Process for treating crude oil using hydrogen in a special unit

A process for treating crude oil or partially upgraded crude oil to reduce viscosity or upgrade such oil using hydrogen treatment under reactive conditions, said process comprising:

• i) heating feed stream of crude oil to about 38° C. to about 316° C. and introducing to said feed stream a first heated side stream containing hydrogen, and mixing said feed and side streams to produce a mixed stream having uniform dispersion of hydrogen molecules in said mixed stream;
• ii) dividing said mixed stream into a minor mixed stream and a major mixed stream, introducing said minor mixed stream to a primary separating vessel to achieve separation of volatile light ends from hydrotreated heavier ends;
• iii) introducing to said major mixed stream, prior to entry into said primary vessel, a mixed heavy stream returned from a primary hydrogen treatment zone to quench hydrogen treatment and minimize coke production in said primary vessel;
• iv) removing volatiles from said primary vessel and directing them to a secondary vessel for further separation;
• v) removing heavy non-volatiles from said primary vessel and directing said heavy non-volatiles to a primary hydrogen treatment loop where a second heated side stream containing hydrogen is introduced and mixed into said heavy non-volatiles to produce said mixed heavy stream, said mixed heavy stream being heated to an elevated temperature of about 343° C. to about 510° C. followed by additional mixing to enhance hydrogen reactions;
• and
• vi) combining said mixed heavy stream with said major mixed stream prior to entry into said primary vessel to quench any coke forming reactions before introduction to said primary vessel.