One less-explored aspect of the unfolding Colonial Pipeline Co. ransomware disaster is how a single pipe is able to carry premium gasoline and regular gasoline and home heating oil and jet fuel and diesel fuel. You’d think the fuels would mix into an unusable soup, but they don’t. The savings from being able to use one pipe instead of five to carry five types of fuel are enormous.
Colonial’s website has a diagram that explains how it works. Fuels are put into the pipe one at a time. A batch of regular gasoline might come right after a batch of premium. When the fuels come out the end of the pipe and are put into separate storage tanks, the cutover from one tank to the other is staged to protect the quality of the higher-grade product. Premium can’t have any regular gasoline mixed in. On the other hand, it’s all right to have a little premium mixed into the regular. Similarly, home heating oil and jet fuel are similar enough that they tend to be run down the pipe consecutively.