JPH0160728B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to prevent heavy metals from flowing out when various industrial wastes such as sewage sludge, or intermediately processed products obtained by drying, incinerating or pulverizing them as necessary, are used in landfills. Regarding furnaces that incinerate or melt industrial waste or its intermediate products to prevent it from burning or to make it available for use as construction aggregate, the upper part of a high-temperature hearth made of carbon-based combustible materials is used. The present invention relates to an industrial waste melting furnace configured to incinerate and melt the waste in a furnace and take out the molten material from the lower side of the high-temperature hearth.

In the upper melting furnace, if the oxygen concentration of the combustion air supplied to the high-temperature hearth is increased, the amount of combustion air supplied can be reduced compared to the case where air is simply supplied, and carbon-based combustible substances, e.g. The temperature of the high-temperature hearth can be maintained at the high temperature required for removing the melt, e.g. 1400°C or higher, while reducing the amount of coke consumed. By lowering the column speed, guest scattering and associated clinker generation can be suppressed, and in addition, a large amount of thermal energy is suppressed from being emitted along with the exhaust gas, and from an economical point of view, the consumption of carbon-based combustible substances is reduced. The furnace can be operated under advantageous conditions, and its heat dissipation is better than that of large furnaces, making it difficult to maintain the temperature of the high-temperature hearth at the desired temperature when just air is used as combustion air. Even in a small furnace with an inner diameter of 700 mm or less, which would be difficult, extremely effective advantages such as the ability to operate the furnace as desired can be obtained. but,
Conventionally, to enrich the combustion air with oxygen, a method of supplying oxygen from an oxygen cylinder or vaporized oxygen from a liquid oxygen tank to the air has been adopted, but in this case, expensive oxygen is required. economic disadvantages, the dangers associated with using oxygen cylinders or liquid oxygen tanks in high-temperature areas near the furnace, and the need for special workers and storage facilities suitable for handling oxygen under the High Pressure Gas Control Law. There were some inconveniences, such as having to do it.

The purpose of the present invention is to improve a means for increasing the oxygen concentration of combustion air to one that is superior in terms of economy, safety, and operability, and to improve thermal efficiency as well as to reduce the size of oxygen enrichment equipment. The aim is to improve the equipment cost and operating cost to be cheaper.

Embodiments of the present invention will be described in detail below based on illustrative drawings.

As shown in FIG. 1, a high-temperature hearth 2 made of carbon-based combustible material is formed in a cupola type melting furnace 1, and a damper 4 is connected to the high-temperature hearth 2 from a hopper 3.
a and 4b are alternately opened and closed to supply the waste or its intermediate treated material in a mixed state with the carbon-based combustible material or alternately, and to fill the packed bed 5 with the carbon-based combustible material and the waste or its intermediate treated material. The combustion air is supplied to the high-temperature hearth 2 from the lower first tuyere 6 to burn and melt the waste or its intermediate products in the upper part of the high-temperature hearth 2. Then, the combustion exhaust gas is discharged to an ascending passage 7 formed above the high temperature hearth 2 and a lower passage 8 connected to the lower part of the high temperature hearth 2, and,
Taking the melt out of the furnace through the lower flow path 8,
Then, the combustion exhaust gas generated from the high temperature hearth 2 is
In order to burn and decompose the odor components and harmful components generated when passing through the packed bed 5, the combustion air supplied from the second tuyere 9 is used to perform post-combustion in the ascending flow path 7. Furthermore, high temperature hearth 2
The water cooling jacket 10 is constructed by forming the side walls of the portions into a double pipe structure.

As shown in FIG. 2, the combustion exhaust gas from the upward passage 7 is transferred to a boiler 11, a heat exchanger 12, and
The gas is discharged into the atmosphere through an exhaust gas treatment device 13 equipped with a dust collector, a deodorizer, and the like. or,
The combustion air supply path 15 to the high temperature hearth 2, which is connected to the first tuyere 6 and is equipped with a blower 14 whose air volume can be adjusted, has two locations, an upstream portion and a downstream portion, for heat exchange. Provided in a state located within the container 12,
In the combustion air supply path 15 between the upstream part and the downstream part located in the heat exchanger 12,
An oxygen enrichment device 16 equipped with an oxygen preferentially permeable membrane made of a polymeric material such as polydimethylsiloxane, polyvinyl chloride, or polypropylene is provided;
The oxygen enrichment device 16 is configured to increase the oxygen concentration of the combustion air to 23% to 30%. In addition, the heat exchanger 12 is heated by combustion exhaust gas to heat the air to 60 to 80 degrees Celsius, and then heated to 400 degrees Celsius.
The oxygen enrichment device 16 is formed so that it can be heated to ℃.
The permeation rate in the enrichment device 16 is increased by preheating the air supplied to the enrichment device 16 to 60° C. to 80° C., and the air that has passed through the enrichment device 16 is passed through the heat exchanger 12 again.
It is heated to 400℃.

In more detail, the oxygen concentration of the combustion air is 23
% to 30%, by setting the amount of combustion air supplied to the high-temperature hearth 2 to 0.95 to 1.1 times the theoretical amount of air for combustion of the carbon-based combustible material supplied to the high-temperature hearth 2. Therefore, the temperature of the high-temperature hearth 2 can be maintained at 1400° C. or higher, which is necessary for taking out the melt. As a result, the rising gas superficial velocity was reduced to 20Nm ³ / when air was simply supplied as combustion air.
^m2・min or more, and the consumption rate of carbon-based combustible substances is 100 to 120Kg/m2・h, which is lower than the ^1500Kg / ^m2・h or more when simply using air as combustion air. In addition, it is possible to suppress dust scattering and the clinker generation associated with it, and also to suppress the emission of a large amount of thermal energy with exhaust gas, and to reduce the consumption of carbon-based combustible substances. The furnace can be operated under advantageous conditions in terms of the combustion air, and in addition, it is difficult to maintain the temperature of the high-temperature hearth 2 at the desired temperature when using simple air as the combustion air.
Even a small 600mm furnace can be operated as desired.

Further, a supply path 17 to the second tuyere 9 is connected to the air supply path 15, and a valve 18 for changing and adjusting the opening amount of the supply path 17 is provided. It is possible to supply the desired amount of combustion air. In addition, the air supply amount from the second tuyere 9 is:
It is preferable to set the difference between 1.0 to 1.2 times the theoretical combustion air amount of the carbon-based combustible material and industrial waste to be replenished and the amount supplied from the primary tuyere 6.

In addition to sewage sludge, the above-mentioned melting furnace can be used to process various industrial wastes such as tire scraps, municipal waste incineration ash, and waste catalysts, as well as intermediate products thereof.
can.

In addition, the specific configuration of the melting furnace is as follows:
Various modifications can be made, such as a furnace without a furnace, and the present invention is applicable to furnaces of various specifications, such as large and small furnaces.

Further, as the carbon-based combustible material forming the high-temperature hearth 1, it is preferable to mainly use coke, but various materials such as briquettes such as anthracite, black smoke electrode scraps, etc. may also be used.

Furthermore, the present invention may be practiced without providing a device for heating combustion air.

Further, in order to increase the oxygen concentration of the combustion air, it is preferable to set it to 23% to 30% as described in the embodiment, but it may be set to other concentrations.

In summary, the characteristic configuration of the present invention is that the high temperature hearth 2
In the heat exchanger 12 that preheats the combustion air to be heated by the combustion exhaust gas from the high-temperature hearth 2, two locations, an upstream portion and a downstream portion, of the combustion air supply path 15 are arranged. An oxygen enrichment device 16 equipped with an oxygen preferential permeation membrane is provided in the combustion air supply path 15 between the combustion air supply path 15 and the downstream portion, and the air supplied to the oxygen enrichment device 16 is heated to 60 to 80°C. The heat exchanger 12 is formed in this manner, and its functions and effects are as follows.

That is, since the oxygen enrichment device 16 equipped with an oxygen preferential permeation membrane is used to increase the oxygen concentration of the combustion air supplied to the high-temperature hearth 2, an oxygen cylinder or a liquid oxygen tank is used to increase the oxygen concentration of the combustion air. Compared to the above-mentioned conventional means of increasing the oxygen concentration in the air, it is economically advantageous because it does not use expensive oxygen, and it is safe because it does not use oxygen cylinders that have a risk of explosion. The desired purpose can be achieved with good operability without the need for special workers who are suitable for handling oxygen enrichment devices such as when using cylinders, or permission based on the law. As a result, an industrial waste melting furnace that can be used more conveniently has been obtained.

Furthermore, not only can thermal efficiency be improved by preheating the combustion air using the combustion exhaust gas in the heat exchanger 12, but also the air supplied to the oxygen enrichment device 16 can be
By preheating to 80°C, the membrane permeation rate can be greatly increased compared to oxygen enriching air at room temperature, thereby reducing the size and cost of the oxygen enrichment device 16 and reducing combustion air. By lowering the pressure of the blower in the supply path 15, it is possible to sufficiently reduce costs and operating expenses, and it has become possible to provide equipment that is extremely advantageous in terms of economy.

In addition, in the oxygen enrichment device 16, the oxygen concentration of the oxygen-enriched air and the flow rate of air permeating through the membrane change as the air temperature changes, for example, as shown in FIG. It can be seen that the permeation flow rate can be greatly increased compared to air at room temperature (approximately 25°C) while maintaining the oxygen concentration of 23% or more, which is the lower limit of general oxygen-enriched air.

[Brief explanation of drawings]

The drawings illustrate embodiments of the industrial waste melting furnace according to the present invention, and FIG. 1 is a cutaway front view of the melting furnace;
FIG. 2 is a block diagram showing the combustion air supply structure. FIG. 3 is a graph showing the characteristics of the oxygen enrichment device. 2... High temperature hearth, 12... Heat exchanger, 15...
Combustion air supply path, 16...Oxygen enrichment device.

Claims (1)

[Claims] 1. An industrial waste melting furnace configured to incinerate and melt industrial waste or its intermediate products in the upper part of a high-temperature hearth 2 made of carbon-based combustible material, and take out the molten material from the lower side of the high-temperature hearth 2. a heat exchanger 12 that preheats combustion air to the high-temperature hearth 2 with combustion exhaust gas from the high-temperature hearth 2;
Two locations, an upstream portion and a downstream portion, of the combustion air supply path 15 are arranged within the combustion air supply path 15, and the combustion air supply path 15 is disposed between the upstream portion and the downstream portion.
An oxygen enrichment device 16 equipped with an oxygen preferentially permeable membrane is provided, and the air supplied to the oxygen enrichment device 16 is
An industrial waste melting furnace in which the heat exchanger 12 is formed to have a temperature of 60 to 80°C.