I have seen this story in several outlets, but haven't heard about NOx emissions from this process. Could someone more knowledgeable shine a light on this?
This version of the story mentions that NOx and particulates are something they will have to work on: https://www.deingenieur.nl/artikel/first-system-to-use-iron-...
At high temperatures.
Burning coal is clean in this sense, as I understand.
But higher temperatures seem to be much more dangerous. I've heard that from critiques of hydrogen burning, they said burning pure hydrogen is unacceptable due to high temperature leading to NOx emission.
Found this:
> It is believed that an increase in the maximum temperature in the combustion zone above 1850 K leads to unacceptably high NOx emissions , and one of the main ways to reduce emissions by the thermal mechanism is to prevent the formation of hot spots in the flame front.
https://translate.google.com/translate?hl=&sl=ru&tl=en&u=htt...
You can store the oxygen released when you produce iron from powdered rust, and use it to burn the iron later.