Abstract: A method for detecting the formation of at least one phase in a mixture, particularly a hydrocarbon mixture. The method may include using a probe to expose a portion of the mixture to electromagnetic radiation to determine the value of a parameter of interest indicative of the formation of a phase. The method may also include using the value of the parameter of interest with a correlation between a known property of the mixture and the value of a parameter of interest to detect the formation of a phase.

Abstract: Near IR spectroscopy may be used for determining the coke generation tendency of a hydrocarbon. The coke generation tendency of hydrocarbons may be used to control refining conditions. An apparatus for determining the coke generation tendency of hydrocarbons comprising a near infrared spectrophotometer and other components may be used to make the determinations continuously.

Abstract: Quench oil aging and its propensity to cause fouling may be evaluated by determining the amount of a precipitant necessary to cause the flocculation of polymer species present in the quench oil. The propensity of quench oil to cause fouling may be used as a basis to mitigate fouling in cracking processes.

Abstract: Heavy fuel oils or residual fuel oils can be stabilized with magnesium over-based compounds such as magnesium overbased carboxylates. It was surprisingly discovered that adding magnesium overbased carboxylates to the residual fuel oils shortly after thermal cracking gave much better results than can be achieved after the application of the carboxylates to the fuel oil after storage. Further, compounds containing at least about 21 wt % magnesium also give better results than compounds with 18 wt % or less, in one non-limiting embodiment. Magnesium overbased compounds can also be added to coker feedstocks to reduce coker furnace fouling. Treatment with the methods of this invention reduces asphaltene deposits and sludges.