Crude Oils Characterization of Waxes Precipitated on Cooling by DSC and Thermomicroscopy

Jean Marie, Letoffe
Pierre, Claudy
Marc, Garcin
John, Volle
Kök, Mustafa Verşan
Mixtures of 2 and 4 wt% of pure paraffins in a crude oil matrix and 14 crude oils were characterized by differential scanning calorimetry (d.s.c.) and thermomicroscopy at a cooling rate of 2 K min(-1) in the temperature range from +80 to -20 degrees C. Pour points were also determined. In the temperature range used, a constant value of 200 J kg(-1) for the enthalpy of precipitation was determined. For crude oils which contain >10 wt% of n-paraffins, the pour point is reached when similar to 2 wt% of waxes have precipitated. By thermomicroscopy, it was observed for mixtures of pure paraffins and crude oil matrix that the size of the crystals is small and depends on the length of paraffinic chains at the pour point. For crude oils, at the pour point the same final state is obtained (unlike diesel fuels). Even if the rates of precipitation are very different, the crystal size is always small (1-3 mu m). This fact suggests that each crude contains nuclei which are responsible for heterogeneous germination.


Thermal characteristics of crude oils treated with rheology modifiers
Kök, Mustafa Verşan; Cloudy, P.; Martin, D.; Garcin, M.; Volle, J.L. (1997-12-01)
Thermal characteristics of eight crude oils and their treatment with additives were studied by differential scanning calorimetry (DSC), thermomicroscopy, viscometer and pour point tester. Different additives were found as more effective for different type of crude oils depending on the wax content. Crude oils showed a reduced pour point after treatment with additives. Effects of different additives were also discussed by analysing the DSC curves and thermomicroscopy result.
Thermal characterization of crude oils by pressurized differential scanning calorimeter (PDSC)
Kök, Mustafa Verşan; Nurgaliev, Danis K. (Elsevier BV, 2019-06-01)
In this research, pressurized differential scanning calorimeter (PDSC) were used to estimate the thermal and kinetic behaviour of two different crude oils from Tatarstan oil fields under three different pressures (100, 600, 2000 kPa) at a constant heating rate (10 degrees C/min). The heat flow curves of both crude oils indicated two reaction regions known as low temperature oxidation (LTO) and high temperature oxidation (HTO). The reaction intervals were shifted to lower temperature regions with the increas...
Thermal Analysis of Crude oil lignite mixtures by Differential Scanning Calorimetry
Kök, Mustafa Verşan (Elsevier BV, 1994-04-01)
Thermal characterization of lignite, crude oils and their 10 and 20% mixtures were investigated by differential scanning calorimetry (d.s.c.). The calorific value of the lignite increased in mixtures depending on the crude oil type. In pyrolysis runs, temperature ranges where distillation and visbreaking occur were identified for the crude oils studied. The effect of heating rate was also studied, and higher reaction temperatures and higher heat flow rates were observed at d.s.c. peak thermograms with incre...
Crude oil characterization using TGA-DTA, TGA-FTIR and TGA-MS techniques
Kök, Mustafa Verşan; Nurgaliev, Danis K. (2017-06-01)
In this research, combustion characterization and kinetics of four different origin crude oil samples were determined using thermogravimetry - differential thermal analysis (TGA-DTA) and thermogravimetry - Fourier transform infrared (TGA-FTIR) and thermogravimetry mass spectrophotometry (TGA-MS) techniques.
Comparison of Wax Appearance Temperatures of Crude Oils by Differential Scanning Calorimetry, Thermomicroscopy and Viscometry
Kök, Mustafa Verşan (1996-07-01)
This paper presents the results of an experimental study of the determination of wax appearance temperatures (WAT) of 15 crude oils by differential scanning calorimetry (d.s.c.), thermomicroscopy and viscometry. Good agreement is obtained among the three techniques for crude oils having a significant precipitation rate. Considering the great diversity of crude oils, it is concluded that d.s.c. and thermomicroscopy should be used together for a better understanding of the determination of WAT of crude oils.
Citation Formats
L. Jean Marie, C. Pierre, G. Marc, V. John, and M. V. Kök, “Crude Oils Characterization of Waxes Precipitated on Cooling by DSC and Thermomicroscopy,” FUEL, pp. 0–0, 1995, Accessed: 00, 2020. [Online]. Available: