• eleitl@lemmy.world
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    1 year ago

    Haber-Bosch for fertilizer, Fischer-Tropsch for synfuel.

    But, really, we need something with mild conditions and preferably something directly electrosynthesis driven. Large potential for improvement in both.

      • eleitl@lemmy.world
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        1 year ago

        The Haber-Bosch approach to breaking the nitrogen triple bond takes a lot of energy in terms of high pressure and temperature which is not present in the product, hence wasted. Ammonia is a fertilizer either as gas or as ammonium nitrate, and too precious to burn.

        Another random fact: half of the combustion enthalpy present in liquid hydrogen has been spent on its liquification.

        • skillissuer@lemmy.world
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          1 year ago

          And also, you don’t need to use Fisher-Tropsch process either. Methanol is good enough fuel that you can get more directly from syngas and getting fractions of hydrocarbons this way is simply wasteful (tar formation, too light products etc). Additional benefit is easier conversion back to hydrogen if need be

          That is, unless energy density is critical. I don’t think that difference matters in most of the cases

        • skillissuer@lemmy.world
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          1 year ago

          No. Haber-Bosch process is very mature by now and it doesn’t take much more energy than thermodynamically necessary to do so. You get there by recycling heat and reusing energy of compressed gases. The actual problem is getting that hydrogen in the first place

          If you want to use hydrogen as a fuel anyway, you can add that little overhead and get fuel that you can either burn in ICE or go the whole nine yards, crack it back into elements and put that in fuel cells, and, more importantly, this comes with massive advantage of ammonia being about as easy to liquefy as propane, and we already have propane fuelled cars. Energy density is vastly higher than hydrogen this way, less than propane, sure, but it’s something

          Another option is dimethyl ether, but this thing needs to take carbon from somewhere, just like methanol