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Best Suited Non-electric Heater for Galvanising

For molten bath temperatures in the range 475 degC are required. I am investigating the best suited type of heater for this duty. I suppose that electric induction heaters are a recent phenomenon; but I doubt its utility in the areas where power shut-downs are frequent. Does ruling out this option not leave behind any other option than furnace oil (dirty but potentially cheapest fuel) heaters? I look forward to hear from the experts. Thanks in advance.

Rajesh Kulkarni
Product designer - Pune, Maharashtra State, India
May 2, 2008

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May 5, 2008

The most common energy sources for galvanizing are gas (natural, LPG), oil, electric.
Electric is the least common. Natural gas (where available) is often the lowest cost per kWh, and lpg nect common where gas not available.

Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK

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May 15, 2008

Sir:
A molten zinc temperature of 475 deg C is much too hot for normal galvanizing and will quickly burn though a normal iron kettle. I believe electric induction heated cermic sheet line kettles have been around a long time in the USA. The brand name is Ajax Magnathermic. In Montreal and Quebec City there are electric induction heated general galvanizing iron kettles. In the USA there were two or three electric resistance heated iron kettles. I believe one or two of these were converted to natural gas. I worked with an electric resistance heated kettle in Johannesburg. I have seen a few kettles heated by heavy oil, especially in South America. I have been told that in China coal is used to heat some galvanizing kettles, with the coal packed against the kettle walls. Kettle life with coal is likely to be only a few months due to hot spots.
While in Ranipet (near Madras), we stopped at a gasoline station to fill up. The electricity went off and the guy had to use a hand crank to finish filling the tank. Thus you are correct that an electric kettle in India would likely not be a good idea.
Regards,

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA

Mr. Cook is right about the kettle temp., if the kettle is to be made of "kettle steel". The source of energy that I prefer is natural gas, because it is relatively clean and very easy to maintain. LPG is also a good source, and again is also easy to use with a note to be taken for safety issues due to the specific gravity (heavier than air). Since gas may not be available, oil can be used. If set up properly, oil takes more attention to keep the system running smoothly but will do you a good job.

David Jaye
Houston, Texas
May 22, 2008

Certainly I am not in favour of going in for an electric heated furnace considering the power outage what we get to see in India, but you can always think about going in for a dual fuel furnace, like lpg and diesel etc.

Ameen Syed Roohul
- Sharjah
June 1, 2008