How to choose the different parts of the refractory lining of blast furnace

In the process of production and in the selection of various parts of the refractory lining, should follow the principle is: the refractory lining to correspond to the parts of the heat flow intensity, to keep under the impact of strong heat and lining can still maintain the continuity and stability of the cone. Each part of the refractory brick selection method is:

(1) Furnace throat. The main burden to withstand the impact and abrasion, generally used steel brick or water cooling steel brick.

(2) The upper shaft. Analysis of reaction of carbon 2CO2-CO + C easy happening areas is the site and alkali metal, zinc vapor erosion also occurred in this area. Plus the burden descent and ascending gas flow of scour and wear. Therefore, we should choose resistance to chemical erosion and abrasion resistance of refractory materials, the most appropriate is high relative density brick, high density, high aluminum brick or phosphoric acid impregnated clay brick.

(3) And lower body in the belly. The main mechanism of damage is thermal shock, high temperature gas scouring, alkali metals, zinc and carbon deposition, and chemical erosion of the initial slag. Should the lining refractory material thermal shock, resistance to slag erosion and erosion protection.

1000m3 and the following blast furnace can be used for aluminum carbon brick.

(4) Bosh. Hot gas erosion and iron slag erosion is the main reasons for the damage, this part of the heat flux intensity, refractory material life not long (as long as 1-2 months short 2-3 weeks), generally used in refractory degree is high, load softening temperature is high and the volume density of refractory material, such as the high aluminum brick, alumina carbon brick.

(5) Hearth tuber. This site is only in blast furnace of oxidation reaction area, high temperature up to 1900~2400 DEG C, lining by damage caused by high temperature thermal stress. Composite brick masonry hearth tuyere zone is adopted by the modern blast furnace, material for high alumina, corundum Mo mullite; corundum and silicon nitride combined silicon carbide, useful also hot pressed carbon block.

(6) The lower part of the hearth and bottom. The high thermal conductivity, resistance to penetration of high, resistance to chemical attack high, porosity, micro aperture of hot pressing small carbon bricks, micro porous carbon brick, hot semi graphite carbon brick and ceramic cup brown corundum or gray corundum brick etc. by this part of the refractory material. Taphole area work condition is bad, now the hearth refractory material matched with iron composite brick masonry, used in the production of carbonaceous, semi graphite G-Sic, Mo mullite, SiC material.

Characteristics of refractory brick

Refractory brick is made of refractory clay or other refractory raw materials. Light yellow or brownish. Refractory brick is a refractory material with a certain shape and size. According to the preparation process to divide can be divided into firing brick, brick, electric melting brick, and refractory insulating brick; according to the shape and size can be divided into standard brick, brick, and type specific brick.

Refractory bricks can be used as building materials and structural materials for building furnaces and various thermal equipments, and can be subjected to various physical and chemical changes and mechanical effects at high temperatures. For example, refractory clay brick, high alumina brick, brick, brick etc… Refractory brick is one of the most widely used products, so it has the characteristics of what kind of it?

1, chemical composition: the main components of the quality and characteristics of the decision to fire brick.

2, bulk density: the unit volume weight, the density is big, that the fire brick density is good, the intensity may be high, but the thermal conductivity may be big.

3, apparent porosity: no specific requirements, but as a refractory brick manufacturers muststrictly control the apparent porosity.

4 and refractoriness under load: also called high temperature load to deformation temperature, this parameter is very important, resistance to high temperature resistance of refractory bricks.

5, thermal shock resistance: resistance to temperature changes and not the ability to destroy.

6, the compressive strength: bear (normal temperature) the maximum pressure capacity of 7, flexural strength: the ability to withstand shear stress.

8, linear change rate: also called reheating linear change or residual line change, firebrick every time at the same temperature production quality.

How to use refractory bricks to build a drying machine

Drying machine trough, most of the use of iron trough, due to iron chute under the high temperature environment and the material erosion, often corrosion and sealing off, not only affect the production and not easy to maintenance, especially using boiling furnace factory is obvious). The Henan Changxing refractories factory is proposed under the trough using refractory brick masonry, and achieved good results, for reference.

Masonry materials: there are generally two kinds of refractory brick (T – 3, T – 19 or T – 38).

Masonry method: in the furnace near the dryer section, the center line of the dryer is a center, a small hole, the hole of the width, height and length of the drying machine feeding port size to determine the size of the. As with diameter of 1.5m x 12m drying machine, for example: the machine into feed inlet diameter 1000mm, this hole width desirable 800mm, hole height for into the outlet of 2 / 3 length from the drying head count, brick is the dryer in the rotation can’t touch bricks as the beginning. Hole pier to furnace direction extending about 800~1000mm. It into a small hole, hole at the center of the above built a tilted 45 degrees, 300mm wide groove can be in again. During the production, from the conveyor to the top notch pipe butt on it.

The results show that the use of refractory brick masonry dryer material tank has thefollowing advantages:

The high temperature, compressive strength, corrosion.

After the II masonry, brick almost to the outer edge of the dryer are all covered, drying head is not easy to burn, deformation, and prolongs the service life of the dryer.

(3) The fire heat and energy concentrated walk toward the middle, eliminate the air leakage and material leakage phenomenon, the flame in the hearth into the drying machine is very far.

Also such masonry method and on into the air without any effect, but without anything blocked, the slot into the fire hole effect is more ideal. The transformation of this groove is less; l ~ 2d can be completed.

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.