Promotion of the vapors from biomass vacuum pyrolysis for biofuels under Non-thermal Plasma Synergistic Catalysis (NPSC) system

Highlights: • Non-thermal Plasma Synergistic Catalysis was established for biofuels preparation. • Multiple interactions existed in three-way catalysis improved fuel grade of bio-oil. • The "isomorphism" for coke I and coke II appeared while Ti was introduced in NPSC. • (H/C)_eff of reactant should be improved to enhance hydrogen transfer process. Non-thermal Plasma Synergistic Catalysis (NPSC) was firstly proposed and employed in the upgrading of biomass pyrolysis vapors for preparation of biofuels. The effects of the three-way catalysis (non-thermal plasma, HZSM-5 body and modified components) on the bio-oil upgrading performance and catalyst stability were comprehensively investigated. Bio-oil yields continued to decrease, but the physicochemical properties were further improved. The contents and compositions of hydrocarbons in bio-oil were increased and improved to varying degrees. The introduction of non-thermal plasma technology enhanced performance of cracking and deoxygenation for whole catalytic process. Besides, anti-coking performance of Zn/HZSM-5 was enhanced to a certain extent, but the multiple interactions significantly improved the cracking performance when Ti species introduced, increased the coke content, and an "isomorphism" phenomenon for two kinds of coke was emerged. In general, obtained biofuels still belonged to the hydrogen-deficient fuel, lower (H/C)_eff of the vapors limited substantial improvement of the fuel grade.