Article pubs.acs.org/jced
Phase Behavior and Thermophysical Properties of Peace River Bitumen + Propane Mixtures from 303 K to 393 K Yoann Dini, Mildred Becerra, and John M. Shaw* Department of Chemical and Materials Engineering, University of Alberta, 12-360 Donadeo Innovation Centre for Engineering, Edmonton, Alberta T6G 1H9, Canada S Supporting Information *
ABSTRACT: Propane and mixtures including propane as a principal component are among the leading potential candidates for co-injection along with steam for improving the process and environmental efficiency of oil sands bitumen production processes. Phase diagrams and thermophysical property data enable technologies for the development and optimization of such processes. In this work, phase behavior, phase composition, and phase densities of propane + Peace River bitumen mixtures are reported in the temperature range 303 to 393 K at pressures ranging from 1 to 6 MPa. The phase behavior of this pseudobinary mixture can be categorized as Type III according to the van Konynenburg−Scott nomenclature. Pressure−temperature at fixed composition, and pressure−composition at fixed temperature phase diagrams, and pressure−temperature phase projections are presented, along with saturated compositions and densities of the coexisting bitumen-saturated propane liquid (L1) and propanesaturated bitumen liquid (L2) phases. Saturated L1 and L2 phases are both significantly less dense than liquid water phases at the same temperatures and pressures, and the volumes of mixing, particularly for the L1 phase, are large and negative. This data set provides a benchmark for process development and process design calculations for ongoing bitumen production and deasphalting applications.
1. INTRODUCTION In situ production technologies for unconventional oils such as Athabasca bitumen are based on the steam-assisted gravity drainage (SAGD) process developed by Butler and co-workers during the 1970s.1,2 In this process, steam is injected into a reservoir through an upper horizontal injection well. Upon heating, the viscosity of the bitumen decreases by orders of magnitude3 and it flows downward by gravity to a lower horizontal production well. Bitumen remains denser than liquid water.4 A lot of energy is used to heat the reservoir. This process has high CO2 emissions, and the bitumen recovery is variable and low at less than 50%.5 Consequently, there are significant economic and environmental drivers to improve this process. One of the ways to improve this technology is to add a low molar mass n-alkane along with less and lower pressure steam. The expanding solvent-SAGD (ES-SAGD) process is one such example.6,7 However, care must be taken to ensure that bitumen + solvent mixtures remain denser than water under production conditions,4 and to ensure that the hydrocarbon-rich fluid remains in a single phase. Asymmetric mixtures, comprising low molar mass and high molar mass species, or where specie polarities differ significantly split into more than one liquid phase.8,9 For solvent-added processes to be successful, a detailed understanding of the phase behavior of and saturated phase densities of the mixtures is required over the range of subsurface and surface facility conditions envisioned. Solvent losses, including permanent loss arising from sorption on clays in the reservoir,10 must also be understood. Other related applications © XXXX American Chemical Society
of low molar mass alkanes include dilution of bitumen or partially processed bitumen,11 so that pipeline specifications for density (
