KR101343007B1 - Combined heat and power plant system - Google Patents

Abstract

Disclosed is a cogeneration system capable of producing warm water with the desired temperature by increasing the efficiency of a warm water converter by generating power by operating a steam turbine by using superheated steam and then providing, for the warm water heat exchanger, the converted superheated steam discharged from the steam turbine into saturated steam. The cogeneration system includes: a steam turbine operating a generator by using the superheated steam introduced from a high pressure header; a superheating reducer converting the superheated steam introduced from the steam turbine into the saturated steam; and a warm water heat exchanger producing warm water through the heat-exchange with the saturated steam introduced from the superheating reducer. [Reference numerals] (11) High pressure header;(12) Steam turbine;(13) Generator;(14) Superheating reducer;(15) Warm water heat exchanger;(16) Condensate water tank;(18) Deaerator;(19) Low pressure steam condenser;(21) District heating;(AA,BB) Superheated steam;(CC) Saturated steam;(DD) Supplying warm water;(EE) Recovering warm water

Description

Cogeneration System {COMBINED HEAT AND POWER PLANT SYSTEM}

The present invention relates to a cogeneration system, and more particularly, by using a superheated steam to operate the steam turbine to produce power, convert the superheated steam discharged from the steam turbine into saturated steam to provide a hot water heat exchanger The present invention relates to a cogeneration system capable of improving efficiency to produce hot water at a desired temperature.

In general, a cogeneration system is a power generation system capable of simultaneously generating power and supplying heat to increase overall energy utilization. For example, a cogeneration system generates power by driving a generator using a steam turbine, and is discharged from a steam turbine. It is a system that produces hot water using steam and supplies it to district heating.

In the conventional cogeneration system, electric power is produced by providing superheated steam to a steam turbine to produce electric power, and hot water is provided to a hot water heat exchanger to discharge hot water from the steam turbine to produce hot water. The conventional cogeneration system has a problem in that it is difficult to produce hot water produced at a hot water heat exchanger at a sufficiently high temperature by providing hot water by providing superheated steam to the hot water heat exchanger.

In other words, the superheated steam has a high enthalpy but has a gas-like property, which makes it difficult to use latent heat because condensation does not occur well. Therefore, the superheated steam is provided to a hot water heat exchanger using steam. It lowers the efficiency of the hot water heat exchanger, making it difficult to produce hot water at a sufficiently high temperature.

For example, in a conventional cogeneration system, when the hot water heat exchanger is capable of producing hot water of 105 ° C. under operating conditions where the pressure and temperature of superheated steam discharged from the steam turbine are 0.3 kg / cm 2 and 107 ° C., respectively, Even if the pressure and temperature of the superheated steam discharged are raised to 0.7 kg / cm 2 or more and 127 ° C., respectively, it is impossible to produce hot water at 115 ° C. to 120 ° C. required by district heating.

The present invention has been proposed to solve the problems of the conventional cogeneration system as described above, by converting the superheated steam discharged from the steam turbine into saturated steam to provide a hot water heat exchanger to improve the efficiency of the hot water heat exchanger hot water at a desired temperature To provide a cogeneration system that can produce the technical problem to be solved.

According to an aspect of the present invention,

A steam turbine operating the generator using superheated steam introduced from the high pressure header;

An overheat reducer for converting superheated steam introduced from the steam turbine into saturated steam; And

Hot water heat exchanger that produces hot water through heat exchange with saturated steam introduced from the superheat reducer

It provides a cogeneration system comprising a.

One embodiment of the present invention may further include a condensate tank for receiving excess steam in the hot water heat exchanger and storing it as condensate.

In addition, one embodiment of the present invention may further include a low pressure steam condenser provided to the hot water heat exchanger of the superheated steam discharged from the steam turbine to condense and reduce the remaining steam to water. In this embodiment, the water reduced by the low pressure steam condenser may be stored in the condensate tank.

In one embodiment of the present invention, the superheat reducer may convert the superheated steam discharged from the steam turbine into saturated steam by receiving water stored in the condensate tank and spraying the superheated steam discharged from the steam turbine.

In one embodiment of the present invention, the overheat reducer, the temperature detection unit for detecting the temperature of the water provided from the condensate tank; A valve providing / blocking superheated steam from the high pressure header; A control unit controlling opening and closing of the valve according to the temperature of the water detected by the temperature detecting unit; A heat exchanger configured to adjust a temperature of water through heat exchange between superheated steam provided according to opening and closing control of the valve by the controller and water provided from the condensate tank; And an injection unit for injecting water whose temperature is adjusted in the heat exchanger to superheated steam discharged from the steam turbine.

According to the present invention, by converting the superheated steam provided from the steam turbine to the hot water heat exchanger into saturated steam using the condensed water provided in the cogeneration system, it is possible to improve the efficiency of the hot water heat exchanger to produce hot water of high temperature.

1 is a configuration diagram of a cogeneration system according to an embodiment of the present invention.
2 is a detailed configuration diagram showing an example of an overheat reducer applied to a cogeneration system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. In addition, in describing the present invention, the defined terms are defined in consideration of the functions of the present invention, and they may be changed depending on the intention or custom of the technician working in the field, so that the technical components of the present invention are limited It will not be understood as meaning.

1 is a configuration diagram of a cogeneration system according to an embodiment of the present invention.

Referring to FIG. 1, a cogeneration system according to an embodiment of the present invention includes a steam turbine 12 and a steam turbine 12 that receive high pressure steam from a high pressure header 11 and operate a generator 13. It may include a superheat reducer 14 for converting the discharged steam from superheated steam to saturated steam and a hot water heat exchanger 15 for producing hot water through heat exchange using saturated steam.

In addition, one embodiment of the present invention, the condensate tank 16 for receiving excess steam in the hot water heat exchanger 15 is reduced to the water and stored, and condensed part of the steam discharged from the steam turbine 12 It may further include a low pressure steam condenser 19 to produce.

The embodiment illustrated in FIG. 1 selectively shows components related to the main features of the present invention. In the cogeneration system, which is actually implemented, various types of valves or sensors may be used as necessary to connect piping between the components. It may be provided. In Figure 1 it is to be noted that in order to more clearly and concisely describe the main technical idea of the present invention, the illustration of a valve or sensor that is not related to the features of the present invention is omitted.

The steam turbine 12 may be supplied with high-pressure superheated steam from the high-pressure header 11 to operate the generator 13 to produce power, and discharge the superheated steam used to operate the generator 13 again to generate a region. It may be provided to the hot water heat exchanger 15 for generating hot water supplied to the heating unit 21.

Superheated steam may be produced by raising the temperature of steam generated by a waste heat boiler (not shown) operating using an array generated in an incineration plant using a superheater (not shown), and the superheated steam generated by the superheater. May be collected by the high pressure header 11 and supplied to the steam turbine 12. For example, the pressure and temperature of the steam produced by the waste heat boiler may be about 40 kg / cm 2 and about 250.69 ° C., respectively, and the pressure and temperature of the superheated steam exiting the superheater may be about 40 kg / cm 2 and about 350, respectively. It may be a ℃, superheated steam discharged from the superheater may be provided to the steam turbine 12 through the high pressure header (11). In addition, the pressure and temperature of the superheated steam discharged from the steam turbine 12 after the generator 13 is operated may be about 0.3 kg / cm 2 and about 107 ° C., respectively.

The superheat reducer 14 is installed in a steam pipe between the steam turbine 12 and the hot water heat exchanger 15 to convert the superheated steam discharged from the steam turbine 12 into saturated steam, and then the hot water heat exchanger 15. To provide. In addition, the overheat reducer 14 may maintain the pressure and temperature of the saturated steam provided to the hot water heat exchanger 15 to conditions necessary for proper hot water production.

In one embodiment of the invention, the superheat reducer 14 saturates the superheated steam by injecting water at a predetermined temperature into the steam piping in which steam discharged from the steam turbine 12 is provided to the hot water heat exchanger 15. Can be converted to As shown in FIG. 1, the superheat reducer 14 may be provided with water for injection into a steam pipe from a condensate tank 16 provided in a cogeneration system.

In general, hot water heat exchangers are equipment for producing hot water through heat exchange between steam and water using latent heat of steam. In order to use the latent heat of steam, steam condensation must occur and saturated steam is required to condense steam.

Superheated steam, on the other hand, is used not only to prevent condensate from forming during long distance steam transport but also to prevent condensation on the blades of the steam turbine. Condensation on the blades of the steam turbine causes severe vibration and scale on the blade surface, which can damage the blades of the steam turbine. Therefore, superheated steam is used to operate the steam turbine.

However, superheated steam having a high superheat has high enthalpy but has a gas-like property, making it difficult to use latent heat. In addition, the superheated steam also significantly lowers the heat transfer coefficient, thereby greatly reducing the efficiency of the hot water heat exchanger.

Therefore, in a cogeneration system in which a steam turbine is operated to generate power and the steam discharged from the steam turbine is used again to produce hot water, converting the superheated steam used in the operation of the steam turbine to saturated steam is an efficiency of the hot water heat exchanger. Is necessary to improve.

As in the present invention, when the water is injected to the superheated steam discharged from the steam turbine (12 of FIG. 1) using the superheat reducer 14, the injected water is evaporated and the superheated steam is superheated and saturated steam Can be converted to

2 is a detailed block diagram showing an example of the overheat reducer applied to the cogeneration system according to the embodiment of the present invention in more detail.

Referring to FIG. 2, the overheat reducer 14 provides a temperature detector 141 for detecting a temperature of water provided from the condensate tank 16 (FIG. 1) and a superheated steam from a high pressure header (11 in FIG. 1). To the opening and closing control of the valve 143 and the control unit 142 that controls the opening and closing of the valve 143 according to the temperature of the water detected by the temperature detecting unit 141. The heat-regulated water in the heat exchanger 144 and the heat exchanger 144 which adjust the temperature of the water through heat exchange of the water provided from the superheated steam provided by the condensate tank 16 of FIG. 1 and the steam turbine 12 of FIG. It may include an injection unit 145 for injecting the superheated steam discharged from).

The temperature detector 141 may detect the temperature of the water provided to the overheat reducer 14 by the pump 17 in the condensate tank 16 (FIG. 1). The temperature detector 141 detects the temperature of the water flowing from the condensate tank 16 (FIG. 1) in order to maintain a constant temperature of the water injected in the process of converting the superheated steam into saturated steam. Information about the detected temperature of the water is provided to the controller 142, which controls the opening and closing of the valve 143 which provides superheated steam in the high pressure header (11 in FIG. 1) to maintain the water temperature at a preset temperature. Can be adjusted.

The valve 143 may be installed in a steam pipe between the high pressure header 11 of FIG. 1 and the heat exchanger 144 to provide or block superheated steam from the high pressure header to the heat exchanger 144. The valve 143 may be opened or closed or controlled by the control of the control unit 142.

The control unit 142 is provided with the temperature of the water detected by the temperature detector 141 to control the opening or closing of the valve 143 or the amount of opening and closing to provide the heat exchanger 144 from the high-pressure header (11 in Figure 1) The amount of steam can be controlled. The control unit 142 may store a look-up table in which the valve 143 is opened or closed, the opening / closing time, or the opening / closing amount according to the temperature of the water detected by the temperature detecting unit 141. By controlling the amount of superheated steam provided to the heat exchange unit 144 from 11) it is possible to control the temperature of the water injected to a predetermined appropriate temperature.

The heat exchanger 144 may raise the temperature of the water to a predetermined temperature through heat exchange between the water provided in the condensate tank 16 of FIG. 1 and the superheated steam provided from the high pressure header 11 of FIG. 1.

The injector 145 is a device capable of injecting water, and receives a water whose temperature is appropriately adjusted in the heat exchanger 144 and receives a steam turbine (12 of FIG. 1) and a hot water heat exchanger (15 of FIG. 1). By injecting into the steam pipe connected therebetween, the superheated steam discharged from the steam turbine (12 of FIG. 1) can be converted into saturated steam and provided to the hot water heat exchanger 15.

Referring back to FIG. 1, the hot water heat exchanger 15 may be provided with saturated steam provided by the overheat reducer 14 to produce hot water by heat exchange. In other words, the temperature of the water may be increased by using latent heat by condensation of saturated steam provided by the overheat reducer 14, and hot water having the elevated temperature may be provided to the local heating unit 21 as heating water. The hot water provided to the district heating unit 21 may be recovered to the hot water heat exchanger 15 again.

For example, the pressure and temperature of the saturated steam provided to the hot water heat exchanger 15 may be about 1.5 kg / cm 2 and about 127 ° C., respectively, and are generated by heat exchange with the saturated steam to generate a local heating unit ( The temperature of the hot water provided to the 21) may be about 115 ℃ to 120 ℃, the temperature of the hot water recovered from the district heating unit 21 may be about 90 ℃.

Meanwhile, one embodiment of the present invention may further include a condensate tank 16 for storing condensate. As described above, the condensate tank 16 may provide the stored condensate to the superheat reducer 14. The condensate tank 16 may store condensate generated by condensation of steam generated in the heat exchange process of the hot water heat exchanger 15.

In addition, an embodiment of the present invention, the low pressure steam condenser 19 is connected to the rear end of the steam turbine 12 is provided to the hot water heat exchanger of the superheated steam discharged from the steam turbine 120 to condense and reduce the remaining steam to water (19) ) May be further included, and the water reduced in the low pressure steam condenser 19 may be stored in the aforementioned condensate tank 16.

The water stored in the condensate tank 16 is provided by the pump 17 to the superheat reducer 14, some of which are described above, and to the degasser 18, to remove gases such as oxygen dissolved in the water. It may then be provided as a waste heat boiler (not shown).

Table 1 below is a table comparing the performance of a hot water heat exchanger of a conventional cogeneration system employing an overheat reducer and a cogeneration system employing an overheat reducer according to an embodiment of the present invention.

Steam Turbine Exit Hot water heat exchanger hot water pressure Temperature Inlet pressure Inlet temperature Supply temperature Recovery temperature No overheating reducer 0.41 128.26 0.29 120.88 108.56 80.63 0.40 127.53 0.28 120.93 108.61 79.84 0.41 127.47 0.30 121.21 108.70 78.60 Overheat reducer application 0.8 145.55 0.68 122.84 115.86 77.80 0.8 151.00 0.78 127.11 117.31 76.73

As shown in Table 1, when the overheat reducer is not applied, the supply temperature of the hot water produced by the hot water heat exchanger 15 is about 108 ° C, which is about 115 ° C to 120 ° C which is the temperature of hot water required for normal district heating. It did not meet the conditions of ° C. In contrast, the cogeneration system employing the overheat reducer according to an embodiment of the present invention having an inlet pressure and inlet temperature conditions similar to the case of not applying the overheat reducer, the local heating of the hot water supply temperature to about 115 ° C or about 117 ° C. It can be confirmed that the hot water temperature requirements required by the company can be met.

Thus, one embodiment of the present invention, by using the condensed water provided in the cogeneration system to convert the superheated steam provided from the steam turbine to the hot water heat exchanger to saturated steam to improve the efficiency of the hot water heat exchanger to produce hot water of high temperature Can be.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited to the embodiments described, but should be determined by the scope of the following claims and equivalents thereof.

11: high pressure header 12: steam turbine
13: generator 14: overheat reducer
15: hot water heat exchanger 16: condensate tank
17: pump 18: deaerator
19: low pressure steam condenser 21: district heating unit
141: temperature detector 142: controller
143: valve 144: heat exchanger
145: spray part

Claims (5)

A steam turbine operating the generator using superheated steam introduced from the high pressure header;
An overheat reducer for converting superheated steam introduced from the steam turbine into saturated steam;
A hot water heat exchanger producing hot water through heat exchange with saturated steam introduced from the superheat reducer; And
It includes a condensate tank for receiving excess steam in the hot water heat exchanger to store as condensate,
And the superheat reducer receives water stored in the condensate tank and injects the superheated steam discharged from the steam turbine to convert the superheated steam discharged from the steam turbine into saturated steam. delete The method of claim 1,
It further comprises a low pressure steam condenser provided to the hot water heat exchanger of the superheated steam discharged from the steam turbine to condense and reduce the remaining steam to water,
And the water reduced by the low pressure steam condenser is stored in the condensate tank. delete The overheat reducer according to claim 1 or 3,
A temperature detector detecting a temperature of water provided from the condensate tank;
A valve providing or blocking superheated steam from the high pressure header;
A control unit controlling opening and closing of the valve according to the temperature of the water detected by the temperature detecting unit;
A heat exchanger configured to adjust a temperature of water through heat exchange between superheated steam provided according to opening and closing control of the valve by the controller and water provided from the condensate tank; And
And a spraying unit for spraying the water whose temperature is adjusted in the heat exchanger to the superheated steam discharged from the steam turbine.

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