Novel Carrier Materials

Lead Research Organisation: Newcastle University
Department Name: Sch of Engineering

Abstract

Ammonia is an essential fertilizer which supports half the world's population. Its production consumes 3-5% of the world's natural gas resulting in 1% of greenhouse gas emissions (International Fertilizer Association, 2009). Improving ammonia synthesis conditions will reduce energy consumptions and costs. This could allow ammonia to be produced from renewable sources cost-competitively or be used as a hydrogen carrier (Philibert, 2017; Zamfirescu & Dincer, 2009).
Alkali hydrides such as LiH and BaH2 have shown promise towards these endeavours (Wang et al., 2017). When mixed with transition metals, they allow ammonia to be produced at milder conditions. Furthermore, in a chemical looping configuration they act as nitrogen carrier materials and achieve close to commercial rates at 1 bar and 300 C (Gao et al., 2018). However, its handling and preparation challenges its application. And the feasibility and viability of implementing such a catalyst is unproven.

The project will focus on developing novel carrier materials by elucidating the influences of microstructural control over chemical looping materials and designing novel configurations to intensify the process. Experimental work will be used to interpret the performance and control over the nitrogen carrying material. In parallel, experimental results will complement modelling work that will be used to assess the viability of the process. The end-goal is to create a high-performing process that can meet future industrial requirements.

Catalyst preparation techniques will be modified to accommodate the sensitive nature of the catalyst. Based on the preparation method, the microstructural interaction of the alkali metal and transition metal will be identified with surface imaging techniques. The findings will be used to identify and produce novel microstructures that will enhance the chemical looping reaction.

The range of reaction conditions and catalyst performance will be established experimentally. Results will be used to develop kinetic models that will shed light on the benefits of a dynamic ammonia process with nitrogen storage. Although transient ammonia processes have been studied previously, their use and viability are hampered by their solid nitrogen transport or storage.

Mathematical models of the reactor based on the reaction kinetics will be used to synthesize the novel ammonia unit. The model results will allow the reactor cycle to be designed, and a novel reactor configuration can be produced. The results of the unit's performance will be contrasted to commercial units and integrated into an ammonia plant to assess the viability of the process.

Gao, W., Guo, J., Wang, P., Wang, Q., Chang, F., Pei, Q., ... Chen, P. (2018). Production of ammonia via a chemical looping process based on metal imides as nitrogen carriers. Nature Energy, 3(12), 1067-1075. https://doi.org/10.1038/s41560-018-0268-z
International Fertilizer Association. (2009). Fertilizers , Climate Change and Enhancing Agricultural Productivity Sustainably. In IFA. Retrieved from http://www.fertilizer.org/content/download/22932/328667/version/1/file/2009_ifa_climate_change.pdf
Philibert, C. (2017). Producing ammonia and fertilizers: new opportunities from renewables. Retrieved from https://www.iea.org/media/news/2017/Fertilizer_manufacturing_Renewables_01102017.pdf
Wang, P., Chang, F., Gao, W., Guo, J., Wu, G., He, T., & Chen, P. (2017). Breaking scaling relations to achieve low-temperature ammonia synthesis through LiH-mediated nitrogen transfer and hydrogenation. Nature Chemistry, 9(1), 64-70. https://doi.org/10.1038/nchem.2595
Zamfirescu, C., & Dincer, I. (2009). Ammonia as a green fuel and hydrogen source for vehicular applications. Fuel Processing Technology, 90(5), 729-737. https://doi.org/10.1016/j.fuproc.2009.02.004

Publications

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