Abstract: The Reid Vapor Pressure of a hydrocarbon mixture consisting essentially of hydrocarbons selected from the same series is determined based on the actual temperature and vapor pressure of the hydrocarbons mixture. The thus determined Reid Vapor Pressure may be compared to a set point for the Reid Vapor Pressure with the results of the comparison being utilized to maintain the actual Reid Vapor Pressure substantially equal to the desired Reid Vapor Pressure.

Abstract: Method and apparatus for fractionating a hot vaporous hydrocarbon feed from a fluid catalytic cracking reactor wherein the hot vaporous feed is introduced into a fractionator zone near one end thereof and liquid is removed from a liquid collection zone and cooled in a heat extraction zone. A first portion of the cooled liquid is returned to a location between the liquid collection zone and the point of introduction of the vaporous feed and sprayed directly on hot condensed liquid flowing downwardly over an inclined baffle plate to quickly quench the liquid below the temperature at which polymerization of the constituents of the liquid can occur.