JPS59174585A - Carbon adhesion preventive refractories - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refractory that can prevent the adhesion of carbon such as tar produced during dry distillation in a coke oven or the like, and can easily separate the adhering carbon. In manufacturing equipment that handles decomposition products of organic substances and dry distilled coal at high temperatures, carbon deposits such as tar substances may adhere to the equipment surface and accumulate in layers, significantly hindering subsequent operations.

For example, in coke ovens, many refractories are used not only for the oven body but also for the oven lid, etc., but carbon adhesion is noticeable, making it difficult to process after adhesion, especially scraping off accumulated carbon. I've been doing it.

On the other hand, at present, no effective method has been found that can prevent such carbon adhesion or easily remove stuck carbon.Recently, the application of mold release agents has been gaining momentum, but there is insufficient It has not yet reached the point where it is effective.

In view of these circumstances, the present invention has developed a refractory that is resistant to carbon adhesion and can be easily peeled off even if it does, and has successfully put it into use for preventing carbon adhesion.

That is, the present invention provides a refractory for preventing carbon adhesion, which is characterized in that a glaze layer made of low expansion crystalline glass is applied to at least a portion of the outer surface of the cordierite refractory.

By constructing such bricks, carbon adhesion is reduced in the coke oven and the furnace body in areas where carbon adhesion exists, and adhering carbon can be easily removed, as will be specifically explained below.

Refractories conventionally used for this type of use, for example, for coke ovens, have generally been silica or chamotite, but they are subject to significant wear and tear due to rapid heating and cooling, and are often repaired by spraying. - It is not a desirable material, but in recent years it has been
Quantity 02) Quality Similarity 1] Length l refractories are used. However, among these, bath-fused silica suffers from significant wear and tear due to cristobalite formation, and is hardly used. As described above, cordierite is commonly used at present, and At203SIO2 is used for some inexpensive applications.

The refractory of the present invention was therefore developed for the purpose of improving cordierite refractories, and is most suitable for this purpose, but it may also be applied to pond refractories.

The following cordierite refractories are suitable for use in coke ovens, etc. of the present invention.

0 structure 2Mg0-2At203-5s102 as the main crystal phase, and in addition to this, there are mullite (3At2osy2St02), Christopaley F (5I02), and the like.

0 Composition (wt%) At203,5102Mg0Fe20330-35 5
5□02. ! y-3,51,0~2.5◎Physical Properties Katsura 1 Specific Gravity 2.5~2.7 Bulk Specific Gravity 20~21 Apparent Porosity 18~22% Compressive Strength 325~346 kg/crn2 Coefficient of Thermal Expansion 0.27-0.30% (at 1000°C) The present invention is such a refractory to which a glaze layer is applied.

This glaze layer may be applied to at least a part of the outer surface of the refractory, but it is best to apply it to the entire surface facing the inner surface of the furnace or space, which is usually in contact with the anicarbon. A suitable glaze layer is one with a smooth surface that is less susceptible to carbon adhesion, and must be resistant to softening and melting at the temperatures at which it will be used. Also,
714 It is necessary that the material is unlikely to cause peeling 1 with the refractory to be glazed, and for cordierite refractories, it is better to have a similar low coefficient of thermal expansion.
In this respect, low expansion crystalline glass is suitable.

Preferred low expansion crystalline glasses are as follows: SiO2+ At206r Li2O, ZnO,'
20t contains Na2° as an essential component, SnO and B20.20 as optional components.
, F, etc. The specific proportions of these components are as follows. (Same as below for weight) i.e. 5io2 45-75% At205
'5~25Lt20
3 to 10 ZnO 10-27% to 20 and N20 0.5 to 5 The total of these is 95% or more.

These component ratios are within a desirable range in terms of meltability, crystallinity, and coatability, as well as to provide low-expansion crystals in relation to cordierite refractories, and the melting point is generally 1100~ A temperature of about 1200° C. is sufficient for use in coke ovens and the like for the purpose of the present invention. In addition, the linear expansion coefficient is 5 to 20X10/ at 700℃.
Peeling from the base refractory does not occur at temperatures around .degree.

In order to obtain the glazed large object of the present invention, such a glass frit is coated as a suspension or the like on a predetermined surface of a refractory by spraying, and then the melting point of the glass is lowered to below the melting point of the base refractory. This is possible by heating and melting at a temperature above and performing the desired crystallization treatment.In the present invention, this glaze layer is made of refractory material! It is desirable to apply the glaze to a thickness of 0.1 to 1.0 degrees. This is because it is difficult to form a uniform layer as a desk glaze layer, so the large base surface is likely to be exposed, and on the other hand, if it is too thick, it will easily peel off from the base surface. Therefore, the desirable range is about 0.3 to 0.7 mm. As described above, the main feature of the present invention is that by applying it, carbon sticks can be easily removed even if it sticks with force and force, and it can be used only in coke ovens. However, it can be used as a furnace material in places where there is carbon adhesion, but there are problems in scraping off the carbon, or it can solve the bad working environment if scraping is not done. However, it brings many benefits.

Next, examples will be described.

・Refractory structure Corsoerite main composition 5in258%, At20534%, Fe20
325%Mg0 3f) Assault, other 2.5% Apparent specific gravity 2.6-0 Bulk specific gravity 2. o6 Apparent porosity 20.8% Compressive strength (kg/z) 325 (Normal flow) Coefficient of thermal expansion 028% (1ooo°C) Glaze layer has lath frit composition 5IO248%, At2o515%, ZrO2o%
, r, t2oMK202%f 5n037%, 820
32%, F 1%) A slip obtained by adding approximately the same amount of water to a powder of OO Metsushi or less of the glaze layer frit was applied to two sides of the refractory brick, and dried. It was then placed in an electric furnace for recrystallization treatment.

Place 11! The conditions are 60011 after being held at 1200℃ for 2 hours.
:T was rapidly cooled, heated again to 80° C. and held for 2 hours, then the electricity was turned off and cooled in the furnace. In the obtained refractory, the glaze layer was a white layer approximately uniformly applied with a depth of about 0.05 cm, a melting point of 1175°C, and a coefficient of linear expansion of 9 x 107°C.

When these refractory bricks were then applied to a coke oven lid, the following results were obtained.

A glaze layer was applied to a portion of the furnace lid firebrick (14 out of 47 steps). When inspected 3 months and 2 months after operation, it was found that there was significant carbon adhesion on the walls of the refractory bricks made of metal glaze, but no carbon adhesion was observed on the walls of the refractory bricks in the construction area. It was shiny. After that, all of the furnace lids (47 steps) were replaced with glazed bricks, and when inspected 3 and 5 months later, no carbon was found and the bricks were shiny.

1 generation 3]! Person Tani Ll,l "1': Hiki! Continuation of page 1 0 Application Person Asahi Glass Co., Ltd. 2-1-2 Marunouchi, Chiyoda-ku, Tokyo

Claims (1)

[Claims] 1. A large-sized product for preventing carbon adhesion, characterized in that a glaze layer made of a low-expansion crystalline lath is coated on at least a part of the outer surface of a cornoelite refractory. 2 Low expansion crystalline glass composition is by weight, SiO24
5-75%tAt2035-25%, r, t2o 3
~10%. ZnO3, 0-27%, KO and or Na 200.5
~5%. The refractory for preventing carbon oxide build-up according to claim 1, wherein the other content is 3 to 15. 3 5n in weight% as other components of the low expansion crystalline composition
02 o, 2-10%, B2030.5-4%, F
The refractory for preventing carbon adhesion according to claim 2, which contains 0.3 to 3%.