JPH0331966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention forms a high-temperature hearth of carbon-based combustible materials in a furnace, and collects fine industrial waste and its intermediate products.
A method for melting industrial waste, in which the high-temperature hearth is blown onto the high-temperature hearth through the tuyere 4 by a combustion oxygen-containing gas to be melted, and the molten material is taken out of the furnace from the lower part of the high-temperature hearth. Regarding.

The above method was previously proposed in Japanese Patent Application Laid-Open No. 56-144321, and is designed to melt fine industrial waste and its intermediate products in a good manner while preventing troubles caused by dust scattering. It was devised. However, if the fine industrial waste or its intermediate treatment products are incombustible or mainly non-combustible, such as recovered dust from waste incineration ash or melting furnaces, especially when supplied in large quantities, high-temperature furnaces It became extremely difficult or impossible to stably maintain the bed at the high temperatures necessary for melting the waste, and further improvements were needed.

The purpose of the present invention is to maintain a high-temperature hearth at a sufficiently high temperature so that good and stable melting of a large amount of waste can be continued even if fine industrial waste or its intermediate processed products are nonflammable. The point is to make it.

The characteristic means of the industrial waste melting method according to the present invention is to supply fuel into the furnace from the periphery of the high-temperature hearth so as to form a combustion zone in the high-temperature hearth or in the vicinity of the tuyere. Its functions and effects are as follows.

In other words, when we investigated the reason why the high-temperature hearth could not be stably maintained at a sufficiently high temperature when non-flammable fine industrial waste was blown onto the high-temperature hearth through the tuyeres, we found that carbon The melt adhering to the combustible material cuts off the supply of oxygen-containing gas from the tuyere, and the carbon-based combustible material coated with the melt becomes unable to continue burning, causing its temperature to drop.
It has been found that this is because the viscosity of the melt increases as the temperature decreases and it no longer flows down, further accelerating the temperature decrease.

Therefore, in order to prevent the temperature of the melt from decreasing when the supply of oxygen-containing gas to the carbon-based combustible material is cut off by the melt, it is necessary to When fuel was supplied from the periphery of the high-temperature furnace into the furnace to form a combustion zone nearby, and the heat generated by the fuel was used to heat the molten material, fine industrial particles supplied from the tuyere The waste rapidly melts and flows down, making it possible to stably supply oxygen-containing gas to the carbon-based combustible materials near the tuyere, making it easier to maintain the high-temperature hearth at a sufficiently high temperature. Furthermore, even if the supply of oxygen-containing gas to the carbon-based combustible material is temporarily cut off by the melt coating, it is possible to reliably prevent the increase in viscosity due to the temperature drop of the melt.
The molten material flows down in a short time, and oxygen-containing gas can be supplied to the carbon-based combustible materials again, making it possible to reliably prevent the temperature of the high-temperature hearth from dropping dramatically.

As a result, it has become possible to reliably melt fine industrial waste and its intermediate processed materials, even if all or most of them are non-flammable, while supplying twice as much as before, and melting process The scope of application to objects has expanded, making it even more practical.
It has become possible to perform good melting treatment of industrial waste.

Next, examples will be shown using figures.

Lump or granular coke and industrial waste are supplied from the hopper 2 into the vertical furnace 3 by opening and closing the double dampers 1a and 1b alternately or simultaneously, and the coke layer filled in the lower part of the furnace is Tuyere 4
The waste 6 is heated and melted in the upper part of the high-temperature hearth 5, and the molten material flows down the gap in the high-temperature hearth 5 to form a high-temperature hearth 5. The molten material is taken out of the furnace from the lower part of the bed 5 through a discharge passage 7, and the molten material is air-cooled and molded into a lump by an air-cooled slag manufacturing device 27.

Most of the combustion exhaust gas rising from the high-temperature hearth 5 is transferred from an exhaust gas path 8 connected to the upper part of the furnace to an air preheater 11, an exhaust heat boiler 9, a dust removal cyclone 10,
It is sent to the desulfurization device 12, the wet dust removal device 13, and the exhaust blower 14 in that order and released into the atmosphere, and
A part of the combustion exhaust gas is passed through the exhaust passage 7 to keep the molten material warm.
released into the atmosphere. The air preheater 11 preheats the combustion air supplied from the blower 15 to the primary tuyere 4 to maintain the temperature of the high-temperature hearth 5 at a high enough temperature for melting industrial waste, and Based on the information from the furnace pressure detector 29, the controller 30
Then, the damper 16 is automatically operated to adjust the furnace internal pressure, and the ratio of combustion exhaust gas supplied to the exhaust gas path 8 and the exhaust path 7 is appropriately set.

Combustible gas combustion air is supplied to the blower 15 above the high temperature hearth 5 from the secondary tuyere 17 and the tertiary tuyere 18 connected in parallel with the primary tuyere 4 to the upper and lower parts of the furnace 3, Based on the information from the flowmeter 19a, the controller 20a automatically operates the flow control valve 21a to maintain the amount of combustion air supplied from the primary tuyere 4 to the high-temperature hearth 5 almost constant, and similarly, Flow meter 19b, controller 20b, flow control valve 2
1b maintains the air supply amount for combustible gas combustion from the tertiary tuyere 18 almost constant, and the flowmeter 1
9c and the meter 22 that detects the oxygen gas concentration of the combustion exhaust gas on the downstream side of the wet dust removal device 13, the controller 20c controls the flow control valve 2.
1c is automatically operated to adjust the amount of air supplied from the secondary tuyere 17 for combustible gas combustion so as to maintain the oxygen gas concentration of the combustion exhaust gas within the set range, thereby reducing the overall amount of air supplied. To ensure that there is no excess or shortage of coke, that coke consumption is not greater than necessary, and that sufficient combustion takes place in the furnace.

The dust collected by the exhaust heat boiler 9 and the cyclone 10 is transported to the hopper 23 where fine industrial waste is stored, and the fine fuel such as coke powder and coal powder from the hopper 24 and the fine industrial waste from the hopper 23 are transported. The mixture with waste is continuously or intermittently supplied in appropriate amounts to the air supply path 26 from the hopper 25 to the primary tuyere 4, and the fine industrial waste is blown from the primary tuyere 4 to the high-temperature hearth 5. At the same time, the pulverized fuel is burned around the high temperature hearth 4 near the primary tuyere 4 to promote melting and melt flow.

The industrial wastes supplied from the hopper 2 and the primary tuyeres 4 are, for example, various types of waste such as unwatered sludge, municipal waste incineration ash, tire scraps, and waste catalysts, or intermediate products thereof.

Next, another example will be shown.

In addition to coke, appropriate carbon combustible materials such as briquettes such as anthracite and graphite electrode scraps can be used to form the high-temperature hearth.

Oxygen-enriched air or the like may be supplied to the tuyere 4 that blows fine industrial waste onto the high-temperature hearth 5.
These gases are collectively referred to as combustion oxygen-containing gas.

Instead of the pulverized fuel, fuel gas or oil may be supplied, or fuel may be supplied into the furnace near the tuyeres 4. However, if the high-temperature hearth 5 is made of coke and coke powder is used, one type of fuel can be used, and there are advantages such as being able to easily obtain a high temperature.
It is best to keep the ratio of 0.1 mm or less to 90% or more, and the ratio of 0.1 mm or less to 10% or less, and 2 per 41 tuyeres.
It is recommended to supply coke powder at a rate of approximately 1 kg/h.

[Brief explanation of the drawing]

The drawing is a flow sheet of the apparatus used in the method of the present invention. 3... Furnace, 4... Tuyere, 5... High temperature hearth.

Claims (1)

[Claims] 1. A high-temperature hearth 5 of carbon-based combustible material is formed in the furnace 3, and fine industrial waste and its intermediate products are fed to the high-temperature hearth 5 into oxygen-containing gas for combustion supplied thereto. Therefore, it is a method of blowing from the tuyere 4 to melt the material and taking out the molten material from the lower part of the high temperature hearth 5 to the outside of the furnace, and in the high temperature hearth 5, and
A method for melting industrial waste, in which fuel is supplied into the furnace 3 from the periphery of the high-temperature hearth 5 so as to form a combustion zone at or near the tuyere 4.