Thermodynamic system for stable operation of combined cooling heating and power back pressure unit in non-heating season

Abstract

The utility model relates to a thermodynamic system for stable operation of a combined cooling heating and power back pressure unit in a non-heating season. The thermodynamic system comprises a boiler subsystem, a back pressure turbine unit, a heat supply network heat exchanger, a heat supply network water return pipe, a heat supply network water supply pipe and a cooling subsystem. The boiler subsystem and the backpressure turbine unit are sequentially connected to supply steam; a steam inlet of the heat supply network heat exchanger is connected with a steam exhaust port of the backpressure turboset, a water return port is connected with a water return port of the boiler subsystem, a water inlet is connected with a heat supply network water return pipe, and a water outlet is connected with a heat supply network water supply pipe; a water inlet of the cooling subsystem is connected with the heat supply network water return pipe and the heat supply network water supply pipe, and a water outlet is connected with the heat supply network water return pipe. The thermodynamic system is provided with three heat exchange loops, operates under different adjustments of the unit, and can absorb redundant exhaust steam heat of the backpressure turbine unit so as to adapt to periodic changes of domestic hot water and cold supply loads in non-heating seasons, and stable operation of the combined cooling heating and power backpressure unit in the non-heating seasons is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal systems, in particular to a thermal system for a combined cooling, heating and power (CCHP) back-pressure unit that operates stably in the non-heating season. Background Art

[0002] The "heat-based electricity" operating mode of the back-pressure unit determines its suitability for application scenarios with stable cooling and heating load demands. For trigeneration back-pressure units, if there is no stable industrial heating load from the outside during the non-heating season, it is difficult to ensure stable operation of the unit by relying solely on the domestic hot water and cooling loads that vary significantly every day. When the external domestic hot water and cooling loads are very small or basically non-existent during a certain period of time, the exhaust heat of the back-pressure unit cannot be absorbed and the unit cannot operate; when the external domestic hot water and cooling loads are in high demand, the unit needs to operate at a higher load. The unit needs to be frequently started and stopped and the load adjusted, which brings a series of difficulties to operation and makes actual grid dispatching difficult to achieve. Utility Model Content

[0003] The utility model provides a thermal system for a trigeneration back-pressure unit to operate stably in the non-heating season. The system has three heat exchange circuits and operates under different adjustments of the unit. It can absorb excess exhaust heat of the back-pressure steam turbine unit to adapt to the periodic changes of domestic hot water and cooling loads in the non-heating season, thereby achieving stable operation of the trigeneration back-pressure unit in the non-heating season.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A thermal system for a combined cooling, heating and power (CCHP) back-pressure unit that operates stably in the non-heating season, comprising a boiler subsystem, a back-pressure steam turbine unit, a heat network heat exchanger, a heat network return pipe, a heat network supply pipe, and a cooling subsystem;

[0006] The boiler subsystem and the back-pressure steam turbine unit are connected in sequence to supply steam;

[0007] The steam inlet of the heat network heat exchanger is connected to the exhaust port of the back pressure steam turbine unit, the return port is connected to the return port of the boiler subsystem, the water inlet is connected to the return pipe of the heat network, and the water outlet is connected to the water supply pipe of the heat network;

[0008] The water inlet of the above-mentioned cooling subsystem is connected to the above-mentioned heat network return pipe and the above-mentioned heat network water supply pipe, and the water outlet is connected to the above-mentioned heat network return pipe. The connection point between the water inlet of the above-mentioned cooling subsystem and the above-mentioned heat network return pipe and the connection point between the water outlet and the above-mentioned heat network return pipe are arranged along the water flow direction in the above-mentioned heat network return pipe.

[0009] Preferably, the water inlet of the cooling subsystem is connected to a water inlet cooling pipe and a water return cooling pipe, and the water outlet is connected to a water outlet cooling pipe;

[0010] A first control valve is installed at the water inlet of the above-mentioned heat network return pipe, and a second control valve is installed at the water outlet of the above-mentioned heat network water supply pipe;

[0011] The return water cooling pipe is connected to both the heat network return pipe and the heat network water supply pipe, the inlet water cooling pipe is connected to the heat network return pipe, and the return water cooling pipe, the inlet water cooling pipe and the heat network return pipe are connected at one point, a third control valve is installed on the return water cooling pipe, and a fourth control valve is installed at the water inlet of the inlet water cooling pipe;

[0012] The above-mentioned outlet cooling pipe is connected to the above-mentioned heat network return pipe, and a fifth control valve is installed at the water outlet;

[0013] A sixth control valve is installed on the heat network return pipe between the connection point of the water inlet cooling pipe and the heat network return pipe and the connection point of the water outlet cooling pipe and the heat network return pipe.

[0014] Preferably, the first control valve, the second control valve, the third control valve, the fourth control valve, the fifth control valve and the sixth control valve are all solenoid valves.

[0015] Preferably, the cooling subsystem includes a circulating water heat exchanger and a cooling tower;

[0016] The hot end water inlet of the above-mentioned circulating water heat exchanger is connected to the above-mentioned water inlet cooling pipe, the hot end water outlet is connected to the above-mentioned water outlet cooling pipe, and the cold end water inlet and outlet of the above-mentioned circulating water heat exchanger are both connected to the above-mentioned cooling tower.

[0017] Preferably, the boiler subsystem includes a gas turbine and a waste heat boiler, the gas turbine and the waste heat boiler are connected, and the return water port of the heat network heat exchanger is connected to the return water port of the boiler subsystem.

[0018] Preferably, the water supply pipe of the heating network is externally connected to a refrigerator and the heating network.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The heat network return pipe, heat network supply pipe and cooling subsystem can be connected to form three heat exchange circuits, which can be switched under different operating conditions of the unit to absorb the excess exhaust heat of the back-pressure steam turbine unit to adapt to the periodic changes in domestic hot water and cooling loads in the non-heating season, and realize the stable operation of the trigeneration back-pressure unit in the non-heating season.

[0021] 2. The cooling subsystem and the heat network return pipe are used in series. The heat exchange circuit formed by the heat network return pipe, the cooling subsystem and the heat network water supply pipe can allow the heat network circulating water with a lower temperature to enter the heat network heat exchanger, so that more exhaust heat of the back pressure steam turbine unit can be consumed in the heat network heat exchanger, and the external heating and cooling can be met, thereby better regulating the back pressure steam turbine unit and achieving better regulation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a schematic diagram of the overall system of an embodiment of the present utility model;

[0024] Figure 2 This is a schematic diagram of the first heat exchange circuit in an embodiment of the present utility model;

[0025] Figure 3 This is a schematic diagram of the second heat exchange circuit in an embodiment of the present utility model;

[0026] Figure 4 This is a schematic diagram of the third heat exchange circuit in an embodiment of the present utility model.

[0027] Description of reference numerals:

[0028] 1. Gas turbine; 2. Waste heat boiler; 3. Back-pressure steam turbine unit; 4. Steam supply pipeline; 5. Unit return pipeline; 6. First water pump; 7. Heating network heat exchanger; 8. Heating network return pipe; 9. Heating network supply pipe; 10. Second water pump; 11. Cooling subsystem; 111. Circulating water heat exchanger; 112. Cooling tower; 113. Third water pump; 12. Inlet cooling pipe; 13. Outlet cooling pipe; 14. Return cooling pipe; 15. First control valve; 16. Second control valve; 17. Third control valve; 18. Fourth control valve; 19. Fifth control valve; 20. Sixth control valve. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] 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 positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0032] The present invention provides a thermal system for a trigeneration back pressure unit that operates stably in the non-heating season. Figure 1 As shown, it specifically includes a boiler subsystem, a back-pressure steam turbine unit 3, a heat network heat exchanger 7, a heat network return pipe 8, a heat network water supply pipe 9 and a cooling subsystem 11, wherein the boiler subsystem and the back-pressure steam turbine unit 3 are connected in sequence. In this embodiment, the boiler subsystem includes a gas turbine 1 and a waste heat boiler 2. The gas turbine 1 and the waste heat boiler 2 are connected to supply steam to the back-pressure steam turbine unit 3. The heat network return pipe 8, the heat network water supply pipe 9 and the cooling subsystem 11 are used in conjunction with the heat network heat exchanger 7 to absorb the steam generated by the back-pressure steam turbine unit 3, and jointly complete the regulation of the heating steam of the back-pressure unit.

[0033] Specifically, a steam supply pipe 4 is connected between the steam inlet of the heat network heat exchanger 7 and the exhaust port of the back pressure steam turbine unit 3, and the return port and the return port of the waste heat boiler 2 are connected to the unit return pipe 5, and a first water pump 6 is installed in the unit return pipe 5. The steam supply pipe 4, the unit return pipe 5 and the first water pump 6 are connected to form a supply loop of circulating water in the unit. During normal operation of the unit, this supply loop operates normally; correspondingly, the water inlet of the heat network heat exchanger 7 is connected to the heat network return pipe 8, and the water outlet is connected to the heat network water supply pipe 9. At the same time, the water inlet of the cooling subsystem 11 is connected to the heat network return pipe 8. It is connected to both the heat network return pipe 8 and the heat network water supply pipe 9, the water outlet is connected to the heat network return pipe 8, and the connection point of the water inlet of the cooling subsystem 11 and the heat network return pipe 8 and the connection point of the water outlet and the heat network return pipe 8 are arranged along the water flow direction in the heat network return pipe 8, thereby forming three heat exchange circuits. The three heat exchange circuits operate in different stages of the back pressure steam turbine unit 3 respectively, and exchange heat with the circulating water supply circuit in the unit in the heat network heat exchanger 7 to adapt to the periodic changes of domestic hot water and cooling loads in the non-heating season, realize thermoelectric decoupling, and ensure stable operation of the unit.

[0034] Specifically, the three circuits and operating conditions are as follows: Figure 2 As shown, the first heat exchange circuit: when the domestic hot water and cooling load demand is high enough to absorb the exhaust heat of the back pressure steam turbine unit 3, the heat network return pipe 8, the second water pump 10 on the heat network return pipe 8, and the heat network supply pipe 9 are connected to form a heat exchange circuit, and the cooling subsystem 11 is not running. The heat exchange circuit and the supply circuit of the circulating water in the unit are in the heat network heat exchanger 7 so that the steam and the heat network circulating water exchange heat to provide normal heating and cooling to the outside world; Figure 3 As shown, the second heat exchange circuit: when the demand for domestic hot water and cooling load is small and insufficient to absorb the exhaust heat of the back-pressure steam turbine unit 3, the water inlet and outlet of the cooling subsystem 11 are both connected to the heat network return pipe 8, and the water inlet of the cooling subsystem 11 is not connected to the heat network supply pipe 9, so that the cooling subsystem 11 and the heat network return pipe 8 are used in series. The heat network return pipe 8, the cooling subsystem 11, and the heat network supply pipe 9 are connected to form a heat exchange circuit, and the supply circuit of the circulating water in the unit is used to exchange heat between the steam and the heat network circulating water in the heat network heat exchanger 7 to remove To provide normal heating and cooling to the outside world, the cooling subsystem 11 and the heat network return pipe 8 are used in series because the external domestic hot water and cooling load demand are small and the return water temperature is relatively higher. The heat network circulating water is first cooled before entering the heat network heat exchanger 7, so that the temperature of the heat network circulating water is reduced. Then the heat network circulating water with a lower temperature enters the heat network heat exchanger 7, so that more exhaust heat of the back pressure steam turbine unit 3 can be consumed in the heat network heat exchanger 7, and the external heating and cooling can be met, thereby better regulating the back pressure steam turbine unit 3 and achieving a better regulation effect; Figure 4As shown in the third heat exchange loop: when the domestic hot water and cooling loads are zero, the heat network return pipe 8 and the heat network supply pipe 9 are disconnected from the external heat network. The water inlet and outlet of the cooling subsystem 11 are both connected to the heat network return pipe 8 for use. The water inlet of the cooling subsystem 11 is connected to the heat network supply pipe 9, thereby forming a closed heat exchange loop with the cooling subsystem 11, part of the heat network return pipe 8, and part of the heat network supply pipe 9. Of course, the circulating water needs to be supplied externally. In the heat network heat exchanger 7, the circulating water continuously exchanges heat with the exhaust steam of the back-pressure steam turbine unit 3, and then is cooled in the cooling subsystem 11 to dissipate the heat, completing the consumption of the exhaust steam heat of the back-pressure steam turbine unit 3 and achieving the purpose of regulating the back-pressure steam turbine unit 3. In this embodiment, the heat network supply pipe 9 is connected to the external heat network to supply heat to the outside. At the same time, the heat network supply pipe 9 is also connected to a refrigeration device such as a refrigerator to provide it with a heat source and to supply cooling to the outside.

[0035] Specifically, the water inlet of the cooling subsystem 11 is connected to the water inlet cooling pipe 12 and the return water cooling pipe 14, and the water outlet is connected to the outlet cooling pipe 13, wherein the water inlet of the heat network return pipe 8 is installed with a first control valve 15, and the water outlet of the heat network water supply pipe 9 is installed with a second control valve 16, the return water cooling pipe 14 is connected to the heat network return pipe 8 and the heat network water supply pipe 9, the water inlet cooling pipe 12 is connected to the heat network return pipe 8, and the return water cooling pipe 14, the water inlet cooling pipe 12 and the heat network return pipe 8 are connected at one place, and the return water cooling pipe 14 is installed with a third control valve. Valve 17, a fourth control valve 18 is installed at the water inlet of the water inlet cooling pipe 12, the water outlet cooling pipe 13 is connected to the heat network return pipe 8, and a fifth control valve 19 is installed at the water outlet, and a sixth control valve 20 is installed on the heat network return pipe 8 between the connection between the water inlet cooling pipe 12 and the heat network return pipe 8 and the connection between the water outlet cooling pipe 13 and the heat network return pipe 8. The formation of three heat exchange circuits can be controlled by the first control valve 15, the second control valve 16, the third control valve 17, the fourth control valve 18, the fifth control valve 19 and the sixth control valve 20. Specifically, as Figure 2 As shown, the first control valve 15, the second control valve 16, and the sixth control valve 20 are closed, and the other control valves are disconnected, so that the heat network return pipe 8, the second water pump 10 on the heat network return pipe 8, and the heat network water supply pipe 9 are connected to form a first heat exchange circuit; Figure 3 As shown, the first control valve 15, the second control valve 16, the fourth control valve 18, and the fifth control valve 19 are closed, and the other control valves are disconnected. The cooling subsystem 11, the heat network return pipe 8, and the heat network supply pipe 9 are connected to form a second heat exchange circuit; Figure 4 As shown, the third control valve 17, the fourth control valve 18 and the fifth control valve 19 are closed, and the other control valves are opened. The cooling subsystem 11, part of the heat network return pipe 8 and part of the heat network supply pipe 9 form a closed-loop third heat exchange circuit.

[0036] Specifically, the first control valve 15, the second control valve 16, the third control valve 17, the fourth control valve 18, the fifth control valve 19 and the sixth control valve 20 are all solenoid valves. The unit can automatically switch the on and off of each control valve under different operating conditions to achieve automatic operation.

[0037] Specifically, the cooling subsystem 11 includes a circulating water heat exchanger 111 and a cooling tower 112, wherein the hot end water inlet of the circulating water heat exchanger 111 is connected to the water inlet cooling pipe 12, and the hot end water outlet is connected to the water outlet cooling pipe 13, and the cold end water inlet and outlet of the circulating water heat exchanger 111 are respectively connected to the cooling tower 112 via a cooling water return pipe and a cooling water inlet pipe, wherein a third water pump 113 is installed on the cooling water return pipe for circulating the cooling circulating water. The circulating water in the heat network exchanges heat with the cooling water in the circulating water heat exchanger 111, and then the cooling water is cooled in the cooling tower 112 to dissipate the heat into the atmosphere, thereby completing the absorption of the exhaust heat of the back-pressure steam turbine unit 3.

[0038] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A thermal system for trigeneration of cooling, heating and power with a back-pressure unit that operates stably in the non-heating season, characterized in that: Including boiler subsystem, back pressure steam turbine unit, heat network heat exchanger, heat network return pipe, heat network water supply pipe and cooling subsystem; The boiler subsystem and the back-pressure steam turbine unit are connected in sequence to supply steam; The steam inlet of the heat network heat exchanger is connected to the exhaust port of the back pressure steam turbine unit, the return water port is connected to the return water port of the boiler subsystem, the water inlet is connected to the heat network return pipe, and the water outlet is connected to the heat network water supply pipe; The water inlet of the cooling subsystem is connected to both the heat network return pipe and the heat network water supply pipe, and the water outlet is connected to the heat network return pipe. The connection point between the water inlet of the cooling subsystem and the heat network return pipe and the connection point between the water outlet and the heat network return pipe are arranged along the water flow direction in the heat network return pipe.

2. The thermal system according to claim 1, characterized in that The water inlet of the cooling subsystem is connected to a water inlet cooling pipe and a water return cooling pipe, and the water outlet is connected to a water outlet cooling pipe; A first control valve is installed at the water inlet of the heat network return pipe, and a second control valve is installed at the water outlet of the heat network water supply pipe; The return water cooling pipe is connected to both the heat network return water pipe and the heat network water supply pipe, the inlet water cooling pipe is connected to the heat network return water pipe, and the return water cooling pipe, the inlet water cooling pipe and the heat network return water pipe are connected at one point, a third control valve is installed on the return water cooling pipe, and a fourth control valve is installed at the water inlet of the inlet water cooling pipe; The outlet cooling pipe is connected to the heat network return pipe, and a fifth control valve is installed at the water outlet; A sixth control valve is installed on the heat network return pipe between the connection point of the water inlet cooling pipe and the heat network return pipe and the connection point of the water outlet cooling pipe and the heat network return pipe.

3. The thermal system according to claim 2, characterized in that The first control valve, the second control valve, the third control valve, the fourth control valve, the fifth control valve, and the sixth control valve are all solenoid valves.

4. The thermal system according to claim 2, characterized in that The cooling subsystem includes a circulating water heat exchanger and a cooling tower; The hot end water inlet of the circulating water heat exchanger is connected to the water inlet cooling pipe, the hot end water outlet is connected to the water outlet cooling pipe, and the cold end water inlet and outlet of the circulating water heat exchanger are both connected to the cooling tower.

5. The thermal system according to claim 1, characterized in that The boiler subsystem includes a gas turbine and a waste heat boiler. The gas turbine and the waste heat boiler are connected. The return water port of the heat network heat exchanger is connected to the return water port of the boiler subsystem.

6. The thermal system according to claim 1, characterized in that The heat network water supply pipe is externally connected with a refrigerator and a heat network.

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