Audi creates "synthetic diesel" from air, water, and electricity...?

K

Kittamaru

Ashes to ashes, dust to dust. Adieu, Sciforums.
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https://www.audi-mediaservices.com/...tteilungen/2015/04/21/fuel_of_the_future.html

Fuel of the future: Research facility in Dresden produces first batch of Audi e-diesel
  • The verdict: Pilot plant produces high-quality diesel fuel
  • No need for mineral oil: e-diesel made from water, CO2 and green power
  • Minister Wanka: “Synthetic diesel using CO2 is a huge success”
Audi has taken another big step in the development of new, CO2 neutral fuels: A pilot plant in Dresden has started production of the synthetic fuel Audi e diesel.

After a commissioning phase of just four months, the research facility in Dresden started producing its first batches of high‑quality diesel fuel a few days ago. To demonstrate its suitability for everyday use, Federal Minister of Education and Research Prof. Dr. Johanna Wanka put the first five liters into her official car, an Audi A8 3.0 TDI clean diesel quattro*, this Tuesday. “This synthetic diesel, made using CO2, is a huge success for our sustainability research. If we can make widespread use of CO2 as a raw material, we will make a crucial contribution to climate protection and the efficient use of resources, and put the fundamentals of the “green economy” in place,” declared Wanka.

The Dresden energy technology corporation sunfire is Audi’s project partner and the plant operator. It operates according to the power‑to‑liquid (PtL) principle and uses green power to produce a liquid fuel. The only raw materials needed are water and carbon dioxide. The CO2 used is currently supplied by a biogas facility. In addition, initially a portion of the CO2 needed is extracted from the ambient air by means of direct air capturing, a technology of Audi’s Zurich‑based partner Climeworks.

Reiner Mangold, Head of Sustainable Product Development at Audi, sees Audi e‑diesel and Audi e‑fuels in general as an important component that complements electric mobility: “In developing Audi e-diesel we are promoting another fuel based on CO2 that will allow long‑distance mobility with virtually no impact on the climate. Using CO2 as a raw material represents an opportunity not just for the automotive industry in Germany, but also to transfer the principle to other sectors and countries.”

Production of Audi e‑diesel involves various steps: First, water heated up to form steam is broken down into hydrogen and oxygen by means of high-temperature electrolysis. This process, involving a temperature in excess of 800 degrees Celsius, is more efficient than conventional techniques because of heat recovery, for example. Another special feature of high-temperature electrolysis is that it can be used dynamically, to stabilize the grid when production of green power peaks.

In two further steps, the hydrogen reacts with the CO2 in synthesis reactors, again under pressure and at high temperature. The reaction product is a liquid made from long‑chain hydrocarbon compounds, known as blue crude. The efficiency of the overall process – from renewable power to liquid hydrocarbon – is very high at around 70 percent. Similarly to a fossil crude oil, blue crude can be refined to yield the end product Audi e‑diesel. This synthetic fuel is free from sulfur and aromatic hydrocarbons, and its high cetane number means it is readily ignitable. As lab tests conducted at Audi have shown, it is suitable for admixing with fossil diesel or, prospectively, for use as a fuel in its own right.

The Federal Ministry of Education and Research is supporting the sunfire project, which started in May 2012. Construction work on the facility in Dresden‑Reick kicked off in July 2013 and the plant was commissioned on November 14, 2014. The plant is set to produce over 3,000 liters (792.5 US gal) of Audi e‑diesel over the coming months. Audi is sunfire’s exclusive partner in the automotive sector.

Over and above the partnership with sunfire, Audi has been active in the development of CO2‑neutral fuels – Audi e‑fuels – since 2009. The Audi e‑gas plant in Werlte, Lower Saxony, already produces Audi e‑gas (synthetic methane) in a comparable manner; drivers of the Audi A3 Sportback g‑tron* can fill up on it using a special fuel card. Audi is also conducting joint research into the synthetic manufacture of Audi e‑gasoline with Global Bioenergies, of France. In a further project, Audi has joined forces with the U.S. company Joule, which uses microorganisms to produce the synthetic fuels Audi e‑diesel and Audi e‑ethanol.

Fuel consumption of the models named above:

Audi A8:
Combined fuel consumption in l/100 km: 5.9 (39.9 US mpg)**;
Combined CO2 emissions in g/km: 155 (249.4 g/mi)**

Audi A3 Sportback g-tron:
CNG consumption in kg/100 kilometers: 3.3 – 3.2 (71.3 – 73.5 US mpg)**;
Combined fuel consumption in l/100 km: 5.2 – 5.0 (45.2 – 47.0 US mpg)**;
Combined CO2 emissions in g/km (CNG): 92 – 88 (148.1 – 141.6 g/mi)**;
Combined CO2 emissions in g/km (gasoline): 120 – 115 (193.1 – 185.1 g/mi)**

**The fuel consumption and the CO2 emissions of a vehicle vary due to the choice of wheels and tires. They not only depend on the efficient utilization of the fuel by the vehicle, but are also influenced by driving behavior and other non-technical factors.
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Well... that is interesting!
 
It's encouraging if it's true.

The cynic in me is whispering in the ear of my inner conspiracy theorist that "Big Oil (tm)" isn't going to like it...
 
Daecon said:
It's encouraging if it's true.

The cynic in me is whispering in the ear of my inner conspiracy theorist that "Big Oil (tm)" isn't going to like it...
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Why would "Big Oil" take a view on this that is any different from the view it takes on nuclear power or renewables?

Must admit though that I had to check it was not an AprilFool joke, when I saw the name of the minister quoted :biggrin:.
 
Kittamaru said:
Well... that is interesting!
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We've known about this for almost a century. All the processes are well known - electrolysis, Sabatier, Fischer-Tropsch, RWGS. The process has a negative EROEI so it's not useful as a source of energy.
 
billvon said:
We've known about this for almost a century. All the processes are well known - electrolysis, Sabatier, Fischer-Tropsch, RWGS. The process has a negative EROEI so it's not useful as a source of energy.
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billvon - if it were made using, say, solar power as the primary method of creating the fuel, shouldn't it still result in a net gain (if only because of the reduction in fossil fuel consumption, if nothing else?)
 
Kittamaru said:
billvon - if it were made using, say, solar power as the primary method of creating the fuel, shouldn't it still result in a net gain (if only because of the reduction in fossil fuel consumption, if nothing else?)
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Well, no - solar is only about 15% efficient best case. Then you add a hideously inefficient chemical process and you're down in the weeds.
You can ignore the solar conversion efficiency, of course, and say that the Sun is free so you can ignore its energy. However, in that case, you are still far better off using the electricity to drive cars, trucks and trains than trying to convert that electricity to fuel, to thermal energy and back to mechanical energy. It may find some limited application in critical missions (military aviation, spacecraft etc) but overall there are far better uses for solar electricity, and far better sources for liquid fuels.
 
Hm... fair enough I guess - I wonder what the byproducts of this synthetic fuel are (and what the emissions standards are for it)
 
As long as I don't have to stop driving my car for any reason.

Would like to see some numbers on energy return over investment on this fuel.
 
Hi billvon.

Good posts.

billvon said:
We've known about this for almost a century. All the processes are well known - electrolysis, Sabatier, Fischer-Tropsch, RWGS. The process has a negative EROEI so it's not useful as a source of energy.
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billvon said:
Well, no - solar is only about 15% efficient best case. Then you add a hideously inefficient chemical process and you're down in the weeds.
You can ignore the solar conversion efficiency, of course, and say that the Sun is free so you can ignore its energy. However, in that case, you are still far better off using the electricity to drive cars, trucks and trains than trying to convert that electricity to fuel, to thermal energy and back to mechanical energy. It may find some limited application in critical missions (military aviation, spacecraft etc) but overall there are far better uses for solar electricity, and far better sources for liquid fuels.
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I never thought I would say this, but billvon is 100% correct in this case.

Although it sounds super techie cool, Audi e-diesel cannot save the world.

This thread has run it's course.



---Futilitist:cool:
 
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billvon said:
We've known about this for almost a century. All the processes are well known - electrolysis, Sabatier, Fischer-Tropsch, RWGS. The process has a negative EROEI so it's not useful as a source of energy.
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Agreed. This is just an inefficient, expensive, convoluted storage method. The only scenario where it could possibly make sense is if you had to use diesel, but it was ridiculously expensive. That is highly unlikely for anything other than airplanes, for which no reasonable alternatives exist. And the Peak Oil scenario that would drive it is decades away.
 
Kittamaru said:
Hm... fair enough I guess - I wonder what the byproducts of this synthetic fuel are (and what the emissions standards are for it)
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It's a circular process: it is made from CO2 and H2O so the products of burning it are CO2 and H2O. For the car and the emissions standards governing it, nothing changes (though it is likely freer of other pollutants).
 
Russ_Watters said:
Agreed. This is just an inefficient, expensive, convoluted storage method. The only scenario where it could possibly make sense is if you had to use diesel, but it was ridiculously expensive. That is highly unlikely for anything other than airplanes, for which no reasonable alternatives exist. And the Peak Oil scenario that would drive it is decades away.
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Actually... a thought.

What if, and I know it's a bit "out there"... but what if we could put a refinery in high-orbit... unfettered access to the sun for solar power generation. Draw CO2 from the space station (which, I believe, is currently just vented into space). As for the water - well, they don't actually need water, just the Hydrogen and Oxygen - could this be gathered from an ice-based comet?

Again, way, way out there in terms of feasibility... and probably not worth the cost of deployment and distribution.

Russ_Watters said:
It's a circular process: it is made from CO2 and H2O so the products of burning it are CO2 and H2O. For the car and the emissions standards governing it, nothing changes (though it is likely freer of other pollutants).
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That's what I was thinking... very cool, if impractical.
 
Kittamaru said:
What if, and I know it's a bit "out there"... but what if we could put a refinery in high-orbit... unfettered access to the sun for solar power generation. Draw CO2 from the space station (which, I believe, is currently just vented into space). As for the water - well, they don't actually need water, just the Hydrogen and Oxygen - could this be gathered from an ice-based comet?
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They are already doing something very similar. Water (transported from Earth) is split to create oxygen and hydrogen. The hydrogen is stored and the oxygen is breathed. The CO2 from the astronauts is then run through the Sabatier reaction to yield methane and water. The water is reused for oxygen; the methane is dumped.

Future versions may either save the methane for propellant (a small methane/oxygen engine for periodic orbital boosting) or break down the methane via pyrolysis to hydrogen and carbon. The carbon would be ejected and the hydrogen would be reused. This would allow a system where nothing needs to be imported from Earth other than food (and enough water to make up for the inevitable leaks.)
 
billvon said:
They are already doing something very similar. Water (transported from Earth) is split to create oxygen and hydrogen. The hydrogen is stored and the oxygen is breathed. The CO2 from the astronauts is then run through the Sabatier reaction to yield methane and water. The water is reused for oxygen; the methane is dumped.

Future versions may either save the methane for propellant (a small methane/oxygen engine for periodic orbital boosting) or break down the methane via pyrolysis to hydrogen and carbon. The carbon would be ejected and the hydrogen would be reused. This would allow a system where nothing needs to be imported from Earth other than food (and enough water to make up for the inevitable leaks.)
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Huh... very cool! I didn't realize the system they had was that efficient!

Do they store excess/extra oxygen as well? I would presume they must in the event of a failure of the atmospheric system?
 
Kittamaru said:
Do they store excess/extra oxygen as well? I would presume they must in the event of a failure of the atmospheric system?
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Yes, they have both bottled oxygen and perchlorate "candles" they can burn to release oxygen if they have problems.
 
I don't know what the news is.
I am old enough to ride on Sao Paulo's buses for free, so often jump on one of the many* going my way if only riding for 2 or 3 blocks to their next stop. At least half have "ecodiesel" written on their side, and under it in finer print "15% diesel made from sugar cane." At current exceptionally low oil prices, there probably is no, or very little money saved, but until recently ecodiesel was cheaper than diesel only. I think only the newer buses can use it. (Older ones may not be "flex fuel".)

Perhaps the new ones have some sort of "glow plugs" as adding alcohol, if that is all that is done, reduces compression ignition ("knocking" in car, its called) - why Flex fuel" cars that use pure alcohol give a little more HP than when they use gasoline. Not sure, but think they have higher compression ratio and delay the spark or something when using only gasoline, which few do as that is more expensive and lower power, but you could make a trip of more than 300 miles without stopping for fuel. (Alcohol's one disadvantage is a tank full range is only 70% of that of gasoline's) The fuel mix is continuously sensed and the computer controls spark timing or fuel air ratio or something so a "flex fuel" car can use any mix from pure gasoline to pure alcohol.

Another thing more than half the buses have printed on their sides (when translated from the Portuguese) which pleases me, goes like:
"Transport - The citizen's right / the government's duty."

Buses have there own lanes** which taxis with a passenger may use too. - They are often faster than driving your own car as Sao Paulo traffic can be terrible - I walk a lot and note which car I started with; it is not rare that I get well ahead of it, but am not sure when it does not catch up to me, if that is because it turned off to a side street or that for many blocks I was going faster.

* I once counted 17 busses, one just after the other, in their bus lane. They are color coded telling the district they will go to, from a central one where many pass thru, as often they are so close to one another that you can only read their small description of their route printed on the side, near the door. Also, most will not stop where a few others will - you need to walk a couple of blocks to where one you want to use for a long trip will stop, but for my typical "short assist trip," I can take anyone at any bus stop if it stops there. One or two are usually stopped to take on & discharge passenger, so I never need to wait.

** Most roads in Sao Paulo are asphalt but in the last few years the bus lanes have become mainly concrete. Almost no one not entitled to use them does so. I got into one for less than a block to make a turn from it more easily and got a ticket! - about $70 as I recall. Sao Paulo may not be able to catch many crooks, especially the elected ones, but they have many traffic cops, at least one at major intersections, constantly writing up tickets - their only job with unique brown clothing to distinguish them from real cops. Their salaries are low, so I bet the $Ro$I is greater than 1000!
 
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Folks, the only thing that controls whether this process will ever be of benefit is the cost of the electricity. If someone ever throws of the yoke of fear and begins building LFTRs (Liquid Fluoride Thorium Reactors) in quantity, they could power this process and have it be comparable to petro-fuels.
 
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