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New Process Promises Ammonia From Air, Water, and Sunlight
The synthesis of ammonia is one of the globe's most significant industrial applications of chemistry. PhysOrg reports the publication in the August issue of Science (sadly, article is paywalled) the description of a low-energy process to syntheize ammonia for fertilizer using just air, water, and sunlight, by zapping with electricity water bubbling through a matrix of iron oxide, and sodium and potassium hyroxide. Electricity isn't free, though — "Low energy" in this case means two-thirds the energy cost of the long-in-use Haber-Bosch process. Researcher Stuart Licht is getting some of the energy to run this reaction from a high-efficiency solar cell he's created, which creates hydrogen as a byproduct.
Along with the elimination of the need to produce hydrogen from natural gas, the overall emissions are reduced quite significantly. The whole process also takes place at milder conditions, not requiring 450C and 200 times atmospheric pressure as the Haber-Bosch process does. ... But even with Licht's method, [University of Bristol electrochemistry professor David] Fermin points out that we are far away from being able to replicate nature's efficiency at converting nitrogen from the air to useful chemicals, which is done by nitrogen-fixing bacteria. "What is truly remarkable is that nature does it incredibly efficiently at low-temperature," Fermin added.
And yet, if something more efficient can replace the Haber-Bosch process, it would lower the energy input of the production of one of the worlds most important chemicals and lead to a notable reduction in global CO2 emissions.
But without mining the core out of an asteroid, where will we build our secret space lairs?
Won't somebody think of the mad scientists?
I don't suffer from insanity, I enjoy every minute of it!
How about we reuse all the fixed nitrogen we already made instead? Right now water in Toledo, Ohio is undrinkable because of algae blooms in Lake Eerie. I'm sure we use a lot of energy in the Haber process, but I think that's a trivial concern compared to the environmental problems we can cause if we keep pumping organic nitrogen into the environment. It could turn out to be a very very bad thing to do overall. I think we'd be way better off if we reduced ammonia production, rather than switching to a more efficient way to make ammonia. I'm all for innovation generally, but to me, this idea reeks.
You can help. Off yourself. Now git.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
Something not mentioned here is that ammonia is suitable as a fuel in internal combustion engines. Ammonia is liquid under modest pressures (like propane), is easily transported, and will burn inside an engine.
If we made ammonia out of nitrogen and water vapor, then it would become nitrogen and water vapor again when burned. It's a closed cycle that would not alter the composition of the atmosphere at all.
It probably wouldn't be suitable as a fuel for your car, because of safety issues (if you hammered a hole in the fuel tank, the fuel inside would flash boil and could shoot out into your eyes causing a chemical burn). However it would probably be fine for trains, airplanes, ships, and so on, where special handling procedures could be enforced and people could be required to wear goggles before working on the fuel tank.
Here's some background on the Bosch Haber process.
Whether a reaction will occur is based on whether energy is required and whether the reaction increases entropy. In the case of nitrogen+hydrogen => ammonia, the reaction is both exothermic and increases entropy at room temperature and pressure. If one could somehow ignite the process it would be self-sustaining.
The problem is, to ignite the reaction you first need to break N2 molecules into individual N atoms, and this requires a great deal of initial energy which is regained in subsequent steps. Something like 7eV per molecule to break them apart. The molecules in normal air have a bell-curve spread of energies, but very few of them reach energies this high: the reaction happens at room temperature, but very *very* slowly. A handful of molecules per second will react.
To get around this you can raise the temperature, increasing the probability that molecules will have enough energy to break apart. The entropy produced is inversely proportional to temperature, so when you start to have N2 molecules with enough energy to break apart, the reaction is no longer favored because it would result in an entropy decrease.
Since 4 moles of reactants result in 1 mole of product, increasing the pressure of the reactants will tend to favor the products, so you can use this to offset the deficit in entropy.
The Bosch-Haber process tries to find a "sweet spot" by increasing the temperature to get a reasonable number of N2 molecules to break apart, and high pressure to make the process favor the products.
At 200 ATM and 400 degrees, the yield is 15% (!).
Reaction vessels for this pressure and temperature are expensive, and the process requires multiple cycles of compression, decompression, removal of ammonia, and recompression. This takes a *lot* of energy and uses *very* expensive compressors which wear out over time and have to be replaced.
I haven't read the paywalled article yet, but if I'm understanding the abstract, they are breaking apart the nitrogen electrochemically. Just as running a current through molten NaCl will break it into atomic sodium and chlorine, running a current through nitrogen dissolved in KOH and NaOH breaks it apart and the reaction then proceeds at normal conditions. The reaction also supplies its own hydrogen by breaking apart water.
Much of the "green revolution" is due to the use of nitrate fertilizers, and the source material is finite: guano from Peru, for example.
If this process is as efficient as the abstract suggests and can be industrialized, it would be *huge*. It would give us an essentially infinite source of nitrogen-based fertilizer and reduce the worldwide consumption of energy by a couple of percent.
Coupled with a source of renewable energy, it would mean that the world could sustain its food production at current levels indefinitely.
This could be really, *really* big news.
with the Haber process needing 450C temperatures and and 200 ATM pressure, I think your teacher was over-reacting. Anyone with the facilities to do that didn't need your teacher to help them
Oh, please. Creating explosives is easy (well, the creating part is easy. The "don't blow yourself up prematurely"-part usually not so much).
You merely need nitrating acid which you get by mixing nitric acid and sulfuric acid. Both acids are relatively easy to obtain (Both acids are sold on Amazon over here). Then you mix the nitrating acid with cotton, dry the stuff carefully and you got: Gunpowder Cotton, also called: Smokeless Gunpowder. All you need is a fumehood because mixing the acids is a bit hard on the lungs.
If you want to up the ante: Use glycerin (a laxative, also easily obtainable) instead of cotton. And, you guessed it: You get Nitroglycerin. However, the nitration process is exothermix and you need to be very careful when mixing the acid into the glycerin or it will blow up.
Those are just two examples. Almost the same process is used to produce TNT, by the way.
billions of useless mouths
If you want to reduce the population, feel free to start by offing yourself, Adolf.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Before I get slammed by a P-Chem major, here's what's really going on with the entropy.
The reaction is exothermic, and this release of heat increases the entropy of the universe. At the same time, 4 atoms of source become 1 atom of product, so this aspect of the reaction *decreases* the entropy of the universe. (There's more ways that 4 atoms can be arranged in a box than there is to arrange 1 atom.)
At room temperature, the entropy increase from the release of heat is greater than the entropy decrease from the reduction in states, so the reaction is favored.
The entropy from the release of heat is inversely proportional to temperature. Double the [absolute] temperature and you halve the increase in entropy from the release of heat. With higher temperatures, the entropy increase from "release of heat" is smaller than the entropy decrease from "change of states", the total change of entropy is negative, and the reaction is no longer favored.
I wrote a simpler/shorter explanation to avoid losing sight of the main point.
It's Science. Accessible through any respectable library.
http://e360.yale.edu/feature/u...
http://www.rsc.org/chemistrywo...
http://phys.org/news/2013-10-a...
Rgds
Damon
http://m.earth.org.uk/
There's some free space on the dark side of the moon, but you wouldn't like the neighbors.
When I hear about clever-but low energy processes that have low yield because -- and only because -- the scientists feel the need toss a stock photo of a windmill or solar cell into the paper to trigger that warm fuzzy feeling, I think to myself, "How cute."
Decades of cuteness now. It's not cute any more.
The world needs less cuteness and more large scale thinking. Gigawatts not milliwatts. We also need to get into reverse osmosis in a big way, so we can start to manufacture fresh water from salt and pipe it inland. This requires massive amounts of energy.
Real Humans do not need to wait for rain, real humans need not wait for oil and gas to diminish in order to achieve the next step. Real humans better wake up and resume the industrial revolution. We are smart enough to keep it clean.
Follow us down the rabbit hole...
<blink>down the rabbit hole</blink>
WHAT 'S WRONG WITH PINK FLOYD!?
Oh, you mean the Nazi's...
"Kill 'em all and let Root sort 'em out"
Teach a man to steal and you keep him in explosives for a day. Teach a man to synthesize TNT and you can bother the FBI for years.
Pretty sure we've got the last part covered in this thread quite aptly.
You do so as well. BUt with your own urea and a light amount of electrolysis, you can produce your own hydrogen. Rotting bread dough produces tremendous amounts of hydrogen as well. I think hydrogen is being actively suppressed, along with diesel passenger cars.
Chlorate based explosives are easier to make than nitrate based ones. All you need is a bag of road salt, electricity, and a pot of hot water at 60C, and some carbon anodes that don't get chewed by the chlorine gas. I think matches are made from chlorates, but you have to shave a lot of match heads down to get any kind of punch. I remember when I was a kid we used to have fun making exploding noises from match heads. All you need is two male screw bolts and a female nut, about 3/8-1/2". You dp (double penetrate) the female nut from both sides with the two male bolts, and have match shavings between them. I mean you only screw one of them in halfway, shave the matches like into a cup, then screw the other one on very very tight, then loosen like a 10th of a turn, or don't even need to loosen it. Now you take a piece of plastic bag, or even a rag, and tie it to one of the bolt head ends, to make it into a tail, to create aerodynamic drag. with a piece of wire. About a 4 inch or 6 inch tail should suffice on a 1/2 inch set of bolts, that are like 12 inch total length when assembled. Pick it up by the tail, and swing it real high up in the air, so that when it comes down, it comes lined up nicely with the bare bolt aiming directly toward the cement or even asphalt sidewalk, and the plastic bag aerodynamic drag tail end pointing up. When it hits the ground, the contents explode from the sudden shock, and make a really nice, loud noise. Then you can go pick it up, unscrew it, reload, and do it again, but it does eat a lot of matches, like 3 shots out of a small matchbox of 50 matches. We also used to have fun with carbide, (calcium carbide) we stole from the welding acetylene generators from the nearby construction sites. You'd drop a small piece into a wine or beer bottle that the drunkard construction people would leave laying around empty, filled 3/4 with water, then cork it (back in the day they had corks), and wait til it goes pop, and shoots the cork up real high in the air. Then find the cork again, and re-cork it, and repeat. Not as fun as the double screwed match explosion, but it's cheaper when you're so broke, that you can't afford to buy matches under a communist regime, but the calcium carbide is free, you find in for free in the acetylene generators at the construction site. Of course you gotta go when the security guard is gone drinking his sane mind away at the nearby pub, and when he comes back all drunk, he can't run straight to catch you. We all knew the most important trick when running from the security guard if you accidentally bump into him while playing hide and seek, is to run, and when running, take sudden sharp turns, and being a 7 year old kid and him like a 50 year old, running in huge safety rubber boots compared to your tennis shoes, he has a lot of inertia and keeps running straight, and you can escape like that. But one time one of them conspired with a regular on the street person, who was walking her girls, and grabbed me, for him, and I couldn't run away, so I had to take him home, and my mother, to appease his anger, gave him some brandy shots. And all was good, and he wasn't angry at me from than on when he saw me from the distance, because he remembered the free alcohol, but he was still orchestrating ways in his mind to catch me again and get some more alcohol, and I, and my buddies, we had to be careful not to get caught. But we had creative ways to have fun and kill time after coming home from standing in line for bread for like a whole friggin hour, til the bread truck arrived. When you're a 7 year old, and there is a moblike crowd that starts stirring when the line breaks down (kind of like a crowder concert, where people are really excited and try to get close to the stage) sometimes you get lifted from two sides and your feet don't touch the ground, and get carried like that til you land on your feet again, and people acted like that because sometimes the ones at the end would be told that that's it, come back later, we're out of bread. So anyway, we also used to steal half inch