Multicomponent [CoFeNi]Cux Alloys for the Catalytic Pyrolysis of C2+ Hydrocarbons Mixed with Methane

An approach to conditioning associated petroleum or natural gas has been described. The method is based on the catalytic pyrolysis of C1–C4 light hydrocarbons in the presence of multicomponent alloy particles. In this process, the C2–C4 hydrocarbon fraction undergoes pyrolysis to form hydrogen and carbon nanofibers (CNFs) that accumulate on the catalyst. The highest activity in the decomposition of a C2–C4 mixture is exhibited by an equiatomic [CoFeNi] alloy promoted with 7 at % of copper ([CoFeNi]Cu7). The maximum CNF yield at 650°C is 106 g/gcat within 30 min. It has been shown that this alloy can be effectively used for the catalytic decomposition of the C2–C4 fraction mixed with methane. The dependence of the CNF yield on the C2–C4 fraction concentration in the model mixture has been determined. It has been found that during the pyrolysis of a mixture with a volume ratio of C2–C4/СH4 = 10/90, the catalyst does not undergo any significant deactivation within 30–180 min. The CNF yield after 180 min of reaction is 160 g/gcat. The average conversion of the C2–C4 fraction per pass is 20%. The morphology and structure of the synthesized CNFs have been studied by scanning and transmission electron microscopy and low-temperature nitrogen adsorption methods.