Efficient One-Stage Bio-Oil Upgrading over Sulfided Catalysts

Abstract

Efficient upgrading of fast pyrolysis bio-oils into products that can be easily integrated into existing refinery complexes remains to be a challenge particularly from the stability of a catalyst performance point of view. Several NiMo catalysts, mainly alumina-supported, were either prepared or acquired and used in hydrotreating of bio-oil from ablative fast pyrolysis of straw. The experiments were carried out in a fixed-bed reactor at 340 °C and 4 MPa and lasted for 80 h. Detailed monitoring of the key physicochemical properties allowed comparing the performance of the catalysts and assessing its changes with the time-on-stream (TOS). The quality of all products deteriorated with the increasing TOS evidencing gradual loss of performance. Nonetheless, the product quality over the best catalysts remained suitable for further refinery upgrading by coprocessing during the 80-h TOS. Distillation of a hydrotreated bio-oil into naphtha, gas oil, and atmospheric residue allowed obtaining further insights into oxygenates present and their distribution.