Temperature Dependent Behavior of Oil Dispersion System in Bulk and on the Metal Surface

摘要

This article focuses on the temperature dependent behavior of oil dispersion systems containing high amount of paraffins. In particular the properties of oils in bulk and during the contact with metal surface were evaluated by methods of rheoviscometry, thermal analysis, differential scanning calorimetry, gravimetry, polarization microscopy, gas chromatography and chemical analysis. Analysis of rheological parameters of oil, morphology of paraffin crystals, and thermal properties at temperature interval between 0÷90 0 С allowed to determine the transition temperature of oil dispersion system from the molecular to free-dispersal and bounded-dispersal states. It was established that the indicated parameters depend on oil composition, molecular-mass distribution of paraffins, curing temperature and cooling rate. Contacting of high paraffinic oils with steel surface leads to formation of asphaltene-resin-paraffin deposition (ARPD). The quantity, structure, composition and adhesiveness of ARPD depends on oil composition and gradient of temperature between heated oil and cooled metal surface. In case of temperature gradient is more than 30 0 С the solid and high adhesive depositions are formed. Their structure is enriched by long chain high-melting paraffins. In case of temperature gradient is less than 20 0 С, amorphous and easy removable depositions are formed. Their structures are enriched by mechanical admixtures, water, resin, asphaltene and low-melting short chain paraffins.