No abstract

No abstract

Asphaltenes flocculate as a consequence of changes in the temperature, pressure, or composition. This flocculation can result in several oil production problems. The application of chemical additives (inhibitors or dispersants) is a well-known way to control asphaltene flocculation. Ultraviolet−visible (UV−vis) spectroscopy is the most common analytical technique that has been applied to study the effectiveness of chemical additives in keeping asphaltene particles dispersed into crude oils. However, this technique requires being performed in diluted solutions, which can interfere significantly in the aggregation phenomena. The objective of this work was to evaluate the effect of three chemical additives, 4-dodecyl benzenesulfonic acid (DBSA) and two commercial products (C0 and C1), on the asphaltene aggregation behavior of two Brazilian crude oils, using near-infrared (NIR)-laser (λ = 1550 nm) scattering measurements. This is a new methodology developed to study the aggregation kinetics and settling of asphaltenes around its n-heptane flocculation onset. The NIR-laser scattering method offers the possibility to work with samples at a higher crude oil concentration, being more representative of real systems. The results obtained were compared to those determined with the traditional UV−vis method (λ = 850 nm) and showed qualitatively similar trends. Settling measurements suggest that the stabilization provided by the additives can occur by slowing both formation and growing of asphaltene particles and delaying the phase separation process. DBSA was more effective in keeping the asphaltene particles dispersed in solution and prevented them from settling at lower concentrations when compared to commercial products, for both crude oils studied. It was demonstrated that the methodology developed using NIR-laser scattering was more accurate and sensitive.

No abstract

-In this work, the recovery of base oils from waste lubricants following the steps of solvent extraction, adsorption on solids and solvent removal by evaporation was evaluated. In the step of solvent extraction, the most efficient was 1-butanol, followed by tert-butanol, 2-propanol and ethanol; for the step of adsorption, activated carbon was the most effective solid for PAH removal, confirming the similarity of these compounds with petroleum aromatic fractions. Thus, the optimum solvent-adsorbent pair for the recovery of used lubricant oils through the proposed methodology was 1-butanol/activated carbon. At the end of the process, it was possible to establish a set of steps that permit the recovery of lubricant base oils with lower content of contaminants.

No abstract

Waste lubricant oils are products that undergo degradation due to their use, yielding substances that are potentially carcinogenic, such as PAHs (polycyclic aromatic hydrocarbons), which renders them improper. In this work, a sequence of physical steps was investigated focusing on the adsorption on solids for PAHs removal. Adsorption isotherms were constructed considering the PAHs concentration capacity presented by different solids, with activated carbon as the most efficient adsorbent in the removal of PAHs. At the end of the process it was possible to reestablish the main properties of the base oil, and to propose a methodology for the recovery of the base oil, comprising solvent extraction, adsorption on solid surfaces and solvent distillation, making it adequate to be reintroduced into the production chain.

A espécie de abacaxi Ananas comosus (L.) Merr. abrange todas as cultivares de interesse frutícola, algumas endêmicas do Brasil. Este trabalho traz um levantamento de pesquisas e tecnologias relacionadas ao abacaxi (Ananas comosus), com o propósito de ressaltar sua importância e de estimular pesquisas de novas tecnologias. A prospecção científica foi realizada nas bases Scopus e Web of Science, e a tecnológica, nas bases Espacenet (EPO), USPTO, Derwent e Patenscope (WIPO), além das ferramentas The Lens e Patent Inspiration. Na Scopus foram obtidos 2.314 resultados e na Web of Science, 3.199. No Brasil, os números foram, respectivamente, 451 e 614. As bases Derwent, Espacenet (EPO), Patenscope (WIPO), USPTO, Lens e Patent Inspiration levaram a um total de 192 patentes. Pela Cooperative Patent Classification (CPC), há concentração de patentes nas áreas de agricultura, ciências da vida, bebidas e bioengenharia.