Fluid Properties at Coking Process Conditions

A new method based on the measurement of the forces on a liquid bridge between two crossed rods was used to determine fluid properties during the cracking of an Athabasca vacuum residue at 300−530 °C. The surface tension was measured at temperatures between 312 and 530 °C. Adhesive forces in the liquid bridge and viscosity were measured with increasing reaction time at 400−530 °C. The results showed that the adhesive force remained constant, until the liquid dried out because of devolatilization and coke formation, where it fell to zero. The surface tension was constant with increasing reaction time, but it decreased with reaction temperature from 21 mN/m at 150 °C to 6 mN/m at 530 °C. The viscosity increased to order 10 4 mPa·s before dry-out, for all of the temperatures above 400 °C.