Making petrol from air
I’VE no idea whether this is just a spoof story that’s been fed to the Telegraph or whether there really are some people sufficiently deluded to think that this is a good idea. But there’s a story today that you can make petrol from air. And this is how you do it:
A small company in the north of England has developed the “air capture” technology to create synthetic petrol using only air and electricity.
Experts tonight hailed the astonishing breakthrough as a potential “game-changer” in the battle against climate change and a saviour for the world’s energy crisis.
The technology, presented to a London engineering conference this week, removes carbon dioxide from the atmosphere.
The “petrol from air” technology involves taking sodium hydroxide and mixing it with carbon dioxide before “electrolysing” the sodium carbonate that it produces to form pure carbon dioxide.
Hydrogen is then produced by electrolysing water vapour captured with a dehumidifier.
The company, Air Fuel Syndication, then uses the carbon dioxide and hydrogen to produce methanol which in turn is passed through a gasoline fuel reactor, creating petrol.
The chemistry can be done: that’s not the problem at all. But you’d have to be certifiably insane to do it the way that it is described here.
You can most certainly use carbon dioxide and hydrogen to produce methanol. But why bother? Why not grow some barley, make methanol (or ethanol) the normal way we do for beer and booze and then make the petrol?
You can certainly electrolyse hydrogen from water but why then make methanol (or petrol) from it? You can run hydrogen through a fuel cell anyway.
Using sodium hydroxide to make pure carbon dioxide is well known. That’s what it’s for, to make pure rather than the not pure stuff you can get out of the atmosphere.
But here’s the really insane part. The production of sodium hydroxide is a hugely energy intensive process. Billions of kWatt hours are used to do this each year. And one by product of the process is chlorine: so, what are we going to do with all of that? Another byproduct is hydrogen: so what the hell are they doing electrolysing water to get hydrogen for? I actually know (as in, work with) a factory that makes sodium hydroxide and they’re always trying to work out what to do with the spare hydrogen they create.
And finally, the idea that it would just be lovely if we powered all of this by solar cells. The energy requirements of this tortuous process are such that it would be vastly cheaper to stick a battery in a car and use the solar cells to power that. Or even to let the sunlight grow the crops which make the methanol.
I still don’t know whether this is a spoof or madness: but either way it ain’t ever gonna work.
Posted: 20th, October 2012 | In: Money, Technology Comment (1) | TrackBack | Permalink
