Quality of distillates from coking of recycled residue.

摘要

The yields of gas, liquid and coke from the coking of Athabasca vacuum residue were determined as a function of conversion of the residue. High conversion was achieved by subjecting the unconverted residue to repeated coking steps. The distillate and the residue material obtained at each coking step were characterised using various analytical techniques.;There was a 12% increase in the cumulative yield of liquid from stage 1 of coking where 82% residue conversion was obtained, to stage 3 where 99% cumulative residue conversion was obtained. The quality of the distillates obtained at each stage deteriorated based on the amount of nitrogen and polynuclear aromatics. It was also observed that although coking reactions resulted in a decrease in the number of aliphatic chains, the average chain length remained constant. A mass balance showed that the aromatic carbon increased in the first coking step, then remained constant.