Pit furnaces for ingot heating

Whereas pit furnaces have traditionally been heated using open-flame gas- or oil-fired heaters, the ingot heating process stands to benefit substantially from making the switch to electric. So says Krister Wickman, Global Product Manager High Temperature Tubes, Tubothal® and Bayonet Heating Elements at Kanthal.

With all the efforts underway to reduce emissions of carbon dioxide and other greenhouse gases, we’ve seen increased demand for conversions and revamps of furnace heating systems from gas to electric

“With all the efforts underway to reduce emissions of carbon dioxide and other greenhouse gases, we’ve seen increased demand for conversions and revamps of furnace heating systems from gas to electric,” he says. Aside from producers of steel and other high-strength metals looking to retrofit existing systems, he says, potential customers also include OEMs that produce new furnaces.

As climate awareness becomes the new normal, electric solutions are hotter than ever. Kanthal’s electric resistance elements leave no carbon footprint, provided the electricity they use is generated from clean, renewable energy. Even when the electricity source is a fossil-based power plant, an electric heating system delivers considerably better overall resource efficiency.

90 PERCENT EFFICIENCY

Moreover, when used in a furnace, energy losses from electric elements are extremely low. Delivering efficiency levels of more than 90 percent, electric heating systems can reduce the energy use of a pit furnace by up to 70 percent.

“Whereas gas or oil-fired furnaces release a lot of energy through the stack, an electrically fired furnace is more of a closed system in which most of the heat generated stays inside the furnace,” says Wickman, who is quick to dispel the widely held misconception that electric heaters are not equipped to deliver the highest temperatures.

“With our wide range of products and heating elements – ranging from metallic elements to Globar® (siliconcarbide) and Kanthal® Super (molybdenum disilicide) elements – Kanthal can deliver energy-efficient heating solutions for furnace temperatures up to 1,500 degrees Celsius (2,730 degrees Fahrenheit),” he adds.

QUIETER AND CLEANER

Krister Wickman, Global Product Manager High Temperature Tubes, Tubothal® and Bayonet Heating Elements at Kanthal.Energy efficiency is by no means the only reason to make the switch to electric. Electric heaters do not emit any excess heat, harmful nitrous oxide or poisonous carbon monoxide, making them safer for operators. While gas burners tend to be both noisy and polluting, Kanthal’s electric solutions are quieter and cleaner than any gas- or oil-driven alternative.

Wickman explains that another drawback of open-flame-fired furnaces is non-uniform furnace temperatures creating potentially damaging local hot spots.

“Whereas gas flames are extremely hot at the point of maximum combustion, the surrounding space is significantly cooler. On the other hand, electric heaters ensure temperature uniformity and even heat distribution throughout,” says Wickman. “This creates a reliable, repeatable heating process that enhances the overall quality of the end product, regardless of the temperature requirement.”