Ethane coke formed from

Steam cracking (Fig. 2), consists of a furnace in which the cracking takes place is at 815 to 870°C (1500 to 1600°F). As many as 6 to 20 furnaces are in parallel to increase ethylene production. Steam is used as a diluent to inhibit coking in the tubes and to increase the percentage of ethylene formed. The amount of steam changes with the molecular weight of the hydrocarbon feedstock and varies from 0.3 kg steam/kg ethane to 0.9... 

Considerable information was obtained for ethane pyrolysis relative to coke deposition on and to decoking from the inner walls of a tubular reactor. Both phenomena are affected significantly by the materials of construction (Incoloy 800, stainless steel 304, stainless steel 410, Hastelloy X, or Vycor glass) of the pyrolysis tube and often by their past history. Based on results with a scanning electron microscope, several types of coke were formed. Cokes that formed on metal tubes contained metal particles. The energy of activation for coke formation is about 65 kcal/g mol. 

Surfaces B and C for the Incoloy 800 reactor were quite different from the platelets and crystallites formed in the stainless steel 304 and 410 reactors. The metal concentrations for Surfaces A, B, and C varied rather erratically compared with the bulk metal (see Table III). Clearly, further investigations are needed to learn about coke deposits formed during ethane pyrolysis in Incoloy 800 reactors. 

Pt seems necessary for complete removal of the chlorine atoms from TCA. Neither a-alumina nor Ti5-alumina (without Pt) produced any pure hydrocarbons. However, when Pt was added to either support, ethane was observed in the effluent. In addition, ethylene was observed in the effluent when the Pt/a-alumina catalyst was used, suggesting a weaker hydrogenation function for the Pt/a-alumina catalyst compared to the Pt/r 8-alumina catalyst. This weaker hydrogenation function may account for the more rapid deactivation since the unsaturated intermediates may polymerize to form coke. 

Catalytic aromatisation of aliphatic hydrocarbons was first described by researchers at Mobil.2s In this process, termed M-2 forming , alkanes from ethane to high boiling point naphthalenes can be aromatised. The most effective catalyst for aromatisation was found to be the medium pore HZSM-5.26 Large pore zeolite and amorphous silica-alumina with broad pore size distributions gave only low yields of aromatics due to rapid coke formation. 

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