When I was growing up, diesel was always considered the greener option than petrol, and this was reflected in the prices, diesel always cost less because it was taxed at a lower rate.
Now they say it’s worse than petrol and prices are now higher for diesel.
So what changed, or what did we suddenly learn about diesel that we didn’t know before?
Bonus question, considering they’re both made from crude oil, what’s the difference in how they’re refined?
In: Chemistry
Diesel and gasoline are both products of fractional distillation of crude oil. Crude oil is a huge mishmash of different compounds formed when underground when algae and plankton were buried underground and pressurized. All these different compounds behave slightly differently. One of these different behaviors is their boiling points. Fractional distillation takes advantage of this by heating up the oil to different temperatures to capture what boils at each temperature. A distillation column can do this continuously, by having “stages” at varying heights that are heated to different temperatures in a gradient. So at each “stage,” you may have a different product.
At the lowest stages (the ones that don’t boil or boil only at very high temperatures), you have tar- and asphalt-type compounds. Higher up, you get bunker fuel, which is fuel oil for ships and heaters. Higher than that, you get diesel and mineral oils. Higher than that is kerosene, jet fuel, and gasoline, and so on. So they come from the same material, but they are different (although pretty similar) parts of that original material.
Latest Answers