KR890004288B1 - Method for producing buring tube - Google Patents

Abstract

A burner tube is manufactured by moulding a slurry at 60-400 mmHg absolute pressure and demoulding, drying and sintering at 1200-1300≰C. The slurry is prepared by mixing 1-5 wt.% ceramic fiber, 1-10 wt.% filler (e.g.refractory clay, kaoline, diatomite), 1-15 wt.% inorganic binder (e.g. silica sol, alumina sol), 0.002-1 wt.% organic binder (e.g. sodium carboxyl methyl cellulose, sodium alginate) to water. The burner tube has a good insulation, light weight and long lifetime.

Description

Manufacturing method and composition of top down combustor

The present invention relates to a method and a composition of a new top-down combustor combustor having improved physical and chemical properties such as heat insulation and heat resistance in a combustor combusting briquettes, granulated coals, and lumps of coal produced by coal.

Conventionally developed combustion cylinders have mainly used refractory clays, but have a disadvantage of being easily destroyed as the bond structure of the earth gradually becomes weak due to the thermal shock caused by rapid temperature changes and the weak effects of sulfur dioxide and carbon monoxide.

Moreover, there is a disadvantage that the combustion effect is not sufficient because the heat insulation effect is weak and the heating effect is not good.

In addition, a mixture of cement, clay, and asbestos was produced, but heat resistance and durability have not been greatly improved. Many briquette combustors, such as a top-down briquette combustor, have been devised, but the problem that the combustion cylinder is easily broken due to thermal shock due to the high heat reaching the maximum rising temperature of briquette combustion 1300 ° -1350 ° C has been derived.

Therefore, the present invention is a ceramic fiber filler (Filler: refractory clay, refined kaolin, diatomaceous earth, cordierite, etc.) and inorganic binder (Binder: alumina sol, silica sol) and organic binder [Binder: Sodium Carboxyl Methyl Cellulose (CMC) , Methyl Cellulose, Sodium Alginate, Hydroxyethyl Cellulose], etc., are mixed with water to form a clot, and then molded and dried in a vacuum molding mold to be fired at a high temperature. Therefore, it is aimed at drafting a top-down combustion cylinder having excellent physical and chemical properties since the heat retaining function is always maintained in the combustion cylinder.

In the present invention, the ceramic fiber is cut into 1-10 mm, preferably 2-5 mm, followed by mixing and stirring the filler, the organic binder, and the inorganic binder while sufficiently dissociating in water. At this time, as the filler, refractory clay, refined kaolin, diatomaceous earth, cordierite, organic binder, sodium carboxyl methyl ethyl cellulose (C.M.C), methyl cellulose, sodium alginate, hydroxyethyl cellulose, inorganic binders, alumina sol, silica sol is preferred.

The above-mentioned role of the organic binder (Binder) plays an important role in maintaining moldability at room temperature, but it is preferable to use as small amount as possible. When the amount of the organic binder is large, the shrinkage rate during firing increases, so it is preferable to use a small amount of a relatively high viscosity, and it is not necessary to use it when the moldability of the filler or the inorganic binder is sufficiently maintained. .

Inorganic binder (Binder) plays an important role in maintaining the bonding force at high temperature and forming the formability and serves to maintain the appropriate strength.

However, when the high temperature thermal shock and briquettes are newly replaced, the bond strength of the combustion tank is weakened by periodic repeated contact of sulfurous acid gas, carbon monoxide and water, and thus tends to crack or crumble.

Filler (Filler) has a low organic matter content, the average particle size of 0.1-10μm is used. These fillers bind the short fibers of the ceramic fiber after molding, and when dried at a high temperature of 1200 ° C-1350 ° C, they form mullite at high temperature to magnetize, and organic matters are carbonized and removed, forming a non-uniform matrix. )

Therefore, unlike simple bonding of inorganic fiber binder (Binder) of ceramic fiber of Korean Patent Publication No. 84-1884, the bonding force is increased by densification by strong sintering reaction. Does not appear at all, heat insulation and heat retaining function of the ceramic fiber with a certain level of pores in the porous tissue to maximize the thermal efficiency, enabling effective combustion and top-down combustion.

Specific combustion cylinder manufacturing process of the present invention is as follows.

1-5% by weight of ceramic fiber 1-10mm long (preferably 2-3%), 1-10% by weight of filler having a particle size of 0.1-10μm, (preferably 3- 5%), inorganic binder 1-20% by weight (preferably 5-10%), organic binder (Binder) 0.002-1% (preferably 0.02-0.5%) with a high speed stirring mixture All solids are completely suspended.

The agitation time is related to the stirrer speed and stops without the suspension precipitated with milk. Into the prepared suspension, a molding mold (Mold) with a vacuum device is injected and sucked into the mold by a vacuum pump to maintain an absolute pressure of 60-400 mmHg. At this time, the bonding is made between the ceramic fiber and the clay by the decompression force, the inorganic binder and the organic binder, and the molding is maintained.

Ceramic fiber is finely chopped and the filler (Filler) particle size is small, ceramic fiber and filler (Disperser) is well dispersed and formed a dense structure by the pressure reduction force.

At this time, if the absolute pressure is more than 400mmHg, the density of the tissue is lowered, the strength is weak, and the pores are too expanded to obtain the desired characteristics, and if the absolute pressure is less than 60mmHg, the density of the tissue is too dense, the pores are less Insulation, warmth and durability are a concern, so always maintain a pressure of 60-400 mmHg.

When the molded article obtained as described above is put into a high-temperature firing furnace and sintered at 1200 ° C.-1350 ° C., a porous combustion cylinder for a top-down combustor for the purpose of the present invention is obtained, and the composition of the completed combustion cylinder at this time is as follows.

50-95% of ceramic fibers, 5-40% of fillers, 1-20% of inorganic binders (Binders), and organic binders added during mixing molding are almost completely lost in the drying and sintering processes. An embodiment of a method of producing a combustion cylinder (crucible) suitable for a top-down combustor is as follows.

Example 1

200kg of water, 5kg of ceramic fiber 5kg with average length of 5mm, 10kg of refined kaolin with an average particle diameter of 1μm, 8kg of alumina sol, CMC 50, stirred with a high speed stirrer, and injected into the suspension a mold with a vacuum pump installed. After maintaining the thickness of the molded body is attached to about 20mm, take it out and roll it after demolding.

The molded product was put into a high temperature calcined earth and sintered at 1200 ° C.-1350 ° C. for 3 hours, and the results were as follows.

200kg of water, ceramic fiber 5kg, cordierite (average particle diameter 5μm), 10kg, silica sol 10kg Methyl Cellulose 100g is suspended with a high speed stirrer, put a predetermined mold in the suspension to maintain the absolute pressure 200mmHg and then thickness If it is about 20mm, take it out and dry after demolding.

The molded product was put into a high-temperature firing furnace and sintered at 1200 ° C.-1350 ° C. for 3 hours, and the results were as follows.

Example 3

5kg of ceramic fiber, 10kg of clay (average particle size 2μm), 10kg of silica species and 100g of sodium alginate were added to 200kg of water, and the experiment was carried out in the same manner as in (Example 2).

The above results are summarized in the following table.

As shown in the above table, the weight of the present invention was light in about 1/6, and the thermal conductivity was reduced to about 1 / 4-1 / 8. Since the generation of unburned dust is reduced by more than 50%, the use of the present invention can prevent the loss of anthracite coal of more than 1 million tons per year, based on the total amount of coal briquettes used in Korea. Prompt implementation dissemination is required.

In addition, the combustion duration of briquettes is extended by about 20%, and the heat dissipation that is not needed externally is increased, so the amount of heat that can be used as actual heating heat increases, so the briquettes with the same calorific value can greatly improve the heating effect. 4000Kcal / kg It is expected that it will be an opportunity to prepare a plan to enable the development of low-grade coal mines in Korea by completely burning low-grade briquettes.

Until now, only the high calorific value coal was capable of top-down combustion by the above-described insulation performance, but the present invention enables the top-down combustion of low-grade coal as well as the existing general briquettes by the high insulation and thermal insulation performance.

Since the fiber is firmly bonded in the clay sintered body, the life is semi-permanent and the weight is light even under adverse conditions such as toxic gas, high temperature, humidity, impact, etc.

In particular, considering that the maximum rise temperature of the central part is 1300 ° C.-1350 ° C. when the briquettes are burned, the product of the present invention is already calcined at a high temperature of 1350 ° C. for several hours, and thus no cracks or fractures due to thermal shock occur. It can be seen that durability is almost permanent.

Claims (1)

Mix and stir 1-5% of ceramic fiber, 1-10% of filler, and 1-15% of inorganic binder in weight ratio with respect to water, and inject this type of combustion cylinder mold into the turbid liquid to obtain an absolute pressure of 60-400mmHg. In the method of manufacturing a combustion cylinder which is demolded and dried at a high temperature of 1200 ° C-1350 ° C after molding under reduced pressure of 10 ° C., a top-down method of mixing and stirring 0.002-1% of an organic binder is stirred for complete turbidity. Method for producing a combustion cylinder for a combustor.