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Could diesel made from air help tackle climate change ?
http://www.bbc.co.uk/news/business-34064072

Making diesel out of thin air sounds like something from science fiction. But small companies in Germany and Canada are doing precisely this - capturing carbon dioxide (CO2) and finding ways to sell it. German company Sunfire produced its first batches of so-called e-diesel in April. Federal Minister of Education and Research, Johanna Wanka, put a few litres in her car, to celebrate. And the Canadian company Carbon Engineering has just built a pilot plant to suck one to two tonnes of carbon dioxide from the air daily, turning it into 500 litres of diesel. The process requires electricity, but if the start-ups use renewable electricity they can produce diesel that is carbon neutral. In other words, burning it in your car only returns to the atmosphere the CO2 removed in the first place.

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Mark wrote:In other words, burning it in your car only returns to the atmosphere the CO2 removed in the first place.

Shame they won't just bury it.

It is definitely one way of storing the sun's energy to use at night but is it the most efficient?

It can't replace the massive amounts of oil that we get from fossil sources though because the Energy Returned On Energy Invested is far too low. It wouldn't give enough net energy to repay the energy expended on its production. Charles Hall et al (Energy and the Wealth of Nations) have estimated that an EROEI of at least 5 is required from any energy source to be sustainable.

BAU just isn't possible without the massive input of energy we are getting from fossil fuels and the input is so massive that it is virtually impossible to replicate from renewables unless we can find a natural, low energy, low temperature way of manufacturing ways of harnessing the sun's energy.

emordnilap wrote:

Mark wrote:In other words, burning it in your car only returns to the atmosphere the CO2 removed in the first place.

Shame they won't just bury it.

A friend of mine discovered this story a while back. Apparently Audi are putting a lot of money into it. His view was that, for every two litres produced, one should be used and the other buried.

This has been discussed before, and I am no more hopefull this time than last time.
There is nothing actually impossible in the proposal, it breaks no laws of physics.
To refer to diesel fuel from thin air is rather misleading, it might be more accurate to refer to diesel fuel from electricity, and a great deal of electricity at that.

A litre of diesel fuel contains about 13*KWH, so to make it from electricity would need at least 13* KWH per litre.
In fact the processes involved are so complex, with so many sources of loss, that an input of at least 50KWH per litre seems likely.
At current prices that would be about £7.50 a litre just for the electricity input.
Now consider the costs of plant and machinery, the cost of the land on which the facility is built, wages, employee benefits, property and revenue taxes, insurance, and perhaps even a profit for those risking all that capital.

Battery road vehicles, electric railways, and sailing ships start to look more sensible. Or for local journeys, walking, cycling, or riding a horse.

*EDIT, in fact as has been pointed out, diesel fuel contains about 11KWH per litre, 13 KWH per kilo, see the following post.

Diesel has 11KWh/l, not 13. It has 13KWh/Kg, but its density is about 0.85 Kg/l

Otherwise, yes.

PS_RalphW wrote:Diesel has 11KWh/l, not 13. It has 13KWh/Kg, but its density is about 0.85 Kg/l

Otherwise, yes.

Yes you are correct, I have edited to reflect this.

Mark wrote:The process requires electricity.....

The process requires considerably more energy than the final diesel product contains, clue's in the price 2-3x higher. This shouldn't be considered a source of energy, it's energy consumption.

Using a machine to suck CO2 out of the atmosphere (0.04%!) is also daft while there are still plenty of chimneys pumping out high concentration CO2. Anyone trying to sell such a machine might as well be selling snake oil.

Agree, and indeed IIRC, in a previous thread on this subject I suggested that the carbon dioxide be obtained from an industrial brewery, as the fermentation gasses are almost pure carbon dioxide.
The water might be better obtained from a well, or from rainwater capture, or from a water company, rather than being extracted from the air.

adam2 wrote:Agree, and indeed IIRC, in a previous thread on this subject I suggested that the carbon dioxide be obtained from an industrial brewery, as the fermentation gasses are almost pure carbon dioxide.
The water might be better obtained from a well, or from rainwater capture, or from a water company, rather than being extracted from the air.

In that case then, wouldn't you be better off, in economic terms at least, using industrial strength alcohol as a bio-diesel?

Some of the distilleries make for gin make liquor that is 86% alcohol - which is then obviously watered down.

BTW in beer making in the UK, the water undergoes a process known as "Burton-isation " - it is made to the composition of water in the Burton area. This frequently involves adding sulphuric acid to the water to get the chemistry right.

The use of alcohol as a road fuel is frequently proposed, and it is already used to a limited extent.
The properties of alcohol make it more suitable as a petrol substitute or a petrol blending ingredient, than as a substitute for diesel fuel.

The main drawbacks are the amount of land needed to grow the fermentable crops, and the amount of diesel or other oil derived inputs to sow, fertilise, kill pests, harvest, transport, and process the crop. The actual distillation requires heat, usually from natural gas, though renewables could be used.

The diesel from electricity proposal does at least have the merit of not diverting food crops or potential food growing land, into the production of road fuel.
SOME land would be needed for the factories and for the nuclear power plants to supply the electricity, but not that much compared to biofuels.

raspberry-blower wrote:
BTW in beer making in the UK, the water undergoes a process known as "Burton-isation " - it is made to the composition of water in the Burton area. This frequently involves adding sulphuric acid to the water to get the chemistry right.

A bit O/T but I think that you are mistaken regarding this.
Some styles of beer from Burton on Trent were famous and sought after due to the flavour imparted by the local water which contained significant amounts of SULPHATES.
Brewers in other areas emulated this by adding SULPHATES, usually gypsum, to the local water in order to simulate the gypsum rich water of Burton on Trent.
I do not believe that sulphuric acid was used, or not least not added to the brewing water. Sulphuric acid might have been used to produce SULPHATES, but even that seems unlikely as natural sources exist at low cost.

adam2 wrote:

raspberry-blower wrote:
BTW in beer making in the UK, the water undergoes a process known as "Burton-isation " - it is made to the composition of water in the Burton area. This frequently involves adding sulphuric acid to the water to get the chemistry right.

A bit O/T but I think that you are mistaken regarding this.
Some styles of beer from Burton on Trent were famous and sought after due to the flavour imparted by the local water which contained significant amounts of SULPHATES.
Brewers in other areas emulated this by adding SULPHATES, usually gypsum, to the local water in order to simulate the gypsum rich water of Burton on Trent.
I do not believe that sulphuric acid was used, or not least not added to the brewing water. Sulphuric acid might have been used to produce SULPHATES, but even that seems unlikely as natural sources exist at low cost.

Actually I have been on several brewery trips in the South East and, due to the high chalk content of the well water, this is the preferred method employed by many of the breweries to obtain the sulphate level.
All of the breweries I have visited said they "Burtonise" the water and that this was industry standard practice. This doesn't mean that brewers can't brew from a different standard of water, mind.

Sulphuric acid added to calcium carbonate rich water would produce calcium sulphate (gypsum), carbon dioxide and water

H2SO4 + CaCO3 = CaSO4 + CO2 + H2O approximately.

The calcium carbonate rich water is alkaline while the gypsum rich water is acidic.

There would be no sulphuric acid left in the beer at the end of the process.

The other disadvantage with putting alcohol into petrol is that the alcohol absorbs water from the air and causes problems in the carburettor and with the seals which can be susceptible to water damage. Lawn mower, chainsaw and the like, engines which are left for long periods unused should be drained of fuel and new petrol used when they are refilled because of the significant amount of water which can be absorbed. Cans of petrol with alcohol in it stored for long periods are very susceptible to this problem.

I've read something similar on instructions for petrol-driven items. The basic advice seems to be to fill the tank to the top, leaving no or minimal air from which to draw moisture. Draining it completely before storage makes more sense but it's one reason why I always refill tanks fully after use.