Ethanol FROM CO2 - New cataylst process - Page 1
Forum section: electronics / general

author: VulcanBB18
author_rank: Contributor
timestamp: October 18, 2016, 10:42:01 pm
content: This looks quite promising!I like serendipitous discoveries like this one. I hope it scales up!https://www.sciencedaily.com/releases/2016/10/161012183520.htmcheers,

author: rdl
author_rank: Super Contributor
timestamp: October 18, 2016, 11:15:55 pm
content: Shouldn't the thread title read "EthanolfromCO2"?

author: VulcanBB18
author_rank: Contributor
timestamp: October 19, 2016, 12:25:34 am
content: Whoops! That's what happens when I post pre-coffee wake-upthanks guys

author: Macbeth
author_rank: Super Contributor
timestamp: October 19, 2016, 12:37:08 am
content: CO2 has always been a happy byproduct of ethanol production, at least back in the day I used to homebrew. To turn that fizz into ethanol? It's the holy grail...

author: raptor1956
author_rank: Frequent Contributor
timestamp: October 19, 2016, 02:15:52 am
content: If this can be scaled up it could mean big things for coal. As just about the worst producer of CO2 coal is the boggy man and if that levels can be dramatically reduced or near eliminated then I don't know that its other vises would preclude it vis-a-vis other carbon fuels. It would make a lot of people in West Virginia very happy...But, since all the fuels we have come from the Sun or solar processes solar energy is ultimately the most efficient energy around. Even at 15%, the starting point these days, solar voltaic is more efficient than any of the fossil fuels that require the Sun to produce the precursors (plants, plants->animals) that eventually (tens of millions of years) and with generally low efficiency become coal, oil, etc. None of those fossil fuels are anywhere near 1% efficient in converting solar energy into usable energy.Brian

author: VulcanBB18
author_rank: Contributor
timestamp: October 19, 2016, 03:32:11 am
content: Yes, all fossil fuels are effectively "stored sunlight" however one of the problems with electric vehicles in particular is energy storage - even the best batteries still don't approach liquid hydrocarbons in terms of energy density. In terms of coal, I don't know if this technology is viable as a "CO2scrubber" for things like coal power stations (which we have plenty of in Oz).If this process allows us to make convenient liquid fuels from a waste product (CO2) and some renewable energy input (eg. Solar/thermal/etc), then we can start to displace the heavily reliance on fossil fuels, the liquid ones particularly.Save that oil for making exotic plastics, not burning in our enginescheers,

author: edavid
author_rank: Super Contributor
timestamp: October 19, 2016, 04:16:27 am
content: Quote from: VulcanBB18 on October 19, 2016, 12:25:34 amNow make it CO2instead of C02.

author: Holmes34
author_rank: Contributor
timestamp: October 20, 2016, 08:18:22 am
content: Quote from: VulcanBB18 on October 19, 2016, 03:32:11 amPeople always quote this energy density thing, but this is a pretty moot point as I'd venture to say above 70% of automotive road journeys probably fall into the range limitations of modern EV's. Additionally taking only the energy density of the fuel and not the equipment to extract and convert that fuel into usable energy (a moving car) is probably a more accurate assessment of a fuel's usefulness for transportation, otherwise we'd be pushing for nuclear engines!Charging time and vehicle price are probably the only current things holding back EV's in terms of widespread use (At least the only practical real issues, public perception is a whole other kettle of sharks). Your second point about using these hydrocarbons for plastics is pretty much hitting the nail on the head. The current state-of-the-art in bioplastics is honestly decades behind EV's in terms of competitiveness.

author: tszaboo
author_rank: Super Contributor
timestamp: October 20, 2016, 08:30:38 am
content: Quote from: wraper on October 20, 2016, 08:26:05 amAFAIK they need electrical current to reverse the process. So we can make a Rupe Goldberg machince, converting CO2 to Vodka and backwards, but it does not solve the fundamental issue.On the other hand, if they make a solar panel, attach a etanol machine to it, and make sure, that thirsty university students dont raid it, it can be just the thing we need to avoid global climate collapse.

author: wraper
author_rank: Unknown
timestamp: October 20, 2016, 08:35:16 am
content: Sounds like "green" BS. As it's a complete opposite of burning an ethanol, at least the same amount of energy would need to be spent to reverse the process => there is no point doing it. Well unless you have unlimited amounts of "green" energy for conversion and want to store the CO2 underground forever in the form of ethanol. Or in your stomach, LOL.NANDBlog was fast to reply before I deleted the post shortly after the posting to edit it a bit.

author: raptor1956
author_rank: Frequent Contributor
timestamp: October 20, 2016, 08:39:02 am
content: Quote from: Holmes34 on October 20, 2016, 08:18:22 amEnergy density matters for planes in particular and although the vast majority of days driving require no more than a typical EV car's battery range there are days when you need 3X what the highest range Tesla can provide. You can't average these things anymore than a conventional car can average HP requirements and conclude a car needs no more than 20hp.My point was that ALL the energy we use comes either from the Sun or solar processes (heavy elements) and that the fossil fuels and all other non-solar energy sources are hugely inefficient compared to even the cheap 15% solar cells we have today. Oil, for example, comes from organic material than gained it's energy from the Sun directly or indirectly by eating things that did. The efficiency with which the organic materials sequester energy is much less than 1% and then you have to wait many millions of years to get oil. With solar, you get 15% or more instantly -- no waiting.The big drawback to solar is storage and while batteries are a way to handle that it will be a while before the lifespan of battery packs are practical. But, since about 2/3 of energy use is during daytime even if there was no storage solar could provide 2/3 of our energy needs not counting planes.I expect that 50 years from now, if we haven't killed ourselves off by then, we will be producing about 50% of our total energy needs with solar panels on our roof with another 35% coming from large utility scale solar projects. Some of the energy produced from the large solar projects will be used to make clean fuel for things like planes. I would bet that by then the cheap solar cells will be at least 25% and probably more like 35% efficient. A home with 100m^2 of 25% solar cells could produce on an average day about 75-100kWHrs or energy and that would fuly power the average home and leave perhaps 25kWHrs for a couple cars.Brian

author: Halcyon
author_rank: Unknown
timestamp: October 20, 2016, 08:50:58 am
content: Quote from: VulcanBB18 on October 19, 2016, 12:25:34 am0942H is pre-coffee wake-up time? ;-) I think I've had my first coffee at 0445H most days.

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2016, 11:58:31 am
content: If this is efficient and scalable it could be huge. Energy storage is the big problem with the large scale use of wind and solar. If we can take all the surplus energy from those sources in peak generation periods, and efficiently store it as alcohol from atmospheric CO2, our existing fossil fuel systems can continue to be used indefinitely, with no net carbon release to the atmosphere.

author: Kilrah
author_rank: Unknown
timestamp: October 20, 2016, 12:24:40 pm
content: Quote from: Holmes34 on October 20, 2016, 08:18:22 amDoesn't change a thing, even if you CAN do most of your travels with an EV people don't buy one if they can't do that occasional long trip with it which requires them to either own a 2nd vehicle or to rent one for way too many $$. Thresholds vary, but I'd say if you know it won't make it >10% of the time most wouldn't do the jump.Quote from: wraper on October 20, 2016, 08:35:16 amOf course there is, to be able to use solar-based energy in things that can't incorporate solar sources or sufficient energy storage. Or that can, but where it would be so much more practical to keep an existing system.E.g a passenger plane won't run on solar-charged batteries in a LONG time, but it could run on solar-generated liquid fuel.Just like being able to run a car on liquid "green" fuel would allow reducing fossil fuel dependency MUCH quicker than replacing the entire car with an only mildly apopropriate solution completely different solution i.e. electric+batteries.

author: mac.6
author_rank: Regular Contributor
timestamp: October 20, 2016, 12:37:40 pm
content: Quote from: wraper on October 20, 2016, 08:35:16 amYou can wrap this discovery in green BS sure, but it's a very interesting discovery: 63% yield to convert CO² to ethanol is quite high given it's a fresh discovery.Now if this can be reverted, it can gives you direct electricity from ethanol at highest yield without any precious metals...

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2016, 12:43:17 pm
content: Quote from: mac.6 on October 20, 2016, 12:37:40 pmI'm not sure what they mean by that 63%. It seems like they mean they get 63% of the potential ethanol, but they might mean its 63% energy efficient. Whichever they mean, its not bad for a first pass.

author: helius
author_rank: Super Contributor
timestamp: October 20, 2016, 01:01:45 pm
content: In chemistry yield usually refers to the percentage of a chosen starting material that was converted to the target compound. So 63% yield means that 63% of starting CO2 was converted to ethanol. Energy use is not accounted for in chemistry papers.The yield is a way to quantify how selective the reaction is, since more side-products lower the yield. Some of the product is lost during purification, which also lowers it.

author: rs20
author_rank: Super Contributor
timestamp: October 20, 2016, 01:17:03 pm
content: Sunlight ---Solar panel----> ElectricityElectricity + CO2 ----This discovery-----> EthanolorSunlight + CO2 -----Corn plant-----> EthanolI mean, I know it's more complicated than that. But I do wonder about the entire-lifecycle-analysis side of this.Obviously a discovery worth pursuing, no doubt.

author: Kilrah
author_rank: Unknown
timestamp: October 20, 2016, 01:19:58 pm
content: You can put solar panels in otherwise unusable locations, but corn needs space that could/should be used for something else...

author: helius
author_rank: Super Contributor
timestamp: October 20, 2016, 01:24:43 pm
content: The trick is that you need a CO2 supply. So there are not very many places that would be suitable.

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2016, 01:29:41 pm
content: Quote from: helius on October 20, 2016, 01:24:43 pmThat depends on the concentration of CO2 that they need. The ideal thing would be that they have something that works like photosynthesis, extracting the small CO2 content of the atmosphere.

author: helius
author_rank: Super Contributor
timestamp: October 20, 2016, 01:38:46 pm
content: A catalytic reaction that converts 2CO2+ 3H2O = C2H6O + 3O2can only produce 200 ppm ethanol from the 400 ppm CO2 in the atmosphere. Distilling such a dilute fuel would be prohibitively inefficient.

author: coppice
author_rank: Super Contributor
timestamp: October 20, 2016, 01:48:03 pm
content: Quote from: helius on October 20, 2016, 01:38:46 pmWhy would the fuel be dilute? Is some other reaction producing a liquid result going on in parallel?

author: helius
author_rank: Super Contributor
timestamp: October 20, 2016, 02:04:46 pm
content: Yes, it is possible that ethanol is also a reactant and you would get heavier products if the CO2 runs out.I don't know the mechanism of this reaction but the description in the web article suggests there are many possible products.

author: Cerebus
author_rank: Super Contributor
timestamp: October 20, 2016, 04:06:30 pm
content: Quote from: helius on October 20, 2016, 01:24:43 pmBreweries, bakeries, the list could be quite long; but if I had somewhere that produced beer, bread and fuel for my car I'd have a goodly proportion of the things that I think are essential in life.

author: Cerebus
author_rank: Super Contributor
timestamp: October 20, 2016, 04:16:22 pm
content: Quote from: helius on October 20, 2016, 01:01:45 pmHere's the abstract of the actual paper that the article is about:QuoteSo foryieldsubstituteFaradaic efficiency.Actual paper ishttp://dx.doi.org/10.1002/slct.201601169.Edited to add:This is an example of something that really ticks me off - mangling of clear information in a scientific story as it gets written up by a journalist even in decent publications such as New Scientist, Scientific American, or in this case Science Daily. Don't get me started on medical research as reported by the likes of the DailyFascistMail*.*The Daily Mail were enthusiastic supporters of the British Fascist Movement even after it had become clear to everybody else what Fascism, Hitler and Mussolini were really all about. Their approach to politics these days is just as nuanced as it was then and I consequently take every opportunity to remind the world quite how sound the editorial opinions of this organ have been proved to be.

author: helius
author_rank: Super Contributor
timestamp: October 20, 2016, 05:23:54 pm
content: That makes it a lot clearer, thanks for reading the paper so I don't have to!63% Faradaic efficiency is low compared to a Li-ion cell, but not terrible for many electrochemical reactions.The emphasis in the paper seems to be on a new area in CO2chemistry and not as a "green energy" project.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 20, 2016, 05:33:48 pm
content: Quote from: helius on October 20, 2016, 05:23:54 pmAnd unlike batteries, if you need more storage capacity, all you need is a bigger tank!

author: raptor1956
author_rank: Frequent Contributor
timestamp: October 20, 2016, 07:56:02 pm
content: Did they mention its use as a scrubber for things like coal fired power plants?Brian

author: tszaboo
author_rank: Super Contributor
timestamp: October 20, 2016, 08:08:38 pm
content: Quote from: raptor1956 on October 20, 2016, 07:56:02 pmI'll try to explain it in a simple way.C+O2 = CO2 generates 1 Energy.CO2 + H2O = alcohol requires 3 energy.

author: Cerebus
author_rank: Super Contributor
timestamp: October 21, 2016, 12:46:02 am
content: Quote from: NANDBlog on October 20, 2016, 08:08:38 pmA clearer way of putting it, is to to say that scrubbing CO2using a process like this would consume at least as much energy as was produced by the process that liberated CO2. Add inefficiencies and you end up with a net energy loss.To put some hard numbers on it:- Every megajoule of energy obtained from burning coal* liberates 2 mols of CO2. Every megajoule of energy obtained from burning ethanol liberates 1.6 mols of CO2- a perfect process for making ethanol from CO2would use the same amount of energy. That is, you can only pack away 1.6 mols worth of CO2from coal with the energy liberated in creating 2 mols of CO2. Thus you're already on the losing side of the energy equation before any process loses.*The assumption used where I lifted the figures from is that the C:H ratio in the coal burned is 1:1 which is about right.

author: Someone
author_rank: Super Contributor
timestamp: October 21, 2016, 02:52:41 am
content: Quote from: mikeselectricstuff on October 20, 2016, 05:33:48 pmRange scaling of vehicles is discussed in "Sustainable Energy – without the hot air" and the incremental weight/size of more batteries eats into the energy efficiency of electric cars somewhere around 500-700km range, if you need to go further without taking on more energy then the fossil fuels are superior.Quote from: Kilrah on October 20, 2016, 12:24:40 pmIt really depends where you live, rent/hiring vehicles is commonplace and cost effective in Australia but it still doesn't make sense to jump to an electric car because of the relative fuel costs:https://www.eevblog.com/forum/chat/problems-if-we-all-had-tesla-cars/msg705793/#msg705793Otherwise I'd be building a small electric car with a range of 200km and renting something else as needed. Run the maths yourself, its not possible to make such broad statements on a world scale.