Thermodynamic Properties Investigation of Process Volatile Organic Compounds (VOCs) and Its Transport Impact Factor in Oil Sands Management

Jing Yuan,Yuyong Sun,Qianfeng Zhang,Yong Jia

doi:10.3390/nano11030709

Abstract

This paper presents a new approach for the determination of volatile organic compounds (VOCs) characteristics and their migration influencing factors in oil sands management processes and reveals the relationship between different asphaltene content and different solvents. Specifically, thermodynamic (i.e., partitioning coefficients, Kr, specific retention volume, Vg, the activity coefficients, γ and enthalpy of solution, ΔH0) and their impact factors are discussed. Gas-liquid chromatography (GLC) experimental measurements were used as the test data. A range of solvents (nC5, iC5, nC6, nC7, and Toluene) has been tested in different asphalt contents (0, 2.56, 9.93, 36.86, 53.67 wt%). There are temperatures in the range of 333.2–393.2 K (with 10 K increase) were conducted, respectively. The dynamics properties of asphalt mixture are calculated, and the relation between dynamics properties of asphalt mixture and absolute temperature, asphalt content and solvent type is discussed. The results show that within the acceptable error range, partitioning coefficients, Kr, specific retention volume, Vg, and enthalpy of solution, ΔH0 and other thermodynamic properties have a good tendency to predict, they decrease with the increase in asphaltene content and temperature and increase with the increase in solute carbon number.

Highlights

During froth treatment and water management processes, oil sands operators try their best to recover as much solvent as possible from the wastewater, but a significant amount of light solvent remains are discharged into the environment
The results of the measurements of partition coefficient Kr and infinite dilution activity coefficient γ have been used for thermodynamic calculations of enthalpy of solution ∆H0 according to Equation (6)
Those thermodynamic properties especially partitioning coefficient Kr, and activity coefficient γ of the same hydrocarbons in bitumen were discussed in detail

Summary

Introduction

During froth treatment and water management processes, oil sands operators try their best to recover as much solvent as possible from the wastewater (i.e., tailings), but a significant amount of light solvent remains are discharged into the environment. Asphaltenes in the form of asphalt or bitumen products are the most valuable component of crude oil, and asphaltene is considered to be the “heaviest component of petroleum asphalt, insoluble in n-alkanes such as pentane and n-heptane, but soluble in aromatic hydrocarbons such as toluene or xylene.” [6]. Asphaltene has complex and highly dispersed components that can form clusters in the nanometer length scale, often defined as “nanoaggregates” [9,10,11,12].

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