Energy gradient utilization method for low-pressure cylinder micro-output combined high-back-pressure transformation

Abstract

The invention provides an energy gradient utilization method for low-pressure cylinder micro-output combined high-back-pressure transformation, and belongs to the technical field of thermoelectric decoupling. A device comprises a first intermediate exhaust steam extraction and supply unit for providing first intermediate exhaust steam extraction, a low-pressure cylinder output adjusting unit for reducing first low-pressure cylinder output, and a second intermediate exhaust steam extraction and supply unit for reducing second low-pressure cylinder output; the first backpressure power generation unit generates power and supplies heat based on first intermediate discharge steam extraction, and the first heat supply network heating unit secondarily heats heat supply network return water based on the first intermediate discharge steam extraction; the second intermediate exhaust steam extraction and supply unit provides second intermediate exhaust steam extraction, the exhaust steam flow adjusting unit adjusts the exhaust steam flow to enable the second combined heat and power generation unit to be switched to operate under different working conditions, the high-back-pressure heating unit preliminarily heats heat supply network return water, and the second back-pressure power generation unit generates power and supplies heat. And the second heat supply network heating unit secondarily heats the heat supply network return water. The method is realized based on the device. According to the scheme, the heat efficiency, the waste heat utilization rate, the energy utilization rate and the peak regulation flexibility of the cogeneration unit can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of thermoelectric decoupling, and in particular to a method for cascaded energy utilization by combining low-pressure cylinder micro-output with high back pressure transformation. Background Art

[0002] At present, cogeneration technology plays an indispensable role in ensuring heating for people's livelihood. It has become a top priority to promote the flexibility transformation of existing coal-fired power units, especially cogeneration units. Improving the flexibility of units through different thermal-electric decoupling technologies is a more effective technical approach.

[0003] In the existing technology, the thermal-electric decoupling technology mainly includes: configuring a hot water storage tank, configuring an electric boiler, removing the low-pressure cylinder, high back pressure modification, bypass heating, and waste heat heating. However, each of these thermal-electric decoupling technologies has certain disadvantages. Traditional cogeneration units use medium-pressure cylinder extraction steam for heating when extracting steam for heating. The loss of the low-pressure cylinder exhaust steam cold source cannot be fully utilized, and a large amount of medium-pressure exhaust steam is only used for heating. The high-grade heat is used at a reduced grade, and the energy utilization rate is also low. In addition, the peak-shaving flexibility of traditional cogeneration units is poor.

[0004] Therefore, how to improve the thermal efficiency, waste heat utilization, energy utilization and peak load flexibility of cogeneration units has become an issue to be resolved. Summary of the invention

[0005] The purpose of this application is to provide a method for energy cascade utilization by combining low-pressure cylinder micro-output with high back pressure transformation, which can solve the problems of low thermal efficiency, waste heat utilization rate and energy utilization rate and poor peak-shaving flexibility of cogeneration units in the prior art.

[0006] In a first aspect, an embodiment of the present application provides a cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation, the device comprising:

[0007] The first middle row steam extraction and steam supply unit, the low-pressure cylinder output regulating unit, the first low-pressure cylinder, the first back-pressure power generation unit, the first heat network heating unit, and the first exhaust steam pipeline provided between the fourth output end of the first middle row steam extraction and steam supply unit and the steam inlet of the first low-pressure cylinder of the first cogeneration unit, the second middle row steam extraction and steam supply unit, the exhaust steam flow regulating unit, the second low-pressure cylinder, the high back-pressure heating unit, the second back-pressure power generation unit, the second heat network heating unit, and the second exhaust steam pipeline provided between the third output end of the second middle row steam extraction and steam supply unit and the steam inlet of the second low-pressure cylinder of the second cogeneration unit;

[0008] The first output end of the first middle row steam extraction and steam supply unit is connected to the first input end of the first back pressure power generation unit, the second output end of the first middle row steam extraction and steam supply unit is connected to the second input end of the first heat network heating unit, the third output end of the first middle row steam extraction and steam supply unit is connected to the third input end of the first heat network heating unit, the fourth output end of the first middle row steam extraction and steam supply unit is connected to the first end of the low pressure cylinder output regulating unit, and the first middle row steam extraction and steam supply unit is used to provide the first middle row steam extraction to the first back pressure power generation unit and the first heat network heating unit;

[0009] The low-pressure cylinder output regulating unit is arranged on the first exhaust pipe, the second end of the low-pressure cylinder output regulating unit is connected to the steam inlet of the first low-pressure cylinder, the exhaust outlet of the first low-pressure cylinder is connected to the input end of the first air-cooling island, and the low-pressure cylinder output regulating unit is used to reduce the output of the first low-pressure cylinder;

[0010] The second input end of the first back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, the output end of the first back-pressure power generation unit is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit, and the first back-pressure power generation unit is used to generate electricity and heat based on the first intermediate exhaust steam extraction;

[0011] The output end of the first heating network heating unit outputs the heating network supply water, and the first heating network heating unit is used to secondary heat the heating network return water that has been preliminarily heated by the high back pressure heating unit based on the first intermediate exhaust steam extraction, and output the heated heating network return water;

[0012] The first output end of the second middle row extraction steam supply unit is connected to the first input end of the second back pressure power generation unit, the second output end of the second middle row extraction steam supply unit is connected to the second input end of the second heat network heating unit, the third output end of the second middle row extraction steam supply unit is connected to the first end of the exhaust steam flow regulating unit, and the second middle row extraction steam supply unit is used to provide the second middle row extraction steam to the second back pressure power generation unit and the second heat network heating unit;

[0013] The exhaust steam flow regulating unit is arranged on the second exhaust steam pipeline, the second end of the exhaust steam flow regulating unit is connected to the steam inlet of the second low-pressure cylinder, the first exhaust steam outlet of the second low-pressure cylinder is connected to the input end of the second air-cooling island, and the exhaust steam flow regulating unit is used to regulate the exhaust steam flow input to the second low-pressure cylinder, so that the second cogeneration unit can switch to operate under pure condensation, extraction condensation or back pressure conditions;

[0014] The first input end of the high back pressure heating unit is connected to the second exhaust steam outlet of the second low pressure cylinder, the second input end of the high back pressure heating unit inputs the return water of the heating network, the second output end of the high back pressure heating unit is connected to the input end of the exhaust steam device, and the high back pressure heating unit is used to preliminarily heat the return water of the heating network based on the exhaust steam of the second low pressure cylinder;

[0015] The second input end of the second back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, the output end of the second back-pressure power generation unit is connected to the first input end of the second heat network heating unit, and the second back-pressure power generation unit is used to generate electricity and heat based on the second middle exhaust steam extraction;

[0016] The output end of the second heating network heating unit outputs the heating network supply water. The second heating network heating unit is used to secondary heat the heating network return water heated by the high back pressure heating unit based on the second intermediate exhaust steam extraction, and output the heated heating network return water.

[0017] In a possible implementation manner of the first aspect, the first middle row extraction steam supply unit includes: a first intermediate pressure cylinder and a first middle row extraction steam control module;

[0018] The first end of the first middle row steam extraction control module is respectively connected to the exhaust outlet of the first medium-pressure cylinder and the first end of the low-pressure cylinder output regulating unit, the second end of the first middle row steam extraction control module is connected to the input end of the first back-pressure power generation unit, the third end of the first middle row steam extraction control module is connected to the second end input end of the first heat network heating unit, the fourth end of the first middle row steam extraction control module is connected to the third input end of the first heat network heating unit, and the first middle row steam extraction control module is used to control the first middle row steam extraction.

[0019] In a possible implementation of the first aspect, the low-pressure cylinder output regulating unit includes a double-valve plate heating butterfly valve; the double-valve plate heating butterfly valve is arranged on the first exhaust steam pipe, the first end of the double-valve plate heating butterfly valve is connected to the fourth output end of the first middle row steam extraction and supply unit, and the second end of the double-valve plate heating butterfly valve is connected to the steam inlet of the first low-pressure cylinder.

[0020] In a possible implementation manner of the first aspect, the first intermediate exhaust steam extraction control module includes: a first pneumatic check valve, a first hydraulic fast closing regulating valve, a first electric shut-off valve, a first steam supply gate valve, a first steam supply regulating valve, a first main steam supply pipeline arranged between the exhaust outlet of the first intermediate pressure cylinder and the second input end of the first heating network heating unit, a first bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the input end of the first back pressure power generation unit, and a second bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the third input end of the first heating network heating unit;

[0021] The first pneumatic check valve, the first hydraulic fast closing regulating valve and the first electric shut-off valve are sequentially arranged on the first main steam supply pipeline, the first steam supply gate valve is arranged on the first bypass steam supply pipeline, and the first steam supply regulating valve is arranged on the second bypass steam supply pipeline;

[0022] The first end of the first pneumatic check valve is connected to the first end of the low-pressure cylinder output regulating unit, the second end of the first pneumatic check valve is connected to the first end of the first hydraulic quick-closing regulating valve, the second end of the first hydraulic quick-closing regulating valve is connected to the first end of the first electric shut-off valve, the second end of the first electric shut-off valve, the first end of the first steam supply gate valve and the first end of the first steam supply regulating valve are respectively connected to the second input end of the first heating network heating unit, the second end of the first steam supply gate valve is connected to the input end of the first back pressure power generation unit, and the second end of the first steam supply regulating valve is connected to the third input end of the first heating network heating unit.

[0023] In a possible implementation manner of the first aspect, the first back-pressure power generation unit includes: a first back-pressure steam turbine, a first back-pressure generator, and a first back-pressure generator condenser;

[0024] The input end of the first back-pressure steam turbine is connected to the first output end of the first middle row steam extraction steam supply unit, the output end of the first back-pressure steam turbine is connected to the input end of the first back-pressure generator, and the first back-pressure steam turbine is used to generate mechanical energy based on the first middle row steam extraction; the output end of the first back-pressure generator is connected to the first input end of the first back-pressure generator condenser, and the first back-pressure generator is used to generate electricity based on the mechanical energy generated by the first back-pressure steam turbine;

[0025] The second input end of the first back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output end of the first back-pressure generator condenser is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit. The first back-pressure generator condenser is used for cooling the exhaust steam of the first back-pressure generator and recovering energy.

[0026] In a possible implementation manner of the first aspect, the first heating network heating unit includes: a first heating network circulating water pump small turbine and a first heating network heater;

[0027] The input end of the small steam turbine of the first heat network circulating water pump is connected to the third output end of the first middle row steam extraction and supply unit, and the output end of the small steam turbine of the first heat network circulating water pump is connected to the third input end of the first heat network heater, and the small steam turbine of the first heat network circulating water pump is used to drive the first heat network heater;

[0028] The first input end of the first heating network heater is connected to the output end of the first back pressure power generation unit, the second input end of the first heating network heater is connected to the second output end of the first middle row steam extraction supply unit, the output end of the first heating network heater outputs heating network supply water, and the first heating network heater is used to secondary heat the heating network return water heated by the high back pressure heating unit based on the first middle row steam extraction, and output the heated heating network return water.

[0029] In a possible implementation manner of the first aspect, the second middle row extraction steam supply unit includes: a second intermediate pressure cylinder and a second middle row extraction steam control module;

[0030] The first end of the second middle exhaust steam extraction control module is respectively connected to the exhaust outlet of the second intermediate pressure cylinder and the first end of the exhaust flow regulating unit, the second end of the second middle exhaust steam extraction control module is connected to the input end of the second back pressure power generation unit, the third end of the second middle exhaust steam extraction control module is connected to the second end input end of the second heat network heating unit, and the second middle exhaust steam extraction control module is used to control the second middle exhaust steam extraction.

[0031] In a possible implementation manner of the first aspect, the second intermediate exhaust steam extraction control module includes: a second pneumatic check valve, a second hydraulic fast closing regulating valve, a second electric shut-off valve, a second steam supply gate valve, a second steam supply regulating valve, a second main steam supply pipeline arranged between the exhaust outlet of the second intermediate pressure cylinder and the second input end of the second heating network heating unit, and a third bypass steam supply pipeline arranged between the second end of the second electric shut-off valve and the input end of the second back pressure power generation unit;

[0032] The second pneumatic check valve, the second hydraulic quick-closing regulating valve, the second electric shut-off valve and the second steam supply regulating valve are sequentially arranged on the second main steam supply pipeline, and the second steam supply gate valve is arranged on the third bypass steam supply pipeline; the second end of the second pneumatic check valve is connected to the first end of the second hydraulic quick-closing regulating valve, the second end of the second hydraulic quick-closing regulating valve is connected to the first end of the second electric shut-off valve, the second end of the second electric shut-off valve and the first end of the second steam supply gate valve are respectively connected to the first end of the second steam supply regulating valve, the second end of the second steam supply gate valve is connected to the input end of the second back pressure power generation unit, and the second end of the second steam supply regulating valve is connected to the second input end of the second heating network heating unit.

[0033] In a possible implementation of the first aspect, the exhaust steam flow regulating unit includes a connecting pipe hydraulic butterfly valve; the connecting pipe hydraulic butterfly valve is arranged on the second exhaust steam pipe, the first end of the connecting pipe hydraulic butterfly valve is connected to the third output end of the second middle exhaust steam extraction and supply unit, and the second end of the connecting pipe hydraulic butterfly valve is connected to the steam inlet of the second low-pressure cylinder.

[0034] In a possible implementation of the first aspect, the high back pressure heating unit includes a high back pressure condenser; a first input end of the high back pressure condenser is connected to the second exhaust outlet of the second low pressure cylinder, a second input end of the high back pressure condenser inputs heat network return water, a first output end of the high back pressure condenser is respectively connected to the second input end of the first back pressure power generation unit and the second input end of the second back pressure power generation unit through a heat network circulating water pipeline, and a second output end of the high back pressure condenser is connected to the input end of the exhaust device.

[0035] In a possible implementation manner of the first aspect, the second back-pressure power generation unit includes: a second back-pressure steam turbine, a second back-pressure generator, and a second back-pressure generator condenser;

[0036] The input end of the second back-pressure steam turbine is connected to the first output end of the second middle row steam extraction steam supply unit, the output end of the second back-pressure steam turbine is connected to the input end of the second back-pressure generator, and the second back-pressure steam turbine is used to generate mechanical energy based on the second middle row steam extraction; the output end of the second back-pressure generator is connected to the first input end of the second back-pressure generator condenser, and the second back-pressure generator is used to generate electricity based on the mechanical energy generated by the second back-pressure steam turbine;

[0037] The second input end of the second back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output ends of the second back-pressure generator condenser are respectively connected to the output end of the first back-pressure power generation unit and the first input end of the second heat network heating unit. The second back-pressure generator condenser is used for cooling the exhaust steam of the second back-pressure generator and recovering energy.

[0038] In a possible implementation manner of the first aspect, the second heating network heating unit includes: a second heating network circulating water pump small turbine and a second heating network heater;

[0039] The input end of the small steam turbine of the second heat network circulating water pump is connected to the second output end of the second middle row steam extraction and supply unit, and the output end of the small steam turbine of the second heat network circulating water pump is connected to the second input end of the second heat network heater. The small steam turbine of the second heat network circulating water pump is used to drive the second heat network heater.

[0040] The first input end of the second heating network heater is connected to the output end of the first back pressure power generation unit, and the output end of the second heating network heater outputs the heating network supply water. The second heating network heater is used to reheat the heating network return water heated by the high back pressure heating unit and output the heated heating network return water.

[0041] In a possible implementation manner of the first aspect, the device further includes a heat network circulating water driving unit;

[0042] The input end of the heating network circulating water driving unit is connected to the output end of the first back-pressure power generation unit and the output end of the second back-pressure power generation unit through the heating network circulating water pipeline, the first output end of the heating network circulating water driving unit is connected to the first input end of the first heating network heating unit through the heating network circulating water pipeline, the second output end of the heating network circulating water driving unit is connected to the first input end of the second heating network heating unit through the heating network circulating water pipeline, and the heating network circulating water driving unit is used to provide power for the heating network return water circulation.

[0043] In a possible implementation manner of the first aspect, the heating network circulating water driving unit includes a heating network circulating water pump;

[0044] The input end of the heating network circulating water pump is connected to the output end of the first back-pressure power generation unit and the output end of the second back-pressure power generation unit through the heating network circulating water pipeline, the first output end of the heating network circulating water pump is connected to the first input end of the first heating network heating unit through the heating network circulating water pipeline, and the second output end of the heating network circulating water pump is connected to the first input end of the second heating network heating unit through the heating network circulating water pipeline.

[0045] In a second aspect, an embodiment of the present application provides a cogeneration system of low-pressure cylinder micro-output combined with high back pressure transformation, the system comprising: a first air-cooling island, a second air-cooling island, a heat network return water supply device, an exhaust device, a first heat network water supply device, a second heat network water supply device, and a cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to any one of the first aspects;

[0046] The first input end of the cogeneration device is connected to the output end of the heat network return water supply device, and the first output end of the cogeneration device is connected to the input end of the first air cooling island, and the first air cooling island is used to reduce the exhaust steam temperature of the first low-pressure cylinder so that the exhaust steam of the first low-pressure cylinder is condensed into water; the second output end of the cogeneration device is connected to the input end of the second air cooling island, and the second air cooling island is used to reduce the exhaust steam temperature of the second low-pressure cylinder so that the exhaust steam of the second low-pressure cylinder is condensed into water;

[0047] The third output end of the cogeneration device is connected to the input end of the exhaust device, which is used to exhaust the exhaust steam of the high back pressure heating unit; the fourth output end of the cogeneration device is connected to the input end of the first heat network water supply device, which is used to provide heat network water supply to users; the fifth output end of the cogeneration device is connected to the input end of the second heat network water supply device, which is used to provide heat network water supply to users, and the cogeneration device is used to generate electricity and supply heat to users.

[0048] In a third aspect, an embodiment of the present application provides an energy cascade utilization method of a low-pressure cylinder micro-output combined with a high back pressure transformation, which is implemented based on a cogeneration device of a low-pressure cylinder micro-output combined with a high back pressure transformation in any one of the first aspects, and the method includes:

[0049] Based on the first middle exhaust steam supply unit of the first cogeneration unit, the first middle exhaust steam is provided to the first back pressure power generation unit and the first heat network heating unit; based on the low pressure cylinder output regulating unit, the output of the first low pressure cylinder is reduced, and the heat generated by the blast of the first low pressure cylinder is cooled;

[0050] Based on the first back pressure power generation unit, the first middle exhaust steam extraction is used to generate electricity and supply heat; based on the first heat network heating unit, the first middle exhaust steam extraction is used to secondary heat the heat network return water that has been preliminarily heated by the high back pressure heating unit, and the heated heat network return water is output;

[0051] Based on the second middle exhaust steam supply unit of the second cogeneration unit, the second middle exhaust steam is provided to the second back pressure power generation unit and the second heat network heating unit; based on the exhaust steam flow regulating unit, the exhaust steam flow input to the second low pressure cylinder is adjusted, so that the second cogeneration unit can switch to operate under pure condensation, extraction condensation or back pressure conditions;

[0052] Based on the high back pressure heating unit, the exhaust steam of the second low pressure cylinder is used to preliminarily heat the return water of the heat network; based on the second back pressure power generation unit, the second middle exhaust steam is used to generate electricity and supply heat; based on the second heat network heating unit, the second middle exhaust steam is used to secondary heat the return water of the heat network heated by the high back pressure heating unit, and the heated return water of the heat network is output;

[0053] Wherein, the first middle row steam extraction and supply unit and the first low-pressure cylinder are arranged at the first stage of the first cogeneration unit, the first back pressure power generation unit is arranged at the second stage of the first cogeneration unit, and the first heat network heating unit is arranged at the third stage of the first cogeneration unit;

[0054] The second middle row extraction steam supply unit, the second low-pressure cylinder and the high back-pressure heating unit are arranged at the first stage of the second cogeneration unit, the second back-pressure power generation unit is arranged at the second stage of the second cogeneration unit, and the second heat network heating unit is arranged at the third stage of the second cogeneration unit.

[0055] In a possible implementation manner of the third aspect, the first intermediate row steam extraction and steam supply unit includes a first intermediate pressure cylinder, the low pressure cylinder output regulating unit includes a double valve plate heating butterfly valve, the double valve plate heating butterfly valve includes: a main valve plate and a small valve plate; based on the low pressure cylinder output regulating unit, the output of the first low pressure cylinder is reduced, and the heat generated by the first low pressure cylinder blast is cooled, including:

[0056] Close the main valve plate and adjust the opening of the small valve plate to a preset opening so that the exhaust steam of the first intermediate pressure cylinder corresponding to the exhaust flow rate of the preset opening enters the first low pressure cylinder to reduce the output of the first low pressure cylinder and cool the heat generated by the blowing of the first low pressure cylinder.

[0057] In a possible implementation manner of the third aspect, providing first middle exhaust steam extraction to the first back pressure power generation unit and the first heat network heating unit based on the first middle exhaust steam extraction supply unit of the first cogeneration unit includes:

[0058] A first intermediate exhaust steam extraction supply unit is provided to provide a first back pressure power generation unit and a first heat network heating unit with a remaining exhaust steam flow; wherein the remaining exhaust steam flow is the difference between the total exhaust steam flow of the first intermediate pressure cylinder and the exhaust steam flow corresponding to the preset opening.

[0059] In a possible implementation manner of the third aspect, the second intermediate exhaust steam supply unit includes a second intermediate pressure cylinder; based on the exhaust steam flow regulating unit, the exhaust steam flow input to the second low-pressure cylinder is adjusted so that the second cogeneration unit switches to operate under pure condensation, extraction condensation or back pressure conditions, including:

[0060] Based on the exhaust steam flow rate regulating unit, the exhaust steam flow rate of the second intermediate pressure cylinder input into the second low pressure cylinder is adjusted to a first preset exhaust steam flow rate, so that the second cogeneration unit operates under a pure condensing condition;

[0061] or adjusting the exhaust steam flow rate of the second intermediate pressure cylinder input into the second low pressure cylinder to a second preset exhaust steam flow rate based on the exhaust steam flow rate regulating unit, so that the second cogeneration unit operates under the extraction and condensation condition;

[0062] Alternatively, based on the exhaust steam flow rate regulating unit, the exhaust steam flow rate of the second intermediate pressure cylinder input into the second low pressure cylinder is regulated to a third preset exhaust steam flow rate, so that the second cogeneration unit operates under a back pressure condition.

[0063] In a possible implementation manner of the third aspect, providing second middle exhaust steam extraction to the second back pressure power generation unit and the second heat network heating unit based on the second middle exhaust steam extraction supply unit of the second cogeneration unit includes:

[0064] Based on the second middle row extraction steam supply unit, a second middle row extraction steam with a first residual exhaust steam flow rate is provided to the second back pressure power generation unit and the second heat network heating unit; wherein the first residual exhaust steam flow rate is the difference between the total exhaust steam flow rate of the second middle row extraction steam and the first preset exhaust steam flow rate;

[0065] Or based on the second middle row extraction steam supply unit, a second middle row extraction steam with a second residual exhaust steam flow is provided to the second back pressure power generation unit and the second heat network heating unit; wherein the second residual exhaust steam flow is the difference between the total exhaust steam flow of the second middle row extraction steam and the second preset exhaust steam flow;

[0066] Or based on the second middle row extraction steam supply unit, a second middle row extraction steam with a third residual exhaust steam flow is provided to the second back pressure power generation unit and the second heat network heating unit; wherein the third residual exhaust steam flow is the difference between the total exhaust steam flow of the second middle row extraction steam and the third preset exhaust steam flow.

[0067] In a possible implementation manner of the third aspect, the cogeneration device further includes a heat network circulating water drive unit, and the heat network circulating water drive unit includes a heat network circulating water pump; and the method further includes:

[0068] The heat network circulating water pump provides power for the heat network return water circulation.

[0069] In a possible implementation manner of the third aspect, the first middle row steam extraction and steam supply unit includes a first middle row steam extraction control module, the first middle row steam extraction control module includes a first steam supply regulating valve, and the first heating network heating unit includes a first heating network circulating water pump small turbine; the second middle row steam extraction and steam supply unit includes a second middle row steam extraction control module, the second middle row steam extraction control module includes a second steam supply regulating valve, and the second heating network heating unit includes a second heating network circulating water pump small turbine; before providing power to the heating network return water circulation based on the heating network circulating water pump, the method also includes:

[0070] The first steam source amount of the first middle row extraction steam is calculated according to the input power of the heating network circulating water pump, and the second steam supply regulating valve is closed to prevent the second middle row extraction steam from entering the second heating network circulating water pump small steam turbine. At the same time, the first steam supply regulating valve is adjusted to allow the first middle row extraction steam of the first steam source amount to enter the first heating network circulating water pump small steam turbine; the first middle row extraction steam is used to generate the first mechanical energy based on the first heating network circulating water pump small steam turbine, and the first mechanical energy is used to drive the heating network circulating water pump based on the first heating network circulating water pump small steam turbine.

[0071] In a possible implementation manner of the third aspect, before providing power to the heat network return water circulation based on the heat network circulation water pump, the method further includes:

[0072] The second steam source amount of the second middle row extraction steam is calculated according to the input power of the heating network circulating water pump, and the first steam supply regulating valve is closed to prevent the first middle row extraction steam from entering the first heating network circulating water pump small steam turbine, and the second steam supply regulating valve is adjusted at the same time to allow the second middle row extraction steam of the second steam source amount to enter the second heating network circulating water pump small steam turbine; the second middle row extraction steam is used to generate second mechanical energy based on the second heating network circulating water pump small steam turbine, and the second mechanical energy is used to drive the heating network circulating water pump based on the second heating network circulating water pump small steam turbine.

[0073] In a possible implementation manner of the third aspect, before providing power to the heat network return water circulation based on the heat network circulation water pump, the method further includes:

[0074] According to the input power of the heat network circulating water pump, the first steam source quantity of the first middle row extraction steam and the second steam source quantity of the second middle row extraction steam are calculated respectively, and the first steam supply regulating valve is adjusted so that the first middle row extraction steam of the first steam source quantity enters the small steam turbine of the first heat network circulating water pump, and the second steam supply regulating valve is adjusted so that the second middle row extraction steam of the second steam source quantity enters the small steam turbine of the second heat network circulating water pump;

[0075] The first heat network circulating water pump small steam turbine utilizes the first middle exhaust steam to generate the first mechanical energy, and the second heat network circulating water pump small steam turbine utilizes the second middle exhaust steam to generate the second mechanical energy;

[0076] The first mechanical energy is utilized based on the small steam turbine of the first heat network circulating water pump, and the second mechanical energy is utilized based on the small steam turbine of the second heat network circulating water pump to drive the heat network circulating water pump.

[0077] In the cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation of the present application, the first middle row steam extraction supply unit is used to provide the first middle row steam extraction, the low-pressure cylinder output adjustment unit is used to reduce the output of the first low-pressure cylinder, the first back pressure power generation unit is used to generate electricity and heat based on the first middle row steam extraction, reducing the use of high-grade heat for downgraded use, and the first heat network heating unit is used to heat the heat network return water after preliminary heating based on the first middle row steam extraction. The second middle row steam extraction supply unit is used to provide the second middle row steam extraction, the exhaust steam flow adjustment unit is used to switch the second cogeneration unit to operate under different working conditions by adjusting the exhaust steam flow, which can respond to the peak-shaving demand of the system in different heating periods and improve the peak-shaving flexibility, the high back pressure heating unit is used to realize low-grade waste heat heating based on preliminary heating of the heat network return water, the second back pressure power generation unit is used to generate electricity and heat based on the second middle row steam extraction, reducing the use of high-grade heat for downgraded use, and the second heat network heating unit is used to secondary heat the heat network return water heated by the high back pressure heating unit.

[0078] The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation of the present application sets three steps in the two cogeneration units respectively, provides the first middle row extraction steam through the first middle row extraction steam supply unit, the low-pressure cylinder output regulating unit reduces the output of the first low-pressure cylinder, the first back-pressure power generation unit uses the first middle row extraction steam to generate electricity and supply heat, the first hot network heating unit uses the first middle row extraction steam to secondary heat the hot network return water after preliminary heating, the second middle row extraction steam supply unit provides the second middle row extraction steam, the exhaust steam flow regulating unit switches the second cogeneration unit to operate under different working conditions by adjusting the exhaust steam flow, the high back-pressure heating unit uses the exhaust steam of the second low-pressure cylinder to preliminarily heat the hot network return water, the second back-pressure power generation unit uses the second middle row extraction steam to generate electricity and supply heat, and the second hot network heating unit secondary heats the hot network return water heated by the high back-pressure heating unit, thereby realizing the cascade utilization of thermal energy of the middle row extraction steam.

[0079] The solution of the present application can improve the thermal efficiency, waste heat utilization rate, energy utilization rate and peak-shaving flexibility of the cogeneration unit while responding to the peak-shaving demand of the system during different heating periods. In addition, the high back-pressure unit cascade heating is realized, and a stronger heating capacity is obtained at the expense of part of the output power. In order to realize the hierarchical utilization of the middle exhaust steam extraction, a steam pipeline is drawn from the middle exhaust steam extraction mother pipe of each of the two cogeneration units. The middle exhaust steam in the two steam pipelines is used as the steam source of the two back-pressure steam turbines, which are backed up for each other, and have strong ease of use and practicality.

[0080] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0082] Figure 1 It is a schematic block diagram of the overall structure of a heat and power cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation provided in an embodiment of the present application;

[0083] Figure 2 It is a schematic block diagram of the specific structure of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application;

[0084] Figure 3 It is a schematic block diagram of a heat and power cogeneration system 200 of low-pressure cylinder micro-output combined with high back pressure transformation provided in an embodiment of the present application;

[0085] Figure 4 It is a schematic diagram of the steps of the energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application. DETAILED DESCRIPTION

[0086] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0087] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0088] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0089] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0090] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0091] In addition, in the description of the present application, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0092] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0093] In the present application specification, unless otherwise specified, directional words such as "up, down, left, right" generally refer to the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the invented product is usually placed when in use.

[0094] In the present application specification, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0095] In recent years, with the acceleration of my country's energy transformation and the implementation of the "dual carbon" goals, China's new energy has developed rapidly. However, this has also brought unprecedented challenges to the safety and stability of the power system, especially in new energy resource-rich areas such as western and northern China, where the contradiction between the huge total amount of clean energy resources and insufficient existing regulation capacity is particularly prominent. my country urgently needs to promote the construction of new coal-fired power units around enhancing the flexibility and dynamic adaptability of the power system and solve the problem of power consumption. Among them, the flexibility of the power system generally refers to the ability of the power system to economically call on various flexible resources to cope with the uncertainty of power sources, power grids and loads in order to maintain a dynamic balance between power supply and demand.

[0096] At present, cogeneration technology plays an indispensable role in ensuring heating for people's livelihood. It is of utmost importance to promote the flexibility transformation of existing coal-fired power units, especially cogeneration units. Improving the flexibility of units by using different thermal-electric decoupling technologies is a relatively effective technical approach. Cogeneration is a multi-generation energy system that integrates heating and power generation processes to achieve efficient energy utilization, which can greatly improve energy utilization.

[0097] The essence of thermal-electric decoupling is to replace steam turbine heating with other heat sources, reduce the heating power of steam turbine, and then reduce the power generation power based on heat. By adding hot water storage tanks, electric boilers and other equipment (storing heat energy or directly converting electrical energy into heat energy) or modifying the steam transmission process, the unit can meet the heat load demand and participate in the deep peak regulation of the power grid, thereby effectively improving the operating flexibility of the cogeneration unit.

[0098] In the existing technology, the thermal-electric decoupling technology mainly includes: configuring hot water storage tanks for heating, configuring electric boilers for heating, cutting off low-pressure cylinders for heating (low-pressure cylinders for zero-output heating), high back pressure transformation for heating, high and medium pressure cylinders for bypass heating, and circulating water waste heat recovery for heating, etc. Configuring hot water storage tanks for heating is to set up a heat storage tank system on the heating network side for heating, which weakens the time coupling degree of heat-electric load; configuring electric boilers for heating converts electrical energy into thermal energy by electric heating; cutting off low-pressure cylinders for heating is to cut off all steam inlet of low-pressure cylinders, making the low-pressure cylinders "zero output" and operating in a back pressure heating mode under vacuum conditions; high back pressure transformation for heating is to increase the back pressure to increase the circulating water temperature for heating; high and medium pressure cylinders for bypass heating is to use the bypass steam supply pipeline of the high and medium pressure cylinders to reduce the temperature and pressure of part of the high-quality steam for heating; circulating water waste heat recovery for heating is to use an absorption heat pump to extract part of the steam to drive the heat pump to recover the circulating water waste heat, thereby enhancing the heating capacity of the unit.

[0099] A large number of studies on the flexibility transformation of thermal decoupling of cogeneration units have focused on the transformation characteristics and transformation effects of a single technology, and there are fewer studies on combining multiple technologies to meet the heating needs of cogeneration units. The general thermal decoupling technologies also have certain disadvantages: the hot water storage tank occupies a large area and has a weak adaptability to the long-term low-load peak-shaving of the system; the investment in electric boilers is high, the energy utilization efficiency is low, and the applicability is poor; the removal of the low-pressure cylinder has the risk of blade dynamic stress, blasting, and water erosion that affect the safe operation of the unit, and cannot meet the peak-shaving needs of continuously tracking the fluctuating power generation load; the flexibility transformation of the high back pressure transformation is not thorough enough; there is throttling loss in the bypass heating of the high and medium pressure cylinders; the flexibility of circulating water waste heat recovery is poor.

[0100] Traditional cogeneration units use medium-pressure cylinder extraction steam for heating, and the loss of low-pressure cylinder exhaust cold source cannot be fully utilized. In addition, a large amount of medium-exhaust steam (exhaust steam from the medium-pressure cylinder of the turbine) is only used for heating, and high-quality heat is used at a lower quality, resulting in low energy utilization. In addition, the peak-shaving flexibility of traditional cogeneration units is poor. Therefore, conducting research on new coupling technologies has great potential and is of great significance for adapting to the flexibility transformation of cogeneration units.

[0101] From the above, it can be seen that how to improve the thermal efficiency, waste heat utilization rate, energy utilization rate and peak load flexibility of cogeneration units has become a problem to be solved.

[0102] In response to the above-mentioned defects, an embodiment of the present application provides a cogeneration device with low-pressure cylinder micro-output combined with high back pressure modification, wherein the first middle row extraction steam supply unit is used to provide the first middle row extraction steam, the low-pressure cylinder output regulating unit is used to reduce the output of the first low-pressure cylinder, the first back-pressure power generation unit is used to generate electricity and heat based on the first middle row extraction steam, thereby reducing the use of high-grade heat for downgrading, and the first heat network heating unit is used to heat the heat network return water after preliminary heating based on the secondary heating of the first middle row extraction steam.

[0103] The second middle row extraction steam supply unit is used to provide the second middle row extraction steam, the exhaust steam flow regulating unit is used to switch the second cogeneration unit under different operating conditions by adjusting the exhaust steam flow, which can respond to the peak-shaving needs of the system in different heating periods and improve the peak-shaving flexibility. The high back pressure heating unit is used to achieve low-grade waste heat heating based on the preliminary heating of the heat network return water. The second back pressure power generation unit is used for power generation and heating based on the second middle row extraction steam, reducing the high-grade heat being used for downgrading. The second heat network heating unit is used for secondary heating of the heat network return water after being heated by the high back pressure heating unit.

[0104] The solution of this application realizes energy cascade utilization and makes full use of the waste heat of the cogeneration unit by coupling different thermoelectric decoupling technologies, namely the coupling of low-pressure cylinder micro-output and high back pressure transformation, and on this basis, designs energy cascade utilization and heating transformation of the cogeneration unit. While responding to the peak-shaving needs of the unit in different heating periods, it can improve the thermal efficiency, regulation efficiency, waste heat utilization rate, energy utilization rate and safety of the thermoelectric regulation of the cogeneration unit, so that the cogeneration unit can have higher flexibility, which is of great significance and engineering application value for the thermoelectric decoupling flexibility transformation of the cogeneration unit in the thermal power field, and has strong ease of use and practicality.

[0105] The overall structure of the cogeneration device with low-pressure cylinder micro-output and high back pressure transformation provided in the embodiment of the present application is introduced below through specific embodiments.

[0106] See also Figure 1 , Figure 1 1 is a schematic block diagram of the overall structure of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application. Figure 1 As shown, the cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation includes: a first middle row steam extraction and supply unit 111 of the first cogeneration unit Z1, a low-pressure cylinder output regulating unit 112, the first low-pressure cylinder 2, a first back-pressure power generation unit 113, a first heat network heating unit 114, and a first exhaust steam pipeline arranged between the fourth output end (fourth exhaust steam outlet) of the first middle row steam extraction and supply unit 111 and the steam inlet of the first low-pressure cylinder 2, a second middle row steam extraction and supply unit 115 of the second cogeneration unit Z2, an exhaust steam flow regulating unit 116, the second low-pressure cylinder 10, a high back-pressure heating unit 117, a second back-pressure power generation unit 118, a second heat network heating unit 119, and a second exhaust steam pipeline arranged between the third output end of the second middle row steam extraction and supply unit 115 and the steam inlet of the second low-pressure cylinder 10.

[0107] Among them, the first cogeneration unit Z1 is used for the micro-output transformation of the first low-pressure cylinder 2, and the second cogeneration unit Z2 is used for high back pressure transformation.

[0108] In one embodiment, the first output end (first exhaust steam outlet) of the first middle row steam extraction and steam supply unit 111 is connected to the first input end of the first back pressure power generation unit 113, the second output end (second exhaust steam outlet) of the first middle row steam extraction and steam supply unit 111 is connected to the second input end of the first heat network heating unit 114, the third output end (third exhaust steam outlet) of the first middle row steam extraction and steam supply unit 111 is connected to the third input end of the first heat network heating unit 114, and the fourth output end of the first middle row steam extraction and steam supply unit 111 is connected to the first end of the low pressure cylinder output regulating unit 112. The first middle row steam extraction and steam supply unit 111 is used to provide the first middle row steam extraction to the first back pressure power generation unit 113 and the first heat network heating unit 114.

[0109] In one embodiment, the low-pressure cylinder output regulating unit 112 is disposed on the first exhaust pipe, the second end of the low-pressure cylinder output regulating unit 112 is connected to the steam inlet of the first low-pressure cylinder 2, the exhaust outlet of the first low-pressure cylinder 2 is connected to the input end of the first air-cooling island 210, and the first low-pressure cylinder 2 exhausts steam to the first air-cooling island 210. The first air-cooling island 210 is used to reduce the exhaust temperature of the first low-pressure cylinder 2 through an air cooling system so that the exhaust steam of the first low-pressure cylinder 2 is condensed into water for recycling. The low-pressure cylinder output regulating unit 112 is used to reduce the output of the first low-pressure cylinder 2 and adjust it to micro-output, that is, the output is very small and less than the preset output threshold.

[0110] Among them, the preset output threshold can be determined according to the specific situation in the actual application scenario, and is not specifically limited here. The output of the first low-pressure cylinder 2 is adjusted by adjusting the flow rate and pressure of the exhaust steam of the first middle row steam extraction and steam supply unit 111. At the same time, the low-pressure cylinder output adjustment unit 112 can also prevent the exhaust steam of the first middle row steam extraction and steam supply unit 111 from flowing in reverse, and change the flow direction of the exhaust steam of the first middle row steam extraction and steam supply unit 111.

[0111] In one embodiment, the second input end of the first back pressure power generation unit 113 is connected to the first output end of the high back pressure heating unit 117, and the output end of the first back pressure power generation unit 113 is respectively connected to the output end of the second back pressure power generation unit 118 and the first input end of the first heat network heating unit 114, and the first back pressure power generation unit 113 is used to generate electricity and heat based on the first middle exhaust steam extraction. A large amount of middle exhaust steam extraction of traditional cogeneration units is only used for heating, while the first middle exhaust steam extraction of this embodiment can be used for both heating and power supply, thereby reducing the use of high-grade heat for downgrading.

[0112] In one embodiment, the output end of the first heating network heating unit 114 outputs heating network water supply. The first heating network heating unit 114 is used to reheat the heating network return water that has been preliminarily heated by the high back pressure heating unit 117 based on the first intermediate exhaust steam extraction, and output the heated heating network return water. The heated heating network return water is used to provide heating to users.

[0113] In one embodiment, the first output end of the second middle row extraction steam supply unit 115 is connected to the first input end of the second back pressure power generation unit 118, the second output end of the second middle row extraction steam supply unit 115 is connected to the second input end of the second heat network heating unit 119, and the third output end of the second middle row extraction steam supply unit 115 is connected to the first end of the exhaust steam flow regulating unit 116. The second middle row extraction steam supply unit 115 is used to provide the second middle row extraction steam to the second back pressure power generation unit 118 and the second heat network heating unit 119.

[0114] In one embodiment, the exhaust steam flow regulating unit 116 is disposed on the second exhaust steam pipeline, the second end of the exhaust steam flow regulating unit 116 is connected to the steam inlet of the second low-pressure cylinder 10, and the first exhaust steam outlet of the second low-pressure cylinder 10 is connected to the input end of the second air-cooling island 220. The second air-cooling island 220 is used to reduce the exhaust steam temperature of the second low-pressure cylinder 10 through an air cooling system so that the exhaust steam of the second low-pressure cylinder 10 condenses into water for recycling. The exhaust steam flow regulating unit 116 is used to regulate the exhaust steam flow input to the second low-pressure cylinder 10 so that the second cogeneration unit Z2 switches to operate under pure condensation, extraction condensation or back pressure conditions. The exhaust steam flow regulating unit 116 is also used to adjust the exhaust steam pressure, prevent reverse flow, convert the exhaust steam flow direction and protect the pipeline system.

[0115] Among them, under pure condensing conditions, all steam is used for power generation; the extraction condensing condition combines the functions of pure condensing and heating, so that part of the steam is used for power generation and the other part is used for heating or other purposes; under back pressure conditions, all the exhaust steam of the turbine is supplied to other turbines or users.

[0116] In one embodiment, the first input end (heat release side inlet) of the high back pressure heating unit 117 is connected to the second exhaust outlet of the second low pressure cylinder 10, and the second input end (heat absorption side inlet) of the high back pressure heating unit 117 is input with the return water of the heat network. The second output end of the high back pressure heating unit 117 is connected to the input end of the exhaust device 240, and the high back pressure heating unit 117 exhausts steam to the exhaust device 240. The high back pressure heating unit 117 is used to preliminarily heat the return water of the heat network based on the exhaust steam of the second low pressure cylinder 10 to realize low-grade waste heat heating. The high back pressure heating unit 117 can heat the return water of the heat network from 30-40°C to about 70.5°C.

[0117] The high back pressure heating unit 117 can increase the back pressure of the second low pressure cylinder 10 to increase the temperature of the return water of the heating network.

[0118] In one embodiment, the second input end of the second back pressure power generation unit 118 is connected to the first output end of the high back pressure heating unit 117, and the output end of the second back pressure power generation unit 118 is connected to the first input end of the second heat network heating unit 119, and the second back pressure power generation unit 118 is used to generate electricity and heat based on the second middle exhaust steam extraction. A large amount of middle exhaust steam extraction of traditional cogeneration units is only used for heating, while the second middle exhaust steam extraction of this embodiment can be used for both heating and power supply, thereby reducing the use of high-grade heat for downgrading.

[0119] In one embodiment, the output end of the second heating network heating unit 119 outputs heating network water supply. The second heating network heating unit 119 is used to reheat the heating network return water heated by the high back pressure heating unit 117 based on the second intermediate exhaust steam extraction, and output the heated heating network return water. The heated heating network return water is used to provide heating to users.

[0120] This embodiment realizes energy cascade utilization and makes full use of the waste heat of the cogeneration unit by coupling different thermoelectric decoupling technologies, namely the coupling of low-pressure cylinder micro-output and high back pressure transformation, and on this basis, designs energy cascade utilization and heating transformation of the cogeneration unit. While responding to the peak-shaving demand of the unit in different heating periods, it can improve the thermal efficiency, regulation efficiency, waste heat utilization rate, energy utilization rate and safety of the thermoelectric regulation of the cogeneration unit, so that the cogeneration unit can have higher flexibility, which is of great significance and engineering application value for the thermoelectric decoupling flexibility transformation of the cogeneration unit in the thermal power field, and has strong ease of use and practicality.

[0121] The specific structure of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application is introduced below through a specific embodiment.

[0122] See also Figure 2 , Figure 2 1 is a schematic block diagram of the specific structure of the cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application. Figure 2 As shown, the first middle row steam extraction and supply unit 111 includes: a first intermediate pressure cylinder 1 and a first middle row steam extraction control module (valve group) 1112 .

[0123] In one embodiment, the first end of the first middle row steam extraction control module 1112 is respectively connected to the exhaust outlet of the first intermediate pressure cylinder 1 and the first end of the low pressure cylinder output regulating unit 112, the second end of the first middle row steam extraction control module 1112 is connected to the input end of the first back pressure power generation unit 113, the third end of the first middle row steam extraction control module 1112 is connected to the second end input end of the first heat network heating unit 114, the fourth end of the first middle row steam extraction control module 1112 is connected to the third input end of the first heat network heating unit 114, and the first middle row steam extraction control module 1112 is used to control the first middle row steam extraction.

[0124] The first intermediate pressure cylinder 1 is used to further expand the low-temperature, low-pressure steam in the high-pressure cylinder to increase the specific volume and temperature of the steam. The first low-pressure cylinder 2 is used to further expand the low-temperature, low-pressure steam in the first intermediate pressure cylinder 1 to further increase the specific volume of the steam, thereby improving the overall efficiency of the steam turbine.

[0125] In one embodiment, the low-pressure cylinder output regulating unit 112 includes a double-valve plate heating butterfly valve 3. The double-valve plate heating butterfly valve 3 is arranged on the first exhaust steam pipeline, the first end of the double-valve plate heating butterfly valve 3 is connected to the fourth output end of the first middle row extraction steam supply unit 111, and the second end of the double-valve plate heating butterfly valve 3 is connected to the steam inlet of the first low-pressure cylinder 2.

[0126] It should be noted that, in the present embodiment, no major changes are made to the main body of the first low-pressure cylinder 2. Instead, the steam inlet butterfly valve form of the first low-pressure cylinder 2 is optimized to achieve the first low-pressure cylinder 2 maintaining a relatively low steam inlet flow rate and maintaining a relatively low back pressure operation, making maximum use of the first middle row steam extraction for heating, and having a relatively strong low-load peak-shaving capability.

[0127] In one embodiment, the first intermediate exhaust steam extraction control module 1112 includes: a first pneumatic check valve 19, a first hydraulic quick-closing regulating valve 20, a first electric shut-off valve 21, a first steam supply gate valve 22, a first steam supply regulating valve 23, a first main steam supply pipeline arranged between the exhaust outlet of the first intermediate pressure cylinder 1 and the second input end of the first heating network heating unit 114, a first bypass steam supply pipeline arranged between the second end of the first electric shut-off valve 21 and the input end of the first back pressure power generation unit 113, and a second bypass steam supply pipeline arranged between the second end of the first electric shut-off valve 21 and the third input end of the first heating network heating unit 114.

[0128] In one embodiment, the first pneumatic check valve 19, the first hydraulic quick-closing regulating valve 20 and the first electric shut-off valve 21 are sequentially arranged on the first main steam supply pipeline, the first steam supply gate valve 22 is arranged on the first bypass steam supply pipeline, and the first steam supply regulating valve 23 is arranged on the second bypass steam supply pipeline.

[0129] In one embodiment, the first end of the first pneumatic check valve 19 is connected to the first end of the low-pressure cylinder output regulating unit 112, the second end of the first pneumatic check valve 19 is connected to the first end of the first hydraulic fast-closing regulating valve 20, the second end of the first hydraulic fast-closing regulating valve 20 is connected to the first end of the first electric shut-off valve 21, the second end of the first electric shut-off valve 21, the first end of the first steam supply gate valve 22, and the first end of the first steam supply regulating valve 23 are respectively connected to the second input end of the first heating network heating unit 114. The second end of the first steam supply gate valve 22 is connected to the input end of the first back pressure power generation unit 113, and the second end of the first steam supply regulating valve 23 is connected to the third input end of the first heating network heating unit 114.

[0130] Among them, the first pneumatic check valve 19 is used to prevent the first middle row steam extraction from flowing back. The first hydraulic quick-closing regulating valve 20 is used to adjust the flow, pressure and liquid level of the first middle row steam extraction, and has the function of quick closing. The first electric shut-off valve 21 is used to control the on and off of the first middle row steam extraction, that is, to control whether the first middle row steam extraction flows. The first steam supply gate valve 22 is used to switch on and off the circulation of the first middle row steam extraction. The first steam supply regulating valve 23 is used to adjust various process parameters such as the flow, pressure and temperature of the first middle row steam extraction.

[0131] It should be noted that the specific selection and material of the first pneumatic check valve 19, the first hydraulic quick-closing regulating valve 20, the first electric shut-off valve 21, the first steam supply gate valve 22 and the first steam supply regulating valve 23 can be reasonably determined according to factors such as the scale of the first cogeneration unit Z1 and the pipeline size, material and steam parameters under actual heating conditions.

[0132] In one embodiment, the first back-pressure power generation unit 113 includes: a first back-pressure steam turbine 4, a first back-pressure generator 5, and a first back-pressure generator condenser 6. The input end (steam inlet) of the first back-pressure steam turbine 4 is connected to the first output end of the first middle row steam extraction and steam supply unit 111, and the output end (exhaust outlet) of the first back-pressure steam turbine 4 is connected to the input end of the first back-pressure generator 5. The first back-pressure steam turbine 4 is used to generate mechanical energy based on the first middle row steam extraction, and the first back-pressure steam turbine 4 can also be used for heat supply. The output end (exhaust outlet) of the first back-pressure generator 5 is connected to the first input end (steam inlet) of the first back-pressure generator condenser 6, and the first back-pressure generator 5 exhausts steam to the first back-pressure generator condenser 6. The first back-pressure generator 5 is used to generate electricity based on the mechanical energy generated by the first back-pressure steam turbine 4. After the first back-pressure generator 5 generates electricity, the back pressure of the first cogeneration unit Z1 increases to 34 kPa.

[0133] In one embodiment, the second input end of the first back-pressure generator condenser 6 is connected to the first output end of the high back-pressure heating unit 117, and the output end of the first back-pressure generator condenser 6 is respectively connected to the output end of the second back-pressure power generation unit 118 and the first input end of the first heat network heating unit 114. The first back-pressure generator condenser 6 is used to cool the exhaust steam of the first back-pressure generator 5, that is, to condense the high-temperature and high-pressure steam discharged by the first back-pressure generator 5 into water, and this process is achieved by heat exchange between cooling water and condensed water. The first back-pressure generator condenser 6 is also used for energy recovery, that is, to recover the heat energy in the steam and convert it into electrical energy. By condensing the steam back into water, the heat energy in the steam is converted into electrical energy, thereby improving the energy utilization efficiency.

[0134] In one embodiment, the first heating network heating unit 114 includes: a first heating network circulating water pump small steam turbine 7 and a first heating network heater 8. The input end (steam inlet) of the first heating network circulating water pump small steam turbine 7 is connected to the third output end of the first middle row steam extraction and steam supply unit 111, and the output end of the first heating network circulating water pump small steam turbine 7 is connected to the third input end of the first heating network heater 8. The first heating network circulating water pump small steam turbine 7 is used to drive the first heating network heater 8. The exhaust steam of the first heating network circulating water pump small steam turbine 7 can enter the first heating network heater 8 to realize heat recovery and utilization, further improving the energy utilization efficiency. The first middle row steam extraction provides a driving steam source for the first heating network circulating water pump small steam turbine 7 and supplies heat to the first heating network heater 8.

[0135] In one embodiment, the first input end of the first heating network heater 8 is connected to the output end of the first back pressure power generation unit 113, the second input end of the first heating network heater 8 is connected to the second output end of the first middle row steam extraction and steam supply unit 111, and the output end of the first heating network heater 8 outputs the heating network supply water. The first heating network heater 8 is used to reheat the heating network return water heated by the high back pressure heating unit 117 based on the first middle row steam extraction, and output the heated heating network return water.

[0136] In one embodiment, the second middle row steam extraction steam supply unit 115 includes: a second intermediate pressure cylinder 9 and a second middle row steam extraction control module (valve group) 1152. The first end of the second middle row steam extraction control module 1152 is respectively connected to the exhaust outlet of the second intermediate pressure cylinder 9 and the first end of the exhaust flow regulating unit 116, the second end of the second middle row steam extraction control module 1152 is connected to the input end of the second back pressure power generation unit 118, the third end of the second middle row steam extraction control module 1152 is connected to the second end input end of the second heat network heating unit 119, and the second middle row steam extraction control module 1152 is used to control the second middle row steam extraction.

[0137] The second intermediate pressure cylinder 9 is used to further expand the low temperature and low pressure steam in the high pressure cylinder to increase the specific volume and temperature of the steam. The second low pressure cylinder 10 is used to further expand the low temperature and low pressure steam in the second intermediate pressure cylinder 9 to further increase the specific volume of the steam, thereby improving the overall efficiency of the steam turbine.

[0138] In one embodiment, the second intermediate exhaust steam extraction control module 1152 includes: a second pneumatic check valve 24, a second hydraulic quick-closing regulating valve 25, a second electric shut-off valve 26, a second steam supply gate valve 27, a second steam supply regulating valve 28, a second main steam supply pipeline arranged between the exhaust outlet of the second intermediate pressure cylinder 9 and the second input end of the second heating network heating unit 119, and a third bypass steam supply pipeline arranged between the second end of the second electric shut-off valve 26 and the input end of the second back pressure power generation unit 118.

[0139] In one embodiment, the second pneumatic check valve 24, the second hydraulic fast closing regulating valve 25, the second electric shut-off valve 26 and the second steam supply regulating valve 28 are sequentially arranged on the second main steam supply pipeline, and the second steam supply gate valve 27 is arranged on the third bypass steam supply pipeline. The second end of the second pneumatic check valve 24 is connected to the first end of the second hydraulic fast closing regulating valve 25, the second end of the second hydraulic fast closing regulating valve 25 is connected to the first end of the second electric shut-off valve 26, the second end of the second electric shut-off valve 26 and the first end of the second steam supply gate valve 27 are respectively connected to the first end of the second steam supply regulating valve 28. The second end of the second steam supply gate valve 27 is connected to the input end of the second back pressure power generation unit 118, and the second end of the second steam supply regulating valve 28 is connected to the second input end of the second heating network heating unit 119.

[0140] Among them, the second pneumatic check valve 24 is used to prevent the backflow of the second middle row extraction steam. The second hydraulic quick-closing regulating valve 25 is used to adjust the flow, pressure and liquid level of the second middle row extraction steam, and has the function of quick closing. The second electric shut-off valve 26 is used to control the on and off of the second middle row extraction steam, that is, to control whether the second middle row extraction steam flows. The second steam supply gate valve 27 is used to switch on and off the circulation of the second middle row extraction steam. The second steam supply regulating valve 28 is used to adjust various process parameters such as the flow, pressure and temperature of the second middle row extraction steam.

[0141] It should be noted that the specific selection and material of the second pneumatic check valve 24, the second hydraulic fast closing regulating valve 25, the second electric shut-off valve 26 and the second steam supply regulating valve 28 can be reasonably determined according to the scale of the second cogeneration unit Z2 and the pipeline size, material and steam parameters under actual heating conditions.

[0142] In one embodiment, the exhaust steam flow regulating unit 116 includes a connecting pipe hydraulic butterfly valve 11. The connecting pipe hydraulic butterfly valve 11 is arranged on the second exhaust steam pipeline, the first end of the connecting pipe hydraulic butterfly valve 11 is connected to the third output end of the second middle exhaust steam extraction and supply unit 115, and the second end of the connecting pipe hydraulic butterfly valve 11 is connected to the steam inlet of the second low-pressure cylinder 10. The connecting pipe hydraulic butterfly valve 11 has good flow characteristics, the flow is continuously adjustable, and can be adjusted and controlled within the flow range of 0 to 100%. The second cogeneration unit Z2 can flexibly switch between three working conditions: pure condensation, extraction condensation, and back pressure according to the actual peak regulation needs.

[0143] In one embodiment, based on different peak-shaving heating demands, the second cogeneration unit Z2 can flexibly adjust its operating conditions to achieve optimal operation under different heating demands. Different operating conditions need to be designed according to actual heating demands, mainly by adjusting the opening of the connecting pipe hydraulic butterfly valve 11 to adjust the steam inlet flow of the second low-pressure cylinder 10.

[0144] In one embodiment, the high back pressure heating unit 117 includes a high back pressure condenser 12. The first input end (heat release side inlet) of the high back pressure condenser 12 is connected to the second exhaust outlet of the second low pressure cylinder 10, the second input end (heat absorption side inlet) of the high back pressure condenser 12 is input with heat network return water, and the first output end of the high back pressure condenser 12 is respectively connected to the second input end of the first back pressure power generation unit 113 and the second input end of the second back pressure power generation unit 118 through the heat network circulating water pipeline. The second output end of the high back pressure condenser 12 is connected to the input end of the exhaust device 240, and the high back pressure condenser 12 exhausts steam to the exhaust device 240.

[0145] In one embodiment, the second back-pressure power generation unit 118 includes: a second back-pressure steam turbine 13, a second back-pressure generator 14, and a second back-pressure generator condenser 15. The input end of the second back-pressure steam turbine 13 is connected to the first output end of the second middle row steam extraction and steam supply unit 115, and the output end of the second back-pressure steam turbine 13 is connected to the input end of the second back-pressure generator 14. The second back-pressure steam turbine 13 is used to generate mechanical energy based on the second middle row steam extraction, and the second back-pressure steam turbine 13 can also be used for heat supply. The output end of the second back-pressure generator 14 is connected to the first input end of the second back-pressure generator condenser 15, and the second back-pressure generator 14 exhausts steam to the second back-pressure generator condenser 15, and the second back-pressure generator 14 is used to generate electricity based on the mechanical energy generated by the second back-pressure steam turbine 13.

[0146] In one embodiment, the second input end of the second back-pressure generator condenser 15 is connected to the first output end of the high back-pressure heating unit 117, and the output end of the second back-pressure generator condenser 15 is respectively connected to the output end of the first back-pressure power generation unit 113 and the first input end of the second heat network heating unit 119, and the second back-pressure generator condenser 15 is used to cool the exhaust steam of the second back-pressure generator 14 and recover energy.

[0147] In one embodiment, the second heating network heating unit 119 includes: a second heating network circulating water pump small steam turbine 18 and a second heating network heater 17. The input end of the second heating network circulating water pump small steam turbine 18 is connected to the second output end of the second middle row steam extraction and steam supply unit 115, and the output end of the second heating network circulating water pump small steam turbine 18 is connected to the second input end of the second heating network heater 17, and the second heating network circulating water pump small steam turbine 18 is used to drive the second heating network heater 17.

[0148] The exhaust steam of the small steam turbine 18 of the second heat network circulating water pump can enter the second heat network heater 17 to realize heat recovery and further improve energy utilization efficiency. The second intermediate exhaust steam provides a driving steam source for the small steam turbine 18 of the second heat network circulating water pump and provides heat for the second heat network heater 17.

[0149] In one embodiment, the first input end of the second heating network heater 17 is connected to the output end of the second back pressure power generation unit 118, and the output end of the second heating network heater 17 outputs the heating network supply water. The second heating network heater 17 is used to reheat the heating network return water heated by the high back pressure heating unit 117, and output the heated heating network return water.

[0150] In one embodiment, the cogeneration device 100 of low-pressure cylinder micro-output combined with high back pressure transformation also includes a heat network circulating water drive unit 120 of the first heating station. The input end of the heat network circulating water drive unit 120 is connected to the output end of the first back pressure power generation unit 113 and the output end of the second back pressure power generation unit 118 through the heat network circulating water pipeline, and the heat network return water heated by the high back pressure heating unit 117, the condensate of the first back pressure generator condenser 6, and the condensate of the second back pressure generator condenser 15 are merged and flow into the heat network circulating water drive unit 120. The first output end of the heat network circulating water drive unit 120 is connected to the first input end of the first heat network heating unit 114 through the heat network circulating water pipeline, and the second output end of the heat network circulating water drive unit 120 is connected to the first input end of the second heat network heating unit 119 through the heat network circulating water pipeline. The heat network circulating water drive unit 120 is used to provide power for the heat network return water circulation, ensuring that the heat network return water can circulate in the system according to the preset exhaust steam flow rate.

[0151] In one embodiment, the heat network circulating water driving unit 120 includes a heat network circulating water pump 16. The input end of the heat network circulating water pump 16 is connected to the output end of the first back pressure power generation unit 113 and the output end of the second back pressure power generation unit 118 through the heat network circulating water pipeline, and the heat network return water heated by the high back pressure heating unit 117, the condensate of the first back pressure generator condenser 6 and the condensate of the second back pressure generator condenser 15 are merged and flow into the heat network circulating water pump 16. The first output end of the heat network circulating water pump 16 is connected to the first input end of the first heat network heating unit 114 through the heat network circulating water pipeline, and the second output end of the heat network circulating water pump 16 is connected to the first input end of the second heat network heating unit 119 through the heat network circulating water pipeline.

[0152] In one embodiment, the first heat network circulating water pump small steam turbine 7 and the second heat network circulating water pump small steam turbine 18 can not only effectively drive the first heat network heater 8 and the second heat network heater 17 respectively, but also be suitable for driving the heat network circulating water pump 16, thereby improving the efficiency and economic benefits of the entire heating system. The first heat network circulating water pump small steam turbine 7 and the second heat network circulating water pump small steam turbine 18 are respectively connected to the heat network circulating water pump 16 (not shown in the figure) through a coupling device to achieve direct drive.

[0153] See also Figure 3 , Figure 3 2 is a schematic block diagram of a heat and power cogeneration system 200 with low-pressure cylinder micro-output combined with high back pressure transformation provided in an embodiment of the present application. Figure 3 As shown, the cogeneration system 200 with low-pressure cylinder micro-output combined with high back pressure transformation includes: a first air-cooling island 210, a second air-cooling island 220, a heat network return water supply device 230, an exhaust device 240, a first heat network water supply device 250, a second heat network water supply device 260 and a cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure transformation.

[0154] Combination Figure 2 and Figure 3 In one embodiment, the first input end of the heat and power cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure modification is connected to the output end of the heat network return water supply device 230, and the first output end of the heat and power cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure modification is connected to the input end of the first air-cooling island 210. The first air-cooling island 210 is used to reduce the exhaust steam temperature of the first low-pressure cylinder 2 through an air cooling system, so that the exhaust steam of the first low-pressure cylinder 2 is condensed into water for recycling. The second output end of the heat and power cogeneration device 100 with low-pressure cylinder micro-output combined with high back pressure modification is connected to the input end of the second air-cooling island 220, and the second air-cooling island 220 is used to reduce the exhaust steam temperature of the second low-pressure cylinder 10 through an air cooling system, so that the exhaust steam of the second low-pressure cylinder 10 is condensed into water for recycling.

[0155] In one embodiment, the third output end of the low-pressure cylinder micro-output combined with high back pressure modified cogeneration device 100 is connected to the input end of the exhaust device 240, and the exhaust device 240 is used to exhaust the exhaust steam of the high back pressure heating unit 117. The fourth output end of the low-pressure cylinder micro-output combined with high back pressure modified cogeneration device 100 is connected to the input end of the first heat network water supply device 250, and the first heat network water supply device 250 is used to provide heat network water supply to users. The fifth output end of the low-pressure cylinder micro-output combined with high back pressure modified cogeneration device 100 is connected to the input end of the second heat network water supply device 260, and the second heat network water supply device 260 is used to provide heat network water supply to users. The low-pressure cylinder micro-output combined with high back pressure modified cogeneration device 100 is used to generate electricity and provide heat to users.

[0156] See also Figure 4 , Figure 4 This is a schematic diagram of the steps of the energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application. The method is implemented based on the cogeneration device 100 of low-pressure cylinder micro-output combined with high back pressure transformation, and the method can be executed during the peak operation of heating. Figure 1 and Figure 4 , the method may include the following steps:

[0157] S401, based on the first middle exhaust steam supply unit 111 of the first cogeneration unit Z1, the first middle exhaust steam is provided to the first back pressure power generation unit 113 and the first heat network heating unit 114; based on the low pressure cylinder output regulating unit 112, the output of the first low pressure cylinder 2 is reduced, and the heat generated by the blowing of the first low pressure cylinder 2 is cooled.

[0158] Combination Figure 2 and Figure 4 According to an embodiment of the present application, the first intermediate exhaust steam supply unit 111 includes a first intermediate pressure cylinder 1, and the low pressure cylinder output regulating unit 112 includes a double valve plate heating butterfly valve 3, and the double valve plate heating butterfly valve 3 includes: a main valve plate and a small valve plate (not shown in the figure). Based on the low pressure cylinder output regulating unit 112 to reduce the output of the first low pressure cylinder 2 and cool the heat generated by the first low pressure cylinder 2, the following steps may be included:

[0159] Adjust the double valve plate heating butterfly valve 3, that is, close the main valve plate, and adjust the opening of the small valve plate to the preset opening, so that the exhaust steam of the first intermediate pressure cylinder 1 corresponding to the exhaust flow of the preset opening enters the first low-pressure cylinder 2, so as to reduce the output of the first low-pressure cylinder 2 and cool the heat generated by the blast of the first low-pressure cylinder 2. Among them, the preset opening can be determined according to the specific circumstances in the actual application scenario, and is not specifically limited here. It should be noted that in order to adjust the output of the first low-pressure cylinder 2 to a micro output, the preset opening should be as small as possible so that the exhaust flow corresponding to the preset opening is smaller.

[0160] According to an embodiment of the present application, providing the first middle exhaust steam extraction supply unit 111 of the first cogeneration unit Z1 to the first back pressure power generation unit 113 and the first heat network heating unit 114 may include the following steps:

[0161] The first intermediate exhaust steam supply unit 111 provides the first intermediate exhaust steam with the remaining exhaust steam flow to the first back pressure power generation unit 113 and the first heat network heating unit 114. The remaining exhaust steam flow is the difference between the total exhaust steam flow of the first intermediate pressure cylinder 1 and the exhaust steam flow corresponding to the preset opening.

[0162] In one embodiment, a small portion of the steam flow can be maintained to enter the first low-pressure cylinder 2, and most of the steam flow can enter the first back-pressure power generation unit 113 to generate electricity and enter the first heat network heating unit 114 to provide heat.

[0163] S402, based on the first back pressure power generation unit 113, the first middle exhaust steam is used to generate electricity and supply heat; based on the first heating network heating unit 114, the first middle exhaust steam is used to reheat the heating network return water that has been preliminarily heated by the high back pressure heating unit 117, and the heated heating network return water is output.

[0164] S403, based on the second middle exhaust steam supply unit 115 of the second cogeneration unit Z2, the second middle exhaust steam is provided to the second back pressure power generation unit 118 and the second heat network heating unit 119; based on the exhaust steam flow regulating unit 116, the exhaust steam flow input to the second low-pressure cylinder 10 is adjusted to enable the second cogeneration unit Z2 to switch between pure condensation, extraction condensation or back pressure conditions.

[0165] According to an embodiment of the present application, the second intermediate exhaust steam supply unit 115 includes a second intermediate pressure cylinder 9. Based on the exhaust steam flow rate regulating unit 116, the exhaust steam flow rate input to the second low pressure cylinder 10 is regulated so that the second cogeneration unit Z2 switches to operate under pure condensation, extraction condensation or back pressure conditions, which may include the following steps:

[0166] Based on the exhaust steam flow regulating unit 116, the exhaust steam flow of the second intermediate pressure cylinder 9 input into the second low pressure cylinder 10 is adjusted to the first preset exhaust steam flow, so that the second cogeneration unit Z2 operates under pure condensing conditions; or based on the exhaust steam flow regulating unit 116, the exhaust steam flow of the second intermediate pressure cylinder 9 input into the second low pressure cylinder 10 is adjusted to the second preset exhaust steam flow, so that the second cogeneration unit Z2 operates under extraction condensing conditions; or based on the exhaust steam flow regulating unit 116, the exhaust steam flow of the second intermediate pressure cylinder 9 input into the second low pressure cylinder 10 is adjusted to the third preset exhaust steam flow, so that the second cogeneration unit Z2 operates under back pressure conditions.

[0167] In one embodiment, based on different peak-shaving heating demands, the second cogeneration unit Z2 can flexibly adjust its operating conditions, thereby achieving optimal operation under different heating demands. Different operating conditions need to be designed according to actual heating demands, mainly by adjusting the steam inlet flow rate of the second low-pressure cylinder 10 through the exhaust steam flow rate regulating unit 116, and different steam inlet flows correspond to different operating conditions.

[0168] According to an embodiment of the present application, the second middle exhaust steam supply unit 115 based on the second cogeneration unit Z2 provides the second middle exhaust steam to the second back pressure power generation unit 118 and the second heat network heating unit 119, which may include the following steps:

[0169] The second middle row extraction steam supply unit 115 provides the second middle row extraction steam with the first remaining exhaust steam flow to the second back pressure power generation unit 118 and the second heat network heating unit 119. The first remaining exhaust steam flow is the difference between the total exhaust steam flow of the second middle row extraction steam and the first preset exhaust steam flow.

[0170] Alternatively, the second middle row extraction steam supply unit 115 provides the second middle row extraction steam of the second preset exhaust steam flow rate to the second low-pressure cylinder 10, and the second middle row extraction steam supply unit 115 provides the second back pressure power generation unit 118 and the second heat network heating unit 119 with the second middle row extraction steam of the second residual exhaust steam flow rate after entering the second low-pressure cylinder 10. The second residual exhaust steam flow rate is the difference between the total exhaust steam flow rate of the second middle row extraction steam and the second preset exhaust steam flow rate.

[0171] Alternatively, based on the second middle row extraction steam supply unit 115, the second middle row extraction steam of the third preset exhaust steam flow rate is provided to the second low-pressure cylinder 10, and based on the second middle row extraction steam supply unit 115, the second middle row extraction steam of the third residual exhaust steam flow rate after entering the second low-pressure cylinder 10 is provided to the second back pressure power generation unit 118 and the second heat network heating unit 119. The third residual exhaust steam flow rate is the difference between the total exhaust steam flow rate of the second middle row extraction steam and the third preset exhaust steam flow rate.

[0172] In one embodiment, the second middle row extraction steam supply unit 115 provides a portion of the second middle row extraction steam to the second low pressure cylinder 10 , and provides the remaining portion of the second middle row extraction steam to the second back pressure power generation unit 118 and the second heat network heating unit 119 .

[0173] S404, based on the high back pressure heating unit 117, the exhaust steam of the second low pressure cylinder 10 is used to preliminarily heat the return water of the heat network; based on the second back pressure power generation unit 118, the second middle exhaust steam is used to generate electricity and supply heat; based on the second heat network heating unit 119, the second middle exhaust steam is used to secondary heat the return water of the heat network heated by the high back pressure heating unit 117, and the heated return water of the heat network is output.

[0174] In one embodiment, the high back pressure heating unit 117 greatly improves the heating capacity of the second cogeneration unit Z2. The first cogeneration unit Z1 and the second cogeneration unit Z2 are both provided with three steps, each of which can utilize the middle exhaust steam to achieve the step-by-step utilization of the heat energy of the middle exhaust steam. The number and method of setting the steps can be determined according to the specific circumstances in the actual application scenario, and are not specifically limited here.

[0175] Among them, the first middle row steam extraction and supply unit 111 and the first low-pressure cylinder 2 are arranged at the first step of the first cogeneration unit Z1, the first back pressure power generation unit 113 is arranged at the second step of the first cogeneration unit Z1, and the first heat network heating unit 114 is arranged at the third step of the first cogeneration unit Z1. The second middle row steam extraction and supply unit 115, the second low-pressure cylinder 10 and the high back pressure heating unit 117 are arranged at the first step of the second cogeneration unit Z2, the second back pressure power generation unit 118 is arranged at the second step of the second cogeneration unit Z2, and the second heat network heating unit 119 is arranged at the third step of the second cogeneration unit Z2.

[0176] Combination Figure 2 and Figure 4 According to an embodiment of the present application, the low-pressure cylinder micro-output combined with high back pressure transformation cogeneration device 100 further includes a heat network circulating water drive unit 120, and the heat network circulating water drive unit 120 includes a heat network circulating water pump 16. The method may also include the following steps: providing power to the heat network return water circulation based on the heat network circulating water pump 16.

[0177] Combination Figure 2 and Figure 4 According to one embodiment of the present application, the first middle row steam extraction and supply unit 111 includes a first middle row steam extraction control module 1112, the first middle row steam extraction control module 1112 includes a first steam supply regulating valve 23, and the first heating network heating unit 114 includes a first heating network circulating water pump small steam turbine 7. The second middle row steam extraction and supply unit 115 includes a second middle row steam extraction control module 1152, the second middle row steam extraction control module 1152 includes a second steam supply regulating valve 28, and the second heating network heating unit 119 includes a second heating network circulating water pump small steam turbine 18. The first heating network circulating water pump small steam turbine 7 can provide a driving steam source for the heating network circulating water pump 16 alone, without the need for the second heating network circulating water pump small steam turbine 18 to provide a driving steam source for the heating network circulating water pump 16. Before providing power to the heating network return water circulation based on the heating network circulating water pump 16, the method may also include the following steps:

[0178] The first steam source amount of the first intermediate row extraction steam is calculated according to the input power of the heat network circulating water pump 16, and the second steam supply regulating valve 28 is closed to prevent the second intermediate row extraction steam from entering the second heat network circulating water pump small steam turbine 18. At the same time, the first steam supply regulating valve 23 is adjusted to allow the first intermediate row extraction steam of the first steam source amount to enter the first heat network circulating water pump small steam turbine 7. The first heat network circulating water pump small steam turbine 7 generates the first mechanical energy based on the first intermediate row extraction steam, and the first heat network circulating water pump small steam turbine 7 drives the heat network circulating water pump 16 based on the first mechanical energy.

[0179] Combination Figure 2 and Figure 4 According to another embodiment of the present application, the second heat network circulating water pump small steam turbine 18 can provide a driving steam source for the heat network circulating water pump 16 alone, without the need for the first heat network circulating water pump small steam turbine 7 to provide a driving steam source for the heat network circulating water pump 16. Before providing power to the heat network return water circulation based on the heat network circulating water pump 16, the method may also include the following steps:

[0180] The second steam source amount of the second intermediate row extraction steam is calculated according to the input power of the heat network circulating water pump 16, and the first steam supply regulating valve 23 is closed to prevent the first intermediate row extraction steam from entering the first heat network circulating water pump small steam turbine 7. At the same time, the second steam supply regulating valve 28 is adjusted to allow the second intermediate row extraction steam of the second steam source amount to enter the second heat network circulating water pump small steam turbine 18. The second heat network circulating water pump small steam turbine 18 generates the second mechanical energy based on the second intermediate row extraction steam, and the second heat network circulating water pump small steam turbine 18 drives the heat network circulating water pump 16 based on the second mechanical energy.

[0181] Combination Figure 2 and Figure 4 According to another embodiment of the present application, the first heat network circulating water pump small steam turbine 7 and the second heat network circulating water pump small steam turbine 18 can simultaneously provide a driving steam source for the heat network circulating water pump 16. The first heat network circulating water pump small steam turbine 7 and the second heat network circulating water pump small steam turbine 18 can respectively provide a part of the driving steam source for the heat network circulating water pump 16. Before providing power to the heat network return water circulation based on the heat network circulating water pump 16, the method can also include the following steps:

[0182] The first steam source quantity of the first intermediate row extraction steam and the second steam source quantity of the second intermediate row extraction steam are calculated respectively according to the input power of the heat network circulating water pump 16, and the first steam supply regulating valve 23 is adjusted so that the first intermediate row extraction steam of the first steam source quantity enters the first heat network circulating water pump small steam turbine 7. At the same time, the second steam supply regulating valve 28 is adjusted so that the second intermediate row extraction steam of the second steam source quantity enters the second heat network circulating water pump small steam turbine 18.

[0183] The first heat network circulating water pump small steam turbine 7 generates the first mechanical energy by using the first middle row steam extraction, and the second heat network circulating water pump small steam turbine 18 generates the second mechanical energy by using the second middle row steam extraction. The first heat network circulating water pump small steam turbine 7 uses the first mechanical energy, and the second heat network circulating water pump small steam turbine 18 uses the second mechanical energy to drive the heat network circulating water pump 16.

[0184] The cogeneration device 100 of low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application couples high back pressure transformation and low-pressure cylinder micro-output technology, and utilizes the high back pressure condenser of the second cogeneration unit Z2 to heat the return water of the heat network, thereby realizing the cascade heating of the high back pressure unit, and the first low-pressure cylinder 2 obtains a stronger heating capacity at the cost of sacrificing part of the output power. In addition, the middle exhaust steam extraction of the two cogeneration units realizes hierarchical utilization, and each is equipped with a group of back pressure generator sets (i.e., back pressure power generation units), and a steam pipeline is drawn from each of the middle exhaust steam extraction mother pipes to connect to two back pressure steam turbines respectively, which can increase the power generation power of the cogeneration unit, improve the thermal efficiency of the cogeneration unit, and reduce the use of high-grade heat for downgrade.

[0185] The second cogeneration unit Z2 can flexibly switch between three operating conditions: pure condensation, extraction condensation, and back pressure. According to different peak-shaving heating needs, its operating conditions can be flexibly adjusted to achieve optimal operation under different heating needs. Compared with the traditional single cogeneration technology, the flexibility of the cogeneration unit has been greatly improved. Under the condition of making full use of the waste heat of the cogeneration unit, the heating capacity is improved while the power loss is reduced, which is more conducive to improving thermal efficiency and has considerable energy saving and economic benefits.

[0186] The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation provided in the embodiment of the present application realizes cascade heating of high back pressure units, and obtains stronger heating capacity at the cost of sacrificing part of the output power. At the same time, since the operating mode switching of the second cogeneration unit Z2 has high flexibility, the exhaust steam flow entering the heat network (i.e., the flow of the second middle row extraction steam entering the second low-pressure cylinder 10) can be adjusted to meet different heat load requirements, improve the flexibility of the cogeneration unit, and greatly improve the energy utilization efficiency. In order to realize the hierarchical utilization of the middle row extraction steam, a steam pipeline is drawn from the middle row extraction mother pipe of each of the two cogeneration units, and the middle row extraction steam in the two steam pipelines is used as the steam source of the two back pressure steam turbines, which are standby for each other. The two cogeneration units are respectively equipped with a group of back pressure generator sets, and the two steam pipelines are connected to the two back pressure steam turbines, thereby increasing the power generation power of the cogeneration unit and improving the thermal efficiency of the cogeneration unit. Compared with the traditional technology of using middle exhaust steam extraction for heating, it reduces the use of high-grade heat for downgrading.

[0187] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0188] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0189] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation, characterized in that: The device comprises: a first middle row steam extraction and steam supply unit of a first cogeneration unit, a low-pressure cylinder output regulating unit, a first low-pressure cylinder, a first back-pressure power generation unit, a first heat network heating unit, and a first exhaust steam pipeline arranged between a fourth output end of the first middle row steam extraction and steam supply unit and a steam inlet of the first low-pressure cylinder, a second middle row steam extraction and steam supply unit of a second cogeneration unit, an exhaust steam flow regulating unit, a second low-pressure cylinder, a high back-pressure heating unit, a second back-pressure power generation unit, a second heat network heating unit, and a second exhaust steam pipeline arranged between a third output end of the second middle row steam extraction and steam supply unit and a steam inlet of the second low-pressure cylinder; The first output end of the first middle row steam extraction and supply unit is connected to the first input end of the first back pressure power generation unit, the second output end of the first middle row steam extraction and supply unit is connected to the second input end of the first heat network heating unit, the third output end of the first middle row steam extraction and supply unit is connected to the third input end of the first heat network heating unit, the fourth output end of the first middle row steam extraction and supply unit is connected to the first end of the low pressure cylinder output regulating unit, and the first middle row steam extraction and supply unit is used to provide the first middle row steam extraction to the first back pressure power generation unit and the first heat network heating unit; The low-pressure cylinder output regulating unit is arranged on the first exhaust pipe, the second end of the low-pressure cylinder output regulating unit is connected to the steam inlet of the first low-pressure cylinder, the exhaust outlet of the first low-pressure cylinder is connected to the input end of the first air-cooling island, and the low-pressure cylinder output regulating unit is used to reduce the output of the first low-pressure cylinder; The second input end of the first back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, the output end of the first back-pressure power generation unit is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit, and the first back-pressure power generation unit is used to generate electricity and heat based on the first intermediate exhaust steam extraction; The output end of the first heating network heating unit outputs the heating network supply water, and the first heating network heating unit is used to secondary heat the heating network return water that has been preliminarily heated by the high back pressure heating unit based on the first intermediate exhaust steam extraction, and output the heated heating network return water; The first output end of the second middle row extraction steam supply unit is connected to the first input end of the second back pressure power generation unit, the second output end of the second middle row extraction steam supply unit is connected to the second input end of the second heat network heating unit, the third output end of the second middle row extraction steam supply unit is connected to the first end of the exhaust steam flow regulating unit, and the second middle row extraction steam supply unit is used to provide the second middle row extraction steam to the second back pressure power generation unit and the second heat network heating unit; The exhaust steam flow regulating unit is arranged on the second exhaust steam pipeline, the second end of the exhaust steam flow regulating unit is connected to the steam inlet of the second low-pressure cylinder, the first exhaust steam outlet of the second low-pressure cylinder is connected to the input end of the second air-cooling island, and the exhaust steam flow regulating unit is used to regulate the exhaust steam flow input to the second low-pressure cylinder, so that the second cogeneration unit can switch to operate under pure condensation, extraction condensation or back pressure conditions; The first input end of the high back pressure heating unit is connected to the second exhaust steam outlet of the second low pressure cylinder, the second input end of the high back pressure heating unit inputs the return water of the heating network, the second output end of the high back pressure heating unit is connected to the input end of the exhaust steam device, and the high back pressure heating unit is used to preliminarily heat the return water of the heating network based on the exhaust steam of the second low pressure cylinder; The second input end of the second back-pressure power generation unit is connected to the first output end of the high back-pressure heating unit, the output end of the second back-pressure power generation unit is connected to the first input end of the second heat network heating unit, and the second back-pressure power generation unit is used to generate electricity and heat based on the second middle exhaust steam extraction; The output end of the second heating network heating unit outputs the heating network supply water. The second heating network heating unit is used to secondary heat the heating network return water heated by the high back pressure heating unit based on the second intermediate exhaust steam extraction, and output the heated heating network return water.

2. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The first middle row steam extraction and supply unit comprises: a first intermediate pressure cylinder and a first middle row steam extraction control module; The first end of the first middle row steam extraction control module is respectively connected to the exhaust outlet of the first medium-pressure cylinder and the first end of the low-pressure cylinder output regulating unit, the second end of the first middle row steam extraction control module is connected to the input end of the first back-pressure power generation unit, the third end of the first middle row steam extraction control module is connected to the second end input end of the first heat network heating unit, the fourth end of the first middle row steam extraction control module is connected to the third input end of the first heat network heating unit, and the first middle row steam extraction control module is used to control the first middle row steam extraction.

3. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The low-pressure cylinder output regulating unit comprises a double-valve plate heating butterfly valve; The double valve plate heating butterfly valve is arranged on the first exhaust steam pipe, the first end of the double valve plate heating butterfly valve is connected to the fourth output end of the first middle row steam extraction and supply unit, and the second end of the double valve plate heating butterfly valve is connected to the steam inlet of the first low-pressure cylinder.

4. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 2 is characterized in that: The first intermediate exhaust steam extraction control module includes: a first pneumatic check valve, a first hydraulic fast closing regulating valve, a first electric shut-off valve, a first steam supply gate valve, a first steam supply regulating valve, a first main steam supply pipeline arranged between the exhaust outlet of the first intermediate pressure cylinder and the second input end of the first heating network heating unit, a first bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the input end of the first back pressure power generation unit, and a second bypass steam supply pipeline arranged between the second end of the first electric shut-off valve and the third input end of the first heating network heating unit; The first pneumatic check valve, the first hydraulic fast closing regulating valve and the first electric shut-off valve are sequentially arranged on the first main steam supply pipeline, the first steam supply gate valve is arranged on the first bypass steam supply pipeline, and the first steam supply regulating valve is arranged on the second bypass steam supply pipeline; The first end of the first pneumatic check valve is connected to the first end of the low-pressure cylinder output regulating unit, the second end of the first pneumatic check valve is connected to the first end of the first hydraulic quick-closing regulating valve, the second end of the first hydraulic quick-closing regulating valve is connected to the first end of the first electric shut-off valve, the second end of the first electric shut-off valve, the first end of the first steam supply gate valve and the first end of the first steam supply regulating valve are respectively connected to the second input end of the first heating network heating unit, the second end of the first steam supply gate valve is connected to the input end of the first back pressure power generation unit, and the second end of the first steam supply regulating valve is connected to the third input end of the first heating network heating unit.

5. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The first back-pressure power generation unit comprises: a first back-pressure steam turbine, a first back-pressure generator and a first back-pressure generator condenser; The input end of the first back-pressure steam turbine is connected to the first output end of the first middle row steam extraction steam supply unit, the output end of the first back-pressure steam turbine is connected to the input end of the first back-pressure generator, and the first back-pressure steam turbine is used to generate mechanical energy based on the first middle row steam extraction; The output end of the first back-pressure generator is connected to the first input end of the first back-pressure generator condenser, and the first back-pressure generator is used to generate electricity based on the mechanical energy generated by the first back-pressure steam turbine; The second input end of the first back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output end of the first back-pressure generator condenser is respectively connected to the output end of the second back-pressure power generation unit and the first input end of the first heat network heating unit, and the first back-pressure generator condenser is used for cooling the exhaust steam of the first back-pressure generator and recovering energy.

6. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The first heating network heating unit comprises: a first heating network circulating water pump small steam turbine and a first heating network heater; The input end of the small steam turbine of the first heat network circulating water pump is connected to the third output end of the first middle row steam extraction and supply unit, and the output end of the small steam turbine of the first heat network circulating water pump is connected to the third input end of the first heat network heater, and the small steam turbine of the first heat network circulating water pump is used to drive the first heat network heater; The first input end of the first heating network heater is connected to the output end of the first back pressure power generation unit, the second input end of the first heating network heater is connected to the second output end of the first middle row steam extraction and supply unit, the output end of the first heating network heater outputs heating network supply water, and the first heating network heater is used to secondary heat the heating network return water heated by the high back pressure heating unit based on the first middle row steam extraction, and output the heated heating network return water.

7. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The second middle row extraction steam supply unit comprises: a second intermediate pressure cylinder and a second middle row extraction steam control module; The first end of the second middle exhaust steam extraction control module is respectively connected to the exhaust outlet of the second intermediate pressure cylinder and the first end of the exhaust steam flow regulating unit, the second end of the second middle exhaust steam extraction control module is connected to the input end of the second back pressure power generation unit, the third end of the second middle exhaust steam extraction control module is connected to the second end input end of the second heat network heating unit, and the second middle exhaust steam extraction control module is used to control the second middle exhaust steam extraction.

8. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 7 is characterized in that: The second intermediate exhaust steam extraction control module includes: a second pneumatic check valve, a second hydraulic fast closing regulating valve, a second electric shut-off valve, a second steam supply gate valve, a second steam supply regulating valve, a second main steam supply pipeline arranged between the exhaust outlet of the second intermediate pressure cylinder and the second input end of the second heating network heating unit, and a third bypass steam supply pipeline arranged between the second end of the second electric shut-off valve and the input end of the second back pressure power generation unit; The second pneumatic check valve, the second hydraulic fast closing regulating valve, the second electric shut-off valve and the second steam supply regulating valve are sequentially arranged on the second main steam supply pipeline, and the second steam supply gate valve is arranged on the third bypass steam supply pipeline; The second end of the second pneumatic check valve is connected to the first end of the second hydraulic quick-closing regulating valve, the second end of the second hydraulic quick-closing regulating valve is connected to the first end of the second electric shut-off valve, the second end of the second electric shut-off valve and the first end of the second steam supply gate valve are respectively connected to the first end of the second steam supply regulating valve, the second end of the second steam supply gate valve is connected to the input end of the second back pressure power generation unit, and the second end of the second steam supply regulating valve is connected to the second input end of the second heat network heating unit.

9. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The exhaust steam flow regulating unit includes a connecting pipe hydraulic butterfly valve; The connecting pipe hydraulic butterfly valve is arranged on the second exhaust steam pipeline, the first end of the connecting pipe hydraulic butterfly valve is connected to the third output end of the second middle row steam extraction and supply unit, and the second end of the connecting pipe hydraulic butterfly valve is connected to the steam inlet of the second low-pressure cylinder.

10. The cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The high back pressure heating unit comprises a high back pressure condenser; The first input end of the high back-pressure condenser is connected to the second exhaust outlet of the second low-pressure cylinder, the second input end of the high back-pressure condenser inputs return water from the heating network, the first output end of the high back-pressure condenser is respectively connected to the second input end of the first back-pressure power generation unit and the second input end of the second back-pressure power generation unit through a circulating water pipeline of the heating network, and the second output end of the high back-pressure condenser is connected to the input end of the exhaust device.

11. The heat and power cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The second back-pressure power generation unit comprises: a second back-pressure steam turbine, a second back-pressure generator and a second back-pressure generator condenser; The input end of the second back-pressure steam turbine is connected to the first output end of the second middle row steam extraction steam supply unit, the output end of the second back-pressure steam turbine is connected to the input end of the second back-pressure generator, and the second back-pressure steam turbine is used to generate mechanical energy based on the second middle row steam extraction; The output end of the second back-pressure generator is connected to the first input end of the second back-pressure generator condenser, and the second back-pressure generator is used to generate electricity based on the mechanical energy generated by the second back-pressure steam turbine; The second input end of the second back-pressure generator condenser is connected to the first output end of the high back-pressure heating unit, and the output end of the second back-pressure generator condenser is respectively connected to the output end of the first back-pressure power generation unit and the first input end of the second heat network heating unit, and the second back-pressure generator condenser is used for cooling the exhaust steam of the second back-pressure generator and energy recovery.

12. The heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation according to claim 1 is characterized in that: The second heating network heating unit comprises: a second heating network circulating water pump small steam turbine and a second heating network heater; The input end of the second heating network circulating water pump small steam turbine is connected to the second output end of the second middle row steam extraction and supply unit, the output end of the second heating network circulating water pump small steam turbine is connected to the second input end of the second heating network heater, and the second heating network circulating water pump small steam turbine is used to drive the second heating network heater; The first input end of the second heating network heater is connected to the output end of the first back pressure power generation unit, and the output end of the second heating network heater outputs the heating network supply water. The second heating network heater is used to reheat the heating network return water heated by the high back pressure heating unit and output the heated heating network return water.

13. A heat and power cogeneration device according to any one of claims 1 to 12, characterized in that: The device also includes a heat network circulating water driving unit; The input end of the heating network circulating water driving unit is connected to the output end of the first back-pressure power generation unit and the output end of the second back-pressure power generation unit through the heating network circulating water pipeline, the first output end of the heating network circulating water driving unit is connected to the first input end of the first heating network heating unit through the heating network circulating water pipeline, the second output end of the heating network circulating water driving unit is connected to the first input end of the second heating network heating unit through the heating network circulating water pipeline, and the heating network circulating water driving unit is used to provide power for the heating network return water circulation.

14. The heat and power cogeneration device of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 13 is characterized in that: The heating network circulating water driving unit comprises a heating network circulating water pump; The input end of the heating network circulating water pump is connected to the output end of the first back-pressure power generation unit and the output end of the second back-pressure power generation unit through a heating network circulating water pipeline, the first output end of the heating network circulating water pump is connected to the first input end of the first heating network heating unit through a heating network circulating water pipeline, and the second output end of the heating network circulating water pump is connected to the first input end of the second heating network heating unit through a heating network circulating water pipeline.

15. A cogeneration system with low-pressure cylinder micro-output and high back pressure transformation, characterized in that: The system comprises: a first air-cooling island, a second air-cooling island, a heat network return water supply device, a steam exhaust device, a first heat network water supply device, a second heat network water supply device, and a heat and power cogeneration device with low-pressure cylinder micro-output combined with high back pressure transformation as described in any one of claims 1 to 14; The first input end of the cogeneration device is connected to the output end of the heat network return water supply device, and the first output end of the cogeneration device is connected to the input end of the first air cooling island, and the first air cooling island is used to reduce the exhaust steam temperature of the first low-pressure cylinder so that the exhaust steam of the first low-pressure cylinder is condensed into water; The second output end of the cogeneration device is connected to the input end of the second air-cooling island, and the second air-cooling island is used to reduce the exhaust steam temperature of the second low-pressure cylinder so that the exhaust steam of the second low-pressure cylinder is condensed into water; The third output end of the cogeneration device is connected to the input end of the exhaust device, and the exhaust device is used to exhaust the exhaust steam of the high back pressure heating unit; the fourth output end of the cogeneration device is connected to the input end of the first heat network water supply device, and the first heat network water supply device is used to provide heat network water supply to users; The fifth output end of the cogeneration device is connected to the input end of the second heat network water supply device, the second heat network water supply device is used to provide heat network water supply to users, and the cogeneration device is used to generate electricity and supply heat to users.

16. A method for energy cascade utilization by combining low-pressure cylinder micro-output with high back pressure transformation, characterized in that: A heat and power cogeneration device based on a low-pressure cylinder micro-output combined with high back pressure transformation according to any one of claims 1 to 14 is implemented, and the method comprises: Based on the first middle exhaust steam supply unit of the first cogeneration unit, the first middle exhaust steam is provided to the first back pressure power generation unit and the first heat network heating unit; based on the low pressure cylinder output regulating unit, the output of the first low pressure cylinder is reduced, and the heat generated by the blast of the first low pressure cylinder is cooled; Based on the first back pressure power generation unit, the first middle exhaust steam extraction is used to generate electricity and supply heat; based on the first heat network heating unit, the first middle exhaust steam extraction is used to secondary heat the heat network return water that has been preliminarily heated by the high back pressure heating unit, and the heated heat network return water is output; Based on the second middle exhaust steam supply unit of the second cogeneration unit, the second middle exhaust steam is provided to the second back pressure power generation unit and the second heat network heating unit; based on the exhaust steam flow regulating unit, the exhaust steam flow input to the second low pressure cylinder is adjusted, so that the second cogeneration unit can switch to operate under pure condensation, extraction condensation or back pressure conditions; Based on the high back pressure heating unit, the exhaust steam of the second low pressure cylinder is used to preliminarily heat the return water of the heat network; based on the second back pressure power generation unit, the second middle exhaust steam is used to generate electricity and supply heat; based on the second heat network heating unit, the second middle exhaust steam is used to secondary heat the return water of the heat network heated by the high back pressure heating unit, and the heated return water of the heat network is output; Wherein, the first middle row steam extraction and supply unit and the first low-pressure cylinder are arranged at the first stage of the first cogeneration unit, the first back-pressure power generation unit is arranged at the second stage of the first cogeneration unit, and the first heating network heating unit is arranged at the third stage of the first cogeneration unit; The second middle row steam extraction and supply unit, the second low-pressure cylinder and the high back-pressure heating unit are arranged at the first stage of the second cogeneration unit, the second back-pressure power generation unit is arranged at the second stage of the second cogeneration unit, and the second heat network heating unit is arranged at the third stage of the second cogeneration unit.

17. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 16 is characterized in that: The first intermediate row steam extraction and supply unit includes a first intermediate pressure cylinder, the low pressure cylinder output regulating unit includes a double valve plate heating butterfly valve, and the double valve plate heating butterfly valve includes: a main valve plate and a small valve plate; based on the low pressure cylinder output regulating unit, the output of the first low pressure cylinder is reduced, and the heat generated by the first low pressure cylinder blast is cooled, including: Close the main valve plate and adjust the opening of the small valve plate to a preset opening so that the exhaust steam of the first intermediate pressure cylinder corresponding to the exhaust flow rate of the preset opening enters the first low pressure cylinder to reduce the output of the first low pressure cylinder and cool the heat generated by the blowing of the first low pressure cylinder.

18. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 17 is characterized in that: The first middle exhaust steam supply unit based on the first cogeneration unit provides the first middle exhaust steam to the first back pressure power generation unit and the first heat network heating unit, including: A first intermediate exhaust steam extraction is provided based on the first intermediate exhaust steam extraction supply unit to provide the first back pressure power generation unit and the first heat network heating unit with a remaining exhaust steam flow; wherein the remaining exhaust steam flow is the difference between the total exhaust steam flow of the first intermediate pressure cylinder and the exhaust steam flow corresponding to the preset opening.

19. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 16 is characterized in that: The second intermediate exhaust steam supply unit includes a second intermediate pressure cylinder; based on the exhaust steam flow regulating unit, the exhaust steam flow input to the second low-pressure cylinder is adjusted so that the second cogeneration unit can switch to operate under pure condensation, extraction condensation or back pressure conditions, including: Based on the exhaust steam flow rate regulating unit, regulating the exhaust steam flow rate of the second intermediate pressure cylinder input into the second low pressure cylinder to a first preset exhaust steam flow rate, so that the second cogeneration unit operates under pure condensing conditions; or adjusting the exhaust steam flow rate of the second intermediate pressure cylinder input into the second low pressure cylinder to a second preset exhaust steam flow rate based on the exhaust steam flow rate regulating unit, so that the second cogeneration unit operates under the extraction and condensation condition; Alternatively, based on the exhaust steam flow rate regulating unit, the exhaust steam flow rate of the second intermediate pressure cylinder input into the second low pressure cylinder is regulated to a third preset exhaust steam flow rate, so that the second cogeneration unit operates under back pressure conditions.

20. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 19 is characterized in that: The second middle exhaust steam supply unit based on the second cogeneration unit provides the second middle exhaust steam to the second back pressure power generation unit and the second heat network heating unit, including: Based on the second middle row extraction steam supply unit, a second middle row extraction steam with a first residual exhaust steam flow rate is provided to the second back pressure power generation unit and the second heat network heating unit; wherein the first residual exhaust steam flow rate is the difference between the total exhaust steam flow rate of the second middle row extraction steam and the first preset exhaust steam flow rate; or based on the second middle row extraction steam supply unit providing the second back pressure power generation unit and the second heat network heating unit with a second middle row extraction steam with a second residual exhaust steam flow; wherein the second residual exhaust steam flow is the difference between the total exhaust steam flow of the second middle row extraction steam and the second preset exhaust steam flow; Or based on the second middle row extraction steam supply unit, a second middle row extraction steam with a third residual exhaust steam flow is provided to the second back pressure power generation unit and the second heat network heating unit; wherein the third residual exhaust steam flow is the difference between the total exhaust steam flow of the second middle row extraction steam and the third preset exhaust steam flow.

21. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 16 is characterized in that: The cogeneration device further includes a heat network circulating water driving unit, and the heat network circulating water driving unit includes a heat network circulating water pump; the method further includes: The heating network circulating water pump provides power for the heating network return water circulation.

22. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 21 is characterized in that: The first middle row steam extraction and supply unit includes a first middle row steam extraction control module, the first middle row steam extraction control module includes a first steam supply regulating valve, and the first heating network heating unit includes a first heating network circulating water pump small steam turbine; the second middle row steam extraction and supply unit includes a second middle row steam extraction control module, the second middle row steam extraction control module includes a second steam supply regulating valve, and the second heating network heating unit includes a second heating network circulating water pump small steam turbine; Before providing power to the heat network return water circulation based on the heat network circulating water pump, the method further comprises: Calculate the first steam source amount of the first intermediate row extraction steam according to the input power of the heat network circulating water pump, close the second steam supply regulating valve to prevent the second intermediate row extraction steam from entering the second heat network circulating water pump small steam turbine, and adjust the first steam supply regulating valve to allow the first steam source amount of the first intermediate row extraction steam to enter the first heat network circulating water pump small steam turbine; Based on the first heating network circulating water pump small steam turbine, the first intermediate exhaust steam is used to generate the first mechanical energy, and based on the first heating network circulating water pump small steam turbine, the first mechanical energy is used to drive the heating network circulating water pump.

23. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 22 is characterized in that: Before providing power to the heat network return water circulation based on the heat network circulating water pump, the method further comprises: Calculate the second steam source amount of the second intermediate row extraction steam according to the input power of the heat network circulating water pump, close the first steam supply regulating valve to prevent the first intermediate row extraction steam from entering the first heat network circulating water pump small steam turbine, and adjust the second steam supply regulating valve to allow the second steam source amount of the second intermediate row extraction steam to enter the second heat network circulating water pump small steam turbine; Based on the second heating network circulating water pump small steam turbine, the second intermediate exhaust steam is used to generate second mechanical energy, and based on the second heating network circulating water pump small steam turbine, the second mechanical energy is used to drive the heating network circulating water pump.

24. The energy cascade utilization method of low-pressure cylinder micro-output combined with high back pressure transformation according to claim 22 is characterized in that: Before providing power to the heat network return water circulation based on the heat network circulating water pump, the method further comprises: Calculate the first steam source quantity of the first middle row extraction steam and the second steam source quantity of the second middle row extraction steam respectively according to the input power of the heat network circulating water pump, adjust the first steam supply regulating valve so that the first middle row extraction steam of the first steam source quantity enters the first heat network circulating water pump small steam turbine, and adjust the second steam supply regulating valve so that the second middle row extraction steam of the second steam source quantity enters the second heat network circulating water pump small steam turbine; Based on the first heat network circulating water pump small steam turbine, the first middle exhaust steam is used to generate the first mechanical energy, and based on the second heat network circulating water pump small steam turbine, the second middle exhaust steam is used to generate the second mechanical energy; The first heating network circulating water pump small turbine utilizes the first mechanical energy, and the second heating network circulating water pump small turbine utilizes the second mechanical energy to drive the heating network circulating water pump.

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