Hey guys. I have a question.
What are the processes that can create some type of fossil fuels from electricity?
Basically, is it possible and how, to make either gas or coal or diesel or something like that from nothing but air, electricity and maybe water or something else every cheap?
Why doesn't anyone make it?
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Cause if we had chemistry that advanced we could do a lot more than just make synthetic fossil fuels
So we can't?
I mean we can make hydrogen pretty easily by electrolysis, but hydrogen is not easily stored...
They do, just not in the way you think they do.
I forget what the process is called, butt for a hundred years we've made ling chain linear hydrocarbons by heating up inorganic CO and H2. The thing is we get these from burning fossil fuels.
So really the reason why it's not done is that we would produce less energy than it would take to maje the fuel, such as using that electricity to provide power to the user. The only reason would be to make fuels that have niche requirements and are of limited supply.
If you're interested, there's lots of research on how to take the CO2 effluent captured by power plants and turn it into products, I believe they recently made it economical for ethanol as the end product.
google Power To Gas.
the US Navy experimented with the idea. I don't have their feasibility study on hand, but basically they wanted to use excess power from the nuclear reactor on board a carrier to split hydrogen and dissolved CO2 from seawater and process it into jet fuel.
the process is energy intensive, but the machinery is quite simple with very few moving parts (its almost all electrical and static filters). getting from seawater to methane was easy, but going from methane to more complex hydrocarbons was the real pain in the ass.
>nrl.navy.mil
?
couldn't you google this?
obviously you can... especially natural gas CH4
theres just no economic purpose to do so
>couldn't you google this?
Sorry to interrupt the flow of '1=/=0.999...' discussions here on Veeky Forums, but I tried googling and it failed me.
thx
>What are the processes that can create some type of fossil fuels from electricity?
They generally start with making hydrogen from water:
en.wikipedia.org
There are elaborations on the process, so you can also do things like use an ammonium bisulfate solution to make hydrogen and hydrogen peroxide, or a hot salt solution to make hydrogen and sodium chlorate, so you have two potentially valuable products rather than just hydrogen and the waste gas oxygen.
Once you have hydrogen, you can upgrade it to more storable fuels by reacting it with carbon dioxide in a number of reactions:
The reverse water-gas shift reaction exchanges hydrogen and CO2 for water and carbon monoxide.
en.wikipedia.org
A mixture of hydrogen and carbon monoxide is known as "synthesis gas":
en.wikipedia.org
...and it's useful for making all kinds of organic chemicals.
Various sorts of hydrocarbons can be made with the Fischer-Tropsch process:
en.wikipedia.org
One simple, efficient reaction for making methane is particularly of interest for production of rocket propellant on Mars:
en.wikipedia.org
You can pyrolyse the methane (heat it until it decomposes, typically depositing pyrolytic carbon on the walls of a pipe) to make carbon and hydrogen, and recycle the hydrogen so your product is a coal-like solid carbon.
Other simple, efficient reactions produce methanol or ammonia. Methanol is a good gasoline substitute that can be further converted to dimethyl ether, a propane-like substance good in diesel engines.
Another option for production of solid carbon or carbon monoxide is electrolysis of molten carbonates, but this is more of an area of development than a mature industrial process. An advantage here is that the depleted source material can absorb more CO2 from the atmosphere and refresh itself.
As for the reason we don't do it, Earth has subsurface lakes of hydrocarbons, mountains of coal, and vast reservoirs of natural gas. It's easier to just collect and refine that than make new stuff, especially considering the low concentration of CO2 in the atmosphere, which makes that difficult and costly to gather as material for synthetic fuel.
Solar power is now joule-for-joule cheaper than coal-fired electric, but it needs to get much cheaper than that to be competitive for fuel synthesis.
this is why every synthetic fuel effort uses water. water holds concentrations of CO2 hundreds of times higher than air.
Synthetic fuel will be pointless because in 10 years or less batteries will be cost competitive with fuel
...but they don't. Most "synthetic fuel efforts" start from other fossil fuels, while CO2 capture efforts often aim to capture atmospheric rather than aquatic CO2.
>synthetic fuel efforts
yes you're right. i should have said power to gas efforts.
>while CO2 capture efforts often aim to capture atmospheric rather than aquatic CO2
the ocean is a giant carbon sink for our atmosphere. drawing CO2 out of the ocean draws it out of the atmosphere. concentration gradients my man.
Trying to make energy (some type of energy storage device such as carbohydrates, ethane, methane) from energy?
Do you not see how illogical this is?
Batteries will never be cost-competitive with fuel for long-term storage, nor will they ever reach equivalent energy density.
Electric cars might catch on, but not electric intercontinental airliners or battery storage of power generated in summer for use in winter.
>>while CO2 capture efforts often aim to capture atmospheric rather than aquatic CO2
>the ocean is a giant carbon sink for our atmosphere. drawing CO2 out of the ocean draws it out of the atmosphere.
Of course, but this is irrelevant to the point I was making: people working on ways to get CO2 from the environment often choose to collect it from the air, rather than the water.
If you collect it from water, you have to worry about the chemicals you use to bind the CO2 washing away in the water, or getting contaminated with other things in the water.
>you have to worry about the chemicals you use to bind the CO2 washing away in the water
no. the newer technology is almost entirely electrical with the only by products being seawater with slightly higher salinity. there are no chemical inputs.
The term is, "biodiesel". It isn't electric-based from the start, but the chemicals and biomass used requires tons of energy to get to that point.
Biomethane is a bit better since the microbes' work tips the scales of energy use in our favor and make it so we get more energy out of the system than we put in. Basically, microbe slavery. Electricity isn't needed in this either, but it helps. Like biodiesel the chemicals and biomass used requires tons of energy to get to that point. However, it is far less than biodiesel systems.
The best thing to go straight from electric to something combustible is hydrolysis, as mentioned. However, it is far more efficient to simply use the electric straight off.
Algae/biodiesel. This has already been done but it's more expensive since it's new technology. Biobutanol or something?
>is it possible and how, to make either gas or coal or diesel or something like that from nothing but air, electricity and maybe water or something else
Yes.
>very cheap?
No. At least not in the short or medium term.
One could get hydrogen from electrolysis and combine it with CO2 captured from air in a Sabatier reaction to synthesize Methane or similar reactions for higher hydrocarbons. But the most expensive with that is the energy demand for capturing CO2 from air. Even using only CO2 sources with high concentration like waste from steel making etc would not be able to compete economically with current energy sources.
What does long term storage mean? Why would anyone be doing that?
Once batteries reach a point, you will see private personal electric planes
Fuel is not free, eventually there's a point that rechargable batteries is cost effective to burning fuel
Nothing illogical about it once you know terms like "energy density" or "storage losses".
We really only need working graphene super-conductors that can be produced cheaply, then the stage will be set for electric vehicles to overtake fossil fuel ones.
You can make methane by fart
>What does long term storage mean? Why would anyone be doing that?
Seriously? You're asking why anyone would want to store large amounts of energy in the long term when they depend on an intermittent source of energy that's affected by the weather?
>Once batteries reach a point, you will see private personal electric planes
Rechargeable batteries will always have considerably lower specific energy than fuel, so electric planes will be short-range. As for private personal planes, there's not going to be any more reason for that in the future than there is now. Aviation is limited because no one wants random yahoos constantly flying overhead.
>Fuel is not free
It's as free as electricity is. How many times do I have to point out that you can synthesize fuel from air, water, and electricity?