Heating system

Abstract

The present disclosure relates to a heat supply system, comprising: a steam turbine for providing steam; a condenser in communication with the steam turbine for condensing the steam generated by the steam turbine into condensed water; a heater in communication with the condenser for heating the condensed water; and a heat exchanger in communication with the heater for heating the heated condensed water as a heat exchange medium for heating return water of a heat network. The present disclosure sets the condenser to condense the steam provided by the steam turbine into condensed water, and the condensed water is heated by the heater and then delivered to the heat exchanger as a heat exchange medium to heat the return water of the heat network passing through the heat exchanger. The heated condensed water exchanges heat with the return water of the heat network, and there is no energy difference between water and water. The temperature of the condensed water is lower than that of the steam, which reduces the temperature difference between the condensed water and the return water of the heat network, and reduces the effective energy loss.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of heat supply network, in particular, to a heat supply system. BACKGROUND

[0002] The principle of power generation of a thermal power plant is to generate steam by a boiler first, then send the steam into a steam turbine, the rotation of the steam turbine drives a generator to generate electricity, the exhaust of the steam turbine enters a condenser to condense into water, and the condensed water is sent into the boiler by a condensate pump, thus forming a cycle; the thermal power plant needs to supply heat while generating electricity, and a conventional heat supply system uses steam extraction of a steam turbine to heat heat network water, that is, a hole is opened on a medium-low pressure cylinder communication pipe to heat and supply heat to the outside, a part of steam used for power generation is extracted to supply heat, and high-temperature steam is used to heat heat network water; since there is a large temperature difference and energy level difference in the heat exchange process between the steam and the water, the conventional heat supply system has a large effective energy loss in the steam-water heat exchange process. SUMMARY

[0003] The purpose of the present disclosure is to provide a heat supply system which can reduce effective energy loss in the heat supply process.

[0004] In order to achieve the above-mentioned purpose, the present disclosure provides a heat supply system, comprising: a steam turbine for providing steam; a condenser in communication with the steam turbine for condensing the steam generated by the steam turbine into condensed water; a heater in communication with the condenser for heating the condensed water; and a heat exchanger in communication with the heater for heating heat network return water by using the heated condensed water as a heat exchange medium.

[0005] Optionally, the heater is provided with a plurality of heaters in series to heat the condensed water step by step.

[0006] Optionally, at least two of the heaters are in communication with the heat exchanger through a switching valve.

[0007] Optionally, the heater is configured as a low-pressure heater, the low-pressure heater comprises a heating bin for accommodating a heating medium and a heat exchange pipe for the passage of condensed water, the heat exchange pipe is in communication with the condenser, the heating bin is in communication with the steam turbine to heat the condensed water by using steam, and the heating bins of a plurality of low-pressure heaters are in communication with the steam turbine respectively to heat the condensed water step by step.

[0008] Optionally, the heat supply system further comprises a recovery device in communication with the heating bin to recover the heating medium and the condensed water after heating the condensed water.

[0009] Optionally, the recovery device comprises a drain expansion vessel and a deaerator, the heating bins of a plurality of low-pressure heaters are in communication with the drain expansion vessel, the drain expansion vessel is in communication with the deaerator, and the drain expansion vessel is further used to communicate with a boiler.

[0010] Optionally, the outlet end of the heat exchanger is communicated with the low-pressure heater close to the condenser through a recirculation pump, and the outlet end of the heat exchanger is connected to the heating bin of the low-pressure heater to recover the waste heat of the condensed water.

[0011] Optionally, the recirculation pump is provided with two in parallel.

[0012] Optionally, the heater comprises a first heater, a second heater and a third heater connected in series, and the switching valve comprises a first switching valve and a second switching valve, the first heater is communicated with the condenser, the second heater is communicated with the heat exchanger through the first switching valve, and the third heater is communicated with the heat exchanger through the second switching valve.

[0013] Optionally, the heat exchanger is configured as a plate heat exchanger.

[0014] Through the above technical solution, the steam provided by the steam turbine is condensed into condensed water by the condenser, and the condensed water is heated by the heater and then delivered into the heat exchanger as a heat exchange medium to heat the return water of the heat network passing through the heat exchanger. The condensed water after heating and the return water of the heat network are subjected to water-water heat exchange, and there is no energy difference between water and water. Moreover, the temperature of the condensed water is lower than that of the steam, which reduces the temperature difference between the condensed water and the return water of the heat network and reduces the effective energy loss.

[0015] Other features and advantages of the present disclosure will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following specific embodiments to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0017] Figure 1 is a structural schematic diagram of the heat supply system described in the present disclosure.

[0018] EXPLANATION OF REFERENCE NUMERALS

[0019] 1, steam turbine; 2, condenser; 3, heater; 301, heating bin; 302, heat exchange pipe; 31, first heater; 32, second heater; 33, third heater; 4, heat exchanger; 5, recirculation pump; 6, recovery device; 61, drain expansion vessel; 62, deaerator; 7, switching valve; 71, first switching valve; 72, second switching valve. DETAILED DESCRIPTION

[0020] The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended for illustration and explanation of the present disclosure and are not intended to limit the present disclosure.

[0021] In the present disclosure, "inner, outer" refers to the inner, outer relative to the outline of the component or structure itself, unless otherwise stated. In addition, it should be noted that the terms used, such as "first, second", etc. are used to distinguish one element from another element, and do not have sequentiality and importance. In addition, in the description with reference to the drawings, the same reference signs in different drawings represent the same elements.

[0022] As shown in Figure 1 The present disclosure provides a heating system, comprising: a steam turbine 1 for providing steam; a condenser 2 in communication with the steam turbine 1 for condensing the steam generated by the steam turbine 1 into condensed water, the condenser 2 is a heat exchanger for condensing the exhaust steam of the steam turbine 1 into water, also known as a water recovery device; a heater 3 in communication with the condenser 2 for heating the condensed water; and a heat exchanger 4 in communication with the heater 3 to heat the heated condensed water as a heat exchange medium for the heat return water of the heat network.

[0023] Through the above technical solution, the heating system provided by the present disclosure, by setting the condenser 2 to condense the steam provided by the steam turbine 1 into condensed water, the condensed water is heated by the heater 3 and then delivered to the heat exchanger 4 as a heat exchange medium, and the heat return water of the heat network is heated by the heat exchanger 4. The condensed water and the heat return water of the heat network are water-water heat exchanged, there is no energy difference between water and water, and the temperature of the condensed water is lower than that of the steam, which reduces the temperature difference between the condensed water and the heat return water of the heat network, reduces the effective energy loss, and the condensed water itself has a certain temperature. When the heater 3 heats the condensed water, it will not consume much energy, which is much smaller than the energy loss. Because the power plant itself generates condensed water during power generation, the present disclosure uses the generated condensed water to heat the heating system, which can reduce the energy consumption of the system and also reduce the effective energy loss.

[0024] As an optional embodiment, as shown in Figure 1 The heater 3 is provided with a plurality of heaters in series to heat the condensed water step by step, so that the heating speed is faster, and the temperature of the condensed water can be higher.

[0025] Optionally, at least two heaters 3 are in communication with the heat exchanger 4 through a switching valve 7, because the condensed water in each heater 3 has different temperatures, the switching valve 7 is used to switch the heater 3 that supplies water to the heat exchanger 4 to provide condensed water with different temperatures to the heat exchanger 4. When the unit is under high load, use condensed water with lower temperature as heating source, when the unit is under low load, use condensed water with higher temperature as heating source, according to different unit parameters, switch and use each other, which can improve the economic efficiency of the system.

[0026] As an optional implementation method, such as Figure 1 As shown, heater 3 is a low-pressure heater. Its function is to utilize steam that has done some work in turbine 1, drawing it into the heater to heat the feedwater, increasing the water temperature, reducing the amount of steam discharged from turbine 1 to condenser 2, lowering energy loss, and improving the cycle efficiency of the thermal system. The low-pressure heater includes a heating chamber 301 for containing the heating medium and heat exchange tubes 302 for condensate to pass through. Heat exchange tubes 302 are connected to condenser 2, and heating chamber 301 is connected to turbine 1 to use steam to heat the condensate. Condensate is formed by the condensation of high-temperature steam and already has a high temperature. Heating it with steam then heats the return water for the heating network. The amount of steam used to heat the condensate is far less than the amount of steam used to directly heat the return water for the heating network. Furthermore, the condensate used is condensate generated by the power plant itself. Water is used, so the energy consumption of using condensate to heat the return water of the heating network is much lower than that of directly using steam to heat the return water of the heating network. The heating chambers 301 of multiple low-pressure heaters are connected to the steam turbine 1 to heat the condensate in stages. The reason for setting multiple low-pressure heaters is that when steam heats condensate, it exchanges heat with condensate, and the steam temperature gradually decreases. The condensate can only be heated to a certain temperature and cannot reach the required temperature. It can only enter the next low-temperature heater 3 and be heated again by new high-temperature steam. Multiple low-pressure heaters are connected to the steam turbine 1 to ensure that the steam entering each low-pressure heater is high-temperature steam, so that the condensate in the low-pressure heater can be heated in stages. If multiple low-pressure heaters use the same steam, the steam temperature will decrease after heating the first low-pressure heater, and it will be difficult to heat the condensate with the rising temperature in the next low-pressure heater.

[0027] Optionally, the heating system also includes a recovery device 6 connected to the heating chamber 301 to recover the heating medium and condensate after heating the condensate. Steam releases heat after heating the condensate to form condensate, and the condensate and condensate enter the recovery device 6 for recovery and reuse.

[0028] The recovery device 6 includes a condensate expansion container 61 and a deaerator 62. The heating chambers 301 of multiple low-pressure heaters are all connected to the condensate expansion container 61, which is also connected to the deaerator 62. The condensate expansion container 61 is also connected to the boiler. The condensate expansion container 61 expands and depressurizes pressurized water, separating steam and condensate. The steam is introduced into the deaerator 62 to fully utilize its thermal energy, while the condensate is introduced into the boiler as boiler return water, ensuring the boiler's return water volume. In other words, instead of directly feeding the condensate from the condenser 2 into the boiler, this disclosure utilizes the condensate to supply heat to the heating network before introducing the condensate into the boiler, thus not affecting the boiler's return water and fully utilizing the heat of the condensate.

[0029] Optionally, the outlet of the heat exchanger 4 is communicated with the low-pressure heater near the condenser 2 through a recirculation pump 5, and the outlet of the heat exchanger 4 is connected to the heating bin 301 of the low-pressure heater to recover the waste heat of the condensed water. After the condensed water exchanges heat with the heat network return water, there is still some waste heat. The condensed water is introduced into the heating bin 301 of the low-pressure heater to continue heat release and waste heat recovery, so as to fully utilize the heat. The condensed water after waste heat recovery enters the drain expansion vessel 61. Since the temperature of the condensed water after heat exchange decreases, it can only be introduced into the low-pressure heater near the condenser 2. At this time, the temperature of the condensed water in the low-pressure heater is low. If it is introduced into the low-pressure heater at the rear, not only the heating effect is poor, but also it may even absorb heat in the opposite direction.

[0030] Optionally, two recirculation pumps 5 are provided in parallel, one is used and the other is standby, so as to prevent the system from failing to operate normally after the recirculation pump 5 is damaged.

[0031] Optionally, the heater 3 includes a first heater 31, a second heater 32 and a third heater 33 connected in series, and the switching valve 7 includes a first switching valve 71 and a second switching valve 72. The first heater 31 is communicated with the condenser 2. The second heater 32 is communicated with the heat exchanger 4 through the first switching valve 71. The third heater 33 is communicated with the heat exchanger 4 through the second switching valve 72. The two heaters 3 at the rear are communicated with the heat exchanger 4 through the switching valve 7. The switching valve 7 is provided with two switching valves for controlling the two heaters 3. According to different unit parameters, the two heaters 3 are switched and used, so as to improve the economic efficiency of the system.

[0032] As an optional embodiment, the heat exchanger 4 is configured as a plate heat exchanger 4. The plate heat exchanger 4 is a high-efficiency heat exchanger composed of a series of metal sheets with a certain corrugated shape. Under the same pressure loss, the heat transfer coefficient is 3-5 times higher than that of a tubular heat exchanger, and the occupied area is one-third of that of a tubular heat exchanger. In other embodiments, the heat exchanger 4 can also be configured as a tubular heat exchanger.

[0033] In actual use, part of the steam provided by the steam turbine 1 is condensed into condensed water through the condenser 2 and then enters the first heater 31, the second heater 32 and the third heater 33 for step-by-step heating, and another part of the steam enters the heating bin 301 of the low-pressure heater for heating the condensed water, the heated condensed water enters the heat exchanger 4 for heating the heat network return water, and then the condensed water after heat release and the heating medium after heating the condensed water enter the drain expansion vessel 61, the drain expansion vessel 61 expands the water under pressure into steam and drain, the steam enters the deaerator 62 for deaeration and recovers heat into the next system, and the drain returns to the boiler as boiler return water. The heating system of the present disclosure is suitable for small-area heating. If the heating area is small, the required heating capacity is small, it is not easy to carry out large-scale heat pump heating scheme, and a large amount of condensed water is required for large-scale heating, which is difficult to produce, and if too much condensed water is produced, it is easy to waste, and the boiler cannot use so much return water. For example, the heating area is determined as 300,000 square meters in the short term and 600,000 square meters in the long term, the maximum heating load is 18MW, the heat network circulating water quantity is 300T / H considering the heat network circulating water temperature rise of 50 degrees, the plate heat exchanger 4 heat exchange area is 600m 2 , the single recirculation pump 5 circulating quantity is 300T / H, and the investment of two units is about 5 million, which saves about 40% of energy.

[0034] The preferred embodiments of the present disclosure are described in detail above in combination with the drawings, but the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept range of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection range of the present disclosure.

[0035] In addition, it should be noted that various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present disclosure will not further describe various possible combination manners.

[0036] In addition, various different embodiments of the present disclosure can also be combined in any manner, as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A heating system, characterized in that The system comprises: a steam turbine for providing steam; a condenser in communication with the steam turbine for condensing the steam generated by the steam turbine into condensed water; a heater in communication with the condenser for heating the condensed water; a heat exchanger in communication with the heater for heating the return water of a heating network by using the heated condensed water as a heat exchange medium; the heater is provided with a plurality of heaters in series for gradually heating the condensed water, the heater is configured as a low-pressure heater, the low-pressure heater comprises a heating chamber for accommodating a heating medium and a heat exchange pipe for the condensed water to pass through, the heat exchange pipe is in communication with the condenser, the heating chamber is in communication with the steam turbine to heat the condensed water by using steam, the heating chambers of the plurality of low-pressure heaters are respectively in communication with the steam turbine to gradually heat the condensed water, and the heating system further comprises a recovery device in communication with the heating chamber to recover the heating medium and the condensed water after being heated.

2. The heating system according to claim 1, characterized in that At least two of the heaters are in communication with the heat exchanger through a switching valve.

3. The heating system according to claim 1, characterized in that, The recovery device comprises a hydrophobic expander and a deaerator, the heating chambers of the plurality of low-pressure heaters are in communication with the hydrophobic expander, the hydrophobic expander is in communication with the deaerator, and the hydrophobic expander is further used to communicate with a boiler.

4. The heating system according to claim 3, characterized in that The outlet end of the heat exchanger is in communication with the low-pressure heater close to the condenser through a recirculation pump, and the outlet end of the heat exchanger is connected to the heating chamber of the low-pressure heater to recover the waste heat of the condensed water.

5. The heating system according to claim 4, characterized in that The recirculation pump is provided with two in parallel.

6. The heating system of claim 2, wherein, The heater comprises a first heater, a second heater and a third heater connected in series, the switching valve comprises a first switching valve and a second switching valve, the first heater is in communication with the condenser, the second heater is in communication with the heat exchanger through the first switching valve, and the third heater is in communication with the heat exchanger through the second switching valve.

7. The heating system of claim 1, wherein, The heat exchanger is configured as a plate heat exchanger.

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