Combined heat and power generation energy cascade heat supply module and system and module selecting and matching method

Abstract

The invention provides a combined heat and power generation energy cascade heat supply module and system and a module selecting and matching method, and relates to the technical field of thermal power generating unit heat supply. Comprising a first heat exchange device, a second heat exchange device, a third heat exchange device and a fourth heat exchange device, the first heating device is used for secondarily heating heat supply network return water discharged from the first heat exchange device by utilizing intermediate exhaust steam discharged from an intermediate-pressure cylinder of the cylinder-switching modified coal-fired power generation unit to become heat supply network water supply; the steam supplementing pipeline is used for supplying reheated steam of the high-back-pressure coal-fired power generation unit and the cylinder-cut modified coal-fired power generation unit to the first heating device; a first storage part of the heat storage device is used for recycling and storing heat supply network supplied water, and a second storage part is used for storing cold water. According to the combined heat and power generation energy gradient heat supply module and system and the module selecting and matching method, the problems that in order to achieve the flexibility of linkage heat supply of multiple coal power units, heat supply coal consumption is increased during peak regulation operation of the coal power units, and heat supply economical efficiency is reduced in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal power unit heating, and in particular to a cogeneration energy cascade heating module, a cogeneration energy cascade heating system and a method for selecting a cogeneration energy cascade heating module. Background Art

[0002] When coal-fired power units undertake heating tasks, they not only need to have flexible peak-shaving capabilities, but also be able to give full play to the energy-saving advantages of large-scale cogeneration heating and increase the proportion of clean heating in society. The heating technologies currently used in the market generally have a contradiction between heating flexibility and economy: for example, low-level energy heating technology can effectively recover the low-grade exhaust steam waste heat of the unit and greatly improve the heating capacity and energy-saving benefits of the unit, but it has strong thermoelectric coupling and poor flexibility; the cylinder cutting heating technology represented by low-pressure cylinder micro-output can effectively reduce the steam intake of the low-pressure cylinder and improve the heating capacity and deep adjustment capacity of the middle exhaust, but the heating steam source is still taken from the middle exhaust steam extraction, which does not have heating economy; high-low bypass heating technology, which improves the heating capacity of the unit by cutting off part of the steam turbine work, can greatly improve the deep peak-shaving capacity of the unit, but the heating steam source is taken from the main steam, and the heating economy is extremely poor. Moreover, the improvement of the flexibility of the unit by cylinder cutting technology and high and low bypass heating technology can only increase the peak load depth of the unit, but does not have the ability to increase the peak output capacity of the unit.

[0003] At present, in order to avoid failing to meet the peak-shaving requirements of the power grid, the flexibility of heating is more considered while the economy of heating is ignored when implementing heating transformation, resulting in an increase in actual heating coal consumption under deep peak-shaving, and some even exceeding the heating energy consumption of decentralized coal-fired boilers, which is not in line with the original intention of energy saving by replacing coal-fired boilers with cogeneration for heating.

[0004] Therefore, there is an urgent need for a heating system that can take into account both heating flexibility and economy. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a cogeneration energy cascade heating module, system and module selection method, which is used to solve the problem in the prior art that in order to achieve the flexibility of coordinated heating of multiple coal-fired power units, the heating coal consumption increases during peak operation of coal-fired power units, thereby reducing the economic efficiency of heating.

[0006] In order to achieve the above-mentioned object, the present invention provides a cogeneration energy cascade heating module, which is connected to a heat network system and to a plurality of high back pressure coal-fired generator sets and a plurality of cylinder cutting and transformation coal-fired generator sets. The high back pressure coal-fired generator sets and the cylinder cutting and transformation coal-fired generator sets can supply reheat steam to the cogeneration energy cascade heating module. The cogeneration energy cascade heating module includes: The first heat exchange device connected to the water outlet of the heat network system is used to connect to the exhaust port of the low-pressure cylinder of at least one group of high back-pressure coal-fired generator sets; the low-pressure exhaust steam discharged from the low-pressure cylinder of the high back-pressure coal-fired generator set is used to preliminarily heat the heat network return water from the heat network system; The first heating device connected to the heat exchange outlet of the first heat exchange device is used to be connected to the exhaust port of the intermediate pressure cylinder of at least one group of cylinder-cutting and transformed coal-fired generator sets, and to use the intermediate exhaust steam discharged from the intermediate pressure cylinder of the cylinder-cutting and transformed coal-fired generator sets to secondary heat the heat network return water discharged from the first heat exchange device to become the heat network supply water, and the heat network supply water is discharged from the heating outlet of the first heating device; A supplementary steam pipeline is used to supply reheated steam from at least one group of high back pressure coal-fired generating units and at least one group of cylinder cutting and transformation coal-fired generating units to a first heating device through the supplementary steam pipeline, and the first heating device uses the reheated steam to heat the heat network return water discharged from the first heat exchange device to become the heat network supply water; The heat storage device comprises a first storage part and a second storage part which are connected to each other. The first storage part is connected to the heating water outlet of the first heating device and is used to recover and store the hot network water discharged from the first heating device. The second storage part is connected to the heat exchange water inlet of the first heat exchange device and is used to store the cooled hot network water from the first storage part and transport the cooled hot network water to the first heat exchange device as hot network return water.

[0007] Specifically, the supplementary steam pipeline includes a supplementary steam main line and a plurality of supplementary steam branch lines; The supplementary steam main circuit has a steam outlet and a plurality of steam inlets, the steam outlet of the supplementary steam main circuit is connected to the steam inlet of the first heating device, at least one group of high back pressure coal-fired generating sets is connected to one supplementary steam branch circuit, at least one group of cylinder cutting and transformation coal-fired generating sets is connected to another supplementary steam branch circuit, the reheated steam from the high back pressure coal-fired generating sets and the reheated steam from the cylinder transformation coal-fired generating sets enter the supplementary steam main circuit through the corresponding supplementary steam branches, and then enter the first heating device through the supplementary steam main circuit.

[0008] Specifically, it also includes: a water supply bypass pipeline, which is connected from the heat exchange outlet of the first heat exchange device to the heating outlet of the first heating device, and is connected in parallel with the heat network inlet and outlet channels of the first heating device to form a water supply bypass channel.

[0009] Specifically, a water supply bypass control valve is provided on the water supply bypass pipeline to control the on-off of the water supply bypass channel.

[0010] Specifically, it also includes: a second heating device, which is arranged between the heat exchange outlet of the first heat exchange device and the heating inlet of the first heating device. The second heating device uses the exhaust steam of the intermediate pressure cylinder and the exhaust steam of the low pressure cylinder of at least one group of high back pressure coal-fired power generation units to heat the heat network return water discharged from the heat exchange outlet of the first heat exchange device. The heat network return water auxiliary heated by the second heating device is sent to the first heating device.

[0011] Specifically, it also includes: a quality improvement device, which is connected to the steam inlet of the second heating device and the exhaust port of the medium-pressure cylinder and the exhaust port of the low-pressure cylinder of at least one group of high back-pressure coal-fired generator sets through pipelines. The quality improvement device works under the drive of the medium-exhaust steam discharged from the medium-pressure cylinder of the high back-pressure coal-fired generator set to increase the temperature and pressure of the low-exhaust steam entering the second heating device.

[0012] Specifically, it also includes: a second heat exchange device, which is connected to the exhaust port of the low-pressure cylinder of at least one group of high back-pressure coal-fired generator sets, and is used to use the low-exhaust steam discharged from the low-pressure cylinder of the high back-pressure coal-fired generator set connected thereto to heat the heat network return water discharged from the first heat exchange device.

[0013] Another aspect of the present invention provides a cogeneration energy cascade heating system, the cogeneration energy cascade heating system comprising any of the above-mentioned cogeneration energy cascade heating modules.

[0014] In another aspect, the present invention provides a method for selecting a cogeneration energy cascade heating module, which is used to select any of the above cogeneration energy cascade heating modules to heat the return water of a heating network system. The method for selecting a cogeneration energy cascade heating system comprises: Obtain the operating status of multiple high back pressure coal-fired generating units and cylinder cutting and transformation coal-fired generating units; According to the operating status of multiple high back pressure coal-fired generating units and cylinder cutting and transformation coal-fired generating units, select the cogeneration energy cascade heating module to heat the heat network return water of the heat network system; Wherein, if the high back pressure coal-fired generator set and the cylinder cutting and transformation coal-fired generator set are operated for peak load regulation, the preset heating network water supply temperature of the heating network system is compared with the actual heating network water supply temperature and the heating water inlet temperature of the first heating device, and according to the comparison result, the steam supply pipeline and / or the first heat exchange device and / or the first heating device and / or the heat storage device and / or the second heating device or the second heat exchange device are selected to be put into operation to heat the heating network return water to become the heating network supply water; If the high back pressure coal-fired generator set and the cylinder cutting and transformation coal-fired generator set are operated in conventional heating operation, the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device are selected to be put into operation according to the actual heating period to heat the heat network return water to become the heat network supply water.

[0015] Specifically, the method of comparing the preset water supply temperature of the heating network system with the actual water supply temperature of the heating network and the temperature of the heating water inlet of the first heating device, and selecting to put the supplementary steam pipeline and / or the first heat exchange device and / or the first heating device and / or the heat storage device and / or the second heating device or the second heat exchange device into operation to heat the return water of the heating network according to the comparison result, includes: When the actual water supply temperature of the heating network is greater than or equal to the preset water supply temperature of the heating network, the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device are selected to be put into operation to heat the return water of the heating network, and the excess water supply of the heating network is stored in the heat storage device; When the actual water supply temperature of the heating network is lower than the preset water supply temperature of the heating network, the heat storage device, the first heat exchange device and the first heating device are selected to be put into operation, the heat network return water is heated by the first heat exchange device and the first heating device, and the heat network supply water stored in the first storage part of the heat storage device is delivered to the heating network system; When the actual water supply temperature is still lower than the preset heating network water supply temperature after the heat storage device is put into operation, the supplementary steam pipeline, the heat storage device, the first heat exchange device and the first heating device are put into operation to increase the temperature of the heating network return water.

[0016] Specifically, the step of selecting the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device to operate to increase the temperature of the heat network return water according to the actually required heating period includes: When the heating period is in a cold period, the first heat exchange device and the first heating device are selected to work to increase the temperature of the heat network return water; When the heating period is at the beginning or end of a cold period, the first heat exchange device or the second heating device or the second heat exchange device is selected to start working to heat the return water of the heating network.

[0017] Specifically, the matching method further includes: The number of high back pressure coal-fired generating units and cylinder cutting transformation coal-fired generating units participating in the heating network return water of the heating network system is selected according to the temperature and flow rate of the heating network return water of the heating network system.

[0018] The present invention provides a combined heat and power energy cascade heating module, system and module selection method, wherein the combined heat and power energy cascade heating module is connected to a heat network system and multiple groups of high back pressure coal-fired generator sets and cylinder cutting and transformation coal-fired generator sets, a first heat exchange device is provided to be connected to the exhaust port of a low-pressure cylinder of at least one group of high back pressure coal-fired generator sets, low exhaust steam discharged from the exhaust port of the low pressure cylinder of the high back pressure coal-fired generator set is used to exchange heat with heat network return water from the heat network system to preliminarily heat the heat network return water, the preliminarily heated heat network return water is sent to the first heating device, the first heating device is connected to the exhaust port of a medium pressure cylinder of at least one group of cylinder cutting and transformation coal-fired generator sets, and the medium pressure cylinder of the cylinder cutting and transformation coal-fired generator sets is used to heat the heat network return water. The middle row steam discharged from the compression cylinder is secondary heated to heat the hot network return water discharged from the first heat exchange device. The temperature of the hot network return water after secondary heating is increased to become hot network supply water. At the same time, the reheated steam of at least one group of high back pressure coal-fired power generation units and at least one group of cylinder cutting and transformation coal-fired power generation units can be supplemented to the first heating device through the steam supplement pipeline. The reheated steam is used to supplement and heat the hot network return water to form hot network supply water. The hot network supply water can be used for heating. The hot network supply water can also be sent to the first storage part of the heat storage device for storage. The hot network supply water stored in the first storage part can also be supplied to the hot network system for heating. The second storage part can send the stored cooled hot network supply water to the first heat exchange device as hot network return water. The cogeneration energy cascade heating module, system and module selection method provided by the present invention utilize the low exhaust steam of high back pressure coal-fired generator sets and the exhaust steam of cylinder cutting modified coal-fired generator sets as well as the reheated steam supplied by the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets to cascade heat the heat network return water, and reasonably select the components involved in heating the heat network return water according to the operating state of the reheated steam of the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets, so as to not only utilize the low-grade exhaust steam of the reheated steam of the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets, but also utilize the exhaust steam waste heat as much as possible under the peak shaving state of the reheated steam of the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets, thereby improving the economic efficiency of heating, and solving the problem in the prior art that in order to achieve the flexibility of the coordinated heating of multiple coal-fired generator sets, the coal consumption for heating increases during the peak shaving operation of the coal-fired generator sets, thereby reducing the economic efficiency of heating.

[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the layout of the heat and power cogeneration energy cascade heating module provided in an embodiment of the present invention; Figure 2 is a schematic diagram of the layout of a heat and power cogeneration energy cascade heating module provided by another embodiment of the present invention; Figure 3 It is a schematic diagram of the layout of a heat and power cogeneration energy cascade heating module provided in yet another embodiment of the present invention.

[0021] Description of Reference Numerals 3-steam supply pipeline; 4-first heat exchange device; 5-first heating device; 51-inlet control valve; 6-heat storage device; 8-water supply bypass pipeline; 9-second heating device; 10-quality improvement device; 11-second heat exchange device; 81-water supply bypass control valve; 100-medium pressure cylinder of high back pressure coal-fired generator set; 200-low pressure cylinder of high back pressure coal-fired generator set; 300-medium pressure cylinder of coal-fired generator set with cylinder cutting and transformation; 400-low pressure cylinder of coal-fired generator set with cylinder cutting and transformation. DETAILED DESCRIPTION

[0022] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0023] Figure 1 It is a schematic diagram of the layout of a heat and power cogeneration energy cascade heating module; Figure 2 It is a schematic diagram of the layout of another combined heat and power energy cascade heating module; Figure 3 This is a schematic diagram of the layout of a heat and power cogeneration energy cascade heating module. Figure 1-Figure 3 As shown, the present invention provides a cogeneration energy cascade heating module on one hand, which is connected to a heat network system and to a plurality of high back pressure coal-fired generator sets and a plurality of cylinder cutting and transformation coal-fired generator sets, and the high back pressure coal-fired generator sets and the cylinder cutting and transformation coal-fired generator sets can supply reheat steam to the cogeneration energy cascade heating module, and the cogeneration energy cascade heating module includes: The first heat exchange device 4 connected to the water outlet of the heat network system is used to be connected to the exhaust port of the low-pressure cylinder 200 of at least one group of high back-pressure coal-fired generator sets; the low exhaust steam discharged from the low-pressure cylinder 200 of the group of high back-pressure coal-fired generator sets is used to preliminarily heat the heat network return water from the heat network system; The first heating device 5 connected to the heat exchange water outlet of the first heat exchange device 4 is used to be connected to the exhaust port of the intermediate pressure cylinder 300 of at least one group of cylinder-cutting and reforming coal-fired generator sets, and the intermediate exhaust steam discharged from the intermediate pressure cylinder 300 of the cylinder-cutting and reforming coal-fired generator sets is used to secondary heat the heat network return water discharged from the first heat exchange device 4 to become the heat network supply water, and the heat network supply water is discharged from the heating water outlet of the first heating device 5; The supplementary steam pipeline 3 is used to supply the reheated steam from at least one group of high back pressure coal-fired generating units and at least one group of cylinder cutting and transformation coal-fired generating units to the first heating device 5 through the supplementary steam pipeline 3. The first heating device 5 uses the reheated steam to heat the heat network return water discharged from the first heat exchange device 4 to become the heat network supply water; The heat storage device 6 has a first storage part and a second storage part that are connected to each other. The first storage part is connected to the heating water outlet of the first heating device 5, and is used to recover and store the hot network water discharged from the first heating device 5; the second storage part is connected to the heat exchange water inlet of the first heat exchange device 4, and is used to store the cooled hot network water from the first storage part, and transport the cooled hot network water as hot network return water to the first heat exchange device 4.

[0024] The cogeneration energy cascade heating module provided by the present invention is connected to multiple groups of high back pressure coal-fired generator sets and multiple groups of cylinder cutting and transformation coal-fired generator sets. Each group of high back pressure coal-fired generator sets supplies reheated steam to the cogeneration energy cascade heating module via its high and low pressure bypass. Each group of cylinder cutting and transformation coal-fired generator sets supplies reheated steam to the cogeneration energy cascade heating module via its high and low pressure bypass. A first heat exchange device 4 and a first heating device 5 are provided. Return water from the heat network is sequentially fed into the first heat exchange device 4 and the first heating device 5. The first heat exchange device 4 is connected to the exhaust port of the low pressure cylinder 200 of at least one group of high back pressure coal-fired generator sets. The first heating device 5 is connected to the exhaust port of the low pressure cylinder 200 of the first heating device 5. 5 is connected to the exhaust port of the intermediate pressure cylinder 300 of at least one group of cylinder cutting and transformation coal-fired generator sets, and the heat network return water enters the first heat exchange device 4 and exchanges heat with the low exhaust steam discharged from the low pressure cylinder 200 of the high back pressure coal-fired generator set connected thereto, and the heat network return water absorbs the waste heat of the low exhaust steam of the low pressure cylinder 200 of the high back pressure coal-fired generator set, and preliminarily heats the heat network return water by the low exhaust steam, and the heat network return water is discharged from the first heat exchange device 4 after being preliminarily heated and then enters the first heating device 5, and the heat network return water discharged from the first heat exchange device 4 exchanges heat with the low exhaust steam from at least one group of cylinder cutting and transformation coal-fired generator sets in the first heating device 5. The middle row steam discharged from the middle pressure cylinder 300 is heat exchanged, and the heat network return water absorbs the waste heat of the middle row steam of the middle pressure cylinder 300 of the cylinder-cutting coal-fired generator set again. In addition to being supplied to the first heating device 5, the middle row steam of the middle pressure cylinder 300 of the cylinder-cutting coal-fired generator set is also supplied to the low pressure cylinder 400 of the cylinder-cutting coal-fired generator set for the cylinder-cutting coal-fired generator set to do work. The heat network return water is heated by the middle row steam for the second time, so that the heat network return water is heated to become the heat network supply water, and the heat network supply water can be returned to the heat network system for heating; the first storage part of the heat storage device 6 can store the heat network supply water, that is, store thermal energy, to avoid energy The first heat exchanger 4 and the first heating device 5 are used to heat the water supply of the heating network, and the second heat exchanger 4 and the first heating device 5 are used to heat the water supply of the heating network.

[0025] In one embodiment, Figure 1 As shown, the supplementary steam pipeline 3 includes a supplementary steam main line 31 and a plurality of supplementary steam branch lines 32; The supplementary steam main path 31 has a steam outlet and a plurality of steam inlets. The steam outlet of the supplementary steam main path 31 is connected to the steam inlet of the first heating device 5. At least one group of high back pressure coal-fired power generation units is connected to one supplementary steam branch path 32. At least one group of cylinder cutting and transformation coal-fired power generation units is connected to another supplementary steam branch path 32. The reheated steam from the high back pressure coal-fired power generation units and the reheated steam from the cylinder cutting and transformation coal-fired power generation units enter the supplementary steam main path 31 through the corresponding supplementary steam branch paths 32, and then enter the first heating device 5 through the supplementary steam main path 31.

[0026] The high back pressure coal-fired generator set supplies reheat steam to the cogeneration energy cascade heating module through its high and low pressure bypass, and the cylinder cutting coal-fired generator set supplies reheat steam to the cogeneration energy cascade heating module through its high and low pressure bypass. The high and low pressure bypass of the high back pressure coal-fired generator set transports reheat steam to the steam supplement main line 31 through one steam supplement branch line 32, and the reheat steam of the cylinder cutting coal-fired generator set transports reheat steam to the steam supplement main line 31 through another steam supplement branch line 32. The reheat steam from the high back pressure coal-fired generator set and the reheat steam from the cylinder cutting coal-fired generator set merge in the steam supplement main line 31 and then enter the first heating device 5.

[0027] The module also includes: a water supply bypass pipe 8, which is connected from the heat exchange outlet of the first heat exchange device 4 to the heating outlet of the first heating device 5, and is connected in parallel with the heat network inlet and outlet channels of the first heating device 5 to form a water supply bypass channel.

[0028] A water supply bypass control valve 81 is provided on the water supply bypass pipeline 8 to control the on-off of the water supply bypass channel.

[0029] The return water from the heat network flows through the first heat exchange device 4 and the first heating device 5 in sequence. The first heat exchange device 4 is a condenser, and the first heating device 5 is a peak heater. The first heat exchange device 4 extracts low-discharge steam from the low-pressure cylinder 200 of at least one group of high-back-pressure coal-fired power generation units to exchange heat with the return water from the heat network. The return water from the heat network absorbs the waste heat of the low-grade exhaust steam and low-discharge steam, and then enters the first heating device 5. The first heating device 5 can extract the middle-discharge steam from the medium-pressure cylinder 300 of at least one group of cylinder-cutting and transformed coal-fired power generation units to exchange heat with the return water from the heat network discharged from the first heat exchange device 4. The return water from the heat network absorbs the heat of the middle-discharge steam again, so that the return water from the heat network is heated again to become the supply water for the heat network to supply heat to the outside. The first heating device 5 can also exchange the reheated steam transported by the supplementary steam pipeline 3 with the reheated steam from the first heat exchange device 4 is used for heat exchange with the return water from the hot network, thereby increasing the temperature of the return water from the hot network. A water supply bypass pipe 8 is provided to be connected with the heat exchange outlet of the first heat exchange device 4 and the heating outlet of the first heating device 5. In this way, when the temperature of the return water from the hot network heated by the first heat exchange device 4 can reach the temperature of the supply water from the hot network, the return water from the hot network discharged from the first heat exchange device 4 can flow through the water supply bypass pipe 8 and then enter the hot network system for heating or be sent to the first storage part of the heat storage device 6 for storage, thereby avoiding the waste caused by the return water from the hot network discharged from the first heat exchange device 4 flowing through the first heating device 5 again. A water supply bypass control valve 81 is provided on the water supply bypass pipe 8 to control the on-off of the return water flowing through the water supply bypass channel, that is, to control the flow state of the return water from the hot network discharged from the first heat exchange device 4 in the water supply bypass pipe 8, as shown in FIG. Figure 1-Figure 3 As shown, an inlet control valve 51 is arranged at the heating water inlet of the first heating device 5, and the inlet control valve 51 is used to control the flow state of the hot network return water discharged from the first heat exchange device 4 in the connecting pipe between the heat exchange outlet of the first heat exchange device 4 and the heating water inlet of the first heating device 5.

[0030] In another embodiment, if Figure 2 As shown, the module also includes: a second heating device 9, which is arranged between the heat exchange outlet of the first heat exchange device 4 and the heating inlet of the first heating device 5. The second heating device 9 uses the low-exhaust steam discharged from the low-pressure cylinder 200 of at least one group of high back-pressure coal-fired power generation units to auxiliary heat the heat network return water discharged from the heat exchange outlet of the first heat exchange device 4. The heat network return water auxiliary heated by the second heating device 9 is sent to the first heating device 5.

[0031] The module also includes: a quality improvement device 10, which is connected to the steam inlet of the second heating device 9 and the exhaust port of the intermediate pressure cylinder 100 and the exhaust port of the low pressure cylinder 200 of at least one group of high back pressure coal-fired generator sets through pipelines. The quality improvement device 10 works under the drive of the intermediate exhaust steam discharged from the intermediate pressure cylinder 100 of the high back pressure coal-fired generator set to increase the temperature and pressure of the low exhaust steam entering the second heating device 9.

[0032] In order to make better use of low-quality exhaust steam, such as Figure 2 As shown, the return water from the hot network first enters the first heat exchange device 4, and the first heat exchange device 4 extracts the low-discharge steam of the low-pressure cylinder 200 of the high-back-pressure coal-fired generator set to exchange heat with the return water from the hot network to preliminarily heat the return water from the hot network. The preliminarily heated return water from the hot network can first enter the second heating device 9 before entering the first heating device 5, and the medium-discharge steam is transported to the upgrading device 10 through the medium-pressure cylinder 100 of the high-back-pressure coal-fired generator set to drive the upgrading device 10 to work, and the temperature and pressure of the low-discharge steam of the low-pressure cylinder 200 of the high-back-pressure coal-fired generator set entering the second heating device 9 are increased by the upgrading device 10. In this way, after the return water from the hot network discharged from the first heat exchange device 4 enters the second heating device 9, the second heating device 9 uses the upgraded low-discharge steam to exchange heat with the return water from the hot network, thereby heating the return water from the first heat exchange device 4, and the return water from the second heating device 9 is sent to the first heating device 5 to exchange heat with the medium-discharge steam of the medium-pressure cylinder 300 of the cylinder-cutting coal-fired generator set. The first heating device 5 can also be sent into the first heating device 5 through the reheated steam of the high back pressure coal-fired generator set and the reheated steam of the cylinder cutting and transformation coal-fired generator set through the supplementary steam pipeline 3. The reheated steam enters the first heating device 5 and exchanges heat with the heat network return water discharged from the second heating device 9, thereby increasing the temperature of the heat network return water. A water supply bypass pipeline 8 is set to be connected with the heating water outlet of the first heating device 5 and the water outlet of the second heating device 9. In this way, when the temperature of the heat network return water heated by the second heating device 9 can meet the preset temperature of the heat network water supply, the heat network return water discharged from the second heating device 9 can flow through the water supply bypass pipeline 8 and enter the heat network system for heating or enter the first storage part of the heat storage device 6 for storage, so as to avoid the heat network return water discharged from the second heating device 9 flowing through the first heating device 5 again. A water supply bypass control valve 81 is set on the water supply bypass pipeline 8 to control the on-off of the water supply bypass channel, that is, to control the flow state of the heat network return water discharged from the second heating device 9 in the water supply bypass pipeline 8.

[0033] In yet another embodiment, Figure 3 As shown, it also includes: a second heat exchange device 11, which is connected to the exhaust port of the low-pressure cylinder 200 of at least one group of high back-pressure coal-fired power generation sets, and is used to heat the heat network return water discharged from the first heat exchange device 4 using the low-pressure steam discharged from the low-pressure cylinder 200 of the high back-pressure coal-fired power generation set connected thereto.

[0034] The heat network return water of the heat network system can be used in the first heat exchange device 4 to extract the low exhaust steam of the low pressure cylinder 200 of one or more groups of high back pressure coal-fired generator sets and exchange heat with the heat network return water flowing through to preliminarily heat the heat network return water. The heat network return water discharged from the first heat exchange device 4 enters the second heat exchange device 11. The second heat exchange device 11 extracts the low exhaust steam of the low pressure cylinder 200 of at least one group of high back pressure coal-fired generator sets to heat the heat network return water discharged from the first heat exchange device 4. The second heat exchange device 11 can also extract the low exhaust steam of the low pressure cylinder 200 of multiple groups of high back pressure coal-fired generator sets. The low-discharge steam heats the return water of the hot network discharged from the first heat exchange device 4. When the temperature of the return water of the hot network discharged from the second heat exchange device 11 is lower than the preset temperature of the hot network supply water, the return water of the hot network discharged from the second heat exchange device 11 enters the first heating device 5. The first heating device 5 extracts the middle-discharge steam discharged from the middle-pressure cylinder 300 of the cylinder-cutting coal-fired generator set to heat the return water of the hot network discharged from the second heat exchange device 11. The return water of the hot network is heated step by step by the first heat exchange device 4, the second heat exchange device 11 and the first heating device 5 to become the supply water of the hot network for heating. The first heating device 5 can also transport the reheated steam flowing in the high back pressure coal-fired generator set and the cylinder-cutting coal-fired generator set through the supplementary steam pipeline 3 to enter the first heating device 5 to exchange heat with the return water of the hot network discharged from the second heat exchange device 11, thereby increasing the temperature of the return water of the hot network. A water supply bypass pipe 8 is connected between the heating water outlet of the first heating device 5 and the water outlet of the second heat exchange device 11. When the temperature of the heat network return water discharged from the second heat exchange device 11 meets the preset heat network water supply temperature, the heat network return water discharged from the second heat exchange device 11 can flow through the water supply bypass pipe 8 and enter the heat network system for heating or enter the first storage part of the heat storage device 6 for storage, avoiding flowing through the first heating device 5 again. A water supply bypass control valve 81 is provided on the water supply bypass pipe 8 to control the on-off of the water flowing through the water supply bypass channel, that is, to control the flow state of the heat network return water discharged from the second heat exchange device 11 in the water supply bypass pipe 8.

[0035] like Figure 1-Figure 3 As shown, when the actual heating network water supply temperature is higher than the preset heating network water supply temperature, part of the heating network water supply can be stored by the heat storage device 6.

[0036] Another aspect of the present invention provides a cogeneration energy cascade heating system, wherein the cogeneration energy cascade heating system comprises any of the above-mentioned cogeneration energy cascade heating modules.

[0037] In another aspect, the present invention provides a method for selecting a cogeneration energy cascade heating module, which is used to select any of the above-mentioned cogeneration energy cascade heating modules to heat the heat network return water of the heat network system, and the method for selecting the cogeneration energy cascade heating module comprises: Obtain the operating status of high back pressure coal-fired generator sets and cylinder cutting transformation coal-fired generator sets; According to the operating status of high back pressure coal-fired generator sets and cylinder cutting and transformation coal-fired generator sets, select the cogeneration energy cascade heating module to heat the heat network return water of the heat network system; Wherein, if the high back pressure coal-fired generating set and the cylinder cutting and transformation coal-fired generating set are operated for peak load regulation, the preset heating network water supply temperature of the heating network system and the actual heating network water supply temperature are compared, and the supplementary steam pipeline and / or the heat storage device and / or the second heating device or the second heat exchange device are selected to be put into operation according to the comparison result to heat the heating network return water to become the heating network supply water; If the coal-fired power unit is in normal heating operation, the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device is selected to be put into operation according to the actual heating period to heat the heat network return water to become the heat network supply water.

[0038] Specifically, the method of comparing the preset heating network water supply temperature of the heating network system with the actual heating network water supply temperature, and selecting to put the supplementary steam pipeline and / or the heat storage device and / or the second heating device or the second heat exchange device into operation to heat the heating network return water according to the comparison result, includes: When the actual heating network water supply temperature is greater than or equal to the preset heating network water supply temperature, the first heat exchange device and / or the second heating device or the second heat exchange device is selected to be put into operation to heat the heating network return water to form heating network water supply, and the excess heating network water supply is stored in the heat storage device; When the actual heating network water supply temperature is lower than the preset heating network water supply temperature, the supplementary steam pipeline or the heat storage device and the first heat exchange device and the first heating device are selected to be put into operation to increase the temperature of the heating network return water.

[0039] Specifically, the step of selecting the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device to operate to increase the temperature of the heat network return water according to the actually required heating period includes: When the heating period is in a cold period, the first heat exchange device and the first heating device are selected to be put into operation to increase the temperature of the heat network return water; When the heating period is at the beginning or end of a cold period, the first heat exchange device or the second heating device or the second heat exchange device is selected to start working to heat the return water of the heating network.

[0040] The matching method further comprises: The number of high back pressure coal-fired generating units and cylinder cutting transformation coal-fired generating units participating in the heating network return water of the heating network system is selected according to the temperature and flow rate of the heating network return water of the heating network system.

[0041] In order to reasonably select the combined heat and power energy cascade heating module to heat the heat network return water, the combined heat and power capacity cascade heating module is selected after obtaining the operating status of multiple groups of high back pressure coal-fired generating sets and cylinder cutting and transformation coal-fired generating sets. If the high back pressure coal-fired generating sets and cylinder cutting and transformation coal-fired generating sets are operated for peak shaving, when flexible peak shaving is required, the heat network water supply temperature is monitored in real time, and the actual heat network water supply temperature is compared with the preset heat network water supply temperature. When the actual heat network water supply temperature is greater than or equal to the preset heat network water supply temperature, the heat storage device is selected to be put into operation to pass the heat storage. The device stores excess water supply from the heating network; when the actual water supply temperature of the heating network is lower than the preset water supply temperature of the heating network, the heat storage device is selected to be put into operation, that is, the water supply from the heating network stored in the heat storage device is transported to the heating network system for heating; when the actual water supply temperature of the heating network is still lower than the preset water supply temperature of the heating network after the heat storage device is put into operation, the supplementary steam pipeline is put into operation to participate in the work of heating the return water of the heating network, and the supplementary steam pipeline extracts the reheated steam from at least one group of high back pressure coal-fired power generation units and at least one group of cylinder cutting and transformation coal-fired power generation units and sends it to the first heating device for heating the return water of the heating network.

[0042] If the high back pressure coal-fired power generation unit and the cylinder cutting and transformation coal-fired power generation unit are in normal heating operation, there is no need to put the supplementary steam pipeline into operation. In the cold period, when the return water temperature of the hot network heated by the first heat exchanger is lower than the required water supply temperature, the first heating device and / or the second heating device or the second heat exchanger is put into operation to heat the return water of the hot network through the first heat exchanger and the first heating device and / or the second heating device or the second heat exchanger. In this way, the return water of the hot network flows through the first heat exchanger and the first heating device in sequence, the return water of the hot network flows through the first heat exchanger, the second heating device and the first heating device in sequence, and the return water of the hot network flows through the first heat exchanger, the second heat exchanger and the first heating device in sequence, and the return water of the hot network flows through the first heat exchanger, the second heat exchanger and the first heating device in sequence, and the return water of the hot network flows through the first heat exchanger, the second heat exchanger and the first heating device in sequence, and the first heat exchanger preliminarily heats the hot network through the first heat exchanger The return water is then heated for the second time by the second heat exchange device or the second heating device, and finally the return water of the hot network is heated by the first heating device to become the supply water of the hot network. In the cold period, the first heating device and the first heating device and / or the second heating device or the second heat exchange device are put into use to heat the return water of the hot network, which can more quickly heat the return water of the hot network to the required temperature. In the early or late cold period, when the return water temperature of the hot network heated by the first heat exchange device is higher than or close to the required supply water temperature, the first heat exchange device can be selected to be put into use, and the return water of the hot network flows through the first heat exchange device to heat the return water of the hot network through low-discharge steam. At this time, the first heating device, the second heating device and the second heat exchange device do not participate in the heating of the return water of the hot network.

[0043] In practical applications, the number of high back-pressure coal-fired generating units and cylinder-cutting coal-fired generating units participating in heating the return water of the heating network is selected according to the flow rate and temperature of the return water of the heating network. If the flow rate of the return water of the heating network is large and the water temperature is low, extracting the low exhaust steam of a high back-pressure coal-fired generating unit and the middle exhaust steam of a cylinder-cutting coal-fired generating unit cannot heat the return water of the heating network to the preset heating network water supply temperature. The number of high back-pressure coal-fired generating units and cylinder-cutting coal-fired generating units participating in heating the return water of the heating network can be increased to meet the heating requirements of the heating network system.

[0044] The present invention provides a combined heat and power energy cascade heating module, system and module selection method, wherein the combined heat and power energy cascade heating module is connected to a heat network system and multiple groups of high back pressure coal-fired generator sets and cylinder cutting and transformation coal-fired generator sets, a first heat exchange device is provided to be connected to the exhaust port of a low-pressure cylinder of at least one group of high back pressure coal-fired generator sets, low exhaust steam discharged from the exhaust port of the low pressure cylinder of the high back pressure coal-fired generator set is used to exchange heat with heat network return water from the heat network system to preliminarily heat the heat network return water, the preliminarily heated heat network return water is sent to the first heating device, the first heating device is connected to the exhaust port of a medium pressure cylinder of at least one group of cylinder cutting and transformation coal-fired generator sets, and the medium pressure cylinder of the cylinder cutting and transformation coal-fired generator sets is used to heat the heat network return water. The middle row steam discharged from the compression cylinder is secondary heated to heat the hot network return water discharged from the first heat exchange device. The temperature of the hot network return water after secondary heating is increased to become hot network supply water. At the same time, the reheated steam of at least one group of high back pressure coal-fired power generation units and at least one group of cylinder cutting and transformation coal-fired power generation units can be supplemented to the first heating device through the steam supplement pipeline. The reheated steam is used to supplement and heat the hot network return water to form hot network supply water. The hot network supply water can be used for heating. The hot network supply water can also be sent to the first storage part of the heat storage device for storage. The hot network supply water stored in the first storage part can also be supplied to the hot network system for heating. The second storage part can send the stored cooled hot network supply water to the first heat exchange device as hot network return water. The cogeneration energy cascade heating module, system and module selection method provided by the present invention utilize the low exhaust steam of high back pressure coal-fired generator sets and the exhaust steam of cylinder cutting modified coal-fired generator sets as well as the reheated steam supplied by the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets to cascade heat the heat network return water, and reasonably select the components involved in heating the heat network return water according to the operating state of the reheated steam of the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets, so as to not only utilize the low-grade exhaust steam of the reheated steam of the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets, but also utilize the exhaust steam waste heat as much as possible under the peak shaving state of the reheated steam of the high back pressure coal-fired generator sets and the cylinder cutting modified coal-fired generator sets, thereby improving the economic efficiency of heating, and solving the problem in the prior art that in order to achieve the flexibility of the coordinated heating of multiple coal-fired generator sets, the coal consumption for heating increases during the peak shaving operation of the coal-fired generator sets, thereby reducing the economic efficiency of heating.

[0045] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical scheme of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0046] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0047] In addition, various implementation modes of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed by the embodiments of the present invention.

Claims

1. A heat and power cogeneration energy cascade heating module, connected to a heat network system and to multiple groups of high back pressure coal-fired generator sets and multiple groups of cylinder cutting and transformation coal-fired generator sets, the high back pressure coal-fired generator sets and the cylinder cutting and transformation coal-fired generator sets can supply reheat steam to the heat and power cogeneration energy cascade heating module, characterized in that: The cogeneration energy cascade heating module comprises: A first heat exchange device (4) connected to the water outlet of the heat network system is used to connect to the exhaust port of the low-pressure cylinder (200) of at least one group of high back-pressure coal-fired generator sets; low-pressure exhaust steam discharged from the low-pressure cylinder (200) of the high back-pressure coal-fired generator sets is used to preliminarily heat the heat network return water from the heat network system; A first heating device (5) connected to the heat exchange water outlet of the first heat exchange device (4) is used to be connected to the exhaust port of the intermediate pressure cylinder (300) of at least one group of cylinder-cutting and reforming coal-fired generator sets, and to use the intermediate exhaust steam discharged from the intermediate pressure cylinder (300) of the cylinder-cutting and reforming coal-fired generator sets to secondary heat the heat network return water discharged from the first heat exchange device (4) to become heat network supply water, and the heat network supply water is discharged from the heating water outlet of the first heating device (5); A supplementary steam pipeline (3) is used to supply reheated steam from at least one group of high back pressure coal-fired power generation units and at least one group of cylinder cutting and transformation coal-fired power generation units to a first heating device (5) via the supplementary steam pipeline (3); the first heating device (5) uses the reheated steam to heat the heat network return water discharged from the first heat exchange device (4) to produce heat network supply water; The heat storage device (6) comprises a first storage part and a second storage part which are connected to each other, the first storage part being connected to the heating water outlet of the first heating device (5) and being used to recover and store the heating network water discharged from the first heating device (5); the second storage part being connected to the heat exchange water inlet of the first heat exchange device (4) and being used to store the cooling heating network water from the first storage part and conveying the cooling heating network water as heating network return water to the first heat exchange device (4).

2. The combined heat and power energy cascade heating module according to claim 1, characterized in that: The supplementary steam pipeline (3) comprises a supplementary steam main line (31) and a plurality of supplementary steam branch lines (32); The main supplementary steam path (31) has a steam outlet and a plurality of steam inlets. The steam outlet of the main supplementary steam path (31) is connected to the steam inlet of the first heating device (5). At least one group of high back pressure coal-fired power generation units is connected to one supplementary steam branch path (32). At least one group of cylinder cutting and transformation coal-fired power generation units is connected to another supplementary steam branch path (32). The reheated steam from the high back pressure coal-fired power generation units and the reheated steam from the cylinder cutting and transformation coal-fired power generation units enter the main supplementary steam path (31) through the corresponding supplementary steam branch paths (32), and then enter the first heating device (5) through the main supplementary steam path (31).

3. The heat and power cogeneration energy cascade heating module according to claim 2, characterized in that: Also includes: A water supply bypass pipe (8) is connected from the heat exchange outlet of the first heat exchange device (4) to the heating outlet of the first heating device (5), and is connected in parallel with the heat network water inlet and outlet channels of the first heating device (5) to form a water supply bypass channel (8).

4. The heat and power cogeneration energy cascade heating module according to claim 3, characterized in that: A water supply bypass control valve (81) is provided on the water supply bypass pipeline (8) for controlling the on-off of the water supply bypass channel.

5. The heat and power cogeneration energy cascade heating module according to claim 4, characterized in that: Also includes: The second heating device (9) is arranged between the heat exchange outlet of the first heat exchange device (4) and the heating inlet of the first heating device (5). The second heating device (9) uses the exhaust steam of the intermediate pressure cylinder (100) and the exhaust steam of the low pressure cylinder (200) of at least one group of high back pressure coal-fired power generation units to heat the heat network return water discharged from the heat exchange outlet of the first heat exchange device (4). The heat network return water auxiliary-heated by the second heating device (9) is sent to the first heating device (5).

6. The heat and power cogeneration energy cascade heating module according to claim 5, characterized in that: Also includes: The steam quality improvement device (10) is connected to the steam inlet of the second heating device (9) and the steam exhaust port of the intermediate pressure cylinder (100) and the steam exhaust port of the low pressure cylinder (200) of at least one group of high back pressure coal-fired power generation sets through pipelines. The steam quality improvement device (10) is driven by the intermediate exhaust steam discharged from the intermediate pressure cylinder (100) of the high back pressure coal-fired power generation set to increase the temperature and pressure of the low exhaust steam entering the second heating device (9).

7. The heat and power cogeneration energy cascade heating module according to claim 4, characterized in that: Also includes: The second heat exchange device (11) is connected to the exhaust port of the low-pressure cylinder (200) of at least one group of high back-pressure coal-fired power generation sets, and is used to heat the heat network return water discharged from the first heat exchange device (4) using the low-pressure exhaust steam discharged from the low-pressure cylinder (200) of the high back-pressure coal-fired power generation sets connected thereto.

8. A heat and power cogeneration energy cascade heating system, characterized in that: The cogeneration energy cascade heating system comprises the cogeneration energy cascade heating module as described in any one of claims 1-7.

9. A method for selecting a cogeneration energy cascade heating module, used for selecting the cogeneration energy cascade heating module according to any one of claims 1 to 7 to heat the return water of a heating network system, characterized in that: The method for selecting the cogeneration energy cascade heating module includes: Obtain the operating status of multiple high back pressure coal-fired generating units and cylinder cutting and transformation coal-fired generating units; According to the operating status of multiple high back pressure coal-fired generating units and cylinder cutting and transformation coal-fired generating units, select the cogeneration energy cascade heating module to heat the heat network return water of the heat network system; Wherein, if the high back pressure coal-fired generator set and the cylinder cutting and transformation coal-fired generator set are operated for peak load regulation, the preset heating network water supply temperature of the heating network system is compared with the actual heating network water supply temperature and the heating water inlet temperature of the first heating device, and according to the comparison result, the steam supply pipeline and / or the first heat exchange device and / or the first heating device and / or the heat storage device and / or the second heating device or the second heat exchange device are selected to be put into operation to heat the heating network return water to become the heating network supply water; If the high back pressure coal-fired generator set and the cylinder cutting and transformation coal-fired generator set are operated in conventional heating operation, the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device are selected to be put into operation according to the actual heating period to heat the heat network return water to become the heat network supply water.

10. The method for selecting a heat and power cogeneration energy cascade heating module according to claim 9, characterized in that: The method of comparing the preset water supply temperature of the heating network system with the actual water supply temperature of the heating network and the temperature of the heating water inlet of the first heating device, and selecting to put the supplementary steam pipeline and / or the first heat exchange device and / or the first heating device and / or the heat storage device and / or the second heating device or the second heat exchange device into operation to heat the return water of the heating network according to the comparison result, comprises: When the actual water supply temperature of the heating network is greater than or equal to the preset water supply temperature of the heating network, the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device are selected to be put into operation to heat the return water of the heating network, and the excess water supply of the heating network is stored in the heat storage device; When the actual water supply temperature of the heating network is lower than the preset water supply temperature of the heating network, the heat storage device, the first heat exchange device and the first heating device are selected to be put into operation, the heat network return water is heated by the first heat exchange device and the first heating device, and the heat network supply water stored in the first storage part of the heat storage device is delivered to the heating network system; When the actual water supply temperature is still lower than the preset heating network water supply temperature after the heat storage device is put into operation, the supplementary steam pipeline, the heat storage device, the first heat exchange device and the first heating device are put into operation to increase the temperature of the heating network return water.

11. The method for selecting a heat and power cogeneration energy cascade heating module according to claim 9, characterized in that: The method of selecting the first heat exchange device and / or the first heating device and / or the second heating device or the second heat exchange device to operate to increase the temperature of the heat network return water according to the actually required heating period includes: When the heating period is in a cold period, the first heat exchange device and the first heating device are selected to work to increase the temperature of the heat network return water; When the heating period is at the beginning or end of a cold period, the first heat exchange device or the second heating device or the second heat exchange device is selected to start working to heat the return water of the heating network.

12. The method for selecting a heat and power cogeneration energy cascade heating module according to claim 9, characterized in that: The matching method further comprises: The number of high back pressure coal-fired generating units and cylinder cutting transformation coal-fired generating units participating in the heating network return water of the heating network system is selected according to the temperature and flow rate of the heating network return water of the heating network system.

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