Case Strory LadleHeatingSystem 6 (1) (PDF)

Emergency
Number

Safety first!
“We strongly believe that all accidents
can be prevented. We continuously
strive for zero accidents – and take
personal responsibility for safety,
because we care.”
Petra Einarsson
President, Sandvik Materials Technology

Emergency
Exit

Protective
Equipment

Alarm

Assembly
Point

1

Sandvik Materials Technology │ Welding

Electrical ladle
pre-heating
Case study

Existing gas burner
system
In aluminum foundry

•

From room temperature to 850°C
in one hour
(Retained three hours – 4 hours in total for preheating)

•

Gas type: 13A (City gas)
Power: 41.7 MJ/m3

•

Average gas consumption 6 m3/h
(24 Nm / 4 hours)

3

Sandvik Materials Technology

System

Electrical ladle
heating system

4

•

Heating elements made of Kanthal® Super
RA (12/24) with 3D configuration

•

Heater unit is automatically raised and
lowered hydraulically

•

Heater specification 54kW/600A

•

Attachments on both sides to minimize
heat loss from the spouts

Sandvik Materials Technology

Heater unit

When preheating

Visual comparison
Gas burner system vs
electrical heating system

5

•

There is a small gap between the
gas burner and the ladle for
exhaust gas, whereas there is no
clear gap on the electrical heater

•

The electrical heating system is
equipped with a shielding cover for
safety. When the heater unit is
lifted, residual radiation could harm
an operator

Sandvik Materials Technology

Gas burner system

Electrical Heating system

Comparison
With gas burner system

6

•

Target temperature is fixed to achieve the same
temperature in the outer wall, then a comparison is
made in power consumption between the electrical
heating system and the gas burner system

•

Both primary and secondary electricity consumption
are measured (to include power loss in controller,
cable, etc)

•

Target temperature: 920

•

Temperature monitoring is always active (by
Programmable Logic Controller, PLC) and
controlling upper limit

Sandvik Materials Technology

(thermocouple)

Temperature measurements
In aluminum foundry

•

There are thermocouples at 7 points
on the heater to measure temperature
when preheating

•

A data logger records each
temperature every 30 seconds

•

Thermocouple number 7 measures
the temperature of the exhaust gas
2
6

7

Sandvik Materials Technology

Outer shell temperature comparison
After 4 hours of preheating
Gas burner system

•

8

Electrical heating system

Due to variations in the image resolution it appears that there are temperature differences on the electrical heating system. However,
each point measured showed almost the same temperature.

Sandvik Materials Technology

Temperature profile in outer shell
Gas burner system

After
1 hour

•

9

Electrical heating system

Same as after 2 hours, but the electrical
heating system showed slightly better
temperature uniformity

Sandvik Materials Technology

Gas burner system

After
2 hours

•
•

Electrical heating system

Showed almost same temperature profile
But, only upper part for burner system showed
higher temperature

Gas burner system

After
4 hours

•

Electrical heating system

The burner quickly heats the upper area due to
the effect of the exhaust gas.