A BEST-KEPT SECRET OF WWII
There was a military secret that gave the Allies a significant advantage in winning World War II.
To give it a sense of scale, let me talk a little about the chemistry of crude oil. My simplistic explanation comes mainly from an article at AmericanHeritage.com.
When “up from the ground comes a bubbling crude” (go ahead, hum the theme to The Beverly Hillbillies), it isn’t good for much. Crude oil is a mixture of thousands of differently sized hydrocarbons and has significant impurities. There are straight-chain hydrocarbon combinations, with carbon atoms attached in a row; branched combinations, with carbons splitting off at one or more junction points, like tree branches; and others are cyclic, repeating various combinations of carbon atoms.
Summarizing, crude oil contains a series of progressively heavier compounds, ranging from light gasses (like natural gas) to heavy viscous tarry asphalts (like the oil used in asphalt and roofing tar), all related to the number of carbon atoms in the compound. A common way of describing the compounds is how they react when heat is applied, called their boiling point. That is, at what temperature does a particular hydrocarbon go from a liquid to a vapor?
For example, gasoline vaporizes at from 86 to 428 degrees Fahrenheit, while kerosene needs from 356 to 752 degrees, lubricants above 662 degrees, while waxes and asphalts vaporize at even higher temperatures.
This is all good if you want to separate crude oil into more refined products. Simplistically, you heat up crude oil to the gasoline temperature range, the gasoline hydrocarbons “boil off”, you collect them, cool them back to a liquid, and you have gasoline. From the same batch, you increase the temperature for kerosene, boil it off, collect and cool it, then increase the temperature of the batch again for lubricants, and then heat it even more for asphalts.
However, you can only get out whatever is already there, so, around 1900, a barrel of crude oil was typically about 60% kerosene, which was naturally abundant, with the remainder split evenly between fuel oil, gasoline, and other products. Any natural gas was considered a nuisance and was burned off, while gasoline, which was viewed as being too volatile to be much good, was often dumped in a nearby river.
That was the early days, when kerosene was used as a fuel for lamps. However, Henry Ford introduced the Model T in 1908, and by 1910, there were 500,000 automobiles on the road burning gasoline. Between 1911 and 1912 alone, the sales of gasoline went up 80%. All the oil refiners were desperate for ways to get more gasoline from a barrel of crude.
Okay, hold that thought.
Another descriptor used for gasoline is its “octane” level. In a gasoline engine’s cylinder, a piston compresses a mixture of fuel vapors and air, which is then ignited by a spark from a spark plug. The resulting explosion pushes the piston back out again, sending power through a drive train that eventually turns the wheels. If there’s not enough octane in the gasoline, the compression alone is enough to ignite the vapor prematurely, before the piston has gotten to its greatest height in the piston, and there are then two explosions, one by compression and one by the spark plug.
This is a big problem for a gasoline engine and will eventually, as you might imagine, cause it to break itself. This double explosion is called “knocking”. I remember listening to a car engine that had a “knocking” sound. Adjusting the timing belt usually solved the problem.
It was decided to give any particular combination of gasoline an octane number that varied from 0 (which described straight-chain n-heptane, which produced knocking in virtually any engine) and 100, which described a combination that was the least knock-prone). So, when you fill up next time and notice that the gas pump offers you gasoline with different octane numbers (84, 87, 91, for example), you should use the one recommended for your vehicle because the engine has been designed and tuned for that particular fuel mix to maximize the height of the piston in the cylinder before the vapor is ignited.
For all of you who own diesel pickups or RVs, the octane rating for diesel is 20 to 40, which explodes under compression easy enough that you don’t even need a spark plug for ignition. Diesel is also much less likely to catch fire, which is why diesel is used on ships and trains.
Okay, back to history.
By the end of the 1920s, after a series of advances in the refinement of crude oil, typical gasoline yields were higher than 40 percent and with a base octane rating of 60. The major advance was the development of “cracking”, which broke up higher combinations of carbon atoms into simpler combinations. They then added stuff to it to bring the octane rating up into the 70 range. One of the additives they used was lead.
In 1922, a young Frenchman named Eugene Houdry was a mechanical engineer in France. While visiting the United States, he became fascinated with race car driving. Returning home, he bought his own Bugatti and drove it around in his free time. France, at that time, had no oil reserves; they got their crude from Iraq. Houdry saw a demonstration of a sample of local coal that had been passed through a catalyst to produce a high-octane gasoline. When he put it in his Bugatti, it ran like a bat out of hell. Houdry smelled not only a high-grade gasoline from the process, but also high-grade money: France had a lot of coal, so Houdry formed a company to industrialize the process that produced the gasoline.
To make a long story short, the gasoline-from-coal business floundered, but Houdry transformed his company from being a producer of gasoline to that of being a developer of the catalyst used in the process, as well as owner of the process itself. After considerable effort, he found itself a partner, Sun Oil Company, in America to help test out the process that used his catalyst.
It took Houdry several iterations over the next decade to find the perfect catalyst, but by 1937, received a patent number 2,078,945 for an aluminasulfate catalyst that had the color of well-chewed chewing gum and was extruded in the shape of macaroni. With more development, he and his partners built a processing unit for Sun Oil that took the leftover sludge at the bottom of a distillation tower and produced an 81-octane gasoline, and that was without any additives, at all. Using a catalyst in combination with “cracking” revolutionized the petroleum industry.
Why is all this important?
When Germany invaded Poland in 1939, and then went to war with Britain, the most common fuel used in fighter planes and bombers was 87-octane gasoline. When America started the lend-lease program, and then joined the war, it was already using 100-octane aviation fuel in its aircraft. It had gotten there by repeatedly using the Houdry process. By the time America introduced the P-51 fighter, it was using 130-octane gasoline. Both the process and the fuel itself had been declared military secrets.
When the British used 100-octane aviation fuel in their Spitfires and Halifaxes, it made the planes 34 miles per hour faster at 10,000 feet. They were now faster than the Luftwaffe, surprising the Germans to no end. Additionally, the improvement in the quality of fuel produced by the Houdry process made the need to replace engines decrease from every 500 hours of operation to 1000 hours of operation, and reduced the cost of British aircraft by 300 Pounds Sterling. For a four-engine bomber, that was a significant cost reduction.
The Germans, the Japanese, and the Russians, never discovered that America and Eugene Houdry had re-invented gasoline to help win the war. Houdry was satisfied with his contribution to the war effort and in 1950, formed a company to reduce automobile emissions that he believed were causing an increase in lung cancer. He invented the first catalytic converter, but was too far ahead of his time to make a profit from it.
He died in 1962.
11/14/2021 11:10:52 pm
Thanks for the info. Most of that I knew, but it is good to see it all laid out in a coherent manner.
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Don Willerton has been a reader all his life and yearns to write words like the authors he has read. He's working hard at it and invites others to share their experiences.