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How an oil refinery works

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Re: How an oil refinery works

#71

Post by deepsun »

sushibowl wrote: post #68
didgetmaster wrote: post #61

I remember driving by a refinery years ago and it had two or three towers with big flames that were just burning off waste gas. This seemed wasteful to me. If it can burn, then it seems like it could be used for something productive. Do they still just burn off that gas?

Usually, when refineries flare something like that it's because what they are burning is not suitable for use, and making it suitable would cost more than the product would sell for. Often methane as a by-product of oil production is flared, because the amount is small enough that it's not worth setting up processing plants and supply chains for. Other times, the fluid is heavily contaminated by e.g. sulfur compounds…

That's why plastic bags are so cheap -- ethanol is a byproduct, but you earn more if you discard it and sell only oil.

But the burned up ethanol would be perfectly suitable for products.

Nowadays there are some regulations to prevent that, so they may sell up ethanol at negative prices sometimes.

UPDATE: Ethene, not ethanol.

Re: How an oil refinery works

#72

Post by cucumber3732842 »

vel0city wrote: post #35
cucumber3732842 wrote: post #31

Earlier quoted context omitted.

"It's impossible to get permission to build something with specifications that is financially viable." There, better? These agencies have all sorts of discretion to waive this or enforce that or interpret some third thing and yet they leverage all of it in a manner that stalls progress. I know a guy who has a textbook perfect situation for a septic in MN. MN won't permit it not because of some law or rule or code, bu…

You mean to tell me the land of 10,000 lakes might have a shallow water table that might require mounds more often to prevent people poisoning groundwater with their literal shit? The horror. Without hard data about the site I'm probably going to side with the county on that one. As for your friend wanting to improve the lot but needs to do a lot of drainage fixes, he should lobby his community for property tax abate…

This sort of surface level ivory tower "nothing that proclaims to be positive for the environment" attitude underpins so, so much of the bullshit that makes us all poorer and worse off.

>You mean to tell me the land of 10,000 lakes might have a shallow water table that might require mounds more often to prevent people poisoning groundwater with their literal shit? The horror.

The "land of 10k lakes" doesn't get it's water from the ground like a desert municipality. They have surface reservoirs and protected watershed areas to keep those clean enough.

The "ground" is effectively the filter. You want it to be full of shit. That's how a septic works. That's how basically all runoff cleansing measures (sand traps, grass buffers, etc, etc) work. You're basically using "nature" as the settling tanks of a water treatment plant. A septic is the same but underground.

The problem is high water table. But as long as the water table permits a septic is great.

>Without hard data about the site I'm probably going to side with the county on that one.

Did you ever think that maybe the reason the dude applied for the septic was because the engineer said "this property is great for a septic, let's do a septic"

Surely this government you think so highly of is capable of exercising judgement.

If not then why give them discretion in the first place?

What about the licensed engineer that must stamp the plans? Surely he is trustworthy? If not then why does the government enforce his license monopoly and force people to do business with him?

>As for your friend wanting to improve the lot but needs to do a lot of drainage fixes, he should lobby his community for property tax abatement to support the drainage improvements

Are you insane or just lying through your teeth. Nobody is gonna add a political advocacy side quest to an already overpriced minor improvement. They'll just bend over and take it and hope to make it up rent or resale.

>It's something we've ignored in a lot of our planning for a long time.

This used to be municipally managed. Landowners built drainage as they saw fit. Municipalities managed stuff like streams and culverts and ditches and whatnot, build flood control dams and holding ponds and the like.

Making it part of the permitting/development process is mostly an exercise in financial engineering (gets the obligation off the municipality) and is worse because you get patchwork of minimum viable solutions (that work poorly) instead of systems that are planned at the municipal or higher level to work well.

>Both of your major examples are probably selfish takes that harm their neighbors to save someone some money.

And peddling things that drive up the viability floor of development so you can feel good about saving the environment isn't.

Enjoy your $3k rent for a 500ft slum. Make sure you complain about "landlords" while you're at it.

You're competing with the person who isn't renting my buddy's ADU because the ADU never happened because the septic upgrade killed it, the minimum viable mound system got put in to save $$ and it has the capacity for the house and nothing more Y'all really served the public interest on that one.

Re: How an oil refinery works

#73

Post by flumpmaster »

jmyeet wrote: post #2

This is a really good overview of oil refining. I'll add a few things. 1. The light and heavy distinction is covered by a measure called API gravity [1]. The higher the API gravity, the lighter the crude; 2. Refiners mix different crude types depending on what kind of refined products they want to produce; 3. Heavy crude tends to be less valuable although it's essential for some applications. Lighter crude produces g…

A few corrections. Credentials: I am a Chemical Engineer in a Senior Tecnical Leadership position at a refinery with over thirty years of experience.

1) API gravity is the density of the crude oil. Higher API = lower density. We use this unit of measure because it magnifies the differences in densities vs. using conventional units of measure.

2) Refiners in the US mix different crude types to maximize the objective function ($) of a set of constraints including crude grade pricing and availability, product demand volume and pricing, refinery unit constraints and product quality specifications. This is done using a linear program model.

3) light and heavy crude contain the same molecules but in different ratios. For example they all contain gasoline, jet fuel, diesel boiling range material and all contain some amount of material that could be turned into ship fuel or asphalt for paving roads. Heavy crude tends to sell at a discount to light crude because of the laws of supply and demand - refiners will buy a mix of whatever makes them the most money.

4) “Most refineries in the US are very old and are very polluting”While US refineries sites are old - some site have been in operation for over 100 year, the units and configuration of the refineries has evolved continuously over the years. The technology used in the refining units has evolved as well - this is not a static industry. The pollution standard for refinery operations and fuel emissions have been raised multiple times. So “Very Polluting” vs. new refineries does not pass muster. US refineries have been retrofitting wet gas scrubbers and selective catalytic reduction units to reduce emissions of SOx and NOx for decades. These technologies reduce emissions of both pollutants by over 90%. Most of the emissions come from burning the fuel that refineries produce and both legacy US refineries and new ones have to meet the same fuel quality specifications and hence produce equivalent emissions.

5. “There are different blends of gasoline that the US produces. The biggest is so-called summer and winter blends. What's the differene? Additives are added to summer blends (in particular) to increase the boiling point so less of the gasoline is in gas form because that produces more smog;”

Summer gasoline contains less butane than winter gasoline. That is the main difference. Butane is added to winter gasoline so cars start in cold weather. There are no additives added to raise the boiling point in summer - just less volatile light material added.

As an aside, Mvodern gasoline vehicles have carbon canisters to capture vapors (such as butane) from the gas tank when not in service. These are then regenerated by sweeping air through them when the vehicles are running.

6. “ California uses their own blends so in 2021-2022 when CA gas went to $8+, it wasn't just "gouging". It doesn't really work that way. CA requires a particular blend that only CA refineries produce so it's simple supply and demand as no new capacity gets added to CA refineries and demand goes up with population growth. The reason for the CA blend goes back to the 80s and 90s when smog was a much bigger problem. Better vehicle emissions standards since then as well as improvements in the blends the rest of the country uses have largely made the CA blend obsolete so CA is really paying $1+/gallon more for literally no reason;”

There is some out of date information here. California is a net importer of gasoline since refinery closures in California have outpaced reduced demand from increased fleet fuel efficiency / BEV adoption. There are refineries in Asia that export California and some other US refineries can also make California grade gasoline but this requires shipping via the Panama Canal on Jones act ships that are scarce and expensive.

P66 / Kinder Morgan are planning a pipeline / pipeline reversal that would bring refined product into California including California gasoline.

Re: How an oil refinery works

#74

Post by sonofhans »

whatever1 wrote: post #33
nerdsniper wrote: post #14

Earlier quoted context omitted.

To me (as someone who has worked on oil rigs, oil pipelines, oil refineries, and chemical plants), crude oil seems far more valuable as a material than as an energy source. It feels like a damned shame that we're still combusting so much of it for heat rather than reserving it for physical materials. I understand the ways that economics are very important, and that the economics still currently favor burning a large…

We can always make polymers and HydroCarbons in general from other sources if we have energy abundance. We literally can just capture the CO2 we emitted from burning fossil and make it plastics. Of course this does not make sense in a world where we do not have enough energy to even keep datacenters open. Edit: To clarify, I do not propose burning fossils to capture CO2 and make plastics. I am a Thermo Laws believer.

That sounds like a hack from late-game Factorio: pollute enough that you can just pull iron filings right out of the air. Everyone wins! Except the meatbags who need to breathe the air …

Re: How an oil refinery works

#75

Post by nayuki »

deepsun wrote: post #71
sushibowl wrote: post #68

Earlier quoted context omitted.

Usually, when refineries flare something like that it's because what they are burning is not suitable for use, and making it suitable would cost more than the product would sell for. Often methane as a by-product of oil production is flared, because the amount is small enough that it's not worth setting up processing plants and supply chains for. Other times, the fluid is heavily contaminated by e.g. sulfur compounds…

That's why plastic bags are so cheap -- ethanol is a byproduct, but you earn more if you discard it and sell only oil. But the burned up ethanol would be perfectly suitable for products. Nowadays there are some regulations to prevent that, so they may sell up ethanol at negative prices sometimes. UPDATE: Ethene, not ethanol.

You wrote ethanol (C₂H₆O), but do you mean ethylene/ethene (C₂H₄)? Polyethylene (PE) is a very common plastic, such as HDPE, LDPE, PET.

Re: How an oil refinery works

#76

Post by beerandt »

sushibowl wrote: post #68
didgetmaster wrote: post #61

I remember driving by a refinery years ago and it had two or three towers with big flames that were just burning off waste gas. This seemed wasteful to me. If it can burn, then it seems like it could be used for something productive. Do they still just burn off that gas?

Usually, when refineries flare something like that it's because what they are burning is not suitable for use, and making it suitable would cost more than the product would sell for. Often methane as a by-product of oil production is flared, because the amount is small enough that it's not worth setting up processing plants and supply chains for. Other times, the fluid is heavily contaminated by e.g. sulfur compounds…

Yea while $ viability is true, it's better to think of as

1) using some potentially useful products as fuel to burning off things you don't want and

2) the buffer to keep non-steady inflows in a suitable ready condition for steady-state processing. (When real world steady-state is less than ideal.)

Number 2 is really what dominates the equation, as shutting in gas sources or even just turning off pipelines is incredibly more complicated than just an 'off' switch.

And turning back on is even more complicated. In the case of wells, once you shut in, turning back on may never result in the same level of production as before.

Re: How an oil refinery works

#77

Post by beerandt »

chasd00 wrote: post #65
didgetmaster wrote: post #61

I remember driving by a refinery years ago and it had two or three towers with big flames that were just burning off waste gas. This seemed wasteful to me. If it can burn, then it seems like it could be used for something productive. Do they still just burn off that gas?

the way it was explained to me is if you see the flares then something is wrong. It may not be catastrophic or anything serious but something isn't going according to plan. Because you're right, why burn it off when you can sell it?

It generally means something is out of balance, which doesn't necessarily mean something is wrong. Usually not.

But if something is wrong, yea you can bet they will be burning off with big flares.

Re: How an oil refinery works

#80

Post by mschuster91 »

dmurray wrote: post #49
throw0101c wrote: post #19

Earlier quoted context omitted.

> It also fails to note that most of the energy ends up us waste heat. I've heard the statistic that 40% of the total oil pumped out of the ground just to transporting oil. We use almost half just to move it to and fro before even using it. Is this accurate?

This can't be accurate. Let's say a barrel of oil travels 15,000 km from Saudi Arabia to Texas, gets refined, gets shipped another 10,000 km to Europe, then the last 1,000 km overland by truck. This reasonably well sourced Reddit post [0] says big oil tankers burn 0.1% of their fuel per 1,000 km, smaller ones a bit more. Say 0.2% on aggregate, that's 5% for the whole journey, 10% because the ship is empty half the ti…

> Say 0.2% on aggregate, that's 5% for the whole journey, 10% because the ship is empty half the time.

Fuel saves from slow steaming and being empty are massive.

> If this were true, even neglecting oil burnt for heating or electricity or aviation, you'd expect 40% of the vehicles to be tanker trucks.

The US has a lot of domestic pipelines [1], and a lot of the remainder is done by train [2] because trains are the most efficient way to transport bulk goods over extremely long distances.

[1] https://www.bts.gov/geography/geospatial-portal/us-petroleum...

[2] https://www.aar.org/wp-content/uploads/2018/07/AAR-US-Rail-C...

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