JPH10160110A - Power generation plant combined with refuse incineration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide power generation plant combined with refuse incineration which achieves a higher heat efficiency of the plant as a whole by improving the heat efficiency of a heater in an attempt to overcome failure in successfully upgrading the heat efficiency of the plant because of worse heat efficiency of the heater in the conventional garbage incineration power generation plant in which the upgrading of a turbine efficiency is made by using a superheating part alone for the heater for heating steam from a waste heat boiler. SOLUTION: Steam generated by a waste heat boiler 2 is heated by a heater 4 to raise the temperature thereof and the steam heated up to a higher temperature is supplied to a steam turbine 6 to drive the steam turbine 6. Thereafter, an exhaust discharged from the steam turbine 6 or the steam extracted from a step in the course of the steam turbine 6 is returned to the heater 4 again for reheating. The steam reheated up to a higher temperature is supplied to the steam turbine 6 to drive the steam turbine 6. This achieves a higher heat efficiency of the heater 4 thereby improving the efficiency as plant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refuse incineration power plant in which waste heat generated in a refuse incinerator is recovered by a waste heat boiler and generated using steam, and more particularly, to a waste incineration power plant. The steam generated by the heat boiler is provided independently of the waste heat boiler, and is overheated by a heater that burns and heats external fuel such as city gas, or is supplied to a steam turbine by heating. The present invention relates to a refuse incineration power plant that generates power.

[0002]

2. Description of the Related Art Waste incineration power plants that generate electric power by utilizing waste heat generated in association with waste incineration in waste incinerators have been constructed and started to operate in various places.
Such garbage to be incinerated in a garbage incinerator contains various miscellaneous things, so if the combustion temperature is increased, the damage to the garbage incinerator will progress significantly, Due to the generation of harmful substances such as dioxin, the temperature of the combustion gas is kept lower than that of an industrial boiler plant that generates steam by burning only a specific fuel such as gas or oil. On the other hand, when a low-temperature, low-pressure steam is used for the steam turbine that drives the generator, the turbine efficiency deteriorates, and there is a problem that a high-efficiency waste incineration power plant cannot be realized.

[0003] For this reason, in a conventional refuse incineration power plant, steam generated by collecting waste heat generated in a refuse incinerator by a waste heat boiler is provided independently of the waste heat boiler. An external fuel such as gas is burned, and overheated or heated (hereinafter, also simply referred to as heating) by a heater that heats the combustion gas. There is a refuse incineration power plant that can generate power with high efficiency.

FIG. 3 shows such high-efficiency power generation.
Of a conventional waste incineration power plant
FIG. Incinerate the collected garbage as shown in the figure
Exhaust gas G generated in rubbish incinerator 01 ₁Is a waste heat boiler
02, and the waste heat in the exhaust gas is
Collected to generate steam S.

The steam S is provided via a main steam line 03 independently of the above-described waste incinerator 01 or the waste heat boiler 02, and is provided with a fuel supply source 0 storing city gas and the like.
7 or a superheated portion 05 of a heater 04 which is heated by the combustion gas of the fuel F supplied directly from a city gas pipe, and after raising the temperature, is guided to a steam turbine 06 to generate power (not shown). Turbine 06 coupled to the machine
To generate electricity. Also, feed water W that generates steam S
Is configured to supply the stored water W by condensing the exhaust gas discharged from the steam turbine 06 with a condenser not shown in the drawing, from the water supply tank 08 to the waste heat boiler 02 via the water supply pump 09. I have.

Further, the exhaust gas G _{1, which} has heated the feed water W in the waste heat boiler 02 to generate the steam S, is subjected to exhaust gas treatment in the same manner as in a normal refuse incineration plant, and then the chimney 01
Emitted from 0 to the atmosphere. In addition, fuel F such as city gas
The flue gas G ₂ after the temperature of the steam S introduced from the waste heat boiler 02 is increased by the flue gas G ₂ is subjected to flue gas treatment in the same manner as the flue gas G ₁ , Released to

[0007] In such a waste incineration power plant,
As described above, instead of supplying the steam S generated by the waste heat boiler 02 to the steam turbine 06 as it is to generate power, the temperature of the steam S is increased by the heater 04 and supplied to the steam turbine 06. Therefore, the turbine efficiency is improved, the thermal efficiency of the entire incineration power plant is increased, and a waste incineration power plant capable of performing high-efficiency power generation can be provided.

[0008] However, in the above-mentioned conventional refuse incineration power plant, the heater S in which the steam S from the waste heat boiler 02 is superheated by the combustion gas of the external fuel F such as city gas, heats the steam S. Exhaust gas G heated in section 05
₂ is to release it to the atmosphere as it is,
There was a problem that the use of the external fuel F was not efficient.

[0009] That is, as shown in FIG. 4 showing the fluid temperature inside the superheater 05, the combustion gas temperature of the fuel F which is burned in the superheater 05 by G ₂ T ₂ decreases from G ₂ T ₁ , the temperature of the steam introduced to the superheated portion 05 through a main steam line 03 rises from ST ₁ to ST _2. For this purpose, the temperature G ₂ T ₂ of the exhaust gas G ₂ heating the steam S
Is never drops below the temperature ST ₂ of the steam S that has been heated by the heating unit 05, will be discharged to the atmosphere remain hot. Incidentally, the temperature of the exhaust gas G ₂ emitted to the atmosphere from the heater 04 is also approximately 300 ° C. to 350 ° C., in terms of the use of external fuel F, there is a problem of effective utilization of heat is insufficient Was.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional refuse incineration power plant by reheating the steam supplied to the steam turbine and driving the steam turbine, and reheating the steam from the heater. An object of the present invention is to provide a refuse incineration power plant that lowers the temperature of exhaust gas discharged to the atmosphere and discharges the exhaust gas to the atmosphere, thereby effectively utilizing heat and generating electric power with higher efficiency.

[0011]

Therefore, the refuse incineration power plant of the present invention has the following means. In garbage incinerator,
Waste heat generated by incineration of garbage is recovered by a waste heat boiler to generate steam, and this steam is provided independently of the refuse incinerator and waste heat boiler, and is generated by the combustion gas of external fuel such as city gas. In a refuse incineration power plant that raises the temperature with a heating heater and supplies the heated steam to a steam turbine to generate power, the exhaust gas discharged from the steam turbine, or from the middle stage of the steam turbine The steam to be extracted was returned to the heater again to be reheated, and the reheated and heated steam was again supplied to the steam turbine to drive the steam turbine.

In the refuse incineration power plant according to the present invention, the exhaust gas which has been discharged into the atmosphere at a high temperature from the heater by the above-mentioned means is supplied to the steam turbine having a low thermal energy (temperature) returned from the steam turbine. The heat is exchanged with the exhaust gas or the extracted steam, so that the temperature is lowered to be released into the atmosphere. Also, heat exchange with exhaust gas increases heat energy,
The exhaust or extracted steam returned to the steam turbine is further returned to the steam turbine to drive the steam turbine.

That is, in a heater installed in a conventional refuse incineration power plant, as shown in zone A of FIG. 2, the heater was guided from a waste heat boiler to a heater (superheater) via a main steam line. the temperature of the vapor, to raise from ST ₁ to ST _2, the combustion gas temperature of the fuel F is burned in heater G ₂ T ₂ decreases from G ₂ T _1, the temperature G of the exhaust gas G ₂ discharged ₂ T ₂ is the temperature of the steam heated by the heater S
Those it was impossible to lower than T ₂ is the exhaust from the steam turbine, or the temperature ST ₃ the extraction steam S
To the so increased to T _4, the heater waste incineration power plant of the present invention, it is possible to reduce the G ₂ T ₂ to G ₂ T _3.

This means that the temperature of the exhaust gas G ₂ is reduced to G ₂ T ₂
To G ₂ T ₃ and reduce the temperature from ST ₃ to ST ₄
The waste incineration power plant according to the present invention has a higher efficiency than the conventional waste incineration power plant by the amount of the exhaust gas that is supplied again to the steam turbine and drives the steam turbine or the driving force of the extracted steam. Has been improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a refuse incineration power plant according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of a waste incineration power plant according to the present invention.

As shown in the figure, a high-temperature exhaust gas G ₁ generated in a refuse incinerator 1 for incinerating collected refuse is introduced into a waste heat boiler 2, and waste heat in the waste gas is discharged from the waste heat boiler 2. is recovered, the steam S temperature ST ₁ is generated. This steam S
Is heated through a main steam line 3 by heating the city gas by a superheater 5 of a heater 4 provided independently of the refuse incinerator 1 or the waste heat boiler 2 described above. ST
_After being raised to ₂ , the steam is supplied to the steam turbine 6 and drives the steam turbine 6 connected to the generator 11 to generate power.

As described above, the steam turbine 6 is driven and S
The temperature of the steam S extracted from the steam turbine 6 decreases to T ₃ , and is again introduced into the reheating unit 12 of the heater 4, and the temperature of the steam S is increased from ST ₁ to ST _2. temperature is lowered from ₂ T ₁ to G ₂ T _2, it is reheated by combustion gas city gas. The reheat steam that is heated from ST ₃ in the heater 4 to the ST ₄ is again supplied to the steam turbine 6 again to drive the steam turbine 6. Further, the exhaust that drives the steam 6 and is exhausted from the steam turbine 6 is introduced into the condenser 13 and is condensed to be condensed.

Further, the steam required for the incineration plant is
Bleed air 10 is extracted from the steam turbine 6 at a required pressure, and supplied to equipment that requires steam S via an extraction line 14. In the above-described embodiment, the steam introduced into the reheating unit 12 of the heater 6 is the extracted steam extracted by the steam turbine 6, but a part of the exhaust gas of the steam turbine 6 may be introduced. Things.

Next, the condensed water condensed in the condenser 13 is supplied to
Including water condensing pump 15 and water supply pump 9 as water W,
Is supplied to the waste heat boiler 2 through another water supply facility. Ma
Introduced into the waste heat boiler 2 to heat the feed water W
Exhaust gas G which generated ₁Is subject to exhaust gas treatment as before
After being released, it is released from the chimney 10 into the atmosphere. Also city
The gas burns, and the steam S introduced from the waste heat boiler 2
And the temperature of the reheated steam returned from the steam turbine 6
Exhaust gas G raised_TwoIs exhaust gas G₁Exhaust gas treatment as well
Is released to the atmosphere by the chimney 10.

FIG. 2 is an explanatory diagram of fluid temperatures of steam and combustion gas in the above-described waste incineration power plant according to the present embodiment. In the figure, the vertical axis indicates temperature,
The horizontal axis indicates the site. That is, part A shows the superheated part 5 shown in FIG. 1 and part B shows the reheat part 12. In the section A, G ₂ T ₁ is the inlet gas temperature of the superheater 5, that is, the temperature of the fuel gas obtained by burning the city gas at the inlet of the superheater 5, and G ₂ T ₂ is the combustion gas temperature at the outlet of the superheater 5. ,
ST ₁ is a superheater 5 for the steam S supplied from the waste heat boiler 2
Temperature at the inlet, ST ₂ represents the temperature of the steam S at the outlet of the superheater 5, respectively, the steam S that has been superheated by the superheating unit 5, indicates that wither Shirubebi the steam turbine 6 becomes temperature ST ₂ I have.

In general, the heat is transferred by a heat exchanger such as the heater 4.
When heat is applied, there is a structural heat transfer limit (pinch
Point ΔT), the gas side temperature G_TwoT_TwoIs the steam temperature
Degree ST_Two+ ΔT. Therefore, the heating shown in FIG.
In the case of heat exchange only in the superheated section 05 as in the vessel 04, FIG.
As shown, this temperature G_TwoT_TwoExhaust gas G_TwoIs as it is
Although released to the atmosphere, the waste incineration power generation
, The temperature ST from the steam turbine 6_ThreeBleed steam
Then, the heater 4 was returned to the reheating section 12 again.
As a result, the steam S reaches the temperature ST as shown in part B._ThreeFrom
ST_FourHeated until. The combustion gas is G_TwoT_TwoFrom
G_TwoT_ThreeHeat recovery. This G_TwoT_ThreeAlso
G_TwoT_TwoReheat with the addition of the pinch point ΔT
Steam ST _FourWill be determined.

[0022]

As described above, according to the refuse incineration power plant of the present invention, the configuration shown in the claims makes it possible to improve the efficiency of the plant by using a device installed separately from the refuse incineration device. Effective utilization of fuel supplied from the outside can be measured, and the thermal efficiency can be further improved as compared with a conventional refuse incineration power plant.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a waste incineration power plant according to the present invention;

FIG. 2 is a view showing a fluid temperature in the heater shown in FIG. 1;

FIG. 3 is a block diagram showing a conventional refuse incineration power plant.

FIG. 4 is a diagram showing a fluid temperature in the heater shown in FIG. 3;

[Explanation of symbols]

 1,01 Waste incinerator 2,02 Waste heat boiler 3,03 Main steam line 4,04 Heater 5,05 Superheater 6,06 Steam turbine 7,07 City gas (fuel supply source) 8,08 Condenser ( Water supply tank) 9,09 Water supply pump 10,010 Chimney 11 Generator 12 (Heating device) Reheat unit 13 Condenser 14 Extraction line 15 Condensate pump

Claims (1)

[Claims] 1. A steam generated by a waste heat boiler for recovering waste heat generated in a refuse incinerator is independently installed, heated by a heater for burning external fuel, and connected to a generator. In a refuse incineration power plant that is supplied to and driven by a steam turbine, steam extracted from the steam turbine or steam discharged from the steam turbine is reheated by the heater and supplied to the steam turbine. A refuse incineration power plant characterized in that: