JP3788379B2 - Reformed fuel-fired gas turbine equipment and oil heating method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reformed fuel-fired gas turbine facility and an oil heating method thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a combined gas turbine facility that is operated with a reformed fuel obtained by reforming and reducing the weight of heavy oil by raising the temperature and pressure of heavy oil and mixing it with supercritical water produced separately.
[0003]
[Problems to be solved by the invention]
In a fuel-fired combined gas turbine facility that reforms heavy oil, it is necessary to raise the temperature of the heavy oil to about 350 ° C. in order to reform the heavy oil. In the conventional system, the temperature of heavy oil is directly increased by an exhaust heat recovery boiler installed downstream of the combined gas turbine. However, since heavy oil contains corrosive components such as sulfur and vanadium, the heavy oil-side heat transfer tube may be corroded / damaged. An exhaust gas of about 550 ° C. containing oxygen flows in the exhaust heat recovery boiler, and if heavy oil leaks from the heat transfer tube, a fire may occur.
[0004]
An object of the present invention is to provide a reformed fuel-fired gas turbine facility and an oil heating method thereof that prevent fire even if heavy oil whose temperature has been raised is increased and leak, and that has improved reliability.
[0005]
[Means for Solving the Problems]
The present invention relates to a reformed fuel-fired gas turbine facility including a gas turbine that is operated with a reformed fuel obtained by heating and pressurizing heavy oil and reforming and lightening the heavy oil that has been heated and pressurized. A heat transfer pipe having a double pipe structure is installed in an exhaust heat recovery boiler through which exhaust gas installed downstream of the gas turbine flows , and the heavy oil is supplied to the inner pipe of the double pipe , A means for preventing fire due to leakage of heavy oil from the inner pipe of the double pipe into the discharge boiler is provided,
The means is characterized in that a non-combustible fluid is supplied to the outer pipe of the double pipe.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
A heat transfer pipe with a double pipe structure is installed in the exhaust heat recovery boiler installed downstream of the gas turbine, the heavy oil is supplied to the inner pipe of the double pipe, and the outer pipe of the double pipe is not burned Therefore, it is possible to improve the reliability.
[0007]
Rather than directly heating heavy oil with an exhaust heat recovery boiler, a heat transfer pipe with a double pipe structure is installed in the exhaust heat recovery boiler installed downstream of the gas turbine, and the inner pipe of the double pipe is installed. Heavy oil can be achieved by supplying a non-combustible fluid to the outer tube and exchanging heat with the exhaust gas flowing in the exhaust heat recovery boiler and the heavy oil via the non-combustible fluid. With such a configuration, even if heavy oil leaks from the inner heat transfer tube, it mixes with the fluid flowing through the outer tube, so that a fire does not occur.
[0008]
As the non-combustible fluid flowing through the outer pipe of the double pipe, water that generates steam for steam turbine in the exhaust heat recovery boiler is preferably used. Water flowing through the outer pipe of the double pipe also exchanges heat with the exhaust gas. By recovering the heat with steam for the steam turbine, it is possible to reduce a decrease in the overall thermal efficiency.
[0009]
Heavy oil contains corrosive components for metals such as sulfur and vanadium. In particular, the corrosive action of the heat exchanger tube of the heat exchanger is considered to be significant under high temperature and high pressure conditions. The countermeasure is to use a material having high corrosion resistance, but at the same time leads to an increase in cost. For this reason, a relatively inexpensive material is used as the base material of the inner heat transfer tube of the double tube, and the cost is increased by thermally spraying or welding a material having excellent corrosion resistance to the inside that directly contacts heavy oil. Therefore, it is possible to improve the reliability of the heat transfer tube and the heat exchanger having excellent corrosion resistance.
[0010]
The pressure of the steam in the heat transfer tube is measured by installing a pressure sensor in the heat transfer tube of the double tube. When the oil leaks from the heat transfer tube, the internal pressure of the outer heat transfer tube increases, so that leakage of heavy oil to the outer heat transfer tube can be confirmed through the pressure. In the event of a leak, the heavy oil supply to the inner pipe is stopped to minimize the entry of oil into the steam.
[0011]
FIG. 3 shows a combined gas turbine operated with a reformed fuel obtained by reforming and reducing the weight of heavy oil by raising the temperature of the heavy oil and mixing it with supercritical water produced separately.
[0012]
In FIG. 3, 1 is a heavy oil tank, 2 is a heavy oil pressure pump, 3 is a heavy oil supply system, 4 is a heat transfer pipe for heavy oil heat exchange, 5 is a water tank, and 6 is a water pressure pump. , 7 is a water supply system, 8 is a heat transfer pipe for water heat exchange, 9 is an exhaust heat recovery boiler, 10 is a gas turbine, 11 is a reformer, 12 is a condenser, 13 is a reformed fuel supply system, and 14 is a pressure reducing valve. , 15 is a combustor, 16 is heavy oil, 17 is water, 18 is exhaust gas, 19 is reformed fuel, 20 is steam for a steam turbine, 21 is a steam turbine, and 22 is a generator.
[0013]
The heavy oil 16 supplied from the heavy oil tank 1 is pressurized to about 25 Mpa by the pressurizing pump 2 and exchanges heat with the exhaust gas at about 550 ° C. in the heat transfer tube 4 installed in the exhaust heat recovery boiler 9. As a result, the temperature is raised to about 350 ° C. Similarly, the water 17 supplied from the water tank 5 is boosted to about 25 Mpa by the pressurizing pump 6, and is heat-exchanged with the exhaust gas at about 550 ° C. in the heat transfer tube 8 installed in the exhaust heat recovery boiler 9. The temperature is raised to about 450 ° C. The reformed fuel 19 is produced by mixing the heavy oil 16 and the supercritical water 17 that have been heated and pressurized, respectively, in the reformer 11. The reformed fuel 19 is decompressed by the decompression valve 14 and supplied to the combustor 15 to drive the gas turbine 10. Further, the steam turbine 21 is driven by the steam 20 generated in the exhaust heat recovery boiler 9.
[0014]
In a fuel-fired combined gas turbine facility that reforms heavy oil, it is necessary to raise the temperature of the heavy oil to about 350 ° C. in order to reform the heavy oil. When the temperature of heavy oil is increased directly in the exhaust heat recovery boiler installed downstream of the combined gas turbine, the heavy oil side heat transfer tube is contained in the heavy oil because it contains corrosive components such as sulfur and vanadium. May corrode / break. Further, exhaust gas at about 550 ° C. containing oxygen flows in the exhaust heat recovery boiler, and if heavy oil leaks from the heat transfer tube, there is a possibility of a fire.
[0015]
Hereinafter, the illustrated embodiment will be described in detail. FIG. 1 shows a first embodiment of the present invention. In FIG. 1, 1 is a heavy oil tank, 2 is a heavy oil pressure pump, 3 is a heavy oil supply system, 5 is a water tank, 6 is a water pressure pump, 7 is a water supply system, and 8 is water heat. Replacement heat transfer tube, 9 is an exhaust heat recovery boiler, 10 is a gas turbine, 11 is a reformer, 12 is a condenser, 13 is a reformed fuel supply system, 14 is a pressure reducing valve, 15 is a combustor, 16 is heavy oil , 17 is water, 18 is exhaust gas, 19 is reformed fuel, 20 is steam for steam turbine, 21 is a steam turbine, 22 is a generator, and 23 is a heat exchanger composed of a double pipe of heavy oil and steam. is there.
[0016]
Further, FIG. 2 shows the structure of the heat exchanger 23. In FIG. 2, 16 is heavy oil, 18 is exhaust gas, 20 is steam for steam turbine, 23 is a heat exchanger composed of a double pipe of heavy oil and steam, 24 is a heat transfer pipe for heavy oil, and 25 is A steam heat transfer tube 26 is a header of the steam heat transfer tube.
[0017]
In the exhaust heat recovery boiler 9 installed downstream of the gas turbine 10, the steam 20 for driving the steam turbine 21 is manufactured by exchanging heat with the exhaust gas 18 via the heat transfer pipe 25. The heavy oil 16 supplied from the tank 1 is pressurized to about 25 MPa by the pressurizing pump 2 and then exchanges heat with the steam around the heat transfer tube 25 through the heat transfer tube 24 installed in the heat transfer tube 25. As a result, the temperature is raised to about 350 ° C. Further, the water 17 supplied from the water tank 5 is pressurized to about 25 Mpa by the pressurizing pump 6, and exchanges heat with the exhaust gas at about 550 ° C. through the heat transfer pipe 8 installed in the exhaust heat recovery boiler 9. The temperature is raised to about 450 ° C. The reformed fuel 19 is produced by mixing the heavy oil 16 and the supercritical water 17 that have been heated and raised, respectively, in the reformer 11.
[0018]
Since supercritical water is chemically highly active, a component having a high molecular weight in heavy oil can be easily decomposed into a component having a low molecular weight. Therefore, it is possible to easily improve the combustion stability that greatly depends on the content of the large molecular weight component and the viscosity of the fuel. At the same time, supercritical water has the property of easily mixing with oil even at the molecular level, so that heavy oil can be reformed in a uniform state. Furthermore, since the reformed fuel recovers a kind of heat in the exhaust heat recovery boiler 9 and returns the heat to the gas turbine side, the thermal efficiency of the entire combined cycle can be improved.
[0019]
The reformed fuel 19 produced in this manner is decompressed by the pressure reducing valve 14 and supplied to the combustor 15 to drive the gas turbine 10. Further, the steam turbine 21 is driven by the steam 20 generated in the exhaust heat recovery boiler 9. The steam 20 is condensed in the condenser 12 and returned to the exhaust heat recovery boiler again.
[0020]
Next, FIG. 4 shows a heat transfer tube structure of a heavy oil / steam double tube heat exchanger as a second embodiment. In FIG. 4, 16 is heavy oil, 20 is steam for steam turbine, 24 is a heat transfer tube for heating heavy oil, 25 is a heat transfer tube for heating steam, and 27 is a material excellent in corrosion resistance. Heavy oil contains components that corrode metals such as sulfur and vanadium. In order to suppress the corrosion, among SUS and the like, it is desirable to apply SUS316, SUS310S, etc., which have particularly strong corrosion resistance, to the heat transfer tube.
[0021]
On the other hand, when steam / water is mixed, stress corrosion cracking occurs in the SUS material. Therefore, it is desirable to use a material that does not cause stress corrosion cracking due to steam, such as carbon steel, as the base material of the heat transfer tube in contact with steam / water. For this reason, carbon steel is used for the heat transfer tube 24, and a material 27 having excellent corrosion resistance such as SUS is used on the inner surface of the heat transfer tube 24 so that heavy oil flowing inside does not enter from the gap of the belt. Fix by welding. By applying such a structure to the heat transfer tube 24, it is possible to suppress the occurrence of stress corrosion cracking due to the external steam 20 and corrosion due to sulfur contained in the internal heavy oil 16.
[0022]
Next, a third embodiment of the present invention is shown in FIG. In FIG. 5, 16 is heavy oil, 20 is steam for steam turbine, 24 is a heat transfer tube, 28 is a pressure sensor, and 29 is a pressure measuring device. The vapor pressure in the heat transfer tube 25 is measured by the pressure sensor 28. The measured pressure is measured by the pressure measuring device 29. The pressure trend does not change if the gas turbine load is constant. The pressure of the steam itself is usually about 4 MPa at the rated conditions.
[0023]
On the other hand, the heavy oil pressurized to the steam pressure used for the steam turbine is 25 Mpa, which is about six times larger than the steam pressure. Therefore, when there is a leak in the heat transfer tube, the pressure in the heat transfer tube increases as shown in FIG. Thereby, the leak of heavy oil is detectable by measuring a pressure. Simultaneously with the leak detection, the heavy oil supply to the heat exchanger is shut off, so that the mixing of the heavy oil into the steam can be minimized.
[0024]
As described above, according to the first embodiment of the present invention, the heavy oil heating heat transfer tube has a double tube structure, and the heavy oil is supplied to the inner tube by supplying heavy oil and the outer tube with steam. Can be heated indirectly through steam. Therefore, even when heavy oil leaks from the inner heat transfer tube, the inside of the outer heat transfer tube is steam, so that no fire occurs.
[0025]
Further, according to the second embodiment of the present invention, in the heat transfer tube of the heavy oil heating heat exchanger, a material resistant to stress corrosion cracking due to steam / water coexistence atmosphere such as carbon steel is used as a base material, A material having excellent corrosion resistance, such as SUS, can be used. With such a structure, it is possible to prevent the occurrence of stress corrosion cracking due to steam flowing outside and corrosion due to the sulfur content of the heavy oil inside.
[0026]
According to the third embodiment of the present invention, a heavy oil heating heat exchanger heat exchanger tube is provided with a pressure sensor for monitoring, and if an abnormal pressure increase is observed, the heavy oil to the heat exchanger is By stopping the supply, it is possible to minimize the leakage of heavy oil from the heat transfer tube and mixing with the steam.
[0027]
【The invention's effect】
According to the present invention, there is an effect that it is possible to provide a reformed fuel-fired gas turbine facility and an oil heating method thereof that can prevent a fire even if heavy oil whose temperature has been increased is leaked and that has improved reliability.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a combined gas turbine facility operated with heavy oil reforming fuel using the present invention.
FIG. 2 is a diagram showing a double-pipe heavy oil heat exchanger structure using the present invention.
FIG. 3 is a diagram showing an embodiment of a combined gas turbine facility operated with heavy oil reformed fuel.
FIG. 4 is a view showing a heat transfer tube structure of a double-tube heavy oil heating heat exchanger of a combined gas turbine operated with heavy oil reformed fuel using the present invention as a second embodiment.
FIG. 5 is a diagram showing a fourth embodiment of a combined gas turbine operated with heavy oil reformed fuel using the present invention.
FIG. 6 shows the pressure change in the heat transfer tube when heavy oil leaks.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Heavy oil tank, 2 ... Heavy oil pressurization pump, 3 ... Heavy oil supply system, 4 ... Heat transfer pipe for heavy oil heat exchange, 5 ... Water tank, 6 ... Water pressurization pump, 7 ... Water Supply system, 8 ... Heat transfer tube for water heat exchange, 9 ... Waste heat recovery boiler, 10 ... Gas turbine, 11 ... Reformer, 12 ... Condenser, 13 ... Reformed fuel supply system, 14 ... Pressure reducing valve, 15 ... Combustion 16 ... heavy oil, 17 ... water, 18 ... exhaust gas, 19 ... reformed fuel, 20 ... steam for steam turbine, 21 ... steam turbine, 22 ... generator, 23 ... heat exchanger, 24, 25 ... Heat transfer tube, 26 ... header, 27 ... material, 28, 33 ... pressure sensor, 29, 34 ... pressure measuring device, 30 ... outlet for low temperature steam or condensed water, 31 ... cavity for high temperature steam, 32 ... low temperature steam or condensed water Cavity.

Claims (6)

The heavy oil was heated boost, the reformed-fuel-burning gas turbine plant equipped with a gas turbine is operated with the heavy oil heated boosted by reforming and lightening the reformed fuel,
A heat transfer pipe having a double-pipe structure is installed in an exhaust heat recovery boiler in which exhaust gas installed downstream of the gas turbine flows , and the heavy oil that has been heated and pressurized is supplied to the inner pipe of the double pipe. configured, a means to prevent fire caused by the heavy oil from leaking to the exhaust heat recovery boiler from inner tube of the double tube,
As the means, a reformed fuel-fired gas turbine equipment is configured to supply a non-combustible fluid to the outer pipe of the double pipe. The heavy oil was heated boost, the reformed-fuel-burning gas turbine plant equipped with a gas turbine is operated with the heavy oil heated boosted by reforming and lightening the reformed fuel,
A heat transfer pipe having a double-pipe structure is installed in an exhaust heat recovery boiler in which exhaust gas installed downstream of the gas turbine flows , and the heavy oil that has been heated and pressurized is supplied to the inner pipe of the double pipe. configured, a means to prevent fire caused by the heavy oil from leaking to the exhaust heat recovery boiler from inner tube of the double tube,
As this means, a non-combustible fluid is supplied to the outer tube of the double tube, and heat exchange is performed between the exhaust gas flowing in the exhaust heat recovery boiler and the heavy oil via the non-combustible fluid. A reformed fuel-fired gas turbine facility.   The reformed fuel-fired gas turbine equipment according to claim 2, wherein water that generates steam for steam turbine in the exhaust heat recovery boiler is used as the non-combustible fluid flowing through the outer pipe of the double pipe. A reformed fuel-fired gas turbine facility.   4. The reformed fuel-fired gas turbine equipment according to claim 2, wherein a metal having excellent corrosion resistance is sprayed on the inner surface of the inner pipe of the double pipe.   In the reformed fuel-fired gas turbine equipment according to any one of claims 2 to 4, when a pressure change in each part of the inner and outer pipes of the double pipe is measured and an abnormality is recognized in the pressure, the double pipe A reformed fuel-fired gas turbine facility characterized in that the heavy oil supply to the pipe is stopped. In an oil heating method for a reformed fuel-fired gas turbine equipment comprising a gas turbine operated with a reformed fuel obtained by heating and pressurizing heavy oil and reforming and lightening the heavy oil that has been heated and pressurized A double pipe structure heat transfer pipe is installed in the exhaust heat recovery boiler through which the exhaust gas installed downstream of the gas turbine flows , and the heavy oil that has been heated and pressurized is supplied to the inner pipe of the double pipe. Means for preventing fire due to leakage of the heavy oil from the inner pipe of the double pipe into the exhaust heat recovery boiler;
In this means, a non-combustible fluid is supplied to the outer tube of the double tube, and the heavy oil and the exhaust gas flowing in the exhaust heat recovery boiler are heat-exchanged via the non-combustible fluid. An oil heating method for a reformed fuel-fired gas turbine facility.

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