The PJ Tatler

Arabian Alchemy: Shell makes black gold in Qatar

PJ contributor Leon de Winter mailed us an article from The Volkskrant, which Leon calls the New York Times of the Netherlands (which seems damning with faint praise to me, but never mind that).  The title of the article is (roughly) “Shell’s magic makes black gold from natural gas.” Frustratingly, I can’t get the Volksrant website to deliver me a link to the original article, but I was able to find it on Lexis, and between my small ability to read Dutch (see, you learn how the Dutch spell things, then read it out loud — if you speak both English and German, you can make sense of it) and Google Translate, I was able to get the gist.

And it’s a pretty interesting gist, I’ll tell you what.

Here’s the basic story: In a June 4th story, Michael Persson reports that the first product is coming from the Shell-Qatari joint project a half-hour out of Doha. The project is called “Pearl” and its function is to transform natural gas into synthetic replacements for petroleum products. In other words, turning natural gas into oil.

Conceptually the process is simple. Natural crude oil is a mix of a variety of hydrocarbons, which of course are simply molecules made of hydrogen and carbon. (This is distinct from carbohydrates like sugar, which also include oxygen.) A lot of the hydrocarbons in crude oil are long chains — they have many carbon atoms joined together. When crude oil is refined, the refinery basically does two things: first, it separates out any naturally-occurring shorter chains, which includes things like pentane, hexane, heptane, and octane. We call a misture of those things (and some other stuff, this is a bit oversimplified) “gasoline.” This isn’t sufficient to provide as much gasoline as we’d like, so a catalytic process is used to convert other fractions into the right components for gasoline. Natural crude usually contains some other compounds, like sulfur compounds. When you hear the TV business people talk about “sweet crude”, they mean crude with relatively little sulfer. “Sour” crude, naturally, has more sulfur. The sulfur compounds have some commercial uses, but they present processing problems, so “sour” crude is less desirable” than “sweet” crude.

The effect is that long-chain hydrocarbons are broken down into shorter chains; this process naturally releases some energy, so it’s “downhill”.

What Shell is doing, through a process called GTL (“gas to liquid”, aren’t scientists just poets?), is running a refinery backwards. Natural gas is primarily methane, the simplest hydrocarbon; the GTL process pushes it back up the hill to form longer hydrocarbon chains. This process consumes some energy, so it’s a little bit counter-intuitive why you’d want to do such a thing, but there are some real advantages. First off, natural gas is hard to handle — you can’t run a pipeline across the Pacific, and storing it in tankers means either storing it under very great pressure, or cooling it to very low temperatures to make it a liquid.

Longer chain hydrocarbons naturally have a higher boiling point, so they’re easier to keep liquid, easier to store in tanks. Years of transporting liquified natural gas in large quantities have proven that the whole effort is an expensive pain in the — expensive pain.

What’s much more important about the synthetic long-chain hydrocarbons from the Pearl operation is that they are very much like gasoline, diesel fuel, and kerosene (jet fuel.) Since they’re being built-to-order, so to speak, they have an advantage over conventional fuels too — they’re much purer. Natural gas is perfectly “sweet” — in fact, a sulfur compound, ethyl mercaptan, is added artificially to give it the “smell of gas”. Otherwise, natural gas would be odorless. The GTL process produces synthetic longer-chain hydrocarbons that never had the odd sulfur compound, or aldehydes and ketones (more smelly stuff) to be removed.

One result is a fuel like diesel fuel, that can be used without engine changes in a conventional diesel engine, but that produces cleaner exhaust, little or no soot, and is much less smelly. Changing the process lightly creates something very much like gasoline; a slightly different change creates something like kerosene.

The other result is this: we have lots of natural gas, throughout the world and in the USA in particular. Hydraulic fracturing — “fracking” — has opened up amazing reserves that weren’t thought to be practical a few years ago.The discovery of immense clathrate deposits — so called “burning ice” — are another immense source of natural gas. (In fact, the estimates right now are that clathrate deposits are the equivalent of twice all other other fossil fuels on Earth.) And perhaps best of all, the current costs of transporting natural gas are high enough that many refineries and oil fields simply flare off — burn — waste natural gas.

The gas-to-liquid process makes all those sources available not just to generate power and heat, but to replace fuel oils, and even lubrication oils. The combination of natural gas production and GTL technology could conceivably replace the whole expensive infrastructure required to move oilgas from the Middle East to Europe and the Americas, and make “waste” natural gas into a commercially useful product. As long as the price is right.

That’s the literal bottom line to the GTL process: it appears that the Shell process, as it stands right now, is financially feasible if the price of oil exceeds $20 a barrel.