[HN Gopher] Reducing Iron Oxide with Ammonia: A Sustainable Path... ___________________________________________________________________ Reducing Iron Oxide with Ammonia: A Sustainable Path to Green Steel Author : PaulHoule Score : 67 points Date : 2023-04-02 18:43 UTC (4 hours ago) (HTM) web link (onlinelibrary.wiley.com) (TXT) w3m dump (onlinelibrary.wiley.com) | Robotbeat wrote: | I don't get this. We already use direct reduction using about | half hydrogen, and that can be increased to over 90%. Producing | ammonia via the Haber process means losing 40% or so of the | energy (and potentially more as you convert it back), so why not | just use hydrogen directly? Simply because moving hydrogen is | harder than ammonia? I think it makes way more sense to just make | and use the hydrogen on-site. | azernik wrote: | This isn't using ammonia to transport hydrogen; the nitrogen is | what's reacting with the iron. | | And yes, ease of transportation and reactivity is a big | motivator. | | From the abstract: | | "Ammonia is an annually 180 million ton traded chemical energy | carrier, with established transcontinental logistics and low | liquefaction costs. It can be synthesized with green hydrogen | and release hydrogen again through the reduction reaction." | | Also: "The authors show that ammonia-based reduction of iron | oxide proceeds through an autocatalytic reaction, is | kinetically as effective as hydrogen-based direct reduction, | yields the same metallization, and can be industrially realized | with existing technologies." | thereisnospork wrote: | >the nitrogen is what's reacting with the iron. | | Only in a supplementary manner to form a nitride coating as | rust proofing - the primary reducing agent is hydrogen, | forming water. | | relevant snippet: | | >>The nitride formation is another key advantage of ADR, as | nitriding improves the aqueous corrosion resistance of | iron.[29] The nitride passivated the otherwise highly active | reduced iron, offering a safety-critical benefit for handling | and logistics. Otherwise, for the downstream processing of | the reduced material, the porous sponge iron is prone to re- | oxidation and strong exothermic reactions with oxygen or | moisture due to its high surface-to-volume ratio (typically | above 40 vol% porosity[4]). Thus, the sponge iron produced by | HyDR must be compacted into hot briquetted iron to reduce the | porosity for shipping and handling, which is not necessary | with ADR. | algo_trader wrote: | > Producing ammonia via the Haber process means losing 40% or | so of the energy | | This seems wrong. I believe that green HB process would be | 80%-90% efficient since the heat is re-used? I have read | conflicting papers. | | Of course, HB is still a capex-heavy process. | | Maybe the 40% number is for fossil methane to ammonia? | twawaaay wrote: | I also think so. Rather than move hydrogen, move the | electricity or the iron. Produce hydrogen on site and even on | demand to get rid of most of the need to store/transport it. | | As to cost, who can quantify me the risks of having and | transporting so much ammonia? | gumby wrote: | You said it: transporting, storing, and otherwise handling | ammonia is easier than H2. Amd handling a lump of coke is even | easier, which is why we started there. | PaulHoule wrote: | i think the question is how far you are shipping the hydrogen. | If, say, people are making hydrogen in (say) the Middle East | and shipping it to (say) Europe then the overhead of liquifying | or compressing H2 is on the same order as converting to | ammonia. In that paper they demonstrate that you can just use | the ammonia directly to reduce iron and not have a separate | system to convert it back. | | If you have a big wind power or solar complex like the ones | being built in the North Sea or Australia you might be better | off using hydrogen directly. | philipkglass wrote: | I would guess that even better than shipping ammonia or | hydrogen to European steel plants would be to build new steel | plants near the hydrogen producers, wherever they may be, and | shipping iron ore there while shipping steel back out. Since | iron ore and steel are much denser than either ammonia or | hydrogen and do not need pressure vessels or chilling they | can be shipped at lower speeds (save transport energy | consumption) and save money too. | conradev wrote: | This is how Iceland exports the bulk of its hydroelectric | energy, but they use aluminum | frankus wrote: | Anhydrous ammonia's volatility is on the order of that of | propane/LPG (although a lot more hazardous to inhale), so | the containment is easier than what the words "pressure | vessel" might evoke. | tonyarkles wrote: | I'm asking this 100% from a place of curiosity because I | don't know the answer. From iron ore to steel, how much | waste is there? If the waste fraction is large, people | might balk at the idea of either leaving that waste behind | in the hydrogen-host country or burning fossil fuels to | ship it around to have a carbon-free extraction process. | to11mtm wrote: | > From iron ore to steel, how much waste is there? | | Depends on how we define 'waste' and at what part of the | process. | | When they start with the rock from the ground/pit, the | rocks/etc are often crushed, running through some sort of | slurry while basically separating the 'ore' out from | silicates/etc that will be around them. I'm guessing this | is already done close to the site, since transport cost | could be fairly high even by past standards. | | What you wind up Iron ores that are considered 'worth' | mining, the actual Iron content is anywhere from ~48% to | ~72%. They'll typically have Oxygen, Possibly also Carbon | or hydrogen as the 'impurities'. | | So, there's still a lot of potential waste in | transporting all of that. | | [0] - Also, that would theoretically be useful in filling | the pit back up, one would hope. But not sure on that | one. | adastra22 wrote: | Anywhere you have water you have hydrogen. | to11mtm wrote: | Interestingly, the paper mentions that the reactions do | produce (some) hydrogen, which could perhaps be | recaptured. | | However, a bigger concern upon a glance is that this | process does produce NOx emissions... | londons_explore wrote: | NOx from big industrial processes tends not to be an | issue. Catalytically reducing it to N2 and O2 is easy, | and at the same time, you get out 'free' high grade heat, | which there is usually some use for elsewhere in the | plant. | ClumsyPilot wrote: | Exactly, I struggle to see any situation, barring | mismanagement or disaster, where you should be shipping | tankers full of hydrogen byproducts like ammonia and losing | most of the energy in the process. | | We are currently importing all the natural gas in Europe, | and both the price and carbon footrpint are more than | double of what pipeline delivered from Russia. | | You could build a pipeline from the middle east to Europe | for hydrogen. We are already building powerplants in Sahara | to export energy to EU. But I do not see why you should | ever need to. | | Iron ore and Aluminium ore is literally everywhere. We | could move all of primary metal refining close to equator | for solar power. China is close enough to equator, and | produces huge quantities of Iron. Australia could be | producing iron, they have plenty of sun. | | Or Europe could produce hydrogen in the summer and store | for the winter to keep refineries running. | rainbowzootsuit wrote: | Hydrogen, being so small, penetrates directly through the | molecular structure of steel and in the process causes | embrittlement of the steel. Is a long distance H2 | pipeline a solved problem using alternate materials? | KMag wrote: | But the mass of the extracted oxygen exceeds the mass of | the ammonia used, and we're only talking about 250 PSI to | liquify anhydrous ammonia at room temperature. A large | pressure vessel's mass is going to be negligible compared | to the mass of the ammonia it holds. So, the same | displacement ship traveling at the same speed can supply | the production of more steel if you ship the ammonia to the | iron ore instead of the other way around. | photochemsyn wrote: | I think it's more rational to ship the hydrogen as methane, | rather than ammonia. The energetics are comparable IIRC | (Sabatier for methane, Haber-Bosch for ammonia, but it's more | or less the same kind of high-pressure moderate-temp | chemistry pipeline). Methane from CO2 + H2 vs. ammonia from | N2 + H2, it's just that the latter technology has seen more | research and investment. | canadianfella wrote: | [dead] | boshomi wrote: | Reduction of iron ore with carbon monoxid in closed loop: | | * Decarbonisation of BF-BOF through thermochemical closed carbon | looping. | | * Demonstration of mass and energy flows of thermochemical BF-BOF | system. | | * 88% emissions reduction of UK steel industry through PS720 | million investment. | | * Decarbonisation without retiring of existing BF-BOF, reducing | stranded assets. | | * After 5 years, PS1.28 billion savings and total UK-wide | emissions reduction of 2.9%. | | "if the thermochemical closed reactors were exclusively powered | by electricity, it would require 607 kWh/t liquid steel." | | >>Cost effective decarbonisation of blast furnace - basic oxygen | furnace steel production through thermochemical sector coupling<< | -- https://doi.org/10.1016/j.jclepro.2023.135963 | sacrosancty wrote: | [dead] | TEP_KimIlSung wrote: | [dead] | eutectic wrote: | What about electrolysis? ___________________________________________________________________ (page generated 2023-04-02 23:00 UTC)