GAS TURBINE ENGINE SYSTEM THAT USES ORGANIC MEDIUM

A gas turbine engine system is provided which achieves high efficiency while using sunlight as a heat source. In a gas turbine engine system including: a compressor configured to compress a first working medium; a heater configured to heat the compressed first working medium by an external heat source; a turbine configured to output power from the first working medium; and an intermediate cooler provided at the compressor and configured to cool the first working medium compressed by a low-pressure compression part of the compressor and supply the first working medium to a high-pressure compression part of the compressor, an organic Rankine cycle engine using, as a second working medium, an organic substance which is a cooling medium of the intermediate cooler is provided.

CROSS REFERENCE TO THE RELATED APPLICATION

This application is based on and claims Convention priority to Japanese patent application No. 2012-086210, filed Apr. 5, 2012, the entire disclosure of which is herein incorporated by reference as a part of this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a complex gas turbine engine system equipped with an organic Rankine cycle engine which uses organic substance as a working medium.

2. Description of Related Art

In recent years, as a solution to the environment problems or the energy problems, a distributed energy supply system has been proposed in which relatively small power plants are installed near electric power consumers and supply electric power. As one power source which is part of the distributed energy supply system, use of a middle-sized or small-sized gas turbine engine has been suggested (e.g., Patent Document 1). For a distributed power source, it is particularly an important issue to improve the efficiency.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

However, as a method for improving the efficiency of a middle-sized or small-sized gas turbine, increasing of a temperature or increasing of a pressure ratio is difficult due to restrictions in size. In addition, conventionally, a regenerative cycle in which exhaust heat from a gas turbine is used for preheating a working gas is established, or a cogeneration system using exhaust heat from a gas turbine as a heat source for a steam turbine is established, thereby comprehensively improving the efficiency of the entire system. However, it is very difficult to further increase the efficiency by developing an engine with a low pressure ratio suitable for a regenerative cycle or developing a low-output and high-efficient steam turbine for use in a cogeneration system.

Therefore, in order to solve the above-described problems, an object of the present invention is to provide a combined-type gas turbine engine system which achieves high efficiency by very effectively utilizing heat from a gas turbine engine.

In order to achieve the above-described object, a gas turbine engine system according to the present invention includes: a compressor configured to compress a first working medium; a heater configured to heat the compressed first working medium utilizing an external heat source; a turbine configured to output power from the first working medium; an intermediate cooler provided at the compressor and configured to cool the first working medium compressed by a low-pressure compression part of the compressor and supply the first working medium to a high-pressure compression part of the compressor; and an organic Rankine cycle engine using, as a second working medium, an organic substance which serves as a cooling medium of the intermediate cooler.

With this configuration, by using a low-boiling-point organic substance as the working medium of the Rankine cycle engine combined with a gas turbine engine, it is possible to effectively use the heat of the relatively-low-temperature working medium passing through the compressor, and thus it is possible to obtain very high efficiency for the entire engine system.

In one embodiment of the present invention, the gas turbine engine system may further include: a heat exchanger provided on a discharge path for discharging the first working medium discharged from the turbine, the heat exchanger using, as a heating medium, the first working medium discharged from the turbine; and an organic Rankine cycle engine using, as a third working medium, an organic substance which serves as a heat receiving medium of the heat exchanger. With this configuration, the organic media are used, and not only the heat of the working medium passing through the compressor but also the heat of the working medium discharged from the turbine are used to output power, and thus it is possible to obtain further high efficiency for the entire engine system.

In one embodiment of the present invention, as the heater, a solar heater configured to heat the first working medium utilizing sunlight as a heat source may be provided. With this configuration, it is possible to increase the efficiency of the engine system while suppressing a load on the environment by using sunlight which is natural energy.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference to the drawings.FIG. 1is a schematic configuration diagram showing a gas turbine engine system (hereinafter, referred to simply as “engine system”) E according to an embodiment of the present invention. The engine system E includes three engine units, namely, a gas turbine engine unit GU, a first Rankine cycle engine unit RU1, and a second Rankine cycle engine unit RU2, and those engine units GU, RU1, RU2drive respective loads such as generators GE1, GE2, GE3.

The gas turbine engine unit GU includes a compressor1which compresses a first working medium M1, a combustor3which is a heater for heating the first working medium M1compressed by the compressor1, and a first turbine5which outputs power from the combusted first working medium M1. In the present embodiment, an air may be used as the first working medium M1.

The compressor1includes a low-pressure compression part1aand a high-pressure compression part1b, and is provided with an intermediate cooler9arranged between the low-pressure compression part1aand the high-pressure compression part1b.By cooling the first working medium M1, compressed by the low-pressure compression part1a,with the intermediate cooler9, compression work of the high-pressure compression part1bis reduced, and the efficiency is improved. The high-pressure first working medium M1discharged from the compressor1passes through a regenerative heat exchanger13and then is sent to the combustor3. The regenerative heat exchanger13preheats the first working medium M1flowing from the compressor1toward the combustor3by using the heat of the high-temperature first working medium M1discharged from the first turbine5.

A heat exchanger15is further provided on a downstream of the regenerative heat exchanger13on a discharge path11which discharges the first working medium M1discharged from the first turbine5to the outside. The first working medium M1discharged from the regenerative heat exchanger13passes through the heat exchanger15as a heating medium and then is discharged to the outside.

In the first Rankine cycle engine unit RU1, a second turbine17is driven by a second working medium M2which has been heated into a gaseous state utilizing, as a heat source, the heat of the first working medium M1passing through the intermediate cooler9, and power is outputted through the second turbine17. The second working medium M2discharged from the second turbine17is condensed by a first condenser19and then is supplied to the intermediate cooler9and the second turbine17again.

The first Rankine cycle engine unit RU1is configured as an organic Rankine cycle engine using an organic substance as the second working medium M2. In particular, the temperature of the first working medium M1that is being compressed in the compressor1is about 100° C. to 200° C., which is relatively low, thus an organic medium having a low boiling point may be used as the second working medium M2. In this example, a fluorocarbon-based organic medium, for example, HFC-134a, HFC-245fa, HFC-365mfc, or the like, may be used.

In the second Rankine cycle engine unit RU2, a third turbine21is driven by a third working medium M3which has been heated utilizing, as a heat source, the heat of the first working medium M1passing through the heat exchanger15as a heating medium as described above, and power is outputted through the third turbine21. The third working medium M3discharged from the third turbine21is condensed by a second condenser23and then is supplied to the heat exchanger15and the third turbine21again.

The second Rankine cycle engine unit RU2is also configured as an organic Rankine cycle engine using an organic substance as the third working medium M3. The first working medium M1, which is an exhaust gas discharged from the first turbine5, is kept at a relatively high temperature of about 200° C. to 300° C. even after passing through the regenerative heat exchanger13, thus it is possible to use an organic medium having a higher boiling point than that of the second working medium M2. In this example, a petroleum-based organic medium, for example, butane or pentane, may be used.

The second Rankine cycle engine unit RU2may be configured as an ordinary steam turbine using water as the third working medium M3. Alternatively, the second Rankine cycle engine unit RU2may be omitted, but the organic media are used as in the present embodiment, not only the heat of the first working medium M1passing through the compressor1but also the heat of the first working medium M1discharged from the first turbine5are used to output power, and thus it is possible to obtain further high efficiency for the entire engine system E.

In addition, as a modification of the present embodiment, as shown inFIG. 2, a solar heater31which uses sunlight SL as a heat source may be additionally provided at the upstream side of the combustor3as a heater which heats the first working medium M1compressed by the compressor1. By providing such a configuration and heating the first working medium M1again by using the sunlight SL which is natural energy, the efficiency of the engine system E is further improved.

As described above, in the engine system E according to the present embodiment, since the organic substance having a low boiling point is used as the working medium M2of the Rankine cycle engine (in particular, the first Rankine cycle engine RU1) combined with the gas turbine engine unit GU, it is possible to effectively use the heat of the relatively-low-temperature working medium passing through the compressor1, and thus it is possible to obtain very high efficiency for the entire engine system E.

Although the present invention has been described above in connection with the embodiments thereof with reference to the accompanying drawings, numerous additions, changes, or deletions can be made without departing from the gist of the present invention. Accordingly, such additions, changes, or deletions are to be construed as included in the scope of the present invention.

REFERENCE NUMERALS