Cold model testing of in-situ catalyst activation by swirling self-rotation in ebullated bed reactor for biomass pyrolysis oils hydrogenation.

• A self-rotation of catalyst particles in axial-flow hydrocyclone is found and explored. • The self-rotation speed can be mainly controlled by the inlet flowrate and vortex finder. • The further activation of catalyst particles is realized by swirling self-rotation. In the process of biomass pyrolysis oils hydrogenation in the ebullated bed, the catalyst faces several serious issues (e.g., short operation time, frequent addition, massive waste) due to coking and channel blocking. Based on the phenomenon of the self-rotation of particles in the rotation shear flow, an axial-flow hydrocyclone is developed to activate the catalyst. In this study, the self-rotation of particles was presented with the help of microfluidic technology and high-speed photogrammetry, and the effect of self-rotation on the deoiling efficiency of the catalysts was investigated using a catalyst activation cold model experiment. The results show that when the inlet flow rate Q and the vortex finder length h c increase, the self-rotation speed of the particles also increases. When the particles rotate, the periodic coupling centrifugal force causes interfacial turbulence between the oil attachments and the fluid, which promotes the mass transfer. When Q and h c were 0.22 m3/h and 335 mm, the self-rotation speed reaches the maximum, which is 887.4 rad/min, the content of guaiacol (coking precursor) decreases from 55.0% to 11.4%, and the content of n-Hexadecane decreases from 38.8% to 16.1%. This innovative technic will prolong the lifetime of catalysts used in the ebullated bed reactor and make biomass pyrolysis oils hydrogenation more competitive. [ABSTRACT FROM AUTHOR]