Crude oil is initially treated in a desalter unit where excess salts, mud and water are removed. It is then processed through a single-stage atmospheric pipe-still or APS (fractional distillation column). Fractional distillation uses the difference in boiling point to separate the hydrocarbons in crude oil into different cuts/streams. The APS produces an overhead naphtha cut, kerosene and gas oil sidestream cuts and a bottoms stream at 650 degrees F (See Figure 1). Variations in the draw-off temperature used for the sidestream cut produces kerosene or aviation fuel and auto diesel or marine diesel in blocked operations.
The naphta cut is de-ethanized, debutanized and split with light, middle and heavy virgin naphthas to blend motor gasoline. A portion of the heavy virgin naphtha (HVN) is also blended to middle distillates and heavy fuel oil (HFO). The middle virgin naphtha is fed to the reforming unit where it undergoes a process by which low octane number straight-run naphtha is upgraded to a higher-octane motor fuel blending grade by catalytically promoting specific groups of chemical reactions. The reformer is a semi-regenerative type catalyst system. The grades of gasoline made by the refinery include both 87 and 90 Octane Index.
Light end fractionalization splits into propane and butane which is used as liquefied petroleum gases, (LPG) or blended in the gasoline pool (butane). The kerosene sidestream is hydrofined to ensure suphur and nitrogen targets are met and then run down to tankage as dual purpose kero/turbo fuel. Auto diesel oil is produced by blending a part, or all of the kerosene sidestream to the gas oil stream. It is also hydrofined (treated with hydrogen over a catalyst to reduce sulphur and nitrogen content) to meet sulphur specifications and then sent to storage. On occasion however, it may also be run down directly to tankage as Marine gas oil (MGO), which is a heavier cut gas oil from the atmospheric distillation unit.
|UNITS||EQUIPMENT $ CAPACITY B/CD|
|Gas Oil Hydrofiner||7,200|
Light Ends Fractionation
|Virgin Naphtha Splitter||5,400|
Products from the Refining Process
- LPG / Petroleum gas – used for heating, cooking, making plastics small alkanes (1 to 4 carbon atoms), commonly known as methane, ethane, propane, butane
- Naphtha or Ligroin – intermediate that will be further processed to make gasoline mix of 5 to 9 carbon atom alkanes
- Gasoline – motor fuel mix of alkanes and cycloalkanes (5 to 12 carbon atoms)
- Kerosene – fuel for jet engines and tractors; starting material for making other products mix of alkanes (10 to 18 carbons) and aromatics
- Gas oil or Diesel distillate – used for diesel fuel and heating oil; starting material for making other products
- alkanes containing 12 or more carbon atoms
- Heavy gas or Fuel oil – used for industrial fuel; starting material for making other
- long chain (20 to 70 carbon atoms) alkanes, cycloalkanes, aromatics
- Residuals – coke, asphalt, tar, waxes; starting material for making other products
- multiple-ringed compounds with 70 or more carbon atoms
- Ultra Low Sulphur Diesel (ULSD)