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Comment by lambdasquirrel | Hacker News Reader

I think the real meat of the article is further down, where they discuss replacing the Haber-Bosch process. That's what the article really ought to be about. Haber-Bosch is a huge emitter of CO2, and our industrial agriculture depends on it. That they intend to replace methane with ammonia would be nice, but regardless of that, if this Tsubame process can be made to work, it will have applications beyond that.

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They also talk about ammonia replacing methane in power plants, which is problematic.

It’s very difficult to combust ammonia without producing a lot of NOx. That means more smog, acid rain, asthma and other respiratory disorders.

We’ve gone to huge efforts to reduce and eliminate NOx emissions from vehicles and power plants, so it would be a major setback to start adding new sources of it.

Wouldn’t industrial processes that use H2 directly generally be preferable to having ammonia as an intermediary?

NOx are industrially useful and profitable to scrub out at large scale (and relatively easy too, just pass exhaust gasses through water) because it generates nitric acid, which is an extremely useful and relatively expensive chemical that is the basis for vast amounts of industrial processes. So the use of ammonia in power plants is relatively unproblematic, in fact I would not be surprised if tuning ammonia based power plants to produce the most amount of NOx possible was the most economic choice.

As a bonus, nitric acid can be directly used to create fertilizers, which is one of the central usages of the Haber–Bosch process.

Not sure, whether there's a technically proven ammonia fuel cell yet. For some applications it could enable the use ammonia to generate electricity _without_ NOx emissions.

There is. It is practical to operate at a scale as small as a single wind turbine, for local fuel and fertilizer on a farm.

Where and how do you recommend learning more about this? Thanks.

You minimize NOx production just by running a little bit rich.

NOx output from natural gas plants is today kept down by injecting ammonia.

Haber-Bosch itself does not emit CO2. I presume you mean that the generation of H2 needed for Haber-Bosch is what emits the CO2 - unless using green hydrogen?

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