U.S. Emerald does not engage in the refinery process, but since it may be of interest, we have included a diagram and some discussion of this process. The source of this information is the Encyclopedia Britannica.
Petroleum is refined to make gasoline and other petroleum products from crude oil. Fractional distillation of heated crude oil starts the process. Components of the crude oil – including gasoline, naphtha, kerosene, light gas oils, heavy gas oils, and residuum – are divided up into light and heavy hydrocarbons. At lower temperatures, Light Hydrocarbons are drawn off the distilling column easier than heavy hydrocarbons. Then, the components are treated in several different ways, depending on the preferred final products (shown at the bottom). The conversion processes (shown as blue boxes) are discussed in the article. To simplify, not all of the production conversion processes are revealed in the diagram.