JPS61192816A - Compound type power generation system - Google Patents

Abstract

PURPOSE:To efficiently utilize fuel and improve the power generation efficiency by reacting a portion or all the fuel supplied into a gas turbine by utilizing the waste heat of the gas turbine and converting the fuel into the secondary fuel having the high combustion energy. CONSTITUTION:In the captioned system, power generation output (e) is obtained by combusting the fuel (a) together with the combustion air (b) in a combustor 1 and driving a gas turbine power generation system 2 by the combustion energy. The exhaust gas (c) supplied from the power generation system 2 is introduced into a waste-heat boiler system 3, and a steam turbine system 4 is driven by the generated steam (g), and the steam (g) which completes work is returned into a condenser 5. In this case, the fuel (a) supplied into the combustor 1 is allowed to pass through a reactor 7 for chemical treatment of fuel installed into the flue of the exhaust boiler system 3 and coverted to the secondary fuel (a') having the high combustion energy. Further, a Rankine turbine power generation system 8 is added into the steam turbine power generation system 4, and the heat loss discharged from the condenser 5 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combined power generation system with improved power generation efficiency.

[Conventional technology]

Recently, a combined power generation system that combines a gas turbine and a steam turbine driven by its exhaust heat energy has been attracting attention as a new technology that can effectively utilize clean fuels such as LNG vaporized gas. FIG. 5 is a block diagram showing a schematic configuration of this type of system, and FIG. 6 is a diagram showing an example of the configuration. In the figure, reference numeral 1 indicates a combustor, and this combustor 1 combusts the supplied fuel a together with combustion air, and uses the combustion energy to drive the gas turbine power generation system.

As shown in FIG. 6, this gas turbine power generation system l includes a gas turbine 2a, a generator 2b driven by the turbine output, and an air compressor 2c for the combustion air, and generates a power generation output e. It has gained. The exhaust gas C from the gas turbine power generation system 1 is discharged through the flue 3& of the exhaust heat gauge system 1. Inside this flue 3a, there is a water supply preheater 3b for Dira steam and a steam generator 3c.
is provided, and the thermal energy of the exhaust heat gas C is recovered to generate steam g. This steam g is supplied to a steam turbine 4a of a steam turbine power generation system f, and a generator 4b connected to the steam turbine 4a is driven to obtain a turbine output f. The steam g that has done work in the steam turbine 41L is supplied to the condenser 5,
After being cooled by the cooling water d flowing through the condenser 5,
The cooling water is supplied to the feed water preheater 3b via the cooling water pump 6. Thereafter, the steam g is circulated by recovering the thermal energy of the exhaust heat gas C as described above.

FIG. 7 is a diagram schematically showing the energy relationship in the system configured as described above, in which the symbol F indicates the energy possessed by the fuel a, L1 is the loss energy in the gas turbine 2a, and L2 is the steam turbine Loss energy, W, at 4a.

W2 indicates the generated energy obtained via the generators 2b and 4b.

In this way, according to this system, a part of the energy that could not be extracted by the gas turbine power generation system can be extracted by the steam turbine power generation system, which not only improves the power generation efficiency but also improves the efficiency of the fuel a. can be used effectively.

[Problem that the invention seeks to solve]

According to the above configuration, the thermal energy recovery of the exhaust heat gas C is
It depends only on the steam turbine power generation system f, therefore,
There is a problem in that a considerable amount of thermal energy is released from the condenser 5 as hot waste water. Furthermore, there has been a tendency for the operating temperatures of the gas turbine power generation systems to rise, and as a result, there has been a problem in that the degree of dependence on the steam turbine power generation system 1 and the amount of hot water discharge have further increased.

The present invention has been made based on the above points, and its purpose is to reduce the dependence on the steam turbine power generation system, reduce the amount of heated wastewater discharged, and, in turn, improve the effective use of fuel. An object of the present invention is to provide a combined power generation system capable of improving power generation efficiency.

[Means for solving problems]

That is, the combined power generation system according to the present invention includes a gas turbine and a multiple Rankine turbine system that is driven by exhaust heat energy from the gas turbine and uses two or more types of working fluids. A part or all of the reactant added to the fuel is chemically reacted using a part of the exhaust heat energy of the gas turbine, and converted into a secondary fuel with high combustion energy to be used in the gas turbine. The present invention is characterized in that a part of the exhaust heat energy from the gas turbine is recovered multiple times by the multiple Rankino turbine system.

[Effect]

In other words, part or all of the fuel supplied to the gas turbine, or the fuel to which reactants have been added, is chemically reacted using part of the exhaust heat energy of the gas turbine, resulting in a secondary fuel with higher combustion energy. By converting the waste heat energy into fuel and supplying it to the gas turbine, a part of the waste heat energy of the gas turbine is recycled as an increase in the combustion energy of the fuel, and a part of the waste heat energy from the gas turbine is also recycled by the multiple Rankine turbine system. It is intended to be collected in multiple ways.

〔Effect of the invention〕

Therefore, it becomes possible to effectively utilize the exhaust heat from the gas turbine, thereby reducing the dependence on the steam turbine system and reducing the amount of heated wastewater discharged, which in turn makes it possible to improve power generation efficiency. The effect is great.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4. Note that parts that are the same as those in the prior art are denoted by the same reference numerals, and their explanations will be omitted.

FIG. 1 is a block diagram showing a schematic configuration of a system according to this embodiment, and FIG. 2 is a diagram showing an example of the configuration. In other words, the combined power generation system according to this embodiment uses a fuel that is supplied to each other between gas turbine power generation systems, or a fuel in which a second reactant is added (hereinafter collectively referred to as "fuel").
is introduced into the chemical fuel treatment reactor 101b through the fuel preheater 101a installed in the flue 3a, and is chemically reacted there using the thermal energy of the hot gas C of the gas turbine 2a. The fuel a is processed and converted into a secondary fuel a' having higher combustion energy, which is supplied to the gas turbine 2a via the combustor 1.

In addition, as shown in Figure 2, the steam turbine power generation system has a separate Rankine turbine power generation system 1 that operates in a lower temperature range.
02 is added. This Rankine turbine power generation system 1
By adding 02, it is attempted to reduce the heat loss discharged from the condenser 5 as 1-temperature waste water. The Rankine turbine power generation system 102 includes a Rankine turbine 102a and piping. The steam turbine power generation system 102 uses steam (H2O) as a working medium, whereas the Rankine turbine power generation system 102 uses an organic medium or the like as a working medium. Further, the reference numeral 104C in the figure is a heat exchanger, and the reference numeral 104d is a steam (working fluid) pump.

According to the above configuration, as shown in FIG. 3, it is possible to effectively utilize the exhaust heat energy R to increase the energy W obtained from the gas turbine 2a, and as a result, it is possible to improve the power generation efficiency. That is, taking as an example the case where methanol (CH30H) is used as fuel a, the methanol will, in the presence of an appropriate catalyst,
It is decomposed under relatively mild reaction conditions, for example at 250°C to 500°C under a pressure of 30 atmospheres or less, as follows.

CH30f(→CO+ 2H2) This reaction is an endothermic reaction, and the reaction temperature range is the gas turbine combustion exhaust gas c (its temperature is approximately 508°C).
) can be fully utilized. The amount of heat produced by combustion at that time is, for example, as shown in Figure 4, El for liquid methanol, E2 for gaseous methanol, and E3 for a mixed gas of CO and 2H2. There is a relationship E, <E2<E3. Further, the calorific value difference ΔH2 is expressed as ΔH1=E2-E1)0 ΔH2:E3-E2)0, and corresponds to the methanol vaporization heat and methanol decomposition heat, respectively. Therefore, the above chemical reaction is carried out on methanol using the exhaust heat energy of the gas turbine 2a to produce a mixed gas consisting of (CO+2H,2), which is used as the secondary fuel a' to generate gas turbine electricity through the combustor 1. By supplying them to each other, the apparent calorific value of methanol can be increased by (ΔH1+ΔH2). As a result, a part of the exhaust heat energy from the gas turbine 2a is converted into chemical energy,
The steam turbine power generation system is recirculated to the gas turbine 2 &! And the exhaust heat energy flowing into the Rankine turbine power generation system 102 is reduced.

The above-mentioned methanol chemical reaction process requires a suitable catalyst, and any conventionally known catalyst may be used as appropriate. It is preferable to use the ones introduced in the above publications.

As described above, according to this system using methanol as fuel a, the methanol obtains the thermal energy necessary for its decomposition from the exhaust heat gas C of the gas turbine in the fuel processing reactor 7''b (CO+ 2H2). It is decomposed into a mixed gas with increased thermal energy and is supplied to the gas turbine system.Therefore, the turbine output e obtained from the gas turbine power generation system l increases.On the other hand, the steam turbine power generation Although the amount of energy converted into effective energy in system E decreases and the Rankine turbine output f decreases, the power generation efficiency of the gas turbine power generation system is higher than that of the steam turbine power generation system, and Since a two-turbine turbine power generation system 102 is added, the overall power generation efficiency is improved.1.It is possible to increase the turbine output.In addition, the amount of waste energy released into the atmosphere is approximately Even if the output is the same, the total power generation amount in the combined power generation system according to this embodiment will increase.

Therefore, considering the total power generation amount and power generation efficiency, let F be the amount of fuel input converted into heat amount, and let P be the input heat amount at the inlet of the gas turbine 2a, in the conventional system, F and P are equal. And gas turbine 2a
When the amount of waste heat energy is Q, the following relationship holds true: F=P=L, +W, +Q. In addition, the loss in the steam cycle is L
2. Letting the steam turbine output be W2, there is the following relationship: Q=L2+W2. Therefore, assuming that the loss coefficient in the gas turbine 2a is C5, the power generation efficiency is η3, and the power generation efficiency in the steam turbine 4 & is η, =tg-P W, =ηg-p Q =P・(1-ε , -η,) L2=P・(1-6g”g)・(1−η,)w=p・(
1-ε, -ηg)・η8, so the total generated energy amount W is W=W1+
W2 =P・η, +P(1−ε, −ηg)・η.

given as. For example, ε=0. O15η,=0.3
34 η, = 0.23, then W = 0.484·P, and the total power generation efficiency η is η = W/FX100% = 48.4 h.

On the other hand, according to the combined power generation system according to the present embodiment, a part R of the exhaust heat energy of the gas turbine 2a is recovered to increase the energy of the heating material a' at the inlet of the gas turbine 2a. F+R: Given as P+R. Each energy at this time is L1=ε, ・p'=ε, ・(p+R)>L.

W'=7sp'=ri, (P+R) g =w, +η, ・R)W.

Therefore, although the gas loss L1 in the turbine 2m increases slightly, the turbine output W increases further. Then, the inlet heat amount S in the steam turbine power generation system l
is the heat tQJ decrease in the conventional system, S=Q'-R=p'-(1-7g-1g)-R=(F+
R)-(1-4,-g,)-R=F・(1-vg-ri)
−R(η, +εg)=Q−R・(η,−)4g)<Q. Also, here, w; = s・η, =F' −(t-gg−ηgX1−ηg)−u・(gg
+η, )-(x-ηg)=W2-R・(ε,+η,)・
(1-η,)〈w2. However, η,=1−η.

Next, for the turbine power generation system 102, T=S-W flea=F・(1-g,-vg)(1-ηg)-R-(ε1
+ηg)・(t−?s)W′3=T・ηb=F・(1−ε,−1)・(1−η.)・ηb−R(ε
2+η, )・(1−η3)・ηb. Therefore, the total amount of energy generated by the total system is ηb=0.0
4, w' == w', +w'2+w'3=F
・(η, +(1-ε,-ηg)"7g+(I Ig-η
g)・(1−η,)・ηb) 10R・(η, −(ε, +9
g)・η8−(ε,+η,)・(1−1m)・ηb)=
W+(1””4g−η, )・(1−ηg)・ηb+R・
(η, −(ε, +η,)・η8−(ε, +9g)・(1
-η, )・ηb)=W+0.02XF+0.24XR.

Here, if R=0.27F, W'=W+ 0.09 F = (0,484+ 0.09) X F=0.05
74XF, its total power generation efficiency η' is η'=W/FX 100chi=57.4chi. By the way, η' - η = 9chi, which gives an overall power generation efficiency of about 18% increase (9chi in absolute value).

Furthermore, by improving the performance of the gas turbine 2a, η□=0.
4, η and η' become η=53.4chi and η'=64.7chi, assuming that other conditions are the same as the above conditions.

As a result, a high total power generation efficiency of 11.3 m in absolute value was achieved, and the total power generation efficiency reached 64.7%.

Note that the present invention is not limited to the above embodiments. For example, only methanol is used as heating material a, ethanol,
Alcohols such as butanol, methane (CH4: L
The main component of NG vaporized gas), propane, butane, naphtha, and other hydrocarbons can also be used. Also, when using methane: by adding H20 (water or steam) as a second chemical reactant, the
Under conditions of ~20 atmospheres, it is possible to cause an endothermic reaction in which the main reaction is CH4+H20→CO+3H2, and a nickel-based catalyst can be used.

Further, in the above embodiment, steam (Rankine) turbine system equipment such as the feed water preheater 3b1 and steam generator 30, and chemical reaction system equipment such as the fuel preheater 101a and the fuel processing reactor 101b are installed in the flue 3a. Although an example in which they are arranged in a mixed manner is shown, the present invention is not limited to this, and the flue 3a is branched, and the steam (Rankine) turbine system equipment is placed on one side, and the chemical reaction system equipment is placed on the other side. A similar effect can be obtained by a parallel arrangement method in which the elements are arranged in parallel.

Further, a fuel preheater 101a and a fuel processing reactor 101
b is provided outside the flue 3&, and these, the fuel preheater 10
1 m, a so-called indirect heat exchange method may be used in which a suitable heat medium is used to connect the fuel processing reactor 1101b and the exhaust heat generator.

Furthermore, in the embodiment described above, the Rankine turbine power generation system is subordinately connected to the "downstream" region of the steam turbine power generation system f, but these are arranged in the same position and are controlled according to their respective operating temperature ranges. A system may also be used in which heat is recovered from the exhaust gas flow within the flue 3IL. The present invention is not limited to application to power generation plants, but can also be applied to systems using gas turbines as the main engine of ships, etc., and can also be widely used in general industrial gas turbine power units, etc. .

[Brief explanation of drawings]

Figures 1 to 4 show a system according to an embodiment of the present invention. Figure 1 is a block diagram showing its schematic configuration, Figure 2 is a system configuration diagram, and Figure 3 shows the energy input/output relationship. FIG. 4 is a schematic diagram showing the amount of heat produced by combustion of fuel, FIGS. 5 to 7 are diagrams showing conventional examples, FIG. 5 is a block diagram showing the schematic configuration, and FIG. is a system configuration diagram, and FIG. 7 is a schematic diagram showing the energy input/output relationship. 1...Combustor, l...Gas turbine power generation system, 2&...
... Gas turbine, 2b... Generator, Mutual... Exhaust heat boiler system, 3a... Flue, 3b... Water supply preheater, 3C
...Steam generator! ...Steam (Rankine) turbine power generation system, 4m...Steam (Rankin) turbine, 4b.
... Generator, 5... Condenser, 6... Cooling water pump,
101a... Fuel preheater, 101b... Fuel vaporizer, 102... Rankine turbine power generation system, 102m...
・Rankin turbine, 104c...heat exchanger, 104
d...Steam (working fluid) pump. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 3 (in cavrnot) Figure 4 Figure 5 Figure 7

Claims (1)

[Claims] It is equipped with a gas turbine and a multiple Rankine turbine system that is driven by exhaust heat energy from the gas turbine and uses two or more types of working fluids, and is one of the fuels to be supplied to the gas turbine or the fuel to which a reactant has been added. A part or all of the waste heat energy of the gas turbine is chemically reacted using a part of the exhaust heat energy, and the fuel is converted into a secondary fuel with higher combustion energy and supplied to the gas turbine, and the multiple Rankine turbine system A combined power generation system characterized by multiple recovery of a portion of the exhaust heat energy from the gas turbine.