Solubility of sulfur dioxide in a commercial hydrocarbon mixture in the temperature range of (303 to 343) K: Effect of hydrocarbon composition on absorption

The sulfur dioxide solubility in hydrocarbon mixtures mostly depends on the chemical composition of the solvent. The changes in noncyclic-cyclic and saturated-unsaturated parts affect not only the physical properties of the liquid but also the gas solubility. This work evaluates the solubility and average enthalpy of dissolution of sulfur dioxide in a commercial hydrocarbon mixture (heat transfer oil) in the temperature range of (303 to 343) K and at gas loading pressures below 250 kPa. The investigated commercial hydrocarbon mixture mainly consists of aliphatic alkanes according to the ¹H NMR, Fourier transform infrared (FT-IR), and gas chromatography/mass spectrometry (GC-MS) analyses. Gas solubility is expressed in four different units; Henry's constant, Ostwald's coefficient, sulfur dioxide mole fraction, and grams of solute in unit volume of solvent at three different pressures including solubility-temperature relations in the working temperature range. The effect of solvent chemical composition on sulfur dioxide solubility is also discussed with respect to the previous studies on hydrocarbon mixtures. The presented solubility data provide essential knowledge for development of modified hydrocarbon mixtures with high-boiling points to create absorption solvents suitable for high flue gas temperatures based on thermally stable hydrocarbon matrices. The hydrocarbon matrices can be further improved by absorption capacity modifying agents to create novel solvent systems for cost-effective desulfurization processes.