Heating systems and peak-shaving energy storage subsystems that utilize low-grade steam and condensate.

Abstract

This utility model belongs to the technical field of heating systems in the combined heat and power (CHP) industry, specifically relating to a heating system for the reuse of low-grade steam and condensate. The system includes: an energy supply unit and a peak-shaving energy storage unit. The energy supply unit includes: a boiler; a steam turbine, whose inlet is connected to the boiler's steam outlet and whose outlet is connected to the heat user's pipeline network; and a regenerating device, whose inlet is connected to the steam turbine's exhaust outlet and whose outlet is connected to the boiler's feedwater inlet. The peak-shaving energy storage unit includes: a steam-electric dual-drive feedwater pump, whose steam inlet is connected to the steam turbine's extraction pipe; a surface heater, whose makeup water inlet is connected to a makeup water pipeline, and whose steam inlet is connected to the steam turbine's exhaust outlet; and an energy storage hot water tank, connected to the surface heater's makeup water outlet, and whose outlet is connected to the regenerating device's makeup water inlet.

Description

Technical Field

[0001] This utility model belongs to the technical field of heating systems in the cogeneration industry, and particularly relates to a heating system for the reuse of low-grade steam and condensate, and its peak-shaving energy storage subsystem. Background Technology

[0002] In the field of combined heat and power (CHP), steam grade is classified according to its thermodynamic parameters: high-grade steam generally refers to steam with a pressure ≥1.0 MPa and a temperature ≥300°C, possessing a high sludge value; low-grade steam generally refers to steam with a pressure ≤0.5 MPa and a temperature ≤150°C, possessing a low sludge value. Conventional CHP plants utilize high-grade heating steam to heat the feedwater in the thermal system, but significant sludge loss occurs (i.e., high-grade steam is downgraded and wasted), leading to low energy efficiency. Although some CHP plants use high-grade heating steam to drive feedwater pumps and utilize the low-grade steam discharged from the pumps to heat the feedwater, avoiding the waste of high-grade steam sludge, a drawback remains: it cannot supplement heating capacity during peak heating periods to balance peak-valley differences.

[0003] Therefore, how to avoid the waste of high-grade steam and solve the problem that the heating system cannot balance the peak and valley differences in heating is a technical problem that urgently needs to be solved by those skilled in the art.

[0004] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Utility Model Content

[0005] This disclosure provides at least one heating system for the reuse of low-grade steam and hydrophobic condensate, and its peak-shaving energy storage subsystem.

[0006] In a first aspect, embodiments of this disclosure provide a heating system for the reuse of low-grade steam and hydrophobic condensate, comprising: an energy supply unit and a peak-shaving energy storage unit;

[0007] The power supply unit includes:

[0008] boiler;

[0009] The steam turbine has its steam inlet connected to the steam outlet of the boiler and its steam outlet connected to the heat user's pipeline network.

[0010] The regenerative equipment has its inlet connected to the exhaust port of the steam turbine and its outlet connected to the feedwater inlet of the boiler.

[0011] The peak-shaving energy storage unit includes:

[0012] The steam-electric dual-drive feedwater pump has its steam inlet connected to the steam extraction pipe of the steam turbine.

[0013] A surface heater, wherein its water inlet is connected to a water supply pipe, and the steam inlet of the surface heater is connected to the exhaust outlet of the steam turbine;

[0014] The energy storage hot water tank is connected to the water supply outlet of the surface heater, and the water outlet pipe of the energy storage hot water tank is connected to the water supply inlet of the heat recovery equipment.

[0015] In one alternative embodiment, the steam-electric dual-drive feedwater pump includes a steam turbine and an electric motor with dual input shafts.

[0016] When the energy supply unit is in a heating off-peak period, it uses heating steam to drive the feedwater pump and feeds power to the plant power grid through the feedwater pump motor.

[0017] When the energy supply unit is in peak heating season, the water pump is driven by plant power and a small amount of cooling steam is introduced to maintain operation.

[0018] In one optional embodiment, the surface heater is provided with a heat exchange tube bundle, the inlet end of which is connected to a water supply pipe and the outlet end of which is connected to an energy storage hot water tank.

[0019] In one optional embodiment, the bottom of the surface heater is provided with a hydrophobic recovery chamber, which is connected to the energy storage hot water tank through a hydrophobic pipe.

[0020] In one optional embodiment, the energy storage hot water tank is further provided with a steam inlet pipe, which is connected to the steam extraction pipe of the steam turbine.

[0021] Secondly, this disclosure also provides a peak-shaving energy storage subsystem, including: a steam-electric dual-drive feedwater pump, a surface heater, and an energy storage hot water tank;

[0022] The steam inlet of the dual-drive steam-electric feedwater pump is connected to an external steam turbine via an extraction pipe.

[0023] The surface heater has a water inlet connected to a water supply pipe and a steam inlet connected to the exhaust outlet of the steam turbine.

[0024] The energy storage hot water tank is connected to the water supply outlet of the surface heater, and the water outlet pipe of the energy storage hot water tank is connected to the water supply inlet of the heat recovery equipment.

[0025] In one alternative embodiment, the steam-electric dual-drive feedwater pump includes a steam turbine and an electric motor with dual input shafts.

[0026] When the heating system is in a low-heat period, the heating steam is used to drive the feedwater pump, and the feedwater pump motor feeds power to the plant power grid.

[0027] When the heating system is in peak heating season, the feedwater pump is driven by the plant's auxiliary power and a small amount of cooling steam is introduced to maintain operation.

[0028] In one optional embodiment, the surface heater is provided with a heat exchange tube bundle, the inlet end of which is connected to a water supply pipe and the outlet end of which is connected to an energy storage hot water tank.

[0029] In one optional embodiment, the bottom of the surface heater is provided with a hydrophobic recovery chamber, which is connected to the energy storage hot water tank through a hydrophobic pipe.

[0030] In one optional embodiment, the energy storage hot water tank is further provided with a steam inlet pipe, which is connected to the steam extraction pipe of the steam turbine.

[0031] The beneficial effects of this invention are as follows: When the heating load is low, the excess high-grade steam used in this low-grade steam and condensate reuse heating system drives a dual-drive steam-electric feedwater pump. The pump's motor feeds power to the plant's power grid, reducing the plant's power consumption. Meanwhile, the low-grade steam discharged from the dual-drive feedwater pump is input into a surface heater to heat the makeup water inside, thus reusing the low-grade steam. The heated makeup water in the surface heater is then fed into an energy storage tank for hot water energy storage. When the heating load is high, the dual-drive steam-electric feedwater pump is driven by plant power, reducing self-consumption of steam. Simultaneously, hot water is supplied to the regenerative equipment of the energy supply unit through the energy storage tank to increase heating capacity, thereby achieving peak shaving and valley filling in the heating load.

[0032] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and drawings.

[0033] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1This is a schematic diagram of a heating system and its peak-shaving energy storage subsystem that utilizes low-grade steam and hydrophobic condensate, provided as embodiments of this disclosure.

[0036] In the picture:

[0037] 100. Energy supply unit; 110. Boiler; 120. Steam turbine; 121. Steam extraction pipe; 130. Regenerative equipment; 200. Peak-shaving energy storage unit; 210. Steam-electric dual-drive feedwater pump; 220. Surface heater; 221. Heat exchange tube bundle; 222. Drainage recovery chamber; 223. Drainage pipe; 230. Energy storage hot water tank; 231. Steam inlet pipe; 232. Water outlet pipe; 300. Makeup water pipe; 400. Heat user network. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] In this document, when it is mentioned that a first component is located on a second component, this can mean that the first component can be directly formed on the second component, or that a third component can be inserted between the first and second components. Furthermore, in the accompanying drawings, the thickness of the components may be exaggerated or reduced for the purpose of effectively describing the technical content.

[0040] In this document, when an element or layer is referred to as “located,” “joined to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly located, joined, connected, attached to, or coupled to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on another element or layer,” “directly joined to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items.

[0041] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0042] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0043] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0044] Research has revealed the following drawbacks of existing technologies: Conventional thermal power plants utilize high-grade steam to heat the water supply to the thermal system, but this incurs losses and is uneconomical. Some thermal power plants also use steam to drive feedwater pumps, and then use exhaust steam to heat the water supply to the thermal system, reducing plant power consumption and improving economic efficiency, but this cannot balance the peak and off-peak heating differences.

[0045] Based on the above research, this disclosure provides a heating system that utilizes low-grade steam and hydrophobic residue. By using a steam-electric dual-drive feedwater pump with steam-electric coupling, during periods of low gas supply, the feedwater pump motor feeds power to the plant power grid while storing hot water in an energy storage tank. During periods of high gas supply, the energy storage tank replenishes hot water to the power supply unit, reducing self-consumption of steam and increasing heating capacity, thereby achieving peak shaving and valley filling in the heating supply.

[0046] The shortcomings of the above solutions are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed in this disclosure should be considered as the inventor's contribution to this disclosure.

[0047] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] The following detailed description, with reference to the accompanying drawings, describes some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0049] See Figure 1 This disclosure provides a heating system for the reuse of low-grade steam and condensate, comprising: an energy supply unit 100 and a peak-shaving energy storage unit 200. The energy supply unit 100 includes: a boiler 110, a steam turbine 120, and a regenerator 130. The steam inlet of the steam turbine 120 is connected to the steam outlet of the boiler 110, and the steam outlet is connected to the heat user pipeline network 400. The inlet of the regenerator 130 is connected to the exhaust port of the steam turbine 120, and the outlet is connected to the feedwater inlet of the boiler 110. The steam generated by the boiler 110 is distributed to heat users via the steam turbine 120. During periods of low steam supply, the remaining steam from the steam turbine 120 is transported to the regenerator 130, which then returns the steam to the boiler 110 for recycling.

[0050] See also Figure 1The peak-shaving energy storage unit 200 includes: a steam-electric dual-drive feedwater pump 210, whose steam inlet is connected to the extraction pipe 121 of the steam turbine 120. During periods of low gas supply, the extraction pipe 121 transports excess high-grade steam to the steam-electric dual-drive feedwater pump 210, using the feedwater pump motor to feed power to the plant power grid, thereby reducing the plant power consumption rate. A surface heater 220, whose makeup water inlet is connected to the makeup water pipe 300, allows water to be supplied to the surface heater 220. The steam inlet of the surface heater 220 is connected to the exhaust outlet of the steam-electric dual-drive feedwater pump 210. The low-grade steam discharged by the steam-electric dual-drive feedwater pump 210 can fully exchange heat with the makeup water in the surface heater 220, causing the makeup water to heat up and become hot water. An energy storage hot water tank 230 is connected to the makeup water outlet of the surface heater 220, and the outlet pipe 232 of the energy storage hot water tank 230 is connected to the makeup water inlet of the regenerator 130. During peak heating periods, the hot water in the energy storage tank 230 is transferred to the regeneration equipment 130 for recycling by the boiler 110. Since the hot water supplied directly by the energy storage tank 230 does not require further steam heating, the self-consumption of steam can be reduced, increasing the heating capacity of the energy supply unit 100, thereby achieving the effect of peak shaving and valley filling in the heating supply.

[0051] See also Figure 1 In some embodiments, the steam-electric dual-drive feedwater pump 210 includes a steam turbine and an electric motor with dual input shafts. When the power supply unit 100 is in a low heating period, the feedwater pump is driven by heating steam and fed into the plant power grid through the feedwater pump motor to save plant power and improve economic efficiency. When the power supply unit 100 is in a high heating period, the feedwater pump is driven by plant power and only a small amount of cooling steam is introduced to maintain operation, reducing steam consumption.

[0052] As an optional implementation, a steam regulating valve (not labeled in the figure) is installed on the extraction steam pipe 121 to dynamically allocate steam flow according to the heating load: when the heating load is lower than 30% of the design value, the regulating valve opening is ≥80%, and steam is preferentially supplied to the steam-electric dual-drive feedwater pump 210; when the heating load is higher than 90% of the design value, the regulating valve opening is ≤20%, limiting the extraction steam volume to ensure the stability of the user's pipeline network pressure 400.

[0053] See also Figure 1 In some embodiments, the surface heater 220 is equipped with a heat exchange tube bundle 221. The inlet end of the heat exchange tube bundle 221 is connected to the water supply pipe 300, and the outlet end is connected to the energy storage hot water tank 230. The low-grade steam discharged from the steam-electric dual-drive feedwater pump 210 enters the surface heater 220 and exchanges heat with the water supply inside the heat exchange tube bundle 221, thereby heating the water to become hot water.

[0054] See also Figure 1In some embodiments, the surface heater 220 has a condensate recovery chamber 222 at its bottom, which is connected to the energy storage hot water tank 230 via a condensate pipe 223. The low-grade steam discharged from the steam-electric dual-drive feedwater pump 210 exchanges heat with the makeup water in the heat exchange tube bundle 221 and then condenses into condensate. The condensate and makeup water are respectively fed into the energy storage hot water tank 230 through the water supply pipe and the makeup water pipe 300, thus realizing the reuse of the condensate.

[0055] See also Figure 1 In some embodiments, the energy storage hot water tank 230 is also provided with a steam inlet pipe 231, which is connected to the extraction pipe 121 of the steam turbine 120. When the heating unit is in a low-heat period, some excess steam can be input into the energy storage hot water tank 230 to maintain the water temperature of the energy storage hot water tank 230.

[0056] See Figure 1 Some embodiments also provide a peak-shaving energy storage subsystem, including: a steam-electric dual-drive feedwater pump 210, a surface heater 220, and an energy storage hot water tank 230; the steam inlet of the steam-electric dual-drive feedwater pump 210 is connected to an external steam turbine 120 through an extraction pipe 121; the water inlet of the surface heater 220 is connected to a water supply pipe 300, and its steam inlet is connected to the exhaust outlet of the steam-electric dual-drive feedwater pump 210; the energy storage hot water tank 230 is connected to the water supply outlet of the surface heater 220, and the water outlet pipe 232 of the energy storage hot water tank 230 is connected to the water supply inlet of the regenerator 130.

[0057] In summary, this low-grade steam and condensate reuse heating system, when the heating load is low, uses excess high-grade steam to drive the steam-electric dual-drive feedwater pump 210. The pump's motor feeds power to the plant's power grid, reducing the plant's power consumption. Meanwhile, the low-grade steam discharged from the steam-electric dual-drive feedwater pump 210 is input into the surface heater 220 to heat the makeup water within it, thus reusing the low-grade steam. The heated makeup water in the surface heater 220 is then fed into the energy storage hot water tank 230 for hot water storage. When the heating load is high, the steam-electric dual-drive feedwater pump 210 is driven by plant power, reducing its own steam consumption. Simultaneously, the energy storage hot water tank 230 replenishes hot water to the regenerator 130 of the energy supply unit 100, increasing the heating capacity and thus achieving peak shaving and valley filling in the heating load.

[0058] In the description of the embodiments of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0059] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as the second element, component, region, layer, or segment.

[0060] Spatially relative terms, such as “inside,” “outside,” “below,” “below,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is flipped, an element described as “below” or “below” other elements or features would be oriented as “above” other elements or features. Thus, the example term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0061] In the above discussion, unless otherwise stated, when used to describe numerical values, the terms “about,” “approximately,” “basically,” etc., indicate a change of + / - 10% in that value.

[0062] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A heating system with low-grade steam and drain water reuse, characterized in that, include: Energy supply unit (100) and peak-shaving energy storage unit (200); The power supply unit (100) includes: Boiler (110); The steam turbine (120) has its steam inlet connected to the steam outlet of the boiler (110) and its steam outlet connected to the heat user network (400). The regenerator (130) has its inlet connected to the exhaust port of the steam turbine (120) and its outlet connected to the feedwater inlet of the boiler (110); The peak-shaving energy storage unit (200) includes: A steam-electric dual-drive feedwater pump (210) has its steam inlet connected to the extraction pipe (121) of the steam turbine (120). A surface heater (220) has its water inlet connected to a water supply pipe (300), and the steam inlet of the surface heater (220) is connected to the exhaust outlet of a steam-electric dual-drive feed water pump (210). The energy storage hot water tank (230) is connected to the water supply outlet of the surface heater (220), and the water outlet pipe (232) of the energy storage hot water tank (230) is connected to the water supply inlet of the heat recovery device (130).

2. The heating system for reusing low-grade steam and hydrophobic condensate as described in claim 1, characterized in that, The steam-electric dual-drive feedwater pump (210) includes a steam turbine and an electric motor with dual input shafts; When the power supply unit (100) is in a low heating period, it uses heating steam to drive the feed water pump and feeds power to the plant power grid through the feed water pump motor. When the power supply unit (100) is at its peak heating period, the water pump is driven by the plant's electricity and a small amount of cooling steam is introduced to maintain operation.

3. A heating system for the reuse of low-grade steam and hydrophobic condensate as described in claim 1, characterized in that, The surface heater (220) is equipped with a heat exchange tube bundle (221). The inlet end of the heat exchange tube bundle (221) is connected to the water supply pipe (300), and the outlet end is connected to the energy storage hot water tank (230).

4. A heating system for the reuse of low-grade steam and hydrophobic condensate as described in claim 1, characterized in that, The bottom of the surface heater (220) is provided with a hydrophobic recovery chamber (222), which is connected to the energy storage hot water tank (230) through a hydrophobic pipe (223).

5. A heating system for the reuse of low-grade steam and hydrophobic condensate as described in claim 1, characterized in that, The energy storage hot water tank (230) is also equipped with a steam inlet pipe (231), which is connected to the extraction pipe (121) of the steam turbine (120).

6. A peak-shaving energy storage subsystem for a heating system, characterized in that, include: A steam-electric dual-drive water pump (210), a surface heater (220), and an energy storage hot water tank (230); The steam inlet of the dual-drive steam-electric feedwater pump (210) is connected to an external steam turbine (120) via a steam extraction pipe (121); The surface heater (220) has its water inlet connected to the water supply pipe (300), and its steam inlet connected to the exhaust outlet of the steam-electric dual-drive feed water pump (210). The energy storage hot water tank (230) is connected to the water supply outlet of the surface heater (220), and the water outlet pipe (232) of the energy storage hot water tank (230) is connected to the water supply inlet of the heat recovery device (130).

7. The peak-shaving energy storage subsystem as described in claim 6, characterized in that, The steam-electric dual-drive feedwater pump (210) includes a steam turbine and an electric motor with dual input shafts; When the heating system is in a low-heat period, the heating steam is used to drive the feedwater pump, and the feedwater pump motor feeds power to the plant power grid. When the heating system is in peak heating season, the feedwater pump is driven by the plant's auxiliary power and a small amount of cooling steam is introduced to maintain operation.

8. The peak-shaving energy storage subsystem as described in claim 6, characterized in that, The surface heater (220) is equipped with a heat exchange tube bundle (221). The inlet end of the heat exchange tube bundle (221) is connected to the water supply pipe (300), and the outlet end is connected to the energy storage hot water tank (230).

9. The peak-shaving energy storage subsystem as described in claim 6, characterized in that, The bottom of the surface heater (220) is provided with a hydrophobic recovery chamber (222), which is connected to the energy storage hot water tank (230) through a hydrophobic pipe (223).

10. The peak-shaving energy storage subsystem as described in claim 6, characterized in that, The energy storage hot water tank (230) is also equipped with a steam inlet pipe (231), which is connected to the extraction pipe (121) of the steam turbine (120).

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