39 replies to this topic

[davidlan]

In my never ending quest to find something of interest on the internet I stumbled upon this small story.

https://www.ornl.gov...irectly-ethanol

 

Jammed in below the latest salacious tales from Coronations street and which Kardashian is going to have

Wayne Rooney's love child I noticed this headline.

 

"Lab converts Carbon dioxide to ethanol"

 

I figured they were kidding but took a read anyway. Now forgive me if this has been done before, but should this not be an Euraka Moment or is this just a tempting 'it will never leave the Lab' Breakthrough?

 

Dav

[saudoso]

I guess it's about the energy balance, which was not mentioned in the article

[BRG]

It's a great idea.  By converting the CO² from your car's exhaust back into fuel,we will have an automotive perpetual motion machine!  Take that, Elon Musk!

 

Now back to Khloe Kardashian and Wayne Rooney - no wonder his playing is looking a bit rubbish this season.

[davidlan]

Now I have the image of a funky motorbike with a exhaust coming off the engine going to a  

converter and then back into the gas tank. 

 

Its Kim not Khloe and they say Rooney is just taking the rap.

 

Dav

[gruntguru]

 

I guess it's about the energy balance, which was not mentioned in the article

Exactly. If the conversion only requires heat energy and the efficiency is anything like 50%, this could be useful technology.

[bigleagueslider]

Converts CO2 and hydrogen (from some unnamed source) into ethanol using electrical power and a metal catalyst in a single step. Of course you can also produce hydrogen gas, which happens to be a very clean fuel, from H2O in a single step using electrolysis. And it just so happens that H2O vapor is also a significant greenhouse gas.

[imaginesix]

It's a great idea.  By converting the CO² from your car's exhaust back into fuel,we will have an automotive perpetual motion machine!  Take that, Elon Musk!
 
Now back to Khloe Kardashian and Wayne Rooney - no wonder his playing is looking a bit rubbish this season.

You know you can turn electricity into motion and back to electricity, and it's still not a perpetual motion machine?

Maybe you should just keep tuned into the Kardashian network.

[gruntguru]

 

Converts CO2 and hydrogen (from some unnamed source) into ethanol using electrical power and a metal catalyst in a single step. Of course you can also produce hydrogen gas, which happens to be a very clean fuel, from H2O in a single step using electrolysis.

In that case, I am suddenly much less excited.

 

 

And it just so happens that H2O vapor is also a significant greenhouse gas.

You don't seriously believe that man-made water vapor can be a significant contributor to the greenhouse effect?

[jcbc3]

You know you can turn electricity into motion and back to electricity, and it's still not a perpetual motion machine?

Maybe you should just keep tuned into the Kardashian network.

 

whooosh

[BRG]

You know you can turn electricity into motion and back to electricity, and it's still not a perpetual motion machine?

Maybe you should just keep tuned into the Kardashian network.

  As if I was being serious.....

[Afterburner]

In my never ending quest to find something of interest on the internet I stumbled upon this small story.
https://www.ornl.gov...irectly-ethanol

Jammed in below the latest salacious tales from Coronations street and which Kardashian is going to have
Wayne Rooney's love child I noticed this headline.

"Lab converts Carbon dioxide to ethanol"

I figured they were kidding but took a read anyway. Now forgive me if this has been done before, but should this not be an Euraka Moment or is this just a tempting 'it will never leave the Lab' Breakthrough?

Dav

This depends on how reliably they can synthesize the semiconductor they're using as a catalyst. Theoretically speaking there will be a nanospike arrangement that
produces a catalytic efficiency high enough to make this thing useful, but practically speaking reliably synthesizing such a catalyst is unrealistic (for now).

They talk about achieving an 83% selectivity for ethanol as a product with methane, hydrogen, and carbon monoxide as additional possible products. Production of ethanol and other hydrocarbons from reduction with copper catalysts isn't new, but reduction with selectivity this high is. Basically what's going on is the copper is still performing the reduction, but the carbon nanospikes are stabilizing the intermediates favorable to the pathway that results in ethanol as a product so that they're kinetically (not thermodynamically) preferred over other intermediates for the multitude of other possible reductions. They assume that the first intermediate in the ethanol pathway is the rate-limiter so overcoming that makes it easy for the rest of the as-yet-to-be-determined reduction mechanism to occur.

N-doped graphene is key because it modifies the electron distribution through the graphene due to electronegativity differences and impurities in the framework of the nanospikes, apparently creating an active site for the catalyst; since it's electron-poor I'm assuming one of the oxygens on CO₂ lands in it. Whatever intermediate comes next is made happy by this localized partial positive charge from the N-doped graphene.

The biggest hindrance in this whole thing, and the one thing that stuck out to me when reading the paper, is that the overpotential is ridiculous; not really an electrochemist, but to my understanding that means that on a scale necessary for a fuel cell this thing is going to put off a crap-ton of heat (bond formation is exothermic). What they've managed to do is produce something that's outrageously selective, which is great, but the thermodynamic efficiency of the catalyst itself still isn't high enough for it to be viable economically, which the authors note at the end of the paper. This can be rectified by production of a more efficient catalyst (no s#!t, I know), which might be possible if they can conclude the mechanism and then design the nanospikes to assume a favorable conformation for it to occur.

My take on it, anyway. Read the paper and found it thoroughly fascinating. Thanks for sharing.

[Kelpiecross]

There is a lot of work being done at present on converting CO2 into various liquid fuels and also CO - which is a useful fuel but very dangerous.
One of the main problems in the process is the lack of a feedstock - the CO2. Plenty in the atmosphere but at a very low concentration - you would have to process a lot of air to get a useful amount of CO2.
It has been suggested that the process would work best on the exhaust from a coal-fired power station. So essentially you would be burning fuel to make fuel - possibly the process could be regarded as a method of converting coal into a liquid fuel.

[imaginesix]

  As if I was being serious.....

Sorry, I didn't get the reference you made and I was used to reading ridiculous criticisms here of far-fetched ideas whose benefits weren't immediately obvious, so I incorrectly assumed that was your angle. My bad.

[bigleagueslider]

In that case, I am suddenly much less excited.

 

You don't seriously believe that man-made water vapor can be a significant contributor to the greenhouse effect?

Water vapor is considered a greenhouse gas. Why would it matter if the water vapor is man-made?

 

"The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone."

[saudoso]

Water vapor is considered a greenhouse gas. Why would it matter if the water vapor is man-made?

 

"The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone."

Now that's something I'd like to see the greenies tackling. 

 

Curb the emission of water vapor. 

 

Just face it people, it's your most important responsibility. Think of the children!

[saudoso]

Now seriously. You can't think like that. There's no point discussing anything you can't control or even noticeably influence like water vapor emissions.

[Charlieman]

There's no point discussing anything you can't control or even noticeably influence like water vapor emissions.

That's why climate scientists try to separate out anthropogenic environmental change --  effects resulting from human activity.

 

Scientists study and discuss natural effects in order to see how the world works. We can't know whether/how much human activity changes nature unless we measure it.

[carlt]

It has been suggested that the process would work best on the exhaust from a coal-fired power station. So essentially you would be burning fuel to make fuel - possibly the process could be regarded as a method of converting coal into a liquid fuel.

Have you got a link/source for this 

[saudoso]

That's why climate scientists try to separate out anthropogenic environmental change --  effects resulting from human activity.

 

Scientists study and discuss natural effects in order to see how the world works. We can't know whether/how much human activity changes nature unless we measure it.

I very much doubt we are able to make a dent on nature's water vapor emission. The amount of energy involved is staggering. 

 

Where's the research on that?

[imaginesix]

The thinking I've read on water vapour is that with increased temperatures the air can hold more moisture, so the increased water vapour is a consequence of warming, which then contributes to it by having the property of being a GHG.

It's a positive feedback loop in the climate cycle, not necessarily a target for direct action to affect control over the cycle.

Edited by imaginesix, 22 October 2016 - 20:32.

[saudoso]

The thinking I've read on water vapour is that with increased temperatures the air can hold more moisture, so the increased water vapour is a consequence of warming, which then contributes to it by having the property of being a GHG.

It's a positive feedback loop in the climate cycle, not necessarily a target for direct action to affect control over the cycle.

I can see that, but it's not what was being suggested above.

[Charlieman]

I very much doubt we are able to make a dent on nature's water vapor emission. The amount of energy involved is staggering. 

 

Where's the research on that?

saudoso is a fake, a wind up merchant. Saudoso is 47 years old and lives in Sao Paulo, probably a con artist.

[saudoso]

I wish.

[gruntguru]

You don't seriously believe that man-made water vapor can be a significant contributor to the greenhouse effect?

 

 

Water vapor is considered a greenhouse gas. Why would it matter if the water vapor is man-made?

Because the rate of generation of water vapour by nature is a colossal number compared to man-made and is one side of an equilibrium condition. If evaporation rates increase, atmospheric moisture loading (humidity) increases and precipitation increases to restore the balance.

 

The equilibrium point shifts primarily as a result of temperature change. Man made water vapour is just another way of adding heat to the environment (It happens to be latent heat rather than sensible heat.) Either way, adding heat to the environment causes a temperature increase which shifts the equilibrium point towards higher humidity.

 

Of course the higher temperature results in increased IR emission into space so the added heat ends up dissipating anyway, so the natural water cycle with some extra evaporation thanks to mankind remains self-regulating. The difference now is with other more permanent GHG's in the atmosphere, there is an underlying reduction in IR emission to space, higher average temperatures and a more permanent shift in the equilibrium point - which clearly makes water vapour a significant warming factor - but not in its own right.

[imaginesix]

I can see that, but it's not what was being suggested above.

As far as I can tell you were the first and so far only one to suggest it should be a target for climate action in post 15 "I'd like to see the greenies tackle that".

[Canuck]

I heard the sarcasm clearly. His intent,to mock the notion that water vapour would be the next impossible and ridiculous problem.put forth by certain groups was, I thought,pretty clear.

[saudoso]

As far as I can tell you were the first and so far only one to suggest it should be a target for climate action in post 15 "I'd like to see the greenies tackle that".

What our friend from the north said. And no, I wasn't the first to read it like this in this thread.

[Kelpiecross]

Have you got a link/source for this

http://rsta.royalsoc...t/368/1923/3343

[gruntguru]

Good link KC. There are some great charts and diagrams in that paper. eg

 

Edited by gruntguru, 25 October 2016 - 00:03.

[Canuck]

I would not have guessed that Iceland used more energy than everyone else (per capita). Surprising.

[gruntguru]

Makes sense that cold climates correlate to higher energy consumption. Saudi Arabia (yet again) proves to be a strong outlier - on two counts - high energy consumption for such a warm climate and low "human development" for such a high consumer of energy.

[Charlieman]

Makes sense that cold climates correlate to higher energy consumption. Saudi Arabia (yet again) proves to be a strong outlier - on two counts - high energy consumption for such a warm climate and low "human development" for such a high consumer of energy.

But lots of air conditioning for the rich...

 

The chart shows kg oil equivalent consumption per capita which is "unfair" to Iceland which uses geothermal and hydro for a lot of energy requirements -- almost 100% for electricity generation and domestic heating. We can use that chart to see how much energy is required to maintain lifestyles and industries in particular countries, but it tells us little about types of energy.

 

New car sales in Iceland are about 1,000 per month (200,000 cars in total), mostly small/medium SUVs and town cars so not much gas guzzling. Alternative fuels for cars and boats (or even planes) aren't going to make much of an impact. Icelanders seem to be inventive about how they use their energy resources for mineral extraction, providing good lessons for everyone.

[thegforcemaybewithyou]

This might explain why the per capita rating is that high for Iceland. Cheap electricity attracts energy intensive companies.

 

https://askjaenergy....ity-in-iceland/

 

Edited by thegforcemaybewithyou, 25 October 2016 - 16:40.

[Charlieman]

This might explain why the per capita rating is that high for Iceland.

It explains why kg oil equivalent consumption per capita looks bad for Iceland.

 

It doesn't explain why we use the measure when trying to understand types of energy usage.

[Fat Boy]

But lots of air conditioning for the rich...

 

 

...and a whole lot of F-You for the underlings.

[bigleagueslider]

The UN researchers seem to have conveniently missed this little factor when calculating their "Human Development Index" statistic.

 

http://www.cnsnews.c...ntries-combined

 

[BRG]

When I used to deal with UNDP matters for the UK government, the Human Development Index was always a controversial instrument.  Everyone had a beef with it over something that didn't reflect well on their particular country.  It is all about statistics and you can prove anything with them.

 

I was amused about the article in CNS News.  The USA always used to be in arrears of its assessed contributions.  There were sometimes motions to debar any state in arrears from voting in the UN.  I bet that wouldn't go down well with CNS News!

[davidlan]

I do have to admire you guys.

 

I originally open this thread to highlight what I thought was an interesting 

development in chemistry, We have now evolved to the use of AC's in Iceland

and how Water vapor will bring on the next ice age.

 

So what's next?

 

Dav

[Canuck]

I'm staying on the AC tangent with a personal anecdote.

 

Makes sense that cold climates correlate to higher energy consumption. Saudi Arabia (yet again) proves to be a strong outlier - on two counts - high energy consumption for such a warm climate and low "human development" for such a high consumer of energy.

Having lived in the Middle East for a brief period, I can attest the staggeringly cold AC that blasts from everywhere, all the time. It's the only place I've ever been where I carried a layer for going inside.

[Kelpiecross]

I would like to point out that electricity can hardly be thought of as being wasted in Iceland - much of it is converted into a permanent form as aluminium - unlike some other countries where it just disappears after being used for heating and cooling etc.