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

Abstract

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/g_cat 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/g_cat. 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.