We were contracted to replace gas heating with 70 KWatt electrical heating for the curing of ceramic snorkels in the steel casting industry.
The design went through various iterations. Rugged, high-performance rod elements were chosen which could sustain extreme air temperature. Design of the air path and balancing the element surface load and airflow rate required careful attention as the elements were running at their rated limit.
Air recirculation was introduced to reduce losses. The control panel included programmable ramp-soak controllers with solidstate relays for precise control of the heating profile.
The advantage of the electrical air heater compared to the gas heater was primarily better process control. With the electrical heating system being smoother and more accurate, temperature ramps could be achieved.
The electrical system was more cost effective and a far safer solution considering the fire hazard that the gas presents.
Air Heater
Some of the typical challenges we faced:
- Achieving 800°C air temperature
Providing sufficient volume flow
Facilitating easy replacement of elements
Ensuring optimum heat transfer
Accurately controlling temperature ramps for the process
Available electric power limited to 70KWatt
- Meeting the requirement of easy access to the elements for maintenance
