Sustainable Ammonia and Advanced Symbiotic Fertilizer Production Using Catalytic Multi-Reaction-Zone Reactors with Nonthermal Plasma and Simultaneous Reactive Separation

Abstract

The theoretical bases of a novel intensified catalytic multi-reaction-zone reactor (M-RZR) system are described. The M-RZR with two reaction zones (RZ-1 and RZ-2) was used for ammonia synthesis. In the catalytic nonthermal plasma reaction zone (RZ-1), ammonia was synthesized and it was immediately sequestrated by a highly porous polymeric solid acid absorbent in the ammonia neutralization reaction zone (RZ-2). The solid acid was a sulfonated cross-linked porous polystyrene foam known as polyHIPE polymer (s-PHP, HIPE = high internal phase emulsion). The s-PHP and its neutralized version (sn-PHP) were previously developed as an advanced symbiotic fertilizer (or synthetic root system) for agro-process intensification for the enhancement (50–300%) of crop yield and nitrogen fixation especially under water and nutrient stress. In this first ever “proof-of-concept” study of the M-RZR system, without any attempt for optimization, it was shown that the ammonia conversion per pass reached ca. 40% and ammonia concentration was ca. 20 vol %. The energy cost of ammonia was 0.76 MJ/g NH3 which was 2 times smaller than optimized systems in which the ammonia concentration in the product stream was ca. 1.5 vol %. Direct conversion of hydrogen enhanced clean syngas (a 1CO + a 2CO2 + a 3H2 + a 4N2 + a 5CH4) to ammonia and its reversible sequestration by CO2 to form solid ammonium carbamate/carbonate was demonstrated. This method is not only useful for direct conversion of syngas to ammonium carbonate/urea fertilizers but also for obtaining anhydrous ammonia for fuel applications. The reactive in situ air separation was also demonstrated for the generation of nitrogen for ammonia synthesis and oxygen for the gasification of biomass as a sustainable source of hydrogen.

Plasma-driven catalysis: green ammonia synthesis with intermittent electricity

“…Next to Ru-catalysts, other supported metal catalysts were tested for plasma-catalytic ammonia synthesis (and ammonia decomposition). 131,152,156,157,159,168,276,277,279,280,[287][288][289][290][291][292] In most cases, supported Co, Ni, and Rh catalysts are found to be most active among the tested catalysts. 131,156,159,276,277 Such metals have less ammonia desorption limitations than the classical Fe and Ru catalysts for thermal-catalytic ammonia synthesis.…”

“…224,225 An afterglow normally describes the effluent of a plasma reactor. However, the term is sometimes used more broadly to indicate that ( plasma) species are no longer exposed to The listed plasma reactors are dielectric barrier discharge (DBD), 96,131,142,[143][144][145][146][147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163][164][165][166][167][168][169] (low pressure) glow discharge (GD), 170,171,[172][173][174][175][176][177][178][179]180 microwave plasma (MW), [181][182][183][184][185]…”

“…dielectric properties and morphology), thereby influencing the plasma-phase dissociation of activated molecules. A method to modify the plasma by radicals was proposed by Akay et al, 152,168,260 who used a mix of a dielectric material with a supported transition metal catalyst in the plasma reactor. The dielectric material acts as a plasma catalyst promoter (PCP), which modifies the plasma characteristics, whereas the transition metal catalyst performs the catalytic function.…”

A Review about the Recent Advances in Selected NonThermal Plasma Assisted Solid–Gas Phase Chemical Processes

“…Two interesting studies were also published on multireactor configuration, with the aim of improving the efficiency of the process. Akay [36] studied a catalytic multireaction-zone reactor (M-RZR) system, divided in two main zones (RZ-1 and RZ-2), for ammonia synthesis. The first zone (RZ-1) was used for the catalytic nonthermal plasma ammonia synthesis, which was immediately sequestrated by a highly porous polymeric solid acid absorbent in the neutralization reaction zone (RZ-2).…”

Waste to Chemicals for a Circular Economy

“…The most effective possibility is the development of at echnology for the direct syngast ou rea conversion.T here are very limited studies in this direction. Akay [18] indicated the possibility to use catalytic multi-reaction-zone reactors with nonthermal plasma and simultaneous reactives eparation for direct fertilizer production.A ne xtension of current electrocatalysts for direct ammonia synthesis [19] could allow producing directly urea.…”