Properties of fluid catalytic cracking decant oils of different origins in their single carbonization and cocarbonization with a petroleum vacuum residue

Abstract

Eight decant oils of fluid catalytic cracking (FCC-DO) were compared in terms of their structure and carbonization properties in their single carbonization and cocarbonization with a low sulfur vacuum residue (LSVR) to reveal structure-reactivity correlation in the needle coke production. Although eight oils all provided (at 500{degrees} C under 16 kg/cm{sup 2} of pressure) lumps of needle cokes in a tube bomb, their coefficients of thermal expansion (CTE) ranged from {minus}0.15 {times} 10{sup {minus}6} (shrink, oil E) to 0.6 {times} 10{sup {minus}6}{degrees} C{sup {minus}1} (oil A). Their cocarbonization with LSVR at 480 {degrees} C under 8 kg/cm{sup 2} provided lump cokes of variable quality in terms of CTE and amount of bottom mosaic cokes. It should be noted that the best FCC-DO in its single carbonization was not always a better partner in the cocarbonization. In the cocarbonization, the best FCC-DO (G) gave a needle coke with the low CTE of 0.6 {times} 10{sup {minus}6}{degrees} C{sup {minus}1} and no bottom mosaic cokes while the worst oil (A2) gave a CTE of 1.2 {times} 10{sup {minus}6}{degrees} C{sup {minus}1} and bottom mosaic coke 1.4 mm thick. The oils consisted principally of saturate and light and heavy aromatic fractions, the contents of whichmore » varied from one oil to another. The roles of FCC-DO in the cocarbonization particularly in the formation of bottom mosaic texture, are discussed.« less