Tri‐fold process integration leveraging high‐ and low‐temperature plasmas: From biomass to fertilizers with local energy and for local use
Résumé
In the present study, a series of thermochemical equilibrium modeling was conducted to assess the thermodynamic potential of biomass conversion to ammonia using thermal and nonthermal plasma at small- and large-scale production. The system was designed and evaluated for five different locations in Australia including the Northern Territory, South Australia, Western Australia, and New South Wales using local biomass feedstock. The equilibrium modeling showed that the pathway of biomass to biomethane using an anaerobic digestion reactor, biomethane to hydrogen using a thermal plasma reactor, followed by conversion of hydrogen to ammonia via a nonthermal plasma reactor is a plausible route, by which the exergy efficiency of the process can be as high as ~60%. It is identified that the thermal plasma reactor required two distinct zones at 3000°C < T < 4000°C and 1500°C < T < 2500°C. The first zone aims at converting electric energy into very high temperature thermal flow while the second one enables to split methane molecules into solid carbon and hydrogen. The new ammonia process is also assessed from the viewpoint of the current industrial transformation, being accelerated by the post-COVID economy, which moves toward local, resilient, integrated and self-sufficient production under the umbrella of an emerging fractal economy. With respect to local production, the developed process is designed for a quick response to farm use and on-time production in view of the demands of modern ICT-sensor based precision agriculture. The proposed process was found to be flexible (“resilient”) against production scale, geographical location, price and type of feedstock, and source of renewable energy. The system was found to be flexible against different feedstock such as spent grape marc, mustard seed, bagasse, piggery and poultry. The system can be self-sustained up to ~80% at T = 3500°C; with the thermal plasma reactor-zone 2 producing the electricity requirements for the nonthermal plasma via a steam turbine power block. Finally, the system it is investigated to which degree the system is adaptable to local production, self-sufficient, and circulatory.