Ribbon coke

Ethane pyrolysis at 800°C in SS 304 reactor fluffy (or gas phase) and ribbon cokes. 

Shot Ribbon and lenticular anisotropic domains arranged in concentric patterns to form shotlike coke... 

A—Pyrolytic carbon showing ribbon-like structure in vitrinoid bands. B—Faint gray lines define compression cracks in a bright micrinoid particle. C—Pyrrhotite (white) formed by the thermal decomposition of pyrite impregnating semifusinoids (gray). D—Bright coke particles in a baked-bone coal layer... 

Typical pilot plant operation began by preparing an intimate mixture of ground coke and KOH in a ribbon blender in a range of KOH/coke weight ratios of 2 to 4. The blend was stored in N2" blanketed and sealed drums. 

Coke formed on solid surfaces during the pyrolyses of acetylene, ethylene, ethane, propylene, and butadiene were examined by using a scanning electron microscope. Seven types of coke have been identified braided filament, uniform diameter filament, needle or spike, ribbon, fluffy or cottonlike fibers, knobby, and amphorous. The first four types contained metal (especially iron) and were magnetic. Magnetic cokes formed sometimes on Incoloy 800, stainless steel 304, stainless steel 410, and Hastelloy X surfaces, but never on Vycor glass or aluminized Incoloy 800 surfaces. Conditions at which each type of coke was formed are discussed. 

Why was iron the predominant metal in filament, ribbon, and needle cokes Further information on the mechanism of coke formation is needed. 

Ribbonlike parallel-ordered anisotropic domains that can also occur as folded structures Lenticular anisotropic domains of various sizes that are not aligned parallel to the particle surface Ribbon and lenticular anisotropic domains of various sizes in curved and irregular layered arrangements Porous microstructure with walls that are generally anisotropic but with pores and walls that vary in size Ribbon and lenticular anisotropic domains arranged in concentric patterns to form shothke coke Isotropic carbon form closely associated with parent hquor. Higher in volatile matter than incipient mesophase... 

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