Synthesis of Carbon Nanofibers from Decomposition of Liquid Organic Waste from Chemical and Petrochemical Industries

Abstract

This work investigates the possibility of using electrocracking for the decomposition of liquid organic waste from chemical and petrochemical industries. This approach yields a gas containing 22-23% acetylene and a wide range of valuable products from lower olefins, paraffin, and hydrogen. The acetylene concentration reported herein is unattainable by other processes for the production of acetylene from hydrocarbon feedstock, and this method is more environmentally friendly than the carbide method. Electrocracking gas is a very promising raw material for the synthesis of carbon nanostructures and carbon nanofibers (CNFs) in particular, and its use for these purposes creates viable preconditions for the establishment of an integrated technology for the utilization of liquid organic waste. The electric discharge process has a marked advantage in that the electric power consumption is low (8-10 kW.hr per 1 m3 of C2H2). The growth of carbon nanofibers from the Ni-Al2O3-catalysed decomposition of electrocracking gas at temperatures of 250–550 °C and electrocracking gas space velocities of 1500-3000 h-1 has been investigated in a fixed bed reactor. Scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and Raman spectroscopy were used to characterize the nanofibers. We demonstrate that carbon nanofibers with diameters mostly between 21.3 and 60.6 nm can be synthesized uniformly and densely on the catalyst