RELATING FEEDSTOCK COMPOSITION TO PRODUCT SLATE AND COMPOSITION IN CATALYTIC CRACKING .2. FEEDSTOCKS DERIVED FROM BRASS-RIVER, A HIGH-QUALITY NIGERIAN CRUDE

The fluid catalytic cracking (FCC) behavior of compound types present in the >650 degrees F resid from Brass River (Nigerian) crude was inve stigated. Liquid chromatography and distillation were employed for sep aration of selected compound type fractions from the resid; the result ing fractions were then cracked using a bench scale FCC unit. The FCC behavior for each compound type was defined in terms of the resulting product distribution (yields of gas, gasoline, etc.) sulfur and nitrog en partitioning, and in selected cases, gasoline composition. Results obtained from Brass River fractions were compared to those obtained fr om an earlier FCC study of compound types from Wilmington, CA, > 650 d egrees F resid. Correlations were derived for gasoline and coke yields from feedstocks derived from either crude. Brass River is a sweet, pa raffinic crude which gives rise to a >650 degrees F resid with very fa vorable FCC characteristics. Although the bulk of the FCC gasoline was produced from cracking hydrocarbon types present, significant gasolin e production also occurred from heteroatomic compounds (acids/bases) i n Brass River. Conversely, negligible gasoline production was observed previously from cracking Wilmington acid/base types. However, feedsto cks from both crudes exhibited greater conversion of sulfide sulfur to H2S compared to thiophenic forms of sulfur, and greater carryover of acidic forms of nitrogen (e.g., carbazole) compared to basic forms (e. g., quinoline). Overall gasoline composition depended on hydrocarbon t ype composition of feedstocks but was also influenced by presence of a cids and/or bases in the feed. On the other hand, the detailed distrib ution of isomers within a given gasoline homolog, e.g., C-3-benzenes o r C-9 isoparaffins, was nearly independent of feed composition. Result s obtained for Brass River will serve as benchmarks for future FCC dat a obtained from low-quality feedstocks.