Cocarbonizationproperties of three dewaxed FCC DOs were studied with a low sulfur crude vacuum residue (LSVR) as complements to obtain better quality needle coke. The needle coke lump produced by cocarbonization in the tube bomb was evaluated in terms of its coefficient of thermal expansion (CTE) and amount of bottom mosaic coke. All initial DOs formed very large amounts of bottom mosaic coke in the cocarbonized lumps, while their middle portions were of excellent needle coke. One of dewaxed DOs produced an excellent quality coke without any bottom mosaic coke, whereas others produced a very little of the former and a significant amount of the latter.the blend of LSVR and original DOs. Higher carbonization temperature appeared favorable to obtain lower CTE of the carbonized dewaxed DOs.The analyses of light aromatic fractions in dewaxed DOs indicate that extent of alkyl substitution and its length are fairly different from each other, and that higher aromaticity of the fraction in both terms is favorable to eliminate bottom mosaic coke. The optimum carbonization temperature, which is influenced by the dewaxing, is also discussed in relation to the structure of carbonization feed.
Cocarbonizationproperties of a particular FCC decant oil (FCC-DO) of paraffinic nature with low sulfur vacuum residue (LSVR) were studied in an attempt to find guiding principles of its thermal modification for production of better quality needle coke, using a tube bomb, as these oils do not always make excellent coke of homogeneous quality because of difference existing in the oils properties. FCC-DO was heattreated under some conditions of temperature and residence time before cocarbonization with LSVR, to eliminate the unfavorable bottom mosaic coke. The heattreatment of FCC-DO removed paraffins and alkyl groups of longer chains on aromatic ring, which increased the aromaticity. Highly aromatized FCC-DOs increased solvency, at early stage cocarbonization, dissolving viscous mesophase derived from the most reactive portion in LSVR which is believed to cause bottom mosaic structure. The coefficient of thermal expansion (CTE) of the coke was maintained at optimum range for graphite electrodes by selecting adequate carbonization conditions for the particular feed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.