A chemical loop utilises a recyclable metal with water and hydrocarbon feedstocks to produce hydrogen, water and carbon dioxide. The metal is involved in a repeating cycle of reaction steps
Technology
What is it?
A chemical loop utilises a recyclable metal with water and hydrocarbon feedstocks to produce hydrogen, water and carbon dioxide. The metal is involved in a repeating cycle of reaction steps.
Why is it important?
Hydrogen and carbon dioxide are obtained as separate high-purity gas streams, allowing easier integration of CCUS.
Characteristics
- Inputs: Hydrocarbons / coal / tar. Optional: biomass
- By-products: CO2, other hydrocarbons
- Operating temperature: 700 to 1000°C
Benefits
- Multiple feedstock options: fuel gas (including alcohol, hydrocarbons [when combined with reforming], biogas, waste gas), heavy bio-crude, biomass, tar and coal
- Solid oxygen carrier eliminates need for air as oxygen supply – fuel is converted into a pure stream of CO2 and H2O, which is easily separated
- High purity hydrogen (99.95-99.999%) can be obtained as a separate gas stream
- High fuel conversion efficiency
- Heat from exothermic oxidation can be channelled to the exothermic reduction to reduce required heat input
- If using fluidised bed reactor: continuous operation, supply of pure separated CO2, N2 and H2 - potentially a poly-generation application
- Can be incorporated with syngas conversion processes
- Carbon capture integration has been shown to be effective
Limitations
- Oxygen carriers require replacement over time – utilisation of low-cost natural minerals is important to reduce the cost
RD&D priorities
- Optimise the composition or structure of the oxygen carrier to improve stability
- Evaluate fuel flexibility and investigate natural minerals as oxygen carriers to improve overall dynamic process characteristics
- Improve reactor design
- Improve process development and integration
- Improve process simulation
- Demonstrate prototypes and pilot plants (large scale, long term operation)
- Demonstrate use of oxygen carriers in industrial environment
Known active organisations
- The Australian National University
- CSIRO
- Monash University
- The University of Adelaide
- The University of Newcastle
- The University of Queensland