Substitution of oil by hogged fuel in a kraft process lime sludge kiln

Hogged fuel, typically at 55% moisture content, was combusted in a wet-cell burner and the flue gases applied to a lime sludge kiln. Up to 78% oil substitution was achieved, consistent with satisfactory lime quality and availability. Specific energy consumption was high because heat transfer was less efficient. Computer simulation techniques were used to develop parameter profiles throughout the kiln and to predict optimal performance. Optimized kiln conversion was shown to be economically advantageous if hogged fuel is available for $7.00 per cubic meter or less, assuming an oil price of $30/bbl ($0.189/l).