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Re´sume´-Proprie´te´s thermophysiques des solutions aqueuses de sels 1:1 avec l'e´quation d'e´tat de re´seau pour e´lectrolytes -L'e´quation d'e´tat, dite e´lectrolattice, est un mode`le qui e´tend l'e´quation d'e´tat de Mattedi-Tavares-Castier a`des syste`mes avec e´lectrolytes. Ce mode`le prend en compte l'effet de trois termes. Le premier terme est base´sur les trous dans le re´seau en conside´rant les effets de la composition locale, e´tude effectue´e dans le cadre de la the´orie ge´ne´ralise´e de Van der Waals : l'e´quation d'e´tat de Mattedi-Tavares-Castier a e´te´choisie pour ce premier terme. Les deuxie`me et troisie`me termes sont les contributions de Born et du MSA. Ils tiennent compte du chargement et du de´chargement des ions, et des interactions ioniques al ongue distance, respectivement. Le mode`le n'ayant besoin que de deux parame`tres d'interaction e´nerge´tique, il mode´lise de manie`re satisfaisante la pression de vapeur et le coefficient d'activiteí onique moyenne pour des solutions aqueuses simples contenant du LiCl, LiBr, LiI, NaCl, NaBr, NaI, KCl, KBr, KI, CsCl, CsBr, CsI, ou du RbCl. Deux me´thodes pour obtenir les parame`tres du mode`le sont pre´sente´es et mises en contraste : une me´thode spe´cifique pour le sel en question et une autre base´e sur les ions. Par conse´quent, l'objectif de ce travail est de calculer les proprie´te´s thermophysiques qui sont largement utilise´es pour la conception, l'exploitation et l'optimisation de nombreux proce´de´s industriels, parmi eux le dessalement de l'eau.Abstract -Thermodynamic Properties of 1:1 Salt Aqueous Solutions with the Electrolattice Equation of State -The electrolattice Equation of State (EOS) is a model that extends the MattediTavares-Castier EOS (MTC EOS) to systems with electrolytes. This model considers the effect of three terms. The first one is based on a lattice-hole model that considers local composition effects derived in the context of the generalized Van der Waals theory: the MTC EOS was chosen for this term. The second and the third terms are the Born and the MSA contributions, which take into account ion charging and discharging and long-range ionic interactions, respectively. Depending only on two energy interaction parameters, the model represents satisfactorily the vapor pressure and the mean ionic activity coefficient data of single aqueous solutions containing LiCl, LiBr, LiI, NaCl, NaBr, NaI, KCl, KBr, KI, CsCl, CsBr, CsI, or RbCl. Two methods are presented and contrasted: the salt-specific and the ion-specific approaches. Therefore, the aim of this work is to calculate thermodynamic properties that are extensively used to design, operate and optimize many industrial processes, including water desalination.

In oil industry, oil emulsions are recurring problems and them can be oil in water (A / O) or water in oil (A/O) type. An alternative currently studied for breaking emulsions is the use of Microemulsionated Systems (MS) that have the characteristic of solubilizing polar and nonpolar substances. The objective of this work was the synthesis of a surfactant from a vegetable oil, as well as the formulation of microemulsion for breaking emulsions of type A/O. For the synthesis of the surfactant, Moringa Oleifera Lam oil was saponified and characterized by Saponification Index and Hydrophilic-Lipophilic Balance. The microemulsion systems were formulated using Saponified Moringa Oil as Surfactant (S), n-butanol as cotensoactive (C), moringa oil as oily phase and distilled water as aqueous phase and the ratio C/S was varied at 1, 5 and 10. To validate the results of emulsion break the Scheffé's network was employed. The oil was characterized according to ABNT NBR 14647 and had a BSW (Basic Sediments and Water) content of 24%. The results showed at the end of the experiments of 30 minutes an aqueous phase separation efficiency of 40%. Furthermore, it was found that the relationship between the microemulsion concentration and the separation percentage is not linear, and the biggest gain in the separation efficiency occurs for lower concentrations (about 8%). Therefore, the study made it possible to investigate the capacity of microemulsion systems developed to break A/O emulsions, as well as to optimize the microemulsion concentration to be used in the process.

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The formation and deposition of elemental sulfur (S 8) in natural gas pipelines are a frequent problem. The formation of a yellow powder, which is known as S 8 , is influenced by operational condition changes, such as pressure and temperature drops, natural gas composition, and additives used in pipelines. S 8 may occur in pipelines due to the desublimation of sulfur dissolved in natural gas, where it changes into a solid state. This phenomenon may lead to serious consequences to gas production, processing, operation, and transportation. The objective of this study is to better understand the kinetics and operational variables that influence S 8 formation to find solutions for reducing or eliminating the occurrence of this compound during natural gas transportation in pipelines.