JP2987127B2 - Combined power generation system using waste as fuel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined power generation system using waste as fuel for recovering power from a high-temperature corrosive combustion gas by a heat exchanger, an air compressor, an air expansion turbine, and a steam turbine.

[0002]

2. Description of the Related Art Instead of a power generation system using a Rankine cycle using water-steam, a carina cycle using an ammonia-water mixed fluid is expected to contribute to improving the efficiency of the power generation system. By using the Karina cycle as the bottoming cycle of the open gas turbine, the output of the steam turbine is said to be about 25% higher than the steam turbine output of the reheat regeneration Rankine cycle. As a result, the power generation efficiency (lower calorific value conversion) of the commercial gas turbine combined cycle using natural gas as fuel is expected to reach about 60%.

On the other hand, in waste power generation, the combustion gas is corrosive, and the temperature of waste heat recovery steam is kept low at 300 ° C. in Japan. An open gas turbine that uses natural gas as fuel along with a waste incinerator is installed, and the method of reheating waste heat recovery steam from the incinerator with clean exhaust gas from the gas turbine is based on the efficiency of the Rankine cycle and the Kalina cycle. It will be improved. However, this method requires additional fuel, such as natural gas, in addition to waste.

[0004] In addition, a method of making recovered steam high temperature and high pressure is as follows.
The heating tube must be replaced periodically according to the corrosion,
There is a problem that it is necessary to accurately predict the replacement time and that the number of days required for the replacement reduces the operation time of the power generation and the waste disposal.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and is intended to improve the power generation efficiency without using an additional fuel such as natural gas. It is an object of the present invention to provide a combined power generation system using as fuel. The applicant of the present application has previously filed Japanese Patent Application No. 8-31412.
In the issue, "combined power generation system using waste as fuel"
In this system, a high efficiency is obtained by combining a closed cycle gas turbine using corrosive exhaust gas as a heat source and a carina cycle.However, heat exchange between corrosive exhaust gas and an ammonia-water mixed fluid is required. Was needed. Waste incineration facilities installed in urban areas require further safety against ammonia leak accidents.

[0006]

The combined power generation system of the present invention comprises a heat exchanger, a clean air compressor, an expansion turbine, and a carina cycle steam turbine, and waste combustion waste gas exchanges heat with clean air. Heat is recovered only by the heat exchanger to be used. The outlet temperature of the clean air compressor is set to a temperature slightly lower than the minimum waste gas recovery temperature of 150 ° C. by an intercooler cooled with an ammonia-water mixed fluid. The clean air heated by the waste gas recovers power by the expansion turbine, and the exhaust gas at the outlet of the expansion turbine becomes a heat source of the carina cycle. Since the heat recovered by the intercooler of the compressor is also used as the heat source for the Kalina cycle, the efficiency of the combined cycle is not changed. Further, by providing the compressor with an intercooler, the power of the compressor is also reduced. An intercooler of the compressor can be provided at the outlet of the high-pressure compressor to simplify the compressor casing structure.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. The numerical values given in the present embodiment are merely examples, and are not limited to these. FIG. 1 is a system diagram of a combined cycle power generation system according to the present invention. In FIG. 1, reference numeral 1 denotes high-temperature exhaust gas from a waste incinerator, and reference numeral 2 denotes clean air. The combined power generation system includes a heating heat exchanger 3, a low-pressure compressor 4, a high-pressure compressor 5, an expansion turbine 6, and an ammonia-water mixed fluid steam turbine 7.
And a generator 13. Further, the combined power generation system includes an intercooler 8, a heat exchanger 9, and a heat exchanger 10
And a carina distillation condensing system 12.

In the above configuration, the waste flue gas 1
Converts the clean air 2 by the heating heat exchanger 3 into the low-pressure compressor 4.
And the air pressurized by the high-pressure compressor 5 is cooled to recover waste heat. The clean air 2 heated by the heat exchanger 3 is expanded by the expansion turbine 6 and drives the generator 13 to recover power.

The ammonia-water mixed fluid 11 is supplied to the heat exchanger 9
Thus, the heat is evaporated and heated by the exhaust heat of the expansion turbine 6. The heated ammonia-water mixed fluid 11 expands in the ammonia-water mixed fluid steam turbine 7 and power is recovered.

The exhaust gas of the ammonia-water mixed fluid steam turbine 7 is liquefied by a carina distillation / condensation system 12, and is evacuated and heated by an intercooler 8 of a compressor and downstream of the heat exchanger 9. The heat is divided into flows to be heated by evaporation in the arranged heat exchanger 10, merges again at the inlet of the heat exchanger 9, and flows into the heat exchanger 9.

In the combined power generation system, the corrosive exhaust gas source is a high-temperature exhaust gas from a waste incinerator, and the temperature of the exhaust gas 1 depends on the air ratio of the incinerator combustion.
It is in the range of 50 ° C. In the present embodiment, the daily amount is 3
There is a waste incinerator of 00 tons, and the amount of exhaust gas is 110t /
h, description will be made assuming that an exhaust gas temperature of 1350 ° C. is given.

In the low-pressure compressor 4, the inlet air flow rate 24
0t / h, inlet temperature 15 ° C, inlet pressure 0.102MP
a. abs, and the outlet pressure was 0.21 MPa. abs,
If the number of rotations is 5000 rpm, the outlet temperature is 121 ° C.
The required power is 5.6 MW. In the high-pressure compressor 5,
Inlet air flow rate 240 t / h, inlet temperature 70 ° C, inlet pressure 0.209 MPa. abs, outlet pressure 0.35M
Pa. Assuming that the abs is 5000 rpm, the outlet temperature is 130 ° C. and the required power is 3.4 MW. The inlet air of the high-pressure compressor 5 is cooled by the intercooler 8 from 121 ° C. to 70 ° C.

In a heating heat exchanger 3, clean air 2 pressurized by a compressor with high-temperature exhaust gas 1 at 1350 ° C.
Heat from 30 ° C to 742 ° C. The heating heat exchanger 3 is divided into a radiant heat transfer section and a convection heat transfer section, and the radiant heat transfer section is covered with a refractory material that protects the metal heat exchanger. As the convection heat transfer section, a panel-shaped heat exchanger is used which is parallel to the exhaust gas flow in which the deposition of molten salt contained in the waste combustion gas is difficult to deposit and grow.

In the expansion turbine 6, the inlet pressure is 0.3
3 MPa. abs, the inlet temperature was 742 ° C., and the outlet pressure was 0.106 MPa. Assuming that the abs is 3000 rpm, the outlet temperature is 512 ° C. and the recovery power is 18 MW. If this air expansion turbine 6 is diverted from the output turbine of a commercial two-shaft gas turbine, high efficiency can be obtained.

In the ammonia-water mixed fluid steam turbine 7, an inlet pressure of 10.0 MPa. abs, inlet temperature 4
90 ° C., and the ammonia-water mixed fluid is ammonia 70
% Water 30%. Assuming that the flow rate of the ammonia-water mixed fluid is 40 t / h, which is expanded and the adiabatic efficiency of the turbine is 86%, the outlet pressure is 0.15 MPa · ab.
s, the outlet temperature is 86 ° C., and the recovery power is 11 MW.

The intercooler 8 of the compressor employs a shell and tube system. The cooling medium is the ammonia-water mixed fluid 11 of the carina cycle. In the heat exchanger 9, the expansion turbine exhaust and the ammonia-water mixed fluid 1
The heat exchanger 9 performs heat exchange with the heat exchanger 9 using a serrated fin tube. The heat exchanger 10 is a heat exchanger 9
And heat exchange between the expansion turbine exhaust and the ammonia-water mixed fluid 11. The heat exchanger 10 uses a serrated fin tube. If the final outlet temperature of the clean air is 70 ° C., the relationship between the recovered heat and the heat exchanger heat transfer area is optimal.

The recovery power of the embodiment described above is the difference between the power consumption of the compressor based on the sum of the recovery power of the expansion turbine and the recovery power of the ammonia-water mixed fluid steam turbine.
MW power recovery. When the total of the reduction gear loss and the generator loss between the expansion turbine 6, the steam turbine 7, and the generator 13 is subtracted, the power generation end output is 18.6 MW.

Assuming that waste heat of waste gas is recovered from 1350 ° C. to 150 ° C., the recovered heat quantity is 46.3M.
Wth. The combined thermal efficiency as a percentage of the recovered heat of 18.6 MW of power generation end was 40.2%, and the output was 20 M
High efficiency comparable to W-class natural gas-fired combined cycle efficiency can be obtained. Carina cycle alone 34% at 20MW class
Therefore, it was proved that the efficiency was sufficiently improved.

[0019]

As described above, the present invention has the following effects. (1) Compared to the conventional steam turbine system, a combined power generation system that recovers power from waste combustion high-temperature combustion gas by Brayton cycle and recovers power from gas turbine exhaust and low-temperature combustion gas by Kalina cycle is constructed. Large output increase can be expected. Steam temperature 300
The output of the conventional steam turbine system of ℃ is recovered heat 4
13.9 MW, which is 30% of 6.3 MWth, the output of the Kalina cycle is 20% higher than that of the Rankine cycle.
Assuming 6.7 MW, the combined power generation output of the present invention is 18.6 M
W provides 134% power increase over conventional steam turbine systems and 111% power increase over Kalina cycle.

(2) Even if the high-temperature gas heat exchanger for corrosive gas leaks due to corrosion, the pressure of the working fluid is 0.35 MPa. abs low-pressure air, 10 when high temperature and high pressure are achieved in a conventional Rankine cycle.
It is safer than the accident of steam explosion of MPa. In addition, the Carina Cycle uses ammonia as a heat recovery medium for the high-temperature gas heat exchanger of corrosive gas, but this use of ammonia poses anxiety to local residents of waste treatment facilities installed in urban areas. Heat recovery with exhaust gas-air with a low risk of ammonia leakage is preferred.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a combined power generation system using waste as fuel according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust gas 2 Clean air 3 Heating heat exchanger 4 Low pressure compressor 5 High pressure compressor 6 Expansion turbine 7 Ammonia-water mixed fluid steam turbine 8 Intercooler 9 Heat exchanger 10 Heat exchanger 11 Ammonia-water mixed fluid 12 Carina Distillation condensation system

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor ▲ Tsuru ▼ Katsuharu Maki 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (56) References JP-A-56-53316 (JP, A) JP-A-9-144507 (JP, A) JP-A-9-32513 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01K 25/10 F01K 25/00 F01K 27/02 F23G 5/46 ZAB

Claims (1)

(57) [Claims] 1. A and an exhaust gas source waste and fuel, and a heat exchanger for heating air by waste gas, a low pressure compressor and a high pressure compressor for compressing air, and the low-pressure compressor high-pressure
An intercooler provided between the compressors, an expansion turbine for expanding heated air, and a carina cycle steam turbine, and the exhaust of the expansion turbine evaporates and heats the ammonia-water mixed fluid of the carina cycle. Equipped with heat exchanger, front
Serial during cooler heat the Kalina cycle ammonia -
Recover with water mixed fluid, evaporate ammonia-water mixed fluid
A combined power generation system using waste as fuel, characterized by evaporating and heating an ammonia-water mixed fluid of a carina cycle by a heat exchanger disposed downstream of a heat exchanger to be heated.