26 posts
Firing locations
Can anyone please tell me what are the firing locations for coal , gas and oil firing in calciner. and degree of calcination at each stage of PH
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324 posts
Re: Firing locations
There can be multiple firing locations for all these fuels in a calciner It depends on the design of the calciner.
Calcination should only occur in the bottom two stages of the preheater. However, the preheater cyclones do not have 100% collection efficiency so some calciner material migrates upthe preheater. How much depends on the efficiency of each preheater cyclone stage, but 1% in the top stage, 5% in the second stage, 15% in the third stage, 30% in the fourth stage and then 95% in the fifth stage after the calciner would not be unusual.
Dr Michael Clark
26 posts
324 posts
Re: Firing locations
For a low NOx calciner you must fire in two points, below the tertiary air intake to create an oxygen starved "reducing zone", then above the tertiary air intake to fully combust the fuel. The reducing zone degrades the NOx generated in the main burner and burning zone of the kiln. This only works with an in-line calciner.