Sealing gas supply apparatus

Disclosed herein is a sealing gas supply apparatus. In the sealing gas supply apparatus for supplying sealing gas to a turbomachine of a power generation system, a source comprises at least one low-temperature source for supplying a working fluid to the sealing gas supply apparatus and at least one high-temperature source for supplying a working fluid having a higher temperature than the low-temperature source to the sealing gas supply apparatus, and the working fluids are mixed in the sealing gas supply apparatus to be suitable for a sealing condition as a temperature condition required in a sealing system so as to be supplied to the sealing system of the turbomachine. In accordance with the present disclosure, since separate electric power is not consumed during normal operation by improving a turbine sealing gas source, it is possible to enhance power generation performance by a reduction in power consumption.

CROSS-REFERENCE(S) TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No. 10-2017-0034737, filed on Mar. 20, 2017, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

Exemplary embodiments of the present disclosure relate to a sealing gas supply apparatus.

Description of the Related Art

Internationally, the need to efficiently produce electric power has gradually increased, and various efforts have been made to reduce generation of pollutants and to increase power production since activities for reducing generation of pollutants are gradually increasing. As a part of these efforts, power generation systems using supercritical carbon dioxide (CO2), which utilize supercritical carbon dioxide as a working fluid, have been actively researched and developed.

Since supercritical carbon dioxide has a density similar to that of liquid as well as a viscosity similar to that of gas, it is possible to reduce the size of devices and to minimize the consumption of electric power required for compression and circulation of fluid. In addition, supercritical carbon dioxide has an advantage in that it is easy to handle supercritical carbon dioxide since it has a lower critical point of 31.4° C. and 72.8 atmospheres, compared to water having the critical point of 373.95° C. and 217.7 atmospheres. When such a power generation system using supercritical carbon dioxide is operated at the temperature of 550° C., the system has a net power generation efficiency of about 45%. In addition, the power generation system is advantageous in that it is possible to improve its power generation efficiency by more than 20%, compared to an existing steam cycle, and to reduce the size of a turbomachine of the system.

The power generation system using supercritical carbon dioxide generally forms a closed cycle, in which the carbon dioxide used for power generation is not discharged to outside, and the system uses supercritical carbon dioxide as a working fluid.

The working fluid supplied into a power generation cycle of the system serves two purposes of driving the turbomachine and of bearing lubrication and sealing of the turbomachine. An example method of supplying a working fluid is disclosed in U.S. Pat. No. 8,281,593.

SUMMARY OF THE DISCLOSURE

The high-pressure working fluid used to seal the turbomachine is typically heated and supplied to the sealing system of the turbomachine by a dry gas seal conditioner. For the heating of the working fluid, 1 to 3% of electric power produced in the power generation cycle is used according to the size of the dry gas seal conditioner. For instance, electric power of 40 to 80 kW is consumed for a 1.5 to 5 MW conditioner. Accordingly, since the use of such power causes a reduction of power generation efficiency in terms of the total efficiency of the power generation cycle, it may be necessary to resolve this issue.

An object of the present disclosure is to provide a sealing gas supply apparatus capable of enhancing power generation performance by improving a turbine sealing gas source.

In accordance with one aspect of the present disclosure, a sealing gas supply apparatus supplies sealing gas to a turbomachine of a power generation system, wherein a source comprises at least one low-temperature source for supplying a working fluid to the sealing gas supply apparatus and at least one high-temperature source for supplying a working fluid having a higher temperature than the low-temperature source to the sealing gas supply apparatus, and the working fluids are mixed in the sealing gas supply apparatus to be suitable for a sealing condition as a temperature condition required in a sealing system so as to be supplied to the sealing system of the turbomachine.

The low-temperature source may be a working fluid supply pump, which is connected to a storage tank storing the working fluid, or a main pump of the power generation system, and the high-temperature source may be a turbine inlet or recuperator outlet of the power generation system.

The sealing gas supply apparatus may comprise a heat exchanger for heating the working fluid supplied from the low-temperature source, and a cooling fan for cooling the working fluid supplied from the high-temperature source.

The heat exchanger and the cooling fan may be operated only in case of startup or emergency of the power generation system.

The sealing gas supply apparatus may comprise a first valve installed in a working fluid transfer pipe connected to the low-temperature source, a heat exchanger through which the working fluid passing through the first valve passes, and a control valve for controlling a flow rate of the working fluid passing through the heat exchanger and the first valve.

The sealing gas supply apparatus may comprise a fourth valve installed in a working fluid transfer pipe connected to the high-temperature source, a cooling fan through which the working fluid passing through the fourth valve passes, and a control valve for controlling a flow rate of the working fluid passing through the cooling fan and the fourth valve.

The working fluids passing through the respective control valves may be mixed suitably for the sealing condition to be supplied to the sealing system.

The sealing gas supply apparatus may comprise a first valve installed in a working fluid transfer pipe connected to the low-temperature source, a fourth valve installed in a working fluid transfer pipe connected to the high-temperature source, a heat exchanger through which the working fluid mixed through the first and fourth valves passes, a cooling fan through which the working fluid passing through the heat exchanger passes, a first control valve for controlling a flow rate of the working fluid branched from an inlet of the heat exchanger, and a third control valve for controlling a flow rate of the working fluid passing through the cooling fan, wherein the working fluids passing through the first and third control valves may be mixed suitably for the sealing condition to be supplied to the sealing system.

The sealing gas supply apparatus may comprise a first valve installed in a working fluid transfer pipe connected to the low-temperature source, a fourth valve installed in a working fluid transfer pipe connected to the high-temperature source, a heat exchanger through which the working fluid mixed through the first and fourth valves passes, a cooling fan through which the working fluid passing through the heat exchanger passes, a second control valve disposed at an outlet of the heat exchanger, a fourth control valve disposed at an outlet of the cooling fan, a first control valve for controlling a flow rate of the working fluid branched from an inlet of the heat exchanger, and a third control valve for controlling a flow rate of the working fluid branched from an inlet of the cooling fan.

The working fluid passing through the first control valve may join at an outlet of the second control valve, and the working fluid passing through the third control valve may join at an outlet of the fourth control valve.

In accordance with another aspect of the present disclosure, a sealing gas supply apparatus supplies sealing gas to a turbomachine, wherein a source comprises a plurality of low-temperature sources for supplying working fluids to the sealing gas supply apparatus and a plurality of high-temperature sources for supplying working fluids having a higher temperature than the low-temperature sources to the sealing gas supply apparatus, and the working fluids supplied from the low-temperature sources are heated and the working fluids supplied from the high-temperature sources are cooled so that the working fluids are mixed suitably for a sealing condition as a temperature condition required in a sealing system of the turbomachine and then supplied to the sealing system.

The low-temperature sources may be a working fluid supply pump, which is connected to a storage tank storing the working fluid, and a main pump of a power generation cycle, and the high-temperature sources may be a turbine inlet and recuperator outlet of the power generation cycle.

The sealing gas supply apparatus may comprise a heat exchanger for heating the working fluids supplied from the low-temperature sources, and a cooling fan for cooling the working fluids supplied from the high-temperature sources.

The heat exchanger and the cooling fan may be operated only in case of startup or emergency of the power generation cycle.

The sealing gas supply apparatus may comprise first and second valves installed in respective working fluid transfer pipes connected to the low-temperature sources, a heat exchanger through which a portion of the working fluids passing through the first and second valves passes, and control valves for respectively controlling a flow rate of the working fluid passing through the heat exchanger and a flow rate of the working fluid which does not pass through the heat exchanger.

The sealing gas supply apparatus may comprise third and fourth valves installed in respective working fluid transfer pipes connected to the high-temperature sources, a cooling fan through which a portion of the working fluids passing through the third and fourth valves passes, and control valves for respectively controlling a flow rate of the working fluid passing through the cooling fan and a flow rate of the working fluid which does not pass through the cooling fan.

The working fluids passing through the respective control valves may be mixed suitably for the sealing condition to be supplied to the sealing system.

The sealing gas supply apparatus may comprise first and second valves installed in respective working fluid transfer pipes connected to the low-temperature sources, third and fourth valves installed in respective working fluid transfer pipes connected to the high-temperature sources, a heat exchanger through which the working fluids passing through the first and second valves pass, a first control valve disposed at an outlet of the heat exchanger to control a flow rate of the working fluid passing through the heat exchanger, a cooling fan through which the working fluids passing through the third and fourth valves pass, and a third control valve disposed at an outlet of the cooling fan to control a flow rate of the working fluid passing through the cooling fan.

The working fluids passing through the first and third control valves may be mixed suitably for the sealing condition to be supplied to the sealing system.

The sealing gas supply apparatus may comprise first and second valves installed in respective working fluid transfer pipes connected to the low-temperature sources, third and fourth valves installed in respective working fluid transfer pipes connected to the high-temperature sources, a heat exchanger through which the working fluids passing through the first to fourth valves pass, a cooling fan installed at an outlet of the heat exchanger, and a third control valve installed at an outlet of the cooling fan to control a flow rate of the working fluid passing through the cooling fan.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. The present disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present disclosure.

Hereinafter, a sealing gas supply apparatus according to various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

The power generation system using supercritical carbon dioxide used herein according to various embodiments of the present disclosure includes a system, where most of working fluids are supercritical fluids and the remainder is a subcritical fluid as well as a system where all working fluids flowing in a cycle are supercritical fluids.

In addition, carbon dioxide is used as a working fluid in various embodiment of the present disclosure. The term “carbon dioxide” used herein includes pure carbon dioxide in a chemical sense, carbon dioxide with few impurities in a general sense, and carbon dioxide mixed with one or more fluids as additives. Similarly, the sealing gas to be described below also includes the above conditions.

The working fluid is supplied into the power generation system using supercritical carbon dioxide for a turbomachine and for production of electric power in the power generation system using supercritical carbon dioxide.

The working fluid is supplied to a bearing system of the turbomachine for use to lubricate each component of the turbomachine, and it is supplied to a sealing system of the turbomachine to seal the turbomachine.

The high-pressure working fluid for sealing is typically heated and supplied to the sealing system of the turbomachine by a dry gas seal conditioner.

Working fluids are introduced into the dry gas seal conditioner through two paths from a main pump for working fluid and a working fluid supply pump connected to a storage tank storing the working fluids. For example, working fluids having a temperature of about −20° C. to 40° C. may be supplied through the two paths, where the temperature of the working fluid in the storage tank may range from −60° C. to 50° C., whereas the temperature of the working fluid at the rear end of the supply pump may range from −50° C. to 100° C. In addition, the working fluid may be heated to a temperature of about 90° C.±10° C. in the dry gas seal conditioner and then be supplied to the turbomachine. It is appreciated that the above temperature condition is illustrated by way of example, and the temperature required for the turbomachine, such as 100° C., 200° C., or 300° C., may be varied according to the design choice of the turbomachine. In addition, since the working fluids are continuously heated in the dry gas seal conditioner, electric power is continuously consumed.

FIG. 1is a diagram illustrating a sealing gas supply apparatus100according to a first embodiment of the present disclosure.FIG. 2is a diagram illustrating a first example of the structure of the sealing gas supply apparatus100ofFIG. 1.

As illustrated inFIG. 1, in the sealing gas supply apparatus100according to the first embodiment of the present disclosure, working fluids are supplied to the sealing gas supply apparatus100through the total of four paths under different temperature conditions. For the sake of convenience, the sealing gas before introduction to the sealing gas supply apparatus100is defined as a “working fluid,” whereas the sealing gas supplied to a turbomachine after passing through the sealing gas supply apparatus100is defined as “sealing gas”.

In a first path, the working fluid is introduced from a working fluid supply pump10, which is connected a storage tank storing the working fluid, into the sealing gas supply apparatus100under a first temperature condition. The first temperature condition may range from −20° C. to 40° C.

In a second path, a working fluid is introduced from a main pump20of a power generation cycle into the sealing gas supply apparatus100under a second temperature condition. The second temperature condition may range from −20° C. to 40° C.

In a third path, a working fluid is introduced from a turbine inlet30of the power generation cycle into the sealing gas supply apparatus100under a third temperature condition. The third temperature condition may range from 250° C. to 400° C.

In a fourth path, a working fluid is introduced from a recuperator outlet40of the power generation cycle into the sealing gas supply apparatus100under a fourth temperature condition. The fourth temperature condition may range from 100° C. to 250° C.

The working fluid supply pump and the main pump in the first and second paths serve as working fluid sources having a relatively low temperature, compared to the turbine inlet and the recuperator outlet in the third and fourth paths. Therefore, it may be possible to set the sealing gas to a desired temperature by mixing a working fluid having a relatively low temperature with a working fluid having a high temperature.

In more detail, the working fluids are supplied to the sealing gas supply apparatus100under the first to fourth temperature conditions, and the sealing gas supplied to a sealing system50of the turbomachine controls the flow rate of the working fluid for each introduction path in the sealing gas supply apparatus100to have a temperature suitable for a sealing condition. The sealing condition may be in a temperature range of 90° C.±10° C. suitable for the sealing system50.

To control the flow rate of the working fluid for each supply path, the sealing gas supply apparatus100comprises a first valve112that is installed in a working fluid transfer pipe in the first path, a second valve114that is installed in a working fluid transfer pipe in the second path, a third valve116that is installed in a working fluid transfer pipe in the third path, and a fourth valve118that is installed in a working fluid transfer pipe in the fourth path.

The working fluid exiting the first valve112passes through a heat exchanger120and a first control valve152, and the working fluid exiting the second valve114passes through a second control valve154. The working fluid exiting the third valve116passes through a cooling fan140and a third control valve156, and the working fluid exiting the fourth valve118passes through a fourth control valve158. The working fluids having passed through the first to fourth control valves152to158are mixed suitably for the sealing condition and then supplied from the sealing gas supply apparatus100to the sealing system50.

The first to fourth valves112to118are provided to control the flow rates of the working fluids introduced into the sealing gas supply apparatus100to block the working fluids. The first to fourth control valves152to158are also provided to control the flow rates of the working fluids so as to be suitable for the sealing condition. The heat exchanger120is a heater that consumes electric power, and the cooling fan140also consumes electric power. The heat exchanger120and the cooling fan140are arranged in parallel.

In case of a startup or emergency of a power generation cycle, it may be possible to heat or cool the working fluid for each introduction path by supplying electric power to the heat exchanger120or the cooling fan140. Otherwise, it is possible to control the temperature of sealing gas discharged from the sealing gas supply apparatus100so as to be suitable for the sealing condition by controlling the flow rates of the working fluids using the first to fourth control valves152to158without separately heating the working fluids. That is, during the normal operation, the working fluid merely passes through the heat exchanger120or the cooling fan140without heating or cooling therein, where this is being commonly applied to the various embodiments of the present disclosure.

Accordingly, the present disclosure is advantageous in that the electric power of the power generation system is consumed only in case of startup or emergency of the power generation cycle, whereas the electric power is not separately or additionally consumed during its normal operation. When the sealing gas supply apparatus100is operated under this condition, it may be possible to reduce the electric energy required to operate the sealing gas supply apparatus100by about 0.1 to 0.4%. As a result, it may be possible to enhance the performance of the power generation system by about 1 to 2.5% of electric power produced therein.

Besides, it may be possible to match the sealing gas for the sealing condition without additional power consumption by configuring the sealing gas supply apparatus100as follows.

FIG. 3is a diagram illustrating a second example of the structure of the sealing gas supply apparatus according toFIG. 1.

As illustrated inFIG. 3, the sealing gas supply apparatus100′ comprise first to fourth valves112′ to118′, a heat exchanger120′, a cooling fan140′, a first control valve152′, and a third control valve156′. The sealing gas supply apparatus100′ may form a path, in which the working fluids having passed through or exiting the first and second valves112′ and114′ are mixed and pass through the heat exchanger120′ and the first control valve152′ as well as a path in which the working fluids having passed through or exiting the third and fourth valves116′ and118′ are mixed and pass through the cooling fan140′ and the third control valve156′. Then, the working fluids flowing through the two paths are mixed so that the sealing gas is suitable for a sealing condition. The heat exchanger120′ is a heater that consumes electric power, and the cooling fan140′ also consumes electric power. The heat exchanger120′ and the cooling fan140′ are arranged in parallel.

FIG. 4is a diagram illustrating a third example of the structure of the sealing gas supply apparatus100ofFIG. 1.

In this example, the sealing gas supply apparatus100″ comprises first to fourth valves112″ to118″, a heat exchanger120″, a cooling fan140″, and a third control valve156″. The sealing gas supply apparatus100″ may form a path, in which the working fluids having passed through the first to fourth valves112″ to118″ are mixed and sequentially pass through the heat exchanger120″ and the cooling fan140″. The sealing gas having passed through the third control valve156″ may be discharged suitably for a sealing condition. To this end, the heat exchanger120″ and the cooling fan140″ are arranged in sequence.

In the sealing gas supply apparatus according to the second and third examples of the first embodiment, the heat exchanger and the cooling fan consume electric power in case of a startup or emergency of the power generation cycle, whereas they do not consume separate electric power during its normal operation.

According to the second embodiment, the paths for the working fluids introduced into the sealing gas supply apparatus may be configured differently from the above examples of the first embodiment, where the detailed description of the same configuration as the above examples will be omitted.

FIG. 5is a diagram illustrating a sealing gas supply apparatus100aaccording to the second embodiment of the present disclosure.FIG. 6is a diagram illustrating a sealing gas supply apparatus100baccording to a third embodiment of the present disclosure.FIG. 7is a diagram illustrating a sealing gas supply apparatus100caccording to a fourth embodiment of the present disclosure.

As illustrated inFIG. 5, in the sealing gas supply apparatus100aaccording to the second embodiment of the present disclosure, working fluids are supplied to the sealing gas supply apparatus100athrough three paths each under different temperature conditions.

The three paths correspond to the first to third paths in the embodiment according toFIG. 1, and the working fluids may be supplied through the three paths under the first to third temperature conditions identical to those in the embodiment illustrated inFIG. 1.

As illustrated inFIG. 6, three paths correspond to the first, second, and fourth paths in the embodiment illustrated inFIG. 1, and working fluids may be supplied to the sealing gas supply apparatus100bthrough the three paths under the first, second, and fourth temperature conditions identical to those in the embodiment illustrated inFIG. 1.

As illustrated inFIG. 7, working fluids may be supplied to the sealing gas supply apparatus100cthrough two paths. In this case, the two paths correspond to the first and fourth paths in the embodiment illustrated inFIG. 1, and the working fluids are supplied to the sealing gas supply apparatus100cunder the first and fourth temperature conditions identical to those in the embodiment illustrated inFIG. 1.

That is, it may be possible to control a sealing gas to a temperature suitable for a sealing condition by mixing a low-temperature working fluid with a high-temperature working fluid using a working fluid source having a relatively low temperature and a working fluid source having a relatively high temperature together.

When a single low-temperature working fluid source and only a single high-temperature working fluid source are used, the sealing gas supply apparatus may be configured as follows.

FIG. 8is a diagram illustrating a first example of the structure of the sealing gas supply apparatus100cofFIG. 7.FIG. 9is a diagram illustrating a second example of the structure of the sealing gas supply apparatus100cofFIG. 7.FIG. 10is a diagram illustrating a third example of the structure of the sealing gas supply apparatus100cofFIG. 7.

As illustrated inFIG. 8, for the control of the flow rate of the working fluid for each supply path, the sealing gas supply apparatus100ccomprises a first valve112cthat is installed in a working fluid transfer pipe in the first path and a fourth valve118cthat is installed in a working fluid transfer pipe in the fourth path.

The working fluid having passed through the first valve112cis branched into two working fluids, where the sealing gas supply apparatus100cforms a path with one of the working fluids sequentially passing through a heat exchanger120cand a first control valve152cas well as a path with the other working fluid passing through a second control valve154c. The working fluid having passed through the fourth valve118cis also branched into two working fluids, where the sealing gas supply apparatus100cforms a path with one of the working fluids sequentially passing through a cooling fan140cand a third control valve156cas well as a path with the other working fluid passing through a fourth control valve158c. The working fluids having passed through the first to fourth control valves152cto158care mixed suitably for a sealing condition and then supplied from the sealing gas supply apparatus100cto the sealing system50.

As illustrated inFIG. 9, the sealing gas supply apparatus100c′ comprises a first valve112c′ and a fourth valve118c′, similarly to the example ofFIG. 8. The sealing gas supply apparatus100c′ may form a path in which the working fluids having passed through the respective first and fourth valves112c′ and118c′ are mixed and sequentially pass through a heat exchanger120c′ and a cooling fan140c′. A third control valve156c′ is provided at the outlet of the cooling fan140c′, where the sealing gas supply apparatus100c′ may form a path with the mixed working fluid partially branching from the inlet of the heat exchanger120c′ and then joining at the outlet of the third control valve156c′ after passing through a separate first control valve150c′. The working fluids having passed through the third control valve156c′ and the first control valve150c′ may be appropriately mixed and discharged suitably for a sealing condition.

As illustrated inFIG. 10, the sealing gas supply apparatus100c″ comprises a first valve112c″ and a fourth valve118c″, similarly to the example ofFIG. 8. The working fluids having passed through the respective first and fourth valves may be mixed and supplied to a heat exchanger120c″ and a cooling fan140c″.

The heat exchanger120c″ and the cooling fan140c″ are arranged in sequence, and a first control valve150c″ is installed at the outlet of the heat exchanger120c″ so that the working fluid sequentially passes through them. In this case, the sealing gas supply apparatus100c″ may form a path in which the working fluid is partially branched from the inlet of the heat exchanger120c″ and then joins at the outlet of the first control valve150c″. The working fluid joined with the working fluid having passed through the first control valve150c″ is branched so that a portion thereof flows to the cooling fan140c″ and the rest flows to a third control valve154c″. The cooling fan140c″ and a fourth control valve156c″ are arranged in sequence, where the sealing gas supply apparatus100c″ may form a path with the working fluid having passed through the third control valve154c″ joining with the working fluid having passed through the fourth control valve156c″ at the outlet of the fourth control valve156c″. The working fluid, which is finally joined and mixed, becomes sealing gas suitable for a sealing condition to be discharged from the sealing gas supply apparatus100c″.

As described above, since the low-temperature and high-temperature turbine sealing gas sources are used together, separate or additional electric power is not consumed during its routine or normal operation except for an emergency or start up. Therefore, it may be possible to significantly enhance power generation performance by reducing power consumption.

As is apparent from the above description, since a sealing gas supply apparatus according to exemplary embodiments of the present disclosure does not consume separate electric power during its normal operation by improving a turbine sealing gas source, it may be possible to enhance power generation performance by reducing power consumption.