Non-thermal plasma assisted catalytic reforming of naphtha and its model compounds with methane at near ambient conditions

The hypothesis of reaction mechanism. Long and unsaturated molecules are preferred to be activated by surface discharge. For these short and stable hydrocarbons like methane and hexane, they are favorable to be activated by the volume discharge. With free radicals generated from the NTP-assisted hydrocarbon activation, iso-paraffins could be produced from the olefins saturation and paraffins isomerization. • Conventional hydrogen is replaced by methane as a cheaper H-donor. • Non-thermal plasma converts methane and naphtha at near ambient conditions. • A fuel with high content of iso-paraffins is produced over Ga/mix-ZSM-5. • Coke generation and the content of olefins and aromatics are well controlled. • A hypothetic reaction mechanism is proposed based on model compound studies. Naphtha reforming processes are widely used for high-octane gasoline production. These processes require high reaction temperature and high pressure of expensive hydrogen. Also, olefins and aromatics are produced for achieving high octane number, which could cause severe environmental issues. Here, we report a novel method of non-thermal plasma assisted catalytic reforming of naphtha at near ambient conditions. Conventionally used hydrogen has been replaced by cheaper methane in this study. Non-thermal plasma could effectively convert methane and naphtha to high-quality fuel at near room temperature and atmospheric pressure. A high-quality fuel with high content of iso-paraffin and low content of olefin and aromatic is produced over optimized Ga/mix-ZSM-5 with non-thermal plasma applied. The produced liquid product has a notably higher iso-paraffin content (increased from 21.5%–40.5%) than raw naphtha while the coke deposition (17.4 %) and the content of olefins (decreased from 13.5%–7.8%) and aromatics (dropped from 18.1%–5.9%) are well controlled. The partial desulfurization of fed coker naphtha by close to 60 % is also successfully achieved. A systematic model compounds study is conducted to investigate the involved mechanism of non-thermal plasma assisted catalytic naphtha reforming and coke deposition. Based on the studies of C 6 -C 16 model compounds (including paraffins, olefins, dienes, cyclo-paraffins, cyclo-olefins and aromatics), a hypothetic reaction mechanism is proposed. A series of control experiments is also carried out to reveal the synergistic effect between non-thermal plasma, catalyst, and methane participation. This research thus pioneers a cost-effective and environmental-friendly route for naphtha reforming at mild conditions.