Carbon Dioxide From the Air Converted Into Methanol (gizmag.com)

Zothecula writes: The danger posed by rising levels of atmospheric carbon dioxide has seen many schemes proposed to remove a proportion it from the air. Rather than simply capture this greenhouse gas and bury it in the ground, though, many experiments have managed to transform CO2 into useful things like carbon nanofibers or even fuels, such as diesel. Unfortunately, the over-arching problem with many of these conversions is the particularly high operating temperatures that require counterproductive amounts of energy to produce relatively low yields of fuel. Now researchers at the University of Southern California (USC) claim to have devised a way to take CO2 directly from the air and convert it into methanol using much lower temperatures and in a correspondingly simpler way.

Comments

Energy in?

[Mr D from 63]

I see no mention of the energy put into the process vs the methanol output. Unless they are close, this would make no sense.

Re:Energy in?

[blue9steel]

Even if it wasn't net positive a low enough ratio might make it worth it to just pull the carbon out of the air and store the methanol in tanks. This might be a good use for surplus power at renewable generating sites, they could actually be carbon negative.

Re:Energy in?

[Hussman32]

From the article:

"To produce methanol from CO2 in the air, the researchers at USC's Dornsife College of Letters, Arts and Sciences first bubbled captured air through an aqueous solution of pentaethylenehexamine (PEHA), an ammonia-derived organic compound with multiple amino groups that – at raised temperatures – helps form chemical derivatives from alcohols. They then added a catalyst made from ruthenium (a member of the platinum group) to promote hydrogen attachment to the CO2 when the mixture was subject to high pressure.

The solution was then heated to around 125 to 165 C (257 to 359 F), and around 79 percent of the CO2 was converted into methanol. Though the resulting methanol was still mixed with water as it was produced, the researchers state that it can be easily separated using simple distillation processes. In addition, with the new method operating at such comparatively low temperatures, minimum decomposition of the catalyst meant that the researchers were able to repeat the process five times with minimal loss of the catalyst effectiveness. It also uses a homogeneous catalyst (that is, a soluble catalyst in solution with the chemicals it is reacting with) resulting in a simpler and faster "one-pot" process."

So they have to procure an amine in the pure form, mix it with purified water, heat it to 125 to 165 oC (a lot of energy, also under pressure), bubble the air through it (requiring at least the same pressure as the solution so there wouldn't be backflow) then recover the product using distillation (energy intensive). It's good chemistry and interesting catalysis, but I don't see how it will be cost-effective.

My guess is it would be cheaper to let a tree reduce the CO2, chop it down, and make the wood alcohol from that.

Re:Energy in?

[Obfuscant]

Trust me, it makes no sense... I can guarantee you that it takes a lot more energy input than you can get out of the methanol.

Every energy storage process takes more energy to store it than you get back out. I don't think getting energy back out of the methanol is the goal. Using it for other industrial processes that require methanol would be more useful.

but if you wan to produce methanol, just produce it the normal ways.

This method can be used on the output of current industrial processes that produce carbon dioxide and prevent it from being released in the first place. It's less efficient to loose the dragon and then hope a tree eats him than to just keep the dragon in the dungeon to start with.

Re:Energy in?

[Anonymous Coward]

The first thing is that power plants like nuclear are extremely inflexible. Basically they have to keep producing energy no matter what. This means that sometimes energy costs become negative. The producers of electricity from nuclear will actually pay you to use their power.

The next thing you need to know is that renewable, whilst mostly very flexible, has a relatively high capital, but very low marginal cost. This means that if there is a time when energy prices are low (e.g. due to nuclear power plants having to run during a low usage period) the renewable sources will be willing to sell you energy for almost any positive price.

This means that there is quite a bit of time when energy loss really doesn't matter nearly as much as you think. If you can just store some of the energy and use it at a later peak usage time, when it's many times more valuable, then you can make a profit even with huge energy losses.

Methane would be better than methanol. If you can produce methane you can power highly flexible gas power plants. Stiill, methanol is definitely better than nothing.

Re:Energy in?

[sumdumass]

Actually, it sounds like a perfect process for clean coal or other already existing energy production. The cooling towers alread carry enough heat to raise the temperature. As for pumping, well the generating already runs a bit under capacity so turning it up a little more shouldn't be too costly.

With a little tweaking, it could relatively easily reduce the carbon footprint of existing power plants.

Re:Energy in?

[Hussman32]

Pure amines are expensive, and purifying water isn't cheap at the volumes this would need (see my other notes).

Note the process says it's aqueous, and therefore liquid. The temperature is 125-165 degrees, above the normal boiling point of water. Steam tables say 6 bars/atmospheres of pressure at 165 oC for pure water. 6 atmospheres isn't too bad for a pressure vessel, but you will need some engineering behind it.

Condensation requires energy, especially if you need a vacuum.

 

Taking CO2 from the atmosphere??

[NotInHere]

What about not putting it there in the first place? It takes far more energy to extract the CO2 from the atmosphere than to build an energy chain that doesn't burn fossil sources. And if you really are keen on removing CO2, then just stop deforestation in south america.

Pray for Timothy

[sexconker]

timothy are you okay? Post if you are okay.

Re:Let's see if I've got this right...

[bobbied]

1: Install intake funnels over party caucuses, presidential debates etc etc. 2: Intake hot air > lower temperature > less global warming 3: Intake CO2 > methanol > less fossil fuel burning 4: PROFIT!

Just take their campaign cash from them, it will be easier, more efficient and might actually help the political process....

The blurb is plagiarised - this has to stop!

[Dr. Spork]

Unless user Zothecula is actually Colin Jeffery, the author of the article, then it is disgracefully misleading to represent the content of the blurb as something that "Zothecula writes". Those words were instead lifted directly from the Jeffery's article, and no indication was made that this was done. Where I teach, anyone who shows this little regard for proper attribution gets a failing grade for plagiarism, and a second offense gets you expelled. It's depressing that a for-profit journalistic outlet could be so indifferent to plagiarism. If the article must be quoted in the blurb, then fucking quote it. You have a tag for that, and you also have the power to use quotation marks.