The holding and mixer furnace is where molten aluminum is alloyed with additional elements, such as copper, magnesium and silicon, in order to give the final product its distinct properties before it’s cast into sows or ingots. As such, temperature controllability and uniformity are essential.
Gas burners are the most common heating solution, however as there is no heat recuperation, the thermal efficiency is typically only around 30-40 percent. They can also have an adverse effect on productivity and yield.
“Because the gas burners are often blowing directly onto the bed of aluminum, this causes it to react with oxygen and produce a lot of aluminum oxide,” says Daniel Burton, Business Development Manager, Kanthal. “This is essentially wasted material, and in some cases, it can amount to around one million dollars per year.”
Instant energy and cost savings with electric heating
The high temperature uniformity and precise temperature control offered by Kanthal’s Tubothal® heating elements make them ideal for holding and mixer furnaces. And because there is no heat loss through exhaust gasses, the thermal efficiency is around 98 percent. Furthermore, because it is a radiant solution that does not mix oxygen with the aluminum, it does not increase dross production and the resultant wastage of material.
By switching from gas heating to electric, you can reduce energy consumption by around 60 percent. The payback from investing in electric heating is substantial.
“By switching from gas heating to electric, you can reduce energy consumption by around 60 percent,” says Daniel. “This alone is a significant saving, but when you also factor in the reduction of wasted metal from dross production, the payback from investing in electric heating is substantial.”
A cleaner, safer process
As with all electric heating solutions, Tubothal® heating elements offer the benefits of zero exhaust emissions, which drastically improves the environmental footprint. Along with minimal noise levels, it also creates a safer and more pleasant working environment. Workplace safety is further improved by the fact that electric heating does not produce water vapor, and therefore eliminates the risk of explosions caused by molten aluminum coming into contact with moisture.
In addition, Tubothal® heating elements are easy to install and can be replaced even when the furnace is operating at high temperatures. This means that in the event of a breakdown, repairs can be made with the minimum of downtime.
Four benefits to using Tubothal® heating elements in holding and mixing furnaces
- Better thermal efficiency. The thermal efficiency of gas burners is around 25-40 percent, whereas with electric heating it can be as high as 95 percent. This translates into a reduction in energy consumption of around 60 percent.
- Less wasted metal. Since Tubothal® does not mix oxygen with the aluminum, it does not cause dross or the resulting wasted material.
- Less downtime. Tubothal® elements are easy to install and remove, enabling repairs to be done with minimum downtime.
- No exhaust emissions. This not only reduces a plant’s carbon footprint but also contributes to a cleaner, quieter and safer work environment.
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