Wood Residues as Fuel Source for Lime Kilns

Abstract

One of the main obstacles to total energy self sufficiency of kraft mills appears to be the fossil fuel requirements of the lime kilns. If an economical technology can be developed which allows fossil fuel to be replaced in whole or in part by wood-based fuel, the savings in fossil fuel by the pulp and paper industry would be very substantial. Our study focuses around the direct in-situ combustion of hog fuel fed from the cold feed end in order to substantially reduce the fossil fuel fired from the hot product discharge end of the lime kiln. Thus far we have carried out two series of tests using two different pilot-scale kilns and dry limestone in the first test series and mill produced lime mud in the second test series. Mill scale trials have just been completed and the preliminary results indicate that our approach is potentially a very cost-effective and simple option to substantially reduce or possibly eliminate fossil-fuel usage in lime kilns.