P2C

General goal

The aim of this project is to demonstrate CO₂-neutral olefin and ammonia production by renewable electricity-driven processes via a novel power-to-heat, electrocatalytic and plasma-based routes. For each trajectory 5 scientific objectives have been defined.

For "Electrified olefin production"

1. Objective 1. Synthesis and screening of 3D printable ceramic materials (SiC, ZrO2, Al2O3) as steam cracking reactor Advanced ceramic materials for steam cracking because they offer the promise of attaining high selectivity to ethylene at high conversion levels while minimizing coking and carburization. Essential is the assessment of the oxidation, carburization, coking tendency, failure and flexure strength change in a high temperature steam environment.
2. Objective 2. Improve the olefin selectivity of steam cracker furnace by electrification Optimization of the heat flux profile for maximum olefin selectivity. The objective is hereby to minimize the pressure drop, implement smart 3D profiles, and so come to a novel and more compact design.
3. Objective 3. Prototyping an electrified steam cracker The objective is to intensify the steam cracking process by using power to heat instead of using burners. A ceramic prototype will be developed and compared to an electric resistance–heated reactor using a classical high temperature alloy. Alternative heating techniques that will be studied are: inductive, resistive, convective heat transfer and microwave heating.
4. Objective 4. Design, optimize and scale-up of a catalytic plasma reactor The performance in terms of energy specific ethylene productivity (ethylene productivity/energy consumption) for a single discharge will be studied. In a later stage, scale up the catalytic plasma reactor by numbering up the number of discharges between the two electrodes and increasing flow rate and power accordingly.
5. Objective 5. computer modelling of the plasma chemistry in the plasma reactor of Objective 4 A computer model of the plasma chemistry in NPD plasma will be developed that can guide the experiments in Objective 4. This model will allow to further optimize the initial design "in silico".

For "Ammonia production"

1. Objective 6. To reveal the mechanism of N₂ activation in candidate electrocatalysts. The first step of the nitrogen reduction reaction (NRR), N₂ activation that relies on the choice of electron donor-acceptor pairs, will be studied by means of density functional theory (DFT) calculations and mechanistic study of known transition metal compounds.
2. Objective 7. To screen and rationally develop highly efficient electrocatalysts for NRR. Catalysts with the theoretically electron donor-acceptor pairs will be prepared, tested and further optimized to achieve efficient NRR. The aim is to develop low-cost and environmental-friendly electrocatalysts with a Faradaic efficiency over 50% at a current density of at least 10 mA/cm2 .
3. Objective 8. Investigation and optimization of extrinsic parameters for durable NRR performance. Mass transport limitations will be studied via electrocatalyst integration in tailor-made gas diffusion electrodes. The influence of process parameters will be investigated and optimized, aiming at electrode stability for continuous and stable NH₃ production.
4. Objective 9. Investigation and development of plasma reactors for NH3 production. Three different plasma setups will be investigated for NH3 production, i.e., dielectric barrier discharge (DBD) and gliding arc (GA), as well as a plasma jet interacting with liquid H₂O. The first two setups will also be tested with the electrocatalysts. The experiments will be supported by modeling, and conditions with maximum NH₃ yield and minimum energy cost will be explored. The target is to achieve an NH₃ yield above 5% and energy cost around 1.5 MJ/mol.
5. Objective 10. Develop stand-alone electro- and plasma reactor driven by a photovoltaic solar cell. Integration of both reactor concepts (based on electrocatalytic and plasma (catalytic) ammonia production) to a stand-alone device powered with sunlight and usage of atmospheric air as feedstock. In a so-called ammonia panel concept, the electrolyser and plasma gas-flow reactors will be integrated with a photovoltaic solar cell. The N₂ and H₂O in air are used as reactant for ammonia production. The aim for this prototype is to realize an ammonia production rate of 6.2 mol h-1 m-2.