STUDIES REVEAL SHOT-COKE MICROSTRUCTURE, SUGGEST WAYS TO MINIMIZE ITS FORMATION.

The microstructure of shot coke has been revealed by experimental studies of the formation of various petroleum cokes by carbonization of heavy resids. The results of these experimental studies indicate the mechanisms responsible for the formation of shot coke, and they suggest procedures to minimize the formation of shot coke in commercial delayed cokers. The structure of shot coke is described by the use of Montage microphotographs, comparing the structure to that of sponge coke. The photographs reveal the fine-mosaic, high-density structure of shot coke. Previous studies indicate that shot coke appears to be encountered more frequently when processing heavy resids. Marsh, et al., and Derbyshire, et al., observed the fine-mosaic texture of shot coke and discussed the mechanism of its formation. Additional information regarding the formation of shot coke is described in NPRA Q and A transcripts. Lieberman suggests the growth of shot coke and its settling in the liquid phase. This study provides additional information to help decrease the formation of shot coke.