Abstract In the present article, the thermodynamic potential of a sustainable plasma-assisted nitrogen fixation process for co-production of ammonia and hydrogen is investigated. The developed process takes advantage of chemical looping system by using a liquid metal such as gallium to drive nitrogen fixation reaction using three reactors including reactor R1 to produce gallium nitride from gallium and nitrogen, reactor R2 to produce ammonia and hydrogen from gallium nitride, and plasma reactor R3 to convert gallium oxide to pure gallium. The results of the thermodynamic assessments showed that the proposed reactions are spontaneous and feasible to occur in the reactors. Likewise, the first two reactions are exothermic with Δ H = - 230 k J m o l and Δ H = - 239 k J m o l in the reactors R1 and R2, respectively with an equilibrium chemical conversion of 100%. The plasma reactor requires thermal energy to drive an endothermic reaction of gallium oxide dissociation with Δ H = + 870 k J m o l . Thermochemical equilibrium analysis showed that the molar ratio of steam to GaN, as well as the operating pressure and temperature of reactor R2 are the main operating parameters identifying the product composition in the reactor such that by increasing the temperature, the molar ratio of hydrogen to ammonia increases. However, by increasing the molar ratio of steam/GaN (φ value) from 0.1 to 1, the hydrogen content of the reactor increases from 45% to 70% at 400 °C. For φ > 1.0, the hydrogen content decreases while more hydrogen participate in the formation of NH3 thereby increasing the mole fraction of ammonia in the reactor. The equilibrium chemical conversion of all three reactors is expected to reach the completion point (χ = 100%) due to the highly negative Gibbs free energy of the liquid metal-based reactions together with a large thermal driving force supported by thermal plasma reactor. Finally, a scalability study points at a possible use of the new disruptive process design at small scale, and possible industrial transformation scenarios for a distributed production at a local site of consumption are depicted.

中文翻译：

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一种新型等离子体辅助可持续工艺与液态金属联合生产氨和氢的热力学潜力

摘要 在本文中，研究了用于联合生产氨和氢的可持续等离子体辅助固氮工艺的热力学潜力。开发的工艺利用化学循环系统，通过使用液态金属（如镓）驱动固氮反应，使用三个反应器，包括反应器 R1 从镓和氮生产氮化镓，反应器 R2 从氮化镓生产氨和氢，以及等离子体反应器 R3 将氧化镓转化为纯镓。热力学评估的结果表明，所提出的反应是自发的，并且在反应器中发生是可行的。同样，前两个反应是放热的，反应器 R1 和 R2 中的 Δ H = - 230 k J mol 和 Δ H = - 239 k J mol，分别具有 100% 的平衡化学转化率。等离子体反应器需要热能来驱动氧化镓离解的吸热反应，Δ H = + 870 k J mol 。热化学平衡分析表明，蒸汽与 GaN 的摩尔比以及反应器 R2 的操作压力和温度是确定反应器中产物组成的主要操作参数，因此通过提高温度，氢与氨的摩尔比增加。但是，通过将蒸汽/GaN 的摩尔比（φ 值）从 0.1 增加到 1，反应器的氢含量在 400 °C 时从 45% 增加到 70%。对于 φ > 1.0，氢含量降低，而更多的氢参与了 NH3 的形成，从而增加了反应器中氨的摩尔分数。由于液态金属基反应的高度负吉布斯自由能以及热等离子体反应器支持的大热驱动力，预计所有三个反应器的平衡化学转化都将达到完成点（χ = 100%）。最后，一项可扩展性研究指出了在小规模下可能使用新的颠覆性流程设计，并描述了在当地消费场所进行分布式生产的可能的工业转型场景。