Tuesday, March 29, 2016

PST gets it wrong (Dilbit vs "Crude")

Re: this post by PST to facebook:


QUOTE: As of today it's been three years since crude oil flowed through the neighborhood in Mayflower Arkansas. Has there been any meaningful change? Still no better leak detection, still no automated valve requirements, still no verification of the fitness of old pipelines, still no better spill planning, still no one looking at health effects. ENDQUOTE

No, it wasn't "crude oil", it was Dilbit, "Diluted Bitumen". There are very important distinctions. While many in the mainstream media got this wrong, PST should know better and should be reporting this correctly so the people can be informed.

What is being mined in Alberta Tar Sands IS NOT OIL. It is not anything like you grandfather's "crude", which is a complex mixture of a broad spectrum of hydrocarbons, from the lightest (methane, ethane, propane, butane), to the mids (kerosene, pentane, decane), to heavy oils (fuel oil, lubricating grease, waxes), to the heaviest (asphalt, tar, bitumen, pitch).

No, what they are mining is a very low-grade hydrocarbon, bitumen, which can be considered equivalent to the heaviest fractions of crude oil. Bitumen in raw form is a semi-solid like coal, and smashes with a hammer when struck. No one would look at a chunk of bitumen and think of it as "oil", which denotes a slippery liquid.

Bitumen/asphalt/pitch/tar is such a low-grade product, it was considered refinery waste. On many old refinery diagrams it is called "residuum" or "bottom's product". It is literally the dregs of hydrocarbons.

Now even this low grade substance can be chemically smashed at extremely high energy levels, broken down into smaller-chain hydrocarbons, and then recombined and fractionated into refined products. However, this can only be done, at great expense and energy inputs, at a very few refineries which have been specially equipped.
I have not found proper estimates of the EROEI (net energy returned on net energy invested) for e.g. gasoline made from Dilbit, but it is very low, approximating 1:1.  

Not only that, but the environmental costs of mining and refining bitumen are extremely high. The Alberta scar on the ancient Boreal Forest, including tailing ponds hundreds of square miles, is so large, you can see it from space. There are also the "Great Sulfur Pyramids", which are as large as the pyramids of Egypt.

Raw bitumen cannot be shipped in a pipeline. So the industry came up with is to dilute it with condensate, aka, Natural Gas Liquids (some of the lightest hydrocarbons), hence "Dilbit".

Again, Dilbit is chemically very different from natural crude oil, and must be shipped to special refineries via pipeline or rail.

Dilbit pipelines have failed, both in Canada and the US at very high rates. So much so that there have been studies commissioned to see if it is more corrosive than traditional crude.

Dilbit spills are extraordinarily difficult to clean up, since when it hits water, it separates. The NGLs float, and the bitumen sinks.

Dilbit transportation  is also regulated differently, since Dilbit IS NOT crude, it is exempt from a tax levied on crude oil that is used to clean up spills.

All of these points are important for people to understand, since Dilbit is (last checked) now around 15% of all US refinery inputs, and growing.

If people understand all of this, they might ask the question: Why is it that 15% of all refined products begins as a low-grade hydrocarbon dregs, which can only be transformed into refined products at extremely high costs,  in every sense: in terms of capital costs, energy inputs, and environmental costs?

So I hope PST corrects this very serious error. Thanks.


May you, and all beings
be happy and free from suffering :)
-- ancient Buddhist Prayer (Metta)

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