Technology
What is it?
Electrochemical ammonia synthesis describes a group of methods that can make use of either a hydrogen gas or water feedstock to produce ammonia with nitrogen.
Why is it important?
Electrochemical ammonia synthesis presents a long-term opportunity to create ammonia for export directly if water and nitrogen are used as the feedstocks, skipping the hydrogen feedstock production step which is currently required. This could facilitate reductions in operating costs and balance of plant compared to the traditional Haber-Bosch process.
Characteristics
- Volumetric hydrogen density: High (10.7kg H2 / m3 at 10 bar and 25°C)
- Gravimetric hydrogen density: High (17.8% by mass)
- Storage conditions: Liquid at ambient temperature, 10-11 bar pressure
Benefits
- Synthesis of ammonia directly from water (instead of hydrogen gas) is possible
- Operates at milder conditions than traditional Haber-Bosch synthesis (temperatures below 100°C possible)
- Could potentially make use of waste water, sea water, or alcohol inputs
- Lower operating costs and balance of plant than traditional Haber-Bosch process
- Could theoretically yield energy savings from bypassing the hydrogen production step
Limitations
- Low temperature kinetics
- Energy intensive hydrogen generation
RD&D priorities
- Improve cost competitive ammonia production rate (highest achieved so far is two orders of magnitude lower than required) and conversion efficiency
- Improve high ratio of ammonia to hydrogen generation
- Optimise reactor materials and reaction conditions
Known active organisations
- CSIRO
- Monash University
- Queensland University of Technology
- The University of Adelaide
- The University of Technology Sydney