Characterization of cokes from fluid/flexi-coking of heavy feeds

Several streams of coke particles which are generated during the fluid/flexi-coking operation vary in chemical and physical properties. At least six and eight coke streams can be identified in the fluid-coking and flexi-coking mode, respectively. The final coke residue disposed from the operation, particularly from the fluid-coking, is the most important because its storage and utilization require attention. Difference in chemical composition between the fluid-coke and flexi-coke confirm that the latter was exposed to more severe conditions. The layered structure of the coke particles was typical for both fluid-coke and flexi-coke. The surface area of the latter was greater and mean particle diameter smaller than that of the fluid-coke. With respect to a fuel type utilization, an uncertainty exists between the reactivity of the fluid-coke relative to that of the flexi-coke.