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When I worked at Howell-North Books in Berkeley, editing volumes of railroad history and Western Americana, I learned many interesting facts. One was that the word “ore,” from the viewpoint of a miner, has no exact definition. Sure, the general meaning is material that can be mined and refined at a profit. But that doesn’t tell you what percentage of a shovelful of dirt constitutes ore and the rest waste in any particular sense, because the values keep changing based on the methods used and the current state of the market. An independent mercury miner hand-working a seam at the now-defunct New Almaden mine in California might discard any load with less than ten percent cinnabar as waste not worth hauling back up to the surface. The operator of an open-pit, steam-shovel copper mine in Arizona might take two pounds of metal out of a ton of ore—or one percent—and call it a rich mine.1
The same thinking applies to a barrel of oil. There is no standard definition or composition of the commodity we call “oil.” Sure, there are benchmarks for pricing, like “West Texas Intermediate” (WTI) and “Saudi sweet light crude.” But every field produces oil with a different proportion and weight of underlying hydrocarbons. And each refinery is optimized to take oil of a particular quality from a particular region.
I remember when the Trans-Alaska Pipeline was approved, all the oil produced on the North Slope was legislatively earmarked for North American refiners on the basis of “energy independence.” Then the obvious place to ship Alaskan oil was the Chevron refinery in Richmond, California. But that refinery was optimized to take raw product from the fields of Indonesia. This oil from the Far East is more like coke than crude. If you spill it on the water, it doesn’t spread out to form a bright, rainbow sheen; instead, it contracts into floating clumps like bits of cork. So, at the time, a deal was made that allowed North Slope oil to be sent to Japanese refiners, and Japan traded it barrel-for-barrel with the Chevron refinery for their take of Indonesian oil.
When I was at the end of my last freelance, novel-writing gig in the mid-1990s and the money was running out, I needed to get back into the corporate world. The fastest way to build my resumé after such a hiatus was to hire out as a contractor rather than hope to be employed directly. So for a number of years I became a Kelly Temp. I worked for a season as administrative assistant in the Control Systems Engineering Department at Royal Dutch Shell’s refinery in Martinez, California. And as is my practice, I used the opportunity to ask intelligent questions and learn everything I could about the business.2
I can remember as a child, when the family drove from Philadelphia to New York, seeing the oil refineries of New Jersey five or six miles away from the highway across the tidal flats. I can remember smelling them at that distance, too—a rich, funky, sulfurous odor, like a mixture of hot tar, rotten eggs, and farts. So as an adult, when I went to work at Shell, I mentioned to my supervisor that the site didn’t smell like a refinery. He replied that if I ever did smell anything, I should report it, because the company would then pay me $25. “If you can smell something, that means we’re losing product somewhere.”
In the earliest days of refining—oh, late 1800s to early 1900s—the process was pretty simple, based solely on thermal cracking. These people were what modern refiners call “oil boilers.” They would heat the raw crude and feed it into a tower that drew off the fractions—based on the number of carbon atoms in the hydrocarbon chains—that settled out by weight. Lightest, and coming off the top of the tower, were the gases with one, two, three, or four linked carbons surrounded by hydrogen atoms: methane, ethane, propane, and butane. Since most refineries had no large customers for these byproducts and couldn’t be bothered to compress and store them until they collected enough to sell, they just lit a flare at the top of the tower and burned them off. In the middle of the tower came the liquids with between five and sixteen carbons: from pentane to hexadecane, represented by gasoline (octane, eight carbons), kerosene (decane, ten carbons), typical diesel fuel (dodecane, twelve carbons, and heavier fractions), and bunker C fuel oil (pentacontane, about fifty carbon atoms).3 And at the bottom of the tower would be the residues: tars, waxes, and the stuff that is used to make asphalt. Mixed in with the straight-line hydrocarbons chains would be those with odd branches and cross-connections. Along with the oil would come impurities that are not exactly hydrocarbons, like the carbon-ring molecules benzene, toluene, and xylene. You can also find other compounds, like sulfur, which makes the oil categorically “sour.”
Each type of crude oil yields varying fractions of these products. You can guess that “sweet light crude” has only small amounts of sulfur and large fractions of the liquids useful in blending gasoline, kerosene—once a lantern fuel but now burned in jet engines—and diesel fuel. You can also guess that heavy, sludgy oils, like that from the Indonesian fields, contain a lot of tar and wax.
In the old days, the refiners took what they could get from the oil by fractionation. The 42 gallons in a standard barrel might, in a really good grade of crude, yield only twenty or thirty gallons of highly prized gasoline, and the rest would go to less valuable byproducts. And of course, the gaseous fractions were still flared off as waste. This explains why oil prices are pegged to benchmarks with known qualities. The quoted price per barrel is always adjusted locally for the grade of oil and its fractions.
But that was the old days. In a modern refinery, like the one I worked at in Martinez, the operation uses all the fractions. The operation is more than just a cracking tower; it’s a complete chemical plant. After the cracking step, the gases, the lightest liquid fractions, the branched hydrocarbons, and the carbon rings are all broken into simpler, straight-line molecules and then knit back together into gasoline, jet fuel, or whatever the plant wants to make. The heaviest fractions are broken into lighter molecules and then knit together into more valuable products. As the American meatpackers used to say, “We use every part of the pig but the squeal.” And then the modern refiners blend for the designated octane level4 and put in additives for engine cleaning, anti-knock performance, and environmental protection—these days including a percentage of corn-based ethanol—in keeping with federal and state regulations.5
If you drive by a modern refinery, you may still see clouds of white stuff coming out of pipes and boiling off some of the buildings. These days, that’s just steam venting from a heating process or condensing out of a cooling tower. Most refineries still maintain a flare, but it is not part of regular operations and is used only in emergencies. No matter how safe and well run a modern refinery may be, the various processes are still handling volatile, flammable products at high temperatures. Sometimes a batch deviates from its nominal operating parameters and might explode or burn, injuring personnel and damaging the plant. In that case, the control system automatically dumps the batch down a pipe that leads to a nozzle far off in the middle of a gravel field. There the product can be mixed with air and burn away without endangering anyone.6
So that’s my trip down memory lane. Oil is a fascinating and complicated business. And, like almost every other industry, the state of the art is constantly evolving toward greater efficiency, lower costs, lower environmental impacts, and greater dependability. This is a good time to be alive.
1. And when I worked at Kaiser Engineers in Oakland, we produced a massive, twelve-volume engineering report on an iron-ore mine in Ivory Coast. This was to be a vast complex on new ground, with an open-pit hematite mine, mill and slurry plant, pipeline to take the slurry to the coast, pelletizing plant to turn the ore into shippable form, stockpile and ship-loading facilities, and a new harbor, plus housing and amenities for all the workers. The proposed ore was rich, 42 percent pure iron. But because the mine was 400 miles from the coast, most of that through treacherous mangrove swamp, and the cost of money was high at the time, while the world market for iron was weak, the partners simply could not justify building the plant. All that glitters is not gold, especially when it’s on the backside of the Moon.
2. Part of my weekly duties was to back up Control Systems Engineering’s computer records. Although the hardware and software that ran the plant were modern and up-to-date, the backup system was a relic from the old IBM 360 days. So I learned to mount, feed, and start reels of nine-track magnetic tape—those big cabinets with spinning reels and loops of tape that spelled “computer” on the television shows I grew up with in the 1960s.
3. Generally, the fewer carbons there are in the chain, the more thoroughly the fuel burns—that is, breaking more of the available carbon-to-carbon bonds at once—leaving fewer unburned hydrocarbons to flush out as soot and particulate. This is why methane burns more cleanly and with higher energy than gasoline, and much more cleanly than lump or even powdered coal.
4. When I worked at Shell, the Control Systems engineers told me a dirty little secret: that they sometimes had difficulty making fine adjustments in blending the octane level; so their medium and premium grades of gasoline always carried a few percent more octane than was strictly required by law. So if you care about your engine’s performance, go to the big yellow seashell sign. (But, then, maybe they grinningly tell that to all the newbies.)
5. California has its own mix of additives, required by the California Air Resources Board (CARB). That’s why the world can be awash in oil and gasoline, but if there’s been a fire or other shutdown at a California refinery, supplies will be tight and the price will go up.
6. The flare went off once when I was on the Shell property. It wasn’t an accident; one of the engineers was testing a new way to ignite the errant product stream more efficiently. The blast and roar shook the surrounding buildings.