Engineers find neat way to turn waste carbon dioxide into useful material

https://newsroom.unsw.edu.au/news/science-tech/engineers-find-neat-way-turn-waste-carbon-dioxide-useful-material

by geeklord • 6 years ago

123 85 6 years ago

newsroom.unsw.edu.au

Doesn't the net CO2 in the air increase?

So you harvest CO2 to into fuel. That fuel is burned and the CO2 is released back into the air. So net difference is zero.

But to harvest the CO2 you needed to generate a high amount of heat. That's extra CO2. So net CO2 is more.

It depends on the cost of harvesting that CO2.

lykr0n2• 6 years ago

You can use Solar and other renewable energy to power the conversion process. Progress is still progress.

I would much rather to pay more for net zero carbon fuel, then not do anything.

travisporter2• 6 years ago

It’s actually strange that no gas company is advertising something like this. I’ve seen so many industries advertise even the tiniest carbon offsets but why can’t BP or Exxon sell a net zero or at least low emissions fuel

perl4ever2• 6 years ago

I do not understand the concept that a property of a sum of a bunch of numbers somehow applies to those components.

Whether something is net zero depends on what you are adding it to; it's not inherent in that thing.

It's like, if you have a pile of blue things, then the pile is also blue. But other characteristics do not work that way. If you have a pile of things that each weigh 1 lb, then the pile does not weigh 1 lb.

nordsieck• 6 years ago

But to harvest the CO2 you needed to generate a high amount of heat. That's extra CO2. So net CO2 is more.

That depends on where they get their energy from.

pronoiac2• 6 years ago

I couldn't fetch the article, so I'm looking at the ScienceDaily page.

It's a process to turn:

* otherwise-waste carbon dioxide into (taking electricity)

* syngas, which can be turned into

* synthetic diesel, methanol, alcohol or plastics

Plastics could be a carbon sink I guess.

WJW• 6 years ago

You can get the required high amount of heat either through concentrating solar collectors or through any renewable form of electricity that you run through electric heaters. If you want to be fancy, you can use microwaves to very selectively heat only the parts you want to heat.

pronoiac2• 6 years ago

This looks like the same story: https://www.sciencedaily.com/releases/2020/06/200610152016.h...

Animats• 6 years ago

“We used an open flame, which burns at 2000 degrees, to create nanoparticles of zinc oxide that can then be used to convert CO2, using electricity, into syngas.”

Is this a real catalyst? (That is, it doesn't get used up in the process.) Or do they have to keep making more zinc oxide clouds to keep the process going? The paper summary is unclear about the energy inputs to this process.

Costs $10 to read the paper.

philipkglass• 6 years ago

It's a real catalyst. Full paper here:

https://sci-hub.tw/10.1002/aenm.202001381

I don't think it will have industrial significance any time soon, though. Catalysts and processes for the reverse water-gas shift reaction are better developed. The hope is that electrochemical catalysts like this can combine the electrolysis process for making H2 and the syngas production step into one, with lower equipment costs. It's hard for me to believe that it will overtake better established industrial processes. It's very hard to take a maybe-better process from lab scale to industry when there's already an established pair of processes that get to the same outcome.

My prediction: electrolyzers and catalytic processes will continue to be optimized separately, and combining those modules will continue to be more predictable and affordable than all-in-one electrocatalytic approaches like this.

elcritch• 6 years ago

Do you have more resources regarding the current state of art for the separate processes?

bit_logic3• 6 years ago

Every time there’s a discussion about synthetic carbon fuels, there’s the same frustrating replies. I want to reply to those with one statement: the whole point is to use excess power from solar/wind. There’s always the same replies pointing out how it’s more efficient to use the power directly in EV batteries, laws of thermodynamics, and other similar things. Those completely miss the point. Solar/wind is going exponential and we have a big problem of storing excess power. Massive really massive amounts of batteries is one option. But converting that into carbon fuels that work directly in existing infrastructure and is effectively carbon neutral is a good option too. That’s where the discussion should be, not pointless arguments about efficiency of EVs.

regularfry• 6 years ago

I was going to ask if anyone knew what the efficiency of this process was. Obviously we can't get a perpetual motion machine out of it, so it must be taking more energy to form the syngas than gets released from the fuel in the first place, right?

lstodd• 6 years ago

Right.

ZeroGravitas• 6 years ago

You don't need carbon to store energy, you can just stop at hydrogen (or use nitrogen to make ammonia).

Processes can be refitted to use pure hydrogen or it can just be added in small increments to existing gas burning plants.

Replacing anything that burns fuel with carbon in it with alternatives that dont is a better solution.

p1mrx• 6 years ago

Lots of homes and buildings use natural gas for heat. It would be nice to replace that with something carbon neutral, but the infrastructure can't handle hydrogen levels above 10-20%.

virtue3• 6 years ago

hydrogen is notoriously difficult to store. Being an atom "thick" generally means it leaks through containers regardless of what you try to do.

And I don't know if you've played the game "Oxygen Not Included", but creating liquid hydrogen is no easy task either.

A more dense energy storage substance (such as a hydrocarbon) would probalby be more efficient in terms of transportation / use / storage.

wtracy• 6 years ago

the whole point is to use excess power from solar/wind.

Thank you.

But converting that into carbon fuels that work directly in existing infrastructure and is effectively carbon neutral is a good option too.

This approach seems really underrated, at least for transportation.

Hydrocarbons still have the best energy density of the realistic options. We have a century of experience building ICEs with favorable power/weight ratios. Why throw all that away?

bit_logic3• 6 years ago

Too often have environmentalists let the perfect be the enemy of good. I understand why they feel that way, for so long have they fought against fossil fuel companies and other interests. They feel like if they give an inch, they will take a mile and climate change is too urgent. And so they oppose any transitional technology. They want to push for only perfect solutions like EVs and batteries.

But I want those environmentalists to sit down and think. Yes, climate change is urgent, and that urgency should make you stop asking for perfection. There are 1.4 billion cars in the world. Even a 100% ban today on ICE car production is not going to change that. Cars have an average usable span measured in decades. The projections for 2050 are catastrophic if carbon emissions don't go down.

Green tech has one big overwhelming victory right now, solar/wind. It's annihilating coal and will eventually defeat natural gas as well. We can take that victory and use it to make the existing cars and airplanes carbon neutral. If you care about climate change, why is this not more exciting than EVs?

skybrian2• 6 years ago

A problem with processes based on using excess power is that they use equipment inefficiently. If cheap power is only available for a quarter of the time then it would take 4x as long to pay for the investment in the equipment. Whatever scheme you set up to use excess power needs to be pretty cheap to make it worth running only a small part of the time, or it needs to be doing something especially valuable.

Compare to the strategy of locating somewhere that electricity is always cheap and running all the time.

bit_logic3• 6 years ago

Solar produces only during the day, but wind is at any hour. And these days, the idea of massive over-provisioning is being discussed to overcome the intermittent problem since solar/wind keeps getting cheaper and cheaper. The idea is simple, how to overcome the cloudy winter day issue? Simply overbuild a lot of solar/wind so it can still provide enough on a winter day. Then during summer, shutoff the excess power generation.

But what a waste of potential to do that! All that overbuilt power generation, simply turned off during summer. Batteries don't help here, it would store it, but then the question of what to do with it is still here.

If society goes the route of massive overbuilding solar/wind, then there's an opportunity to do something with effectively free power during summer. But it's ONLY during summer, so it needs to be something valuable that can also act as a energy storage.

Carbon fuel is perfect for this. Millions of ICE cars exist and are still being produced. Long distance airplanes will be carbon fuel based for a long time. And so many other uses. I think another option is water. Water can also be seen as a valuable resource that acts as energy storage. Use the excess summer power to fill up a near empty dam with desalinated water? Sounds like a perfect fit for regions like southern California or Arizona.

usrusr• 6 years ago

Yes, you can't do your price calculations based on 24/7 utilisation. But that's true for almost every other bit of technology as well. What's the average utilisation of a theatre? Of a plough?

carapace• 6 years ago

Bucky Fuller had the idea to just connect the world's electricity grids together. He called it "World Grid" I think.

ashtonkem2• 6 years ago

That’s more efficient, but difficult politically and logistically.

nine_k2• 6 years ago

Geography may also be a problem. Running a gigawatt cable from sun-soaked Australia anywhere in SEA is enormously expensive. Instead, packaging the energy into carbohydrates produced from waste water (cleaning it in the process) and waste CO₂ may be much more economical and convenient. You can likely produce the best quality Jet A fuel or octane 98 gasoline with little other fractions by tuning the synthesis process (unlike an oil well which gives you a mix you can't control).

Beside that, a transatlantic jet, let alone a Falcon 9, won't ever fly with battery power. You still need highly energetic fuels where power density is at a huge premium.

clouddrover• 6 years ago

Yes, it's worth making use of the excess power. The Orkney islands, for example, are using their excess wind and tidal power to produce hydrogen:

https://edition.cnn.com/videos/business/2020/03/06/orkney-hy...

adrianN4• 6 years ago

What's missing is a careful differentiation between doing what you said, storing excess energy, and approaches that are popularized, e.g. by carmakers unwilling to invest in R&D, where we keep on relying on hydrocarbons for things like transportation and heating and magically replace them with carbon neutral alternatives.

The first approach of using hydrocarbons as an energy buffer makes perfect ecological and economical sense and is most likely strictly necessary for a carbon neutral energy grid (barring battery breakthroughs), once we reach 60-70% renewable energy in our grids.

The latter approach however makes no sense at all, because we simply don't have enough space for wind and solar to feed our thirst for hydrocarbons with renewable power. The energy losses, both in the step creating the fuel, and in the step turning fuel to useful work, are just too great to fuel every car or heat every home in the world like that.

jfkebwjsbx• 6 years ago

How big are the losses to make such a big impact as to say there is not enough space for enough solar/sun farms?

99% or what?

leoedin2• 6 years ago

we simply don't have enough space for wind and solar to feed our thirst for hydrocarbons with renewable power.

I'm not sure if this is the case or not. To give some numbers:

Current global oil consumption is 54225 TWh, or 6.2TW [1] Current global solar panel generation capacity is 628 GW (2019) [2]. Median capacity factor maybe 25% [3] Current global wind power capacity is 650 GW [4]. Median capacity factor maybe ~37% [5]

Other renewables are unlikely to achieve the same growth as wind and solar, so can be ignored.

So we need to install 15x current renewables, times whatever the hydrocarbon creation process efficiency is, to produce all our annual oil demand.

Assuming a 50% process efficiency, we'd need to install 30x what we have now. That's a big installation, but it's not outside the realms of possibility. There's a lot of untouched desert in the world.

[1] https://ourworldindata.org/grapher/oil-consumption-by-region... [2]: https://en.wikipedia.org/wiki/Solar_power_by_country [3]: https://emp.lbl.gov/pv-capacity-factors [4]: https://wwindea.org/blog/category/statistics/ [5]: https://energynumbers.info/uk-offshore-wind-capacity-factors

D_Alex• 6 years ago

By golly, I agree! And I would agree even if I wasn't working on technology to achieve this.

Unfortunately, the article does not say how the zinc oxide nanoparticles will help with being able to use solar/wind power to produce syngas.

In fact it is not clear how these nanoparticles could actually be used to make an industrial catalyst. Current catalysts also use nanoparticles - on a substrate with enormous surface area/volume ratio, but these nanoparticles are created on that substrate.

I am curious about what the researchers plan as the next step.

08-152• 6 years ago

The article provokes these replies by prominently making this absurdly stupid statement:

This technology could be retrofitted to coal fired power plants.

No, it can't! The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available. It might work for a cement kiln, but not for a power plant.

I'm sure you know that. But the idiot who put a picture of cooling towers into the article clearly doesn't. He probably doesn't know the first law of thermodynamics, either.

twic2• 6 years ago

The power plant is run precisely when you don't have excess power to store. Conversely, you don't have concentrated CO2 when the power is available.

Unless you have some way of buffering the CO2. Biologically, this is what CAM photosynthesis does [1], and i have a vague memory of there being an industrial equivalent. Something like dissolving the CO2 in calcium hydroxide, to make calcium carbonate, then later on sparging it with hydrogen to recover the carbon?

[1] https://en.wikipedia.org/wiki/Crassulacean_acid_metabolism

credit_guy• 6 years ago

The application doesn't really make sense the way they explain it: use CO2 from a power plant to produce syngas. If the power plant burns methane, you might as well produce syngas straight out of methane, and short-circuit the step where you produce CO2. From the net energy usage point of view, you are better off (otherwise, you just found a recipe for perpetual motion).

Where this could make sense is energy storage. Say you are next to a large solar power plant, and you want to store the excess energy produced during the day and release it at night. Batteries are too expensive, pumped water requires some mountains, etc. With this, you store a quantity of CO2 in some tanks. At day you generate syngas and consume electricity, and store it in some other tanks. At night, you burn the syngas, get some of the initial electricity back, and store the CO2 back in its tanks.

pm902• 6 years ago

You’re correct but It still makes sense as a way to get existing power plant operators on board the green energy train. It’s probably cheaper to retrofit an existing plant to harvest the generated co2.

nine_k2• 6 years ago

This makes complete sense if you replace a power plant that produces electricity with an industrial process that produces heat, e.g. a blast furnace.

Then you can grab the waste CO₂ and turn it into something useful (ultimately liquid fuel, plastics, etc) by using the cheap solar energy, of which we often have a surplus at daytime.

This has the downside of only operating efficiently during sunshine, or needing a power transmission line from somewhere under sunshine currently (e.g. during local night).

ajuc• 6 years ago

How are they converting CO2 into H2+CO? Where is the hydrogen coming from?

thereisnospork• 6 years ago

Water. In a conventional CO2 electrolyzer (electricity + CO2 -> CO + O2) where CO2 is dissolved in water (plus salt) H2 is the standard byproduct per H2O + electricity -> H2 + O2. The concept of CO2+H2O directly into H2 + CO is neither novel nor useful, as dedicated green-H2 production is more efficient.

This is an example of 'meh' level work being puffed up.

gpm6• 6 years ago

Slightly offtopic, what's the easiest way to scrub CO2 from air (e.g. in a house) without using up consumable materials? Some form of pressure swing absorption?

atrus• 6 years ago

Probably a bunch of plants.

outworlder• 6 years ago

Under a lot of light, otherwise they would consume O2 as well.

gpm6• 6 years ago

Just in terms of numbers, you breathe out a kg of CO2 per day, you need to be growing more than a kg of plants per day to keep up with that.

That's a lot of plants.

marcosdumay2• 6 years ago

If you are concerned about indoor CO2 concentration, the answer is to ventilate the place.

No reasonable amount of plants will keep a house stable.

If it's just really curiosity, well, people have been scrubbing CO2 since space travel is a thing. Wikipedia was completely unhelpful to me, but I remember there is a mineral with high CO2 selectivity that you can simply push the air though it.

gpm6• 6 years ago

98% curiosity, 2% lack of faith in our long term ability to keep CO2 levels down to healthy levels (1000ppm is enough that we can detect minor negative effects... I have to wonder if really minor ones exist even at 400 ppm).

Wikipedia was similarly not useful for me. Scuba divers and the like apparently use a one-time-use non-regenerative mineral that absorbs CO2. The space station has something that regenerates but I haven't been able to figure out what.

adrianN4• 6 years ago

Get a large amount of calcium hydroxide in a watery slurry. That absorbs CO2 to form calcium carbonate. Take the carbonate outside and heat it up sufficiently to form calcium oxide and carbon dioxide. Add water to go back to calcium hydroxide.

swiley3• 6 years ago

Be careful with alkali metal hydroxides! They tend to be caustic and mixing them with water is exothermic (it can boil if you do it fast enough.) They will also react with aluminum, potentially violently and can ruin glass.

namibj4• 6 years ago

Not really without consumables, unfortunately. But it's easy and costs about 50-200$ per human and month when you just buy the required substance, granular CaOH treated with 1~2 NaOH (by pouring a concentrated solution of it over the CaOH), from Alibaba once a year. That stuff is e.g. used for re-breathers in anesthesia. CAS 8006-28-8 is the "magic" word/number.

The potential alternative, which would not use consumables, would be to just freeze it out. It's not _that_ hard, I believe an ammonia-based single-stage chiller should still suffice. Make sure to use counter-flow heat exchangers to not loose insane amounts of power. Handling the water condensation might not be that trivial, though.

swiley3• 6 years ago

Now you have caustic soda laying around and potentially being aerosolized, I’m not sure that’s an improvement.

mulcyber2• 6 years ago

Casual technical diver here. It's lime (maybe something else sometime, not 100%).

The process of making lime from limestone actually produces CO2, so it's use in CO2 scrubbers are more or less carbone neutral.

woodandsteel• 6 years ago

Synfuels are very important for saving the climate. Yes, we need to eventually move all transportation to batteries, and we now have the technology to do that with cars and increasingly with trucking.

But for ocean ships and long-range airplanes we are nowhere near ready for that. And hydrogen fuel cells are not nearly good enough. So at least for many years the only way to make some important forms of transportation carbon-neutral will be synfuels

Engineers find neat way to turn waste carbon dioxide into useful material

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