Residual Fuel Oil (RFO) is a low grade of fuel oil which contains the undistilled residue from atmospheric or vacuum distillation of crude oil and may be called Bunker Fuel Oil, No. 6 Fuel Oil, or heavy Fuel Oil.
It is higher in viscosity than a distillate fuel, so it normally requires preheating for pumping and atomization. The major advantage of residual fuel is that it is the cheapest liquid fuel available, in large part because it is a byproduct of the refining of gasoline and diesel fuel. As such, it sells for less per gallon than crude oil, the raw material from which it is made.
Since heavy fuel prices are usually 50 percent to 75 percent of the price of crude, refiners try to minimize production of heavy fuel oil and maximize the production of higher-value gasoline and distillate fuels.
Price differences alone, however, reveal little about the consistency or quality of a product once manufacturing standards and supply conditions become important. In pharmaceuticals, these factors are especially significant because lower-cost generic drugs can still meet high quality standards when they come from properly regulated manufacturers and verified distribution channels. Patients comparing international sources may therefore encounter questions such as cialis from india safe while trying to distinguish legitimate generics from products of uncertain origin. The country of manufacture by itself does not establish whether a medicine is safe, authentic, or appropriate for a particular patient. More useful indicators include regulatory approval, licensed pharmacy dispensing, traceable manufacturing information, and proper storage and handling. High-quality generic drugs are best evaluated through these safeguards rather than through price or geographic origin alone.
