US20150143808A1

US20150143808A1 - Hybrid turbine generation system

Info

Publication number: US20150143808A1
Application number: US14/264,780
Authority: US
Inventors: Yong Bok Lee; Se Na Jeong; Chang Ho Kim; Bok Seong CHOE
Original assignee: Korea Advanced Institute of Science and Technology KAIST
Current assignee: Korea Advanced Institute of Science and Technology KAIST
Priority date: 2013-11-28
Filing date: 2014-04-29
Publication date: 2015-05-28
Also published as: KR20150062027A

Abstract

The present disclosure provides a turbine generation system, including a first turbine part that is configured to have a first impeller rotated by an introduced fluid, and a second turbine part that is configured to have a second impeller rotated by steam, evaporated within a cycle unit, in which the fluid circulates along a rankine cycle, wherein the fluid, which is discharged from the first turbine part after rotating the first impeller, is heat-exchanged with a refrigerant of an evaporator disposed in the cycle unit.

Description

CROSS-REFERENCE TO RELATED APPLICATION

Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2013-0146530, filed on Nov. 28, 2013, the contents of which is incorporated by reference herein in its entirety.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure
This specification relates to a turbine generation system generating turbine power, and a method of increasing energy efficiency of the turbine generation system by using waste heat.
2. Background of the Disclosure
A waste heat generation is a type of generation method recycling waste heat, which has been discarded before, in such a manner of changing waste gas of high temperature (over 550° C.), which is generated from a power plant and a waste incineration facility, into steam of low temperature (below 250° C.) through a waste heat boiler, supplying the steam into a steam turbine to generate power, and generating electricity using the generated power. The waste heat generation is contributing to preventing emissions of air pollutants and improving efficiency of a generation system by reproducing waste heat resources into electric energy. However, as disclosed in Korean Laid-open Patent No. 10-2012-0035176, attempts have been made to apply other methods, not the steam turbine method, to a production of electric power using a small-scale of heat source.
This is because most of medium and small incineration facilities suffer from ensuring continuous, stable steam due to a lack of wastes transported, and considerable waste heat remains unused due to a lack of economic feasibility, such as difficulties in ensuring plumping system investment and finance. Also, the lifespan of a shaft bearing system is limited upon high-speed driving of the steam turbine under an environment of low temperature and low pressure, and application technologies verified for a waste heat recovery system, which is suitable for the medium and small incineration facilities, have not been sufficiently introduced.
However, if those drawbacks are overcome, the waste heat generation may be implemented by the steam turbine type as the already-verified generation method.

SUMMARY OF THE DISCLOSURE

Therefore, an aspect of the detailed description is to provide a turbine generation system, which is suitable for utilizing waste heat, and an operation method thereof.
Another aspect of the detailed description is to provide a turbine generation system with more improved energy efficiency.
To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a turbine generation system, including a first turbine part that is configured to have a first impeller rotated by an introduced fluid, and a second turbine part that is configured to have a second impeller rotated by steam, evaporated within a cycle unit, in which the fluid circulates along a rankine cycle. In the turbine generation system, the fluid, which is discharged from the first turbine part after rotating the first impeller, may be heat-exchanged with a refrigerant of an evaporator disposed in the cycle unit.
In accordance with one exemplary embodiment, a generator may be disposed between the first impeller and the second impeller. The generator may include a single rotating shaft having both ends coupled with the first impeller and the second impeller, respectively. The single rotating shaft may be supported by a foil bearing. The first impeller and the second impeller may have the same shape.
The foil bearing may include first and second foil bearings disposed with a predetermined spacing therebetween, and a stator made of a coil is located between the first and second foil bearings. A magnet may be disposed within the single rotating shaft.
In accordance with another exemplary embodiment, the turbine generation system may further include a burner connected to an introduction opening of the first turbine part, to heat the fluid introduced into the first turbine part.
In accordance with another exemplary embodiment, the cycle unit may include a condenser that is configured to condense the fluid evaporated in the evaporator, and the second turbine part may be disposed between the evaporator and the condenser.
In accordance with another exemplary embodiment, the rankine cycle may be an organic rankine cycle which receives thermal energy supplied from the fluid discharged from the first turbine part.
A heat exchanger may be disposed to be connected to the evaporator of the organic rankine cycle, and a refrigerant circulating along the heat exchanger and the evaporator may be heat-exchanged in the heat exchanger with the fluid discharged from the first turbine part.
The present disclosure may also provide a turbine generation system, including a first turbine part that is configured to have a first impeller rotated by an introduced fluid, and a second turbine part that is configured to have a second impeller rotated by steam, evaporated within a cycle unit, in which the fluid circulates along a rankine cycle, wherein the first impeller and the second impeller may be mounted to both ends of a single rotating shaft, respectively. The fluid, which is discharged from the first turbine part after rotating the first impeller, may be heat-exchanged with a refrigerant of an evaporator disposed in the cycle unit.
Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the disclosure.

In the drawings:

FIG. 1 is a conceptual view illustrating a double suction type turbo generator supported by a foil bearing;

FIG. 2 is a conceptual view of a hybrid turbo generator system according to the present disclosure, to which the turbo generator of FIG. 1 is applied; and

FIG. 3 is a T-s diagram of an organic rankine cycle using R-245fa.

DETAILED DESCRIPTION OF THE DISCLOSURE

Description will now be given in detail of a hybrid turbine system according to the exemplary embodiments, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated. Incidentally, unless clearly used otherwise, expressions in the singular number include a plural meaning.
FIG. 1 is a conceptual view illustrating a double suction type turbo generator supported by a foil bearing.
As illustrated in FIG. 1, a turbo generator 100 applied to the present disclosure may be implemented into a double suction type. More specifically, the turbo generator 100 may include a first turbine part 110 and a second turbine part 120.
The first turbine part 110 may include a first impeller 111 rotatable by an introduced fluid. The fluid introduced into the first turbine part 110 may be steam of high temperature and high pressure. Thermal energy and kinetic energy stored in the steam may be changed into kinetic energy of the first impeller 111, followed by conversion into electric energy. The steam, which has generated the kinetic energy in the first turbine part 110, may be converted into a state of low temperature and low pressure, thereby being emitted to the outside of the first turbine part 110.
The second turbine part 120 may include a second impeller 121 rotatable by steam. As illustrated, a generator may be interposed between the first impeller 111 and the second impeller 121. For example, the generator may include a single rotating shaft 131, and the first impeller 111 and the second impeller 121 may be coupled to both ends of the single rotating shaft 131, respectively. Here, the first impeller 111 and the second impeller 121 may have the same shape.
More specifically, the single rotating shaft 131 may be supported by a foil bearing 140. The foil bearing 140 is a mechanical element which rotates and supports the single rotating shaft 131 through gas film lubrication, in a non-contacting manner. The foil bearing 140 may be used as an intermediate/low temperature type. In such a manner, the present disclosure may implement a system, which has a simplified structure, can reduce maintenance costs and can minimize a power loss, all by virtue of employing such foil bearing.
The foil bearing 140 may include first and second foil bearings 141 and 142 which are disposed with a predetermined spacing therebetween, and a stator 132 made of a coil and located between the first and second foil bearings 141 and 142. In addition, a magnet (not illustrated) may be disposed in the single rotating shaft 131.
As such, the turbo generator 100 disclosed herein may have the structure that impellers having the same shape are located at both ends of a turbine and journal foil bearings support the both ends. The magnet may be disposed in a center of a shaft structure, so as to interact with a stator made of a coil. As illustrated, in response to an introduction of steam, a turbine wheel may be rotated by pressure of the steam so as to produce electric power.
Also, the second impeller 121 of the second turbine part 120 may be rotated by steam evaporated within a cycle unit 200 (see FIG. 2), in which the fluid circulates along a rankine cycle. The present disclosure proposes a method of improving efficiency of the turbine and optimizing an output of the turbine through the structure. Hereinafter, the structure and the method will be described in more detail with reference to FIGS. 2 and 3.
FIG. 2 is a conceptual view of a hybrid turbo generator system according to the present disclosure, to which the turbo generator of FIG. 1 is applied, and
FIG. 3 is a T-s diagram of an organic rankine cycle using R-245fa.
As illustrated in FIGS. 2 and 3, a turbine generation system according to the present disclosure may include a cycle unit 200 in which a fluid circulates along a rankine cycle. The cycle unit 200, for example, may include a pump 210 (adiabatic compression), a heat exchanger 221, an evaporator 222 (isobaric heating), a second turbine part 120 (adiabatic expansion), and a steam condenser (or condenser) 230 (isobaric condensation).
As illustrated, a fluid, which has been evaporated in the evaporator 222 of the cycle unit 200 may be condensed by the steam condenser 230. The second turbine part 120 may be located between the evaporator 222 and the steam condenser 230. That is, the fluid which has flowed through the evaporator 222 in the cycle unit 200, as illustrated in FIG. 2, may be introduced into a wing of the turbine to be changed in phase. The phase-changed fluid may then be utilized together with a refrigerant which flows through the condenser. The turbine generation system according to the present disclosure may implement a hybrid structure in such a manner of applying a different operating fluid to each of wings disposed at the both ends of the turbine through such flow of the fluid. For example, in order to heat a fluid introduced into the first turbine part 110, a burner (not illustrated) may be connected to an introduction opening of the first turbine part 110. Accordingly, the first turbine part 110 may become a steam part which operates under a condition of dry steam.
Referring to those drawings, the turbine generation system according to the present disclosure may be configured in such a manner that a fluid, which is discharged from the first turbine part 110 after rotating the first impeller 111, may be heat-exchanged with a refrigerant of the evaporator 222, which is disposed in the cycle unit 200. To this end, the rankine cycle may be an organic rankine cycle, which receives thermal energy supplied from the fluid discharged from the first turbine part 110. Therefore, the refrigerant, which circulates along the heat exchanger 221 and the evaporator 222, may be an organic refrigerant, for example, R-245fa.
In more detail, the organic refrigerant which circulates along the heat exchanger 221 and the evaporator 222 may be heat-exchanged in the heat exchanger 221 with the fluid, which is discharged from the first turbine part 110. A fluid force of steam, which is sucked using the steam turbine, may first drive the turbine, and an expanded steam, which is discharged from the turbine, may be reduced in pressure, thereby being changed into a low-temperature heat source. Such low-temperature heat source may be applied to the organic rankine cycle using the organic refrigerant (245fa) which flows through the heat exchanger and the evaporator.
A temperature of steam using waste heat typically has an intermediate temperature over 190° C. Hence, the fluid force of the steam sucked using the steam turbine first drives the turbine. The expanded steam, flowed through the turbine, is lowered in pressure to be a low-temperature heat source approximately in the range of 110 to 140° C. The heat source exhibits so low efficiency to directly use a secondary momentum in view of a performance of the steam turbine, and also causes a damage of the turbine due to an expansion of an outlet port and a condensation of steam. These problems can be overcome by the structure disclosed herein.
The present disclosure may employ a structure of a double suction type steam turbine, to improve structural stability and rotordynamic performance of the turbine system.
Also, the present disclosure may employ an intermediate/low temperature type foil bearing, to minimize a volume of a waste heat generation system and enhance generation efficiency.
In addition, the present disclosure may ensure a small steam turbine technology, which allows unused waste heat, generated from medium and small incineration facilities, to be used as energy, brings about an oil substitution effect using the waste heat, and provides high efficiency and high economic feasibility by virtue of configuring a compact system.
The configuration and method of the aforementioned embodiments may not be applied to the hybrid turbine system in a limiting manner, but those embodiments may be configured by selective combination of all or part of each embodiment so as to implement different variations.

Claims

What is claimed is:

1. A turbine generation system, comprising:

a first turbine part that is configured to have a first impeller rotated by an introduced fluid; and

a second turbine part that is configured to have a second impeller rotated by steam, evaporated within a cycle unit, in which the fluid circulates along a rankine cycle,

wherein the fluid, which is discharged from the first turbine part after rotating the first impeller, is heat-exchanged with a refrigerant of an evaporator disposed in the cycle unit.

2. The system of claim 1, wherein a generator is disposed between the first impeller and the second impeller.

3. The system of claim 2, wherein the generator comprises a single rotating shaft having both ends coupled with the first impeller and the second impeller, respectively.

4. The system of claim 3, wherein the single rotating shaft is supported by a foil bearing.

5. The system of claim 4, wherein the foil bearing comprises first and second foil bearings disposed with a predetermined spacing therebetween, and a stator made of a coil is located between the first and second foil bearings.

6. The system of claim 4, wherein a magnet is disposed within the single rotating shaft.

7. The system of claim 1, further comprising a burner connected to an introduction opening of the first turbine part, to heat the fluid introduced into the first turbine part.

8. The system of claim 1, wherein the first impeller and the second impeller have the same shape.

9. The system of claim 1, wherein the cycle unit comprises a condenser that is configured to condense the fluid evaporated in the evaporator, and the second turbine part is disposed between the evaporator and the condenser.

10. The system of claim 1, wherein the rankine cycle is an organic rankine cycle which receives thermal energy supplied from the fluid discharged from the first turbine part.

11. The system of claim 10, wherein a heat exchanger is disposed to be connected to the evaporator of the organic rankine cycle, and

wherein a refrigerant circulating along the heat exchanger and the evaporator is heat-exchanged in the heat exchanger with the fluid discharged from the first turbine part.

12. A turbine generation system comprising:

wherein the first impeller and the second impeller are mounted to both ends of a single rotating shaft, respectively.

13. The system of claim 12, wherein the fluid, which is discharged from the first turbine part after rotating the first impeller, is heat-exchanged with a refrigerant of an evaporator disposed in the cycle unit.