The main performance of industrial kilns is mainly determined by the technical and economic performance of refractories, which directly affects the investment cost, working performance, thermal efficiency and energy consumption of kilns. General principles for selecting refractory insulation materials such as insulating bricks:
- Kiln performance and thermal characteristics. For example, the furnace with intermittent work shall be made of materials with low heat capacity.
- Safe use temperature, heat conduction system, high temperature strength and chemical stability of materials.
- Service life.
- Investment cost and operation and maintenance cost.
Guide for selection of insulating bricks for industrial kilns
Generally speaking, heavy refractories focus on a certain technical performance index, such as high temperature stability, chemical stability, etc; The light-weight heat insulation materials pay more attention to the comprehensive technical and economic indicators of input and operation.
When selecting light insulating bricks, the thermal conductivity of insulating materials is generally used（ λ） Cost of insulation material per unit volume（ Ρ） To determine“ λΡ” The smaller the product of is, the better. The small value of thermal conductivity indicates that the thermal insulation material has good thermal insulation effect and low energy cost during operation. The low cost of thermal insulation materials per unit volume indicates that the investment cost is low and has a good investment economic effect. It can be selected by using the coordinate graphic method. The abscissa is the working temperature and the ordinate is（ λΡ） The curve of each material is intercepted by the safe use temperature of the material, and the material with good technical and economic performance is selected.
Attachment: construction method of kiln insulating brick
Thermal insulation engineering is a meticulous work. In order to make every link meet the quality requirements in the construction process, we must pay strict attention to precise construction and frequent inspection. According to my construction experience, I will talk about the relevant construction methods in the kiln wall and kiln top insulation work for your reference.
- Insulation brick masonry. The height, thickness and total length of the insulation wall must comply with the provisions of the design drawings. The masonry method is the same as that of clay refractory bricks, and the refractory mud is used for masonry. The masonry shall be fully grouted and the mortar plumpness shall be more than 95%. During bricklaying, it is strictly prohibited to knock the brick with an iron hammer, and the surface of the brick shall be gently knocked with a rubber hammer to align it. It is strictly forbidden to cut bricks directly with a gray knife. The bricks that need to be processed shall be cut neatly with a cutting machine. In order to avoid direct contact between insulating bricks and open fire in the kiln, refractory bricks can be used to build around the observation hole, and the overlapping bricks of insulating wall, insulating cotton and external wall shall also be built with clay refractory bricks.
- Thermal insulation cotton paving. The ordering size of insulation cotton board shall not only meet the design requirements, but also meet the actual needs of convenient installation. Attention shall be paid to during installation: the cotton boards must be in close contact with each other to minimize the joint clearance. At the cotton board joint, it is best to use high-temperature adhesive to make it tightly sealed to ensure its thermal insulation effect.
In addition, the cotton board to be processed shall be cut neatly with a knife, and it is strictly prohibited to tear it directly by hand.