viscosity

The formation of aggregates of a fraction of asphaltenes extracted from Brazilian crude oil was investigated by measuring the interfacial tension and kinematic viscosity of their solutions prepared in different solvents. The interfacial tension results indicate the existence of critical micelle concentration (CMC) levels of the asphaltenes in solvents with solubility parameters sufficiently different from those of the asphaltene tested. The kinematic viscosity measures revealed the formation of aggregates at concentrations above the CMC.

Evaluations of wax inhibitors carried out in laboratories are generally performed on stabilized oil samples, that is, without the presence of natural gas and at atmospheric pressure. Therefore, the effects of two important factors that influence wax solubility – the light fractions and temperature – are not considered, and the results may not reflect what really happens in production lines and facilities.

Kinetic scheme of formation of molecule fluctuations in gas and liquid phases is proposed. Distribution of molecule number in molecule fluctuations on the number of molecule fluctuations in the unit volume of the system is calculated. Correlation equations for surface tension, liquid viscosity and molecule number in molecule fluctuations in gas and liquid phases as well as correlation equation between saturation vapour pressure, liquid density and temperature are proposed.

The physico-chemical regularities of polypropylene microfibers obtained via processing polypropylene/copolyamide (PP/CPA) mixture melts filled with nanosilicas have been investigated. It has been shown that the chemical nature of silica functional groups affects the viscosity of PP/CPA melts. In spite of the solid state of additives the filling effect does not occur or reveals weakly. Silicas do not prevent the polypropylene fiber-forming in a copolyamide matrix but improve it. This is explained by the stabilizing action of silica additives on PP liquid streams.

The work is devoted to the development of alternative jet fuel blended with rapeseed oil-derived biocomponents and study of their physical-chemical properties. The modification of conventional jet fuel by rapeseed oil esters was chosen for this work among the variety of technologies for alternative jet fuels development. The main characteristics of conventional jet fuel and three kinds of biocomponents were determined and compared to the standards requirements to jet fuel of Jet A-1 grade.