Browsing by Subject "Non-thermal plasma"

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    Sustainable atmospheric ammonia synthesis and nitrogen fixation using non-thermal plasma (NTP)
    (2018-10) Peng, Peng
    Ammonia has recently been intensively studied as a clean, sustainable fuel source and an efficient energy storage medium due to its effectiveness as a hydrogen carrier molecule. However, the current method of ammonia synthesis, known as the Haber-Bosch process, requires a large fossil fuel input, high temperatures and pressures, as well as a significant capital investment. These volatile conditions and high operating costs prevent decentralized and small-scale ammonia production at the level of small farms and local communities. Non-thermal plasma technology represents a promising alternative method of clean ammonia synthesis, as it circumvents the volatile operating conditions, fossil fuel use, and high capital costs of the Haber-Bosch process. In this thesis research, this emerging technology was realized at the bench scale and was optimized by various efforts, including catalyst improvement, system development, and absorption enhancement. For the catalyst improvement, a multi-functional catalyst was introduced and deposited onto various supporting materials. For absorption enhancement, MgCl2 was implemented for the absorption enhancement, taking advantage of its capability of forming Mg3N2 and Mg(NH3)6Cl2 during the process. Meanwhile, the pulse density modulation (PDM) was introduced to improve the performance of system. The series of efforts improved the energy efficiency of the system by approximately one fold compared with previous studies, and achieved the highest value of 20 g/kwh. Furthermore, an innovative plasma gas-liquid ammonia synthesis approach was explored. It was found that this approach could produce other nitrogen compounds (nitrate and nitrite acids) while generating ammonium, which could potentially add value to the products of the plasma-assisted ammonia synthesis process. Based on the results, the challenges and future opportunities of the plasma-assisted ammonia synthesis approach were discussed. Lastly, recommendations were made on how this technology could be beneficial to the ammonia industry, through its potential to promote localized and environmentally friendly energy production and storage.