A low potential energy step heating system using ejectors

Abstract

The present invention discloses a low-level energy step heating and heat supply system using an ejector, the system comprising: ejectors of different models, exhaust steam reheaters of different models, the primary inlet of the ejector connected to the outlet of the exhaust steam reheater or other high-temperature and high-pressure steam source, the secondary inlet connected to the outlet of the steam turbine, the outlet of the ejector connected to the inlet of the hot side of the condenser; the hot side outlet of the condenser connected to the hot side inlet of the condensate condenser, the cold side inlet and outlet of the condenser connected to the supply and return water of the heat network circulating water; the cold side inlet of the condensate condenser connected to the return water of the heat network circulating water, the connection of the peak heater is basically the same as that of the condenser, except that its hot side inlet is directly connected to the medium-pressure cylinder of the steam turbine. The above system can fully recover the waste heat of exhaust steam, reduce the amount of air extraction, autonomously control the back pressure in the condenser, weaken the thermoelectric coupling, increase the heating capacity, and improve the energy utilization efficiency.

Description

Technical Field

[0001] The present invention relates to the field of clean heating technology, and in particular to a low-potential energy step-by-step heating system using an ejector. Background Art

[0002] Cogeneration is a centralized heating method commonly used in northern my country. Its transformation method has changed from traditional pure air extraction heating technology to more efficient high back pressure transformation heating technology or absorption heat pump heating technology. High back pressure transformation technology is widely used as a transformation scheme with high waste heat recovery efficiency and obvious energy saving effect. Among them, the transformation of the heating system of the Taikoo Heating Project is a successful case with high back pressure transformation technology as the core. The entire project mainly uses two technologies: high back pressure transformation and low-level energy cascade heating. It heats the circulating water step by step based on the principle that saturated water vapor has different saturation temperatures under different back pressures, so that the circulating water supply temperature meets user requirements. In the transformation of high back pressure technology, the back pressure in the condenser is mainly determined by the exhaust device of the steam turbine. In order to allow the exhaust steam to quickly enter the condenser, a vacuum pump is installed in the condenser. Therefore, the following problems are usually encountered in the actual operation of the heating system: the back pressure regulation in the condenser is limited, resulting in the limited regulation of the outlet temperature of the cooling water. The existence of the vacuum pump makes the back pressure in the condenser less than the exhaust back pressure of the steam turbine, resulting in an increase in the end difference. The heat exchange capacity of the condenser is only determined by the exhaust steam discharge and its back pressure. The heating capacity adjustment capacity is limited, and there is a thermoelectric coupling phenomenon. For this reason, we proposed a low-potential energy step heating heating system using an ejector. Summary of the invention

[0003] The present invention provides a low-level energy step-by-step heating and heat supply system using an ejector, the purpose of which is to fully recover exhaust steam waste heat, reduce the amount of air extraction, autonomously control the back pressure in the condenser, weaken the thermoelectric coupling, increase the heating capacity, and improve the energy utilization efficiency.

[0004] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0005] A low-level energy step-by-step heating and heat supply system using an ejector comprises a steam turbine, an ejector, an exhaust steam reheater, a condenser, a peak heater, a condensate condenser and other high-temperature and high-pressure steam sources, wherein the condenser and the peak heater are respectively provided with a cold side outlet, a cold side inlet and a hot side outlet, and a bypass is provided between the cold side outlet and the cold side inlet of the condenser; the primary inlet of the ejector is connected to the outlet of the high-pressure steam source of the exhaust steam reheater, the secondary inlet of the ejector is connected to the outlet of the steam turbine, and the A gate valve is installed at the outlet of the steam turbine, and the outlet of the ejector is connected to the inlet of the hot side; the hot side outlet of the condenser is connected to the hot side inlet of the condensate condenser, and the cold side inlet and cold side outlet on the condenser are both connected to the supply and return water of the hot network circulating water; the hot side outlet of the condensate condenser is connected to the steam turbine, the cold side inlet of the condensate condenser is connected to the hot network circulating water, and the cold side outlet of the condensate condenser is connected to the cold side inlet of the condenser; the inlet of the exhaust steam reheater is connected to the outlet of the steam turbine.

[0006] Preferably, in the above-mentioned low-energy step-heating heating system using an ejector, the inlet of the exhaust steam reheater is connected to the exhaust steam pipeline through a pipeline and an electric butterfly valve and an electric ball valve are provided on the pipeline.

[0007] Preferably, the above-mentioned low-level energy step heating and heat supply system using an ejector further includes a connecting bypass, which connects different high-temperature and high-pressure steam outlets, and an electric butterfly valve is provided on the pipeline of the connecting bypass.

[0008] Preferably, in the above-mentioned low-energy step-heating heating system using an ejector, the hot side inlet of the peak heater is directly connected to the intermediate pressure cylinder of the steam turbine.

[0009] Preferably, in the above-mentioned low-energy step-heating heating system using an ejector, the condensate condenser is provided with a condensate condenser inlet, a condensate condenser outlet and a heat network circulating water return pipe, the condensate condenser inlet is connected to the condensate condenser outlet by a pipeline, the condensate condenser outlet is connected to the water inlet of the turbine by a pipeline, the condensate condenser inlet is connected to the heat network circulating water return pipe, and electric butterfly valves are provided on the pipelines.

[0010] Preferably, in the above-mentioned low-potential energy step-heating heating system using an ejector, the other high-temperature and high-pressure steam source is connected to the ejector, and the other high-temperature and high-pressure steam source serves as the primary fluid of the ejector.

[0011] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention has the following obvious advantages: the back pressure in the condenser is jointly determined by the exhaust back pressure of the steam turbine and the steam parameters of the primary fluid of the ejector, and the adjustment is not limited by the steam turbine, reducing the occurrence of thermoelectric coupling phenomenon, and the outlet temperature of the cooling water is more controllable; the outlet temperature of the cooling water of the condenser is higher than the saturation temperature of the water vapor under the exhaust steam parameters of the steam turbine, and the heating capacity is further improved; the addition of the ejector can reduce the selection of the vacuum pump and reduce the power consumption; the exhaust steam reheater generates high-temperature and high-pressure steam by heating the exhaust steam, thereby reducing the energy consumption of high-temperature and high-pressure steam. In addition, for the safety and stability of the system The invention provides an alternative pipeline for the supply of other high-temperature and high-pressure steam; the setting of the condensate condenser can further reduce the temperature of the condensate, recover the waste heat to the greatest extent, eliminate the cold end loss, and make the energy utilization rate of the entire waste heat recovery device reach 100%; the use of the peak heater ensures the supply of high-temperature circulating water in extremely cold weather, and can be used as an alternative heat source for other condensers in the heating system in non-severe cold seasons; the series use of multiple groups of equipment not only ensures the recovery of low back pressure exhaust steam waste heat, but also ensures the heating capacity of the heating system, and can avoid the occurrence of heating problems caused by the failure of a certain group of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0013] Figure 1 The schematic diagram is a structural diagram of a low-potential energy step-heating heating system equipped with an ejector.

[0014] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0015] 1. Steam turbine; 2. Ejector; 3. Exhaust steam reheater; 4. Condenser; 5. Peak heater; 6. Condensate condenser; 7. Gate valve; 8. Electric butterfly valve; 9. Electric ball valve; 10. Interconnection bypass; 11. Bypass; 12. Cold side outlet; 13. Cold side inlet; 14. Hot side outlet; 15. Condensate condenser inlet; 16. Condensate condenser outlet; 17. Heat network circulating water return pipe; 18. Heat network circulating water; 19. Other high-temperature and high-pressure steam sources. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 As shown, this embodiment is a low-level energy step heating and heating system using an ejector, comprising a steam turbine 1, an ejector 2, an exhaust steam reheater 3, a condenser 4, a peak heater 5, a condensate condenser 6 and other high-temperature and high-pressure steam sources 19, the condenser 4 and the peak heater 5 are respectively provided with a cold side outlet 12, a cold side inlet 13, and a hot side outlet 14, a bypass 11 is provided between the cold side outlet 12 and the cold side inlet 13 of the condenser 4; the primary inlet of the ejector 2 is connected to the outlet of the high-pressure steam source of the exhaust steam reheater 3, the secondary inlet of the ejector 2 is connected to the outlet of the steam turbine 1 The outlet of the steam turbine 1 is connected to the hot side inlet, the gate valve 7 is installed at the outlet of the steam turbine 1, and the outlet of the ejector 2 is connected to the hot side inlet; the hot side outlet 14 of the condenser 4 is connected to the hot side inlet of the condensate condenser 6, and the cold side inlet 13 and the cold side outlet 12 on the condenser 4 are both connected to the supply and return water of the hot network circulating water 18; the hot side outlet 14 of the condensate condenser 6 is connected to the steam turbine 1, the cold side inlet 13 of the condensate condenser 6 is connected to the hot network circulating water 18, and the cold side outlet 12 of the condensate condenser 6 is connected to the cold side inlet 13 of the condenser 4; the inlet of the exhaust steam reheater 3 is connected to the outlet of the steam turbine 1;

[0018] The ejector 2 is a steam ejector, which uses high-temperature and high-pressure steam to eject exhaust steam and thus increase the back pressure in the condenser 4. On the one hand, it can increase the discharge temperature of the condensed water, reduce the end difference, and increase the heating capacity; on the other hand, it can achieve the purpose of flexibly adjusting the back pressure of the condenser 4 and reduce the thermoelectric coupling effect of the steam turbine 1.

[0019] The inlet of the exhaust steam reheater 3 is connected to the exhaust steam pipeline through a pipeline, and an electric butterfly valve 8 and an electric ball valve 9 are arranged on the pipeline. The exhaust steam discharged from the steam turbine 1 is heated to generate high-temperature and high-pressure steam as the primary fluid of the ejector 2 for use by the ejector, which is also the most economical primary fluid acquisition scheme in the present invention. The parameters of the exhaust steam reheater 3 of different groups of equipment are different;

[0020] The condenser 4 is divided into hot and cold sides, the hot side inlet is connected to the outlet of the ejector 2 through a pipeline, the hot side outlet 14 is connected to the water inlet of the steam turbine 1 or the inlet of the steam turbine 1 through a pipeline, and the cold side outlet 12 is connected to the circulating water 18 of the heat network. It is the main device for waste heat recovery, and the parameters of the condenser 4 of different groups of equipment are different;

[0021] The peak heater 5 is similar to the condenser 4 mentioned above, and the connection method and the like are the same, the only difference being that the hot side inlet of the peak heater 5 is directly connected to the intermediate pressure cylinder of the steam turbine 1, thereby increasing the heating capacity;

[0022] The condensate condenser 6 is provided with a condensate condenser inlet 15, a condensate condenser outlet 16 and a heat network circulating water return pipe 17. The condensate condenser inlet 15 is connected to the condensate condenser outlet 16 through a pipeline. The condensate condenser outlet 16 is connected to the water inlet of the steam turbine 1 through a pipeline. The condensate condenser inlet 15 is connected to the heat network circulating water return pipe 17. An electric butterfly valve 8 is provided on the pipeline. The condensate condenser 6 is another device for waste heat recovery, which is mainly used for waste heat recovery of condensate from a higher back pressure condenser 4. The parameters of the condensate condensers 6 of different groups of equipment are different.

[0023] The other high-temperature and high-pressure steam source 19 is connected to the ejector 2, and the other high-temperature and high-pressure steam source 19 is used as the primary fluid of the ejector 2, as an alternative solution for the primary fluid of the ejector, the purpose of which is to prevent the exhaust steam reheater 3 from failing and causing the heating system to not work properly, and on the other hand, to adjust the heat exchange of the condenser 4 by adjusting the steam flow rate and back pressure, thereby reducing the thermoelectric coupling of the steam turbine 1;

[0024] It also includes a communication bypass 10, which connects different high-temperature and high-pressure steam outlets, and an electric butterfly valve 8 is provided on the pipeline of the communication bypass 10, which can be used as an emergency solution when different equipment is overhauled or fails; a communication bypass 10 is also set between each group of equipment to achieve random combination of multiple groups of equipment and avoid affecting the normal operation of heating due to the failure or maintenance of a certain group of equipment. In addition, when the user has a high demand for temperature, the peak heater 5 can be started, and its hot side uses higher quality steam, which can achieve higher temperature circulating water supply.

[0025] When the present invention is working, the exhaust steam with waste heat is discharged from the steam turbine 1 and enters the condenser 4 under the injection of the ejector 2. In this process, the ejector 2 can freely adjust the back pressure in the condenser 4 by changing the parameters of the ejector 2, and flexibly adjust the outlet water temperature of the cooling water and the outlet water temperature of the condenser 4. Then the condensed water enters the condensate condenser 6 through the pipeline, and the temperature of the condensed water is further reduced by the condensate condenser 6, so as to improve the utilization efficiency of energy. The circulating water, as a carrier for waste heat recovery, mainly obtains heat through heat exchange with the condenser 4, and is supplemented by the condensate cooler to obtain heat. By adjusting the switch of the bypass 11 pipeline, the circulating cooling water can pass through the condenser 4 with different back pressures (the back pressure is increased in steps) to meet the user's requirements for different water supply temperatures. In order to effectively recover the waste heat in the condensate, the cooling water inlet of different groups of condensate coolers comes from the circulating water return water, and the outlet water is connected to the inlet of the condenser 4 of this group of equipment. The primary fluid of the ejector 2 is mainly obtained through the exhaust steam reheater 3. For safety reasons, other optional high-temperature and high-pressure steam inlets are also provided.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0027] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A low-potential step-heating heating system using an ejector, comprising a steam turbine (1), an ejector (2), an exhaust steam reheater (3), a condenser (4), a peak heater (5), a condensate condenser (6) and other high-temperature and high-pressure steam sources (19), characterized in that: The condenser (4) and the peak heater (5) are respectively provided with a cold side outlet (12), a cold side inlet (13), and a hot side outlet (14); a bypass (11) is provided between the cold side outlet (12) and the cold side inlet (13) of the condenser (4); the primary inlet of the ejector (2) is connected to the outlet of the high-pressure steam source of the exhaust steam reheater (3); the secondary inlet of the ejector (2) is connected to the outlet of the steam turbine (1); the outlet of the steam turbine (1) is provided with a gate valve (7); the outlet of the ejector (2) is connected to the inlet of the hot side; the The hot side outlet (14) is connected to the hot side inlet of the condensate condenser (6), and the cold side inlet (13) and the cold side outlet (12) on the condenser (4) are both connected to the supply and return water of the heat network circulating water (18); the hot side outlet (14) of the condensate condenser (6) is connected to the steam turbine (1), the cold side inlet (13) of the condensate condenser (6) is connected to the heat network circulating water (18), and the cold side outlet (12) of the condensate condenser (6) is connected to the cold side inlet (13) of the condenser (4); the inlet of the exhaust steam reheater (3) is connected to the outlet of the steam turbine (1); The inlet of the exhaust steam reheater (3) is connected to the exhaust steam pipeline through a pipeline, and the pipeline is provided with an electric butterfly valve (8) and an electric ball valve (9); The condensate condenser (6) is provided with a condensate condenser inlet (15), a condensate condenser outlet (16) and a heat network circulating water return pipe (17); the condensate condenser inlet (15) is connected to the condensate condenser outlet (16) via a pipeline; the condensate condenser outlet (16) is connected to the water inlet of the steam turbine (1) via a pipeline; the condensate condenser inlet (15) is connected to the heat network circulating water return pipe (17); and electric butterfly valves (8) are provided on the pipelines.

2. A low-potential energy step-by-step heating and heat supply system using an ejector according to claim 1, characterized in that: It also includes a connecting bypass (10), wherein the connecting bypass (10) connects different high-temperature and high-pressure steam outlets, and an electric butterfly valve (8) is provided on the pipeline of the connecting bypass (10).

3. A low-potential energy step-by-step heating and heat supply system using an ejector according to claim 1, characterized in that: The hot side inlet of the peak heater (5) is directly connected to the intermediate pressure cylinder of the steam turbine (1).

4. A low-potential energy step-by-step heating and heat supply system using an ejector according to claim 1, characterized in that: The other high-temperature and high-pressure steam source (19) is connected to the ejector (2), and the other high-temperature and high-pressure steam source (19) serves as the primary fluid of the ejector (2).

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