How does Refinery Work
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Let’s make some money! The easiest place to start is at the top of the steel in a simple refinery and work our way down as before the overhead can go to fuel for the furnace next we take the gasoline stream from the steel which is pretty low octane and the molecules are pretty small with a catalytic process called power forming we can do two things that you see here we pull off hydrogen and use that later to help remove sulfur and there is only new molecules or a collection of very high-octane gasoline we also make feedstock for chemicals called aromatics they are separated eventually to make products like fibers and beer bottles which is always a good thing next let’s go to the bottom of the steel and look at the mixture called fuel oil which isn’t worth much but it still has a lot of good molecules stuck in there and if we’re going to be profitable we have to figure out how to get them out the first step in the next diagram is to add another pipe steel the one that runs with a vacuum at less than normal air pressure what that low-pressure does is allow us to lower the temperature that the fuel will boil without becoming tar and just like in the first still we now have a light oil or gas oil a medium oil or Lube oil and a very very heavy fuel oil generally we need to take the sulfur out of these streams but we can do that by using another catalytic process and the rest of the hydrogen from the power former so our picture is getting complicated but we’re increasing value every step of the way the light gas oil can go to a process called catalytic cracking or simply cat cracking there’s that word catalyst again in this diagram you can see that at high temperature and with that catalyst the gas oil breaks down mostly into gasoline and heating oil along with a chemical feed called propylene which eventually becomes a plastic these are our high-value products the medium gas oil can also go to the cracker but if you choose the right crude oil it turns out it can be purified and makes lubricants that are worth more than gasoline the next diagram shows a finishing block for lube oils here sulfur and waxy material are removed during finishing some material is rejected and provides additional feed for a tech cracking the purification steps in the finishing block are complicated we don’t need to know the details now lastly in the diagram we still have a very heavy fuel oil and we have several options the molecules boil too close together to distill this mixture we can sell it as fuel oil by blending in a small amount of light material but we can also use a solvent that separates even more oil from cat cracking from the very heavy stream the rest becomes Road asphalt we also have a process called coking which is very intensive and expensive and it gets even more oil out and leaves a solid like charcoal called coke. coke is a very fine fuel when you need extreme heat such as in a mill and make steam our simple refinery struggled to make money this high conversion refinery does better because it separates every molecule to its highest value in use the downside is that it’s very investment intensive taking billions of dollars and requires a lot of technology sometimes also map mammoth equipment and a lot of people to operate and maintain it and smart engineers to optimize it there are other processes we didn’t talk about that have names like isomerization alkylation and hydro cracking that make it even more intense that and increase the quantity and quality of gasoline many refineries process 200-300 even 500 thousand barrels of crude oil every day they work on very slim margins but because they choose the right crude for their facilities configuration and upgrade every molecule they can survive the last overlay shows the addition of chemicals processing steps to further improve profitability we separate and recover aromatics from gasoline we convert heating oil and sometimes lighter feed like ethane from gas plants in steam cracking to what are called basic chemicals they become plastics fibers and rubber among other things that process operates at very high temperature to crack material and very cold temperatures to separate the products.