JP3365584B2 - Ash melting method and equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ash melting method and apparatus.

[0002]

2. Description of the Related Art A conventional combustion-type ash melting furnace is a surface melting furnace that melts from the surface of a layer of ash by a burner flame and radiant heating of the inner wall of the furnace, and the total amount of ash is mixed with combustion air or this flow to produce flame There are two major types, such as swirl melting furnaces, which melt by adhering to the inside and inside walls of the furnace.

[0003]

In the surface melting furnace described above, the ash melts only on its surface, and the ash layer immediately below serves as a heat insulating layer to protect the surrounding or lower furnace body structure from heat and erosion. Since only the surface of the ash layer is melted by radiant heating in the furnace, a large load cannot be taken, resulting in a large size and low efficiency. Generally, there are problems such as high flame temperature and high NOx. Further, since the swirling melting furnace described above is a method of directly hitting the flame and ash particles in the middle of melting on the inner wall of the furnace, the damage in the furnace is severe. In this type of melting furnace, the course of combustion gas and ash flow is likely to be fixed, and the furnace inner wall of this course requires frequent maintenance. In this method of mixing all the amount of ash into the flame or combustion gas, it is necessary to mix a large amount of ash into the flame in order to improve the heat source unit, but at this time it is difficult to maintain the flame and control combustion, and unburned There are problems such as the generation of minutes.

[0004]

In order to solve the above-mentioned problems, the present invention burns a part of ash to be melted together with a combustion-supporting agent such as fuel and air in an ash-melting burner to form a molten particle together with a flame in a furnace. is ejected at high speed into the ash in to be melted was charged within, it is provided a ash melting method characterized by facilitating the melting of ash deep ash by transferring heat in the furnace of the furnace is there.

The present invention also relates to the ash to be melted in the furnace.
The inclined melting section is constructed below the main ash supply section where
Installed ash melting burner on the furnace wall facing the inclined melting part of
Then, burn part of the ash to be melted to the ash melting burner side.
Installed a premixed ash supply unit that mixes with fuel, air, and other combustion-supporting agents.
Fusing the premixed ash with fuel, air and other combustion-supporting agents
Burned by a burner to form molten particles together with the flame, the furnace
With a configuration that ejects at high speed into the ash that is to be melted and is to be melted
The present invention provides an ash melting device characterized by
It

[0006]

Function: A portion of the ash to be melted from the ash melting burner is jetted at high speed as molten particles into the ash to be melted introduced into the furnace together with the flame. The ash blown out at high speed with the flame
The molten particles of premixed ash (including those that have been melted and those that are in the process of being melted ) from the side of the melting burner are excellent in straightness, and the heat and kinetic energy possessed by them make it a combustion jet and the furnace effectively
It strikes the surface of the ash layer inside and transfers heat to deep parts to promote melting. Molten particles melt particles entering into the ash layer around the furnace <br/> ash remaining the trigger (nucleus), and also the surface to initiate melting of the furnace, the still powdery furnace ash surface Prevent the scattering of ash. Furthermore, the surface of the furnace ash layer, joined by radiant heat from the flame and furnace, melting accelerated by the effect
To be done . The mixing ratio of the premixed ash from the ash melting burner side varies depending on the material of the ash, the property of the fuel, and the structure of the furnace body. Generally, for low-calorie fuels and non-flammable fuels, the ash premixing ratio is suppressed to 50% or less because of flame stability.

[0007]

EXAMPLES Reference numeral 1 is a furnace body , and 2 is a main ash supply section . Reference numeral 3 denotes an inclined melting section provided below the main ash supply section 2 . An ash melting burner 4 is installed on the opposite wall of the inclined melting section 3, and the ash melting burner 4 is provided with a fuel supply section 5, a combustion-supporting agent supply section 6 such as air, and a premixed ash supply section 7. A complete melting portion 12 is formed below the portion 3. 8 is a pusher, and 9 is a discharge part. In some cases, the premix
A part of the ash to be melted may be mixed into the fuel or a part of the ash to be melted may be mixed into the combustion supporting agent without providing the combined ash supply unit 7.

While the ash 10 is charged from the main ash supply unit 2,
The ash to be melted from the premixed ash supply unit 7 is supplied to the ash melting burner 4.
Part, also from the fuel supply unit 5 and the combustion-supporting agent supply unit 6, respectively, the fuel gas and air or the like is introduced into the ash melting burner 4, the start of the combustion at the burner 4, wherein
The premixed ash supplied from the premixed ash supply unit 7 becomes molten particles and is jetted at high speed into the ash 10 in the furnace body 1 together with the flame 11. The molten particles of the premixed ash blown out at high speed (including those that have been melted and those that are in the process of being melted ) have excellent straightness, and due to the heat and kinetic energy that they possess, they become a combustion jet.
Effectively beating the ash 10 layer surface, transferring heat to the deep I,
Promotes melting. The molten particles that have entered the ash 10 layer serve as a trigger (nucleus) for the surrounding ash 10 to start melting, and the molten particles that remain on the surface prevent the ash from scattering from the surface of the ash 10 which is still powdery. Further, the surface of the ash 10 layer is heated by the flame 11 and radiant heating from the inside of the furnace, and the melting is promoted by the above effect. It is supplied from the premixed ash supply unit 7.
The mixing ratio of the premixed ash depends on the material of the ash, the properties of the fuel, the furnace body 1
It depends on the structure. Generally, in the case of low-calorie fuel, etc., the premixing ratio of ash is suppressed to 50% or less for stability of flame.

In general, when the materials are mixed in the flame, the flame temperature is lowered by the heat absorption, so that the burner itself may be a general-purpose one without the NOx reduction measures. However, more N
A low NOx burner can be used to seek Ox reduction. In this case, a low NOx burner that blows out at high speed is required to maintain the momentum of the flame containing ash particles, but these are generally unsuitable for this system because the flow velocity is slow. The burner effective for this method is "direct injection in the fuel furnace".
Since the NOx reduction effect is obtained as the flow velocity is increased, the kinetic energy, which is a feature of the present invention, can be maintained at that time. Fig. 2 shows an example of a burner structure for an ash melting furnace.
Shown in. The principle of NOx reduction is mainly to lower the flame temperature. However, when it is desired to melt the material in a short flame within a limited space, the flame temperature must be raised to the contrary. It goes without saying that the optimum flame state must be selected depending on how to set the ratio of complete melting in the flame and how to set the premixing ratio. In some cases, oxygen may be used as a combustion support agent.

[0010]

As described above, the present invention has the following effects. Flame temperature drops from tens to hundreds of degrees, N
Generation of Ox is suppressed. The premixed ash is effectively melted in a flame having a high heat transfer effect. This impact heating also promotes melting at the surface portion, and together with this, highly efficient melting is realized. Since the flame containing particles is excellent in straightness, a heat spot on the surface of the ash layer, which is required when the surface is melted, is easily formed. (Generally, in the case of surface melting, it is better to have a high temperature part that actively starts melting.) The function of protecting the furnace body by the lower unmelted ash layer, which is a feature of conventional surface melting furnaces, can be maintained. . Since the overall heat transfer effect is high, it is possible to increase the load per unit volume, and it is possible to achieve more efficient melting and downsizing of the device .

[0011]

[Brief description of drawings]

FIG. 1 is an overall cross-sectional explanatory view.

FIG. 2 is an explanatory view of an ash melting burner.

[Explanation of symbols]

1 Furnace Body 2 Main Ash Supply Section 3 Gradient Melting Section 4 Ash Melting Burner 5 Fuel Supply Section 6 Combustion Agent Supply Section 7 Premixed Ash Supply Section 8 Pusher 9 Discharge Section 10 Ash 11 Flame

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) F23G 5/00 115 F27B 3/20 F23J 1/00

Claims (2)

(57) [Claims] 1. A part of the ash to be melted is burned by an ash melting burner together with a combustion-supporting agent such as fuel and air to be ejected at high speed into the ash to be melted, together with a flame as molten particles, A method for melting ash, characterized in that heat is transferred to a deep portion of the ash in the furnace to accelerate melting of the ash in the furnace . 2. A main for charging ash to be melted in a furnace
An inclined melting section is formed below the ash supply section.
Install an ash melting burner on the wall of the furnace facing the
A part of the ash to be melted is burnt to the burner side, such as fuel and air.
A premixed ash supply unit that mixes with the agent is provided to burn the premixed ash.
Combustion with the ash-melting burner together with fuel and air
Melted into the furnace together with the flame as molten particles
An ash melting device characterized in that the ash is ejected at high speed into ash to be discharged .