Portable Ammonia Factories Could Fuel Clean Cars

by Helen Knight (New Scientist) Ammonia produces just nitrogen and water vapour when burned and, unlike hydrogen, it is relatively easy to store in liquid form. That means transporting ammonia will not require costly new infrastructure, says John Fleming of SilverEagles Energy in Lubbock, Texas.

Fleming and Tim Maxwell at Texas Tech University, also in Lubbock, are developing a system to produce ammonia that can be installed in filling stations. Powered by mains electricity, it first produces hydrogen from water using electrolysis, then combines it with nitrogen from the air to produce ammonia.

To achieve this, the researchers have adapted the Haber-Bosch process used to make ammonia industrially. Their version works on a small scale and can make ammonia fairly cheaply.

...Edman Tsang, a chemist at the University of Oxford, says that a mobile unit that can turn water and electricity from renewable energy sources into fuel ammonia would be useful in remote areas. Fleming and Maxwell are already working with the US army and air force, who have each expressed interest in using the technology on the battlefield.

However, Tsang is not convinced that the hydrogen needed to make ammonia can be produced economically using electrolysis.

...Conventional cars can already make use of ammonia - they can run on a mixture that is 90 per cent gasoline and 10 per cent ammonia, says Fleming. So-called flexible-fuel vehicles, which use a mixture of gasoline and ethanol, could also be modified to run on a fuel that is up to 85 per cent ammonia. Such vehicles have sensors that constantly detect the exact proportion of gasoline and ethanol being fed through, and adjust their fuel injection and spark timing accordingly. To run on ammonia, the vehicles would need to be reprogrammed and equipped with a fuel tank capable of storing ammonia under pressure. READ MORE