected to the high-pressure heater system steam check valve 17 and the high-pressure heater system adjusting isolation valve 18 in sequence, in the above-mentioned hot flue gas steam coupling deep peak shaving system, under the low load operation condition of the unit, the stable combustion capacity of the unit is improved, the industrial steam extraction source is matched, the energy cascade utilization and the high-efficiency industrial heating are achieved, and the inlet flue gas temperature of the SCR denitration system is effectively improved, so that the unit is better adapted to the flexibility reconstruction and operation.

[0020] When the unit is working, the pressurized feed water at the outlet of the second high-pressure heater 12 enters the first high-pressure heater 11, a part of the steam source of the first high-pressure heater 11 is taken from the steam extraction of the steam turbine high-pressure cylinder 8 and enters the first high-pressure heater 11 through a first steam extraction pipe d, and a first steam extraction check isolation valve 16 arranged on the first steam extraction pipe d plays a role of isolation and prevents steam backflow; Part of the steam on the main steam pipe a enters the back pressure machine 9 through the superheated steam system extraction pipe g, and then heats the secondary air, the heated steam enters the first high-pressure heater 11 of the high-pressure heater heating system through the high-pressure heater steam pipe n, and heats the feed water in the first high-pressure heater 11, the steam is another part of the steam source of the first high-pressure heater 11, and the feed water, the steam passing through the steam turbine high-pressure cylinder 8 and the steam heated twice by the back pressure machine 9 and the secondary air heater 10 are heated together in the first high-pressure heater 11 and then enter the economizer 4 through the main feed water pipe c, thereby effectively improving the inlet feed water temperature of the economizer 4, improving the outlet flue gas of the economizer 4, increasing the thermal load of the boiler water wall region, and indirectly improving the low load stable combustion capacity; Wherein, the flue gas temperature at the outlet of the economizer 4 is improved, and the flue gas directly enters the SCR denitration system 5, that is, the flue gas temperature at the inlet of the SCR denitration system 5 is improved, and the flexible operation under the deep peak shaving of the unit is realized.

[0021] In addition, in the above process, the steam originally going to the high-pressure cylinder 8 of the steam turbine is partially branched to the back pressure turbine 9, so that the amount of steam entering the high-pressure cylinder 8 of the steam turbine is reduced, and the heat absorption capacity of the reheat steam system 3 is not weakened, thereby passively improving the temperature of the reheat steam entering the reheat steam system 3 along the two-stage steam extraction pipeline e to the reheater after passing through the high-pressure cylinder 8 of the steam turbine, effectively reducing the coal consumption of the unit for power supply.

[0022] At the same time, the steam passing through the back pressure turbine 9 enters the secondary air heater 10 along the back pressure turbine exhaust pipeline h, and the air flowing back from the air preheater 6 to the combustion air box 7 first passes through the secondary air heater 10 and is fully contacted with the heated steam to realize heat exchange, so that the temperature of the combustion air entering the boiler is greatly improved under the low load condition of the unit, the low load combustion stability of the boiler is enhanced, the carbon content of fly ash and slag is reduced, the combustion efficiency of the boiler is improved, and the coal consumption rate of the unit for power supply is further reduced, and the temperature of the main steam generated in the superheated steam system 2 is improved. In addition, the steam partially heated by the back pressure turbine 9 and the secondary air heater 10 is branched at the high-pressure heater steam pipeline n and the industrial steam extraction system pipeline k, part of which goes to the high-pressure heater feedwater heating system, and the other part of the steam can go to the original unit industrial steam extraction system along the industrial steam extraction system pipeline k for optimization matching, and the back pressure turbine 9 can drive the pump or fan according to the steam quality parameters to replace the electric drive, so as to improve the utilization rate of steam heat energy and reduce energy consumption.

[0023] The temperature sensors are installed at the inlets of the reheat steam system 3, the economizer 4 and the SCR denitration system 5, so that the temperature of the steam or gas entering the equipment during operation of the unit can be effectively monitored, and the working condition of the back pressure turbine 9 can be adjusted in time according to the temperature change, so that the peak shaving system can work stably, and the combustion stability of the generator set under the low load condition is improved.

[0024] In summary, by arranging the back pressure turbine, the secondary air heater and the first high pressure heater 11 in parallel in the boiler-turbine coupled heat recovery system to form a new heat recovery coupled system, and by setting an industrial steam extraction adjustment system in the system to optimize the matching with the existing industrial steam extraction system, the coal consumption rate of the unit is reduced, the energy cascade utilization and efficient industrial heating of the unit are realized, the steam in the main steam system is extracted at low load, a part of which is used to replace the power-driven pump or fan to reduce energy consumption, and the other part is used to heat the secondary air to form the coupling of hot air and steam, realize the upgrading and efficiency improvement, and improve the main steam temperature, the reheat steam, the feedwater temperature entering the boiler economizer, and the inlet flue gas temperature of the SCR denitration system to form the coupling of feedwater and flue gas, thereby improving the low load stable combustion capability of the boiler, realizing the decoupling of industrial steam supply and heat supply of the unit, and reducing the load rate of dry-wet state conversion of the thermal power unit, improving the economic efficiency of the unit operation and the service life of the unit.

[0025] Second embodiment: Since the improvement of the peak regulation system is mainly the setting of the back pressure turbine 9, and the back pressure turbine 9 is prone to overspeed abnormality in actual use, which not only affects the stable operation of the unit, but also causes the rotor blades to be broken after abnormal overspeed, resulting in great economic loss and safety hazards. Based on this problem, the present embodiment adds an overspeed protection system for the back pressure turbine 9 on the basis of the first embodiment, and the rest remains the same as the first embodiment.

[0026] Figure 3 As shown, the overspeed protection system is installed on the back pressure turbine 9, and three speed sensors are installed on the rotor of the back pressure turbine 9, for example, the three speed sensors are uniformly distributed at an interval of 120° around the rotor, the three speed sensors are signal connected with the overspeed protection system, the overspeed protection system includes a calculation module, an alarm unit, a steam diversion module, a quick emergency stop valve, a reverse braking module and a control center installed on the back pressure turbine 9, the quick emergency stop valve is installed on the superheated steam system extraction pipeline g and is connected in series with the superheated steam extraction isolation valve 13, and the overspeed protection system further includes a flow meter installed at the outlet of the driven device, a pressure gauge and a recirculation valve installed on the driven device.

[0027] As Figure 5 , the steam diversion module includes a diversion pipe connected between the superheated steam system extraction pipeline g and the back pressure turbine exhaust pipeline h and an electromagnetic valve installed on the diversion pipe.

[0028] As Figure 8 , the overspeed protection steps of the overspeed protection system for the back pressure turbine 9 are as follows: S1, early warning and prevention: S11, the rotation speed of the rotor of the back pressure machine 9 is monitored in real time through the rotation speed sensor, and the change rate of the data obtained by each rotation speed sensor is calculated in real time through the calculation module, such as Figure 4 When the change rate of the data obtained by more than one rotation speed sensor exceeds the preset safety value, it indicates that the rotor of the back pressure machine 9 is accelerating, and the preset safety value can be selected and set according to actual needs; S12, the flow rate and pressure change of the outlet of the driven equipment are monitored in real time through the flow meter and the pressure gauge, and when the flow rate or the pressure suddenly drops, it indicates that the load is about to disappear; S13, when the rotor accelerates and the load is about to disappear at the same time, the alarm unit is triggered to alarm and make corresponding warning, for example, prompting the staff through the sound and light alarm or voice broadcast that the rotor is accelerating or the load is about to disappear, and the control center automatically controls the opening degree of the overheat steam extraction isolation adjusting valve 13 to reduce, thereby reducing the power source in advance and inhibiting the rising trend of the rotation speed; S2, when the rotation speed of the rotor of the back pressure machine continuously rises and is greater than the rated rotation speed, the reverse brake module is triggered, so that the control center controls the recirculation valve on the driven equipment to be opened greatly, thereby instantaneously increasing the load of the back pressure machine 9, forcibly consuming the kinetic energy of the rotor, and forcing the rotation speed to fall back; S3, after the previous two protection steps, if the rotation speed of the rotor of the back pressure machine 9 continues to rise, or the rotation speed is greater than or equal to 110% of the rated rotation speed, the control center controls the quick emergency stop valve to be directly closed, thereby cutting off the steam source, such as Figure 6 At the same time, the steam diversion module is triggered, that is, the electromagnetic valve is opened at this time, so that the remaining steam in the pipeline is again shunted, and part of the residual steam can flow into the diversion pipe, thereby directly crossing the back pressure machine 9 to reach the secondary air heater 10, realizing the rapid pressure relief of the back pressure machine 9, and effectively eliminating the expansion work function of the residual steam; S4, finally, the control center controls the peak shaving unit to be shut down until the abnormality is repaired and then restarted.

[0029] As Figure 7 The overspeed protection system further includes a data storage module, the data of the rotation speed sensor, the pressure gauge and the flow meter are stored in the data storage module, and the data storage module further separately provides an abnormal data set, the abnormal data set separately stores the abnormal data obtained by the rotation speed sensor, the pressure gauge and the flow meter and the time node corresponding to the abnormal data. Through the record of the abnormal data, it is convenient for the staff to determine the time point of the abnormality and the related abnormal data when maintaining the back pressure machine 9, so as to formulate related maintenance measures according to the data and reduce the maintenance difficulty.

[0030] The above-mentioned embodiments of the present application are combined with the current actual demand, the protection scope is not limited to this, various changes made within the knowledge range of the person skilled in the art without departing from the concept of the present application still fall within the protection scope of the present application.

Claims

1. A hot air feed water flue gas steam coupled deep peak shaving system, characterized in that: The utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility model provides a kind of peak shaving unit and high-pressure feedwater heating system connected with main steam pipe (a) of thermal power generating unit, the utility ​ 2. The hot flue feedwater steam coupled deep peaking system of claim 1, wherein: ​ 3. The hot flue feedwater steam coupled deep peaking system of claim 1, wherein: ​ 4. The hot flue feed water steam coupled deep peaking system of claim 1, wherein: Along the steam flow direction, industrial steam extraction adjustment isolation valve (15) and industrial steam extraction check valve (14) are sequentially installed on the pipeline (k) leading to the industrial steam extraction system, and high-pressure heater steam pipeline (n) is sequentially connected with high-pressure heater steam check valve (17) and high-pressure heater adjustment isolation valve (18).

5. The hot flue feed water steam coupled deep peaking system of claim 1, wherein: The back pressure turbine (9) is provided with an overspeed protection system, three speed sensors are installed on the rotor of the back pressure turbine (9), the three speed sensors are signal connected with the overspeed protection system, the overspeed protection system comprises a calculation module, an alarm unit, a steam diversion module, a quick emergency stop valve, a reverse brake module and a control center installed on the back pressure turbine (9), the quick emergency stop valve is installed on the superheated steam extraction pipeline (g) and is connected in series with the superheated steam extraction isolation adjustment valve (13), the overspeed protection system further comprises a flow meter installed at the outlet of the driven equipment and a pressure gauge and a recirculation valve installed on the driven equipment.

6. The hot flue feedwater steam coupled deep peaking system of claim 5, wherein: The steam diversion module comprises a diversion pipe connected between the superheated steam extraction pipeline (g) and the back pressure turbine exhaust pipeline (h) and an electromagnetic valve installed on the diversion pipe.

7. The hot flue feed steam coupled deep peaking system of claim 6, wherein: The protection steps of the overspeed protection system are: S1, early warning and prevention: S11, the speed of the rotor of the back pressure turbine (9) is monitored in real time by the speed sensor, and the change rate of the data obtained by each speed sensor is calculated in real time by the calculation module, when the change rate of the data obtained by more than one speed sensor exceeds the preset safety value, it indicates that the rotor of the back pressure turbine (9) is accelerating; S12, the flow and pressure change at the outlet of the driven equipment are monitored in real time by the flow meter and the pressure gauge, when the flow or pressure suddenly drops, it indicates that the load is about to disappear; S13, when the rotor accelerates and the load is about to disappear at the same time, the alarm unit is triggered to alarm and appropriate warning is made, and the control center automatically controls the opening of the superheated steam extraction isolation adjustment valve (13) to be reduced; S2, when the speed of the rotor of the back pressure turbine continues to rise and is greater than the rated speed, the reverse brake module is triggered, so that the control center controls the recirculation valve on the driven equipment to be opened greatly, thereby instantaneously increasing the load of the back pressure turbine (9) and forcibly consuming the kinetic energy of the rotor, so as to force the speed to fall back; S3, after the above two protection steps, if the speed of the rotor of the back pressure turbine (9) continues to rise or the speed is greater than or equal to 110% of the rated speed, the control center controls the quick emergency stop valve to be directly closed, so as to cut off the steam source, and the steam diversion module is triggered at the same time, so that the remaining steam in the pipeline is again diverted and directly reaches the secondary air heater (10) across the back pressure turbine (9), thereby achieving rapid pressure relief for the back pressure turbine (9); S4, finally, the control center controls the peak shaving unit to be shut down until the abnormality is repaired and then restarted.

8. The hot flue feedwater steam coupled deep peaking system of claim 7, wherein: The overspeed protection system further comprises a data storage module, data of the rotation speed sensor, the pressure gauge and the flow meter are stored in the data storage module, and an abnormal data set is separately arranged in the data storage module, and the abnormal data set separately stores abnormal data obtained by the rotation speed sensor, the pressure gauge and the flow meter and a time node corresponding to the abnormal data.

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