Scientists turn carbon emissions into usable energy - Page 1
Forum section: electronics / general

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 23, 2019, 03:51:21 am
content: I don't understand where the energy is coming from here.https://www.eurekalert.org/pub_releases/2019-01/unio-stc011819.php?fbclid=IwAR2f9dWrsDP8GDUKWDLwnE42pnQFK62Qj04gTtkQQdC1ByaUXKfiNA3rAF0Any ideas? Is it real?Article from Sandia National Labs requires energy to split CO2.https://www.scientificamerican.com/article/splitting-carbon-dioxide/

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 23, 2019, 04:13:57 am
content: Good thing we can dig metallic sodium out of the ground...So, it turns Na, H2O and CO2 into NaHCO3 and H2. We can do that by dropping it into water and waiting a bit (albeit with a bit less electricity generation, and a lot more explosions). No, it is not in any way meaningful or useful.Tim

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 23, 2019, 03:40:39 pm
content: Quote from: T3sl4co1l on January 23, 2019, 04:13:57 amThanks for the input T3sl4co1l.I was hoping someone might help with the energy flow. Sodium is available in salt. So I guess the energy to separate the Na from the salt is an energy input. Then some part of the energy is recovered in electricity and H2. Of course there still is a net loss of energy but how much and what is the cost?

author: coppice
author_rank: Super Contributor
timestamp: January 23, 2019, 03:43:46 pm
content: When anyone comes up with a "plan" that turns CO2 into fuel, remember that CO2 is ash in gaseous form. Only a massive injection of energy will turn ash back into fuel.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: January 23, 2019, 11:16:31 pm
content: Quote from: coppice on January 23, 2019, 03:43:46 pmI guess we don't have an electrochemist around here.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 23, 2019, 11:59:55 pm
content: Quote from: ahbushnell on January 23, 2019, 03:40:39 pmIdunno, look up the commodity cost of sodium metal and compare that to other "metallic energy" products like magnesium and aluminum.Reminder that those metals are already not economical to use as energy storage media, although that's partly because they suck, chemically (aluminum batteries exist, sure, but they clog up with Al(OH)3 painfully quick).Probably, sodium being a somewhat more specialty item than the latter, it's not smelted so close to cheap energy sources (usually hydro), nor in as great quantity, so the dis-economy of scale adds to its cost, as well as the energy required to produce it.I'd be much more excited for sodium batteries. If it can be made to work effectively without heat (currently there's asodium sulfur battery, Al2O3 electrolyte, that operates at molten temperatures -- modest, 150C or so), it'll be safer, and use far more abundant materials (assuming the membrane isn't exotic) than lithium cells, at the price of a modest drop in energy density compared to lithium. Well worth it for huge mass production, as needed for EVs and grid storage.Quote from: ahbushnell on January 23, 2019, 11:16:31 pmFYI, I know probably as much electrochemistry as anyone here.Tim

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 24, 2019, 12:00:47 am
content: Quote from: coppice on January 23, 2019, 03:43:46 pmIt has already been done - biofuels.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 24, 2019, 12:43:31 am
content: Dunno if we really need an electrochemist here or rather an alchemist.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 24, 2019, 01:05:14 am
content: Quote from: NiHaoMike on January 24, 2019, 12:00:47 amYeah -- what I'm excited to see develop, in this domain, isefficientelectrochemistry, or photochemistry, converting CO2 + H2O into useful feedstocks plus oxygen.We already have such an end-to-end process-- however, it's embarrassingly inefficient, a percent or two, no better than plants are.There are some processes for reducing carbonates into formate, a key step. (On heating, formate decomposes to CO + CO2, the CO of which can be used to reduce other things, and ultimately make any other feedstock. Though that's kind of heroic to go through, and hence inefficient.)A catalyst that reduces carbonate (or CO2) down to, say, methanol, would have a product that is directly usable as fuel, and easily integrated into existing synthesis chains.Methane would be a close second. It absolutely sucks to transport, but is about as usable, and can be oxidized one tick back up, to methanol, which is easy to transport.The purpose, by the way, is again not to "make" energy -- that is manifestly impossible here -- it is to transport energy, in the most economical way possible. BatteriesSUCK.No ifs, ands or buts about it. There is very good reason why hydrocarbon fuels will never go away. We can't possibly try to compete with them, we must harness them.Note: currently, anything producing methane, and by extension methanol, needs to compete with natural gas, which is one hell of a challenge. Not only that, but methane is currently only economical from high pressure wells -- it's distributed at 100s of bar, where its gaseous energy density iscomparableto its heat value! At those pressures, it pumps itself through purification and distribution systems, no external power required.The best possible dream, would be a carbon fuel cell, that is reversible, so can be charged, capturing CO2 and H2O from the air and producing fuel; and which does the opposite in reverse to produce electrical energy. This would perform about an order of magnitude better than any battery we can possibly come up with, and be compatible with existing hydrocarbon infrastructure with none, or minor changes.I'm not so optimistic to expect that to happen even in the next half a century, but the first one can, and I think will, happen. If I were to guess, I'd guess some of the catalysts will be figured out in the next decade, with mass roll-out in the next decade or two after that, driven by the rising costs of petroleum. You will know it has arrived, when we have indirectly-solar-powered jet transportation dominating the skies! (Also assuming solar power -- or anything else reasonably carbon neutral, like nuclear -- expands to fill the then-massive electrical demand. There are also direct thermal routes known, like the iodine process for producing hydrogen, which has been suggested as an application of mid-level waste heat from high-level power stations, e.g., high temp coal or natural gas, pebble bed nuclear, etc.)Tim

author: coppice
author_rank: Super Contributor
timestamp: January 24, 2019, 09:29:21 am
content: Quote from: T3sl4co1l on January 24, 2019, 01:05:14 amMethane is one of the main heating fuels. People have no problems storing and distributing it today. It would be reasonably easy to store large amounts, to ensure there is fuel during extended periods when little new fuel is being produced. Compressed natural gas (CNG) is widely used as a transport fuel in many places. There may be fuels which are easier to work with, but CNG is a very well established fuel, with all the necessary storage and distribution techniques in place.

author: nctnico
author_rank: Super Contributor
timestamp: January 24, 2019, 01:44:58 pm
content: Quote from: coppice on January 23, 2019, 03:43:46 pmFortunately plants and algea are doing that on a large scale. Someone's trash is someone else's treasure.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 24, 2019, 04:23:11 pm
content: This is simple chemistry. Lookup LEO and GER. H2O and CO2 are the waste product of combustion. The oxygen is fully reduced. It takes energy to break those oxygen bonds. That’s what plants do with Chlorophyll and suns energy. Look up the Krebs cycle.

author: apis
author_rank: Super Contributor
timestamp: January 24, 2019, 09:25:29 pm
content: I think the idea of bio engineered oil producing algae/bacteria sounds very promising, might even be able to farm ocean living species which means you could use seawater as growing media.

author: nctnico
author_rank: Super Contributor
timestamp: January 26, 2019, 12:26:32 am
content: Quote from: apis on January 24, 2019, 09:25:29 pmNo. I read some recent articles about this. AFAIK there is no longer significant development going on in the area of using algae to make oil. It seems that it is next to impossible to farm algae on an (industrial) scale big enough to produce a reasonable amount of oil at a reasonable cost.

author: apis
author_rank: Super Contributor
timestamp: January 26, 2019, 12:51:23 am
content: It might be too hard to grow wild algae from the oceans, but there is still a lot of research trying to bioengineer different algae to make them easier to grow. So maybe some day in the future.