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Transportation Earth Science

Proposed CO2 Capture System Could Reduce Truck Emissions By 90 Percent 83

Researchers at the Swiss Federal Institute of Lausanne (EPFL) have come up with a new concept for capturing CO2 from truck exhausts which could reduce emissions by up to 90 percent. Engadget reports: In a paper published in the journal Frontiers in Energy Research, the researchers propose capturing carbon dioxide from a truck's exhaust pipe and turning it liquid, which is stored in a tank on the vehicle's roof. This liquid carbon dioxide can then be delivered to a service station where it can be reused in various ways, including being turned into conventional fuel.

The carbon dioxide capture works by first cooling the gases which are emitted from the exhaust pipe. Special absorbent materials developed at EPFL could separate the carbon dioxide from other gases like nitrogen and oxygen. When it is full, the absorbent material is then heated to extract the carbon dioxide, and heat from the vehicle's engine is used to compress the carbon dioxide and turn it into liquid. That liquid can then be stored in a box attached to the vehicle's roof until it can be deposited at a service station when the truck refuels. The system is more appropriate for large vehicles like trucks or buses than for cars as it is rather bulky, requiring a 2-meter-long capsule and weighing 7 percent of the total payload of a truck. However, the researchers calculate that 90 percent of carbon dioxide emissions could be recycled in this way.
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Proposed CO2 Capture System Could Reduce Truck Emissions By 90 Percent

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  • 7% total payload (Score:4, Interesting)

    by SeaFox ( 739806 ) on Tuesday December 24, 2019 @02:24AM (#59552958)

    I can hear the logistics companies readying their lobbyists already.

    • How much, electric or mechanical I don't care, load is going to put the compressor system into the egine?
    • by guruevi ( 827432 ) on Tuesday December 24, 2019 @08:46AM (#59553440)

      The system is totally impractical. It will increase fuel consumption by 7% and basically add on about 2 tons of weight during the consumption of a fuel tank (most of the weight in CO2 comes from the oxygen in the air) in a small truck. Then youâ(TM)ll have to store and transport on your average fuel station basically every 30 minutes about an 18-wheeler worth of this stuff where the CO2 will be cracked somehow, which requires a LOT of fuel in and of itself.

      • by Billy the Mountain ( 225541 ) on Tuesday December 24, 2019 @10:19AM (#59553632) Journal
        Right, it's been a while since I did the calculation but I just looked it up: https://www.engineeringtoolbox... [engineeringtoolbox.com] For diesel you get 3.15 pounds of CO2 per pound of fuel burned! I was thinking it was like 2:1 but it's 3:1+! So you start out with 100 pounds of fuel in your tank, burn it and you wind up with 284 pounds of CO2 on your roof. (90% of 315 is 284). A LOT of extra weight to carry, plus you would have to worry about how the truck's center of gravity is adversely affected if the CO2 is indeed stored on the roof.
        • Yeah, that 3:1 ratio can be a bit surprising, but it makes sense if you think about it - hydrocarbons are almost pure carbon by weight since hydrogen weighs almost nothing. Meanwhile, CO2 attaches two oxygens to every carbon, and oxygen is slightly heavier than carbon (the increase almost perfectly balancing the loss from hydrogen in long-chain hydrocarbons)

      • If by impractical, you mean much less efficient, and less profitable, then yes, it's impractical. However, losing a portion of profit to save humanity, is a logical choice.
  • by rossdee ( 243626 ) on Tuesday December 24, 2019 @02:24AM (#59552960)

    To liquify CO2 you have to cool it a lot. Where do you get the energy to do that?

    • Either that or compress it (as mentioned in the summery, five words to the left of where it says "liquify")

      • To eight megapascals. That's not even a great deal of pressure. Either way though, significant energy use.

        • Perhaps the energy could be recovered when braking and used to compress the gas. Basically engine braking like some trucks already do but instead of compressing air and releasing it, compress the CO2 and put it in a tank. That said, this probably won't work that great on long highway routes.

          • EGRs cause enough trouble as they are, that system does not need any more complexity, IMO the best option would be installing a second compressor that compresses the exhaust behind the turbo, the air compressors they use for the braking system are belt driven, the biggest issue would be taking care of the soot, the soot clogs everything and causes the problems you get with the EGR, combine that with a compressor, and you have an absolute mess of black dust that's going to prevent the system from working.
          • Probably easier to simply compress it on the road, and then recover the energy used when emptying the tank.

        • It's about 1200psi. About 10x the average pneumatic system. Air compressors that put out that kind of pressure are do it at low volume, they are uncommon, expensive and high maintenance. And now you're asking it to suck up diesel exhaust, which presents another set of problems. No matter how well filtered the exhaust gas is you're going to get diesel and motor oil soot, which is sticky and loves to plug up small passages, and is abrasive to the sort of seals likely to be used in a compressor.

          • by jwdb ( 526327 )

            It's also about 1/2 to 1/3 of the average pressure of a scuba tank, and scuba compressors are both common and widespread. It is true that these are lower volume than what's being proposed here, by about 2 orders of magnitude off the top of my head. They also are expensive, but scuba compressors have requirements for cleanliness (don't poison the divers with compressed fumes) that go beyond what I expect would be required here.

            Can't comment on soot, as I don't know how easy or hard that'd be to deal with.

    • by Anonymous Coward
      Ideal Gas Law

      T=pV / nR

  • How much energy is used to make this melted dry ice? Include EU taxes on Diesel and other road taxes. I'm sure it is a lot and less efficient than direct alltenator used to coll refrigerated loads. Now add up the weight and cost of this gizmo on a per ton per KM basis. In short as impractical as a solar powered tanning light.
  • why trucks? (Score:1, Insightful)

    by Anonymous Coward
    Global CO2 emissions of all the vehicles is insignificant next to the major contributors. The act of punishing Volkswagen probably put more CO2 into the atmosphere than their cheating diesels. Why would these intrepid inventors suggest applying their innovation to trucks, instead of coal power plants, airliners, supertankers, glass factories, cement factories, et al.? We're going to fix the dam by plugging the pinholes?
    • Re:why trucks? (Score:5, Informative)

      by ShanghaiBill ( 739463 ) on Tuesday December 24, 2019 @03:58AM (#59553062)

      Global CO2 emissions of all the vehicles is insignificant

      Trucks are about 6% of global CO2 emissions. That is significant.

      • Comment removed based on user account deletion
        • ...I'd like to see some boring electric trucks with a full length bed that can be used for work. I'd need about 100 mile range....

          The Tesla Semi should fit the bill, with a promise of between 300 - 500 mile range, 4 motors and 2 kWh/mi.
          And you know Elon Musk, that Semi looks fantastic.
          Tesla keeps pushing its production date back. I think it's 2020 right now - you know Elon.
          https://www.tesla.com/semi [tesla.com]

    • Re: why trucks? (Score:4, Informative)

      by im_thatoneguy ( 819432 ) on Tuesday December 24, 2019 @04:03AM (#59553064)

      The VW emissions weren't about CO2 it was good old fashioned lung destroying toxic pollutants.

    • It's usually the green crowd I have to explain this to. But I guess it's not surprising others have the same misunderstanding. The first place you want to install fuel saving / emissions reducing technologies is in places where the least amount of effort will yield the greatest benefit. For vehicles, this is synonymous with low MPG - if an emissions reduction technology reduces emissions by x%, then you want to install it first on the vehicles which use the most fuel getting from point A to point B. If,
      • by sinij ( 911942 )
        You also need to explain consequences of additional costs in transportation. Trucking operates on very lean profit margins - there isn't funds available for additional equipment and waste disposal. More so, loss of cargo space due to additional capture and storage equipment is not trivial.

        I think it is infeasible to substantially optimize truck emissions without also notably increasing costs of shipped goods. I think shipping by rail and increasingly electrifying rail lines is what should be done - but suc
      • Ironically, the best place to put a hybrid drivetrain (to yield the greatest reduction in fuel consumption) was in SUVs. Except the environmentalists mocked car companies when they tried to do that in the early 2000s, and got hybrid SUVs killed for a decade.

        lol no. The first production hybrid SUV was a Dodge Durango that cost $85k+ depending on options. The cost killed hybrid SUVs for a decade. Batteries are much cheaper now.

    • by N1AK ( 864906 )
      Vehicle emissions are anything but insignificant, and notably are one of the few areas emissions are increasing in the West rather than falling. Your analogy about dams was fitting if you completely swapped your lists around.
    • And city air quality is bad enough to have a measurable negative impact on public health.
    • ...Why would these intrepid inventors suggest applying their innovation to trucks, instead of coal power plants...

      Could be because:
      1 There already is technology to recover carbon dioxide from coal power plants https://www.sciencedirect.com/science/article/pii/S1876610209001726 [sciencedirect.com].
      Humble guess, but this tech should work on any factory with a flue emitting enough carbon dioxide to make it worthwhile.
      2 The article has a link that references data showing carbon dioxide from road transportation was significantly higher than anything else in Europe, with cars taking over 60% of the dirty glory, and trucks about 40%. It

  • Why place these on trucks when you can install them at power plants where mass and volume do not cause problems. Just switch the trucks to electric and have an electric infrastructure that minimizes CO2 emissions. This way cars benefit as well.
    • Re: (Score:1, Insightful)

      Because you'll never get trucks that don't run on diesel, electrics are struggling to fight with gasoline powered ICE ranges, diesels are entirely on another planet in that regard.
      • Tesla semi has a range of 800 km. Volvo is apparently releasing one at about the same time with a 300 km range. And Cummins is preparing one with a 450 km range.

        These are first generation products. With some more time and a drop in battery prices, almost all trucks will go electric purely for the cost savings. And it will probably take less time for this to happen then it will take to get CO2 collection devices working and installed onto trucks. But CO2 collection could work quite well on ferries an

        • I'll believe Tesla whem I see them rolling, Volvo is a better gauge of how things are going to be, keep in mind that they're going against semis that consume 30l/100km with tanks that hold up to 1400 liters, let's assume that the average tank holds 600L, that gives the semi a range of 2000km.
          • by NagrothAgain ( 4130865 ) on Tuesday December 24, 2019 @09:27AM (#59553526)
            A quick google search shows the nonstop range of a typical 18 wheeler to be around 2000 miles. What Tesla is targeting is roughly how far a semi can go in 8 hours, which is when the driver is supposed to pull over and sleep. It's also far more likely that we'll see electric used more for local distribution as opposed to long haul trucking.
            • It's also far more likely that we'll see electric used more for local distribution as opposed to long haul trucking.

              That also removes all those point sources from congested urban areas.

      • by cnaumann ( 466328 ) on Tuesday December 24, 2019 @09:16AM (#59553496)

        (Most) trucks are already range-limited by their drivers. You do not have to produce an electric truck that competes with ICE trucks on range, you just have to produce one that is less limited than the driver. That can be done.

        • by zvar ( 158636 )

          So we are talking a 550-600 mile range then as that's an "average" day. Drivers are limited to 11 hours of driving a day so that's only an average of 50-55 MPH.
          If one is driving out west with speed limits of 75-80 that's actually a slow average....

  • A 1 kg of fuel coming from the tank (containing carbon, C), reacts with another 2.3 kg of oxygen (O2) coming from the air.
    The result is 3.16 kg of CO2 per each 1 kg of fuel burnt (or 2.85 kg / kg with the claimed 90% efficiency).

    How do you store that?

  • So if combined with a carbon-neutral fuel source (ethanol perhaps), could this be used to actually remove CO2 from the atmosphere overall? Grow corn, remove CO2 from the air. Make ethanol, giving some of the CO2 back in the process. But then when it gets burned, the CO2 doesn't just go back into the air. Even with 10% of it escaping the system, the sequestration of the other 90% just might make this a practical way to fuel long-range/high-availability vehicles and use them as a network of carbon scrubbers a

    • Corn ethanol is like 10% energy-positive. It would make more sense to use algae-based green diesel, or biodiesel.

      Corn ethanol also is grown continuously (without crop rotation) and destroys topsoil, so it's selling out the future for profit today.

  • One can always improve efficiency and fuel economy by making it lighter.
    Instead lets make it Heavier and clunkier so it will polute less!

    Attacking the symptom before making it a lot better is not the the way to go. There are better aproaches: Mack jet eletric truck [newatlas.com]
    There is a lot of room for deployment of simple tech like aerodynamic skirts and foils that can signigicantly improve fuel efficiency in semi-trailers on road use.
    It must be economically attractive, or else.

  • Or are there existing better solutions?

  • by Computershack ( 1143409 ) on Tuesday December 24, 2019 @08:23AM (#59553384)
    "weighing 7 percent of the total payload of a truck" Not happening. When we don't even carry spare wheels anymore to save weight for paying loads they're not going to give up 7%.
    • by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Tuesday December 24, 2019 @11:07AM (#59553756) Homepage Journal

      I see lots of trailers carrying spare wheels, still, though I rarely see trucks carrying them. That's one of the big drawbacks of super singles, in fact. When they blow out they usually destroy the wheel, so not only do you have to come up with another super-expensive super single, you also have to come up with another expensive wheel. So if you run them, you pretty much have to carry a spare.

      Super singles supposedly reduce fuel consumption by somewhere between 2.9% and 7%. But in general they are considered to only be worth the hassle for short-haul trucking where the fleet manager can send out spares on a pickup truck.

      I can however envision a future where CO2 emissions are taxed, in which case giving up 7% of the payload capacity might actually be a good trade.

  • Jethro Bodine once invented a pollution free vehicle but the gizmo took up the whole back of the truck. Jed needs to have along talk with that boy sometime.
  • Capture it, sure. Now what? It isn't magically gone. Transporting it around and putting it somewhere for indefinite storage would be an immense challenge.
    • by PPH ( 736903 )

      Sell it. To greenhouses and vertical farms [wikipedia.org]. CO2 and NO2 (if we could capture that) are critical inputs for plant growth. And we are going to have to do something to boost that if we want to move away from beef consumption. We only have so many Amazon rain forests to clear for the necessary soya needed to feed the world.

      • You're implying that we'd have to grow more vegetation if we are to stop eating beef. Just what do you think cattle eat?
        • by PPH ( 736903 )

          Just what do you think cattle eat?

          Grasses and clover. Stuff we can't eat. And stuff that doesn't require wiping out biodiversity just to plant human veggies.

  • Until Coal power plants are doing recapture at scale, nothing else makes sense. They have fixed infrastructure, don't have to waste fuel just moving the result around for no good reason, and have the economy of scale. Next... ships, as they generate enormous quantities of pollution per ship, and dock at discrete locations that can be equipped to offload the co2. Far down the list will be trucks. This is just people trying to look like they are making advancement for funding. If carbon capture of coal p

  • With enough energy, you can do most anything. Why not just dissociate CO_2 into carbon and oxygen, release the oxygen into the atmosphere, and use the carbon to make pencils and airplane wings. Yeah, you can send the Peace Nobel right here.
    • by radl33t ( 900691 )
      this is effectively what will sustain the hydrocarbon industry and transportation fuels with high penetration wind, solar, and maybe nuclear power. These schemes go by many names, one is power to gas (P2G). It's technically easy and energy and cap ex is already cheap enough to do it on a large scale for transportation fuels. Solar gasoline costs about 2 $/gallon to produce. Stuff it with a 50% profit for all the middlemen, including government taxes, and we have energy costs that everyone can deal with. Fif
  • When the proposed solutions rely on perpetual motion machines to function, the claim that seriously scientists agree does not pass the laugh test. Newsflash idiots: compressing the CO2 to 80 atmospheres, even if you have a magic zero-engine-power-lost way of separating it from the rest of the exhaust, is going to eat up whatever power is coming out of the engine. So not only will your truck weigh more, it will have less power to the drive wheels. And to make up for it, you will need to guzzle more gas to th
  • This is yet another one of those stupid stories about unworkable CO2 capture systems that more than likely add to overall CO2 emissions than reduce them. Also, pointless because almost nobody's going to implement them even if they work. For better or worse, electric vehicles are the future now. Let's hope all that extra electricity will be generated from renewables & actually make a difference to overall CO2 emissions.

    Now we can start dealing with the more pressing issue of greenhouse gas emissions from

    • Some people would rather see millions of climate refugees starve to death than cut down on their meat & dairy consumption.

      We also need to give proper consideration and care to the millions of refugees from the planet Mars, because their planet is no longer habitable.

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