Plasma-assisted ammonia synthesis in a packed-bed dielectric barrier discharge reactor:roles of dielectric constant and thermal conductivity of packing materials  

作　　者：Jin LIU Xinbo ZHU Xueli HU Xin TU 刘进;竺新波;胡学理;屠昕(Faculty of Maritime and Transportation,Ningbo University,Ningbo 315211,People's Republic of China;Department of Electrical Engineering and Electronics,University of Liverpool,Liverpool L693GJ,United Kingdom)

机构地区：[1]Faculty of Maritime and Transportation,Ningbo University,Ningbo 315211,People's Republic of China [2]Department of Electrical Engineering and Electronics,University of Liverpool,Liverpool L693GJ,United Kingdom

出　　处：《Plasma Science and Technology》2022年第2期127-136,共10页等离子体科学和技术（英文版）

基　　金：the financial support from National Natural Science Foundation of China(No.51976093);K C Wong Magna Fund in Ningbo University。

摘　　要：In this article,plasma-assisted NH;synthesis directly from N;and H;over packing materials with different dielectric constants(BaTiO_(2),TiO_(2) and SiO_(2))and thermal conductivities(Be O,Al N and Al_(2)O_(2))at room temperature and atmospheric pressure is reported.The higher dielectric constant and thermal conductivity of packing material are found to be the key parameters in enhancing the NH;synthesis performance.The NH;concentration of 1344 ppm is achieved in the presence of BaTiO_(2),which is 106%higher than that of SiO_(2),at the specific input energy(SIE)of 5.4 k J·l^(-1).The presence of materials with higher dielectric constant,i.e.BaTiO_(2) and TiO_(2)in this work,would contribute to the increase of electron energy and energy injected to plasma,which is conductive to the generation of chemically active species by electron-impact reactions.Therefore,the employment of packing materials with higher dielectric constant has proved to be beneficial for NH;synthesis.Compared to that of Al_(2)O_(3),the presence of Be O and Al N yields 31.0%and 16.9%improvement in NH;concentration,respectively,at the SIE of5.4 k J·l^(-1).The results of IR imaging show that the addition of Be O decreases the surface temperature of the packed region by 20.5%to 70.3℃ and results in an extension of entropy increment compared to that of Al_(2)O_(3),at the SIE of 5.4 k J·l^(-1).The results indicate that the presence of materials with higher thermal conductivity is beneficial for NH;synthesis,which has been confirmed by the lower surface temperature and higher entropy increment of the packed region.In addition,when SIE is higher than the optimal value,further increasing SIE would lead to the decrease of energy efficiency,which would be related to the exacerbation in reverse reaction of NH;formation reactions.

关 键 词：dielectric barrier discharge ammonia synthesis packing materials thermal conductivity dielectric constant 

分 类 号：O539[理学—等离子体物理]