A heating system for both heating and steam supply

Abstract

The utility model belongs to the technical field of heat supply system provides a kind of heat system that considers both heating and steam supply, comprising: front end flash tank, rear end flash tank, first valve, second valve, third valve, fourth valve, fifth valve, waste heat recovery unit, sharp peak heater, water supply opening, several steam compressors, large temperature difference heat exchange unit, gas holder, primary network water supply opening, primary network backwater opening, secondary network water supply opening and secondary network backwater opening;Front end flash tank and rear end flash tank all include: several series flash tank.The utility model is through being provided with front end flash tank and large temperature difference heat exchange unit, has realized steam and hot water simultaneously generation, it is favorable to energy gradient utilization;Through being provided with fifth valve and waste heat recovery unit, the matching of system end load and the recycling of plant waste heat are realized, so that system regulation is more flexible and convenient, and energy efficiency is higher.

Description

Technical Field

[0001] This utility model relates to the field of heating system technology, and in particular to a thermal system that combines heating and steam supply. Background Technology

[0002] The first type of absorption heat pump is a heat-enhancing type heat pump. It utilizes a small amount of high-temperature heat to raise the thermal energy of a low-temperature heat source to a medium temperature, generating a large amount of useful medium-temperature heat energy. This improves the efficiency of heat energy utilization and has the dual function of saving energy and protecting the environment. The first type of absorption heat pump combined with a plate heat exchanger forms a large temperature difference heat exchange unit, which can significantly increase the temperature difference between the primary network supply and return water. The primary network operates with a large temperature difference and low flow rate, enabling long-distance transmission over the primary network, with a transmission radius exceeding 200 km. With the large-scale application of large temperature difference heat exchange units, the technology for long-distance hot water transmission has been verified by engineering projects and recognized by the industry. However, the heating network is only used during the heating season, resulting in low utilization. Industrial steam is an important energy source in industrial production, used to drive machinery, heat materials, clean components, generate electricity, and refrigerate. Current steam sources are mainly direct supply from thermal power plants and steam produced by self-owned coal-fired and gas-fired boilers. Direct supply from thermal power plants has limited transmission distance and significant heat loss along the way. Coal-fired and gas-fired boilers consume fossil fuels, which does not comply with carbon reduction policies and causes environmental pollution. For existing technologies, utilizing hot water pipe networks to generate steam, combining long-distance hot water transmission with steam generation, can improve the utilization rate of existing heating networks and reduce or even eliminate self-owned boilers used for steam production. Deploying this system on the user side allows for precise steam supply, producing steam as needed. Compared to direct steam supply, this significantly reduces heat loss in the pipe network, extends the steam supply radius to 200km, increases pipe network utilization to 100%, and shortens the infrastructure investment payback period. An existing patent for a large temperature difference long-distance steam power supply system (CN202310207335.X) includes an absorption heat exchanger unit, a condenser, a throttling mechanism, and a steam generator. The condenser and the steam generator are connected in a loop via pipes, and the steam generator is connected to a steam outlet. This patent combines long-distance hot water transmission with a steam generation system, utilizing existing long-distance heating pipelines to produce steam. This results in low initial investment and improved pipeline utilization. An existing patent, an absorption-type large temperature difference steam heat pump unit (CN202320401206.X), combines long-distance hot water transmission, centralized heating, and industrial steam systems by configuring an absorption-type large temperature difference heat exchange unit, a steam generation unit, and a terminal heat exchange unit. This allows pipelines and equipment originally designed solely for heating to be used year-round, improving utilization and effectively reducing steam costs for industrial enterprises.

[0003] Based on existing technologies, coal-fired and gas-fired boilers consume large amounts of fossil fuels, causing significant environmental pollution. Direct steam supply from thermal power plants has a heating radius of 30 km or less, with a pressure drop of 0.04 to 0.05 MPa and a temperature drop of 3 to 6°C per km, resulting in substantial heat loss and high initial investment. In contrast, long-distance hot water transmission, which generates steam at the end of the pipeline, has a heating radius of 200 km or more, with a temperature drop of less than 0.05°C per km. Furthermore, hot water pipelines have lower pressure resistance, simpler design, easier control, and lower initial investment compared to steam pipelines. The aforementioned large temperature difference long-distance steam energy supply system does not combine heating and steam supply, so it cannot provide heating during the heating season, and the system is relatively complex and difficult to modify. The aforementioned absorption large temperature difference steam heat pump unit can provide heating and steam simultaneously by transporting hot water to the terminal, but it does not fully utilize the temperature potential energy of the primary network. The high-temperature hot water from the primary network first flows into the absorption large temperature difference heat exchanger unit to prepare medium-temperature hot water, and then the medium-temperature hot water is flashed to produce industrial steam. Due to the nature of the first type of absorption heat pump, the medium-temperature water temperature is generally below 70°C, the hot water temperature used for flashing is low, the flashing rate is low, and the system power consumption increases. Utility Model Content

[0004] To overcome the shortcomings of existing technologies, the purpose of this utility model is to provide a thermal system that combines heating and steam supply. By setting up a front-end flash tank and a large temperature difference heat exchanger, the system utilizes the heat energy of the primary network in stages to simultaneously generate industrial steam and heating hot water. By setting up a fifth valve and a waste heat recovery unit, the system can match the load at the end of the system and recover and utilize the waste heat in the plant, making the system adjustment more flexible and convenient and more energy efficient.

[0005] To achieve the above objectives, this utility model provides the following solution:

[0006] A thermal system that combines heating and steam supply includes: a front-end flash tank, a rear-end flash tank, a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a waste heat recovery unit, a peak heater, a water inlet, several steam compressors, a large temperature difference heat exchanger unit, a gas storage tank, a primary network water supply inlet, a primary network water return inlet, a secondary network water supply inlet, and a secondary network water return inlet; both the front-end flash tank and the rear-end flash tank include several flash tanks connected in series.

[0007] The primary network water supply inlet is connected to the inlet of the fifth valve; the outlet of the fifth valve is connected to the inlet of the front flash tank; each steam outlet of the front flash tank is connected to the inlet of a steam compressor; the terminal output of the front flash tank is connected to the inlets of the first valve and the third valve respectively; the inlet and outlet of the primary network side of the large temperature difference heat exchanger are connected to the outlet of the first valve and the inlet of the second valve respectively; the outlet and inlet of the secondary network side of the large temperature difference heat exchanger are connected to the secondary network water supply inlet and the secondary network return inlet respectively; the outlet of the third valve is connected to the downstream... The inlet of the end flash tank is connected; each steam outlet of the end flash tank is connected to the inlet of a steam compressor; the end output of the end flash tank is connected to the inlet of the fourth valve; the primary network return port is connected to the outlet of the second valve, the outlet of the fourth valve, and the water supply port; the inlet of the waste heat recovery unit is connected to the primary network return port; the inlet and outlet of the peak heater are respectively connected to the outlet of the waste heat recovery unit and the primary network water supply port; the outlets of all the steam compressors are connected to the inlet of the gas storage tank; the outlet of the gas storage tank is connected to an external steam output pipeline.

[0008] Both the front-end flash tank and the rear-end flash tank are used for multi-stage flash evaporation to obtain low-pressure steam; the waste heat recovery unit is used to heat the primary network return water supplied through the water inlet by the second valve and the fourth valve using industrial waste heat; the peak heater is used to reheat the heated primary network return water to the target temperature; the steam compressors are used to pressurize the low-pressure steam and deliver the resulting high-pressure steam to the gas storage tank; the large temperature difference heat exchanger unit is used to heat the low-temperature water input through the secondary network return water inlet using the primary network water supplied by the front-end flash tank to obtain medium-temperature water, and deliver the medium-temperature water to the target hot water user through the secondary network supply outlet; the gas storage tank is used to deliver high-temperature and high-pressure steam to the target steam user through the external steam output pipeline.

[0009] The present invention discloses the following technical effects:

[0010] This utility model provides a thermal system that combines heating and steam supply. By setting up a front-end flash tank and a large temperature difference heat exchanger, it solves the problem of low energy utilization in traditional systems and realizes the simultaneous generation of industrial steam and heating hot water as well as the gradient utilization of energy. By setting up a fifth valve and a waste heat recovery unit, it solves the problems of complex control and low energy efficiency in traditional systems and realizes the matching of the system's terminal load and the recovery and utilization of waste heat in the plant. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A structural diagram of a thermal system that combines heating and steam supply is provided for an embodiment of this utility model;

[0013] Figure 2 A diagram showing the relationship between the primary network flow ratio and the heating load ratio is provided for embodiments of this utility model.

[0014] Figure 3 A diagram showing the relationship between the primary network bypass flow ratio and the heating load ratio is provided for an embodiment of this utility model.

[0015] Explanation of reference numerals in the attached figures:

[0016] 1-Large temperature difference heat exchanger unit, 2-Waste heat recovery unit, 3-Peak heater, 4-Primary network water supply port, 5-Primary network water return port, 6-Front-end flash tank, 7-Rear-end flash tank, 8-Air storage tank, 9-Secondary network water supply port, 10-Secondary network water return port, 11-First valve, 12-Second valve, 13-Third valve, 14-Fourth valve, 15-Fifth valve, 16-Water inlet, P-Steam compressor. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] The purpose of this utility model is to provide a thermal system that combines heating and steam supply. By setting up a front-end flash tank and a large temperature difference heat exchanger, the system utilizes the heat energy of the primary network in stages to simultaneously generate industrial steam and heating hot water. By setting up a fifth valve and a waste heat recovery unit, the system can match the load at the end of the system and recover and utilize the waste heat in the plant, making the system adjustment more flexible and convenient and more energy efficient.

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1A structural diagram of a thermal system that combines heating and steam supply, as provided in the embodiments of this utility model, is shown below. Figure 1 As shown, this utility model provides a thermal system that combines heating and steam supply, including: a front flash tank 6, a rear flash tank 7, a first valve 11, a second valve 12, a third valve 13, a fourth valve 14, a fifth valve 15, a waste heat recovery unit 2, a peak heater 3, a water inlet 16, several steam compressors P, a large temperature difference heat exchanger unit 1, a gas storage tank 8, a primary network water supply inlet 4, a primary network water return inlet 5, a secondary network water supply inlet 9, and a secondary network water return inlet 10; both the front flash tank 6 and the rear flash tank 7 include several flash tanks connected in series;

[0021] The primary network water supply port 4 is connected to the inlet of the fifth valve 15; the outlet of the fifth valve 15 is connected to the inlet of the front flash tank 6; each steam outlet of the front flash tank 6 is connected to the inlet of a steam compressor P; the terminal output of the front flash tank 6 is connected to the inlets of the first valve 11 and the third valve 13 respectively; the inlet and outlet of the primary network side of the large temperature difference heat exchanger unit 1 are connected to the outlet of the first valve 11 and the inlet of the second valve 12 respectively; the outlet and inlet of the secondary network side of the large temperature difference heat exchanger unit 1 are connected to the secondary network water supply port 9 and the secondary network return port 10 respectively; the outlet of the third valve 13 is connected to the downstream... The inlet of the end flash tank 7 is connected; each steam outlet of the rear flash tank 7 is connected to the inlet of a steam compressor P; the end output of the rear flash tank 7 is connected to the inlet of the fourth valve 14; the primary network return port 5 is connected to the outlet of the second valve 12, the outlet of the fourth valve 14, and the water supply port 16; the inlet of the waste heat recovery unit 2 is connected to the primary network return port 5; the inlet and outlet of the peak heater 3 are connected to the outlet of the waste heat recovery unit 2 and the primary network water supply port 4, respectively; the outlets of all steam compressors P are connected to the inlet of the gas storage tank 8; the outlet of the gas storage tank 8 is connected to the external steam output pipeline.

[0022] Both the front-end flash tank 6 and the rear-end flash tank 7 are used for multi-stage flash evaporation to obtain low-pressure steam; the waste heat recovery unit 2 is used to heat the primary network return water supplied through the water inlet 16 via the second valve 12 and the fourth valve 14 using industrial waste heat; the peak heater 3 is used to reheat the heated primary network return water to the target temperature; the steam compressor P is used to pressurize the low-pressure steam and deliver the resulting high-pressure steam to the gas storage tank 8; the large temperature difference heat exchanger unit 1 is used to heat the low-temperature water input at the secondary network return water inlet 10 using the primary network water supplied by the front-end flash tank 6 to obtain medium-temperature water, and deliver the medium-temperature water to the target hot water user through the secondary network supply outlet 9; the gas storage tank 8 is used to deliver high-temperature and high-pressure steam to the target steam user through an external steam output pipeline.

[0023] Specifically, during the severe cold period, valves 11 and 12 are open, while valves 13 and 14 are closed. The primary network water supply passes through the front-end flash tank 6, where it is flashed to produce low-pressure steam. Simultaneously, the hot water temperature decreases. This cooled primary network hot water then flows into the large temperature difference heat exchanger unit 1 to exchange heat with the secondary network to produce heating hot water. During the non-severe cold period, the heating load decreases. The load on the large temperature difference heat exchanger unit 1 can be reduced by bypassing the primary network water. At this time, valves 11 and 12 are partially closed, while valves 13 and 14 are partially open. This allows the primary network water to bypass the large temperature difference heat exchanger unit 1 before flowing into the latter, where flash tank 7 can be set to multiple stages, flashing the hot water to below 30°C. The total steam supply of the system increases at this time, and the system steam output can be kept constant by adjusting valve 15 to reduce the primary network flow rate. During the non-heating season, there is no heating load at the end of the heating cycle, and the large temperature difference heat exchanger unit 1 is shut down. The primary network water supply, after n stages of flashing, returns to the plant at a temperature below 30°C. At this time, the first valve 11 and the second valve 12 are closed, while the third valve 13 and the fourth valve 14 are open.

[0024] Preferably, the present invention will be further described below through specific embodiments:

[0025] The system's design operating condition is taken as the system's operating condition during the severe cold period. Under the design operating condition, valves 11, 12, and 15 are fully open, while valves 13 and 14 are fully closed. The large temperature difference heat exchanger unit 1 and the front-end flash tank 6 operate at full load, while the rear-end flash tank 7 is shut down.

[0026] In non-design operating conditions, heating requires only partial load, and the industrial steam load is relatively constant. At this time, valves 11 and 12 are partially closed, while valves 13 and 14 are partially open, bypassing the primary network water to reduce the heating load. To ensure a constant total system steam output, valve 15 is partially closed to reduce the primary network water flow.

[0027] When using flow regulation, under specific temperature and load conditions, in order to meet heating load fluctuations while maintaining a constant steam volume, the primary network flow regulation curve is as follows: Figure 2 As shown, the primary network flow rate and the bypass flow rate before the large temperature difference heat exchanger unit 1 are as follows: Figure 3 As shown.

[0028] refer to Figure 2 During the coldest period, when heating is at full load, the primary network flow rate is 100%. As the heating load decreases, the primary network flow rate also decreases. During the non-heating season, when the heating load is zero, the primary network only needs to operate at 38% of its flow rate. The primary network flow rate ratio and the heating load ratio have an approximately linear relationship.

[0029] refer to Figure 3During the coldest period, when heating is at full load, the primary network flow bypass ratio is 0%. As the heating load decreases, the primary network flow bypass ratio increases, reaching 100% when the heating load is 0 during the non-heating season.

[0030] Alternatively, in addition to quantity regulation, the primary network can also employ quality regulation or quality-flow regulation. The above analysis is merely an example.

[0031] Preferably, this utility model employs the aforementioned thermal system that combines heating and steam supply, fully utilizing the temperature potential energy of the primary network. High-temperature hot water is first used for flash evaporation to prepare industrial steam, and after the temperature is reduced, it enters the large temperature difference heat exchanger unit 1 to prepare heating hot water. The high steam temperature and low heating hot water temperature are beneficial for the cascade utilization of energy in the primary network. Applied to a long-distance heat network with a large temperature difference, existing long-distance heating pipelines can be used to prepare industrial steam, and steam production can be achieved at the terminal with simple modifications, increasing the utilization rate of the heat network to 100%. It is easy to operate, with the primary network operating at a large temperature difference and a small flow rate, resulting in minimal heat loss along the hot water path. The heating radius of the long-distance pipeline network is greater than or equal to 200 km, and steam supply is no longer limited by distance. The low-temperature return water from the primary network is returned to the heat source plant to recover waste heat. The terminal heating load and steam load can be matched through simple primary network flow regulation, further improving system energy efficiency. It has advantages such as low initial pipeline investment, steam production on demand, and flexible and reliable operation condition adjustment.

[0032] The beneficial effects of this utility model are as follows:

[0033] (1) This utility model provides a thermal system that combines heating and steam supply, making full use of the temperature potential energy of the primary network. The high-temperature hot water is first used to flash-evaporate industrial steam, and after the temperature is reduced, it enters the large temperature difference heat exchanger unit to produce heating hot water. The high steam temperature and low heating hot water temperature are conducive to the cascade utilization of the primary network energy;

[0034] (2) The thermal system provided by this utility model can make full use of the centralized heating network to meet the heating needs, and can also generate industrial steam at the end after simple modification. It is easy to operate and has a low initial investment.

[0035] (3) Compared with long-distance steam transmission, the thermal system provided by this utility model that combines heating and steam supply has greatly reduced the loss along the way and the transmission distance is extended to more than 200km; compared with steam production by boilers, it achieves zero emissions; and when combined with nuclear power plants, it can achieve zero-carbon steam production.

[0036] (4) The thermal system adopted by this utility model can match the terminal heating load and steam load through simple primary network flow adjustment. After the low temperature return water of the primary network returns to the heat source plant, it continuously recovers the waste heat in the plant. The system load adjustment is flexible and convenient, and the energy efficiency is further improved.

[0037] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0038] This document uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. Furthermore, those skilled in the art will recognize that, based on the ideas of this utility model, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A thermal system that combines heating and steam supply, characterized in that, include: The system includes a front-end flash tank, a rear-end flash tank, a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a waste heat recovery unit, a peak heater, a water inlet, several steam compressors, a large temperature difference heat exchanger unit, a gas storage tank, a primary network water supply inlet, a primary network water return inlet, a secondary network water supply inlet, and a secondary network water return inlet; both the front-end flash tank and the rear-end flash tank include several flash tanks connected in series. The primary network water supply inlet is connected to the inlet of the fifth valve; the outlet of the fifth valve is connected to the inlet of the front flash tank; each steam outlet of the front flash tank is connected to the inlet of a steam compressor; the terminal output of the front flash tank is connected to the inlets of the first valve and the third valve respectively; the inlet and outlet of the primary network side of the large temperature difference heat exchanger are connected to the outlet of the first valve and the inlet of the second valve respectively; the outlet and inlet of the secondary network side of the large temperature difference heat exchanger are connected to the secondary network water supply inlet and the secondary network return inlet respectively; the outlet of the third valve is connected to the downstream... The inlet of the end flash tank is connected; each steam outlet of the end flash tank is connected to the inlet of a steam compressor; the end output of the end flash tank is connected to the inlet of the fourth valve; the primary network return port is connected to the outlet of the second valve, the outlet of the fourth valve, and the water supply port; the inlet of the waste heat recovery unit is connected to the primary network return port; the inlet and outlet of the peak heater are respectively connected to the outlet of the waste heat recovery unit and the primary network water supply port; the outlets of all the steam compressors are connected to the inlet of the gas storage tank; the outlet of the gas storage tank is connected to an external steam output pipeline. Both the front-end flash tank and the rear-end flash tank are used for multi-stage flash evaporation to obtain low-pressure steam; the waste heat recovery unit is used to heat the primary network return water supplied through the water inlet by the second valve and the fourth valve using industrial waste heat; the peak heater is used to reheat the heated primary network return water to the target temperature; the steam compressors are used to pressurize the low-pressure steam and deliver the resulting high-pressure steam to the gas storage tank; the large temperature difference heat exchanger unit is used to heat the low-temperature water input through the secondary network return water inlet using the primary network water supplied by the front-end flash tank to obtain medium-temperature water, and deliver the medium-temperature water to the target hot water user through the secondary network supply outlet; the gas storage tank is used to deliver high-temperature and high-pressure steam to the target steam user through the external steam output pipeline.

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