Furnace Technology
Ceramic coating material for furnace refractory, which increases its emissivity and thus the radiation heat transfer rate in the furnace, comprises of

Zircon powder
Beryllium
Thoria
Graphite powder

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Furnace Technology
Turn down ratio of a burner

Is normally much more for a continuous furnace as compared to a batch furnace
Should be 1:1 for a batch type furnace.
Is the ratio of maximum to minimum permissible heat input rates
Should be as low as possible i.e., 1 : 2

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