Nano carbon fiber multilevel nonwovens for catalytic upgrading of coal pyrolysis tar

Low-rank coal pyrolysis catalysis is being developed more quickly than ever, and occupies an increasing share in the coal chemical industry field over the past 10 years. The activity and recyclability of catalysts has become one of the main factors limiting low-rank coal pyrolysis development. In this work, nano carbon fiber multilevel nonwovens with a three-dimensional (3D) cavity structure were successfully prepared as a catalyst support to increase the specific surface area and reduce air flow resistance. Manganese oxalate (MnC ₂ O ₄ ) was used as a catalyst precursor. The pyrolysis products and their relative contents of coal were tested by pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The results indicated that the content of fatty hydrocarbons and derivatives was significantly reduced, and the relative content of compounds containing -N, S was also decreased after adding the catalyst. The content of benzene increased from 2.04% to 4.63%. The relative content of polycyclic aromatic hydrocarbons with 4–6 rings was significantly reduced from 0.55% to 0.17%. Due to their 3D cavity structure, nano carbon fiber multilevel nonwovens contribute to the improvement of tar quality and play an important role in catalytic upgrading of coal pyrolysis tar. The catalyst supported by carbon nanofiber carrier also has good recyclability by burning of the carbon nanofiber.