THE USE OF POLAR ORGANIC SOLVENTS TO CONTROL SULFUR DIOXIDE EMISSIONS: A STUDY OF SOLUBILITIES AND CONCEPTUAL DESIGNS (VAPOR PRESSURES, DESULFURIZATION)

The purpose of this study is to investigate the use of polar organic solvents to absorb SO(,2) from dilute gas streams. Activity coefficients of SO(,2) in polar organic solvents were determined from experimental solubility data and from predictions based on basicity scales and the UNIFAC method.;The data were correlated using six different phase-equilibria models: UNIQUAC, NRTL, Wilson, Van Laar, Margules, and Henry's law. The UNIQUAC model correlates the partial pressure of SO(,2) over the entire concentration range with an average absolute deviation of 5% or less, which is slightly better than the NRTL or Wilson models. In the dilute region Henry's law provides the most accurate correlation to the experimental partial pressure data with an average absolute deviation of 4% or less.;Sulfur dioxide activity coefficients at infinite dilution and at 25(DEGREES)C were predicted using several basicity scales. The Gutmann donor number and Arnett basicity scales predict SO(,2) activity coefficients to within (+OR-)30 to 50% of the experimental values obtained in this study and from the literature. The UNIFAC method for predicting activity coefficients from VLE data on the molecular groups is accurate to within 20%.;Process designs were evaluated for controlling SO(,2) emissions from sulfuric acid plants and for flue gas desulfurization (FGD) of electric utilities. Although a sulfuric acid plant using an organic-absorption/SO(,2)-recovery process has no capital cost savings over the conventional double-contact/double-absorption process, operating costs are about 15% lower. An organic-absorption/sulfur-recovery (OA/SR) process for FGD, which produces a sulfur by-product, was compared with 14 FGD technologies previously evaluated in the literature. Compared with other regenerable FGD technologies such as the Wellman-Lord, the capital and operating costs are substantially lower (35% or more). (Abstract shortened with permission of author.);Vapor-liquid equilibrium (VLE) data for SO(,2) in eight polar organic solvents and three mixtures of organic solvents were investigated over the temperature range of 30 to 95(DEGREES)C and over a concentration range of 0.02 to 0.16 weight fraction of SO(,2).