Four Measures to Reduce Energy Consumption of Brick Burning | Brick Technology
The combustion of fuel
As we all know, the combustion process of fuel is an oxidation process, and in this oxidation process, a large amount of heat is generated. All the fuel involved in the combustion is completely oxidized under the condition of sufficient combustion air, which is called complete combustion. Obviously, under the condition of complete combustion of fuel, there are no combustible components such as carbon monoxide, methane, hydrogen, sulfur vapor, etc. in the produced flue gas. If it is a solid fuel, the residue does not contain residual combustible substances, and the incomplete combustion of the fuel means that the heat in the fuel is maximized.
One condition that differs from complete combustion of fuel is incomplete combustion of fuel. The so-called incomplete combustion of fuel means that the fuel that participates in the combustion fails to fully utilize the heat of its content. There are two possible situations for incomplete combustion: one is that the flue gas contains combustible gas; the other is that the residue contains residual combustible substances.
The former can also be called incomplete combustion of gas. It is caused by the insufficient amount of air necessary for combustion, resulting in insufficient oxygen for the chemical reaction of the fuel, incomplete chemical reaction, and only part of the combustion reaction of carbon. The latter is also known as solid incomplete combustion. The reason is that although the amount of air is sufficient, the fuel is not fully contacted with the air, resulting in insufficient local air, resulting in incomplete combustion.
2. The kiln should have good heat exchange conditions
The process of burning bricks in the kiln is the process of heat exchange between the green body and the heat generated by the combustion of the fuel in the kiln. The temperature at which the chemical reaction of the components is carried out, so that the chemical reaction is complete, and the green body is fired into a brick. Oxygen is required for fuel combustion, and this part of the oxygen is brought to the firing zone by the preheated air flow through the cooling zone, and the high-temperature hot air promotes the combustion of the fuel. The heat released by the combustion of the fuel is to be transferred to the green body. The high-temperature hot gas is the medium for heating the green body and is one of the main heat transfer methods in the kiln.
The fired high-temperature products need to be cooled to room temperature in order to leave the kiln, and the heat is taken away by the cold air flowing into the kiln. The wet blanks in the preheating zone discharge residual moisture and the dry blanks continue to preheat and heat up, still relying on the hot flue gas flow from the firing zone. Therefore, when the green body is fired in the kiln, it cannot be separated from the flow of gas for a moment.
3. Adopt a reasonable method of blanking
The purpose of stacking blanks is to form stacks suitable for firing requirements. Which coding method is used to form stacks depends on the flow law of gas in the kiln. Factors such as the conditions of the kiln and the kiln exhaust equipment, and the requirements for the combustion conditions of the fuel are determined. The importance of stacking blanks is that, under certain equipment conditions, once the blanks are formed, the ventilation volume in the kiln, the uniformity of ventilation in all parts of the blanks, the distribution of internal fuels in the kiln, the combustion conditions and dispersion of external fuels, etc. As long as it is generally determined, the firing conditions in the kiln are basically determined.
As we all know, in the kiln firing process, the gas in the kiln is subject to two resistances, one part is the frictional resistance and local resistance encountered when the gas passes through the various systems of the kiln, which is caused by the structure of the kiln and cannot be artificially Only when the airflow speed changes, it increases or decreases in a certain proportion. On the other hand, the airflow also encounters the resistance of the blank stack, which can be changed. By changing the stacking method, the blank stack can be changed to help the air flow. Thereby changing the ventilation in the kiln and improving the firing conditions.
Generally speaking, reducing the resistance can increase the air volume. In the process of changing the density of the billet, the wind speed and air volume in the kiln are actually changed, and the combustion conditions of the fuel in the kiln are changed. Where the density of the billet is low, the resistance is small and the ventilation volume is large; the wind speed is high, and the fuel combustion conditions Well, the heat transfer coefficient is large, which is conducive to the sintering process. Therefore, the quality of the stacking form, the density of the stack, and the quality of the stacking operation not only directly affect the output of the kiln, the quality of the firing quality, but more importantly, it affects the amount of fuel energy consumption, The level of burning energy consumption.
So, how to determine the method of stacking blanks? No matter what form of blank stacking is used, within a certain "degree", it is a principle that must adhere to "thin code". In addition, according to the external combustion brick or the internal combustion brick, different blanking methods are applied.
For the density distribution of the kiln section, if it is an outer fuel brick, the method of "upper density and lower density", "medium density, inner density, outer thinness", "horizontal density and smoothness" should be adopted. The curved kiln should be "dense inside and thin outside". If it is an internal combustion brick, the code method of "upper density and lower dilution" and "edge density and medium dilution" should be adopted. In the process of stacking the billets, the billet stacks at the outer chimneys should be "pulled" to ensure smooth airflow during the firing process, so that the airflow can flow evenly on the kiln section.
4. Adopt a reasonable operation method
The operation of kiln firing is multi-faceted and all-round. Only when all aspects are dealt with seriously and reasonably can the purpose of reducing the energy consumption of firing be achieved.
First of all, it is necessary to strictly control the residual moisture content of the dry billet entering the kiln, reduce the heat energy consumed by removing the moisture, lift the heating rate, and reduce the energy consumption in the preheating stage.
Secondly, it is necessary to control the length of each belt and the stability of each belt during firing, so that the length of each belt cannot be unstable, suddenly long and short, or each belt cannot be fixed in its required position, resulting in "" Drift" phenomenon, which also consumes a lot of firing energy.
Third, rationally use the air gate on the kiln and try to use the waste heat on the kiln. The higher the utilization rate of the waste heat, the lower the energy consumption of the kiln firing.
Fourth, strengthen the inspection of the sealing performance of the kiln body, so that the hot gas in the kiln is not allowed to go out of the kiln, and the cold air outside the kiln is not allowed to enter the kiln. Because whether it is the leakage of hot gas or the immersion of cold air, it is a loss of heat energy of the kiln, which will increase the energy consumption of the kiln for firing, but will not reduce its energy consumption.
Fifth, speed up the cycle times of the kiln, reduce the heat storage loss of the kiln body and the kiln car, so that the originally stored thermal energy can be fully utilized, thus reducing the energy consumption during the firing process. Sixth, improving the firing yield is the most direct and effective way to reduce the energy consumption of kiln firing. After increasing the firing yield, it can not only save a lot of heat energy, but also save a lot of energy. Electric energy and labor wages and raw material costs, while extending the service life of the equipment.