The Worlds Largest Induction Furnace (Coreless Hydraulic Tilt type). 24.02.2016
The Worlds Largest Induction Furnace (Hydraulic Tilt Coreless type)
Built by Australians for Australians.
National Sales Manager
Inductotherm Group Australia Pty. Ltd.
for the Australian Foundry Conference,
Sydney, Australia 2005
It’s not every day that Inductotherm builds a worlds largest induction furnace, although high powered medium frequency furnaces are common place in its production programme. This summary of a paper presented at an Australian Foundry Conference describes the manufacture, assembly, transportation, installation and commissioning of the Worlds Largest Induction Furnace (Coreless Hydraulic Tilt) at 80 tonne iron capacity.
The previous worlds largest induction furnace (coreless type) was built by Inductotherm Europe for a German ship propeller manufacturer Mecklenburger Metallguss GmbH in the year 2000.
This furnace is an 80 tonne bronze capacity and is one of eight Inductotherm furnaces at the foundry. These furnaces enable them to cast the world’s largest ship propellers, with cast weights up to 180 tonnes.
This propeller shown above is 10 meters diameter and weighs 80 tonne. At time of print, this foundry has an overhead crane capacity of 320 tonne and is able to produce 100 big ship propellers per year.
The Australian built worlds largest induction furnace (80 tonne iron capacity furnace was ordered by HIsmelt (Operations) Pty. Ltd for installation at their Kwinana plant in Western Australia. This furnace, though also 80 tonne capacity is 200 mm taller to accommodate 80 tonnes of molten iron, making it the Worlds Largest Induction Furnace (Coreless Hydraulic Tilt Melting type).
Hismelt first requested a 160 tonne furnace but when told of the time required to design manufacture and deliver such a large furnace they then considered other options. We suggested to Hismelt that we could build an 80 tonne furnace with a short lead time as we could largely utilise the Inductotherm Europe 80 tonne furnace design. Very little redesign work was required and Hismelt rushed the order through insisting on a short delivery.
Apparently, Hismelt Engineers were having second thoughts about the ability of their Smelt Reduction Vessel (SRV) being able to self start. Their pilot plant SRV could self start but the new larger vessel was a different shape. For added security, they decided they needed, as they called it, a starter motor to kick start their SRV.
Hismelt required a minimum of 160 tonne molten iron liquid heel to start their SRV. This 160 tonne heel was to be produced in 24 hours. This would be possible with the use of two eighty tonne ladles. The first 80 tonne melt would be produced and raised to 1580°C. 40 tonne would be transferred to a preheated 80 tonne ladle. The furnace would then be back charged with another 40 tonne and again raised to 1580°C. 40 tonne would again be transferred to the ladle, filling it completely.
The furnace would then be back charged again with another 40 tonne charge and raised to 1480°C. and then transferred to the second preheated ladle. The two 80 tonne ladles would then be emptied into the Smelt reduction vessel.
This melting operation above would be required only once every 18 months as its only requirement is to start the SRV. The SRV has a scheduled shut down for replacement of SRV refractories once every 18 months.
To meet this requirement Inductotherm Group Australia Pty Ltd, located in Seaford Victoria, built an 80 tonne Steel Shell Hydraulic tilt furnace powered by a 5000 kW 200 Hz VIP PI Power-Melt power supply capable of melting iron at the rate of 10 tonnes per hour. Also in the scope of supply was a supply transformer, hydraulics, transport, installation and commissioning.
Because of the extra large furnaces size, many special work platforms were constructed at various stages of manufacture.
The Induction furnace was built in only 22 weeks by Inductotherm in Seaford Victoria and was shipped to HIsmelt Kwinana Plant in Western Australia by road. Dismantled for transportation, the Steel Shell body weighed 62 tonne.
When reassembled in Perth the total operating furnace weight would be in excess of 180-tonnes. The sheer physical size and weight of the furnace necessitated special cranes and handling equipment.
The furnace was designed with careful selection of refractories and insulation materials to achieve minimum hold power and minimum temperature loss. During commissioning the following heat-loss measurements were taken.
Furnace was fully molten at 1554°C power turned off and 3 hrs 11 minutes later the fu
rnace lid was raised and temperature was dipped again to show 1491°C. A drop of only 63°C. This equates to one degree loss in 3.03 minutes or 19.8 degrees per hour.
The Induction furnace superheat rate on 80 tonne molten iron at 1500 degrees was measured at 2.5°C/minute or 150°C/hour. Hold power for 80 tonne of iron at 1400°C is only 500 kWs.
From placement of order the furnace was complete and ready for shipment at week 22 and the 5000 kW power cabinet was ready for shipment at week 23.
A little about the Hismelt Process (taken from the Web in 2005).
HIsmelt is a direct iron making process – in which iron ore fines and/or other iron containing materials and ordinary steaming coals are injected directly into a molten iron bath to produce a quality molten pig iron. The new plant is designed to produce 800,000 tonnes per annum at the rate of 110 tonne per hour and has an approximate value of A$400 million.
The current HIsmelt process occurs within a vertical Smelt Reduction Vessel (SRV) under pressure. The vessel is refractory lined within the hearth and water cooled in the top-space. The refractory hearth contains the molten iron bath. A think slag layer is situated above the metal bath
Feed materials (coal, iron bearing metallic fines and fluxes) are simultaneously injected into the molten iron bath by a nitrogen carrier gas through side-mounted lances. Fluxes, mainly lime and dolomite are injected as fines.
Upon contact with the iron bath, dissolution of the carbon in the coal occurs which reacts with the oxides in the iron bearing feeds, forming carbon monoxide. Rapid heating of the coal also results in cracking of the coal volatiles releasing hydrogen.
A fountain of metal and slag erupts into the top space by the rapid exiting of the carbon monoxide, hydrogen and nitrogen carrier gas from the molten iron bath. Hot air at 1200C is blasted into the top space through a water-cooled lance. The carbon monoxide and hydrogen is post combusted with oxygen (from the hot air blast). The heated metal and slag fall back into the bath providing the energy for direct smelting of the iron ore. The fountain of metal and slag coats the water-cooled panels, which reduces energy loss. The off-gas from the process is cooled in a water-cooled hood and cleaned in a scrubber. The off-gas can be used as a fuel for hot blast stoves and other equipment such as a co-generation plant.
The Hismelt Technology product is described as a new frontier in Iron making, and is the new future of the iron and steel industry. It can be considered both as a potential replacement for the blast furnace and as a new source of low cost iron units for the Electric Arc Steel making industry.
For additional reading on the HIsmelt process, refer to Hismelt web pages.
The worlds largest induction furnace project ran like clockwork. The furnace was delivered on time according to the customer’s requirements and the furnace performed to all expectations.
This success story was due to having a network of reliable local material suppliers, overseas Inductotherm corporate support and the enthusiasm, hard work and dedication of employees at Inductotherm Pty. Ltd. and Inductotherm local Service in Western Australia.
A special thank you to everyone involved in the furnace project.
Note Year 2016: The Hismelt plant in Western Australia has been sold and the world’s largest induction furnace (hydraulic tilt type) is being re commissioned in China.
For additional details on induction furnace equipment contact the Author:
Chris Buck at Inductotherm Group Australia Pty. Ltd.