Deep peak regulation system configuration for adaptive operation of coal power unit

Abstract

The utility model provides a deep peak regulation system configuration for adaptive operation of a coal power unit, which is characterized in that a newly-added external steam cooler is additionally arranged at a water supply outlet of an existing final-stage high-pressure heater on a water supply pipeline, and a steam side inlet of the newly-added external steam cooler is connected with a pressurization module; steam lower than the target steam extraction pressure grade is introduced into an inlet of the pressurization module, and a steam side outlet of the newly-added external steam cooler communicates with a steam inlet of an existing final-stage high-pressure heater; feedwater is heated twice in a newly-added external steam cooler and an existing final-stage high-pressure heater, so that the temperature of feedwater entering a furnace of a unit is increased, and meanwhile, certain feedwater pressure is maintained, and the feedwater at an outlet of a coal economizer is kept at a certain supercooling degree; the denitration system of the unit can be continuously and stably put into operation under the working condition of deep peak regulation, the energy consumption of the unit is prevented from being greatly increased, and the operation economy of the unit is effectively improved.

Description

Technical Field

[0001] This utility model relates to the field of power generation technology, and in particular to a deep peak shaving system configuration for the adaptive operation of coal-fired power units. Background Technology

[0002] It belongs to the field of power generation technology, specifically the configuration of a deep peak-shaving system for the adaptive operation of generating units.

[0003] Currently, high-parameter, large-capacity, high-efficiency, and low-carbon ultra-supercritical units have become the mainstream choice for new thermal power plant units. However, among the existing units, there are approximately 1,000 subcritical units in the 300,000-600,000 kW range, with an installed capacity of about 350 million kW.

[0004] In recent years, the installed capacity and power generation of new energy sources have reached new highs. However, due to the uncertainty of power generation from new energy sources, traditional thermal power units, especially coal-fired power units, still need to play the role of basic backup power supply and flexible peak-shaving power supply in coordination with new energy power generation.

[0005] Taking a 300MW subcritical unit as an example, its high-pressure cylinder adopts a full-circumferential steam inlet method and is not equipped with a regulating stage. The power grid dispatch load range in this region is 40%-100% THA. However, with the rapid development of new energy sources, the power grid in this region has now notified the unit that it needs to operate under deep peak shaving, and the lower limit of load dispatch needs to be as low as 20%.

[0006] For subcritical units that need to participate in deep peak shaving operation, their high-pressure cylinders adopt a full-circumferential steam intake method and are not equipped with a regulating stage. The load variation range is 20%-100% THA, of which the deep peak shaving load range is 20%-30% THA or even lower. They will face the following problems:

[0007] (1) Under deep peak-shaving conditions, the economizer outlet flue gas temperature will be lower than the lower limit of the normal operating temperature of the denitrification catalyst, such as 300℃. The denitrification system will not be able to operate normally, and NO is expected to rise. X Emissions will surge and far exceed standard requirements, such as the emission limit being raised from 25 mg / Nm³. 3 The concentration of Nm2 surged to 200 mg / Nm3 3 The above levels far exceed the standard value of 50 mg / Nm³. 3 ).

[0008] (2) The boiler drum outlet temperature drops significantly, the main and reheat steam temperatures will decrease significantly, the unit energy consumption will increase significantly, and the operating economy will decrease significantly.

[0009] Therefore, how to maintain the continuous and stable operation of the denitrification system under deep peak shaving conditions for subcritical units, and avoid a significant increase in unit energy consumption and a significant decrease in operating economy, has become an urgent problem to be solved. Utility Model Content

[0010] The technical problem this invention aims to solve is how to maintain the continuous and stable operation of the denitrification system in subcritical units under deep peak shaving conditions, avoiding the defects of a significant increase in unit energy consumption and a significant decrease in operating economy. This invention provides a deep peak shaving system configuration for the adaptive operation of coal-fired power units.

[0011] The present invention solves the above-mentioned technical problems through the following technical solution:

[0012] This utility model provides a deep peak-shaving system configuration for the adaptive operation of a coal-fired power unit, comprising a boiler, a deaerator system, a high-pressure cylinder, an existing final-stage high-pressure heater, feedwater pipelines, and steam pipelines. The boiler includes an economizer, a steam drum, a superheater, a header, a downcomer, and water-cooled walls. The economizer, steam drum, and superheater are connected sequentially by pipelines. Water from the lower part of the steam drum flows through the downcomer to the header, is heated by the water-cooled walls, and then returns to the steam drum. The high-pressure cylinder adopts a full-circumference steam intake method and is not equipped with a regulating stage. The feedwater pipelines are sequentially configured with a deaerator system, an existing final-stage high-pressure heater, and a newly added external steam cooler. The feedwater outlet of the external steam cooler is connected to the boiler feedwater inlet; the steam pipeline includes a main steam pipeline connecting the boiler steam outlet and the high-pressure cylinder inlet, and an extraction steam pipeline connecting the high-pressure cylinder extraction steam outlet and the existing final-stage high-pressure heater inlet; a main steam throttling component is installed on the main steam pipeline, and an extraction steam isolation valve is arranged on the extraction steam pipeline; the steam-side inlet of the newly added external steam cooler is connected to a pressurization module, the inlet of the pressurization module is connected to steam with a pressure lower than the target extraction steam pressure level, and the steam-side outlet of the newly added external steam cooler is connected to the inlet of the existing final-stage high-pressure heater.

[0013] In this scheme, a new external steam cooler is added to the feedwater outlet of the existing final-stage high-pressure heater on the feedwater pipeline. The steam-side inlet of the new external steam cooler is connected to a booster module. The inlet of the booster module is connected to steam with a pressure lower than the target extraction pressure level. The steam-side outlet of the new external steam cooler is connected to the steam inlet of the existing final-stage high-pressure heater. The steam with a pressure lower than the target extraction pressure level is boosted by the booster module and first heats the feedwater in the new external steam cooler before heating it in the existing final-stage high-pressure heater. That is, the feedwater is heated twice, in the new external steam cooler and the existing final-stage high-pressure heater, to increase the unit's feedwater temperature. As the unit's feedwater temperature increases, the economizer inlet water temperature increases, which in turn increases the economizer outlet water temperature, and the economizer outlet flue gas temperature increases to meet the denitrification inlet flue gas temperature requirements.

[0014] Preferably, a steam compressor is installed in the pipeline of the booster module. The steam compressor is used to boost the steam entering the booster module that is below the target extraction pressure level, so that the steam below the target extraction pressure level is pressurized by the steam compressor to a pressure higher than the pressure of the final stage extraction steam of the high-pressure cylinder.

[0015] In this scheme, a steam compressor is installed in the pressurization module. The steam compressor pressurizes the steam that is below the target extraction pressure level and first heats the feedwater in the newly added external steam cooler. Then, the feedwater is heated in the existing final stage high-pressure heater. The steam that is below the target extraction pressure level is pressurized by the steam compressor to a pressure higher than the final stage extraction pressure of the high-pressure cylinder. This ensures that the steam pressure entering the newly added external steam cooler after being compressed by the steam compressor is higher than the final stage extraction pressure entering the existing final stage high-pressure heater. This ensures that the feedwater is heated to a higher temperature, thereby improving the boiler feedwater temperature of the unit under deep peak shaving conditions.

[0016] Preferably, when the steam from the steam-side outlet of the newly added external steam cooler enters the existing final stage high-pressure heater to heat the feedwater, the extraction steam isolation valve on the extraction steam pipeline of the existing final stage high-pressure heater is in the closed state, and the steam pressure at the steam-side outlet of the newly added external steam cooler is higher than the extraction steam pressure of the final stage of the high-pressure cylinder.

[0017] In this scheme, the extraction isolation valve is in the closed state, and the steam from the steam-side outlet of the newly added external steam cooler is sent into the existing final-stage high-pressure heater to replace the final-stage extraction steam of the high-pressure cylinder. The steam pressure at the steam-side outlet of the newly added external steam cooler is higher than the final-stage extraction steam pressure of the high-pressure cylinder, so that the steam pressure entering the existing final-stage high-pressure heater is higher than the final-stage extraction steam of the high-pressure cylinder, thereby further increasing the feedwater temperature entering the boiler.

[0018] Preferably, an additional steam extraction isolation valve is provided in the pipeline of the booster module, and the additional steam extraction isolation valve is located upstream of the steam compressor.

[0019] In this solution, a new extraction steam isolation valve is installed in the booster module and positioned upstream of the steam compressor. The new extraction steam isolation valve regulates the fluid flow rate entering the booster module. Furthermore, in the event of a malfunction in the steam compressor, the new external steam cooler, or other equipment, the new extraction steam isolation valve can be closed to prevent steam from entering the booster module, ensuring system safety and improving system operational flexibility.

[0020] Preferably, a circulating pump is installed in the downcomer connecting the steam drum and the header inside the boiler;

[0021] And / or, a heat exchanger is also provided in the pipeline of the booster module, the heat exchanger being located upstream of the steam compressor or between the steam compressor and the newly added external steam cooler.

[0022] In this scheme, a circulating pump is installed in the downcomer connecting the steam drum and the header to enhance the driving force of the working fluid circulation, allowing water in the lower part of the steam drum to flow smoothly through the downcomer to the header. A heat exchanger is installed in the pipeline of the booster module. Steam in the pipeline enters the heat exchanger to heat other working fluids, such as air, water, or coal, before entering the corresponding equipment. For example, after heat exchange, the heat exchanger is located upstream of the steam compressor. Steam below the target extraction pressure level first enters the heat exchanger to heat other working fluids, such as air, water, or coal, and then is pressurized by the steam compressor before entering the newly added external steam compressor. The feedwater is heated in the steam cooler, which reduces the steam temperature entering the steam compressor and relatively increases the steam flow rate of the newly added external steam cooler. The heat exchanger is set between the steam compressor and the newly added external steam cooler. Steam that is lower than the target extraction pressure level is pressurized by the steam compressor and then enters the heat exchanger to heat other working media, such as air, water, or coal, before entering the newly added external steam cooler to heat the feedwater. This reduces the steam temperature entering the newly added external steam cooler and relatively increases the steam flow rate of the newly added external steam cooler.

[0023] Preferably, the steam below the target extraction pressure level originates from the final stage extraction steam of the high-pressure cylinder, the inlet of the booster module is connected to the extraction steam pipeline via a pipeline, and the interface of the booster module connected to the extraction steam pipeline is located upstream of the extraction steam isolation valve.

[0024] In this scheme, the steam connected to the booster module at a pressure lower than the target extraction pressure level is the final stage extraction steam of the high-pressure cylinder of the unit. The booster module inlet is connected to the existing extraction steam pipeline of the final stage high-pressure heater. After being pressurized by the booster module, the final stage extraction steam of the high-pressure cylinder first heats the feedwater in the newly added external steam cooler, and then heats the feedwater in the existing final stage high-pressure heater to improve the feedwater temperature of the unit under deep peak shaving conditions. The interface of the booster module to the extraction steam pipeline is located upstream of the extraction steam isolation valve. The final stage extraction steam of the high-pressure cylinder is led out from the front end of the extraction steam isolation valve inlet. When the extraction steam isolation valve is closed, the final stage extraction steam of the high-pressure cylinder can enter the booster module, improving the flexibility of unit operation.

[0025] Preferably, the steam source below the target extraction pressure level is regenerative extraction steam or reheat system steam or superheater system steam in this unit or other units.

[0026] In this scheme, steam below the target extraction pressure level is optimized into reheat extraction steam or reheat system steam or superheater system steam in this unit or other units. Under the premise of ensuring that the steam compressor outlet steam pressure is higher than the final stage extraction steam of the high-pressure cylinder, the operation flexibility of this unit is improved.

[0027] Preferably, the main steam throttling assembly is a high-pressure cylinder inlet valve group or a regulating valve.

[0028] In this scheme, the main steam throttling component adopts a high-pressure cylinder inlet valve group or regulating valve to facilitate the adjustment of the pressure and flow rate of the main steam.

[0029] Preferably, the deep peak shaving system is configured to: throttle the main steam using the main steam throttling component to maintain a certain feedwater pressure and keep the economizer outlet feedwater at a certain degree of subcooling.

[0030] In this scheme, steam below the target extraction pressure level is pressurized by a booster module and then sequentially enters the newly added external steam cooler and the existing final-stage high-pressure heater to heat the feedwater. In order to increase the feedwater temperature of the unit under deep peak shaving conditions, the main steam is throttled by operating the main steam throttling component to maintain a certain feedwater pressure and keep the economizer outlet feedwater at a certain degree of subcooling.

[0031] Preferably, a throttling component is installed in the feedwater or steam pipeline system from the economizer outlet to the high-pressure cylinder inlet, and the throttling component is adjusted to maintain a certain feedwater pressure.

[0032] In this scheme, throttling components, such as regulating valves, can also be installed in the feedwater or steam pipeline from the economizer outlet to the high-pressure cylinder inlet. The throttling components can be adjusted to maintain a certain feedwater pressure, thereby keeping the economizer outlet feedwater at a certain degree of subcooling.

[0033] The positive and progressive effects of this utility model are as follows: A new external steam cooler is added to the feedwater outlet of the existing final-stage high-pressure heater on the feedwater pipeline, and the steam-side inlet of the new external steam cooler is connected to a booster module. The inlet of the booster module is connected to steam with a pressure lower than the target extraction pressure level, and the steam-side outlet of the new external steam cooler is connected to the steam inlet of the existing final-stage high-pressure heater. That is, the feedwater is heated twice, in the new external steam cooler and the existing final-stage high-pressure heater, to increase the feedwater temperature entering the boiler and at the same time maintain a certain feedwater pressure to keep the economizer outlet feedwater at a certain degree of subcooling. This enables the denitrification system of the unit to operate continuously and stably under deep peak-shaving conditions, avoids a significant increase in unit energy consumption, and effectively improves the economic efficiency of unit operation. Attached Figure Description

[0034] Figure 1This is a schematic diagram of a boiler feedwater heating system in the prior art.

[0035] Figure 2 This is a schematic diagram of the configuration of a deep peak-shaving system for the adaptive operation of a coal-fired power unit according to an embodiment of the present invention. Detailed Implementation

[0036] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0037] Figure 1 This is a schematic diagram of a boiler feedwater heating system in the prior art. The system includes a boiler, a deaerator system, a high-pressure cylinder, and an existing final-stage high-pressure heater. The boiler includes an economizer, a steam drum, a superheater, a header, a downcomer, and a water-cooled wall. The economizer, steam drum, and superheater are connected sequentially by pipelines. Water from the bottom of the steam drum flows through the downcomer to the header, is heated by the water-cooled wall, and then returns to the steam drum. The deaerator system includes a deaerator, a pre-pump, and a feedwater pump. The high-pressure cylinder uses a full-circumference steam inlet method and is not equipped with a regulating stage. The feedwater inlet of the existing final-stage high-pressure heater is connected to the feedwater outlet of the deaerator system, and the feedwater outlet of the existing final-stage high-pressure heater is connected to the feedwater inlet of the boiler. The steam outlet of the boiler is connected to the high-pressure cylinder through a main steam pipeline, and the steam inlet of the existing final-stage high-pressure heater is connected to the extraction port of the high-pressure cylinder through an extraction steam pipeline. A main steam throttling component is installed on the main steam pipeline, and an extraction steam isolation valve is arranged on the steam inlet pipeline.

[0038] This utility model provides a deep peak-shaving system configuration for the adaptive operation of coal-fired power units, such as... Figure 2As shown, the boiler, deaerator system, high-pressure cylinder, and existing final-stage high-pressure heater are included. The boiler comprises an economizer, steam drum, superheater, header, downcomer, and water-cooled walls. The economizer, steam drum, and superheater are connected sequentially via pipelines. Water from the lower part of the steam drum flows through the downcomer to the header, is heated by the water-cooled walls, and then returns to the steam drum. Wet saturated steam from the upper part of the steam drum enters the superheater and other heating surfaces for heating, ultimately obtaining main steam which enters the high-pressure cylinder to perform work. The high-pressure cylinder adopts a full-circumference steam inlet method and is not equipped with a regulating stage. The deaerator system, the existing final-stage high-pressure heater, and a newly added external steam cooler are sequentially installed in the feedwater pipeline. The external steam cooler's feedwater outlet is connected to the boiler feedwater inlet. The steam pipeline includes a main steam pipeline connecting the boiler steam outlet and the high-pressure cylinder inlet, and an extraction steam pipeline connecting the high-pressure cylinder extraction steam inlet and the existing final-stage high-pressure heater inlet. A main steam throttling component is installed on the main steam pipeline, and an extraction steam isolation valve is arranged on the extraction steam pipeline. The steam-side inlet of the newly added external steam cooler is connected to a booster module. The booster module inlet receives steam at a pressure lower than the target extraction steam pressure level, and the steam-side outlet of the newly added external steam cooler is connected to the inlet of the existing final-stage high-pressure heater. The target extraction steam pressure level can be understood as the steam that, if using the existing boiler feedwater heating system (i.e., without a booster module, directly enters the existing final-stage high-pressure heater to heat the feedwater to the required temperature and pressure), is the steam required to heat the feedwater to the required pressure.

[0039] Feedwater is sequentially delivered to the boiler feedwater inlet via the deaeration system, the existing final-stage high-pressure heater, and the newly added external steam cooler. Steam pressures below the target extraction pressure are boosted by a booster module and then used to heat the feedwater twice, once in the newly added external steam cooler and once in the existing final-stage high-pressure heater, to increase the unit's feedwater temperature. As the feedwater temperature increases, the economizer inlet water temperature rises, leading to an increase in the economizer outlet water temperature and ultimately, an increase in the economizer outlet flue gas temperature, meeting the denitrification inlet flue gas temperature requirements. Simultaneously, a certain feedwater pressure is maintained to keep the economizer outlet feedwater at a certain degree of subcooling. Ultimately, this ensures the continuous and stable operation of the denitrification system under deep peak-shaving conditions, preventing a significant increase in unit energy consumption and effectively improving the unit's operational economy.

[0040] Figure 2A high-pressure cylinder inlet valve group is installed on the main steam pipeline. Alternatively, other main steam throttling components, such as regulating valves, can be used to regulate the pressure and flow rate of the main steam. It is important to emphasize that when steam below the target extraction pressure level is pressurized in the booster module and first enters the newly added external steam cooler to heat the feedwater there, and then flows out of the new external steam cooler to enter the existing final-stage high-pressure heater to heat the feedwater, thus increasing the unit's feedwater temperature under deep peak-shaving conditions, the existing high-pressure cylinder inlet valve group can be used to throttle the main steam. The purpose is to maintain a certain feedwater pressure and keep the economizer outlet feedwater at a certain subcooling level to ensure normal unit operation. In other embodiments, throttling components, such as regulating valves, can be installed in the feedwater or steam pipeline system from the economizer outlet to the high-pressure cylinder inlet to maintain a certain feedwater pressure and keep the economizer outlet feedwater at a certain subcooling level.

[0041] like Figure 2 As shown, a steam compressor is installed in the booster module. The steam compressor pressurizes the steam that is below the target extraction pressure level and first heats the feedwater in the newly added external steam cooler. Then, it heats the feedwater in the existing final stage high-pressure heater. The steam that is below the target extraction pressure level is pressurized by the steam compressor to a pressure higher than the final stage extraction pressure of the high-pressure cylinder. This ensures that the steam pressure entering the newly added external steam cooler after being compressed by the steam compressor is higher than the final stage extraction pressure entering the existing final stage high-pressure heater. This ensures that the feedwater is heated to a higher temperature, thereby improving the boiler feedwater temperature of the unit under deep peak shaving conditions.

[0042] When the steam from the steam-side outlet of the newly added external steam cooler enters the existing final-stage high-pressure heater to heat the feedwater, the extraction isolation valve on the extraction steam pipeline of the existing final-stage high-pressure heater is in the closed state. The steam pressure at the steam-side outlet of the newly added external steam cooler is higher than the final-stage extraction steam pressure of the high-pressure cylinder. With the extraction isolation valve closed, the steam from the steam-side outlet of the newly added external steam cooler is sent into the existing final-stage high-pressure heater to replace the final-stage extraction steam of the high-pressure cylinder. The higher steam pressure at the steam-side outlet of the newly added external steam cooler than the final-stage extraction steam pressure of the high-pressure cylinder results in the steam pressure entering the existing final-stage high-pressure heater being higher than the final-stage extraction steam of the high-pressure cylinder, thereby further increasing the feedwater temperature entering the boiler.

[0043] like Figure 2As shown, a new steam extraction isolation valve is installed in the pipeline of the booster module. The new steam extraction isolation valve is located upstream of the steam compressor. The new steam extraction isolation valve can regulate the flow rate of fluid entering the booster module. In the event of failure of equipment such as the steam compressor or the new external steam cooler, the new steam extraction isolation valve can be closed to prevent steam from entering the booster module, thus ensuring the safety of system operation and improving the flexibility of system operation.

[0044] Although Figure 2 In this embodiment, the water in the boiler drum flows directly to the header through the downcomer. Of course, in other embodiments, a circulation pump can also be installed in the downcomer connecting the boiler drum and the header to enhance the driving force of the working fluid circulation, so that the water in the lower part of the drum can flow smoothly to the header through the downcomer. A heat exchanger can also be installed in the pipeline of the booster module. Steam in the pipeline enters the heat exchanger to heat other working media, such as air, water, and coal, before entering the corresponding equipment. For example, if the heat exchanger is located upstream of the steam compressor, steam below the target extraction pressure level first enters the heat exchanger to heat other working media, such as air, water, and coal, and then is pressurized by the steam compressor before entering the newly added external steam cooler to heat the feedwater. This can reduce the steam temperature entering the steam compressor and relatively increase the steam flow rate of the newly added external steam cooler. Alternatively, if the heat exchanger is located between the steam compressor and the newly added external steam cooler, steam below the target extraction pressure level is pressurized by the steam compressor before entering the heat exchanger to heat other working media, such as air, water, and coal, before entering the newly added external steam cooler to heat the feedwater. This can reduce the steam temperature entering the newly added external steam cooler and relatively increase the steam flow rate of the newly added external steam cooler.

[0045] like Figure 2As shown, the steam below the target extraction pressure level originates from the final stage extraction steam of the high-pressure cylinder. The inlet of the booster module is connected to the extraction steam pipeline via a pipe, and the interface of the booster module connecting to the extraction steam pipeline is located upstream of the extraction steam isolation valve. After being pressurized by the booster module, the final stage extraction steam of the high-pressure cylinder first heats the feedwater in the newly added external steam cooler, and then heats the feedwater in the existing final stage high-pressure heater to increase the feedwater temperature of the unit under deep peak shaving conditions. The interface of the booster module connecting to the extraction steam pipeline is located upstream of the extraction steam isolation valve. The final stage extraction steam of the high-pressure cylinder is led out from the front end of the extraction steam isolation valve inlet. When the extraction steam isolation valve is closed, the final stage extraction steam of the high-pressure cylinder can enter the booster module, improving the flexibility of unit operation. Of course, in other embodiments, the steam below the target extraction pressure level may be regenerative extraction steam or steam in the reheat system or superheater system of this unit or other units; it may also be a mixture of two or more of the aforementioned steam. Steam below the target extraction pressure level is optimized into reheat extraction steam or reheat system steam or superheater system steam in this unit or other units. Under the premise that the steam compressor outlet steam pressure is higher than the final stage extraction steam of the high-pressure cylinder, the operation flexibility of this unit is improved.

[0046] This utility model provides a deep peak-shaving system configuration for the adaptive operation of coal-fired power units. Under deep peak-shaving conditions, taking 20% ​​THA as an example: the feedwater temperature at the unit inlet can be increased to 75% THA or even 100% THA. With the increase in feedwater temperature, the economizer inlet water temperature increases, leading to an increase in economizer outlet water temperature, and the economizer outlet flue gas temperature also increases, meeting the denitrification inlet flue gas temperature requirements. While the economizer outlet water temperature increases, a certain feedwater pressure is maintained, ensuring a certain degree of subcooling at the economizer outlet. With the increase in feedwater pressure, the pressure of the steam-water mixture in the steam drum also increases, as does the wet saturated steam temperature at the top of the steam drum, and the main steam temperature also increases. With the increase in the ratio of main steam temperature, main steam quantity, and reheat steam quantity, both cold reheat steam and hot reheat steam temperatures increase, thus preventing a significant increase in unit energy consumption and effectively improving the unit's operational economy.

[0047] Taking a 300MW subcritical unit with a high-pressure cylinder that uses a full-circumferential steam inlet method and is not equipped with a regulating stage as an example, under the 20% THA condition.

[0048] The current system has the following parameters: main generator load 60MW, current final stage high pressure heater inlet steam pressure and temperature parameters 1.29MPa, 370℃, outlet feedwater pressure and temperature parameters 8.5MPa, 192℃, economizer outlet water temperature 211℃, subcooling 107.3℃, underenthalpy 521kJ / kg, economizer outlet flue gas temperature 272℃, and denitrification system cannot be put into operation.

[0049] In this embodiment, the main generator load is 60MW. The existing final stage extraction steam pressure and temperature parameters are 0.95MPa and 345℃. After being pressurized by the steam compressor and de-cooled by the newly added external steam cooler, the existing final stage high-pressure heater inlet steam pressure and temperature parameters are 3.7MPa and 401℃, and the outlet feedwater pressure and temperature parameters are 10.6MPa and 246℃. The water-side temperature rise of the newly added external steam cooler is 6℃. The economizer outlet water temperature is 273℃, the subcooling degree is 42.3℃, the under-enthalpy is 234.8kJ / kg, and the economizer outlet flue gas temperature is 339℃. The denitrification system is stably and continuously put into operation, and the unit's operating economy is improved due to the relative increase in feedwater temperature.

[0050] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A deep peak-shaving system configuration for adaptive operation of a coal-fired power unit, comprising a boiler, a deaerator system, a high-pressure cylinder, an existing final-stage high-pressure heater, feedwater pipelines, and steam pipelines, characterized in that: The boiler includes an economizer, a steam drum, a superheater, a header, a downcomer, and water-cooled walls. The economizer, steam drum, and superheater are connected sequentially via pipelines. Water from the bottom of the steam drum flows through the downcomer to the header, is heated by the water-cooled walls, and then returns to the steam drum. The high-pressure cylinder uses a full-circumference steam inlet and is not equipped with a regulating stage. A deaeration system, an existing final-stage high-pressure heater, and a newly added external steam cooler are sequentially installed in the feedwater pipeline. The feedwater outlet of the newly added external steam cooler is connected to the boiler feedwater inlet. The steam pipeline includes a main steam pipeline connecting the boiler steam outlet and the high-pressure cylinder inlet, and an extraction steam pipeline connecting the high-pressure cylinder extraction steam outlet and the existing final-stage high-pressure heater inlet. A main steam throttling component is installed on the main steam pipeline, and an extraction steam isolation valve is arranged on the extraction steam pipeline. A booster module is connected to the steam-side inlet of the newly added external steam cooler. Steam with a pressure lower than the target extraction steam pressure level is connected to the steam-side outlet of the newly added external steam cooler.

2. The deep peak shaving system configuration as described in claim 1, characterized in that, A steam compressor is installed in the pipeline of the booster module. The steam compressor is used to boost the steam entering the booster module that is below the target extraction pressure level, so that the steam below the target extraction pressure level is pressurized by the steam compressor to a pressure higher than the pressure of the final stage extraction steam of the high-pressure cylinder.

3. The deep peak-shaving system configuration as described in claim 2, characterized in that, When the steam from the steam-side outlet of the newly added external steam cooler enters the existing final stage high-pressure heater to heat the feedwater, the extraction steam isolation valve on the extraction steam pipeline is in the closed state, and the steam pressure at the steam-side outlet of the newly added external steam cooler is higher than the extraction steam pressure of the final stage of the high-pressure cylinder.

4. The deep peak-shaving system configuration as described in claim 3, characterized in that, The booster module is equipped with a new steam extraction isolation valve in its pipeline, and the new steam extraction isolation valve is located upstream of the steam compressor.

5. The deep peak-shaving system configuration as described in claim 4, characterized in that, Inside the boiler, a circulating pump is installed in the downcomer connecting the steam drum and the header; And / or, a heat exchanger is also provided in the pipeline of the booster module, the heat exchanger being located upstream of the steam compressor or between the steam compressor and the newly added external steam cooler.

6. The deep peak-shaving system configuration as described in claim 4, characterized in that, The steam below the target extraction pressure level originates from the final stage extraction of the high-pressure cylinder. The inlet of the booster module is connected to the extraction steam pipeline via a pipe, and the interface of the booster module connected to the extraction steam pipeline is located upstream of the extraction steam isolation valve.

7. The deep peak-shaving system configuration as described in claim 4, characterized in that, Steam sources below the target extraction pressure level are reheat extraction steam or reheat system steam or superheater system steam in this unit or other units.

8. The deep peak-shaving system configuration as described in claim 1, characterized in that, The main steam throttling assembly is a high-pressure cylinder inlet valve group or a regulating valve.

9. The deep peak-shaving system configuration as described in any one of claims 1-8, characterized in that, A throttling component is installed in the feedwater or steam pipeline from the economizer outlet to the high-pressure cylinder inlet.

Images