The regenerator is the main body of the hot blast stove for heat exchange, and it is made of checkered bricks. The surface of the refractory brick is the heating surface of the regenerator, and the checker brick is the medium for storing heat. The characteristics of checker bricks have a direct impact on the heat storage capacity, heat exchange capacity and thermal efficiency of the hot blast stove.
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The requirements for the checker bricks are: the checker bricks per unit volume have a large heating area for heat exchange; there is a certain weight of bricks to store heat to ensure that the air supply cycle does not cause excessive wind temperature drop; can cause airflow disturbance, Maintain a high flow rate and improve the heat transfer efficiency to the fluid; after the checker bricks are stacked, the structure is stable, and there is no dislocation between the bricks.
The checker bricks currently used are block-shaped perforated bricks, which are perforated on the entire brick, and the hole types are round, square, rectangular, hexagonal, etc., and five-hole bricks, seven-hole bricks and 19-hole checker s are used more. brick. The advantages of block perforated bricks are that the built regenerator has good stability, fast masonry, and large heating area; the disadvantage is high cost. In order to cause airflow disturbance and increase the heating area, flanges are often added in the holes, or the holes are made to have a certain taper, and the rectangular holes can also be twisted 90° at 1 to 3 layers; in order to prevent dislocation in the horizontal direction, the upper and lower layers are refractory The bricks are matched with the mouth, and many manufacturers in my country have begun to use 19-hole checker bricks.
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The structure of the regenerator can be divided into two categories, namely, the single-segment type with constant cell cross-section over the entire height and the multi-stage type with changing cell cross-section. From the point of view of heat transfer and heat storage, it is more reasonable to use the multi-stage type. During the operation of the hot blast stove, it is hoped that more heat is stored in the upper high temperature section of the regenerator, so the upper checker bricks have a larger filling coefficient and a smaller cross-sectional area of the effective passage, so that the cooling will not be too fast during the air supply period, so as to avoid a sharp drop in the air temperature. In the lower part of the regenerator, due to the low temperature and low airflow velocity, the convective heat transfer effect is weakened. In order to improve the heat exchange capacity of the lower checker bricks, the better method is to use wavy checker bricks or checker holes with interchanging cross-sections. When the naan diameter is smaller, the hole shape can increase the degree of turbulence and improve the lower convective heat transfer. The regenerator is the most important part of the hot blast stove, and the quality of the masonry must be strictly required. After the installation is qualified on the grate, first level it with thick clay mud, the thickness is not more than 5mm, and some factories use mechanical processing to level it. The furnace operator does not use refractory clay. The first layer of checker bricks is built according to the grid holes of the furnace grate. According to the center circle of the grid hole of the furnace grate, two perpendicular cross center lines are drawn as the control lines of the checker bricks. Then start from the center to build a cross-shaped brick row, and then in 4 areas, build the cross-shaped brick row to the direction of the furnace wall in turn. After the first layer of checker bricks is laid, count the number of complete checker holes and make a record. In the future, all layers of checker bricks are dry-laid, and it is necessary to ensure that the checker holes are vertical. An expansion joint of 10~15mm is left between the edge of the checkered brick and the furnace wall, and the expansion joint is filled with straw rope or wooden wedge to prevent the checkered brick from loosening. After the whole checker bricks are laid, the checker bricks should be cleaned, and the number of clogging holes should not exceed 3% of the complete holes of the first layer of checker bricks.
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Checker bricks have two masonry methods: independent brick columns and overall staggered masonry. Independent brick-column structure, the tolerance requirements on masonry height are not too strict, and high through-hole ratio can be guaranteed after masonry, but the stability is poor, and it is easy to cause checker holes to tilt or twist after air supply; the staggered masonry method is the upper , The lower checkered bricks bite each other to make the regenerator form a whole masonry method, which can effectively prevent the inclined displacement of the checkered bricks. The overall staggered masonry has strict requirements on the tolerance of the checker brick itself, and must be carefully selected and classified before masonry. When designing checkered bricks, the size of checkered bricks should be a negative tolerance, generally 0~2mm.
Zhengzhou Shennan Refractory Co.,Ltd are professional in producing high quality checker bricks ,any demands,please don't hesitate contact with me.
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