The refractory brick lining of the kiln is the main structural part to bear the heat load. The main contents of the lining design are: correctly select the refractory materials and thermal insulation materials; Correctly form furnace wall, furnace bottom and furnace top structures; Determine furnace lining size; Correctly design the combustion chamber, smoke exhaust duct and other local structures of the furnace lining according to the thermal requirements of the furnace; Reasonably arrange the position and quantity of temperature measuring holes, peepholes, smoke exhaust holes, burner bricks and expansion joints; Select appropriate fixation methods of mud, binder or fiber products; Calculate the consumption of refractory materials, thermal insulation materials and building materials by item.

1、 General requirements for refractory brick lining design

When designing an industrial furnace in a factory or workshop, the structural form of brick masonry (masonry for short) shall be unified as far as possible, and shall be advanced in structure, reasonable in economy and reliable in use.

When designing the furnace lining, standard products shall be used as far as possible. When it is necessary to use special-shaped products or special products, construction drawings shall be prepared by ourselves. For the red brick structure of masonry, at least 10 # red bricks shall be used.

The vulnerable parts of furnace lining shall be designed to be easy to replace and repair. The joint between the furnace body foundation and the foundation of other relevant auxiliary equipment (such as the workshop flue interface, the furnace rear preheater foundation, etc.) should be left with a settlement joint of about 20mm, while the jointed masonry on the foundation surface should not be undercut, but should be left with a straight joint, which should be close to each other without filling mud.

Any light products, such as light refractory clay bricks and diatomite bricks, shall not directly contact with the underground soil. When the furnace bottom masonry has a large volume, crushed red bricks cannot be filled with simple methods to ensure the strength. In order to reduce the cost, semi red bricks can be used for masonry.

2、 Firebrick masonry size

The calculation dimensions of various refractory bricks, thermal insulation bricks and red brick masonry are generally adopted according to the following provisions.

1) The horizontal dimension of refractory brick and diatomite brick masonry with mortar joints is a multiple of 116mm, and the vertical dimension is a multiple of 68mm.

2) The horizontal dimension of red brick masonry with mortar joint shall be calculated according to the formula: 250n-10mm, where n is the multiple of half brick (0.5), and the vertical ruler is the multiple of 60mm, that is, the horizontal mortar joint is 7mm, and the vertical mortar joint is 10mm.

3) For the furnace wall composed of refractory bricks and red bricks, because the brick layer sizes of red bricks and refractory bricks are different, the size of red brick masonry shall be uniformly calculated according to the size of refractory brick masonry. In order to adjust the elevation, straight bricks such as Tz-2, Tz-3, and Tz-4 can be used for alternate masonry as required, but the size with mortar joints and the number of bricks used shall be marked in layers in the construction drawing.

3、 Reserve method for expansion joint of refractory brick masonry

In principle, expansion joints shall be reserved for the heated and expanded masonry layer by layer. However, when diatomite bricks or other insulating board materials are used as the outer insulating masonry, expansion joints need not be reserved for such insulating layers. The underground masonry of heating furnace and heat treatment furnace shall only be reserved with expansion joints for the inner layer (such as the inner layer of refractory bricks in the flue duct) in contact with flue gas. The size of masonry expansion joint shall be adopted according to the data listed in Table 8-63.

The masonry expansion joint shall generally meet the following requirements.

1) The width of each expansion joint shall be 5mm at least and 20mm at most.

2) The spacing between expansion joints shall not be greater than 2.5~3.5m.

3) The reserved expansion joint shall not damage the airtightness of the masonry, that is, the air flow in the furnace shall not directly contact with the external insulating bricks and steel plate shell of the furnace wall through the expansion joint.

4) The expansion joints of two layers of homogeneous or heterogeneous refractory layers shall be staggered, and the staggered distance shall not be less than 232mm.

5) The expansion joints at both ends of the arch crown are generally not left at the joint between the arch end and the wall. The expansion joint in staggered masonry shall be at least 3 arch rings away from the wall; The ring masonry shall be at least 2 arch rings apart. The vault is treated as a special case for a short time.

6) The expansion joints of each layer of furnace wall and furnace bottom shall be reserved in the form of "bow", the expansion joints of arch crown shall be reserved in a ring shape, and the expansion joints of staggered arch crown shall be reserved at the seam ring.

7) The size of all expansion joints shall be included in the total mortar joint size of the masonry, that is, the total size of the masonry is still a multiple of the calculated size of the brick.