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Comment by thereisnospork | Hacker News Reader

As a rule, it is far easier* to transport/handle liquids in large quantity than solids. Even ignoring the effort to convert/deconvert the oil at each end, I'm not seeing this as a step forward that will improve the bulk of crude-oil transport -- baring a more detailed analysis than what reads to me as 'pipelines bad.'

*Cheaper, safer, more efficient, requiring less maintenance, etc...

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> As a rule, it is far easier to transport/handle liquids in large quantity than solids.*

Is it?

For liquids, at all times you need a sealed container that doesn't leak. For solids, it's enough for the holes to be no larger than the individual solid object. This makes containers cheaper and requiring much less maintenance.

As for this specific case, the article makes at least two points:

- transporting solids can reuse existing infrastructure (rail + coal wagons), giving you flexibility - as opposed to requiring you to ship from only where the pipeline ends (or to build new pipelines);

- with "one weird trick" (injecting some extra gas into the bubble) they can make each pellet buoyant, and it seems they also don't dissolve easily - the result is something that's potentially much easier to collect if you happened to spill it into an ocean.

They wouldn't build pipelines in the first place if it didn't make business sense to do so. These pipes will be in place for a very long time (relatively speaking). I would also think that railroad or road for transporting a solid liquid is also less environmentally friendly than sending via pipelines. Of course, if you are assuming that the pipeline will burst, then it may not be, but one has to ensure that the pipeline is a safe option. Government oversight is needed in those cases.

I understand the argument from the article is about flexibility - a pipeline will be in place for a very long time, but it's not easy to move it around as the economical landscape changes. Meanwhile, rail will let you move the stuff to wherever it's currently better to have it.

-> "they can make each pellet buoyant, and it seems they also don't dissolve easily"

damn that would definitely help on spill cleanings!

Is bitumen a liquid or a solid? Technically, you can argue for either, but practically it seems to be very much a solid.

Is water a liquid or a solid?

It's a pretty simple question to answer if you know all of the parameters of the environment.

Not given "all the parameters of the environment" it is common to assume STP: Standard Temperature and Pressure. I think that's 20 degrees Celsius, 105 kPa of air pressure.

Well, under those conditions I would call bitumen a 'semi solid'. It is not hard in the sense of an actual solid, you can deform it but it definitely does not flow like a liquid.

That's a viscoplastic. Banana, chocolate, and dog droppings are some common examples.

Thank you for that term, I didn't realize there was an appropriate word to describe that state.

AFAIU, it's a liquid, and it does flow, it's just that it flows so slowly it's almost impossible to notice

https://en.wikipedia.org/wiki/Pitch_drop_experiment

Actually bitumen does flow. It's an extremely viscous liquid. There are a couple of pitch drop experiments[1] running, where bitumen is placed in a funnel and allowed to slowly flow. The experiment at the University of Queensland opened the funnel in 1930, 9 drops have flowed out since then, the last in 2014. The period between drops after air conditioning was installed seems to be in the 12-14 year range (only 2 drops have happened in that period).

[1] https://en.wikipedia.org/wiki/Pitch_drop_experiment

That's super interesting. I wonder if a vortex (a very very slow one) forms in the pitch in the upper container.

No, there is too much frictional loss.

The raw material isn't a liquid that can be pumped. This approach is converting the raw material into pellets instead of diluting it into a liquid, which is the current approach.

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