![]() The stabilization of the dispersed droplets within PEs is ensured by a strong adsorption of the solid particles at their surfaces. The stabilization of larger droplets (few millimeters diameter) is possible as well, using micron-sized solid particles. The solid particles that act as emulsifiers are of nanometric size, while the stabilized droplets are as small as few micrometers diameter. Both droplets and continuous phase contain different molecules (chemically incompatible macromolecules, for instance), which are entirely water-soluble. Also, PEs may be water-in-water (W/W) emulsions, which are dispersions formed by droplets of water-solvated molecules moving in another continuous aqueous solution. These particles may be organic or inorganic, according to the nature of their desired use. These dispersions are stabilized by an addition of small solid particles that act as emulsifiers, instead of the surfactant molecules. Pickering emulsions (PEs), are dispersions presenting, very often, as oil-in-water (O/W), water-in-oil (W/O) or double emulsion water-oil-water (W/O/W). Finally, we precise the major role played by grafted polymers onto the spherical oil/water interface. ![]() The question (3) is concerned with an exact study of the spherical diffusion of anchored nanoparticles on the surface of the dispersed oil-droplets. The question (2) deals with a quantitative investigation of the clothed oil-droplets dynamics (cage effect and subdiffusion), using a Generalized Langevin Equation, which is successfully tested by Molecular Dynamic Simulations. To this end, the adopted pair-potential is that of Sogami-Ise combining repulsive and attractive forces, and use is made of the so-called Integral Equation Method. For question (1), we recall the essential steps allowing the determination of the structure-factor and the spatial-correlation function, and the thermodynamic properties, as pressure, internal energy, and thermal compressibility of these emulsions. For the study, the emulsions are regarded as colloidal solutions, where the clothed oil-droplets play the role of charged soft-colloids, and in addition, the adsorbed nanoparticles are assumed to be point-like. Here, we are concerned with three important questions: (1) Structure and thermodynamics of these emulsions, (2) cage effect and subdiffusion phenomenon within them, and (3) spherical diffusion of anchored nanoparticles on the curved oil/water interface. The findings in this research can provide further knowledge that can enhance the safe transportation of CO2 in pipelines under stable hydrate forming conditions.In this review paper, we report on some very recent findings dealt with the oil-in-water Pickering emulsions, stabilized by a strong adsorption of charged solid nanoparticles on the surface of the oil-droplets. Presently, there is a growing concern regarding the potential leakage of CO2 in pipelines (Lu et al., 2020 Wang et al., 2022 Wareing et al., 2016), which may escalate due to pipewall corrosion caused by hydrates (Obanijesu, 2012). Two shear stress regimes have been identified for hydrate sloughing and pipewall shedding in this study, with the latter resulting in higher shear stress on the pipewall. The conversion of the consumption rate of natural gas to hydrates was achieved using the equation proposed in the literature (Umuteme et al., 2022). The study shows that the simulated temperature contours align well with the reported hydrate deposition profile in gas pipelines (Di Lorenzo et al., 2018). We have deduced the presence of hydrates based on the stable temperature profile of natural gas hydrates along the pipeline model. In this study, a computational fluid dynamics (CFD) simulation approach is employed using a validated CFD model from the literature for predicting hydrate deposition rates (Umuteme et al., 2022), by applying a subcooling temperature to the pipe wall at hydrates-forming condition. While sloughing occurs within the deposit of hydrates, pipewall shedding is related to direct interaction of the gas phase with the thin layer of hydrates on the pipewall. ![]() Similarly, pipewall shedding by hydrates involves the direct interaction of hydrates with the pipeline inner surface, resulting in the detachment or removal of hydrate deposits from the pipewall. Hydrate sloughing is the peeling off of some hydrate deposits from the pipeline inner surface. The continuous flow assurance in subsea gas pipelines relies heavily on the assessment of temperature profile during hydrate sloughing and pipewall shedding caused by hydrates, with similar implications for carbon dioxide (CO2) transportation under hydrate-forming conditions. ![]()
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