SEPARATION AND CHARACTERIZATION OF PARAFFINS AND NAPHTHENES FROM FCC FEEDSTOCKS

A separation technique was developed for the characterization and iden tification of the nonaromatic fraction of a light and a heavy FCC feed stock (gas-oil). The separation of the paraffins was based upon the se lective reaction of n-paraffins with urea and branched paraffins with thiourea. One more method based on the molecular sieves adsorption was also applied for n-paraffin separation, but the urea method was found to be more satisfactory. The total recovery of the method was about 7 0%. All the fractions were characterized using a system of GC/MS under the specific conditions presented in this work. The hydrocarbons in t he n-paraffinic and isoparaffinic fractions were identified satisfacto rily, while for the naphthenic fraction this identification was more d ifficult. A quantitative analysis was attempted of all the paraffinic compounds in the FCC feedstock. Using a standard sample of n-paraffins , the relative wt % concentrations of the n-paraffinic and isoparaffin ic compounds were determined. For the cycloparaffins, the method of AS TM D2786 was applied and the concentrations of naphthenes mere approxi mately estimated according to the number of rings in these compounds.