2 replies to this topic

[mariner]

Despite big marine diesels being about the most fuel efficient IC engines outside of F1 there is still a lot of pressure to cut shipping emissions down. This project in Denmark is looking as ammonia as diesel fuel which is  a new one to me .

 

https://www.bbc.co.u...siness-54511743

[Greg Locock]

The article gently skates over the issue of how you make ammonia to burn in the first place. It's a bit like the hydrogen economy story that greeny pollies love. At the moment we make ammonia by burning oil(sorry can't remember what, is it the haber process?)

 

here we go

 

This conversion is typically conducted at pressures above 10 MPa (100 bar; 1,450 psi) and between 400 and 500 °C (752 and 932 °F), as the gases (nitrogen and hydrogen) are passed over four beds of catalyst, with cooling between each pass for maintaining a reasonable equilibrium constant. On each pass only about 15% conversion occurs, but any unreacted gases are recycled, and eventually an overall conversion of 97% is achieved.^[3]

The steam reforming, shift conversion, carbon dioxide removal, and methanation steps each operate at pressures of about 2.5–3.5 MPa (25–35 bar; 360–510 psi), and the ammonia synthesis loop operates at pressures ranging from 6 to 18 MPa (60 to 180 bar; 870 to 2,610 psi), depending upon which proprietary process is used.^[3]

Sources of hydrogen[edit]

The major source of hydrogen is methane from natural gas. The conversion, steam reforming, is conducted with steam in a high-temperature and -pressure tube inside a reformer with a nickel catalyst, separating the carbon and hydrogen atoms in the natural gas. Other fossil fuel sources include coal, heavy fuel oil and naphtha, while hydrogen is also produced from biomass and from electrolysis of water.

[Canuck]

Soon enough the argument won't be about energy consumption, it will be about consuming energy appropriately (IE the way we've decided). Burning oil to make ammonia (to be burned) to reduce emissions will most certainly be cast as the latter. Sort of how we completely ignore the largely hydrocarbon-based inputs required for the creation and support of electric...well, everything.