System for producing an american petroleum institute standards group iii base stock from vacuum gas oil

A system for producing an American Petroleum Institute Standards Group III Base Stock from vacuum gas oil, comprising:

• a. a conduit receiving a petroleum derived product having a viscosity index greater than 120, the conduit receiving a vacuum gas oil forming a vacuum gas oil mixture with a combined boiling point range from 450 degrees F. to 1050 degrees Fahrenheit as defined by ASTM D-86;
• b. a first heater fluidly connected to the conduit and to a first hydrogen reactor for increasing temperature of the vacuum gas oil mixture to a temperature from 450 degrees Fahrenheit to 600 degrees F., forming a heated vacuum gas oil mixture.
• c. a pump installed prior to the first heater, a fresh hydrogen injector and a recycle hydrogen injector simultaneously increasing pressure on the heated vacuum gas oil mixture from 50 psig to a pressure from 1000 psig and 1500 psig by injection of hydrogen;
• a plurality of hydrogen reactors connected in series, having a liquid hourly space velocity (LHSV)−1 through the hydrogen reactors from 0.5 to 2.5, for saturating the heated vacuum gas oil mixture forming a first partially saturated heated base oil then a fully saturated heated base oil with hydrogen from the second and third hydrogen reactors;
• e. a high pressure flash drum connected to the plurality of hydrogen reactors connected in series to separate a saturated heated base oil from a recycle overhead at a high pressure from 1000 psig to 1500 psig;
• f. a low pressure flash drum removing contaminants from the saturated heated base oil producing contaminant free saturated heated base oil;
• g. a fractionation tower receives contaminant free saturated heated base oil and steam to remove a light oil fraction with an initial boiling point less than 600 degrees F. while simultaneously refluxing, forming an API Standards Group III Base Stock with less than 0.03 percent sulfur, greater than 90 percent saturates and a viscosity index greater than 120 as defined by ASTM D-2270 and a viscosity range from 2 to 10 centistokes as defined by ASTM D-445 with a boiling range from 600 degrees F. to 1050 degrees F. as defined by ASTM D-86, and a cold crank viscosity (CCS) between 1200 and 5000 centipoise at minus 25 degrees C. and as defined by ASTM D-5293.