FUEL OIL, generally obtained from the bottom cut of distillation tower-residue. Because the sulfur contained in the crude oil is concentrated in the residue material, fuel oil sulfur levels are naturally high.. The sulfur level is not critical to the combustion process as long as the flue gases do not impinge on cool surfaces (which could lead to corrosion by the condensation of acidic sulfur trioxide). However, in order to reduce air pollution, most industrialized countries now restrict the sulfur content of fuel oils. Such regulation has led to the construction of residual desulfurization units or cokers in refineries that produce these fuels.
Residual fuels may contain large quantities of heavy metals such as nickel and vanadium; these produce ash upon burning and can foul burner systems. Such contaminants are not easily removed and usually lead to lower market prices for fuel oils with high metal contents.
| Test | Method | Unit | Specs |
| Density @ 15 ˚C | ASTM D-1298 | g/m3 | Max 0.991 |
| Kinematic Viscosity @ 50˚C | ASTM D- 445 | cSt | Max 200 |
| Flash Point | ASTM D-93- B | Deg C | Min 60 |
| Water Content | ASTM D-95 | %vol | Max 0.5 |
| Pour Point | ASTM D-97 | Deg C | Max 30 |
| Sulfur Content | ASTM D-4294 | %wt | Max 4 |
| Conradson Carbon Residue | ASTM D-189 | %wt | Max 18 |
| Ash Content | ASTM D-482 | %wt | Max 0.15 |
| Total Sediment Potential | ASTM D-4870-A | %m/m | Max 0.1 |
| METAL | |||
| Zn | IP-470 | PPM | Max 15 |
| Na | IP-470 | PPM | Max 100 |
| Ca | IP-470 | PPM | Max 30 |
| Al+Si | IP-470 | PPM | Max 80 |
| V | IP-470 | PPM | Max 350 |
