Direct non-thermal plasma regeneration of deactivated HZSM-5 for catalytic pyrolysis of rape straw

Abstract A direct non-thermal plasma (DNTP) method was proposed to remove coke after catalytic pyrolysis of rape straw at atmospheric pressure and room temperature. Through the optical emission spectroscopy (OES) analysis, it was found that the active substances O3 and O were generated inside the deactivated catalyst and reacted violently with the coke. After DNTP regeneration under different voltages of 20 kV, 22 kV, 24 kV, and 26 kV, the residual coke of each regenerated catalyst was almost completely removed, which were 2.65 %, 1.99 %, 1.29 %, and 0.30 %. Compared with fresh catalyst, the specific surface area of Cat-22 increased the most (34.09 %), and the total acid content increased by 24.11 %. The bio-oil obtained by Cat-22 had the highest monocyclic aromatic hydrocarbons content (46.93 %), which was 29.65 % higher than that of fresh catalyst. After fifteen cycles of catalysis-regeneration at 20 kV, it was found that the content of hydrocarbons of the bio-oil sample could be retained at 94.5 % of that in the original catalytic test. Through the DNTP technology based on the theoretical basis to realize the recycling of the catalyst, it will promote the development of biomass field in a more sustainable and cleaner way.