IMPROVED ENERGY EFFICIENCY, SAFETY, AND EMISSIONS IN SMELT DISSOLVINGTHROUGH SMELT SOLIDIFICATION

Solidification of kraft smelt prior to dissolving to make green liquor represents a modification of the conventional recovery process that c an improve energy efficiency, while eliminating the potential for smel t-water explosions in the dissolving tank and reducing TRS emission le vels in the dissolving tank vent stack. Use of a steam-fluidized bed c oncept may provide an economic means for achieving these benefits. Tec hnical issues have been identified for this proposed process modificat ion, and results of preliminary laboratory experiments are presented w hich address several of these issues, while showing additional process benefits in decreased dregs flow and enhanced dregs settling rates in the green liquor clarifier. Several unanswered process concerns still remain, including ultimate use of the superheated steam product and d isposition of smelt sulfur. Research is planned to address these issue s.