Process for hydrotreating biomass oil diluted in a refinery stream of petroleum hydrocarbons

A process for hydrotreating biomass oil diluted in a refinery stream of petroleum hydrocarbons, the process comprising processing the biomass oil diluted in a refinery stream of petroleum hydrocarbons in the sulphided catalytic beds consisting

• of (i) a first monometallic catalytic bed containing only one VIB metal oxide and (ii) at least one second bimetallic catalytic bed for hydrotreating the refinery stream, the process comprising the steps of:
• (a) diluting a volume of biomass oil comprising more than 70% by wt of one or more triglycerides and/or one ore more fatty acids in a refinery stream of petroleum hydrocarbons with a distillation range between 140 and 500° C. to obtain a feedstock containing between 1 and 75% by wt of the biomass oil;
• (b) mixing a hydrogen stream with the feedstock to obtain a first reaction mixture, which is heated and injected in the first catalytic bed at a temperature of between 220 and 370° C., causing it to react under a pressure of between 3 and 15 MPa;
• (c) injecting upstream of a second catalytic bed a dilution stream comprising hydrogen to obtain a second reaction mixture, which is hydrotreated under conditions for hydrotreating petroleum hydrocarbons, such that gaseous products and a stream of liquid hydrocarbons are obtained;
• and
• (d) separating the gaseous products, recovering a stream of liquid hydrocarbons containing dissolved gases, and purifying the stream to remove dissolved gases to obtain a hydrotreated liquid product.