Nitrogen fixation with renewable electricity: Plasma catalysis as an alternative for small-scale ammonia synthesis?

Abstract

Ammonia is one of the most produced chemicals, mainly synthesized for fertilizer applications. Renewable ammonia is considered as a zero carbon fuel and hydrogen carriers of the future. However, renewable resources such as wind and solar are fluctuating. This has spurred research interest in alternative technologies for renewable ammonia production methods better suited to fluctuating electricity sources. Plasma catalysis is proposed as an option for electricity-driven ammonia synthesis. Lastly, the outline of the thesis is highlighted.

Incorporation of a Metal Catalyst for the Ammonia Synthesis in a Ferroelectric Packed-Bed Plasma Reactor: Does It Really Matter?

“…For pure thermal catalytic processes, activation energies determined using Arrhenius plots are around 60–115 kJ/mol depending on the promoters used during the process . For the plasma-catalytic synthesis of ammonia, lower values found for different Ru-based catalysts are 20–40 kJ/mol . Claimed interpretation of this lower activation energy is that plasma contributes to excite the nitrogen molecule, favoring its dissociation on the catalyst site.…”

“…As well as activation energy, turn over frequency (TOF) is a typical magnitude utilized to discuss catalytic efficiencies. It has been also used for plasma catalysis processes where values around 10 –3 –10 –2 s –1 have been reported for the ammonia synthesis reaction . A rough calculation of TOF referred to the amount of Ru in the Ru-Al 2 O 3 /PZT pellets rendered values around 4 × 10 –4 s –1 , slightly lower than those obtained in these works.…”

Causality Analysis of the Green Ammonia Synthesis Process Using the Convergent Cross Mapping Algorithm

“…The overall cost of ammonia production is estimated to be 225−315 USD/t NHd 3 for natural gas-based processes and 110−340 USD/t NHd 3 for coal-based processes. 42 Despite the low costs, the required energy and CO 2 emissions of these processes are alarmingly high. The average energy consumption and direct CO 2 emissions are 28 GJ/t NHd 3 (LHV) and 1.57 for t COd 2 /t NHd 3 natural gas-based processes and 48 GJ/t NHd 3 (LHV) and 4.50 t COd 2 /t NHd 3 for coal-based processes, 43 respectively.…”

“…Particularly when renewable energy is sufficient, all of the water electrolytic tanks, air separation units, and ammonia synthesis plants can be powered by green electricity. With the further improvement of green electricity technology and the operation level of the ammonia synthesis process, the cost of green ammonia is expected to be reduced to 310−610 USD/t NHd 3 in 2050, 42 which would significantly accelerate the carbon-neutral strategy proposed by the Chinese government.…”

An anthropocene-framed transdisciplinary dialog at the chemistry-energy nexus

“…Current annual industrial ammonia production is 185 Mt. 57 This represents the amount of anthropogenic elemental nitrogen that enters the reactive nitrogen (Nr) pool every year: 75-80% in the form of fertilizers and 10% as explosives. Fertilizers include urea (NH 2 ) 2 CO, ammonium sulfate (AS), diammonium phosphate (DAP), monoammonium phosphate (MAP), ammonium nitrate (AN), and calcium ammonium nitrate (CAN).…”