and a constant reducing atmosphere is maintained by the addition of hydrogen line 65 excess hydrogen may be removed by bleed stream 50 the catalyst slurry is recycled back to upgrading reactor 10 as needed through line 30 recycle makes up can be as high as 95 wt of the catalyst used in the upgrading reactor the catalyst activity is maintained by running the upgrading process at 100 conversion maintaining an at least minimum reducing atmosphere throughout the upgrading separation and storage and not allowing the catalyst composition to settle at any time following the separation in the hot high pressure separator there is no need for further separation steps throughout the process substantial temperature and pressure fluctuations are tolerated with only minor precipitate formation of supercondensates and coke in past processes in which recycle has been employed the slurry catalyst composition has sustained substantial fouling and deactivation for the first stage operation as depicted in upgrading reactor 10 the temperatures for heavy oil feedstocks are normally above about 700 u00b0 f preferably above 750 u00b0 f and most preferably above 800 u00b0 f in order to achieve high conversion hydrogen partial pressures range from 350 to 4500 psi and hydrogen to oil ratio is from 500 to 10 000 scfb the concentration of the active slurry catalyst in the heavy oil is normally from about 100 to 20 000 ppm expressed as weight of metal molybdenum to weight of heavy oil feedstock typically higher catalyst to oil ratio will give higher.