JP2000054852A - Gas turbine combined cycle power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To amplify both enthalpy and exergy and reduce the exergy loss in combustion process by connecting a steam reforming system of fuel to a combustor. SOLUTION: A combustor is connected to an air compressor, and a gas turbine is connected to the combustor to connect a methanol steam reforming reactor to the combustor through the gas turbine. A part of the exhaust steam 12 of a high-pressure steam turbine is supplied to the steam reforming reactor together with methanol, and a reaction heat is also supplied by use of the heat of the exhaust gas 6 of the gas turbine. The steam reforming reactor converts all the methanol is converted to hydrogen and carbon dioxide at about 250 deg.C in the steam reforming reactor, and the methanol steam reformed gas is mixed with natural gas in a mixer and then supplied to the combustor to provide a combustion gas of 1450 deg.C or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combined cycle power generation system which has been actively adopted as a technique for achieving high-efficiency power generation while suppressing the emission of carbon dioxide, which is regarded as the main working gas for global warming. In particular, the present invention relates to a high-efficiency power generation / energy-saving technology characterized in that exergy is amplified by fuel reforming or steam reforming of methanol to reduce exergy loss during combustion.

[0002]

2. Description of the Related Art While global environmental issues are becoming increasingly important, global warming due to carbon dioxide has been widely adopted, and controlling carbon dioxide emissions has been renewed as an urgent issue. Technologies for reducing carbon dioxide within and between industries, such as developing renewable energy represented by solar cells and wind power generation, developing energy-saving measures for existing industrial plants, and developing technologies to improve the efficiency of power generation facilities Development is progressing. Among them, natural gas has attracted attention as a clean energy for electric power with a low carbon content, and its use has been studied.At the same time, natural gas has been used as a fuel to improve power generation efficiency by continuous use with gas turbines and steam turbines. Turbine combined cycle power generation system (GTCC)
The total power generation efficiency has reached nearly 50% due to the combined use with a steam turbine.

[0003] However, in Japan, the fuel shift from low hydrogen content fuel such as coal to natural gas with high hydrogen content has been achieved by securing gas transportation means from natural gas fields, that is, natural gas liquefaction facilities and liquefaction. Due to the difficult problem of requiring large-scale infrastructure investment such as construction of natural gas (LNG) transport ships, construction of LNG receiving terminals, and construction of pipelines, it cannot be easily developed. Therefore, further improvement of power generation efficiency is a focus of technology development. Most of them use steam turbine power generation system control (for example, JP-A-6-159091), steam turbine cooling mechanism design (for example, JP-A-9-170407 and JP-A-10-61457), and use of superalloys. Gas turbine blades and nozzle designs (see, for example,
No. 2, JP-A-7-70679), coupling with low-boiling-point medium cycle power generation and inert gas medium cycle power generation (for example, JP-A-7-166815, JP-A-9-1997)
No. 14560), and there is no technology relating to power generation system design that takes into account the quality of fuel. On the other hand, although technology development for stabilizing the operation mode of the power generation equipment and improving efficiency by improving load following capability is also progressing, switching between the combined power generation mode and the steam turbine single power generation mode (for example,
In most cases, control for detecting a deviation between a target load and an actual load (for example, JP-A-5-272361 and JP-A-8-128304) is performed. In addition, the development of technology for introducing natural gas as a new fuel while increasing the flowability by converting natural gas into a liquid fuel and avoiding large-scale infrastructure investment has been activated, and methanol is a typical example.

The technical development for improving the power generation efficiency described above is as follows.
As long as fossil fuels with a large exergy loss are used, there is a limit in improving the power generation efficiency. In other words, the development of gas turbine combined cycle power generation (GTCC) is intended to improve energy efficiency by collecting combustion energy in cascade using clean gas as a raw material. It does not fall into the category of improving the efficiency of collection, and there is naturally a limit to the cost of improving efficiency.
On the other hand, a composite system has been proposed for the purpose of improving the total energy efficiency by coupling with other plants in view of the limit of efficiency improvement of a single power generation facility. For example, a combination with air separation using a high-temperature oxygen-transporting solid electrolyte (for example, USP-5516359), a combination with a fuel cell (for example, JP-A-9-129255), LN
A combination with G vaporization (for example, JP-A-9-14587) and a combination of a cryogenic air separation plant and compressed air storage power generation (for example, JP-A-9-13918) are given. It is an effective technology and is subject to location restrictions.

[0005] In order to improve the power generation efficiency in the gas turbine combined cycle power generation, it is effective to increase the gas temperature at the inlet of the gas turbine and the steam turbine, which has been increasing at an average annual rate of 20 ° C in the past 20 years. Industrialization of a 1450 ° C. class gas turbine is expected to be imminent. The temperature rise of the gas at the gas turbine inlet has been achieved by the cooling technology of combustors and turbine blades, and the development of heat-resistant materials. However, when the temperature is further increased to over 1450 ° C., a large amount of In the high temperature combustion field reacts with oxygen to promote the formation of nitrogen oxides (thermal NO
x), this generation suppression is extremely important on environmental issues.
It is known that the generation of nitrogen oxides becomes more remarkable at 1500 ° C or higher, and the improvement of power generation efficiency by increasing the combustion temperature as a technology for addressing energy problems is a trade-off with the reduction of nitrogen oxides as a response to environmental problems. Off relationship.
The premixed combustion technology, ceramic combustor, and catalytic combustion technology, which are known as existing nitrogen oxide suppression technologies, are mainly aimed at suppressing the high-temperature region generated locally in the combustor. Is expected to function effectively up to about 1500 ° C., but beyond that, the applicability remains questionable. Therefore, it is necessary to develop efficiency improvement technology from another point of view in parallel with the technology development aimed at increasing the temperature at the inlet of the gas turbine, and one of them is a power generation system design that takes fuel quality into consideration.

[0006] Methanol has been established as an industrial production technology system using natural gas as a raw material, but its use is mostly used as a chemical agent. In recent years, methanol has been used as a raw material for on-site hydrogen production for semiconductor production plants. Despite progress,
Because it is small, it must be said that its supply capacity is insufficient to use it as fuel for power generation. However, with the increasing use of natural gas as clean energy, attention is being paid to developing liquid fuel technology as a promising means to promote the development of discovered and undeveloped natural gas fields on a global scale. One of the leading candidates. On the other hand, in the field of new uses of methanol, liquid fuels from synthesis gas have been attracting attention in the transportation field, especially in response to demands for improving the energy efficiency of automobiles and stricter exhaust gas regulations.
(Tropush) Replacement of diesel fuel with synthetic oil and development of methanol fuel cell vehicles are being strongly promoted. In addition, development of technology to use methanol as a fuel for power generation,
Demonstration testing has already been performed. There are direct combustion, reforming combustion, and use of fuel cells as technologies for using methanol as a fuel for power generation, but practical use is not expected in large-scale fuel cell development, and there are almost no technical issues with direct combustion. However, the power generation efficiency is almost the same as that of the combined cycle power generation of the natural gas fuel gas turbine. Thermodynamically, the energy loss from natural gas to methanol synthesis is greater than the energy loss in the natural gas LNG conversion process,
It is necessary to develop technology to exceed the natural gas fuel gas turbine combined cycle power generation with energy efficiency in the total process from raw material gas to power generation.

The steam reforming reaction of methanol is represented by the following equation. CH ₃ OH + H ₂ O = 3H ₂ + CO _{2 In the} same reaction, as apparent from the lower heating value shown below,
It is possible to amplify the calorific value (about 14%), which has the potential of improving the power generation efficiency corresponding to the increase.・ Methanol: 152.3 kcal / mol ・ Hydrogen: 57.8 kcal / mol (× 3 = 173.4)
kcal / mol ・ methanol)

Since this reforming reaction proceeds at a low temperature of about 250 ° C., it is possible to use the heat energy of the exhaust gas from the gas turbine. Demonstration tests have been conducted. However, these technical developments are based on the current gas turbine, and assume that the gas temperature at the gas turbine inlet is 1400 ° C. or less. In order to raise the gas temperature at the gas turbine inlet to 1450 ° C. or higher, when a gas containing hydrogen as a main component, such as methanol reformed gas, is used as a fuel, the combustion rate of hydrogen is high, and therefore, the gas is locally localized in the combustion process. Therefore, a high-temperature region is generated and nitrogen oxides are easily generated, so that this suppression technique is inevitable. At present, the premixed combustion technology, the ceramic combustor, and the catalytic combustion technology, which are currently in the research and development stage, cannot be applied to reformed gas containing hydrogen gas as a main component.

Research on hydrogen turbine power generation, which is being pursued as a national project, aims to develop technology assuming a gas turbine inlet gas temperature of about 1700 ° C. Because of the basic concept of using raw oxygen as a combustion agent, the problem of nitrogen oxides is out of consideration. However, until large-scale renewable energy can be used, power consumption is high and it is not efficient.

[0010]

According to the present invention, the improvement of the power generation efficiency of the power generation equipment is reviewed from the viewpoint of the quality of the fuel, and the hydrogen contained in both of them is extracted as hydrogen gas by reacting the fuel or methanol with water vapor, and the hydrogen is removed. Build a high-efficiency gas turbine combined cycle power generation system that amplifies exergy by switching to the main fuel composition and reduces exergy loss that occurs in the irreversible process of combustion compared to direct combustion of fuel and methanol. The purpose is to:

In addition, with a view to improving efficiency by increasing the gas temperature at the inlet of the gas turbine, the combustion speed and the adiabatic flame temperature of the methanol steam reformed gas are reduced in order to suppress the generation of nitrogen oxides, which is a problem at that time. By mixing a fuel containing a hydrocarbon gas lower than hydrogen and supplying it as a fuel, a system having low environmental load characteristics is also constructed.

[0012]

Means for Solving the Problems Gases and methane-containing gases such as natural gas and methanol are not only clean energy sources but also excellent hydrogen sources having a high hydrogen content, and are easily formed by a reforming reaction with steam. We noticed that hydrogen can be amplified. The feature of hydrogen combustion is that the number of moles decreases in the combustion process, and the reaction proceeds in a state where there is no extreme bias toward the reaction generation system due to the decrease in entropy. With this unique combustion mode, exergy loss can be reduced as compared with fossil fuels such as natural gas, as described below. -Exergy loss associated with fossil fuel combustion: 22% or more-Exergy loss associated with hydrogen combustion: 13%

[0013] The process for producing hydrogen from natural gas represented by steam reforming of natural gas and the steam reforming reaction of methanol are based on an endothermic chemical reaction that proceeds at a lower temperature than the combustion reaction. Converting to hydrogen and burning it is considered a kind of heat pump that pumps heat at low temperature (endothermic reaction during reforming) and releases heat at high temperature (exothermic reaction during burning). Hydroconversion power generation is energetically advantageous. Although the efficiency can be improved by using hydrogen as a fuel as described above, the low-cost procurement method is important.

There are various methods for producing hydrogen from a methane-containing gas such as natural gas as a raw material, including steam reforming, partial oxidation, and ATR (Auto Thermal Reforming).
However, these techniques are techniques for obtaining synthesis gas, and focus on the production of chemicals using synthesis gas as a raw material. When pure oxygen cannot be obtained at low cost, the steam reforming method is the most efficient hydrogen production method among these techniques. Further, since the steam reforming reaction is an endothermic reaction, high-temperature operation is desirable from the viewpoint of improving the reaction conversion rate, but it is not desirable in terms of energy efficiency because a large amount of heat energy is required. On the other hand, since steam reforming of methanol proceeds at a low temperature of about 250 ° C., not only can the steam discharged from the steam turbine be used not only as a raw material for reforming reaction but also as a heat source, and the calorific value of the reaction can be increased. Most of the increase contributes to the improvement of power generation efficiency. Furthermore, since the present invention is intended to be incorporated in a gas turbine combined cycle system, it is necessary to operate in a temperature range where gas turbine exhaust heat can be used, and low-temperature operation is desirable.

In order to efficiently advance the steam reforming of methane or methanol by utilizing the exhaust heat of a gas turbine, it is necessary to shift the reaction to a production system. In the present invention, however, excess steam is supplied. The system that shifts the steam reforming reaction to the production system, uses this as a heat medium, and builds a system that recovers it as electric power by combining it with a heat recovery system and a steam turbine. In addition, as a method of shifting the reaction to the production system, there is extraction of the reaction product out of the system, and in the steam reforming reaction system of methane and methanol shown below, hydrogen or carbon dioxide is extracted out of the system. This can accelerate the reaction. CH ₄ + 2H ₂ O = CO ₂ + 4H ₂ CH ₃ OH + H ₂ O = 3H ₂ + CO ₂

As these techniques, there is a hydrogen separation technique using a ceramic membrane, and SiO ₂ , S
A composite material in which iC is coated on porous alumina, or a mixed conductive solid electrolyte having both hydrogen ion and electron permeability in a medium to high temperature range (300 to 900 ° C.), such as B
aCe _0.95 Y _0.05 O ₃ is known. It is also possible to promote the reaction by combining the supply of excess steam with these membrane separation techniques. In addition, hydrogen has a high combustion rate, promotes non-uniformity in the combustion field, and tends to increase the generation of nitrogen oxides by locally forming a high temperature region. We focused on the fact that mixed combustion with relatively slow hydrocarbon gas is effective.

The power generation efficiency can be improved by using a gas containing hydrogen generated by the steam reforming reaction of methanol as a main component as a fuel. On the other hand, hydrogen is a main component of natural gas which is a general-purpose fuel. Compared to methane,
When the combustion speed is high, the adiabatic flame temperature is high, and a high-temperature gas turbine operation (1450 ° C. or higher at the gas turbine inlet gas temperature) is performed using air as a combustion aid, the problem of nitrogen oxide generation is inevitable. Nitrogen oxide emission regulations are in the direction of tightening, and "high efficiency power generation" and "low environmental impact"
As a means for achieving the target having a trade-off relationship in a well-balanced manner, it is effective to mix and supply a fuel containing a hydrocarbon gas having a low combustion rate and a low adiabatic flame temperature to methanol reformed gas. This allows
It is possible to reduce the non-uniformity of the combustion field inside the combustor and suppress the generation of nitrogen oxides.

The means of transporting natural gas is pipeline or LNG, and in any case, the capital investment related to the introduction of natural gas is very large. On the other hand, when transporting natural gas as liquid fuel, special tankers are not required for transport, and receiving equipment such as cryogenic storage tanks, special piping, and vaporizers as in LNG. No infrastructure equipment is required. A typical example of a liquid fuel derived from natural gas is methanol, which is considered to be a fuel that is easier to transport and receive than natural gas. Natural gas, which has the best properties as a methanol feedstock, mainly exists in natural gas fields, and its development is carried out by pipeline or transport to the market by LNG,
Similarly, the need for large-scale investment makes it difficult to develop remote or small and medium-sized gas fields. In Japan, where natural gas resources are scarce except in certain areas, we have to rely on foreign countries for major natural gas sources.
Barriers to the development of small and medium gas fields are even higher.

However, recently, as a means of developing these small and medium-sized gas fields, a GTL for producing a liquid fuel such as methanol has been developed.
(Gas to Liquids) technology development is actively progressing on a global scale, and this is coupled with the trend of distributed energy utilization, enhanced energy saving of automobiles, which are exhaust gas emission sources, and stricter emission regulations. The possibility of realization is thought to be high due to the progress of. In other words, methanol is currently mostly used as a chemical agent and has a small supply scale. However, due to the strong utilization of unused resources (discovered and undeveloped natural gas fields) and the development of low environmental impact and highly efficient energy technologies, It is thought that there is a great possibility that methanol and other clean liquid fuel production technologies will advance under international cooperation and secure a sufficient supply for fuel use.

On the other hand, from a different point of view, methanol as a power generation fuel is considered to be a basic chemical raw fuel that complements the natural gas currently introduced in the consuming area. It should be noted that there is another aspect. In addition, as energy efficiency increases across industries and borders, it is easily anticipated that material recycling of waste, including plastic waste, will progress as part of the establishment of a recycling-oriented economic system. However, these wastes are used as raw materials for integrated production from synthesis gas to methanol, and cleanup of heating and power generation fuel sources by reviewing the energy receiving structure in energy-intensive processes that use large quantities of coal, such as steelmaking plants. Considering the development of methanol and the production of methanol as an effective utilization technology of coal-derived by-product gas, there is a good possibility of supplying and using methanol in a wide area in Japan. Conceivable.

In the present invention, in view of these technical perspectives, both enthalpy and exergy are amplified by converting the fuel gas containing methane or methanol into a fuel gas containing hydrogen as a main constituent by steam reforming. In order to construct a high-efficiency power generation system with reduced exergy loss during the combustion process, steam reforming of fuel gas and methanol is performed using heat energy of gas turbine exhaust gas and steam turbine exhaust steam. At the same time, in response to the technology trend of increasing the gas temperature at the gas turbine inlet, the fuel containing hydrocarbon gas is mixed with methanol steam reformed gas and combusted to suppress nitrogen oxides, which is a problem to be overcome. A gas turbine combined cycle power generation system characterized by this is proposed. The system of the present invention can improve the power generation efficiency as compared with the conventional combined cycle power generation of the fossil fuel direct combustion system, leads to the saving of fossil fuel, and greatly contributes to the reduction of carbon dioxide emission. In addition, the present invention can improve the power generation efficiency as compared with the combined cycle power generation of the direct methanol combustion system, and is directly connected to the expansion of the use of methanol.
By converting natural gas, which requires a great deal of infrastructure investment in transportation and distribution, to methanol, which is a room temperature liquid, the transportation and distribution infrastructure can be significantly reduced, greatly contributing to the development of undeveloped natural gas fields.

The gist of the present invention is as follows. (1) In a gas turbine combined cycle power generation system including a gas turbine coupled to a combustor coupled to an air compressor and a steam turbine cycle coupled to a heat exchanger coupled to the gas turbine, A gas turbine combined cycle power generation system, wherein a steam reforming system according to any one of claims 1 to 3 is combined with a combustor. (2) The gas turbine combined cycle power generation system according to (1), wherein the fuel is a reformed gas mainly composed of hydrogen gas in the fuel steam reforming system. (3) The gas turbine combined cycle power generation system according to (1) or (2), wherein part or all of the exhaust gas of the gas turbine is supplied as a heat source to the fuel steam reforming system. (4) A part of the exhaust gas of the gas turbine and the heat retained by the fuel steam reforming system are supplied to the heat exchanger.
The gas turbine combined cycle power generation system according to any one of (3). (5) In a gas turbine combined cycle power generation system having a gas turbine coupled to a combustor coupled to an air compressor, and a steam turbine cycle coupled to a heat exchanger coupled to the gas turbine, methanol A combined cycle power generation system for a gas turbine, wherein a steam reforming system and a fuel gas supply system are connected to a combustor. (6) The gas turbine combined cycle power generation system according to (5), wherein the gas temperature at the gas turbine inlet is 1450 ° C. or higher. (7) The methanol steam reforming system obtains a methanol-reformed gas by a steam reforming reaction from methanol and exhaust steam of a steam turbine cycle, and converts heat energy required for the steam reforming reaction into exhaust steam of the steam turbine and / or The gas turbine combined cycle power generation system according to (5) or (6), wherein the system is supplied by part or all of the exhaust gas of the gas turbine. (8) The gas turbine combined cycle power generation system according to any one of (5) to (7), wherein the methanol reformed gas and the fuel gas are mixed in advance and then supplied to the combustor. (9) The gas turbine combined cycle power generation system according to any one of (1) to (8), wherein the fuel is natural gas containing methane, coal pyrolysis gas, and / or coke oven gas.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. FIG. 1 is an example of a gas turbine combined cycle power generation system using natural gas as a fuel. This system incorporates a reaction system for steam reforming natural gas using the heat energy of the exhaust gas from a gas turbine, and a thermal energy recovery system for reformed gas. The reformed gas which is converted into hydrogen depending on the quality and has an increased hydrogen concentration is supplied to the combustor. The steam reforming reaction of methane is an endothermic reaction, and it is necessary to use the exhaust heat of a gas turbine as a heat source. However, as shown in the steam reforming reaction formula of methane, 4 moles of hydrogen are converted from 1 mole of methane. As can be seen from the lower calorific value of methane and hydrogen shown below, the calorific value can be increased and exergy can be amplified.・ Lower calorific value of methane: 191.8 kcal / mol ・ Lower calorific value of hydrogen: 57.8 kcal / mol

Excess steam is introduced together with the natural gas so that the steam reforming reaction of the methane in the natural gas proceeds using the exhaust heat of the gas turbine (stream 2). This mixed gas of natural gas and steam is introduced into an adiabatic steam reformer at a temperature of about 600 ° C., and a part of methane is converted into hydrogen and carbon dioxide (stream 3). Here, excess steam is accompanied to shift the reaction to the production system. However, the reaction can be promoted by incorporating a ceramic hydrogen separation membrane into the reaction system and extracting hydrogen out of the system. The reformed natural gas is introduced into a heat exchanger,
The heat of the steam is recovered as steam and used as a drive source of a steam turbine (stream 11). On the other hand, the heat-recovered reformed natural gas (stream 4) is introduced into a gas-liquid separator to remove water, and then pressurized by a compressor (stream 5) and mixed with pressurized air for combustion. It is introduced into the vessel and burned. The combustion exhaust gas (stream 7) is introduced into a gas turbine, and thermal energy is recovered as electric power.

FIG. 2 shows an example of a gas turbine combined cycle power generation system utilizing natural gas containing methane as methanol and hydrocarbon gas fuel. This system incorporates a reaction system for steam reforming methanol using the thermal energy of gas turbine exhaust gas. Almost all of the methanol is converted to hydrogen and carbon dioxide by steam reforming, and the hydrogen concentration is reduced. Is supplied to the combustor together with methane, which is a main component of natural gas. The steam reforming reaction of methanol is an endothermic reaction, and it is necessary to use the exhaust heat of the gas turbine as a heat source.
Since 3 moles of hydrogen are generated from moles of methanol, it is possible to increase the calorific value and amplify exergy.

In order to carry out the steam reforming reaction of methanol efficiently, a part of the steam discharged from the high-pressure steam turbine (stream 12) is supplied together with methanol, and the heat of the gas turbine exhaust gas (stream 6) is utilized. Supply reaction heat. The steam reforming reaction proceeds at about 250 ° C., and substantially all of the methanol is converted to hydrogen and carbon dioxide (stream 2). Here, excess steam is supplied to shift the reaction to the production system.However, the reaction is promoted by incorporating a ceramic porous membrane having a molecular sieve effect into the reaction system and taking out the generated hydrogen out of the system. Is also possible. In order to suppress the formation of nitrogen oxides due to the formation of a local high-temperature region in the combustor, after mixing the steam reformed methanol gas and the natural gas, the mixture is supplied to the combustor, and 1450 ° C
The above combustion gas is obtained (stream 5). This high-temperature combustion exhaust gas is converted into electric energy by a gas turbine generator. After supplying the thermal energy to the methanol steam reformer, the gas turbine exhaust gas exchanges heat with water generated from the steam turbine cycle to complete waste heat recovery (trimes 7, 8). The high-pressure steam (stream 10) generated in the gas turbine exhaust heat recovery step is converted into electric energy by the high-pressure steam turbine. A part of the low-pressure exhaust steam from the high-pressure steam turbine (stream 11) is introduced into the methanol steam reforming reactor and used for the reaction, and the remaining low-pressure exhaust steam is converted into electric energy by the low-pressure steam turbine (stream 11). 13, 14).

The gas used as a fuel in the present invention is not limited to natural gas, but can be applied to all gases including methane, such as coal pyrolysis gas or coke oven gas (COG). And these can be used alone or in combination as appropriate.

[0028]

The present invention will be described below with reference to examples. (Example 1) Table 1 shows the process parameters when the system shown in FIG. 1 was constructed based on the above basic data. still,
The gas component concentration shown in the table is volume%, and the flow rate is 1 million Nm ³
/ Day unit (MNm ³ / D). Table 2 shows the energy balance of the system.

[0029]

[Table 1]

[0030]

[Table 2]

In this embodiment, the mechanical efficiency of the compressor and the expansion turbine is set to 100%, and the adiabatic efficiency is set to 80%.
The following reactions are also considered as side reactions of the methane steam reforming reaction. 2CH ₄ + O ₂ = CO + 4H ₂ Therefore, the reformed natural gas also contains carbon monoxide (stream 5). In the combustor, a thermodynamic equilibrium state is established, and the turbine inlet temperature of the combustion gas is 135.
The amount of air introduced into the combustor is adjusted so as to reach 0 ° C.

(Embodiment 2) Table 3 shows process data when the system shown in FIG. 2 is constructed based on the basic system concept. The gas component concentration shown in the table is% by volume, and the flow rate is shown in kgmol / h. Table 4 shows the energy balance of the system.

[0033]

[Table 3]

[0034]

[Table 4]

In this embodiment, the polytropic efficiency of the compressor, the heat insulating efficiency of the gas turbine are 92.5%, the heat insulating efficiency of the steam turbine is 96%, and the heat insulating efficiency of the pump is 75.
%. In addition, the following side reactions in the steam reforming reaction of methanol are ignored because the amount of generated CO is very small. CO ₂ + H ₂ = CO + H ₂ O In the methanol steam reforming reactor, a thermodynamic equilibrium state is assumed, and the amount of air introduced into the combustor is adjusted so that the turbine inlet temperature of the combustion gas becomes 1450 ° C. I am adjusting.

[0036]

The power generation scale of the system according to the first embodiment of the present invention is about 490,000 kW, and the power generation efficiency is about 59% on the basis of the higher heating value. When the same flow rate of natural gas is directly injected into the combustor to perform gas turbine combined cycle power generation, the power generation efficiency is 53.5%. Therefore, the power generation efficiency of the present invention is improved by about 5.5%. You. That is, the fuel consumption can be reduced by about 10%, and the carbon dioxide emission can be reduced by 10%.

The power generation efficiency of the system according to the second embodiment of the present invention is about 53%. Under the same gas turbine combined cycle power generation operation using natural gas or methanol as the sole fuel, the power generation efficiency is about 53%. Since it is about 52%, the system of the present invention achieves power generation efficiency improvement of over 1%. That is, the fuel consumption can be reduced by more than 2%, and the carbon dioxide emission can be reduced by more than 2%. Further, in the direct combustion power generation of methanol, emission of harmful substances such as acetaldehyde due to incomplete combustion is concerned. However, the system of the present invention can avoid the harmful substances and can reduce the environmental load. Further, in the system of the present invention, natural gas is converted to methanol and used as a fuel with improved transport, storage and distribution properties, so that it is possible to greatly reduce infrastructure maintenance costs required for fuel introduction.

[Brief description of the drawings]

FIG. 1 shows a simplified flow chart of a gas turbine combined cycle power generation system incorporating a natural gas steam reforming reactor and a reformed natural gas heat recovery system in a gas turbine exhaust system, and using the reformed natural gas as a fuel gas. FIG. It should be noted that the circled numbers on the arrows indicating the flows correspond to the stream numbers and are referred to in the text (however, the circle is omitted in the text) and Table 1.

[FIG. 2] A steam reforming reactor for methanol is incorporated in a gas turbine exhaust system, and steam discharged from a high-pressure steam turbine is partially provided as a raw material for a reforming reaction. It is a figure showing a simple flow of a gas turbine combined cycle power generation system which mixes gas and uses it as fuel. It should be noted that the circled numbers on the arrows indicating the flows correspond to the stream numbers, which are referred to in the text (however, circles are omitted in the text) and Table 3.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Kubo 3-35-1, Ida, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Nippon Steel Corporation Technology Development Division (72) Inventor Yoshihiro Kaneda Nakahara-ku, Kawasaki-shi, Kanagawa 3-35-1, Ida Nippon Steel Corporation Technology Development Division (72) Inventor Kenichiro Fujimoto 3-35-1, Ida, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Nippon Steel Corporation Technology Development Division (72) Inventor Hideki Kurimura 1-31-10 Hatagaya, Shibuya-ku, Tokyo Inside Teikoku Oil Co., Ltd. (72) Inventor Shoichi Kaganoi 1-31-10 Hatagaya, Shibuya-ku, Tokyo Teikoku Oil Corporation

Claims (9)

[Claims] A gas turbine combined cycle power generation system comprising a gas turbine coupled to a combustor coupled to an air compressor and a steam turbine cycle coupled to a heat exchanger coupled to the gas turbine. A combined cycle power generation system for a gas turbine, wherein a fuel steam reforming system is connected to a combustor. 2. The gas turbine combined cycle power generation system according to claim 1, wherein the fuel is a reformed gas mainly composed of hydrogen gas in the fuel steam reforming system. 3. The gas turbine combined cycle power generation system according to claim 1, wherein a part or all of the exhaust gas of the gas turbine is supplied as a heat source to the fuel steam reforming system. 4. The gas turbine combined cycle power generation system according to claim 1, wherein a part of the exhaust gas of the gas turbine and the heat retained by the fuel steam reforming system are supplied to the heat exchanger. 5. A combined cycle power generation system for a gas turbine having a gas turbine coupled to a combustor coupled to an air compressor and a steam turbine cycle coupled to a heat exchanger coupled to the gas turbine. A combined gas turbine combined cycle power generation system wherein a methanol steam reforming system and a fuel gas supply system are connected to a combustor. 6. A gas turbine inlet gas temperature of 1450 ° C.
The gas turbine combined cycle power generation system according to claim 5, which is as described above. 7. A methanol steam reforming system obtains a methanol-reformed gas by a steam reforming reaction from methanol and exhaust steam of a steam turbine cycle, and transfers heat energy required for the steam reforming reaction to exhaust steam of the steam turbine and steam. The gas turbine combined cycle power generation system according to claim 5 or 6, wherein the system is supplied by part or all of the exhaust gas of the gas turbine. 8. The method according to claim 5, wherein the methanol reformed gas and the fuel gas are mixed in advance and then supplied to the combustor.
The gas turbine combined cycle power generation system according to the above paragraph. 9. The fuel according to claim 1, wherein the fuel is natural gas containing methane, coal pyrolysis gas and / or coke oven gas.
The gas turbine combined cycle power generation system according to any one of claims 8 to 8.