Studying the Effect of the Process Temperature on the Degree of Bio-Oil Hydrotreatment at Low Hydrogen Contents over NiCu-SiO2 Catalyst with a High Metal Loading

The hydrotreatment of pyrolysis bio-oil by hydrodeoxygenation at 6.0 MPa initial hydrogen pressure in the temperature range of 150-350 degrees C and the presence of a NiCu-SiO2 catalyst synthesized using the sol-gel method is studied. The stability of the catalyst including the agglomeration of active component particles and the deposition of carbon on its surface is also investigated. It is shown that the content of oxygen in the products of the hydrotreatment of lignocellulose pyrolysis liquid decreases from 37 to 15 wt % upon an increase in the process temperature. Using a CHNS-O-analyzer, it is established that the amount of coke on the catalyst's surfaces at a temperature of 350 degrees C decreases by 4 times, compared with that formed at 150 degrees C. X-ray diffraction shows that increasing the process temperature results in the gradual agglomeration of particles with a subsequent reduction in their size at high temperatures due to the dissolution of active catalyst components in the reaction medium.