Lattice brick, this term may not be common in the daily life of ordinary people, but in the iron-making industry, it is widely recognized and accepted as a heat transfer and heat storage body with many superior thermal characteristics such as strong heat exchange capacity, large heat storage area, smooth ventilation, and low resistance. Rongsheng Checker Bricks, English name Lattice brick, is a heat transfer medium, mainly used in the upper and middle parts of the heat storage chamber of the hot blast furnace to store heat. In the process of heating cold air into hot air, lattice brick plays an extremely important role.
7-Hole, 19-Hole, 31-Hole and 37-Hole Hot Blast Furnace Checker Bricks
Checker bricks, the name may sound a bit mysterious, but it actually plays a very important role in industry. In hot blast furnaces, glass kilns and coke oven regenerators, it is like a passionate heat transfer messenger, helping hot and cold gases to complete heat exchange.
So, what is so special about checker bricks? First of all, its design is very clever, with bricks with grid holes arranged in an orderly manner. These grid holes allow hot and cold gases to pass freely, thereby achieving efficient heat exchange.
The characteristics of checker bricks are also quite significant:
Strong heat exchange capacity: can quickly transfer heat to cold gas.
Large heat storage area: store more heat and reduce energy consumption.
Smooth ventilation: ensure smooth passage of gas without affecting heat exchange.
Good volume stability: can maintain the shape even at high temperatures.
High-temperature load creep performance: the performance remains stable under high temperatures and high load.
According to the material classification, checker bricks can be divided into clay, high alumina, mullite, silica and sillimanite and other types. And according to the specification classification, there are 7 holes, 19 holes, 31 holes and 37 holes and other options.
Whether in hot blast furnaces, glass kilns or coke oven regenerators, checker bricks are an indispensable part. It not only affects the operating efficiency of the entire system, but also directly affects the safety and stability of production. Therefore, choosing the right checker brick is a crucial decision for every industrial producer.
The Volume Stability of the Hot Blast Furnace Checker Brick is Good
The checker brick has multiple transparent grid holes parallel to the side surface, as well as positioning protrusions and positioning grooves on two parallel surfaces. These designs not only make it ventilated smoothly and with low resistance, but also greatly enhance its heat exchange capacity and heat storage area. In addition, the checker brick has good volume stability, excellent high temperature load creep performance, high density and low porosity, which enables it to maintain excellent performance under high temperature and high pressure working environment.
Blast furnace hot blast furnaces usually adopt a checker brick regenerator structure, which transfers heat to the checker bricks by passing the high temperature flue gas after combustion through the holes of the checker bricks. Then during the air supply period, the cold air is heated into hot air through the checker bricks, and then sent to the blast furnace through the hot air pipe for combustion reaction. The aperture and heating area of the checker bricks have a direct impact on the performance of the hot blast furnace. The old blast furnace hot blast furnace uses standard checker bricks with an aperture of 40 mm and a heating area of 32.7 square meters per cubic meter. The Kalugin top-fired hot blast furnace uses checker bricks with smaller apertures and larger heating areas, such as checker bricks with an aperture of 30 mm and a heating area of 48 square meters per cubic meter, and checker bricks with an aperture of 20 mm and a heating area of 64 square meters per cubic meter. These improvements not only improve the thermal efficiency of the hot blast furnace, but also significantly reduce the amount of refractory materials used and investment costs of the hot blast furnace.
With the technological development of the ironmaking industry in the metallurgical industry, increasing the air temperature of the hot blast furnace has become an important measure. The technological development of the Kalugin top-fired hot blast furnace has enabled the maximum air temperature of the blast furnace hot blast furnace to reach 1350 degrees. Under this trend, 20 mm aperture checker bricks have become the first choice for modern hot blast furnaces due to their higher heating area and lower dosage. In blast furnace hot blast furnaces in Russia, China, Kazakhstan, Ukraine and other places, 20 mm aperture checker bricks have been widely used.
The application of checker bricks is not limited to blast furnace hot blast furnaces, it is also used in other industrial fields such as flame furnaces. According to different temperature zones and technical requirements, checker bricks of different materials are generally selected, such as siliceous checker bricks, clay bricks, high alumina bricks, mullite bricks, sillimanite bricks, etc. These checker bricks provide strong heat exchange and heat storage capacity for industrial production with their unique structure and performance.
In general, checker bricks have become an indispensable and important material in the ironmaking industry with their superior thermal properties and wide application fields. Its design and application not only reflect the continuous exploration and innovation of human beings in industrial technology, but also provide more possibilities and opportunities for our future industrial production. Contact Rongsheng for more information.
Refractory material manufacturer’s explanation of the heat storage area per unit volume of hot blast furnace checker bricks. Modern blast furnaces use regenerative hot blast furnaces, which are huge blast furnace blast heating facilities built up of checkered bricks. As a carrier of high-temperature heat, the working principle of checker bricks is to first burn gas, use the generated high-temperature flue gas to heat the checker bricks in the regenerator, and then pass the cold air through the hot checker bricks to be heated. The hot blast furnace alternately performs combustion and air supply, so that the blast furnace continuously obtains warm air. Therefore, improving the heat transfer efficiency of hot blast furnaces is of great significance to increasing the air temperature.
Heat Storage Area Per Unit Volume of Hot Blast Furnace Checker Bricks
To improve the heat transfer efficiency of the hot blast stove, the hot blast stove checker bricks must have excellent thermal properties. Using checker bricks in the design and increasing the thermal area of the checker bricks is an important technical measure to improve the heat transfer capacity. Comparison of the heat storage areas of several typical checker bricks below.
Traditional 7-hole lattice brick. The grid hole diameter is 43mm and the heat storage area is 38.1m2/m3.
7-hole grid bricks. The diameter of the grid holes is 30mm, and the heat storage area is 47.08m2/m3.
19-hole grid brick. The grid hole diameter is 30mm and the heat storage area is 48.6m2/m3.
31-hole grid brick. The diameter of the grid holes is 25mm, and the heat storage area is 58.1m2/m3.
37-hole grid brick. The diameter of the grid holes is 20mm, and the heat storage area is 68.7 m2/m3.
The practice has proved that under basically the same conditions, the air temperature of a large blast furnace can be increased by 38°C when using 19-hole bricks with a diameter of 30mm compared with traditional 7-hole bricks with a diameter of 43mm. Using 31-hole bricks with a diameter of 25mm in small and medium-sized blast furnaces can increase the air temperature by 19°C compared with 9-hole bricks.
RS Refractory Material Manufacturer is a powerful refractory material manufacturer. The quality of our refractory products is reliable and guaranteed. And our comprehensive customer service can also provide reliable quality assurance for our refractory products. The description of the heat storage area per unit volume of hot blast furnace checker bricks can better help companies purchase suitable regenerator checker bricks.
Application and requirements of checker bricks in hot blast furnace regenerator
Choose the appropriate size and thickness of checker bricks. When choosing the shape of checker bricks and the type of checker bricks, the following conditions and requirements should be considered:
① The quality of refractory materials.
② The degree of gas cleaning.
③ Different temperature conditions between the upper and lower parts of the hot blast furnace checker bricks.
④ It has high heat transfer efficiency and can increase the hot air temperature in a guaranteed amount.
Selection of checkered bricks for hot blast furnace regenerator
The regenerator of the hot blast stove is a space filled with checker bricks. Its main function is to use the internal checker bricks to exchange heat with high-temperature flue gas and combustion air. Therefore, as a heat storage and heat transfer medium, checker bricks should have a large heating area, high thermal conductivity, and quality to facilitate heat exchange and heat storage.
The main method to increase the heating area is to increase the number of holes in the checker bricks per unit area, so the number of holes in the checker bricks in the regenerator tends to increase. To improve the thermal conductivity of the material, black silica bricks are commonly used in Europe as checker bricks inside the regenerator. Because the iron oxide content in black silica bricks is high, it has high density, high thermal conductivity, strong heat storage capacity, and high heat exchange efficiency. Therefore, the upper part of the regenerator is made of siliceous check bricks, the middle part of the regenerator is made of low-creep high alumina bricks, mullite bricks, sillimanite, andalusite bricks, etc., and the lower part of the regenerator is generally made of clay bricks.
Modern regenerative hot blast stoves can basically be divided into two major types. The hood-type check bricks have a constant cross-section throughout the entire height, and the multi-section check bricks have varying cross-sections. The latter can be divided into three types, namely checkered bricks with alternating cross-sections, core-filled bricks, and brick wall surfaces with different roughness. Checkered bricks are available in a variety of shapes, such as square, rectangular, round, hexagonal, etc.
1) Multi-section checkered bricks. It was more commonly used in the past. The checkered bricks of hot air stoves are also of this type. The points of multi-section grid bricks are as follows.
(1) When the quality of the refractory material is poor, the upper checker bricks are easily damaged due to high temperature. This difficulty can be overcome by increasing the diameter and thickness of the upper checker bricks. Increasing the checker brick diameter reduces heat transfer and therefore prevents the upper checker bricks from overheating. Increasing the thickness of the checker bricks can reduce the average temperature of the checker bricks so that the load softening point of the refractory bricks is not exceeded, which prevents the checker bricks from softening and deforming. To protect the checker bricks from having sufficient compressive strength, the thickness of the upper checker bricks should generally not be less than 50~60 mm.
By taking the above two measures, the wind temperature will not drop too much. Weakening the heat transfer effect of the upper checker bricks also means slowing down the cooling of the upper checker bricks themselves. Therefore, towards the end of the air supply stage, the outlet hot air temperature drops less. Additionally, thin bricks heat up quickly and cool down quickly. Therefore, increasing the thickness of the upper checker bricks can reduce the fluctuations in the temperature of the checker bricks themselves and the blast temperature.
(2) The temperature of the lower checkered bricks is low, the convective heat transfer effect is weakened, and the radiation heat transfer effect is also very small. Therefore, reducing the diameter of the lower checker bricks increases the airflow velocity accordingly, which can significantly improve the lower convection heat transfer effect. In addition, corrugated checker bricks and checker brick cores can also be used in the lower part. This not only increases the heating surface and reduces the diameter of the checker bricks, but also promotes turbulence in the airflow, which is conducive to convective heat transfer.
The lower checkered bricks should not be too thick. Because in the continuous alternation between the air supply period and the heating period of the hot blast stove, the temperature of the center of the lower checker brick rarely fluctuates and does not play a heat storage role. At the same time, thinning the lower checker bricks can also increase the heating area of the lower checker bricks. Therefore, the brick thickness of the lower checkered bricks is generally only 25~40 mm.
Generally speaking, when using ordinary clay bricks, multi-section checker bricks are in line with the temperature conditions and heat transfer laws in the furnace. And it can make the blast temperature drop less. However, it makes the cleaning operation of checkered bricks very difficult and prone to clogging.
2) Covered segmented checkered bricks. Recently, due to the continuous improvement of the quality of refractory materials and to avoid the difficulty of dust-cleaning operations, more and more cover-type checker bricks have been used. Although it does not comply with the rules of heat transfer, due to the use of high refractory materials, the entire checker brick can be made of smaller checker bricks and thinner brick thicknesses, which can also increase the heat transfer coefficient to make up for the shortcomings.
With the improvement of gas depressurization work, the checker bricks can be gradually reduced. At present, China generally uses 80×80 mm checkered bricks. To ensure sufficient mechanical strength, the thickness of checker bricks should not be less than 50 to 60 mm.
Construction of Checkered Bricks for Hot Blast Furnace
Before laying checkered bricks in a hot blast stove, the grates and supports must be inspected. When inspected by the wire drawing method, the surface flatness deviation of the upper surface of the grate should be 0~5mm. The allowable deviation between the center line of the grate grid holes and the designed position should be 0~3mm.
The shape and size deviation of checker bricks should be accepted according to the relevant provisions of the current industry standard “High Alumina Bricks for Hot Blast Stoves” YB/T5016. Before construction, the usage plan should be determined based on the random inspection records of the dimensions of the checker bricks. Porous lattice bricks with tongues on the upper and lower sides should be layered according to height.
The grid hole at the center point of the regenerator should be used as the benchmark for determining the horizontal cross-center line control line of the brick grid on each layer. Each layer of grid bricks should be laid according to this horizontal cross-center line, and the grid holes should be kept vertical. During brick grid construction, wooden scales can be used to control the brick grid at the same time. During construction, a central control line should be established inside the surrounding furnace walls. The misalignment between the upper and lower brick grids should not exceed 5mm.
The surface of the brick grid should be smooth. The displacement of the brick grid holes to the furnace grate grid holes should not exceed 10mm, the complete number of grid holes should be counted and concealed engineering records should be filled in.
Expansion joints should be left between the surrounding checkered bricks and the furnace wall according to design regulations and should be fixed with wooden wedges.
Anti-scaling measures should be taken during construction and the grid holes must not be blocked. After the brick lattice is laid, it should be cleaned and the lattice holes should be inspected. If the bright light of the electric lamp can pass through the grid hole, or if the inspection steel drill lowered from above with a rope can pass through the full height of the grid hole, the grid hole should be considered qualified. The number of blocked holes should not exceed 3% of the number of complete holes in the layer brick grid. When using porous lattice bricks with upper and lower groove tongues for construction, the hole-blocking rate of the brick lattice does not need to be an inspection item.
When the brick lattice uses porous lattice bricks with groove tongues on the upper and lower floors, the upper and lower floors should be built with staggered joints and expansion joints should be left between bricks according to design regulations. The surrounding checkered bricks should be pre-processed and the arrangement diagram should be drawn in sequence.
To purchase hot blast stove regenerator checker bricks, heat storage hole bricks, and high thermal conductivity bricks, please contact us. We can provide high-quality refractory lining material products for high-temperature industrial furnaces. Our perfect customer service can provide long-life refractory materials for your high-temperature industrial furnace linings to save production costs.
With the advancement of the times, reducing consumption and improving production efficiency have always been the primary goals of major enterprises. In the field of high-temperature industry, regenerative industrial grid bricks are widely recognized and accepted as a heat-carrying and heat-storage body with many superior thermal properties such as strong heat exchange capacity, large heat storage area, smooth ventilation, and low resistance. Checker bricks are a heat transfer medium used in blast furnaces hot blast furnace regenerators, coke oven regenerators, glass kiln regenerators, etc. Checker bricks are usually arranged in an orderly manner in the regenerator. It plays the role of heat storage during the “burning period”. During the “air supply period”, the cold air is heated into hot air through convective heat exchange and radiation heat exchange.
Basic characteristics of regenerator checker bricks
It has a plurality of transparent holes parallel to the side surfaces, as well as positioning protrusions and positioning grooves located on the two parallel surfaces.
Good volume stability, excellent creep performance under high-temperature load, high density, and low porosity. Modern blast furnace hot blast stoves usually adopt a checkered brick regenerator structure.
Construction of Checker Bricks in Hot Blast Stove Regenerator
(1) The regenerator checker bricks usually use seven-hole checker bricks. During masonry construction, each layer should be arranged in a staggered manner, and the upper and lower grid holes should be aligned.
(2) The checkered bricks around the edges of the masonry and at the joints of the walls should be pre-processed according to the designed dimensions before masonry. During construction, the processed checker bricks will be laid in sequence according to the construction drawings. Be careful not to process checker bricks in the furnace. When building the wall of an internal combustion hot blast furnace with the furnace shell as the guiding surface, checker bricks can be processed appropriately in the furnace while taking protective measures.
(3) Before laying checkered bricks, the cross center lines should be drawn at the four angular directions of 0°, 90°, 180° and 270° of the wall masonry. Then pull out two rows of masonry center lines on both sides of the 90° and 270° lines, with the center column being the first row of masonry center lines.
(4) The checkered bricks on the first floor should be dry laid and laid in advance. The bricks can be laid formally after the center grid position is verified to be accurate and qualified. After the masonry is completed and it is confirmed that the surface flatness of the masonry meets the requirements, the second layer of checkered bricks will be laid.
(5) Each layer of checkered bricks is controlled according to the three rows of masonry center lines pulled out from the fence. Starting from the center line of each layer of checker bricks, lay the cross row of center bricks first. Then build the bricks along the four angles in the direction of the furnace wall.
(6) Allowable deviation of expansion joints between adjacent checker bricks
1) Clay checker brick: 4mm;
2) High alumina checker brick: 8mm;
3) Silica checker brick: 12mm.
Use yellow cardboard or foam plastic board to fill the expansion joint tightly. Before filling, process the board according to the reserved size and thickness of the expansion joint. Then when the checker bricks are being laid, the expansion joint plates are tightly attached to the sides of the checker bricks. Carry out simultaneously, build, and paste at the same time.
(7) After the first layer of checker bricks is completed, the processed checker bricks at the edge positions are laid in sequence. And check to confirm compliance.
(8) The expansion joint between the checker bricks and the furnace wall should be reserved according to the design and construction requirements. Use wooden wedges to wedge the expansion joint tightly.
(9) After the checker bricks are laid, clean the construction area. Check the hole position and smoothness of the grid holes again. If the electric light can pass through the grid hole or the inspection tool passes through the full height of the grid hole, the grid hole will be regarded as qualified.
Coke Oven Regenerator Checker Brick Construction Process
After the furnace body is completed, blow air to clean the secondary grooves on the roof of the regenerator. Mark the control line between the central partition wall and the sealing wall on the regenerator wall.
Blow the checker bricks clean with compressed air and start preparing to lay the checker bricks.
When the first layer of checker bricks is dry-layed, check the location and stability of the checker bricks before dry-laying the lower layer of checker bricks.
The checkered bricklayer after the second layer should be stepped back from the central partition wall to the furnace head.
Always check whether the holes of each layer of checker bricks are unobstructed, and the upper and lower checkerboard bricks should be aligned.
Yellow cardboard can be used to maintain the width and stability of the gap between the grid bricks and the regenerator wall and non-flammable materials must not be used for the padding.
After the dry-laying of checker bricks in each regenerator is completed and the inspection is qualified, the construction of the regenerator sealing wall begins.
The regenerator walls and checker bricks of divided regenerator coke ovens should be constructed alternately in sections. Before each section of checkered bricks is dry-layed, the section should be sealed or partitioned, and the wall grooves should be cleaned. During the dry-laying process of checker bricks, pay attention to prevent refractory mortar from falling into the lower checker bricks. Once the dry-laying is completed and inspected to be qualified, immediately cover it with a protective board. The protective board should be set firmly and tightly, close to the wall of the regenerator to prevent refractory mud from leaking into the checker bricks.
Hot Repair Method of Checker Bricks for Glass Kiln Regenerator
After long-term high-temperature operation of the glass melting furnace, the refractory brick for the glass kiln lining and various equipment used have aged to varying degrees. In particular, the checker bricks in the regenerator were seriously damaged and blocked, seriously affecting the atmosphere in the glass-melting furnace. This situation not only increases energy consumption but also causes a large number of quality problems in the glass products produced. Therefore hot repair of checkered bricks is by far the most effective way.
Thermal repair process of checker bricks in the regenerator
Hot repair preparation
Before hot repair, a specific hot repair plan must be developed. Equipment, tools, and checkerboard tiles should be ready for use. During hot repair, the ratio of raw and clinker should be adjusted, the pulling amount and pressure in the kiln should be controlled, and the temperature should be controlled to ensure the normal production needs of the furnace.
Replacement of checker bricks
After opening the regenerator, first clean out the old checkered bricks that have worn out inside. Special attention should be paid when dismantling old checker bricks, as the heat storage gradually decreases and the working conditions in the kiln change. The fire exchange should be manually controlled according to the situation and adjusted in time to ensure the hot spot temperature and melting.
Laying out new checkered tiles. The material of the regenerator grid bricks is the same as the original regenerator grid structure. It mainly uses three types: clay bricks, magnesia chrome bricks, and high-purity magnesia bricks. Layer clay bricks, magnesia chrome bricks, and high-purity magnesia bricks from bottom to top. Seal the thermal chamber door and withdraw the water tank. Seal the water tank door.
After the checker bricks in the regenerator are replaced and the door is sealed, it is very important to perform reasonable heating operations and monitor the temperature in the regenerator. During the entire heating process, the principle of “slow heating and no cooling” should be followed.
The effect of thermal repair of checkered bricks in regenerator
After the hot repair of checker bricks in the regenerator, the heat in the regenerator will be stable and the heat energy consumption will be reduced. Glass defects and frying time caused by material problems have been greatly reduced, and fuel consumption has been reduced.
Blast furnace technology is a critical aspect of the iron and steel production process. This highly specialized technology requires various components, including checker bricks, to operate at optimal performance. Checker bricks are a unique type of refractory material that plays a vital role in enhancing the performance of blast furnaces. In this essay, we will explore the importance of using high-quality checker bricks to maximize blast furnace performance.
Checker bricks are named after their unique checkered pattern. They are typically used in the lower portion of the blast furnace where they serve as a lining material. Checker bricks consist of a combination of carbon, silicon carbide, and alumina, which gives them high-temperature resistance and durability. They are designed to withstand extreme temperature and pressure conditions in the lower portion of the furnace and play a crucial role in enhancing the efficiency and productivity of blast furnace operations.
How to Maximize Blast Furnace Performance with Quality Checker Bricks?
One of the key benefits of using quality checker bricks in blast furnace construction is their ability to improve thermal efficiency. The lower portion of the blast furnace experiences some of the highest temperatures and pressures in the entire iron production process. Checker bricks help to regulate and control the flow of hot gases and materials through the furnace, ensuring optimal heating and combustion conditions. By regulating the flow of materials, checker bricks help to minimize heat loss and maximize thermal efficiency. This results in significant energy savings and improved overall blast furnace performance.
Another important benefit of using quality checker bricks is their ability to reduce downtime and maintenance costs. Blast furnace downtime can be costly, resulting in lost production and revenue. Checker bricks that are of poor quality or not designed for the specific conditions of the blast furnace can fail prematurely, requiring frequent replacement and maintenance. High-quality checker bricks are designed to withstand the extreme conditions of the blast furnace, minimizing the risk of failure and reducing downtime and maintenance costs.
Furthermore, quality checker bricks can help to improve the overall quality of iron production. The checker brick lining plays a vital role in ensuring that the blast furnace operates at optimal conditions, which results in high-quality iron production. Checker bricks help to regulate and control the flow of materials through the furnace, ensuring that the iron produced is of consistent quality and purity.
Checker Refractory Bricks Used in Blast Furnace
Checker bricks, checker refractory bricks blast furnace, is a checker brick with many advantages such as strong heat exchange ability, large heat storage area, smooth ventilation, and low resistance, which is generally recognized and accepted by the ironmaking industry in the world. Checker brick is a heat transfer medium used in the blast furnace regenerator. It is usually arranged in an orderly manner in the regenerator, plays a heat storage role during the “burning period”, and heats the cold air into hot air through convective heat exchange and radiation heat exchange during the “air supply period”.
At present, checker bricks, checker bricks blast furnaces, and checker bricks are mainly used in blast furnaces hot blast stoves, and flame furnaces. Checker bricks are mainly used in the regenerator of the hot blast stove. Checker bricks with grid holes in a certain structure are arranged in an orderly manner, and the upper and lower through holes of the checker bricks allow gas to pass through. According to the technical requirements of different temperature regions, silicon checker bricks, and clay bricks are generally used. In some hot blast stoves, there are also high alumina bricks, mullite bricks, sillimanite bricks, etc. to choose from. The function of the hot blast stove is to heat the cold air sent by the blower to the blast furnace into hot air. Then, the hot air is sent to the blast furnace through the hot air pipe for a combustion reaction. The blast furnace hot blast stove has a furnace firing period and an air supply period, and the rotation of the two task periods. During the firing period, the extinguished low-temperature flue gas passes through the holes of the checker bricks of the hot blast stove and transfers heat to the checker bricks. During the air supply period, the cold air from the blower enters the hot blast stove, is heated by the checker bricks to become hot air, and is sent to the blast furnace through the hot air pipe.
Clay bricks for hot blast stoves belong to a secondary category of silicon-aluminum series products. They are refractory products with an Al2O3 content of 30-48% made of clay clinker as aggregate and refractory clay as a binder. The refractoriness of clay bricks is comparable to that of silica bricks, as high as 1690-1730°C, but the load hardening temperature is more than 200°C lower than that of silica bricks.
In conclusion, maximizing blast furnace performance requires the use of high-quality checker bricks. These specialized refractory materials play a crucial role in improving thermal efficiency, reducing downtime and maintenance costs, and ensuring high-quality iron production. The use of quality checker bricks can result in significant energy savings, increased productivity, and improved overall blast furnace performance. It is essential to select the right type of checker bricks that are designed for the specific conditions of the blast furnace and to ensure that they are properly installed and maintained. By doing so, blast furnace operators can ensure optimal performance and maximize the efficiency of their iron production process. Buy refractory bricks used in blast furnace from Rongsheng.
