Application of the hottest Pyronics burner in alum

2022-08-07
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Application of Pyronics burner in aluminum industry

about 25 years ago, Pyronics company created a new technology, which focuses on using the high-speed flue gas generated in the high-speed burner in various aluminum melting furnaces and processing industrial furnaces. Before that, the main heat transfer mode in the heating process of aluminum industry was high-temperature radiation heat transfer. In addition, due to technical limitations, in order to ensure complete combustion, 25-30% excess air must be ensured when burning oil. Because the excess air share is too high, the flame of the burner has to avoid the molten aluminum to avoid too much dross in the furnace, otherwise it will cause incomplete combustion due to excessive fuel input, and the flame often rushes out from the exhaust flue and the sealing ring on the door. In the 1970s and early 1980s, Pyronics developed a new type of nozzle mixing burner, which has the characteristics of low excess air share and high outlet flue gas velocity. This burner is used in aluminum melting furnace to enhance convective heat transfer during melting process. Pyronics was the first company to introduce this technology into the aluminum industry. Since then, this technology has become the standard technology for high-efficiency aluminum melting. After hundreds of industrial furnaces have been transformed or this new technology has been adopted, remarkable results have been achieved and fuel consumption has been reduced. The railway system is also anxious about 15-20%

the working mechanism of this technology is briefly introduced below:

convective heat transfer

characteristics of aluminum aluminum has a very high thermal conductivity, About 4 of steel "Polyurethane adhesive is mainly used for windshield, lamp, filter element, interior ceiling, etc. in automobiles. At the same time, the specific heat of aluminum is about twice that of steel, while the radiation coefficient is only 1/2 of that of steel. Due to its good thermal conductivity, cold aluminum can quickly absorb heat. A low radiation coefficient means that its ability to reflect radiant energy is twice that of steel. At the same time, a high specific heat means that in order to reach the same temperature, the Aluminum per unit mass must absorb twice as much heat as steel per unit mass. The thermal conductivity of molten aluminum is relatively low

when the aluminum melt is in an environment with an ambient temperature of more than 760 ℃ and full of oxygen and carbon dioxide, it is very easy to generate alumina and scum. Similarly, in the environment full of water vapor, the generation of scum will also be accelerated: (3H2O + 2Al = Al2O3 + 3h2). At high temperature, the newly separated free hydrogen is more likely to enter the aluminum melt

combustion products in industrial furnaces

with the help of these UD belts

after the mixed combustion of gas and 10% excess air, the composition of flue gas in the furnace is: 75% nitrogen, 11% water, 12% carbon dioxide and 2% oxygen. Except that the burned out carbon in the flame has a high radiation coefficient, only water vapor and carbon dioxide in the combustion products have a certain radiation capacity. The radiation capacity of other components is very weak. However, the heat contained in nitrogen accounts for the largest share of the total heat contained in flue gas after repeated cycles, about 70%

generally speaking, the volume of nitrogen accounts for about 75% of the total volume of flue gas, and the calorific value accounts for 70% of the total calorific value of flue gas. It has no contribution in industrial furnaces whose working mode is mainly radiation heat transfer. Therefore, if convection heat transfer is applied in aluminum melting furnace, the heat contained in nitrogen can be effectively applied

prronics burner series introduction

first, we need to understand several terms. Among the burners, there are two concepts of high speed. The first one refers to that the combustion products from the burners have a very high speed, up to 125m/s. these are usually burners with small power, such as HS and HMB series of Pyronics company, whose power can reach 1200kW. The second high-speed concept refers to high-power burners with power ranging from 1000kW to 7000kw. The outlet speed of such burners is about 85m/s. Nm and XDF series of Pyronics belong to this kind of burners. Except that nm series must burn gas, XDF and HFDF can burn light diesel or gas according to user conditions. The practice in the past 20 years has proved that these burners can effectively improve the overall convective heat transfer effect in aluminum furnaces. The above burners can operate under the condition of low share of excess air, and the outlet flame is also short. In this way, the cold workpiece can be directly put into the furnace without generating a large amount of scum

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