Thermodynamic Behavior of Process Volatile Organic Compounds (VOCs) in Oil Sands Environment Control and Its Influence on Solution

Abstract

In this study, the thermodynamic properties of process Volatile Organic Compounds (VOCs) in asphalt (solute) are studied by experiments and models. Thermodynamic properties (partitioning coefficients, Kr, and the activity coefficients, Y, enthalpy of solution, \(\Delta \mathrm{H}_{0}\) ) of the five different solvents: nC5, iC5, nC6, nC7, and toluene under their different asphalting contents (0, 2.56, 9.93, 36.86, and 53.67) were studied. The linear relationship between absolute temperature T (333.2 K, 343.2 K, 353.2 K, 363.2 K, 373.2 K, 383.2 K, 393.2 K) and different solvents (nC5, iC5, nC6, nC7, toluene) was discussed in detail. The thermodynamic behavior between salute and solvents is one of the foundations of the modeling process, which can be interpreted from the perspective of the change of the molecular size ratio between solvents and solutes and the interaction between them. The determined partitioning and activity coefficients provide important parameters for thermodynamic modeling and solvent recovery industry. It is found that the activity coefficient decreases with the increase of asphaltene content (solute) and increases with the length of solute alkane chain (carbon number). For example, the partitioning coefficient in bitumen has 18 wt% of asphaltene(solute) are much higher than in the bitumen has 84 wt% asphaltene(solute).