JP2000161868A - Method for evaluating damage on refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability of a melting furnace for thermally decomposing, melting and solidifying refuse by detecting damage of an apparatus composed of refractories based on the state change of a medium before and after passing through the refractories thereby facilitating evaluation of damage on the apparatus in the furnace and prediction of service life. SOLUTION: When refuse is melted and solidified, combustion gas and char produced from a thermal decomposition unit under high temperature are fed, along with air, through an inlet 1 to a melting furnace body 2 where they are heated to produce molten slag. Damage on refractories employed in the apparatus is detected by coating the surface of a buried substance with a substance exhibiting a damage rate different from that of the refractories. Variation in the physical properties of the buried substance is determined by measuring state change of a medium before and after passing through the buried terminal, e.g. increase of resistance due to abrasion of graphite, breakage of a metal lead or variation of current velocity or temperature in a metal tube circulating a gas, attributed to melting or abrasion of the coating material of the buried terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasification and melting furnace for melting and solidifying waste, which measures the amount of damage caused by the molten slag of the refractory constituting the furnace body and the change in physical properties of the substance embedded in the refractory. The present invention relates to a technique for evaluating a damage amount of a furnace device made of a refractory in an actual use environment by detecting the damage, and for providing a damage amount evaluation method for estimating a life.

[0002]

2. Description of the Related Art Conventionally, general waste and industrial waste discharged from households are collected and then incinerated in an incinerator. However, it is desired from the viewpoint of environmental protection to secure a landfill for incinerated ash generated by incineration and to prevent harmful substances such as dioxin from being dispersed. After pyrolysis of general waste, the gasification and melting furnace, which self-combustes with the generated gas and char and melts and solidifies the waste, satisfies the above requirements and also as a future waste melting system from the viewpoint of energy saving. Attracting attention.

FIG. 1 shows the structure and function of a gasification and melting furnace.
The combustion gas and char generated by the pyrolysis device at a high temperature are supplied to the melting furnace main body 2 via the char and the air inlet 1 together with air. The supplied char mixes the combustion gas and air and is heated at about 1400 ° C. to become molten slag. The molten slag passes through the furnace wall 3 and the slag tap 4, falls into the slag cooling water tank, and solidified slag is carried out from the slag outlet 6. On the other hand, the gas after combustion forms a swirling flow,
It is discharged from the discharge port 7.

[0004] Fixed bricks and irregular refractories (castable)
The method for evaluating the amount of damage to in-furnace equipment, which is constituted by the above, is limited to visual inspection after operation of the facility. It is not applicable in a heat-resistant environment, such as mounting a sensor on a refractory or adding a measuring device by a method of placing a material to be measured near the actual machine and evaluating the damage by ultrasonic waves (literature; non-destructive evaluation technology for ceramics). is there. In addition, in the method of estimating the life of the equipment by installing the material to be measured near the actual equipment and evaluating the amount of damage to the material to be measured, the amount of damage to the actual equipment itself is not directly evaluated, Cannot be evaluated.

[0005]

The in-furnace equipment made of a refractory has a high temperature gas generated during the combustion of the char and a high temperature gas.
It is in a severe corrosive environment exposed to molten slag at 400 to 1500 ° C. Particularly, the molten slag at a high temperature causes the refractory to be eroded, penetrates into the refractory, forms a deteriorated layer by a chemical reaction, and causes material damage such as structural spalling due to temperature fluctuation.

[0006] Therefore, an object of the present invention is to provide a method for evaluating the amount of damage to a refractory in which the reliability of a melting furnace is improved by evaluating the amount of damage to in-furnace equipment constituted by the refractory and estimating the life. To provide.

[0007]

According to the present invention, there is provided a refractory comprising:
The purpose of the present invention is to measure the physical properties of terminals buried in dimensions or more, evaluate the damage in stages, determine the life of the furnace equipment in the actual environment, determine maintenance and replace parts.

[0008] The embedded sensing material is graphite which is oxidized and worn by contact with oxygen, and which transmits electric signals.
Metallic wires such as W, Pt, and Mo having a melting point of 400 ° C. or more, and heat-resistant metal hollow tubes having a melting point of 1400 ° C. or more in which gas is circulated can be applied. It is composed of elements that can predict the deterioration before the refractory itself is damaged by coating the refractory with the different refractory from the constituent refractory. A furnace wall structure using a typical buried terminal is shown in FIGS.

The change in the physical property value of the buried substance constituting the damage evaluation terminal according to the present invention is caused by an increase in the resistance value due to a decrease in the abrasion of graphite caused by the erosion or abrasion of the coating material of the buried terminal, and a metallic conductor. The damage to the furnace equipment is evaluated by measuring changes in the state before and after the passage of the medium moving inside the buried substance, such as disconnection of the pipe, flow velocity in the metal pipe in which the gas is circulated, and temperature changes.

Generally, refractories are porous, so that they are in a high-temperature corrosive gas environment of 1000 ° C. or higher inside the actual machine members, and graphite and metals as buried substances are deteriorated by corrosion and oxidation. In a combination of a refractory used for a member of an actual machine and a covering material of a buried substance embedded in the refractory, heat-resistant Al ₂ O ₃ , SiO ₂ , Cr ₂ O ₃ ,
In addition to oxides such as ZrO ₂ , nitrides such as Si ₃ N ₄ and TiN, aggregates such as C and SiC, and low-porosity refractories made of particles are effective.

It is desired that the coating material of the buried substance has a higher erosion rate for slag than a erosion rate for refractories constituting furnace equipment. This is because it is necessary to detect in advance the significant penetration of slag into the refractory.

[0012]

[Table 1]

[0013] The erosion and permeability of the main refractories were evaluated by a rotating cylindrical immersion test. The sample is 15mmφ × 60mm
Was used. The composition of the slag used was 35
wt% SiO ₂ -30 wt% CaO-5 wt% MgO-2
_{wt% Na 2 O-2wt%} TiO 2, test temperature 140
0 ° C., immersion time is 1 to 10 hours, rotation number of test piece is 30
It was set to 0 rpm. Table 1 shows the test results. Erosion rate (a), faster in the order of (b), (c), (d), (e), Cr 2
In the O ₃ -based (c) and (d), slag easily penetrates. Therefore, as a combination of a refractory and a covering material, it is appropriate that the furnace wall and the slag tap are composed of the refractory materials (c) to (d) and (a) and (b) are used as the covering material of the embedded terminal. It is.

In the case of refractories in which slag is remarkably infiltrated as shown in (c) and (d), the erosion rate of the slag is determined by combining the refractory and the coating material, which have been experimentally determined in advance, so that the slag can be incorporated into the refractory. The penetration depth of the slag and the amount of erosion of the refractory can be evaluated.

The arrangement of the buried object can be one-dimensional, two-dimensional, or three-dimensional. By measuring the physical properties of each terminal, the damage location and the damage amount of the refractory can be evaluated with time.

If the terminals described above are buried in advance at the design limit depth of the furnace equipment, the terminal transmits a signal that detects the intrusion of slag to a safety circuit installed outside, so that the amount of waste input and combustion can be reduced. In addition to controlling the gas temperature and the like to an appropriate amount, it is possible to automatically stop the entire ash melting system in an emergency and prevent a serious accident from occurring.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A component of an ash melting furnace in which a terminal having a damage evaluation function is buried is manufactured according to the items described in the claims, and the claimed items are implemented.

<Example 1> A furnace wall material in a waste incineration ash melting plant was examined. FIG. 2 shows a structure of a terminal in which graphite is coated with a refractory and a furnace wall structure made of the refractory in which the terminal is embedded. The terminals are made of graphite with a shape of 5 mmφ × 10 mm and castable with alumina refractory (98 wt% Al ₂
O ₃ ) was coated 10 mm. In addition, a platinum lead wire was embedded in graphite and connected to measure the resistance of graphite.

85 wt% Al ₂ O ₃ -1 is used for refractories for furnace walls.
Using a castable of alumina-chromia refractory containing 0 wt% Cr ₂ O ₃ as a main component, pouring it into a mold, embedding the above terminals, naturally drying, heating and firing at 1000 ° C., and furnace structure with a wall thickness of 10 cm And

The orientation of the terminals buried in the furnace wall refractory is such that the terminals (A) to (D) are arranged at intervals of 1 cm in the depth direction so that the amount of erosion of the refractory can be evaluated stepwise. The tip of each terminal is 2cm from the outermost surface of the furnace wall material in the direction.
It was buried to a depth of 4 cm, 6 cm and 8 cm. The mixed ash composed of incinerated ash and fly ash was heated to about 1400 ° C. in a melting furnace having the above furnace structure to convert the mixed ash into molten slag.

Here, the composition of the incinerated ash is 30 wt% SiO
_{2 -15wt% Al 2 O 3 -15wt} % CaO-5wt% N
a ₂ O, fly ash is 40 wt% SiO ₂ -15 wt% Al ₂ O
The _{3 -15wt% CaO-5wt% Fe} 2 O 3 as main components. As a result, the furnace wall material is eroded by the molten slag and the terminal coating material is eroded, and the graphite is reduced in wear. As a result, the resistance value of each terminal changes with the operation time as shown in FIG. As a result, it was confirmed that the amount of erosion of the furnace wall material can be evaluated stepwise under the actual environment.

<Embodiment 2> FIG. 4 shows the structure of a terminal using a heat-resistant alloy hollow tube in place of the graphite used for the buried substance of the embodiment 1. A hollow tube having an inner diameter of 5 mm and an outer diameter of 6 mm was bent in a U-shape, and the buried portion was constructed and cast with the same castable as in Example 1. Circulate N ₂ gas at a constant flow rate in the pipe,
The flow rate was measured externally. The furnace wall structure and the arrangement of the terminals are the same as in the first embodiment. As the refractory is melted and the terminal coating material is melted and the molten slag flows out and solidifies in the pipe, the gas flow velocity in the pipe decreases as shown in FIG.
It was confirmed that the damage amount of the furnace wall material could be evaluated step by step.

Further, to measure the difference between the inlet temperature and the outlet temperature of the N ₂ gas, also by measuring the change in heat input to the N ₂ gas by thinning it is possible to predict the damage of refractories. In this case, in order to cancel the temperature fluctuation due to the operation mode, it is preferable to separately install the same hollow tube in the sound part to cancel the temperature difference change caused by the operation temperature fluctuation.

<Embodiment 3> FIG. 6 shows a structure of a terminal using a metal conductive wire as an embedded material. A 1 mm-diameter platinum wire having a buried portion constructed and covered in the same manner as in Example 1 is bent into a U-shape, and the current value is measured outside. The furnace wall structure and the arrangement of the terminals are the same as in the first embodiment. As the refractory melted, the coating material of the terminal was melted, and as shown in FIG. 7, the disconnection of the conductor was measured, and it was confirmed that the damage amount of the furnace wall material could be evaluated stepwise.

[0025]

According to the present invention, the terminals buried in the refractory constituting the equipment in the melting furnace are arranged at least one dimension.
By measuring changes in physical properties such as the resistance value, current value, and gas flow velocity of the terminal, the amount of damage to refractory equipment can be evaluated, so that waste melting furnaces, coal gasification furnaces, metal melting furnaces It is possible to improve the reliability of equipment made of refractory such as.

[Brief description of the drawings]

FIG. 1 is a side sectional view illustrating a configuration of a swirling ash melting furnace of the present invention.

FIG. 2 is a plan view showing a furnace wall structure in which a damage evaluation terminal is embedded.

FIG. 3 is a characteristic diagram showing a relationship between an ash melting furnace operation time and a resistivity of a damage evaluation terminal.

FIG. 4 is a cross-sectional view showing a structure of a terminal using a heat-resistant steel hollow tube and a furnace wall structure.

FIG. 5 is a characteristic diagram showing a relationship between an ash melting furnace operation time and a N ₂ gas flow rate at a damage amount evaluation terminal.

FIG. 6 is a plan view showing a structure of a terminal using a platinum wire and a furnace wall structure.

FIG. 7 is a characteristic diagram showing a relationship between an ash melting furnace operation time and a current value of a damage evaluation terminal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Char air inlet, 2 ... Melting furnace main body, 3 ... Furnace wall, 4
... slag tap, 5 ... slag cooling water bath, 6 ... slag outlet, 7 ... exhaust _{port, 8 ... Al 2 O 3 -Cr} 2 O 3 based refractories, 9 ... heat insulating portion, 10 ... anchor, 11 ... covering material ( Al
₂ O ₃ refractory), 12: graphite, 13: platinum wire, 14: heat-resistant steel hollow tube.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23G 5/027 ZAB F23G 5/50 R 4K056 5/50 G01N 13/04 G01N 13/04 27/04 Z27 / 04 B09B 3/00 302E 303K (72) Inventor Hironobu Kobayashi 7-1-1, Omika-cho, Hitachi City, Ibaraki Pref. Hitachi, Ltd. Hitachi Research Laboratory, Ltd. (72) Inventor Hideaki Utsuno, Ibaraki Prefecture Hitachi 1-1, Hitachi, Ltd. (72) Inventor Yoshitaka Kojima 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory, Hitachi Ltd. F-term (reference) 2G060 AA20 AE01 AF07 AG01 EA06 KA11 3K061 AA23 AC01 AC11 AC12 AC13 BA05 BA06 DA01 DA11 DB17 FA05 FA17 FA28 3K062 AA23 AB03 AC01 AC11 AC12 AC13 BA02 BA05 CA01 CB03 DA36 DA40 4D0 04 AA46 AA50 AB09 CA27 CA29 CA45 CC02 DA01 DA20 4G012 JG03 4K056 AA05 CA02 FA19

Claims (5)

[Claims] In a melting furnace for thermally decomposing a waste into a gas, pyrolysis gas is melted and solidified, wherein damage to equipment constituted by the refractory is detected by a change in state before and after passage of a medium moving inside the refractory. Refractory damage evaluation method. 2. In a melting furnace in which waste is pyrolyzed into gas and melted and solidified, the surface of the buried substance is coated with a substance having a different damage rate from that of a refractory used in equipment, and damage to the refractory can be detected. A method for evaluating the amount of damage to a refractory, wherein the damage is predicted using the buried terminal and the buried terminal. 3. A melting furnace in which waste is pyrolyzed into gas and melted and solidified, and the slag is infiltrated and melted by installing the buried object according to claim 1 or more in one or more dimensions parallel to the direction of damage. A method for evaluating the amount of damage to a refractory, characterized in that the loss can be evaluated stepwise. 4. A terminal made of a substance which comes into contact with and is damaged by slag and a gas atmosphere inside the refractory, and the change in the electrical, magnetic, thermal characteristics, etc. of the terminal is measured to thereby prevent damage to the refractory. A method for evaluating the amount of damage to a refractory, characterized by detecting the progress of fire. 5. A general garbage or industrial waste having a reliability improvement of a system by detecting damage to a component device made of a refractory by using the damage amount evaluation method according to any one of claims 1 to 4. A method for evaluating the amount of damage to refractories, which is used in melting furnaces for nuclear waste and steelmaking.