CN218820288U - A kind of adoption is reheated outside the stove and realizes the mechanical furnace decoupling and lowers 15794loss the power storage system - Google Patents

A kind of adoption is reheated outside the stove and realizes the mechanical furnace decoupling and lowers 15794loss the power storage system Download PDF

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CN218820288U
CN218820288U CN202221980318.7U CN202221980318U CN218820288U CN 218820288 U CN218820288 U CN 218820288U CN 202221980318 U CN202221980318 U CN 202221980318U CN 218820288 U CN218820288 U CN 218820288U
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steam
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林书成
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Abstract

Machine-furnace decoupling is realized by adopting reheating outside furnaceAnd is low
Figure DDA0003771096270000011
The energy-loss energy-storage thermoelectric system is characterized in that a main steam pipeline is connected with a high-pressure bypass pipeline; the external reheating bypass is arranged between the outlet of the high-pressure cylinder and the inlet of the intermediate pressure cylinder, and a decoupling reheater is mounted on the external reheating bypass in series; the reheating circulation pipeline is arranged between a hot end outlet of the reheater and a cold end inlet of the reheater, and the reheating circulation pipeline is connected with a decoupling reheater in series; the steam in the furnace external reheating bypass and the steam in the reheating circulation pipeline exchange heat in the decoupling reheater; a path of high-temperature steam is led out from a hot end outlet of the reheater and sent to an energy storage reheater to serve as a heat source, and the heat of the energy storage reheater is used for reheating the inlet steam of the low-pressure cylinder; the system simplifies the type selection and regulation of the ejector and improves the working safety of the high-pressure cylinder; flexible and high-parameter external steam and heat supply is provided; and the up-down peak regulation capability of the unit is obviously optimized.

Description

A kind of adoption is reheated outside the stove and realizes the mechanical furnace decoupling and lowers 15794loss the power storage system
Technical Field
The utility model belongs to thermal power factory thermoelectric decoupling zero field, concretely relates to adopt outside of stove reheat to realize machine stove decoupling zero and hang down
Figure BDA0003771096250000011
A thermoelectric system for the loss of energy.
Background
The existing mechanical furnace decoupling system can connect an ejector group with a high-pressure cylinder for steam exhaust and is used for ejecting the high-pressure cylinder for steam exhaust. There are two problems in that: 1. uncertain influences exist on a steam turbine when an injector group works in the operation of a power plant; 2. as the decoupling amplitude of the machine furnace is enlarged, the boosting ratio n of the ejector needs to be increased, the working condition of the ejector is deteriorated, and the decoupling of the machine furnace has a certain upper limit; 3. even if a part of decoupling area is abandoned and the n value of the ejector is controlled within a certain range, the change in the range still causes the instantaneous injection ratio u to fluctuate, the flow rate Ma of power steam caused by the fluctuation still causes the fluctuation of the flow rate Mb of the sucked steam, the airflow of each steam extraction point fluctuates, and a DCS control system needs to realize a complex control process.
Meanwhile, when the existing mechanical furnace decoupling system deals with the pure condensation working condition of the unit, the redundant hot re-steam after mechanical furnace decoupling is completely cooled and decompressed and enters a low-pressure cylinder,
Figure BDA0003771096250000012
the loss is too large and the efficiency is too low; and with the increase of the installed capacity of new energy, the thermal power plant not only needs to have the capacity of down peak regulation, but also needs to have the capacity of up peak regulation when the power grid is in short of electricity. But the existing machine furnace decoupling system cannot additionally provide peak-load regulation capacity for the machine set.
The existing energy storage technical route has the advantages of strong flexibility of battery energy storage, high energy efficiency, high manufacturing cost, limited service life and poor cost performance; the conventional molten salt energy storage adopts electric heat conversion, and a huge electric heating module is needed, so that the system cost is increased; on the other hand, the energy efficiency problem of thermoelectric conversion exists when the unit is in pure condensation working condition to release heat.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an adopt outside of the stove reheat to realize that the machine stove decoupling zero reaches lowly
Figure BDA0003771096250000013
And a power loss system. The solution of avoiding interference with the steam turbine is achieved by rearranging the ejector and the high-exhaust system. After the energy storage module is added, the up/down peak regulation capacity under the pure condensation working condition is solved. Can realize the decoupling of the mechanical furnace of the thermal power plant, the large parameter heat supply (steam) and the low/large parameter heat supply (steam)>
Figure BDA0003771096250000014
Energy is lost. The utility model discloses thoroughly solved security, the variable operating mode problem in the machine stove decoupling zero, stored energy/can the process all adopt the heat exchange mode simultaneously, and the initial investment of unit power is extremely low to can the process be with well steam exhaust carry out reheated mode and accomplish, there is not the cold junction loss, make the whole efficiency that the system stored the full cycle high.
Machine-furnace decoupling and low realization by adopting reheating outside furnace
Figure BDA0003771096250000021
The energy-loss-storage thermoelectric system comprises a main steam pipeline, a high-pressure bypass pipeline, a high-pressure steam turbine cylinder, a medium-pressure steam turbine cylinder, a boiler reheater and a decoupling reheater; the main steam pipeline is connected with the high-pressure bypass pipelineIs connected with a high-pressure cylinder of a steam turbine;
the method is characterized in that a high-pressure cylinder steam exhaust pipeline is connected to a cold end inlet of a boiler reheater; the hot end outlet of the reheater is connected with the intermediate pressure cylinder of the steam turbine through an intermediate pressure cylinder steam inlet pipeline;
the external reheating bypass is arranged between the outlet of the high-pressure cylinder and the inlet of the intermediate pressure cylinder, and a decoupling reheater is mounted on the external reheating bypass in series;
the reheating circulation pipeline is arranged between a hot end outlet of the reheater and a cold end inlet of the reheater, and the reheating circulation pipeline is connected with a decoupling reheater in series;
the steam in the external reheating bypass exchanges heat with the steam in the reheating circulating pipeline in the decoupling reheater;
a steam ejector system is arranged in the reheating circulation pipeline; the high-pressure bypass pipeline is connected with a power steam inlet of the steam ejector system; the reheating circulating pipeline is connected with a suction steam port of the steam ejector system; the steam exhaust port of the steam ejector system is connected with the cold end inlet of the reheater.
Further, the steam ejector system adopts a single or a plurality of steam ejectors; the plurality of steam ejectors form a steam ejector group in a series connection, parallel connection or series-parallel connection combination mode.
The system further comprises an energy storage reheating module, wherein the energy storage reheating module consists of an energy storage heat exchanger, a high-temperature molten salt tank and a low-temperature molten salt tank; an energy storage bypass pipeline is led out from a hot end outlet of the reheater and connected to a first inlet of the energy storage heat exchanger; a first outlet of the energy storage heat exchanger is connected to the low pressure cylinder through a steam supplementing pipeline; the fused salt in the energy storage heat exchanger exchanges heat with the introduced steam.
Furthermore, the first outlet of the energy storage heat exchanger is also connected to a reheating circulation pipeline through a reheating circulation steam return pipe.
Furthermore, the exhaust steam of the intermediate pressure cylinder is connected to a second inlet of the energy storage heat exchanger through an intermediate row reheating pipeline; and a second outlet of the energy storage heat exchanger is connected to the low pressure cylinder through a steam inlet pipeline.
Further, the high-temperature molten salt tank is also connected with a power grid, and the electric energy of the power grid outside or inside the plant is utilized to electrically heat the molten salt.
Furthermore, a hot section pressure regulating assembly is arranged on the steam inlet pipeline of the intermediate pressure cylinder, the hot section pressure regulating assembly has a pressure building and regulating function, the target pressure required by the hot end of the reheater is controlled, and the actual pressure of the reheated steam is higher than the reheating pressure corresponding to the load of the boiler.
Furthermore, the external reheating bypass is connected out from the high-pressure cylinder exhaust pipeline, and the external reheating bypass and the intermediate-pressure cylinder steam inlet pipeline are converged at the downstream of the hot section pressure regulating assembly.
Furthermore, the high-pressure bypass pipeline is also connected with a high-pressure bypass external steam supply pipeline to supply industrial steam to the outside, the high-pressure cylinder steam exhaust pipeline is connected with a high-pressure exhaust external steam supply pipeline to supply industrial steam to the outside, and the reheating circulating pipeline is connected with heat and then supplies industrial steam to the outside.
Furthermore, the high-pressure bypass pipeline is also connected with a high-side interconnection pipe of an adjacent unit, and the two adjacent units are interconnected through the high-side interconnection pipe of the adjacent unit and are used for interconnection and assistance in supplying steam during decoupling operation of the boiler.
Compared with the prior art, the beneficial effects of the utility model are that:
the high-pressure cylinder exhaust steam bypass is arranged, the high-pressure cylinder exhaust steam is led out, and the decoupling reheater outside the furnace is additionally arranged, so that the complete decoupling state of the machine furnace can be smoothly transited after the high-pressure cylinder exhaust steam reaches the limit.
The ejector group is positioned in the thermal recycling loop, so that the working condition of the ejector becomes simple; only the hot outlet pressure needs to be boosted to the inlet pressure, the boost ratio is very low and is a fixed value (< 1.2), and the ejector group selection and regulation are greatly simplified. The injector group is not associated with the high pressure cylinder, eliminating the indeterminate effect on the high pressure cylinder.
The system has no problem of step-up ratio after the ejector is put into operation, and because the high emission is not returned to the boiler reheater, the pressure of the boiler reheater is not restricted by the value of the characteristic coefficient N and can be higher than the corresponding value of the boiler load rate. Through the hot section air-vent valve, can artificially control the target pressure value of reheater hot section, reheat steam actual pressure can be higher than the reheat pressure that boiler load corresponds for the steam supply quality (pressure) of unit promotes greatly. Similarly, the injector n value is fixed, the variable working condition trend is single, the space for mutually adjusting the extracted steam of each path is extremely large, and the adaptability of external steam supply is enhanced. The power plant can greatly widen the industrial steam supply market by matching with the improvement of steam supply pressure and the improvement of steam quantity.
According to the system, the energy storage bypass is arranged on the middle-low pressure cylinder communicating pipe, heat is stored during decoupling, and secondary reheating is provided for low-pressure cylinder steam admission when the power grid requires more power generation, so that the up-down peak regulation capability with excellent cost performance is obtained. And an electric heater unit can be additionally arranged and the energy storage scale can be expanded, so that the peak regulation capability of the thermal power plant can be greatly enhanced.
Drawings
Fig. 1 is a system pipeline connection diagram.
In the figure: the system comprises a main steam pipeline 1a, a high-pressure bypass pipeline 1B, a high-pressure cylinder steam exhaust pipeline 1C, a reheater cold section inlet 1d, a reheater hot end outlet 1e, a decoupling reheating inlet pipeline 2, a decoupling reheating outlet pipeline 3, a decoupling reheater 4, a hot section pressure regulating assembly 5, an intermediate pressure cylinder steam inlet pipeline 6, a steam ejector steam exhaust pipeline 7, a reheating circulation inlet pipeline 8, a reheating circulation outlet pipeline 9, a steam ejector system 10, a high bypass external steam supply pipeline 11, a high exhaust external steam supply pipeline 12, a hot bypass external steam supply pipeline 13, an energy storage bypass pipeline 14, an energy storage heat exchanger 15, a peak-shifting steam supply pipeline 16, a reheating circulation steam return pipe 17, a high-temperature molten salt tank 18a, a low-temperature molten salt tank 18B, an peak-shifting intermediate steam exhaust pipeline 19, a peak-shifting steam inlet pipeline 20, an off-plant or in-plant power grid 21, a low and medium and low-pressure cylinder communicating pipe 22, a neighboring unit high bypass pipe 23, a power steam inlet A, a suction steam inlet B and a steam exhaust port C.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The technical scheme of the utility model, do not receive the restriction of power plant unit capacity.
The technical scheme of the utility model, do not receive the power plant's unit for newly-built or the restriction of unit that has operated.
The technical scheme of the utility model, do not receive the restriction that the factory unit participated in degree of depth thermoelectric decoupling zero and heat supply platform number.
The technical scheme of the utility model, do not receive the restriction of power plant unit steam parameter.
The technical scheme of the utility model, do not receive power plant unit combined heat and power generation or pure operating mode restriction of congealing.
The technical scheme of the utility model, do not receive the restriction of power plant's heat supply thermodynamic system.
The technical scheme of the utility model, do not receive energy storage working medium (fused salt, conduction oil, solid heat accumulation, phase transition heat-retaining etc.), energy storage re-heater pattern, position restriction.
Machine-furnace decoupling and low realization by adopting reheating outside furnace
Figure BDA0003771096250000041
The power loss and energy storage fire-electricity system and the method can realize complete decoupling of the unit, large-parameter heat supply (steam) and low/long on the premise of not transforming a main machine and not interfering a steam turbine>
Figure BDA0003771096250000042
Energy is lost. And the energy distribution among electricity, heat (steam) and storage is flexible and efficient, the high flexibility requirement of a power grid, a heat supply network and a steam network on thermal power can be better met, the heat supply/steam supply scale can be greatly enlarged, the consumption of new energy is increased, a power plant can be built into a comprehensive energy supply core (steam supply, heat supply, power supply, refrigeration and flexibility supply), the capacity and the electric quantity released by the comprehensive energy supply core can meet the requirement of more new energy sources for surfing the internet, the scale of energy storage construction is reduced, and great contribution is made to a double-carbon target.
The system can be called as a BERL system for short, and consists of three sub-modules:
1. arranging (or utilizing) an original Bypass pipeline (Bypass) on a high-pressure cylinder exhaust pipeline, and installing a steam-steam heat exchanger to form an External Reheater module (External Reheater);
2. a steam ejector group is adopted to construct a heat recycling module (regenerator Recycle), so that the flow balance of a boiler Reheater is realized;
3. realize low
Figure BDA0003771096250000043
The energy Storage is energy loss-Heat Storage (Low energy-Heat Storage), namely an energy Storage reheating module.
The external reheater module and the thermal recirculation module are configured simultaneously to achieve the decoupling function.
If the energy storage module adopts an electric heater mode, the energy storage/heat release process can be independently realized. The energy storage module is matched with the external reheater module and the thermal recycling module, so that the investment of the electric heater can be greatly saved, or the energy storage power of the system can be improved.
The three modules are matched, so that large-parameter heat supply, high-pressure steam supply and flexibility peak regulation can be simultaneously met, efficient thermal power peak regulation can be realized under a pure condensation working condition, and the method is a brand-new subversive technical scheme in the thermal power flexibility field.
As shown in figure 1, a boiler body and a steam turbine body are not modified, all auxiliary machines of the boiler do not need to be modified, and a tail flue does not need to be modified under low load. All rotating machines on the side of the steam turbine do not need to be transformed, a regenerative system needs to be properly changed to adapt to the problem of large water supply quantity and insufficient regenerative steam extraction quantity, the load rate of the steam turbine can be set according to power grid dispatching, the load of a boiler can be determined according to the sum of electric load and thermal load, and in the process, the unit can be smoothly transformed from a conventional extraction condensing state to a complete decoupling state of the turbine.
The system comprises a main steam pipeline 1a, a high-pressure bypass pipeline 1b, a high-pressure cylinder of a steam turbine and a boiler reheater;
the main steam pipeline 1a of the power plant is connected with the high-pressure bypass pipeline 1b, and the main steam pipeline of the power plant is connected with the high-pressure cylinder of the steam turbine. A part of the high-temperature and high-pressure main steam from the main steam line enters the high-pressure cylinder of the steam turbine, and the other part of the high-temperature and high-pressure main steam enters the high-pressure bypass line 1b.
And a steam exhaust pipeline 1c of a high-pressure cylinder of the steam turbine is connected to an inlet 1d of a cold section of the reheater. The high pressure cylinder exhaust pipeline is provided with a valve, and the valve is gradually closed until the valve is completely closed when the machine furnace is decoupled.
The high-pressure bypass pipeline 1b is also connected with a high-pressure bypass external steam supply pipeline 11 to supply industrial steam to the outside.
The high-pressure bypass pipeline 1b is also connected with a high-side interconnection pipe 23 of an adjacent unit, and two adjacent unit systems are interconnected through the high-side interconnection pipe 23 of the adjacent unit. High side steam of adjacent units are interconnected and communicated so as to solve the problem of insufficient power steam when the units are switched from a normal working condition to a decoupling working condition. In the decoupling starting initial stage of the single unit machine furnace, the working condition point crossing is realized by using the power steam from the adjacent unit, and after the single unit machine furnace is decoupled and operated, the power steam of the local unit is abundant, so that the decoupling starting of the adjacent unit can be reversely supported. And the interconnection and intercommunication of high side steam of adjacent units can also be used for solving the problem of insufficient pressure holding capacity of the high-pressure cylinder.
The high-pressure cylinder steam exhaust pipeline 1c provides industrial steam to the external steam supply pipeline 12.
The system also comprises a steam turbine intermediate pressure cylinder and an intermediate pressure cylinder steam inlet pipeline.
The hot end outlet 1e of the reheater is connected with the steam turbine intermediate pressure cylinder through an intermediate pressure cylinder steam inlet pipeline 6 and used for driving the steam turbine intermediate pressure cylinder to do work.
The steam inlet pipeline 6 of the intermediate pressure cylinder is sequentially provided with a hot section pressure regulating assembly 5, an intermediate pressure cylinder flow control valve and an intermediate pressure valve.
Steam at the outlet of the hot section of the reheater passes through the hot section pressure regulating assembly 5, the flow control valve of the intermediate pressure cylinder and the intermediate regulating valve, and enters the intermediate pressure cylinder after pressure (flow) adaptation.
The hot section pressure regulating component 5 tracks the requirement of heat and then on the external steam supply pressure to follow up, and can realize the heat and pressure higher than the corresponding heat and pressure of the boiler load factor through pressure-holding regulation, so that the external steam supply potential of the unit is larger.
The hot section pressure regulating assembly 5 adopts a pressure retaining valve, has a pressure retaining and regulating function, and establishes a required pressure difference between an inlet and an outlet of the front end and the rear end of the hot section pressure regulating assembly under a certain flow parameter to meet a target pressure required by the hot end of the reheater.
The hot section pressure regulating assembly can adopt a multi-pressure-relief valve parallel arrangement mode, 2 or 3 valves are used for obtaining accurate pressure difference regulation, and the calibers of the valves can be the same or different. For small-caliber pipelines, the hot section pressure regulating assembly can be realized by adopting a single valve.
The flow control valve of the intermediate pressure cylinder can control the steam admission Mm of the intermediate pressure cylinder, so that the Mm is matched with the steam admission Mh of the high pressure cylinder, and the axial thrust balance of the steam turbine is ensured. As the Mm and the Mh of the steam turbine have certain deviation-tolerance capability, the unit can be ensured to be within the range of safety margin.
Further included in the system is an external reheat bypass and a decoupled reheater 4.
The reheating bypass outside the furnace is arranged between the outlet of the high-pressure cylinder and the inlet of the intermediate pressure cylinder. The starting point of the reheating bypass 2 outside the furnace is on the exhaust pipeline of the high-pressure cylinder, and the end point is on the steam inlet pipeline of the intermediate-pressure cylinder.
A bypass connected to the high-pressure cylinder exhaust pipeline is connected to the intermediate-pressure cylinder steam inlet pipeline, and the junction end point of the furnace reheating bypass and the intermediate-pressure cylinder steam inlet pipeline is located at the downstream of the hot section pressure regulating assembly 5 and the intermediate-pressure cylinder flow control valve.
A valve is arranged on the reheating bypass outside the furnace. The external reheating bypass is provided with a decoupling reheater 4, and comprises an inlet pipeline 2 positioned on the upstream side of the decoupling reheater 4 and an outlet pipeline 3 positioned on the downstream side. The decoupling reheater 4 adopts a hairpin heat exchanger, partial or all high-pressure cylinder exhaust steam from a reheating bypass outside the furnace is subjected to shell pass of the hairpin heat exchanger through the inlet pipeline 2, and is merged into a medium-pressure cylinder steam inlet pipeline through the outlet pipeline 3 after being heated.
The external reheating bypass and the decoupling reheater 4 form an external bypass reheating module.
The bypass reheating module outside the furnace introduces the high-pressure cylinder exhaust steam which originally enters a boiler reheater by using a bypass, and the high-pressure cylinder exhaust steam is converged with the shunted partial hot steam after the high-pressure cylinder exhaust steam passes through the decoupling reheater 4 and completes the heated process, and then enters an intermediate pressure cylinder to do work and generate power.
The flow of the decoupling reheater 4 has a larger matching range, and can be designed according to high discharge full flow or partial flow so as to reduce the equipment cost.
Further included in the system is a reheat cycle line, steam ejector system 10.
The high pressure bypass line 1b is connected to the motive steam inlet a of the steam ejector system 10. A temperature and pressure reducing device is arranged on the high-pressure bypass pipeline 1b, and the main steam after being subjected to temperature and pressure reduction is used as power steam of the steam ejector;
the hot end outlet 1e of the reheater is connected with two pipelines, and one pipeline is connected to the intermediate pressure cylinder through the intermediate pressure cylinder steam inlet pipeline 6. The other path is connected with a suction steam port B of the steam ejector through a reheating circulating pipeline.
Steam from the reheat cycle line is drawn as a steam ejector.
The steam outlet C of the steam ejector is connected to the reheater cold-end inlet 1d via a steam exhaust line 7.
The decoupling reheater 4 is connected in series on the reheating circulating pipeline, the reheating circulating pipeline comprises an inlet pipeline 8 positioned on the upstream side of the decoupling reheater 4 and an outlet pipeline 9 positioned on the downstream side, the inlet pipeline 8 is connected to a tube pass of the decoupling reheater 4, the outlet pipeline 9 is connected to a suction steam port B, superheated steam in the reheating circulating pipeline is used for reheating high-pressure cylinder exhaust steam flowing through a shell pass of the decoupling reheater 4, and the superheated steam in the reheating circulating pipeline becomes low in temperature after passing through the decoupling reheater 4 and enters the suction steam port B of the ejector along the outlet pipeline 9.
A valve is arranged on the inlet pipeline 8. A desuperheater is mounted on the outlet line 9. The outlet line 9 is also connected to a hot external steam supply line 13 for supplying external process steam.
The reheat cycle line and the steam ejector constitute a hot reheat steam recycle module. The exhaust steam of the steam ejector ensures that the reheater inlet parameters meet the boiler requirements. Especially when the unit is in the pure decoupling zero operating mode of congealing, can artificially control the temperature that improves the ejector exhaust steam, reduce the exhaust steam flow, reduce the heat absorption capacity of boiler re-heater, optimize afterbody flue operating mode, improve desulfurization and denitration system and the air preheater operating mode when the boiler low-load.
The steam ejector system 10 can adopt a single or a plurality of steam ejectors, the plurality of steam ejectors form a steam ejector group through combination modes such as series connection, parallel connection or series-parallel connection, the adjustment and optimization of parameters such as an ejection ratio and the like are realized, variable working conditions are completed, and nozzles of the steam ejectors adopt fixed nozzles or adjustable nozzles.
The system further comprises an energy storage bypass pipeline 14 and an energy storage reheating module.
The energy storage reheating module is composed of an energy storage heat exchanger 15, a high-temperature molten salt tank 18a and a low-temperature molten salt tank 18 b. The energy storage heat exchanger 15 adopts a shell-and-tube heat exchanger, two ends of a tube pass of the heat exchanger are respectively connected with a high-temperature molten salt tank and a low-temperature molten salt tank, and molten salt flows in the tube pass and exchanges heat with steam introduced in the shell pass of the heat exchanger.
The energy storage reheating module can complete two different steam heat release processes and a steam heating process.
1) Steam exothermal process.
The exhaust pipe of the intermediate pressure cylinder is connected with the inlet pipe of the low pressure cylinder through the communication pipe 22 of the intermediate and low pressure cylinders.
An energy storage bypass pipeline 14 is led out from a reheater hot end outlet 1e and connected to a shell side first inlet of the molten salt heat exchanger. The shell side first outlet is connected to the upstream of the low-pressure cylinder communicating pipe 22 through the steam supplementing pipe 16.
The energy storage reheating module can realize the peak regulation function under the pure condensation working condition of the unit: at this time, the boiler is operated at the lowest steady combustion (for example, 30% THA), and the steam turbine is operated at the high and medium pressure cylinders (irrespective of the low pressure cylinder) with the minimum steam admission amount (for example, 5% THA), so as to reduce the unit power generation amount as much as possible. At the moment, all the high-pressure cylinder exhaust steam flows through the decoupling reheater, and enters the intermediate pressure cylinder after being heated.
An energy storage bypass pipeline 14 is arranged at a hot end outlet 1e of the reheater and goes to a low-pressure cylinder, an energy storage heat exchanger 15 is arranged in a conveying process, hot reheat steam flows out of a shell pass of the energy storage heat exchanger 15, is cooled, then enters a middle-low pressure cylinder communicating pipe through a pressure reducing valve of a lower peak regulation steam supplementing pipeline 16, then flows into the low-pressure cylinder, and is supplemented with steam for the low-pressure cylinder. With molten salt on the tube side of the heat exchanger, absorbing and storing hot re-steam
Figure BDA0003771096250000071
Can reduce the generating capacity as much as possible and store redundant plants>
Figure BDA0003771096250000072
And simultaneously, the steam inlet quantity of the low pressure cylinder is ensured to be larger than the safety flow.
The shell side first outlet is also connected to a reheating cycle outlet pipeline 9 through a reheating cycle steam return pipe 17, and is used for reintroducing part of the heat-exchanged and temperature-reduced steam into the reheating cycle.
In the steam heat release process, steam in a multi-waste heat reheating section generated by machine-furnace decoupling enters an energy storage reheater 15 through an energy storage bypass pipeline 14, the steam is divided into two paths after heat release and temperature reduction, one path of steam is supplemented to a low-pressure cylinder to ensure that the low-pressure cylinder does not blow air, and the other path of steam returns to an ejector suction inlet B to meet the requirement of heat recirculation flow. At the moment, the unit is in an extremely low power generation amount, and even can reach a rotary standby state (0 electric quantity is on line). While being redundant
Figure BDA0003771096250000073
Is stored in the molten salt.
2) And (4) a steam heating process.
In order to complete the steam heating process, the system constructs a bypass of a medium-low pressure communicating pipe: the low and medium pressure cylinder communicating pipe 22 is provided with a shutoff valve. The intermediate-row reheat line 19 leads out from the upstream of the intermediate-low pressure cylinder communicating pipe 22, and is connected to the shell-side second inlet of the accumulator heat exchanger 15. The second outlet of the shell side is connected with the downstream of the low-pressure cylinder communicating pipe 22 through the peak-shaving steam inlet pipeline 20. When the shutoff valve is in a closed state, the middle-row reheating pipeline 19 and the upper peak-regulating steam inlet pipeline 20 form a bypass of a middle-low pressure communicating pipe.
The steam heating function is realized by leading the middle exhaust steam into an energy storage reheater for heating through a middle exhaust reheating pipeline 19 and leading the middle exhaust steam into a low pressure cylinder through an upper peak-regulating steam inlet pipeline 20.
When the load of the power grid rises again, even when the power plant needs to provide peak output, the valve on the communication pipe 22 of the medium and low pressure cylinder is closed, the medium exhaust steam firstly enters the energy storage reheater through the medium exhaust reheating pipeline 19 to be heated, and then enters the low pressure cylinder through the peak load regulation steam inlet pipeline 20. The heat released by the molten salt reheats the centrally-discharged steam, so that the peak regulation function of the thermal power generating unit is realized.
This energy storage reheat module has the function of row's secondary reheat in, does not increase the cold end loss when exothermic, except heat dissipation loss, does not have other
Figure BDA0003771096250000082
At the expense of even higher efficiency than the battery energy storage.
The lower peak regulation steam supply pipeline 16 and the middle exhaust reheating pipeline 19 can be respectively and independently provided with pipelines, or can be combined into a bidirectional flow pipeline in part of pipe sections, internal steam reversing is carried out based on different working conditions, and holes of a middle and low pressure communicating pipe can be reduced. In order to meet the arrangement requirement of a power plant, the middle-low pressure communicating pipe can be connected with the middle-exhaust steam extraction pipeline without opening holes.
The high-temperature molten salt tank 18a can be connected with a power grid 21, electric heating is carried out on the molten salt by utilizing electric energy of the power grid outside or inside the plant, the high-temperature molten salt tank 18a can be provided with a large-capacity electric heater, and valley electricity of the power grid is absorbed, so that the up-down peak regulation space of the power plant is greatly expanded, and the comprehensive service benefit of the thermal power plant is greatly improved.
Example (b):
taking a certain 300MW subcritical unit as an example, the THA main steam quantity of the unit is 928t, and the output is 300MW.
The system operating parameters are shown in table 1 below:
TABLE 1
Figure BDA0003771096250000081
Figure BDA0003771096250000091
When the system is operated and regulated, the following four typical working conditions are provided:
operating condition 1): the boiler is 100 percent, the steam turbine is 50 percent, and the heat supply and steam extraction capacity of the system is outstanding.
Operating mode 2): the boiler is 100 percent, the steam turbine is 20 percent, and the heat supply and steam extraction capacity of the system is outstanding.
Working condition 3): the boiler is in stable combustion load (30% THA working condition), the unit is in normal power generation operation when the load is extremely low in pure coagulation working condition, and the stored energy is subjected to down peak regulation.
Operating condition 4): the furnaces are all at 100% tha conditions, the grid requires maximum peak-to-peak capacity (superissue), and the discharge can be up-regulated.
When the machine furnace is decoupled and supplies heat to the outside, such as working condition 1) and working condition 2).
Firstly, a bypass reheating module outside the furnace is started, part of high exhaust is led to enter a decoupling reheater 4, and the high exhaust is heated and then heated to return to a hot re-pipeline to enter an intermediate pressure cylinder.
The hot re-steam recirculation module is next activated. The through flow required by the boiler reheater is realized by injecting heat recirculation through a steam ejector: and part of the reheating hot section steam goes to an intermediate pressure cylinder, and part of the reheating hot section steam enters a recirculation pipeline through an inlet pipeline 8 and enters the decoupling reheater 4, and the introduced part of the reheating hot section steam is heated and discharged. Then spraying water in proper amount to reduce temperature. The power steam of the ejector is used for ejecting and sucking low-pressure steam, and the requirement of a boiler reheater is met.
At the moment, the front and rear hearths of the boiler are balanced, and the high and medium pressure cylinders of the steam turbine are also in a balanced state.
At the moment, the high-discharge pipeline has redundant steam, and the redundant hot re-steam in the hot re-circulation pipeline can be used for supplying heat (steam) to the outside.
Further, if the boiler load is not changed, the steam engine load is reduced. The decoupling range of the engine and the furnace is continuously enlarged, the steam inlet quantity of the steam turbine is continuously reduced, the external steam supply capacity of the system is increased, and sufficient industrial steam can be provided for the outside.
When the unit operates in the pure condensing working condition, such as working condition 3).
When the peak regulation is needed by the power grid, the boiler is reduced to the lowest stable combustion load (30%), the steam turbine operates according to the minimum steam inlet quantity, the hot re-steam after the decoupling heat exchanger is exhausted is sucked by the ejector and then is brought into the hot re-circulation, and the redundant hot re-steam enters the energy storage reheating module to store energy and supplement steam for the low-pressure cylinder, so that air blowing is not needed. At the moment, the unit is artificially controlled to reduce the generated energy, and the reheating and cooling section is simultaneously heatedThe temperature of the steam is improved, and the working condition of the tail flue of the boiler is optimized. And will be effective
Figure BDA0003771096250000101
Stored in molten salt.
During peak load shifting, the energy storage reheating module can be electrically heated by using the electric energy of an off-plant or in-plant power grid, so that the valley electricity of the power grid is consumed.
When the grid requires the power plant to provide a peak output, such as condition 4).
When the power grid needs the power plant to provide peak output, the valve on the middle and low pressure cylinder communicating pipe 22 is closed, the middle exhaust steam enters the energy storage reheating module to be heated and reheated and enters the low pressure cylinder to do work, and therefore the peak regulation function on the thermal power generating unit is achieved. The heat-releasing process is a reheating process and is originally stored
Figure BDA0003771096250000102
Can be converted into electricity. Stored in energy storage reheating module>
Figure BDA0003771096250000103
The low-pressure cylinder is heated to enter steam in the peak load section of the power grid, and the low-pressure cylinder is reheated, so that the peak regulation (super-generation) function of the unit can be realized.
During actual operation regulation and control, when the unit is in a cogeneration mode and needs to reduce peak, the unit operates in a decoupling and energy storage heat absorption mode: high bypass opening, putting a decoupling reheater and an ejector group into operation, and after thermal recycling is established, a boiler can be in high load and a front hearth and a rear hearth are balanced, and a steam turbine is in low load and high-medium pressure cylinder thrust balance; at the moment, the energy of the hot section of the boiler reheater is much abundant, and the redundant energy released to the decoupling reheater and the energy storage reheater is supplied to the outside for heat (steam).
When the unit is in pure condensing condition and needs to adjust peak, the unit operates in decoupling and energy storage heat absorption mode: the boiler operates at the lowest stable combustion load, the steam turbine enters steam according to the minimum allowable steam inlet quantity of the high and medium pressure cylinders, the steam of the hot section of the boiler reheater does not go to the medium pressure cylinder any more, the steam is divided into two parts, one part of the steam goes to the decoupling reheater and then is completely sucked by the ejector set to realize heat recycling; the other path enters an energy storage reheater, and after being cooled, all the energy storage reheater enters a low pressure cylinder, so that the flow of the low pressure cylinder is increased, and no blast is ensured;
when the unit needs to be peaked up (whether cogeneration or straight condensing), the unit is not decoupled and operates in an energy storage and heat release manner: the high bypass, the decoupling reheater and the ejector all exit the operation; the communication valve is closed, the exhaust steam of the intermediate pressure cylinder firstly flows through the energy storage reheater, and then enters the low pressure cylinder after being heated, which is equivalent to the reheating process of the inlet steam of the low pressure cylinder.
From the above table 1, it can be seen that the system has great significance for pure condensation working conditions: the energy storage module of the system has extremely high energy efficiency, and the cost performance of the energy storage heat exchanger is superior to that of the electric heater, so the system has extremely high economical efficiency.
Bypass reheat module outside stove, heat steam recirculation module, energy storage reheat module in this application system cooperate each other, realize powerful thermal-power flexibility function: the device can be used for large-parameter heat (steam) supply working conditions and can also realize the great peak regulation capacity of the unit when being used for pure condensation working conditions. In the system, the steam ejector group does not extract steam from the high-pressure cylinder, so that the dynamic safety problem of the steam turbine is greatly simplified, and the engineering risk is greatly reduced.
The system has the obvious advantages that:
1) Existing METE (utilizing main steam to direct high exhaust back to reheater) systems have one limiting capability: as the turbine to boiler load differential becomes larger and larger, the injector bank step-up ratio n continues to rise, with an upper limit (typically 1.5 times safer). This results in METE systems that are difficult to decouple in full regime, and the high bypass in this system does not return to the boiler reheater, and does not have this problem either.
2) The behaviour of the ejector group of the BERL system is much better than that of the METE system: the BERL system only needs to boost the hot outlet pressure to the inlet pressure, the boost ratio is low and is a fixed value (< 1.2), greatly simplifying injector bank selection.
3) The monitoring of the DCS on the unit becomes simple: the high exhaust of the steam turbine is superior to that of a steam turbine, and the high exhaust does not need to return to a boiler reheater, so that the greatest difficulty of decoupling the turbine and the boiler is overcome. When the load rate of the power grid on the unit is too low and the unit needs to be subjected to decoupling and input, the high side valve, the hot re-pressure valve and the opening of the flow regulating valve are only required to be regulated; the load of the boiler is adjusted in a follow-up mode, the flow variable working condition of the ejector is only changed, the process system does not involve too many safety problems, and the safety monitoring difficulty of the DCS on the unit is lower.
4) The model selection design of the ejector group is simpler: the working condition of the injector group becomes excellent, so that the matching of the injection parameters n-u becomes simple. Because the boosting ratio becomes narrower than the variable working condition, only the variable working condition of the flow needs to be considered, the variable working condition of the injector group is changed from multi-dimension to single-dimension, and the design and the model selection are simpler.
5) The steam supply capacity of the high side becomes strong: because the working condition of the ejector group becomes excellent, the consumption of the motive steam becomes small, and the steam supply flow at the high side is obviously improved.
6) The steam supply pressure of the hot steam is not limited by the load rate of the boiler: the heat in the new system is physically isolated from the high-level exhaust, the pressure of the heat is not limited by the high-level exhaust, the heat is in closed-loop self-circulation, and the pressure rise of the ejector group only needs to compensate the on-way resistance loss of the heat recirculation (generally, the pressure loss of the boiler reheater is 10% of the heat, namely, the ejector group n =1.11 can realize the recirculation, and the pressure loss of the decoupling reheater is considered and cannot exceed 1.2). At this time, the pressure of the reheater is no longer limited by the boiler-boiler decoupling relationship and may even be higher than the thermal repressurization pressure corresponding to the boiler load rate (for example, the boiler is operated at 50% tha, the steam turbine is operated at 20% tha, and the thermal repressurization pressure may still be set at 3.5MPa when the boiler is operated at 100% tha). This means that the pressure level of the heat supplying steam to the outside can be full pressure, so that the steam supplying radius of the power plant is greatly expanded, and the market development and application are facilitated.
The system also has the obvious advantages of safety, energy conservation and environmental protection:
compared with the existing system reconstruction, the method is harmless reconstruction: 1) The boiler and the steam turbine body do not need to be transformed, and only the pipeline needs to be changed. 2) The system is not subjected to irreversible transformation, and can be switched to a pre-transformation state through a system shutoff door; 3) The ejector, the decoupling reheater and the energy storage reheater adopted by the system have intrinsic safety;
specially designed "energy storage reheatThe device "enables the molten salt energy storage to have extremely high efficiency: decoupling of surplus machine-furnace at trough section of electric network
Figure BDA0003771096250000121
The low-pressure steam is stored and supplemented to the low-pressure cylinder steam inlet in the peak period, the low-pressure steam inlet is reheated, and the output of the low-pressure cylinder is improved. System based on double reheat due to cold side increment without heat release process with efficiency equivalent to "unit double reheat>
Figure BDA0003771096250000122
The efficiency is extremely high.
If the molten salt system is enlarged in scale and provided with an electrode heating device, a large amount of valley electricity in the power grid can be consumed, and the heat release process of the system is
Figure BDA0003771096250000123
The efficiency is extremely high, almost can compare favourably with chemical batteries, and the cost performance is far higher than that of the chemical batteries.
Finally, it should be noted that: the above description is only for the purpose of explanation and not intended to limit the present invention, and although the present invention has been described in detail, it will be apparent to those skilled in the art that the foregoing descriptions can be modified, or equivalents may be substituted for some of the technical features thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. Machine-furnace decoupling and low realization by adopting reheating outside furnace
Figure FDA0003771096240000011
The power loss and energy storage thermoelectric system comprises a main steam pipeline, a high-pressure bypass pipeline, a high-pressure turbine cylinder, a medium-pressure turbine cylinder, a boiler reheater and a decoupling reheater; the main steam pipeline is connected with the high-pressure bypass pipeline and the high-pressure cylinder of the steam turbine;
the method is characterized in that a high-pressure cylinder steam exhaust pipeline is connected to a cold end inlet of a boiler reheater; the hot end outlet of the reheater is connected with the intermediate pressure cylinder of the steam turbine through an intermediate pressure cylinder steam inlet pipeline;
the external reheating bypass is arranged between the outlet of the high-pressure cylinder and the inlet of the intermediate pressure cylinder, and a decoupling reheater is mounted on the external reheating bypass in series;
the reheating circulation pipeline is arranged between a hot end outlet of the reheater and a cold end inlet of the reheater, and the reheating circulation pipeline is connected with a decoupling reheater in series;
the steam in the external reheating bypass exchanges heat with the steam in the reheating circulating pipeline in the decoupling reheater;
a steam ejector system is arranged in the reheating circulation pipeline; the high-pressure bypass pipeline is connected with a power steam inlet of the steam ejector system; the reheating circulating pipeline is connected with a suction steam port of the steam ejector system; and a steam discharge port of the steam ejector system is connected with a cold end inlet of the reheater.
2. The method as claimed in claim 1 for achieving machine-furnace decoupling and low temperature with external reheating
Figure FDA0003771096240000012
The energy-loss-storage thermoelectric system is characterized in that the steam ejector system adopts a single or a plurality of steam ejectors; the plurality of steam ejectors form a steam ejector group in a series connection, parallel connection or series-parallel connection combination mode.
3. The method as claimed in claim 1 for achieving machine-furnace decoupling and low temperature with external reheating
Figure FDA0003771096240000013
The energy-loss-storage thermoelectric system is characterized by comprising an energy-storage reheating module, wherein the energy-storage reheating module consists of an energy-storage heat exchanger, a high-temperature molten salt tank and a low-temperature molten salt tank; an energy storage bypass pipeline is led out from a hot end outlet of the reheater and connected to a first inlet of the energy storage heat exchanger; a first outlet of the energy storage heat exchanger is connected to the low pressure cylinder through a steam supplementing pipeline; molten salt and channel in energy storage heat exchangerThe incoming steam produces heat exchange.
4. The method as claimed in claim 3 for achieving machine-to-furnace decoupling and low-to-furnace reheating with external reheating
Figure FDA0003771096240000014
The energy-loss-storage thermoelectric system is characterized in that the first outlet of the energy-storage heat exchanger is also connected to a reheating circulation pipeline through a reheating circulation steam return pipe.
5. The method as claimed in claim 3 for achieving machine-to-furnace decoupling and low-to-furnace reheating with external reheating
Figure FDA0003771096240000015
The power loss and energy storage thermoelectric system is characterized in that the exhaust steam of the intermediate pressure cylinder is connected to a second inlet of the energy storage heat exchanger through an intermediate row reheating pipeline; and a second outlet of the energy storage heat exchanger is connected to the low pressure cylinder through a steam inlet pipeline.
6. The method as claimed in claim 3 for achieving machine-to-furnace decoupling and low-to-furnace reheating with external reheating
Figure FDA0003771096240000016
The loss energy storage thermoelectric system is characterized in that the high-temperature molten salt tank is also connected with a power grid, and the electric energy of the power grid outside or inside the plant is utilized to electrically heat the molten salt.
7. The method as claimed in claim 1 for achieving machine-furnace decoupling and low temperature with external reheating
Figure FDA0003771096240000017
The loss energy storage thermoelectric system is characterized in that a hot section pressure regulating assembly is arranged on a steam inlet pipeline of the intermediate pressure cylinder, the hot section pressure regulating assembly has a pressure building and regulating function and controls target pressure required by a hot end of a reheater, and the actual pressure of reheated steam is higher than the reheat pressure corresponding to the load of a boiler.
8. The method of claim 7Machine-furnace decoupling and low realization by adopting reheating outside the furnace
Figure FDA0003771096240000021
The energy-loss-storage thermoelectric system is characterized in that an external reheating bypass is connected out from a high-pressure cylinder steam exhaust pipeline, and the external reheating bypass and a medium-pressure cylinder steam inlet pipeline are converged at the downstream of a hot section pressure regulating assembly.
9. The method of claim 1 for achieving machine-to-furnace decoupling and low-to-furnace reheating with external reheating
Figure FDA0003771096240000022
The high-pressure bypass pipeline is further connected with a high bypass external steam supply pipeline to supply industrial steam to the outside, a high-pressure cylinder steam exhaust pipeline is connected with a high exhaust external steam supply pipeline to supply industrial steam to the outside, and a reheating circulation pipeline is connected with heat and then supplies industrial steam to the outside.
10. The method as claimed in claim 1 for achieving machine-furnace decoupling and low temperature with external reheating
Figure FDA0003771096240000023
The high-pressure bypass pipeline is further connected with a high-side interconnection pipe of an adjacent unit, and the two adjacent units are interconnected through the high-side interconnection pipe of the adjacent unit and used for interconnection and assistance in steam supply during decoupling operation of the boiler. />
CN202221980318.7U 2022-04-27 2022-07-28 A kind of adoption is reheated outside the stove and realizes the mechanical furnace decoupling and lowers 15794loss the power storage system Active CN218820288U (en)

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