(166a) Isokinetic Phenomena in Crude Oil Fouling

Our studies of crude oil fouling have revealed two manifestations of the isokinetic phenomenon. First, initial fouling rates of four proprietary crude oils clearly exhibit an isokinetic temperature in the middle of their Arrhenius plot. A plot of natural logarithms of pre-exponential factors versus apparent activation energies is linear, confirming the validity of the isokinetic temperature and indicating the presence of the compensation effect. Second, the initial fouling rates of Maya crude oil and styrene fouling systems become velocity-independent, thereby creating another isokinetic condition, at temperatures of 274 °C and 77 °C, respectively. The compensation effect is also observed in the Maya crude oil and styrene systems but here the linearity in the logarithms of pre-exponential factors with apparent activation energies is due to changes in velocity instead of changes in fluid type. This paper will discuss the background of the compensation effect and its manifestation in the isokinetic phenomenon.