Despite reducing costs associated with the production of green hydrogen, the production of blue hydrogen remains cheaper and is frequently considered as a transitional hydrogen production option as part of establishing a hydrogen economy. Blue hydrogen production is conventionally executed via steam methane reforming (SMR) coupled with CO2 sequestration. SMR is however an endothermic reaction, hence it requires supplementary heat provision and consequently produces two substantial sources of CO2 (one at comparatively low concentrations and pressures) which collectively results in poor overall sequestration efficiency. An alternative to SMR is the use of autothermal reforming (ATR), this effectively involves the co-injection of oxygen and steam as reactants, eliminating the requirement for supplementary reactor heating ). A single comparatively high concentration and pressure CO2 production stream results which is imminently more suitable for sequestration. The reason ATR is not currently widely used for hydrogen production is (partially) the cost of producing the require oxygen via air separation or the parasitic nitrogen load if air injection is used instead of oxygen (this is considered in the provision of hydrogen for ammonia production for example).
In the current project we will first establish a base case scenario in which hydrogen is generated with an electrolyzer and is co-located with a combined cycle power plant (CCPP) running off natural gas and which acts in a firming capacity – oxygen is emitted in this case. This arrangement will be tested against different levels of renewable energy availability (from 25 % to 100% which roughly reflects different Australian regions) – cost (LCOH) and overall carbon intensity being key assessment variables. Opportunities to use the oxygen by-product as part of optimising power generation will then be considered. With this as a starting point the roadmap for transition to fully green hydrogen production via this comparatively simple combined route will be articulated.
Following this and using the above base case scenario as a reference we will proceed to assesses the viability of combined production of green and blue hydrogen with the oxygen ‘by-product’ of green hydrogen production via water electrolysis being used in this case as the required feed to an ATR process in the first instance optimised for hydrogen production. We will then progress to consider its use for coal gasification. Assessment in both cases will again be against economics (LCOH) and carbon intensity but will also consider the practical hurdles and opportunities of integrating these two hydrogen production processes.
Partners: INPEX Holdings Australia Pty Ltd, Victorian Government Department of Jobs, Precincts and Regions, The University of Western Australia
Project Researchers: Professor Michael Johns, Dr Keelan O’Neill, Dr Saif Al Ghafri
Duration: 12 months