Something about oil refining?

i have always been curious about oil refineries. We all know that distillation towers use temperature differences to separate crude oil into its respective constituents, but where does all that energy come from? does it come from oil itself? In the end, are we just burning oil to refine oil?Something about oil refining?
Essentially, yes.





The source of heat needed for all sorts of refinery operations, not just distillation, depends on the process and how the plant is designed.





Some use electricity, some use natural gas; it's common for leftover waste products from refining to be burned for heat, like process gas or petroleum coke. It's also common to use rejected heat in the form of steam to run other processes.





But, the bottom line is, refining oil ends up burning yet more fossil fuels.





There is a term in engineering called ';Energy Returned On Energy Investment';, or EROEI, sometimes called ';EROI';





EROEI = net energy produced / energy sources consumed





In practice this is hard to measure or even estimate, if you include all the energy spent on extracting, pre-refining, pumping, shipping, and trucking the finished product to gas stations. It also depends a lot on the quality of the crude oil and the final grade of gasoline....





I've heard it quoted from anywhere from 20:1 to 2.5:1. I can't find many good sources


http://i-r-squared.blogspot.com/2008/11/鈥?/a>





... In the case of 2.5:1, for example; that means that the energy equivalent of 1 gallon of gasoline must be burned to produce 2.5 gallons of ';juice';, from a total input of 3.5 gallons of crude.





~just a few thoughts....Something about oil refining?
Any heat source can be used in the furnace to distill oil, but I would suspect that the least expensive are used, probably coal or oil.