A gas-steam combined cycle waste heat supply system

Abstract

The application belongs to the technical field of combined heat and power supply, and particularly relates to a gas-steam combined cycle waste steam heat supply system, which comprises a gas turbine, a first heat exchange part connected with the gas turbine, a steam turbine connected with the first heat exchange part, a second heat exchange part and a cooling mechanism connected with the steam turbine, a user heat supply part connected with the second heat exchange part, a first valve arranged between the steam turbine and the second heat exchange part, a second valve arranged between the steam turbine and the cooling mechanism, and the cooling mechanism and the second heat exchange part being connected with the first heat exchange part. The application can realize large-area heating without extracting high-quality steam and improving the steam turbine exhaust parameter, and the second heat exchange part can bear part or all of the cooling load of the cooling mechanism, so that the power consumption of the cooling mechanism is reduced or zero, energy is saved, and the overall efficiency of the combined cycle is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of combined heat and power, and particularly relates to a waste steam heat supply system of a gas-steam combined cycle. BACKGROUND

[0002] A renewable energy power system mainly based on solar energy and wind energy has the characteristics of randomness, volatility and intermittency, and its large-scale grid connection requires real-time output adjustment of other power systems to adapt to the frequent changes of renewable energy power. At present, gas turbines are mostly used as ideal peak shaving power sources for renewable energy power to adapt to variable power load demands due to their high efficiency, low pollution and good peak shaving performance.

[0003] When a back pressure gas-steam turbine combined heat and power cycle is operated, the exhaust pressure needs to be above 0.1 MPa, that is, the corresponding exhaust temperature is above 100 DEG C. Compared with a conventional Rankine cycle power plant with an exhaust pressure of 50 kPa, the power generation capacity is obviously reduced. In a extraction gas turbine combined heat and power cycle, part of the steam that should flow to the low-pressure cylinder for power generation is extracted for heating, which also greatly reduces the power generation capacity.

[0004] The two types of "heat determines electricity" modes used by the above-mentioned gas-steam combined cycle cogeneration unit are, to some extent, an operation mode of "electricity for heat". The electricity-heat ratio is seriously dependent on the heat demand, and if the heat and power unit develops the maximum heat supply capacity, the power output cannot be adjusted. In this way, during the winter peak period, the contradiction between electricity and heat is very serious, and it is even more impossible to bear the power peak shaving of renewable energy. SUMMARY

[0005] The purpose of the application is to provide a waste steam heat supply system of a gas-steam combined cycle to solve the above-mentioned problems.

[0006] To achieve the above-mentioned purpose, the application provides the following scheme.

[0007] A waste steam heat supply system of a gas-steam combined cycle, comprising: a gas turbine, the gas turbine being communicated with a first heat exchange part, the first heat exchange part being communicated with a steam turbine, the steam turbine being communicated with a second heat exchange part and a cooling mechanism, the second heat exchange part being communicated with a user heat supply part, a first valve being arranged between the steam turbine and the second heat exchange part, a second valve being arranged between the steam turbine and the cooling mechanism, the cooling mechanism and the second heat exchange part both being communicated with the first heat exchange part.

[0008] Preferably, the first heat exchange part comprises a first heat exchange box communicated with the gas turbine, a superheater, a steam generator and an economizer are arranged in the first heat exchange box, an outlet of the superheater extends out of the first heat exchange box and is communicated with the steam turbine, an inlet of the superheater is communicated with an outlet of the steam generator, an inlet of the steam generator is communicated with an outlet of the economizer, and an inlet of the economizer is communicated with the cooling mechanism and the second heat exchange part.

[0009] Preferably, the second heat exchange part comprises a compression heat pump communicated with the steam turbine, the first valve is located between the steam turbine and the compression heat pump, and a water outlet of the compression heat pump is communicated with an inlet of the economizer.

[0010] Preferably, the user heat supply part comprises a heat user communicated with the compression heat pump, and a booster pump is arranged between the compression heat pump and the heat user.

[0011] Preferably, the cooling mechanism comprises a condenser communicated with the steam turbine, the second valve is arranged between the condenser and the steam turbine, and the condenser is communicated with the economizer.

[0012] Preferably, the condenser is provided with a heat dissipation circulating pipeline, one end of the heat dissipation circulating pipeline extends out of the condenser and is respectively communicated with a water inlet of a cooling tower, the other end of the heat dissipation circulating pipeline extends out of the condenser and is communicated with a water outlet of a circulating water pump, and a water inlet of the circulating water pump is communicated with a water outlet of the cooling tower.

[0013] Preferably, a water outlet of the condenser is communicated with a fourth valve, a water inlet of one of a second three-way pipe of the fourth valve is communicated, a water outlet of the compression heat pump is communicated with a third valve, the third valve is communicated with a water inlet of the other of the second three-way pipe, a water outlet of the second three-way pipe is communicated with a condensate pump, and the condensate pump is communicated with the economizer.

[0014] Preferably, an air inlet of the first heat exchange box is communicated with a flue gas outlet of the gas turbine, and an air outlet of the first heat exchange box is communicated with a chimney.

[0015] Preferably, an air inlet of the first three-way pipe is communicated with an air outlet of the steam turbine, and two air outlets of the first three-way pipe are respectively communicated with the first valve and the second valve.

[0016] Compared with the prior art, the present application has the following advantages and technical effects:

[0017] In the present application, the steam turbine outlet exhaust steam enters the second heat exchange part, and then enters the first heat exchange part after heating the user heating part; part of the exhaust steam enters the cooling mechanism, and enters the first heat exchange part after condensation; the flue gas generated by the gas turbine enters the first heat exchange part, heats the condensed water entering the first heat exchange part, and the condensed water in the first heat exchange part is heated to generate high-temperature and high-pressure steam entering the steam turbine to drive the steam turbine to generate electricity; in this process, the first valve and the second valve are controlled to control the amount of exhaust steam flowing into the second heat exchange part and the cooling mechanism, so that the second heat exchange part bears part or all of the cooling load of the cooling mechanism.

[0018] The present application improves the low-grade exhaust steam heat generated by the steam turbine, uses the waste heat of the combined cycle for heating, and realizes efficient combined heat and power supply. Not only can large-area heating be realized without extracting high-quality steam and improving the exhaust parameters of the steam turbine, but also the second heat exchange part can bear part or all of the cooling load of the cooling mechanism, so that the power consumption of the cooling mechanism is reduced or zero, energy is saved, and the overall efficiency of the combined cycle is improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The structure of the present application is shown in the figure;

[0021] Among them, 1, gas turbine; 2, steam turbine; 3, condenser; 4, condensate pump; 5, coal economizer; 6, steam generator; 7, superheater; 8, circulating water pump; 9, cooling tower; 10, chimney; 11, compression heat pump; 12, heat user; 13, booster pump; 14, first three-way valve; 15, second three-way valve; 16, first valve; 17, second valve; 18, third valve; 19, fourth valve. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0023] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0024] With reference to Figure 1 The present application provides a gas-steam combined cycle waste steam heat supply system, comprising: a gas turbine 1, the gas turbine 1 being communicated with a first heat exchange part, the first heat exchange part being communicated with a steam turbine 2, the steam turbine 2 being communicated with a second heat exchange part and a cooling mechanism, the second heat exchange part being communicated with a user heat supply part, a first valve 16 being arranged between the steam turbine 2 and the second heat exchange part, a second valve 17 being arranged between the steam turbine 2 and the cooling mechanism, and the cooling mechanism and the second heat exchange part both being communicated with the first heat exchange part.

[0025] In the present application, part of the waste steam from the outlet of the steam turbine 2 enters the second heat exchange part to supply heat to the user heat supply part, and then enters the first heat exchange part; part of the waste steam enters the cooling mechanism, and after being condensed, enters the first heat exchange part; the flue gas generated by the gas turbine 1 enters the first heat exchange part to heat the condensed water entering the first heat exchange part, and the condensed water is heated in the first heat exchange part to generate high-temperature and high-pressure water vapor which enters the steam turbine 2 to drive the steam turbine 2 to generate power; in this process, by controlling the first valve 16 and the second valve 17, the amount of waste steam flowing into the second heat exchange part and the cooling mechanism is controlled, so that the second heat exchange part bears part or all of the cooling load of the cooling mechanism.

[0026] Further optimization scheme, the first heat exchange part comprises a first heat exchange box communicated with the gas turbine 1, a superheater 7, a steam generator 6 and an economizer 5 are arranged in the first heat exchange box, the outlet of the superheater 7 extends out of the first heat exchange box and is communicated with the steam turbine 2, the inlet of the superheater 7 is communicated with the outlet of the steam generator 6, the inlet of the steam generator 6 is communicated with the outlet of the economizer 5, and the inlet of the economizer 5 is communicated with the cooling mechanism and the second heat exchange part.

[0027] The high-temperature flue gas generated by the gas turbine 1 enters the first heat exchange box, the economizer 5 recycles the heat of the flue gas, heats the condensed water flowing through the economizer 5, and then the condensed water enters the steam generator 6 to become steam, the steam enters the superheater 7 to become superheated steam, and then enters the steam turbine 2 to drive the steam turbine 2 to generate power.

[0028] Further optimization scheme, the second heat exchange part comprises a compression heat pump 11 communicated with the steam turbine 2, the first valve 16 is located between the steam turbine 2 and the compression heat pump 11, and the outlet of the compression heat pump 11 is communicated with the inlet of the economizer 5.

[0029] The low-grade exhaust steam generated by the steam turbine 2 enters the compression heat pump 11, which converts the low-temperature heat of the exhaust steam into medium-temperature heat and transfers the medium-temperature heat to the user heating unit through heat exchange. The low-grade exhaust steam releases heat and becomes condensed water, which then flows into the economizer 5. The compression heat pump 11 can be a single-stage compression heat pump or a two-stage or multi-stage compression heat pump. The working medium used in the compression heat pump unit is preferably at least one of HFCs, HFOs, HCFOs, or a natural refrigerant.

[0030] In a further optimization scheme, the user heating unit includes a heat user 12 in communication with the compression heat pump 11, and a booster pump 13 is arranged between the compression heat pump 11 and the heat user 12. The booster pump 13 drives the water flow to circulate between the heat user 12 and the compression heat pump 11, thereby supplying heat to the heat user 12.

[0031] In a further optimization scheme, the cooling mechanism includes a condenser 3 in communication with the steam turbine 2, a second valve 17 is arranged between the condenser 3 and the steam turbine 2, and the condenser 3 is in communication with the economizer 5. The exhaust steam from the steam turbine 2 enters the condenser 3 and condenses into water, which then flows into the economizer 5.

[0032] In a further optimization scheme, the condenser 3 is provided with a heat dissipation circulation pipeline, one end of the heat dissipation circulation pipeline penetrates out of the condenser 3 and is in communication with the water inlet of the cooling tower 9, the other end of the heat dissipation circulation pipeline penetrates out of the condenser and is in communication with the water outlet of the circulating water pump 8, and the water inlet of the circulating water pump 8 is in communication with the water outlet of the cooling tower 9. The circulating water pump 8 drives the cooling liquid to circulate between the cooling tower 9 and the condenser 3, thereby continuously condensing the exhaust steam passing through the condenser 3.

[0033] In a further optimization scheme, the water outlet of the condenser 3 is in communication with a fourth valve 19, the water outlet of the fourth valve 19 is in communication with one of the water inlets of the second three-way valve 15, the water outlet of the compression heat pump 11 is in communication with a third valve 18, the third valve 18 is in communication with the other water inlet of the second three-way valve 15, the water outlet of the second three-way valve 15 is in communication with a condensate pump 4, and the condensate pump 4 is in communication with the economizer 5.

[0034] The condensed water from the condenser 3 and the condensed water from the compression heat pump 11 converge at the second three-way valve 15, and then flow into the economizer 5 under the action of the condensate pump 4.

[0035] In a further optimization scheme, the air inlet of the first heat exchange box is in communication with the flue gas outlet of the gas turbine 1, and the air outlet of the first heat exchange box is in communication with a chimney 10. The flue gas generated by the gas turbine 1 passes through the first heat exchange box and is discharged from the chimney 10.

[0036] Further optimization scheme, the steam turbine 2 outlet is communicated with the first three-way 14 inlet, the first three-way 14 two outlets are communicated with the first valve 16 and the second valve 17 respectively.

[0037] The outlet of the first three-way 14 is communicated with the first valve 16 and the second valve 17, the first valve 16 is communicated with the compression heat pump 11, and the second valve 17 is communicated with the condenser 3, so as to adjust the amount of steam flowing into the compression heat pump 11 and the condenser 3.

[0038] The compression heat pump 11 described in the application can also be coupled with a coal-fired power generation unit, a solar thermal power generation unit and the like, can bear part or all of the condenser cooling load of various power systems, and can be used for regional heating.

[0039] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application.

[0040] The above-described embodiments are only preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A combined cycle gas and steam cogeneration system for providing heat, comprising: The application relates to a gas turbine (1) which is connected with a first heat exchange unit, the first heat exchange unit is connected with a steam turbine (2), the steam turbine (2) is connected with a second heat exchange unit and a cooling mechanism, the second heat exchange unit is connected with a user heat supply unit, a first valve (16) is arranged between the steam turbine (2) and the second heat exchange unit, a second valve (17) is arranged between the steam turbine (2) and the cooling mechanism, and the cooling mechanism and the second heat exchange unit are connected with the first heat exchange unit. The first heat exchange unit comprises a first heat exchange box which is connected with the gas turbine (1), a superheater (7), a steam generator (6) and a coal economizer (5) are arranged in the first heat exchange box, the outlet of the superheater (7) extends out of the first heat exchange box and is connected with the steam turbine (2), the inlet of the superheater (7) is connected with the outlet of the steam generator (6), the inlet of the steam generator (6) is connected with the outlet of the coal economizer (5), and the inlet of the coal economizer (5) is connected with the cooling mechanism and the second heat exchange unit. The second heat exchange unit comprises a compression heat pump (11) which is connected with the steam turbine (2), the first valve (16) is arranged between the steam turbine (2) and the compression heat pump (11), and the outlet of the compression heat pump (11) is connected with the inlet of the coal economizer (5). The user heat supply unit comprises a heat user (12) which is connected with the compression heat pump (11), and a booster pump (13) is arranged between the compression heat pump (11) and the heat user (12). The cooling mechanism comprises a condenser (3) which is connected with the steam turbine (2), the second valve (17) is arranged between the condenser (3) and the steam turbine (2), and the condenser (3) is connected with the coal economizer (5). The condenser (3) is provided with a heat dissipation circulating pipeline, one end of the heat dissipation circulating pipeline extends out of the condenser (3) and is connected with the water inlet of a cooling tower (9), the other end of the heat dissipation circulating pipeline extends out of the condenser and is connected with the water outlet of a circulating water pump (8), and the water inlet of the circulating water pump (8) is connected with the water outlet of the cooling tower (9). The water outlet of the condenser (3) is connected with a fourth valve (19), the water outlet of the fourth valve (19) is connected with one water inlet of a second three-way pipe (15), the water outlet of the compression heat pump (11) is connected with a third valve (18), the third valve (18) is connected with the other water inlet of the second three-way pipe (15), the water outlet of the second three-way pipe (15) is connected with a condensate pump (4), and the condensate pump (4) is connected with the coal economizer (5). The gas inlet of the first heat exchange box is connected with the flue gas outlet of the gas turbine (1), and the gas outlet of the first heat exchange box is connected with a chimney (10). ​ The steam turbine (2) is connected with the inlet of a first three-way valve (14), and the two outlets of the first three-way valve (14) are connected with the first valve (16) and the second valve (17) respectively.

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