Strategies for Operations of Vertical Shaft Kilns
P. C. Okonkwo, S.S Adefila

Abstract
Vertical shaft kilns have among others the advantage of low investment profile and hence very suitable for small and medium scale processing of various solid minerals such as limestone. The low investment profile therefore makes it attractive in developing countries where sources of investment capital are lean. Vertical kilns however are plagued with a number of operational problems such as channeling, stratification, hanging accident, poor heat distribution among others. This work investigated the effects of burner types, firing rate and degree of draft on the vertical kiln temperature profile and hence the efficiency of the kiln. A pilot twin shaft lime kiln of 1.5 ton per day capacity was employed in the evaluation. It was shown that low firing rates of the burners affects negatively the kiln throughput and very low drafts lead to excessive backfiring of the burners. Many strategies were proposed to mitigate various negative phenomena experienced in the operations of vertical kilns.

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