Thermal equipment used in ceramic industry can be divided into continuous operation and intermittent operation, and can be divided into flame type and electric heating type from the heat source used. Electric heating kiln is a kind of kiln that converts electric energy into heat energy, increases the temperature of products and completes the firing process according to the predetermined firing curve. Compared with flame kiln, it has special advantages, such as: it is easy to obtain high temperature above 2000℃, the kiln temperature can be controlled in a large range, and it is easy to realize action control; Because of burning different fuels, the pollution to the environment is small; In addition, it also has the advantages of simple structure and small floor space. Therefore, electrothermal kilns have been widely used in the ceramic industry, especially in the production and scientific research of special ceramics such as electronic ceramics and high-temperature ceramics.
Comparison between electric furnace and flame furnace
First, compare the basic principles of thermal engineering.
Flame kiln needs fuel combustion to provide heat, so it needs to calculate fuel combustion and combustion equipment; Fuel combustion needs to supply combustion-supporting air, and combustion products need to be discharged outside the kiln, so it is necessary to calculate the gas flow rate, flow resistance, changes of various pressure heads and ventilation equipment in the kiln. Electric heating kiln generally converts electric energy into heat energy through electric heating elements, so it is necessary to select electric heating elements, calculate the size of electric heating elements, and select calculation power supply and control equipment. Because there is no problem of fuel combustion, it is not allowed to consider ventilation equipment such as air supply and elimination of combustion products. In terms of heat transfer in the kiln, the flame kiln is mainly the gas radiation heat transfer and forced convection heat transfer of combustion products, while the electric kiln is mainly the solid radiation heat transfer and natural convection heat transfer of electric heaters, that is, the basic ways of heat transfer in these two kilns are different. However, if it is required to forcibly cool the products in the electric heating kiln or remove the gas generated during the product firing process, and maintain a certain pressure system in the kiln, it is necessary to calculate the ventilation equipment of the electric heating kiln, and there is also forced convection heat transfer in the kiln.
Second, compare the main advantages and disadvantages of structure and operation.
Electric kilns do not need combustion equipment, and generally do not need ventilation equipment. It has the advantages of simple structure, small floor space, compact heating space, high thermal intensity and high thermal efficiency. Products in the kiln are not affected by flue gas and ash, and the temperature is easy to control. Therefore, the firing quality of the product is good. The product can be heated in the kiln under any pressure (high pressure or vacuum) or special atmosphere, and the high temperature above 2000℃ which is difficult to reach in the flame kiln can be obtained.
Third, from the cost comparison.
Generally speaking, the equipment cost and operating cost of fuel kiln are low; However, the equipment cost and operation cost of electric heating kiln are high. However, as far as the atmosphere and temperature control in the kiln are concerned, the electric kiln is better. Ceramic products with small volume and high price, such as special ceramics or products that need controlled atmosphere treatment, tend to use electric heating kiln. In addition, in areas with abundant power resources, the electricity price is cheap, and electric heating kilns can also be considered.