The main objective of this work is to investigate the effect of a set of crude oil emulsion variables, including pH and salt and water contents, upon the microwave demulsification process. A series of batch demulsification runs were carried out to evaluate the final emulsified water content of emulsion samples after the exposure to microwaves. Tests were performed at distinct heating temperatures, using water-in-heavy crude oil emulsion samples containing different salt and water contents and pH. Well-defined temperature programs were established to control the amount of energy applied to the emulsion and, ultimately, the viscosity. Higher microwave demulsification efficiencies were achieved for emulsions containing high water contents, except when high pH and salt contents were simultaneously involved.

The main objective of this work is to investigate the role of two types of ionic liquids, omimBF4 and omimPF6, upon the microwave demulsification process. A series of batch demulsification runs were carried out to evaluate the final emulsified water content of emulsion samples after the exposure to microwaves at distinct ionic liquid concentrations. Tests were performed in a commercial microwave reactor system, using high stable water-in-crude oil emulsion samples containing different salt and water contents. Similar separation tests conducted under conventional heating were investigated for comparisons. Results showed that increasing the concentration of each ionic liquid yields improved demulsification results in both microwave and conventional heating processes. However, the microwave process was always much faster and more efficient than the conventional case. Blank tests without ionic liquid have not produced water separation, which indicates the high stability of the investigated emulsions. In particular, the joint use of omimPF6 (even at low concentrations) and microwave irradiation allows for system demulsification with high efficiency at short time, with some cases even reaching water contents in the range of 1−2% in the final emulsion.

The use of ionic liquids (ILs) as demulsifiers of water-in-crude oil emulsions represents a new field of study. The main purpose of this work is to investigate the effect of five ILs, [C 4 and a set of operation parameters on the demulsification process, including the heating type (conventional and microwave), IL concentration (0.74−8.9 μmol/g), effect of alkyl chain length, and effect of cation and anion type on demulsification efficiency. The results indicated that the demulsification was favored when more hydrophobic ILs and longer cation alkyl chains were employed, such as [C 12 mim] + [NTf 2 ] − , reaching values close to 92% of water removal. Moreover, the joint use of microwaves and hydrophobic ILs allowed us to maximize the demulsification efficiency.

ABSTRACT:The main objective of this article is evaluating the influence of average polystyrene particle size upon the near-infrared (NIR) spectra collected during suspension polymerization experiments and observing whether NIR spectroscopy may be used for in-line monitoring and control of average particle size. It is shown that NIR spectra are sensitive to changes of the average particle size, and that standard empirical models (PLS-partial least squares-and NN-neural networks) may be built to correlate average particle size and light absorbance at certain wavelengths fairly well. Finally, it is shown that these models allow the in-line evaluation of average particle size in styrene suspension polymerizations with NIR spectroscopy.

ABSTRACT:In a previous paper, Santos et al. (J Appl Polym Sci 1998, 20, 1737 showed that NIRS may be used efficiently for in-line evaluation of average particle sizes in styrene suspension polymerizations if proper calibration is carried out with the help of both multivariate techniques and nonlinear models. In the present work, the technique presented by Santos et al. was used for in-line evaluation and for control and design of average particle sizes during styrene suspension polymerizations carried out in the batch mode. The effects of agitation speed and stabilizer concentration on the particlesize Distribution (PSD) were investigated. It is shown here that this technique allows the successful design and real-time control of particle sizes in lab-scale styrene suspension polymerization reactors.

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Asphaltenes are defined as the petroleum fraction insoluble in n-alkanes and soluble in aromatic solvents, such as toluene. Such definition implies that asphaltenes are not a homogeneous material but a mixture of fractions. Asphaltenes represent one of the major contributors to several problematic issues for the petroleum industry. Destabilized asphaltenes can cause arterial clogging within pipelines and wellbores, corrosion and fouling of production equipment, reduction of catalyst activity in refining processes, and other problems. This work describes an investigation of the separation of asphaltenes into three different fractions by adsorption onto silica particles. These fractions (two adsorbed and one non-adsorbed onto silica) were characterized by elemental analysis (C, H, and N), Fourier transform infrared spectroscopy coupled to attenuated total reflectance (ATR−FTIR), proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI−FT-ICR MS). APPI−FT-ICR MS and ATR−FTIR accessed chemical information on a molecular level [molecular formula, carbon number (CN) and double bond equivalent (DBE) distributions, and organic groups], whereas 1 H NMR and elemental analysis provided the aromaticity degree and C/H atomic ratio of the samples, respectively. The C/H atomic ratio decreases in the following the order: non-adsorbed > whole asphaltene > adsorbed > irreversibly adsorbed. The irreversible fraction adsorbed had the lowest percentage of aromatic hydrogen compared to other fractions by 1 H NMR. There was a good correlation between the results of NMR and elemental analysis. The efficiency of fractionation on silica particles was proven to be successful by the low concentration of polyaromatic hydrocabons observed for two samples adsorbed onto silica and the increasing of the aromaticity degree and C/H ratio for the non-adsorbed fraction. N 2 , N 2 O, and NO compound classes were selectively separated from whole asphaltene and concentrated in polar fractions (adsorbed fractions onto silica), with their CN and DBE distributions reported. Therefore, this work demonstrated the selectivity of the fractionation method onto silica to retain highly polar compounds and, moreover, extends to the study of the adsorbent surface and how the molecules of the asphaltenes will behave against this change.

ABSTRACT:A conductivity meter is an inexpensive instrument that can easily be installed in polymerization reactors. This instrument can be used to monitor ionic species without time-consuming calibrations. A probe is inserted into the media, providing in situ measurements of conductivity in real time. For emulsion polymerization reactions, the conductivity meter can respond to changes in the ionic surfactant concentration, allowing the determination of surfactant dynamics in the media. The surfactant concentration can then be related to the changes in the surface area of the polymer particle phase, which can be linked to nucleation or coagulation phenomena. In this study, a conductivity meter was coupled to a calorimetric reactor to provide in situ and online measurements of conductivity during the emulsion polymerization of styrene, with sodium dodecyl sulfate as an anionic surfactant and with potassium persulfate as a free-radical initiator. A semiempirical model was built to describe the conductivity signal as a function of the latex composition and the reactor temperature. The model was inverted and combined with the available conductivity signal, conversion, and temperature measurements and was able to accurately predict the number of polymer particles in the latex and the surfactant concentrations in the many phases, without online measurements of the particle size.