Portable ammonia factories could fuel clean cars
FORGET hydrogen: ammonia could be the answer to developing an emissions-free fuel for cars.
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.
In their system, a piston rapidly compresses hydrogen and nitrogen, heating the gases to 400 °C. The mixture is fed into a chamber containing an iron oxide catalyst, which sparks a reaction that further heats the gases and generates ammonia. In a third chamber, the mixture decompresses and cools down to room temperature. As it does so, it pushes against another piston, from which mechanical energy is recovered and fed back to the compressor, significantly cutting the process's power consumption.
Vehicle fuel-cell technology releases hydrogen on demand
Prof Travis Williams and colleagues from the University of Southern California (USC) devised a way to efficiently catalyse the release of hydrogen from ammonia borane.
Hydrogen fuel cells are now a relatively mature technology; however, as a gas, hydrogen can generally only be stored in high-pressure or cryogenic tanks. As Williams noted, in the case of a vehicle with a tank full of hydrogen, this could be a problem in the event of a collision.
Because of this, several groups have taken an interest in trying to use ammonia borane — a nitrogen-boron complex that can be stored as a stable solid — as a fuel.
However, until now it has proved difficult to efficiently produce enough hydrogen from boron compounds to make them viable for use in conjunction with fuel cells.
The team has developed a catalyst system that releases enough hydrogen from its storage in ammonia borane to make it usable as a fuel source. Moreover, the system is air stable and reusable, unlike other systems for hydrogen storage on boron and metal hydrides.
In addition, they have developed a catalyst system that releases enough hydrogen from its storage in ammonia borane to make it usable as a fuel source. What's even more exciting is the system is stable in air and reusable. R&D Advances in Hydrogen Fuel Storage Technology Promise Green Benefitsall 3 news articles »
msnbc.comProf Travis Williams and colleagues from the University of Southern California (USC) devised a way to efficiently catalyse the release of hydrogen from ammonia borane. Hydrogen fuel cells are now a relatively mature technology; however, as a gas, Breakthrough in Hydrogen Fuel CellsHydrogen fuel gaining respectHydrogen storage breakthrough and $4.1m investment for fuel cell industryall 11 news articles »
