JPH11294111A - Power generation method for refuse incineration and independent superheater used for the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surplus BF for supplying steam to a steam turbine while preventing high-temperature corrosion of a boiler tube due to chlorine.
An object of the present invention is to increase the amount of power generation by using G to achieve high temperature and high pressure with a simple configuration. SOLUTION: After high-pressure and medium-temperature saturated steam overheated by a boiler of a refuse incinerator is heated by a heat storage body that stores heat with BFG combustion gas from the blast furnace, and is overheated by a heat storage type independent superheater that burns BFG. Supplying power to turbines to generate power

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-temperature, high-pressure saturated steam generated from a refuse incinerator at about 300 ° C., which is superheated to a high-temperature, high-pressure steam by an independent superheater using a compact and highly efficient BFG. The present invention relates to a waste power generation system using BFG for performing high-efficiency power generation.

[0002]

2. Description of the Related Art As shown in FIG. 5, a conventional refuse incineration power generator uses a high-pressure power generated by an incinerator boiler 1 for incinerating garbage.
The steam turbine generator 3 generates electric power with medium-temperature steam. The condensate discharged from the steam turbine passes through a condenser 4, and the extracted water is directly guided to a deaerator 5, and is returned to an incinerator boiler 1 via a feedwater pump 6. This conventional waste heat boiler of a waste incinerator has a steam temperature of 300 ° C. or less in a superheat section (superheater), and a power generation efficiency of 10 ° C.
It was as low as a few percent. This is because garbage includes various types of plastics as well as paper and garbage, as well as plastics, and furnaces and boilers are subject to various restrictions depending on the properties of fly ash and exhaust gas generated by their combustion. . That is, as the boiler tube, a low-cost carbon steel tube is mainly used, and in the relation between the tube wall temperature of the boiler tube and the corrosion rate, high-temperature corrosion starts at a tube wall temperature of 330 ° C. or more. The garbage used in the refuse incinerator is, as described above, chlorine contained in municipal waste waste, which is contained in vinyl chloride, plastic, etc., is converted into hydrochloric acid (HCl) by combustion, and the steam installed downstream of the incinerator It acts on the tube of the boiler for generation and corrodes it. Therefore, in order to avoid high-temperature corrosion damage, the steam temperature in the waste incinerator exhaust heat boiler and the superheat section (superheater) is suppressed to 300 ° C or less, and the power generation efficiency by conventional waste incineration is 15% or less. Therefore, using heavy oil or LNG as fuel, and boiler tube temperature of 500 ~
The power generation efficiency is significantly lower than the power generation efficiency of a plant that can be set to 600 ° C., and improvement thereof has been strongly desired.

Under such circumstances, increasing the pressure and temperature of steam is the most efficient means of increasing the efficiency in steam turbine power generation. Therefore, in order to increase the power generation efficiency by increasing the steam temperature, a technique has been studied to improve the corrosion resistance of the material of the superheat portion and to increase the temperature of the steam (Japanese Patent Application Laid-Open No. H8-120392). Alternatively, pyrolysis gas containing chlorine, which is a corrosive component, is completely combusted with air from refuse, and the energy of the pyrolysis gas is used as a medium temperature steam (30%).
(See Japanese Patent Application Laid-Open No. 8-80), in which a two-stage boiler combustion method is used in which a char mixture from refuse is burned and heated to superheated steam.
No. 233201).

[0004]

The most efficient means of increasing the power generation efficiency of a waste power generation system is to increase the steam temperature and pressure at the steam turbine inlet. That is, it is necessary to solve the problem of extracting high-temperature and high-pressure steam without promoting corrosion of the heat transfer tube. Although there is a technology to improve the material of the superheat part, high cost and high temperature and high pressure are not always sufficient, and the technology to completely burn the pyrolysis gas containing chlorine with air is too large, It cannot be directly applied to the conventional refuse incinerator structure. On the other hand, in the steelmaking industry, if efficient utilization of surplus BFG, which is produced in large quantities during blast furnace operation, can be achieved, it will be useful for measures to prevent air emission. Therefore, in order to effectively use this BFG, it was decided to use it for power generation for garbage incineration. However, BFG is C as shown in Table 1.
O is a 23% low calorie gas and the adiabatic flame temperature is 1
The temperature is 280 ° C., and in normal combustion, it is extremely inefficient to convert the supplied steam of about 300 ° C. into high-temperature and high-pressure steam of 500 ° C. or more.

[0005]

[Table 1]

According to the present invention, the amount of power generation can be reduced by preventing excess steam from being supplied to a steam turbine and using a surplus BFG to increase the temperature and pressure in a simple configuration while preventing high-temperature corrosion of the boiler tube due to chlorine. The aim is to increase.

[0007]

The present invention has the following features in order to achieve the above-mentioned object. (1) The invention according to claim 1 is a regenerative storage independent superheat that burns BFG by heating a high-pressure medium-temperature saturated steam superheated in a boiler of a refuse incinerator by a heat storage body storing heat with BFG combustion gas from the blast furnace. This is a power generation method for incineration of refuse, characterized in that the power is supplied to a turbine after being overheated in a vessel. (2) The invention according to claim 2 is characterized in that the independent superheater according to (1) preheats BFG and combustion air to be used to 600 ° C. (3) In a garbage incineration power generation facility in which high-pressure, medium-temperature saturated steam superheated by a boiler of a refuse incinerator is heated by an independent superheater that burns BFG and then supplied to a turbine to generate power, the independent superheater is a casing. A plurality of pairs of heat storage switching combustion burners are provided in the body, and a superheat boiler tube is arranged between the burners. Each of the heat storage switching combustion burners serves as a fuel gas supply during combustion and serves as an exhaust pipe for non-combustion. An inner pipe, an outer pipe that becomes a pipe for supplying combustion air at the time of combustion, and a porous regenerator through which BFG, combustion air, or exhaust gas can pass are provided inside the inner pipe and the outer pipe, respectively. ,
Each inner pipe is connected to BFG as fuel via a switching valve,
The outer pipe is connected to combustion air A via a switching valve,
Each of the inner pipe and the outer pipe is an independent superheater used for power generation of refuse incineration, wherein each of the heat storage switching combustion burners is connected to an exhaust gas facility via a switching valve.

[0008] The present invention has a simple structure in which the design of an existing incinerator boiler is changed so much that only a separate independent superheater is added. This independent superheater has a relatively clean BFG. Burn and raise steam temperature from 300 ° C to 50
Heating to about 0 ° C. is because this independent superheater has a high output and can be easily heated. In addition, the independent superheater has a configuration in which the heat storage switching combustion burner provided in the housing has a heat storage body and serves both for combustion and exhaust of combustion gas. Accumulates the heat of the high-temperature exhaust gas and lowers the temperature of the exhaust gas.
G and combustion air are heated to generate a high-temperature flame and become a high-efficiency superheat source. The combustion air and BFG are heated up to 600 ° C.
Can be easily preheated with a compact heat exchanger, usually 1200
It is possible to increase the adiabatic flame temperature of about 500 ° C. by about 500 ° C., thereby facilitating heat input to steam by radiation and also enabling stable combustion of BFG.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of the present invention. Incinerator boiler 1 to incinerate garbage
Is superheated by the independent superheater 2 to generate high-temperature and high-pressure steam. The high-temperature and high-pressure steam is guided to the steam turbine generator 3 and used for power generation. On the other hand, the condensate discharged from the steam turbine is
Then, the extracted water is directly guided to the deaerator 5 and returned to the incinerator boiler 1 via the water supply pump 6.

Here, the configuration of the independent superheater 2 is shown in FIG. In the independent superheater 2, a plurality of pairs of heat storage switching combustion burners 8 a, 8 b, 8 c, and 8 d are arranged in a housing 7, and a superheat boiler tube 9 is arranged between the burners. Each heat storage switching type combustion burner 8a, 8b, 8c, 8d
Has a structure in which an inner pipe 10 serving as a pipe for exhaust gas and a pipe for supplying combustion air at the time of combustion are provided for supplying fuel gas during combustion and non-combustion during non-combustion. Further, inside the inner pipe 10 and the outer pipe 11, fuel gas,
A porous heat storage body 12 through which combustion air or exhaust gas can pass is provided. The inner pipe 10 has switching valves 13a, 13
b, 13c, and 13d, the outer pipe 11 is connected to the BFG serving as fuel, and is connected to the switching valves 14a, 14b, 14c, and 14
It is connected to combustion air A via d. Further, each inner pipe 10 and outer pipe 11 are provided with respective heat storage switching combustion burners 8.
a, 8b, 8c, 8d, switching valves 15a, 15b,
Each is connected to a chimney 17 via an exhaust gas pump 16 which is an exhaust gas facility via 15c and 15d.

Here, the operation of the independent superheater 2 will be briefly described. As shown in FIG. 2, the heat storage switching combustion burners 8a and 8d of the independent superheater 2 are used for combustion.
The case where b and 8c are used for heat storage will be described. The switching valves 13a and 13d are opened, and the switching valves 13b and 13c are closed (hereinafter, the switching valves are open in the drawings and closed in the drawings), and BFG is a heat storage switching combustion burner 8
a, 8d. Heat storage switching type combustion burners 8a, 8d
BFG coming out of the inner pipe 10 is a heat storage switching type combustion burner 8.
The superheated boiler tube 9 in the housing 7 is heated by being mixed with the combustion air A coming out of the outer tube 11a and 8d and burning in the housing 7 of the independent superheater 2. The burned high-temperature exhaust gas is discharged to the outside from the chimney 17 by the exhaust pump 16 via the inner pipe 10 and the outer pipe 11 of the heat storage switching combustion burners 8b and 8c and the switching valves 15b and 15c. At this time, the inner pipe 10 and the outer pipe 1 of the heat storage switching combustion burners 8b, 8c
1, a heat storage body 12 is provided, and an independent superheater 2 is provided.
The heat of the combustion gas combusted in the housing 7 is stored.

Next, the switching valves 13a and 13d are closed, and the switching valves 13b and 13c are opened (at this time, the switching valve 15
a, 15d are opened and the switching valves 15b, 15c are closed),
BFG is burned in the housing 7 of the independent superheater 2 via the heat storage switching combustion burners 8b and 8c. The exhaust gas is discharged from the chimney 17 to the outside by the exhaust pump 16 via the heat storage switching combustion burners 8a and 8d and the switching valves 15a and 15d. In this case, the boiler tube 9 for super heat is
Is performed in the same manner, but the heat storage switching combustion burners 8b and 8c, which have been switched once and stored heat, are supplied with the heat storage material 12 by the exhaust heat gas when the heat storage switching combustion burners 8a and 8d burn.
When BFG or combustion air A passes through the heat storage body 12, heat is taken from the heat storage body 12 to increase the temperature to increase the combustion temperature. The temperature of the BFG and the combustion air A itself becomes high, so that a high-temperature atmosphere can be generated, and the high-temperature state can be maintained while the superheating boiler tube 9 of the independent superheater 2 is stable. Hereinafter, the above cycle is repeated in several tens of seconds.

The sectional area ratio between the BFG of the heat storage switching type burner and the combustion air is set in accordance with the flow rate ratio. Further, when the BFG and the regenerator for combustion air are overheated by the exhaust gas, the switching time of the regenerator should be set so that both of the exhaust gas passing through the regenerator and exchanging heat become lower than a predetermined temperature (about 150 ° C.). And

[0014]

EXAMPLES Examples will be described below based on the examples shown in the above embodiments. FIG. 3 and FIG. 4 are diagrams showing the temperature distribution in the independent superheater 2. Incinerator boiler 1 to incinerate garbage
The high-pressure and medium-temperature steam (300 ° C., 88 ata) generated in the above is continuously supplied to the independent superheater 2 from the steam inlet 20 of the independent superheater 2 as saturated steam, and is supplied to the inside of the superheat boiler tube 9 in the independent superheater. Is heated mainly by radiant heat transfer from the high temperature calcined gas, and is taken out as superheated steam from the steam outlet 21 at a predetermined temperature of 520 ° C. and about 85 ata. The temperature in the independent superheater is 700 ° C. or higher, and the temperature Te of the exhaust gas guided to the heat storage body 12 of the heat storage switching combustion burners 8b and 8c during combustion by the heat storage switching combustion burners 8a and 8d also increases to about 700 ° C. . The maximum temperature of the heat storage body 12 is superheated to 650 ° C. by exchanging heat with the heat storage body 12 of the heat storage switching baking burners 8b and 8c which are not burning the energy of the exhaust gas (FIG. 4).

After several tens of seconds, the switching valves 13a, 13b, 13
c, 13d and switching valves 14a, 14b, 14c, 14d
And BFG is added to the heat storage switching type combustion burners 8b and 8c.
(25 ° C., 1.2 ata) Air for baking (25 ° C., 1.2 ata)
1.2 ata) is preheated to 600 ° C., respectively, and guided to the tip portion of the heat storage switching combustion burners 8 b and 8 c to ignite and burn. Heat storage body 12 of heat storage switching combustion burners 8a, 8d
As can be seen from the temperature distribution diagram of the heat storage body 12, the exhaust gas temperature of the exhaust gas outlet side (the left side in FIG. 4) is low, and from the exhaust gas outlet portion, linearly from 75 ° C. to 650 ° C.
And a predetermined value of 15 at the exhaust gas outlet side.
The temperature is 0 ° C. or less, which can avoid adversely affecting various exhaust gas facilities including the switching valve.

Here, assuming that the temperatures before and after the preheating of the BFG / combustion air A are 25 ° C. and 600 ° C. and the temperature of the exhaust gas is 700 ° C., the temperature efficiency as an index of the heat recovery rate is (600− 25) / (700-25) = 0.85. At this time, the fuel gas and the combustion air are preheated, resulting in significant energy savings and a heat recovery rate of about 85%. In this case, as shown in Table 2, the adiabatic flame temperature (Tf) becomes 1780 ° C., and the superheating potential increases by about 500 ° C., as shown in FIG. 3, as compared with the case where the fuel gas and combustion air are not preheated (1780− 700) / (1280-7)
00) = 1.86 times, the amount of heat input to the independent superheater 2 is reduced, and the heat transfer coefficient in the independent superheater 2 is improved. Therefore, by taking the above measures, it is possible to achieve energy saving and improvement of heat transfer efficiency by radiation by using low calorie BFG as a by-product gas of iron making, and to convert low calorie gas (BFG) into a gaseous combustible component (CO). Ignition temperature (6
By preheating to about 05 ° C), it was possible to stably burn.

[0017]

[Table 2]

[0018]

The present invention has the following effects.
According to the present invention, even in the case of incineration of municipal solid waste containing chlorine, it is possible to stably obtain superheated steam of about 520 ° C and 85ata using excess BFG while suppressing corrosion of boiler tube. By using this superheated steam to generate power in a condensing steam turbine, the conventional
A power generation efficiency of 20% or more was obtained. In addition, the configuration of the present invention can provide a compact waste power generation system that is simple and hardly changes a conventional waste incinerator, and has excellent effects.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a waste power generation method provided with an independent superheater of the present invention.

FIG. 2 is a schematic explanatory view showing an independent superheater used in the present invention.

FIG. 3 is an explanatory diagram showing a theoretical basis of the present invention.

FIG. 4 is an explanatory diagram showing an example of a temperature distribution in an independent superheater of the present invention.

FIG. 5 is an explanatory view showing a conventional waste power generation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incinerator boiler 2 Independent superheater 3 Steam turbine generator 4 Condenser 5 Deaerator 6 Water supply pump 7 Housing 8a-8d Heat storage switching type combustion par 9 Boiler tube 10 Inner tube 11 Outer tube 12 Heat storage body 13a-13d Switching valve 14a to 14d Switching valve 15a to 15d Switching valve 16 Exhaust gas pump 17 Chimney 20 Steam inlet 21 Steam outlet BFG Iron by-product gas A Combustion air Tf Adiabatic flame temperature Te Heat storage element inlet gas temperature Ts Steam temperature

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 7/06 ZAB F23G 7/06 ZABB

Claims (3)

[Claims] 1. A high-pressure, medium-temperature saturated steam superheated by a boiler of a refuse incinerator is converted into a steelmaking by-product gas (hereinafter "BFG") from the blast furnace.
B) which has been heated by the heat storage body that has stored heat with the combustion gas of
A power generation method for incineration of refuse, characterized in that the FG is supplied to a turbine after being overheated by a heat storage type independent superheater for burning FG. 2. The steelmaking by-product gas BF used for the independent superheater is used.
2. The power generation method for refuse incineration according to claim 1, wherein the preheating is performed at 600 [deg.] C. with G and combustion air. 3. A garbage incineration power generation facility in which high-pressure, medium-temperature saturated steam superheated by a boiler of a refuse incinerator is superheated by an independent superheater that burns BFG and then supplied to a turbine to generate electricity. A plurality of pairs of heat storage switching combustion burners are provided in the housing, and a superheat boiler tube is arranged between the burners.Each heat storage switching combustion burner is used for supplying fuel gas during combustion and exhaust piping for non-combustion. Inner heat pipe, an outer pipe which becomes a pipe for supplying combustion air during combustion, and a porous regenerator through which BFG, combustion air or exhaust gas can pass, respectively, inside the inner pipe and the outer pipe. Are provided, each inner pipe is connected to a BFG serving as fuel via a switching valve, the outer pipe is connected to combustion air A via a switching valve, and each inner pipe and the outer pipe are
An independent superheater used for power generation in garbage incineration, wherein each heat storage switching type combustion burner is connected to exhaust gas equipment via a switching valve.