Reduction of TRS Emissions from Lime Kilns

The pulp and paper industry has been struggling to meet the new and stringent TRS (Total Reduced Sulphur) emission compliance standards established in recent years. However, a new approach by some regulatory bodies gives intricate operational parameters a new and important role in achieving environmental compliance. TRS compounds that cause the distinctive pulp mill odour, originate from sodium sulphide in white liquor used in the kraft pulping process. Up to 20% of TRS emissions could originate from the lime kiln and lime mud solids content is one of the operational parameters that could help reduce the TRS emissions from the lime kiln. Residual sodium sulphide in the lime mud that results in TRS gases, is dissolved in the moisture content of the mud. Although efficient lime mud washing can remove most of the residual sodium sulphide, the remaining moisture content of the mud still contains some sodium sulphide. Therefore, improved lime mud dewatering can be effective in reducing the TRS emissions from the lime kiln. Data presented in this study confirms that as the lime mud solids content increases, TRS emissions from the lime kiln decrease. Data analysis demonstrates a negative linear correlation at 5% significance level between TRS emissions and lime mud solids.MAS