The Evolution of Gasoline
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Published 2023-04-22
Gasoline is a mixture of light hydrocarbons with relatively low boiling points that, at the time, had no significant commercial value and was even seen as dangerous, due to its high volatility. Because of this, It was initially considered a waste product and was often discarded and simply burned off.
COMPOSITION OF GASOLINE
Despite its public perception, gasoline is not a clearly defined compound but rather a homogenous blend of light to medium molecular weight hydrocarbons. The hydrocarbon types that commonly combine to form gasoline and contribute to its properties as a fuel, are paraffins, olefins, naphthene, and aromatics. Depending on the blend, gasoline can vary anywhere from 32 to 36 megajoules per liter.
EARLY GASOLINE
Early gasoline produced directly from distillation was known as straight-run gasoline. When gasoline containing sulfur is burned are a major contributor to smog, acid rain, and ground-level ozone. These early gasoline blends, by today’s standards would be unusable in the higher compression engines of today as even the most high-test blends would have an octane ratings below 70, with lesser quality blends going as low as 40.
CRACKING
By 1910, the rising demand for automobiles combined with the expansion of electrification, created a flip in the product demands of the petroleum industry, with the need for gasoline now beginning to supersede that of kerosene. Coined the Burton process, this technique thermally decomposes straight-run gasoline and heavier oils, cracking the heavier hydrocarbons and depleting their hydrogen to produce more lighter hydrogen rich hydrocarbons. The instability of fuel was also a concern, as the higher levels of unsaturated hydrocarbons produced by thermal cracking were reactive and prone to combining with impurities, resulting in gumming, further exacerbating the problem.
CATALYTIC CRACKING
In early 1920s, Almer McDuffie McAfee would develop a new refining process that could potentially triple the gasoline yielded from crude oil by existing distillation methods. Known as catalytic cracking, the process heats heavy hydrocarbon feedstock to a high temperature along with a catalyst in a reactor. The catalyst initiates a series of chemical reactions that break the hydrocarbon molecules apart into smaller fragments that are then further cracked and recombined to produce lighter, more desired hydrocarbons for gasoline.
Catalytic cracked gasoline had a significantly higher olefin content, and more branched-chain and aromatic hydrocarbons than thermally cracked gasoline, which raised its octane rating. The catalyzing action also produced a fuel with lower sulfur and nitrogen content, which results in lower emissions when burned in engines.
FLUID-CRACKING
In an attempt to circumvent Houndry patents, Standard Oil began researching an alternative method to catalytic cracking, resulting in the development and fielding of the fluid based catalytic cracking process in the early 1940s. As the catalyst becomes deactivated by build up of carbon deposits caused by the cracking process, the spent catalyst is separated from the cracked hydrocarbon products and sent to a regeneration unit.
HYDRO CRACKING
During this time period, a new type of catalytic cracking process based on decades of research on hydrogenation, a reaction where hydrogen was used to break down large hydrocarbon molecules into smaller ones while adding hydrogen atoms to the resulting molecules. Its efficiency at producing higher yields of gasoline from heavier oil products led to it being adopted on a commercial scale by refineries around the world during the 1960s.
POST LEAD
After the phase-out of lead additives in gasoline, the petroleum industry switched to MTBE. MTBE in particular. This phase out of MTBE led to ethanol becoming the primary oxygenate and octane booster in gasoline by the early 2000s.
ALKYLATION
Beyond additives the process of alkylation also grew in its use to boost octane-ratings. This technique is used to produce alkylates, a high-octane blending component for gasoline. Much like other catalytic process, The acid catalyst is separated and recycled, while the alkylates are separated and unreacted isobutane recycled. The high-octane alkylate is then blended with other gasoline components.
ISOMERIZATION
Another similarly catalytic technique that began to grow in popularity is gasoline isomerization. This process typically focuses on the conversion of low-octane straight-chain paraffins found in light naphtha into branched-chain hydrocarbons that have a higher octane rating.
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All Comments (21)
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I own a chemistry book from the 1930's that spoke of the use of lead in gas. It straight up said the lead put into the air was statistically insignificant... To be fair, this was when uranium glass was also a thing
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Why do you only have 537K subscribers?!? You consistently out-perform the production quality of big-ass media corporations. No thundering sensationalisation. No shallow scripting that assumes the audience is denser than lead. No nauseating flashing animations to make the obvious even more obvious. Only clean well scripted narration at precisely the right pace to keep me interested but without spilling into "yapping". Only professional grade animation that focuses on what is important to what is being said. And absolutely no "I'm scared of scientific words"-dumbing down of the subject matter. THANK YOU!
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I must say that I have extensive knowledge in the petroleum refining process and you absolutely knocked it out of the park with this video. You covered a huge amount of knowledge in this 27 minute video ❤
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12:00 My dad was an oil refinery technician in the 70's, 80's and a bit of the 90's. He was also a GA pilot and owned a 1/4 interest in a Cessna 177 Cardinal RG. He had a friend who's sone was in a high security juvenal prison in central California and every month would fly the friend and his wife down to visit their son. Like many planes the Cardinal leaked a bit of oil which would end up streaked along the belly of the plane. Once while waiting for his friend to finish his visit he took a rag put some of the high lead 100 octane aviation gasoline onto a rag and cleaned the oil off the belly of the plane. For work he was required to have his lead levels tested and one such test came up the day after this visit. His lead levels were dangerously high, just from handling that gasoline covered rag. Tetraethyl lead was some really nasty stuff, and the Ethel Corporation did everything it could to hide this fact.
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Something that's worth noting -- General Aviation aircraft in America STILL use leaded fuels to this day! It's actually legally mandated by the FAA, too, since unleaded fuels are still seen as experimental for GA aircraft! There are a few experimental GA aircraft that can use unleaded fuels, but they're incredibly uncommon. Absolutely amazing video!!!
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Shukov was 1891, not in 1981 ;) (switched the 8&9 I assume)
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Wow, tetra ethyl lead was like a high speed catalyst. I never thought about it that way. Great way to illustrate the process.
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Ethanol in gasoline has provided me with a steady supply of lawnmowers that would no longer run. Clean the carb. (sometimes a cheap new carb, , fresh gas. It's back in business. Now those EPA gas cans.... that's another story, I've split and wasted more with those things then I ever did with the old ones.
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Here is another tidbit I picked up while working in the business of installing gas station equipment - The mid-grade blend is actually mixed at the proportional valves at the dispenser itself. Most stations only get two products (liquid gasoline) delivered. The octane blend of the mid-grade is set by a programmable ratio for different state requirements. Most tanks only contain either low-grade or high-grade. I said "Gas Dispenser" because they are NOT pumps. The pumps are STP's that are actually submerged in the tanks underground. There are precious few "actual" pumps above ground unless the tank happens to be above ground.
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Excellent and highly informative. My only problem -- and it's serious -- is the casual, utterly nonchalant vague mention at 22:36 of the use of biomass having an effect on food prices. The effect on Mexico alone is stunning: a price increase of only 20%results in 14% additional costs for that 80% of their staple grain (maize/corn) before inflation. According to a Tufts paper 10 years ago, some 40% of food production had already been reallocated to ethanol. Not only have food prices since the major shift toward biofuel skyrocketed, the production receives government subsidies, meaning it's not even paying its own way while increase. Along with removing food, there's the soil depletion, made worse by attempts to use the cellulose from the non-food portion of the corn plants for fuel as well.
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I remember the filling station asking "Leaded or unleaded regular?" in the mid 70s as it was being phased out, both simultaneously existed at the filling station for a bit of time.
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Cool video. I was a technician for BP Chemicals. Lubricating oil and fuel development. We also did independent engine testing.
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Sir, you make some of the best content on Youtube. Nothing else to say.
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Piston aviation engines do not use high compression ratios. They're in fact quite low by modern standards with the highest certified engine having only a 8.7:1 compression ratio. The reason for the high octane is mostly due to fixed timing using magnetos out of 1930s tractors. All the higher horsepower engines are also air cooled and have terrible combustion chamber design, last being updated in the 1960s. Hot spots, lead fouling. One manufacturer finally got around to rollers and sodium filled valves in the 2000s, a cool 50 years later than cars.
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22:25 There are also concern about land management. Corn, one of the most popular plants for ethanol production depletes the ground of nitrogen and a lack of crop rotation leads to heavy use of ammonia to keep the land viable to growing more corn.
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I absolutely love all your videos. I could listen to you narrate all day long ❤
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Lead in fuel also lubricated the valvetrain. I had to knock back the timing in my classic to prevent the heads getting too hot and damage to the valve seats. Either that or I have to put in additives, which can get expensive.
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Beside the OCTANE Rating, this fantastic Video would be great to include the KWh/l and per Galon to generate a general understanding on the evolutional power density. Also the Carnoute principle to understand transformation limits would be a great edit, as well as the general final energy use. Outstanding Video great job.
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top quality, very informative, easy to consume content. you are the type youtube needs more of :)
