Ladle Heater Marketing Case Story PDF 111413 (PDF)

An electric heater will cut energy costs
– but do the benefits end there?
Case story · LOWER ENERGY CONSUMPTION AND REDUCED EMISSIONS
WITH A KANTHAL® ELECTRICAL LADLE HEATING SYSTEM
A large automotive company in Japan using a gas burner ladle preheating system in its aluminum foundry made the decision
to install a Kanthal electrical heating system. Comparison tests performed by Sandvik on the two systems showed that the
electrical system is much more efficient, offering significant advantages for the automaker. Benefits include a 50% reduction
in energy consumption, less environmental impact, and higher molten metal quality. The system also has a positive effect on
operator health and safety.

The challenge

The Sandvik solution

The existing gas burner preheating system in the company’s
foundry, operating on city gas type 13A, provided 41.7 MJ/m3
with an average gas consumption of 6 m3/h. The target temperature was 920°C. The system raised the ladle temperature from
room temperature to 850°C in 1 hour and total preheating time
was 4 hours. The company wanted to reduce preheating times,
energy costs and emissions.

Sandvik recommended a Kanthal electrical ladle heating system,
specification 54kW/600A, and performed a detailed analysis
of the improvement in efficiency compared to the gas burner
system.
In Kanthal electrical heaters the heating elements are made of
Kanthal Super RA(12/24) with 3D configuration. The elements
are mounted in a reflector arrangement that allows the radiation to be more accurately directed towards the target area. The
heater is automatically raised and lowered hydraulically, and
there are attachments on both sides to minimize heat loss from
the spouts. A timer system starts preheating automatically at a
preset time, and heating is monitored and controlled by PLC.
To evaluate the efficiency of the system compared to the gas
burner system, Sandvik equipped the heater with thermocouples
to measure the temperature at seven different points on the ladle
during preheating. A data logger recorded the temperature at
each point every 30 seconds. The temperature of the exhaust gas
was also measured.

Kanthal ladle dryers and ladle heaters (pre-heaters) are available
for ladles with inner diameter 500–2100 mm (20–83 in.), and
installation is usually very simple.

The result
50% reduction in energy consumption, preheating time
50 minutes
In terms of economy, the Kanthal electrical ladle heating system
is a major improvement on the gas burner system. The net energy
efficiency of the Kanthal heater is approximately 70%, compared to about 25% for a typical gas solution. In this specific
case the energy savings were 50%, with the potential to increase
to 85%, depending on the conditions.
The total energy consumption of the Kanthal heater is 131 kWh,
which is about half the consumption of the gas burner solution,
and the system raises the ladle temperature to 920°C in 50 minutes. Final power is 19.2 kW (heat loss by radiation at almost
steady condition).

Simpler to operate, no risk of explosions
The electrical heater is simpler to operate. With a gas-fired solution, it is necessary to turn on gas valves and continuously check
that there is a flame in order to avoid leaking combustible gases
into the factory with the accompanying explosion risk.
With electrical heating the heater can be turned on at the touch
of a button. The temperature is monitored to make sure it’s in
the target area for the specific product or process. The product
quality is higher since there is no risk of any combustibles diffusing into the molten metal and potentially altering the chemical
composition. The timer system will start preheating without
operator involvement and this also reduces labor costs.
Clean and quiet, no harmful gases

The uniform temperature profile achieved when using electrical
elements to heat the ladle, and the fact that there is no flame or
streaming hot exhausts, will prolong the lifetime of the refractory
by 10–15%.
CO2 emissions 0.2–0.3 kg/kWh, zero NOx
There are significant environmental benefits since emissions
of greenhouse gases are reduced. CO2 emissions for the Kanthal
electrical heater are 0.2–0.3 kg/kWh, with zero NOx. CO2
emissions for gas burners of this type are around 10–12% of
the exhaust volume during combustion. NOx emissions for gas
burners can be in the range 500–1000 ppm. In addition,
electrical heating does not create any CO (carbon monoxide),
whereas with gas-fired solutions CO can form during
combustion.

The Kanthal electrical heater benefits employee health and
safety by being safe, clean and quiet in operation, and emitting
no harmful gases. During the drying operation additional fine
tuning is possible, lowering the risk of bubbles in the refractory.
There is also no risk of water vapor in the vessel thus minimizing any risk of a vapor explosion. Lastly there is, of course, no
gas pipeline required.
The electrical heater is also more versatile than gas-fired solutions. It is not only limited to preheating, but can also be applied
to drying and firing, simply by changing the program in the
control system.

Sandvik Group

The Sandvik Group is a global high technology enterprise with 47,000 employees in 130 countries. Sandvik’s
operations are concentrated on three core businesses: Sandvik Tooling, Sandvik Mining and Construction and
Sandvik Materials Technology – areas in which the group holds leading global positions in selected niches.
Sandvik Materials Technology

Kanthal is a Sandvik owned brand, under which world class heating technology products and solutions are offered.
Sandvik, Kanthal, Superthal and Fibrothal are trademarks owned by Sandvik Intellectual Property AB.

Challenge
   your expectations
Sandvik Materials Technology
Sandvik Heating Technology AB · Box 502 · 734 27 Hallstahammar, Sweden
Phone +46 220 210 00 · Fax +46 220 211 66
www.kanthal.com · www.smt.sandvik.com

S-KA073-SS-ENG, 11.2013. Printed in Sweden

Sandvik Materials Technology is a world-leading manufacturer of high value-added products in advanced stainless
steels and special alloys, and of medical implants, steel belt-based systems and industrial heating solutions.