Phase transitions of petroleum waxes in hydrocarbon solvents of different chemical nature

Abstract

Phase transitions of petroleum waxes and of oil well wax deposits in aliphatic and mixed hydrocarbon solvents were studied by differential scanning calorimetry. n-Undecane and gas condensate were used as aliphatic solvents straightly and as binary and ternary mixtures with cyclohexane and p-xylene. The temperature at which the petroleum and oil well waxes start to crystallize is lower in binary aliphatic–aromatic systems than in aliphatic solvents. The degree of crystallinity of waxes is maximal in aliphatic solvents and minimal in aliphatic–aromatic and aliphatic–naphthene–aromatic systems, which is in agreement with the morphological features of the samples studied. The results obtained led to a conclusion that it is appropriate to use gas condensate compounded with aromatic concentrates for removing wax deposits, in particular, at low stratum temperatures.