True, but kerosene happens to be heavier than gasoline, yet lighter than diesel. So from a refining standpoint, it's not too far off from one or the other, which should reduce the cost to produce more kerosene in a refinery that produces both gasoline and diesel (which should just be different distillers in the same refinery).
Aren't refineries specialized to the types of crude (light sweet, versus heavy, versus tar) that they can process? If so, then I think refineries that handle the "domestic sweet light" that's coming out of the permian basin (enabled by fracking) are more likely to be affected as investment dollars dry up.
Or would Canada's Alberta tar sands be impacted first due to their high processing costs and need for high oil prices (which isn't coming back no matter what OPEC does)?
While conceptually true (kerosene sits between gasoline and diesel), that's a high level simplification. Here's an 83 page overview of the refining process
https://nptel.ac.in/content/storage2/courses/103103029/pdf/mod2.pdf
Just reading the first few pages will provide a good overview and some of the different characteristics being tested for.
The two primary characteristics of crude (they even show up in the name) as I understand them:
- light vs. heavy. A measure of the density and/or the fraction of the crude in the longer chain hydrocarbons. Heavy crude has more of the longer chain hydrocarbons. I believe that, everything else being equal, it's easier to get diesel (and kerosene) from heavy crude. Light crude has, on average, shorter chain hydrocarbons, so it's easier to get gasoline (and propane, and the other shorter products).
- sour vs. sweet. A measure of the sulphur content. I don't think it's as simple as "sweet = good; sour = bad", but it is my understanding that there's more refining effort for sour crude, where that effort is devoted to removing, or at least reducing, the sulphur in the crude.
Of course, both of these dimensions are on a continuum - not just two simple binary values.
I have a larger general impression of the refining process is that in theory, you can take just about any crude oil feedstock and get at least some of any product output. And you can combine the intermediate products (and/or finished products) with more processing effort (money) and get other finished products.
However, the more processing you do along the way from crude to finished product, the more equipment and input materials you need (cost / money), and the less economical your refining process will be. This leads to the different equipment optimizations made by different refineries - they design around oil that comes in particular grades, which frequently means particular oil wells and fields, and that gets them their least cost / maximum output refining result.
Which is great as long as the relative economic value of the outputs are reasonably stable relative to each other.
The most extreme version I've heard of - I was reading an article recently about the IMO 2020 changes for the fuel used in shipping. The end result is low sulphur emissions, with 2 approaches to get there. One option is to change from burning bunker fuel (one step or 2 up from asphalt
) to a low sulphur (effectively) diesel. The other option is keep burning the bunker fuel, but add scrubbers that capture the sulphur after the bunker fuel is burned, so that emissions are below the sulphur threshold. (Turns out there are good benefits to going the scrubber route, and the economics are tightly balanced - overall the fleet will do a mix of both).
Anyway - there are a small number of oil wells in the world that produce a low sulphur crude that is close enough to the low sulphur fuel requirements for IMO 2020, that there is a reasonable way to get fuel for your ships - buy the crude from those particular oil wells and burn it directly in your ships. It's about the same as bunker fuel, while having low enough sulphur to pass the new restrictions. Zero refining needed (apparently). Hah! I found an article about this dynamic:
Bloomberg - Are you a robot?
Oh - and I should mention that I'm not a petroleum engineer or even a chemist. I just got interested in the topic by participating in this thread way too much, for way too long. So be sure and chew that salt you're eating this with