The Alchemists

How oil built the world

The device you hold, the clothes you wear and the food you eat owe thanks to wizards: People who sniffed the heavy odours of crude oil and hallucinated an entire world in their image.

You live in a world of oil.

This is no slight to you, either: Oil has a bad name, but has bequeathed wonder on our world. Nothing you do would be possible without the petroleum pioneers: The men of heat and vapour, of pipework and process, condensate and coke.

When we glimpse an oil refinery, perhaps in passing by car or plane, perhaps on TV or a Google search, we blank out the sprawling chaos and dragon-breath exhalation. All we know is that here is something ugly, so we tune it out.

Ugly? Maybe. Vital? Certainly.

A modern refinery is an artifact of such colossal complexity that it seems like magic. The mazework of piping, Reaction vessels, valves, pumps, condensers… a working refinery has a spark of the divine, as if life breathes in the giant distillators. An odd sort of life, brief-lived and born in heat from the fossil oil.

Modern refineries give us every sort of chemical under the sun, along with many more that never see it. It's not an exaggeration to say that the heart of our civilization beats in this industrial maze.

But they weren't always so complex, and oil wasn't always so omnipresent. By starting at the very beginning and working through the evolution of this fantastic beast, we can start to understand some of the complexity before us, and where it came from.

Want to learn more?

1: Lamplight and the death of whales.

Light was expensive once. If you wanted to see indoors past the hours of sunset, you had to be a rich man. Guttering candles twitched and puttered, illuminating houses by throwing men’s shadows afore them. Candles are expensive luxuries, and a chandelier, plus the staff to keep it lit, was a beacon of status and sickening wealth. Walls and ceilings would accumulate the smoke of burnt wax & tallow over the years.

Oil lamps democratised this to some extent, but there's oil and then there's oil. The good stuff, with the cleanest smells and least smoke came not from the ground but from whales: Regular whale oil was obtained by rending down blubber. At its peak in the mid 19th century, whale oil imports to the United States amassed 10 million gallons of whale oil, as well as 5 million gallons of sperm oil, which was the really good stuff. Sperm oil, a sort of wax, was obtained from the spermaceti organ of the sperm whale, inside the big bulging blockish head where the animal produces powerful sonar pulses. Unlike regular whale oil, which while preferable to crude from the ground still burned with a strong odour, sperm oil burned with a clean, odourless flame: The perfect light for the gentry.

This all changed with a man called Samuel M. Kier of Pennsylvania, USA, who was the first to figure out how to refine crude oil into more useful things. Samuel, a serial entrepreneur, ran a salt production facility, and was frustrated by oil fouling his salt wells. He initially dumped it, but after one of the dumped slicks caught fire he started investigating how to distill and make use of the otherwise useless substance. Initial forays into oil-based medicine and petroleum jelly came to nothing, but he then discovered that distillation would allow him to produce clean-burning kerosene from worthless crude.

Kerosene was known about at the time but had not been commercially exploited, as whale oil was cheap and readily available. This started to change in the latter half of the century and Samuel developed the world's first commercial oil refinery to produce and sell ‘carbon oil’, a form of Kerosene, for illumination. He even produced new designs of lamp to better make use of the product.

To explain this, first we need to understand what oil is. It's not a single chemical but a solution of hundreds of different chemicals called hydrocarbon polymers; long chain molecules that are mostly made up of hydrogen and carbon, hence the name. A lot of the useful properties of these chemicals are defined by the length of these polymer chains and, usefully, so is the boiling point.

And this means that you can separate them by condensing oil vapour at different temperatures.

Here is a simple kettle still for batch-based oil distilling. It wouldn't be much different from Samuel Kier's own design, and comprises a coal furnace which heats a still into which oil is pumped under pressure. All but the heaviest fractions of this oil boil and pass through a condensor tower, where temperature of the vapour gradually reduces with height. The lighter fractions condense further up, the heavier ones further down, and are returned to the still. The lightest of all escape through the top as a vapour, where they enter a condensor where cooling water forces condensation into liquid.

This can be further separated by pressure: The condensed vapour is still under pressure, due to both from the initial pumping pressure and the energy added by the furnace. Because boiling point also changes with pressure this allows the gas & condensate mix to be split again, with the gas burned off and kerosene retained.

More advanced versions of the batch still refining process would be developed over the decades. For example, in the version above, many decades after Samuel Kier's designs, further pressure separators are added, plus a thermal cracking loop. The high pressure separators pick out the super-light and volatile hydrogen, methane and ethane gases, while the low pressure separators split ethane & propane gas from gasoline & kerosene liquid.

Very interestingly, this design also features tubes for tar efflux that will not boil in the still and leaves through the bottom. Instead of being directly collected, however, these tubes pass adjacent to the coal furnace, where the intense heat thermally ‘cracks’ the heavy fractions into lighter ones by breaking the molecular chains into shorter ones. That lets the heavy stuff have a chance at another run through the system.

This is a bit more advanced than Samuel Kier's original design, but picks up on a few subjects we'll be covering as we go through the development of the refinery: Fractional Distillation, separation by pressure and thermal cracking.

But demand was increasing and society was changing. Refining had created something new: Cleaner heat, cleaner light and a growing list of petroleum-based products, industrial and personal. And as demand surged, so did the volumes required of refineries. Samuel hadn't patented his innovations, and while that didn't stop him becoming a very rich man, it did enable a horde of copycats. Refining became global, and competitive.

The new industry needed to keep the oil flowing…

2: Keeping it flowing: Continuous distillation.

Batch processing, as pioneered by Kier, had made sense, but as the industry grew its inefficiencies became obvious: Time is wasted cleaning residues between batches, and while it's possible to have larger batches that also means longer heating times, which is its own marker of inefficiency. Longer, hotter heating in big batches also promotes oil degradation and coking problems at the heating interface: Batches, clearly, have their own lose-lose limitations.

The answer, developed from 1880, was continuous fractionation. Multiple stills are used, with each filling into a fractionating tower and looping liquid residues back in. Because multiple towers and stills are available, it's no longer necessary to completely finish processing on the first before adding new oil, so a continuous feed becomes possible. 

Of course, since short chain molecules and volatiles, with their lower boiling points, will mostly be removed in the very first still & tower, subsequent stills and towers can be primed for higher temperatures and boiling points to make best use of them.

Now let's increase the complexity a little…

So far, we've looked at fairly simple fractionating columns, with a single distillate output leaving the column at the top, and a thick liquid bottoms fraction at the bottom, but they can be a lot fancier than that. As any high school chemistry student can attend, -if they were paying attention-, a fractionating column can tap product at many levels simultaneously, split by boiling point and the height along the column that they condense at. This means lots of bubble trays to be sure that you're separating precisely, and lots of vertical height to ensure that the temperature difference between tap-off points is aggressive enough to ensure effective separation.

And this means that fractionating columns for refineries, and chemical plants, can get complex and big. Really, really big!

So our refinery is starting to get more complex, but this is just the start. You're in for a wild ride over the ever-changing contours of refining temperature and pressure.

And pressure can go down as well as up. Let's cover vacuum distillation…

3: Don't sweat the heavy stuff: Vacuum Distillation.

Kerosene is lovely stuff: It heats homes and illuminates the dark. It can power machinery too, but machines need something else that refining can provide.

Lubrication.

The heavy ends of the refining process are worth paying attention to as well. Shoving Them all into the barrel marked ‘tar’ means ignoring a lot of gorgeous, gooey goodness held inside, which would be perfect for lubrication.

The problem is that heavy ends tend to have boiling points of over 400 celsius at ambient pressure, and heating them past this risks thermal cracking and solid residue that needs cleaning off. 

But recall that you can play with pressure as well as temperature…

Reduce pressure and you reduce boiling point too. A vacuum distillation unit processes the heavy ends by drastically reducing the static pressure in the system so that they can be boiled and separated in the usual manner. 

Now, when processing in noxious, hot, reactive environments you can't easily use regular vacuum pumps, and the volume flow you need in oil distillation is massive, so we need to generate very low pressure some other way. The answer is by using a steam ejector.

A steam ejector uses high pressure steam to create a low-pressure suction zone. Confused? A pressure differential between the high pressure steam and the outside world sets up a high speed flow, and this is accelerated even further with a venturi, a pinched tube that hugely accelerates the fluid running through the constriction in order to keep mass flow constant.

Now, in an accelerating, non-compressible fluid the total pressure remains constant. The total pressure is made up of the static pressure and the dynamic pressure. The dynamic pressure varies with velocity squared, so shoot up velocity and static pressure drops. Drop it enough and at the pinch point of your steam ejector a powerful suction force is generated which can depressurize your vacuum distillation unit 

Easy-peasy!

So we can distillation heavy ends into lubrication oils now as well, brilliant!

But while all this was happening and the 19th century ticked into the 20th, the world was changing. Three innovations in particular were about to change the world of light & motion, and of refining, forever.

The electric lightbulb.

The aeroplane.

The motorcar.

Refining changed the world. Now the world changes refining…

4: Motion for the masses!

The democratisation of light.

The electric light bulb did more than illuminate. It changed time itself.

Under the stained yellow gaze of the electric bulb a factory could run at all hours. Shops & surgeries could push back the advance of evening under the cold warmth of the carbon filament, while parents read their children bedtime stories to the un-flickering light of the future.

The Edisonian light bulb was followed in 1903 by a second foreshadowing of what would become the new American century. Fitfully, wings warping and humming to the rhythm of a basic 12 horsepower engine, the Wright brothers took their creation to the air over Kitty Hawk, North Carolina. Their flyer covered only 32 metres on its inaugural journey and would fly only four times in total, but the brothers had changed history.

The third gateway to the new century was flung open in 1908 by the Ford Model T, as trailblazing industrialist Henry Ford brought his universal car to the masses.

These three innovations from the United States would transform and remake the world, simultaneously shrinking geography as they expanded time itself.

And they would also remake refining. The kerosene lamps of yesteryear would go, just as the expansion of the motorcar and new roads & suburbs birthed something new and invigorating.

The age of kerosene was over. The century of gasoline had arrived!

The thermal refinery was created to leverage the thirst for gasoline by exploiting a process called thermal cracking. When long chain hydrocarbons are exposed to very high temperatures and pressures they can break into shorter length hydrocarbons, in a semi-random process. Because many of the characteristics of hydrocarbon chemicals, such as volatility and boiling point, are defined in part by their molecular chain length, this allows a refinery to convert heavy, long-chain oil fractions into more useful short chain ones.

Like gasoline.

The temperatures & pressures required by thermal cracking are high: Between 450 and 750 celsius and anywhere up to 70 atmospheres of pressure. This is not a process for the faint hearted… but then, that's refining for you.

The first few decades of the twentieth century were tumultuous, riven by war, mechanised slaughter, global plague, euphoria and then global depression. The alliances of old were tested, wrought, broken. Staggering into the late 30s, it would have been reasonable to conclude that the worst years of the twentieth century had passed. Surely our quota for bad luck and human avarice had been reached? Could we finally relax?

We could not.

After a period of steady armament and encroaching industrialization of the new means of war, Hitler's tanks swept into Poland on September 1st, 1939. 

The next few years would see the horrors of World War 2, industrial warfare and the growth of the catalytic refinery.

5: World War & the Catalytic Refinery.

In many ways the world wars were the wars of the chemists, and refining was no exception.

One of many fronts in the evolving conflict was the horsepower war on land, sea and especially in the air, where each side strove to outdo the other for competitive battlefield advantage. 

One manifestation of this was the need for higher octane fuels, resistant to auto-ignition at high pressure and so usable in high performance aero engines.

High octane fuel fractions were a useful side effect of the catalytic refining revolution, where a catalyst drastically reduced the heat & pressure requirements for cracking heavy fractions into lighter ones, and enabling easier mass customization of fuels as a result.

The catalyst typically targets the hydrogen bonds in a hydrocarbon chain, stripping a hydrogen atom and so making it easier for cracking to occur. The interaction also forms a positively charged ion, and this then goes onto interact and ionize other polymers in turn, so the effect moves through the solution long after the catalyst has knocked over the first domino.

What has this to do with high octane fuels? Well, catalytic cracking creates more branched molecules than thermal cracking, and these polymer branches have the side-effect of making fuels derived from this more resistant to auto-ignition at high pressure.

In short: Catalytic cracking helps to create high octane fuels, which in turn allow higher pressure ratios in engines, which in turn allows higher efficiency and specific power.

And so as Messerschmitts and Focke-Wulfs chased Spitfires and Mustangs in the skies over Europe and Africa with ever more highly aspirated supercharged engines, two secret wars were being fought: A secret horsepower war in the air, fuelled by a secret war of the chemists on land.

It gets better still, of course. Early catalytic crackers used solid beds of catalyst that would have to be periodically cleaned or regenerated: A nuisance. Fluidic catalytic cracking was developed, where the catalyst is introduced as a powder into fast moving vaporised hydrocarbon feed in a riser, becoming fluidized. Cracking occurs within seconds, but then the catalyst needs to be separated and regenerated, so cyclonic separators strip the now-coked catalyst powder and sends it into a regenerator loop. In the regenerator, air inflow ignites the coke, regenerates the catalyst and loops it back, while the hot flue gas drives a turbine that powers the compressor to provide the air supply in the first place.

Got all that? Good, because that's the simple version. A fluidized catalytic cracker, unlike its primitive predecessors, can run continuously for up to 3-5 years between scheduled shutdowns.

On such things are world wars fought.

And as the war drew to a close, the spillover from all of this innovation would accelerate the civilian world as well. The age of gasoline and precise fuel formulations, the age of plastics and tailored chemical feedstock for all kinds of new industries…

The dawning of the cold war was also the dawn of a new consumer golden age, and a renewed optimism in our gleaming technological future.

Powered by oil.

6: Beating scarcity: The heavy ends conversion refinery 

A spanner in the works.

In 1973 the Yom Kippur war pitted Israel against a coalition of Arab states, and the Israeli victory led the Arab members of OPEC, the petroleum exporting cartel, to lash out against the United States and supporters of Israel. This lashing-out came in the form of an oil sanction that flicked the global economy and Western diplomacy into a flat spin.

But the Alchemists of Oil were ready to respond. 

The Heavy Ends Conversion Refinery was born from the oil shock, when the constraint on supplies of light crude, plus spiking prices, made unconventional refining processes valuable.

Finding diamonds in muck.

Earlier on when we discussed the first batch-based refineries we outlined the danger of raising temperatures too high for too long on the batch vessel. This is to prevent coking of the oil, which is the accumulation of nasty solid carbon deposits, but in the Heavy Ends Conversion Refinery we want to do that!

Coke, by the way, is also what you get when you heat coal in the absence of air. It's a little bit weird that a coal derivative can sit in the middle of an oil refinery that has no access to coal, but there you go.

In the most brutal refinery thermal process, two huge coking drums, mysteriously topped with drill derricks, stand like totems. One is always busy, the other resting. This unusual tag team run an endurance event to convert the heaviest tarry goop that even vacuum distillation has been unable to bring around.

The bottoms from vacuum distillation is run at up to several bar through a furnace heat exchanger to bring it up to 475 celsius. It's mixed with steam to prevent early coking in the heat exchanger and is then introduced into one of the two coking drums.

The vacuum fractionator must work continuously, so heavy product is fed into the coker for 16 to 18 hours, a marathon of a process where thermal cracking opens up the heavy fractions into lighter elements and coking strips the surplus carbon, which is deposited thickly inside the drum. The hot gaseous output of the Coker is fed back to the vacuum fractionator, where it is quenched by the fractionator's own inflow to prevent coking from occurring where it shouldn't. This cyclic process then gives us our best hope at recovering useful chemicals from heavy tarry oils.

In such ways did the world pass through the 1970s oil crisis and out the other side, and this gave birth to other benefits: Once refineries were equipped for the heavy stuff they could then make better use of thick Venezuelan and Canadian oil, among others.

While one drum is busy coking, the other needs to be cleaned: A rig above it drops a drill down into the coke, then hydro cutters are engaged to further break it up. In this way the drum is painstakingly cleansed and flushed, ready to go again. The upstream fractionator can't stop and must keep on going, and because coking is a batch process this is why you need two drums, one to coke and one to clean. A perfect tag team.

It also means that somewhere in the middle of a heavy ends conversion refinery, someone is drilling for coal… or something a lot like it, which is just bizarre.

Another heavy ends process, which can run alternately or in place of coking, is Visbreaking. Essentially Visbreaking is a milder thermal cracking treatment that won't reduce all heavy oils like coking, but also minimises coke formation. Hence the refinery can gauge itself to the output required: If heavy oils are still in demand, lean towards visbreaking. If not, or if coke products can be sold, then go all the way to the thermal rigours of coking.

Our refinery is now getting complex, and the range of product is becoming truly broad, from asphalt to fuel gas and everything in-between.

And remember that when we started, with Samuel Kier and his brine wells, all that he was getting was kerosene. 

Look at us now!

But it gets even better…

7: Crude, chemicals & carbon: Refining without the guilt.

Refining is a work of magic, no doubt. From a gloopy mess pulled from the Earth we've achieved riches and incredible variety. We live now in a petrochemical world, living off petrochem fertilizers & food, wearing petrochem clothes and fighting off the winter with petrochemical energy. Every aspect of our society has been turbocharged, elevated and made better by this bounty from below.

But alas there is a catch.

Refining is a brutally energy intensive process. High pressures and intense heat means that about 5% of our crude is burnt just to provide heat to refine the other 95%: A colossal, and polluting, waste. Refining makes up 4% of all mankind's CO2 emissions, almost double that of aviation.

Can we improve this: Enjoy the riches without the drawbacks? Get the gilt without the guilt?

Maybe.

Heat recovery can only get you so far, but last year in an obscure Chinese city called Rongcheng, a new type of super-safe and super-hot nuclear reactor, the HTR-PM, went critical for the first time. There's an article on it below, but this could be part of the answer to the question of how to make the alchemy of refining a little bit cleaner.

Why not supply process heat with the power of the atom instead?

In our new era, where the Climate Calculus is made to filter every decision, this has a certain appeal, if you can just get past the presence of a nuclear reactor: Statistically it'd probably be the safest bit of the refinery anyhow.

But the world is warming and there's pressure everywhere to reduce emissions: What use is it, you may ask, in cleaning up refining when most of the product is fossil fuel? There's no point virtue signalling by refining with nuclear process heat or green electricity if the refined fuel you make is just going to be burned somewhere else.

Enter the crude-to-chemicals refinery.

It's merely a concept so far, but you can polymerize fuels as well as crack them, so in principle you can orient an entire refinery away from fuel and towards plastics and chemicals instead. Do this and, if you're heating with clean power, you can give birth to the most unholy creation of all…

A clean oil refinery!

Well, clean-ish.

There is a music to history, and through the 20th century the Alchemists of Oil danced with the world to this slow waltz.

Sometimes the world leads the refineries. Sometimes refineries lead the world.

The Alchemist’s creations change over time, bringing new bounties from base oil, because the beat always changes.

But the music never stops.