Refractory material for petrochemical furnace

(1) Refractory materials for carbon black fuel furnace. In order to improve the production efficiency and the reaction degree, the reaction temperature must be increased in order to improve the production efficiency and the reaction temperature. If you want to produce hard carbon black, you must also improve the reaction temperature. In particular, the production of long life, rolling wear small tires will need a more rigid carbon black, the reaction temperature of 2000 ~ 2100, which requires more than the refractory.

(2) Slag gasification device. It is well known that the gas industry is widely used in refractories. The operating temperature and pressure of the refractory material used in the gasification equipment are extremely harsh, and the operation temperature and pressure are high: the slag belongs to the acid slag which has very strong corrosion resistance. At the same time, there is a highly corrosive gas. Refractory materials used for high resistance to acid slag corrosion can be used to obtain high life.

(3) The oil cracking unit: the operating conditions in the catalytic cracking unit are the most demanding operating conditions, including high temperature and high pressure. The refractory lining of the catalytic cracking unit is required to have high wear resistance and low thermal conductivity so that the two contradictory properties. Because of the high wear resistance generally requires high density, and low heat conduction rate generally requires a lower density, so it is needed to introduce the two properties of the material and its related problems.

This chapter mainly discusses and analyzes the fire resistance of these special applications in the petrochemical industry, and provides the basis for the development and application of the relevant refractories.

Brief introduction of refractories for blast furnace iron making

Blast furnace is the drum into the air the coke burning and reduction shaft furnace of ore smelting, is in high temperature and reducing atmosphere continuous iron making thermal equipment. In the last 20 years, the development of the global iron making technology is very fast, and the blast furnace is becoming more and faster. Nowadays, the life of blast furnace has been more than 15 years, the longest of which has reached more than 20 years. A new generation of service life of blast furnace will reach more than 20 years. With the furnace body design more reasonable, blast furnacerefractory materials are also continuously being developed and applied. Blast furnace lining refractory material needs more than any other process in the production of iron and steel. Refractory material to withstand high temperature thermal shock effect, wear and erosion of furnace charge, gas, the erosion of alkali metal, bosh following by molten iron and slag erosion, erosion. Therefore the problem of lining must be comprehensive consideration of various factors, selected according to the different parts of the cooling system of the furnace body and the different materials of the refractory material. In short, the selection of new high quality refractory materials is one of the important measures to prolong the life of the blast furnace.

The furnace body comprises a furnace body, bosh, belly, throat, hearth and bottom parts etc… The furnace with air, slag hole, taphole, cooling system and gas collector and charging device etc… Development trend of blast furnace refractorymaterials

Preparation and properties of refractory materials is an important aspect of the improvement of blast furnace lining system. With the increase in production of blast furnace, furnace lining refractory system should be able to withstand the severe wear. Lining refractory system is mainly to prevent high temperature chemical erosion and carbon bricks and iron directly contact erosion or melting loss. In any production conditions, to prevent lining cracks is the first step in the establishment of the good effect of lining system, the high temperature gradient and no enough space for expansion are two main reasons that cause cracks, reasonable preparation lining can prevent or reduce the cracks.

Production process of high alumina brick

It is well known that high alumina brick is one of the most widely used refractory materials, and high alumina bricks and clay bricks are the same as the basic same method. The process of crushing, mixing, molding, drying, sintering, and testing, packaging, etc.. The production practice shows that the high alumina clinker in the crushing before the strict selection and classification, low temperature and its pressure to withstand a good but high temperature, a slight reduction in the kiln, and the 1 meters, while the silicon brick can be as high as 1.7 meters. There are only some process parameters to be different. And classification of storage using bauxite and clay together with fine grinding method can improve the quality of products.

Raw materials and technology: mineral mainly consists of Mo mullite and corundum phase and blast furnace with corundum mullite brick using artificial electric melting or sintering corundum and Mo mullite raw materials as the main raw material, through high pressure shaping and high temperature sintering, mineral mainly consists of mullite. Features: the products have apparent porosity rate is low; load softening point, high creep resistance and chemical corrosion resistance excellent characteristics. Features: the product has the appearance of white, size accurate, with excellent high temperature physical properties and resistance to chemical erosion. Uses: mainly used for blast furnace bottom and hearth, is one of the advanced large blast furnace and ceramic cup material.

High alumina brick and clinker clay brick production process is similar differences. Uses: large blast furnace with advanced ceramic cup “one of the materials and hot blast stove industrial furnace in high-grade refractory material can be used. Raw materials and technology: blast furnace with mullite brick using artificial electric melting or sintering Mo mullite raw materials as the main raw material, through high pressure shaping and high temperature sintering is ingredients in a higher proportion of clinker can be as high as 90% ~ 9% clinker before breaking for classification is chosen, screened in addition to iron firing temperature is higher, such as high alumina brick tunnel kiln firing average 1500 ~ 1600 DEG C.

Requirements of refractory materials for blast furnace lining repair

Furnace lining maintenance method generally speaking, there are grouting lining, cold spray technology, furnace shell hole opening technology and remote control technology.

Grouting lining technology can be widely used for the focus of a short-term fix shaft and Bosh area. It is a means of prolonging the life of, but must be in certain conditions repeat construction to maintain the thickness of the lining. Different furnace body parts of the use of refractory materials are also different, the pressure of mud to the success of the grouting technology is crucial.

The advantage of cold spray technology is that the inner wall of blast furnace can be cleaned thoroughly. And can make the bond between old and new refractory materials is better, and it can form well lining structure, make the blast furnace smooth, but the technology has the shortcomings of long time-consuming.

The furnace shell hole with the lance gunning is commonly used in the damaged lining furnace shell holes, with a lance from the outgoing furnace damage parts of spray repair. This methodcan be used to spray up speed, and the short time is short, but it is only suitable for the local damage.

Remote control is the use of the advanced technology in the development of blast furnace at home and abroad in recent years, remote control need time is short, wide range, but the technical control complex.

Grouting lining technology requirements of refractories consistency must be appropriate, for cold spray repair, furnace shell hole using guns gunning and remote control gunning, refractory materials under high temperature and normal temperature attachment is good, can continuous rapid formation of a certain thickness of coating layer, spray coating tightly bond into a dense and do not fall off, fast drying and warming.

What is the high aluminum cement castable

The main mineral of high alumina cement as calcium aluminate (CA), the hydration speed, and precipitation of calcium hydroxide. Therefore, high alumina cement prepared with the characteristics of the fire resistance of the fast hardening and high strength. Fireclay and high alumina clinker or with the same material waste refractory bricks, which is normally used in refractory aggregate and powder material, the maximum temperature for 1400 DEG C. Under normal circumstances, high alumina cement dosage is about 15%. When the temperature is high, it should be used to reduce the amount of cement, at present, the amount of cement in low cement pouring material is reduced to about 3%, so that the content of cement and powder is kept at about 30%. The refractory powder plays a role of filling in the pores of the aggregate and participating in the solid phase reaction at high temperature. Therefore, it is required to be as thin as possible. The varieties shall be in the same or slightly better aggregate, and shall not be used in place of the refractory mortar materials. The refractory need to be chosen according to the different service temperature, should not one-sided pursuit of high grade material, to turn material resources to good account. The maximum particle size of the refractory aggregate is generally 15mm. When the temperature is high, the particle size can be reduced. The particle size distribution of aggregate, usually used in the two grade ingredients, can also be used in the same material, the sand rate is generally 0.45~0.55 to control. Water quality can be expressed as a percentage of the amount of water, and it can be expressed as the amount of water to be used to be used to say that the amount of water in a water cement ratio or the. But the general principle is: in the case of the fire resistance of the mixture and the workability, should try to reduce the use of water. In addition, high alumina cement refractory pouring material can also be mixed with additives (such as water reducer, etc.) in order to improve the construction performance and improve the fire resistance.

The reason for surface cracks of refractory bricks after used a period of time

Although the fire brick is good, the structure is relatively stable, but the  refractory  brick used for a period of time, some customers reflect the surface of the refractory brick cracks, which is what causes it? After many years of research and experience, the main reason is that the surface of the refractory brick is four points. Today’s technical staff for you to read.

1, the raw material itself is dry and sensitive coefficient

The drying coefficient of raw material is the possibility of cracking of the product, the higher the drying coefficient is, the more easily the product is cracked, the lower the coefficient is, and the more difficult the product is. So we must be careful when choosing raw materials, as far as possible to choose dry sensitive coefficient of raw materials.

2, inappropriate production measures

Production without attention to the ratio of raw materials, if the mix is not uniform will cause the product crack, which requires us to pay attention in the production of the source, to avoid cracking in the future.

3, dry reasons

The air temperature is too high, and the furnace preheating is too short and the ventilation quantity is too large, so the reason of the crack is caused by the fire.

4, roasting reasons

A gate is not reasonable, the fire cooling too fast, too fast, will lead to uneven heating, it will cause cracks in refractory brick.

Above brick appear on the surface of the crack by Xinmi Changxing refractory to provide you with, more on the refractory brick consulting; please pay attention to our website.

Clay bonded castable refractories

Clay bonded castable refractory system combined with clay (i.e. soft clay as binder, its working principle is by clay alkali replacement given construction, high temperature is formed ceramic combination, and generates acicular mullite, interspersed with each other, compact structure,
high temperature and good performance.

Clay alkali replacement is in the mud and clay, when adding a thicker water film of metal ion, hydrogen ion replacement clay colloid diffusion layer, the diffusion layer thickness, increase the potential, increase the clay particles are negatively charged and improve the fluidity of the slurry can be poured to construct; when adding metal ions with thin water film, replacement of water film thickness of metal ions, the role and the opposite, the fluidity of the slurry and reduce the flocculation, resulting in clay bonded castable hardening. The former, commonly known as the glue solution or water reducing agent is widely used substances containing sodium ions, such as sodium tripolyphosphate; the latter, known as flocculent and coagulant, general use of lime and Portland cement, aluminates cement and magnesium hydroxide containing substances of calcium and magnesium ions.

It should be pointed out that when the clay bonded with the refractory castable is prepared, the adhesive agent and coagulant are added simultaneously and interact with each other. In order to make clay solution of glue and convenient construction and promoting hardening and the formation of strength, so we should choose delayed coagulant and dosage should be appropriate.

Clay bonded castable refractory material is mainly used in heating furnace, soaking pit and iron ditch and other thermal equipment, and display the superiority. However, its normal temperature and pressure strength is low, and the dry strength is not high. To this end, in the preparation of clay with refractory cast material, mixed with a small amount of advanced refractory superfine powder and other additives, made of high strength clay bonded with refractory. In addition, it is also developed to combine with the light of the light refractory, and can be used directly in the working layer of the flame furnace.