Furnace Technology
The reason for excessive clinker formation in gas producers is the

Use of fuel having too low an ash fusion temperature
All of these
Use of coal/coke containing a high % of fines and ash
Development of hot spots in the fuel bed and an abnormally high rate of gasification

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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.
Should be as low as possible i.e., 1 : 2
Is the ratio of maximum to minimum permissible heat input rates

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