JPH01254241A - Electric resistance heating type fusion-gasification furnace - Google Patents

Abstract

PURPOSE:To prevent direct contact of a refractory material and heating elements with a harmful gas by arranging heating elements inside an inner shell lined with a refractory material and by forming a gasification chamber further inside, which is separated by a gaspermeable refractory and wherein a crucible is placed. CONSTITUTION:An atmosphere gas 18, which is introduced into a furnace through a gas supply pipe 8, is allowed to flow into a gas room 14 outside a gas-permeable refractory 6 through gas holes 4 penetrating an inner shell 2 and a refractory 7, heated there by heating elements 5 and then further allowed to flow into a gasification chamber 20 as a uniform gas flow through an overall face of the gas-permeable refractory 6 on account of its permeation resistance. At that time, the temperature of the atmosphere gas 16 becomes more uniform as a result of heat exchange with the gas-permeable refractory 6 heated by the heating elements 5. This gas becomes a mixed gas 17 after bringing over a vapor generating from a heated material in a crucible 8 placed in the gasification chamber 20 and is taken out directly through an exhaust pipe 9 opened above the crucible 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the use of metal chloride (?@C
12, CoC12), etc. (hereinafter referred to as the "heated material"), etc. (hereinafter referred to as the "heated material") and other electric resistance heating type melter-gasifiers (hereinafter simply referred to as melter-gasifiers), in particular, with the purpose of significantly extending their lifespan. shall be.

BACKGROUND OF THE INVENTION As shown in FIG. 3, the following problems occur in an IR-built melter-gasifier in which a melter is simply placed inside for heating.

・The object to be heated evaporates and creases in the low-temperature area.

・Since the heating element and refractory material are attacked by the steam of the object to be heated, the heating element and refractory material must be replaced frequently.

°When a large amount of atmospheric gas is introduced, the temperature uniformity of the gas deteriorates, resulting in poor product quality (ultrafine powder, etc.)
do.

The present invention is intended to solve the problems of the conventional method as described above, to provide excellent heat uniformity, and to eliminate damage to the refractory in the furnace, the resistance heating element, and the furnace body due to the deposition of IxJ hot materials. It is something.

As a result of various studies and experiments, the present inventors have succeeded in developing the electrical resistance heating type melter-gasifier of the present invention, and the technical tank bottom of the present invention is specified in each of the claims above. 1 and 2 showing a specific example of the present invention. In this example, the horizontal cross section of the gasifier is circular, and therefore the furnace shell (airtight container), inner shell, and breathable refractory are all cylindrical.
The horizontal cross-sectional shape is not limited.

As shown in FIG. 1, the furnace shell 1 is an airtight container and is provided with an air supply pipe 3 for directly introducing an atmospheric gas 16 such as N2 or air into it. An inner shell 2 is provided inside the furnace shell 1, and the inner shell is lined with a refractory 7, and an atmospheric gas 16'7) vent hole 4 is provided through the inner shell 2 and the lining refractory 7.

An electric resistance heating element 5 (hereinafter simply referred to as a heating element) is installed inside the refractory 7, and a cylindrical refractory 6 with ventilation (hereinafter referred to as an air-permeable refractory) is installed inside the electric resistance heating element 5. A gasification chamber 20 is provided in which a rutz finisher 8 is placed.

A predetermined gap 13 is provided between the furnace shell 1 and the inner shell 2, and serves as a passage for atmospheric gas. Further, the annular space between the inner wall of the inner shell and the breathable refractory forms an atmospheric gas reservoir at the bottom of the tank.

The exhaust pipe 9 of the mixed gas 17 (hereinafter referred to as mixed gas) of the atmospheric gas 16 and the vapor 11 of the object to be heated is: Furnace shell 11 Inner shell 2;
It is installed to penetrate the refractory 7 and the breathable refractory 6, and the mixed gas 17 is directly discharged from the upper part of the crucible 8. In some cases, a vacuum inlet (not shown) may be connected to the exhaust pipe 9 to forcibly suck the mixed gas 17.

Atmospheric gas that entered the furnace from the working air supply pipe 3】6 (solid line arrow)
passes through nine ventilation holes 4 that penetrate through the inner shell and the refractory,
It enters a gas reservoir 14 outside the breathable refractory 6.

Here, the atmospheric gas] 6 is heated by the heating element 5.
Next, when entering the gasification chamber 20 through the breathable refractory 6, the gas flows uniformly from the entire surface of the breathable refractory 6 to the gasification chamber 20 due to the ventilation resistance of the breathable refractory 6. The temperature of the atmospheric gas 16 becomes more uniform due to heat exchange with the air-permeable refractory 6 which is simultaneously heated by the heating element 5.

The atmospheric gas 16 that enters as a uniform gas flow from the breathable refractory 6 envelops the steam 11 of the heated material generated from the crucible 8 and becomes a mixed gas 17, entering the exhaust pipe 9 above the crucible 8. It is directly taken out of the furnace. Therefore, the steam 11 of the heated material generated from Ruth-8 is discharged outside the furnace without coming into contact with anything inside the furnace other than the exhaust gas 1! (manufacturing), so the heating element and refractory will not be attacked by the steam of the heated object. If8 heating is performed using atmospheric gas with uniform temperature]
6 and the radiant heat emitted from the breathable refractory 6, so the heat uniformity is very good. It is more effective to forcefully remove the mixing gas 170 using a vacuum cleaner (not shown).

The above is an example of a tank bottom with a cylindrical gasification chamber; however, similar effects can be achieved in the case of a gasification chamber with a rectangular cross section or rectangular cylindrical shape provided with breathable refractories on both sides. .

The characteristics of the member forming the tank bottom of the present invention are as follows.

+11 Furnace shell 1.12: Airtight container, made of steel that can withstand vacuum to normal pressure.

(2) Inner shell 2: Preferably a heat-resistant metal (SU8).

(3) Refractory 7: 200% higher than the heating temperature of the crucible
The material can withstand temperatures up to 300'C and can withstand high temperature atmospheric gases.

(41 Heating element 5: A material whose maximum operating temperature is 200 to 300'C higher than the heating temperature of the crucible and can withstand high-temperature atmospheric gas.

(5) Breathable refractory 6 °Is the heat resistance temperature the crucible heating temperature? 200~3000C
expensive.

- The ventilation rate is desirably 50-90%, particularly 70-80%.

If the air permeability is lower than 50 yen, the gas flow will be uniform, but the pressure loss will be large and only a small amount of atmosphere will flow.

If the permeability is higher than 904, a large amount of atmospheric gas can flow because the pressure loss is small, but the uniformity of the gas flow deteriorates and the physical strength decreases.The thickness of the permeable refractory is 10.
The diameter is preferably about 50 m, particularly preferably 5 to 10 times the average diameter of the pores.

The height is 400 cm and the diameter is about 250 mm, and is a cylinder or square tube, but the size is not limited.

If it is thinner than low, the pressure loss is small and a large amount of atmospheric gas can flow, but heat is easily transferred inside from the resistance heating element, whereas the 1irf gas flow and gas temperature uniformity are lost. Physical strength is also low.

If it is thicker than 50 mm, the pressure loss is large and only a small amount of atmospheric gas can flow, and heat is less likely to be transferred inside from the resistance heating element, but the gas flow and gas temperature are more uniform. Physical strength is also high: the average diameter of pores in breathable refractories is 2 m~
4m is desirable.

If it is smaller than 2 fins, there will be a pressure drop and the uniformity of heat and gas flow will be good, but the blinds will be large.

If it is larger than 41I11, the pressure drop will be small and the uniformity of heat uniformity and gas flow will be poor, but clogging will be small.

(6) Ruth〆8, Mixed gas exhaust pipe 9 - A material with heat resistance higher than the boiling point temperature of the object to be heated (hereinafter referred to as heating temperature) by IOO'C or more.

° Materials that are not attacked by gas mixtures at heating temperatures.

- A material that is not corroded by the object to be heated, such as well-known ceramics such as cardan and alumina, or metals such as pure nickel, can be used. As shown in FIG. 2, the shape of the end of the exhaust pipe inside the furnace may be a rat-I shape, a funnel shape, a reduced diameter tube shape, or a bell shape so that the mixed gas can be easily absorbed.

Effects of the Invention Since the steam of the object to be heated does not come into direct contact with the furnace body, refractories, or heating elements, the degree of freedom in selecting the material is greatly increased. Specifically, it becomes possible to use a ceramic fiber molded body with high heat insulation properties and a heating element such as inexpensive nichrome wire, improving the thermal efficiency of the entire furnace.

This furnace is not only a melter-gasifier that simply melts metal chlorides, but also an effective furnace for heating materials such as zinc, which emit gas harmful to refractories and heating elements during melting or heating. .

■ Since the refractories and heating elements of the melter-gasifier do not come into contact with harmful gases, there is no damage caused by this, and the lifespan is approximately four times longer (
3 months → 1 year) extended.

■ Uniform heating by convection of uniformly heated atmospheric gas and radiation heating via breathable refractories.

■ Since the material of the refractory can be freely selected without considering the influence of evaporable substances, it is possible to use refractories with high heat insulation properties and use them in a continuous furnace.
Highly insulating refractories and atmospheric gas flow reduce the amount of heat dissipated and improve thermal efficiency.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view showing the inner end shape of an exhaust pipe used in the present invention, and Fig. 3 is a conventional embodiment. FIG. The numbers in the figure are as follows. 1: Airtight container (furnace shell), 2: Inner shell, 3: Atmospheric gas supply pipe, 4: Ventilation hole, 5: Heating element, 6: Breathable refractory, 7: Refractory, 8 Nil hook, Exhaust pipe, ] O
: Heated object, 11: Heated object steam, 12: Airtight container (lid), 13: Gap between furnace shell and inner shell, 14:
Atmospheric gas reservoir, 15: Inner lid, 16: Atmospheric gas,
17: Mixed gas, 20: Gasification chamber. Figure 1 Figure 2 Figure 3 σ 107/

Claims (1)

[Scope of Claims] 1. An inner shell lined with a refractory material and provided with an atmospheric gas vent is placed in an airtight container provided with an atmospheric gas supply pipe, with a required gap therebetween; A breathable refractory is installed inside to provide an atmospheric gas reservoir between the inner wall of the inner shell and the breathable refractory, and an electric resistance heating element is installed in the gas reservoir, which is partitioned by the breathable refractory. An electric resistance heating type melter-gasifier, characterized in that an inner end opening of a mixed gas exhaust pipe is arranged above a gasification chamber. 2. The electric resistance heating type melter-gasifier according to claim 1, wherein the shape of the inner end of the exhaust pipe is a trumpet shape, a funnel shape, a tube shape with different diameters, a bell shape, or a straight tube shape. .