- Time:Feb 20, 2023
In the cement industry, the energy consumed in the cement clinker to sintering production process accounts for more than 80% of the total energy consumption in the entire cement production process. 80% of the total energy consumption.
The kiln shell of the rotary kiln is made of steel. Due to the operating characteristics, it is impossible to use heat insulation materials for heat insulation, resulting in a large amount of heat dissipating from the kiln through the cylinder to the atmosphere, which seriously affects the overall heat utilization in the cement production process. efficiency.
In order to prevent the shell of the rotary kiln from being damaged by excessive temperature and ensure the safe operation of the equipment, the lining bricks of the rotary kiln should be replaced when about half of the use is made. The actual utilization rate of refractory bricks is only 40% to 50%, causing a large number of waste of resources.
In fact, due to the low thermal conductivity of cement clinker (about 1000°C, 1.2W/m·K), the firing zone can stick to the kiln skin during operation, and the temperature of the firing zone cylinder is not high. The hotter part is in the transition zone. Reducing the cylinder temperature of the cement rotary kiln, especially in the transition zone, can not only reduce the production cost of the cement industry, save fuel, but also improve the utilization rate of refractory bricks and promote the sustainable development of my country's precious refractory resources. important economic and social significance.
At present, there are many types of low-conductivity energy-saving composite alkaline bricks and silica bricks in the market. At present, the market has three multi-layer structures: Structure 1: Silica bricks are used for the working layer, and high alumina system + heat insulation board (aluminum silicate) is used for the non-working layer fiberboard, calcium silicate board, etc.). Structure 2: Silica bricks are used for the working layer, and high alumina system is used for the non-working layer. Structure 3: Silica bricks are used for the working layer, and heat insulation boards for the non-working layer (aluminum silicate fiber board, calcium silicate board, etc.).
These structures have certain effects on heat preservation and energy saving, but have the following disadvantages and hidden dangers. 1. The materials of the working layer and the composite layer are different, and the expansion coefficients are different. If the molding and sintering are not good, there will be defects inside the brick body, which will affect the use. 2. The thickness of the composite layer is about 65mm. When the working layer is seriously damaged in the later stage of use, it will bring greater risks to the normal operation of the rotary kiln. 3. The key to the heat insulation effect is whether the selection of heat insulation materials and the structural design are reasonable. (Structure 3) has limited effect on heat insulation.
Based on the above characteristics, the composite structure silicon molybdenum brick developed by ZHENJIN REFRACTORIES has made a composite structure with a certain shape and size on the non-working surface of the brick through a special molding method, and filled the composite structure with high-quality heat insulation materials. The two materials that make the functional properties different are clearly differentiated and closely combined on the working layer and the insulation layer of one brick.
On the premise of satisfying high temperature application and service life, composite structure silica brick has low thermal conductivity and shows good heat insulation function. The use of the 5000t/d cement production line of Weihui Tianrui Cement Company and the 5000t/d cement production line of Zhengzhou State Investment Xindeng Cement Co., Ltd. and other units has proved that the use of composite structure and low thermal conductivity silica molybdenum bricks can reduce the surface temperature of the cylinder by 80-120°C About, the production of one ton of cement clinker can save 1kg of standard coal, 5 tons of standard coal per day, and 1,700 tons of standard coal per year, which reduces the consumption of refractory bricks, improves the operating environment of the equipment, and extends the user cylinder and equipment The service life has gained considerable economic and social benefits.
