JPH07243603A - Dust burning boiler - Google Patents

Abstract

PURPOSE:To effectually burn any dust by interposing an empty chamber constituting a passage for pressurized air between a combustion chamber and fresh air, and injecting the pressurized air into the combustion chamber. CONSTITUTION:An empty chamber 9 constituting a passage for pressurized air supplied to a combustion chamber 7 is interposed between the combustion chandler 7 is thermally insulated from the outside with the aid of the empty chamber 9, and any 985 passing through the inside of the empty chamber 9 is heated to permit combustion temperature in the combustion chamber 7 to be raised synergistically, resulting in increased radiation transfer mast effective for heat transfer. The pressurized air is injected into the combustion chamber 7 from many small holes 21 provided in an internal wall 8 so as to communicate with the empty chamber 9 and the combustion chamber 7. Hereby, oxygen is satisfactorily supplied to the interior of dust being matter to be burned, and the inside of the combustion chamber 7 is uniformly stirred. Thus, a heat transfer rate is improved and hence any dust is effectually burned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste fired boiler which heats water by utilizing heat generated when incinerating waste.

[0002]

2. Description of the Related Art Conventionally, refuse such as wood waste, paper waste and waste plastic has been simply burned in a refuse incinerator and discarded.
At this time, the combustion efficiency of ordinary waste incinerators is poor, and a large amount of smoke is generated due to incomplete combustion.Therefore, an auxiliary burner should be installed in the exhaust passage to further burn and purify the exhaust gas. Has become.

On the other hand, in recent years, from the viewpoint of resource saving, energy saving, and cost saving, it has been desired to develop a refuse-fired boiler that utilizes heat generated during incineration of refuse.

[0004]

However, the amount of heat generated by the combustion of waste in a general waste incinerator is lower than that of oil-fired boilers, etc., and the amount of heat generated by the combustion of waste in the waste incinerator as described above is There was a problem that the required amount of heat could not be obtained after heat exchange.

To solve the above problem, it is preferable to increase the heat exchange rate and / or the temperature in the combustion chamber. Therefore, for example, it is conceivable to provide the above-mentioned auxiliary burner in the combustion chamber to increase the amount of heat in the combustion chamber, but considering the complexity of waste treatment, fuel consumption, etc., resources and cost will be lower than those of ordinary boilers. It cannot be said that there is an advantage in terms of terms, and it is not very realistic.

It has also been proposed that the waste be finely crushed and then processed into a block of a desired size by using a cross-linking agent to be used as a solid fuel to increase the amount of heat in the combustion chamber. Is complicated, and the processing cost also rises. Therefore, even if such a solid fuel is used, a desired amount of heat cannot always be obtained in the combustion chamber, and an auxiliary burner or the like is eventually required, so much as above. Not realistic.

The present invention has been made in view of the above-mentioned problems of the prior art, and its main purpose is to efficiently combust dust without the need for auxiliary treatment and to combust the inside of the combustion chamber. (EN) It is possible to provide a dust-fired boiler that can obtain a very high amount of heat and that can efficiently exchange heat as a boiler.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned object is to provide an inner wall defining a combustion chamber and having a large number of water tubes for heat exchange, an outer wall surrounding the inner wall, and the inner wall. A chamber defined between the inner wall and the outer wall so as to substantially cover the outer surface of the chamber, an external pressurized air supply means connected to the chamber, and a heating chamber from the chamber toward the combustion chamber. It has a pressurized air injection port for injecting pressurized air and a dust inlet for throwing dust into the combustion chamber, and the pressurized air supplied from the pressurized air supply means is supplied to the inner wall outer periphery. A dust-fired boiler characterized by burning dust in the combustion chamber while injecting it from the pressurized air injection port into the combustion chamber through a void and heating the liquid in the water pipe with the combustion heat. Is achieved by providing.

[0009]

In this way, by interposing the vacant chamber forming the passage of the pressurized air supplied to the combustion chamber between the combustion chamber and the outside air, the combustion chamber is insulated from the outside by this vacant chamber and The gas passing through the chamber is heated, the combustion temperature in the combustion chamber is increased synergistically, the radiative heat transfer, which is the most efficient for heat transfer, is increased, and the heat transfer coefficient is dramatically improved. Further, by injecting pressurized air into the combustion chamber through a large number of small holes provided on the inner wall so that the vacant chamber and the combustion chamber communicate with each other, oxygen is sufficiently supplied to the inside of the combustion object, and Stir evenly. Further, the high temperature (100 ° C. or higher) pressurized air is extremely effective for dust with a large amount of moisture, and simultaneously causes drying and incineration to proceed. Further, by providing the above-mentioned many small holes in the heat absorbing fins between the water pipes forming the inner wall, the air in the combustion chamber which is very close to the surfaces of the water pipes and the heat absorbing fins where heat is exchanged is agitated to improve the heat transfer coefficient. You can

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partial cross-sectional view showing a schematic structure of a refuse-fired boiler to which the present invention is applied. This boiler has a combustion furnace main body 1 and a cyclone dust collector 3 connected to the combustion furnace main body 1 via an exhaust pipe 2. The dust collector 3 is provided with an ejector 4 for sucking the exhaust gas through the exhaust pipe 2 so that the downstream side of the combustion chamber, which will be described later, has a slightly negative pressure through the exhaust pipe 2 and guiding it to the chimney 5 through the exhaust pipe 2. Has been done.

The combustion furnace body 1 has a cylindrical inner wall 8 defining an internal combustion chamber 7 for burning dust, and an empty chamber 9 covering substantially the entire inner wall 8 between the outer peripheral surface of the inner wall 8. The defining outer wall 10, a downstream side of the combustion chamber 7, that is, an upper part of the combustion furnace main body 1 in the figure, which is provided with a dust inlet 11 and an ash outlet 12 that are open to the outside from the combustion chamber 7 are provided. Have Here, as also shown in FIG. 2, the inner wall 8 is composed of a large number of water pipes 14 and heat absorbing fins 15 provided between the water pipes 14. Each water pipe 14 is connected at its lower part to an annular distribution pipe 16. The distribution pipe 16 is connected to a water supply means (not shown) with a connection pipe 17. Further, each water pipe 14 is connected to the collecting pipe 18 at the upper part thereof. The collecting pipe 18 is connected via a discharge pipe 19 to a facility (not shown) that uses steam (not shown).

On the other hand, a blower 20 as an external pressurized air supply means is connected to the vacant chamber 9 via a damper 22 so as to supply pressurized air into the vacant chamber 9. The heat-absorbing fins 15 forming the inner wall 8 are provided with a number of small holes 21 as pressurized air injection ports at substantially equal intervals so as to connect the chamber 9 and the combustion chamber 7 to each other. The pressurized air thus obtained is supplied to the combustion chamber 7 through the small holes 21. Further, the blower 20 is connected to the ejector 4 via the damper 22.
Also, the downstream side of the combustion chamber 7 is made to have a negative pressure as described later.

The operating procedure of this embodiment will be described below. First, combustion is started in the combustion chamber by a predetermined ignition method, and at the same time, pressurized air is supplied from the blower 20. Then, the pressurized air passes through the empty chamber 9 and is sprayed from the small holes 21 into the combustion chamber 7 substantially uniformly (FIG. 3). At this time, not only can the insulating chamber 9 filled with the pressurized air be expected to have a heat insulating effect, but since the pressurized air is heated while passing through the chamber 9, the compressed air is further introduced into the combustion chamber 7. Since the fuel is heated by the high temperature endothermic fins 15 when injected, the combustion temperature in the combustion chamber 7 can be increased and the combustion efficiency can be improved.
Further, the pressurized air is injected into the combustion chamber 7 from each of the small holes 21 substantially uniformly, so that oxygen is sufficiently supplied to the inside of the combustion and the inside of the combustion chamber 7 is agitated. Can be improved.

On the other hand, generally, the temperature of the combustion chamber near the surface of the water pipe or the heat absorbing fin is close to the temperature inside the water pipe and becomes higher as the distance from the water pipe increases, but as shown in FIG. By providing the above, the air in the combustion chamber 7 that is very close to the surfaces of the water tubes 14 and the heat absorbing fins 15 where heat is exchanged is stirred, and the water tubes 14 and the heat absorbing fins 15 are
The temperature of the air very close to the surface can be raised to a high temperature, and the heat transfer coefficient can be improved. In addition, since this boiler is directly fired, it can receive radiant heat directly from the flame, so it can improve the heat transfer coefficient as a whole compared to general waste heat boilers, and the overall heat transfer coefficient. Also, high values comparable to oil-fired boilers can be obtained. In addition, the turbulent flow due to the pressurized air prevents impurities such as ash from adhering to the water pipe 14 and the heat absorbing fins 15 and prevents the heat transfer coefficient from decreasing.

The exhaust gas generated by the above combustion is ejector 4
Is guided to the cyclone dust collector 3 via the exhaust pipe 2,
After that, it is discharged from the chimney 5. At this time, the exhaust side is sucked by the ejector 4, so that the downstream side (upper side in the drawing) of the combustion chamber 7 is slightly negative pressure, and the dust inlet 1
Even if 1 is left open, there is no concern that the flame will blow out to the outside. Therefore, dust can be thrown into the combustion chamber 7 at any time even during combustion.

On the other hand, during the above-mentioned combustion, water is supplied from the distribution pipe 16 to each water pipe 14, heat is exchanged, and the steam is used in an external facility through the collecting pipe 18 and the discharge pipe 19. Becomes

In this embodiment, the heat-absorbing fins around the water pipe are provided with a large number of small holes as the pressurized air jet ports.
For example, an arbitrary injection method is adopted, such as forming a separate injection port in the lower part of the combustion chamber, or projecting an extension nozzle or the like into the combustion chamber so that air reaches the inside of the combustion, and injecting pressurized air from the nozzle. Good.

[0019]

As is apparent from the above description, according to the dust-burning boiler of the present invention, the empty chamber serving as a passage for the pressurized air supplied to the combustion chamber is interposed between the combustion chamber and the outside air. Thereby, the combustion chamber is preferably insulated from the outside,
Moreover, the gas passing through the empty space is heated, and the temperature in the combustion chamber is increased synergistically. Further, in order to connect the vacant chamber and the combustion chamber, by injecting pressurized air into the combustion chamber from a large number of small holes provided in the inner wall, oxygen is sufficiently supplied to the combustion interior and the inside of the combustion chamber is evenly distributed. Be stirred. Therefore, normally, the combustion of waste is maintained by supplying about twice the theoretically required amount of air (air excess ratio m = 2), but with this high temperature pressurized air, the air excess ratio m =
It is possible to incinerate dust at about 1.5, the temperature of the flame becomes white at high temperature, and efficient combustion with a high heat quantity is performed in the combustion chamber. Further, by providing the large number of small holes in the heat absorbing fins between the water pipes forming the inner wall, the air in the combustion chamber which is very close to the surfaces of the water pipes and the heat absorbing fins where heat is exchanged is agitated to improve the heat transfer coefficient. And the performance as a boiler is improved. From the above, the effect of the present invention is great.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a schematic configuration of a refuse-fired boiler to which the present invention has been applied.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged view of FIG. 2 illustrating the flow of air in the combustion chamber.

[Explanation of symbols]

 1 Combustion furnace main body 2 Exhaust pipe 3 Dust collector 4 Ejector 5 Chimney 7 Combustion chamber 8 Inner wall 9 Vacancy 10 Outer wall 11 Waste input port 12 Ash removal port 14 Water pipe 15 Endothermic fin 16 Minute pipe 17 Connection pipe 18 Collecting pipe 19 Exhaust pipe 20 Blower 21 Small hole 22 Damper

Claims (3)

[Claims] 1. An inner wall that defines a combustion chamber and in which a large number of water tubes for heat exchange are arranged, an outer wall that surrounds the inner wall, and an inner wall and the outer wall that substantially cover an outer surface of the inner wall. A vacant chamber defined between the vacant chamber, an external pressurized air supply unit connected to the vacant chamber, a pressurized air injection port for injecting pressurized air from the vacant chamber toward the combustion chamber, A dust inlet for injecting dust into the combustion chamber, wherein the pressurized air supplied from the pressurized air supply means is burnt from the pressurized air injection port through the empty space on the outer periphery of the inner wall. A refuse-fired boiler characterized by burning dust in the combustion chamber while injecting it toward the inside of the chamber, and heating the liquid in the water pipe with the combustion heat. 2. The pressurizing air injection port comprises a large number of small holes opened over substantially the entire inner wall so as to connect the vacant chamber and the combustion chamber. Boiler boiler described. 3. The inner wall has a large number of water pipes and heat absorbing fins provided between the water pipes, and the pressurized air injection port has a large number of small holes formed over substantially the entire surface of the heat absorbing fins. The waste-fired boiler according to claim 2, wherein the boiler is a waste-fired boiler.