PARAMETERS CRYSTALLIZATION PROCESSES AND SOLID PETROLEUM HYDROCARBONS DISSOLUTION

In the proposed work, the experimental data on the processes of crystallization and different nature waxy hydrocarbons recrystallization in hydrocarbon solvents have been compared. T-1 technical paraffin (GOST 23683-89) with the melting point of 54 °С and ceresin-80 (GOST 2488-79) with the dropping temperature of 80 °C have been used. РТ-1 kerosene (GOST 10227-86) and de-waxed oil of fraction 420-490 °С have been used as hydrocarbon solvents. The experimental data on crystallization and recrystallization processes of paraffin wax with a melting temperature of 54 ºC and ceresin with a dropping temperature of 80 °C in kerosene and dewaxed oil are presented in this paper. It is shown that chemical structure has the main influence on the processes of crystallization and recrystallization of solid petroleum hydrocarbons. An exceedance of solid hydrocarbons solution temperatures tр above their cloud points tп has been observed which is explained by hysteretic processes. The temperature difference Δt = tр- tп depends on the solid hydrocarbons nature and their content in solvents. Wax solutions in kerosene have higher values Δt relative to ceresin solutions in kerosene, which can be explained by the difference in chemical structure of solid hydrocarbons. With the increase in solid hydrocarbons content in their solvents due to the differences in solid hydrocarbons diffusion rate, Δt decreases. The discovered regularities of solid hydrocarbons crystallization and recrystallization should be taken into account in the processes of paraffin oil production, transportation and processing.