Study of the thermo-physical properties of bitumen in hydrocarbon condensates

Abstract

The reduction of viscosity with inappropriate diluents could lead to asphaltene precipitation. To use condensates effectively however, their effects on asphaltene precipitation and deposition must be well examined. In this study, the influence of inter-particle interactions of asphaltene on the viscosity and heat of mixing in solutions of bitumen-condensate mixtures are compared to those of bitumen in aromatic solvents and in condensate-toluene mixtures. Three bitumen, two heavy oils, and five condensates from different reservoirs were examined. The results indicate that the presence of aromatic solvent in bitumen delays the on-set of asphaltene precipitation due to the presence of dipole-dipole interactions as well as hetero-molecular interactions. In pure condensates, strong hydrogen bonding and moderate homo-molecular interactions are predominant and, therefore, result in reduced asphaltene precipitation and low enthalpy of mixing. The on-set of asphaltene precipitation in bitumen and heavy oils is delayed in the presence of aromatic solvents, decreasing with reduction in the composition of aromatic solvent in the condensates.

Study of the influence of asphaltenes on modeling of viscosity of Nigerian crude mixtures

“…As expected, the results clearly show that the presence of asphaltenes, even in a small amount, in crude oil has a significant impact on the viscosity of the oil. The results are consistent with those obtained in our previous work with calorimetric method [8]. Viscosity-temperature relationship for Warri light crude oil with different wt% Plover Lake bitumen.…”

“…The mixture was agitated using a G10 gyrotary shaker for 24 hours, left to stand for two hours and filtered using a 7.0cm whatman filter paper as described in ASTM 863-63. The procedure used to recover the deasphalted bitumen has been documented in our previous publication [8]. To prepare the mixtures of light crude oil containing 5wt% to 40wt% bitumen, a known amount of the bitumen was added quantitatively to the light crude oil in increment of 5wt%.…”

Stochastic simulation of cavitation bubbles formation in the axial valve separator influenced by degree of opening

“…The diameter of the throttle holes of the separator corresponds to the value d 0 =3,5×10 4 m. The relative calculation error was 13%. The deviation of the theoretical curve from the experimental values for the last rows of the throttle holes is explained by the limitation of the model's application area for the initial stage of hydrodynamic cavitation, when Re=(1,5-10,0)×10 4 . The proposed stochastic model does not take into account such consequences of the evolution of cavitation bubbles as possible splicing of bubbles, growth of their size, collapse, etc.…”

“…Comparison of theoretical results according to expression (12) and experimental data obtained on a pilot plant by Lebedev et al 28 is shown in Figure 2. The analysis was performed with the degree of valve opening ζ=0,6, when the values of the model parameters are equal to: E 0 = 1,97×10 -8 J; M = 2,01×10 -12 kg×m 2 /c; Re y =9,8×10 4 . The diameter of the throttle holes of the separator corresponds to the value d 0 =3,5×10 4 m. The relative calculation error was 13%.…”

“…1,2 Cavitation shows a preferred character when cleaning the working surfaces of pipes from sediment, measures to reduce the viscosity of working fluids, for example, oil products, etc. 3,4 Successful solution of problems of designing effective regulatory equipment for pipeline systems is associated with the accounting for cavitation. In particular, hydrodynamic cavitation is usually observed in the flow part of the valves in bubble form.…”