Dielectric characterization of bentonite clay at various moisture contents and with mixtures of biomass in the microwave spectrum
Dielectric characterization of bentonite clay at various moisture contents and with mixtures of biomass in the microwave spectrum
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DOI：
10.1080/08327823.2017.1421407
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发表时间：
2018-01-01
影响因子：
1.5
通讯作者：
Boldor, Dorin
中科院分区：
文献类型：
--
作者：
Ellison, Candice;McKeown, Murat Sean;Boldor, Dorin
本研究评估了使用膨润土作为微波辅助生物质热解的微波吸收剂的介电性能的基础上的潜力。由于膨润土是一种吸湿材料，结合水含量对介电性能的影响在这项研究中得到解决。用同轴线介电探针和矢量网络分析仪在室温下测量了不同含水率的膨润土在0.2 ~ 4.5GHz微波频率范围内的介电性能。此外，从1.5至20 GHz测量膨润土与生物质的混合物的介电性质，因为膨润土与生物质的混合物可以具有微波加工应用，例如生物质到生物燃料的热化学转化。介电常数和介电损耗因子均随含水量的增加而线性增加。生物质和膨润土混合物的测量表明，随着膨润土含量的增加，介电常数和损耗因子呈二次增加，含水量范围从9.5%（纯膨润土）到11.4%（纯生物质）湿基。在915 MHz，介电常数范围从2.0到6.2和介电损耗范围从0.2到2.7，分别。在2450 MHz，介电常数范围从1.8到5.1和介电损耗范围从0.7到2.6，分别。
This study assesses the potential for using bentonite as a microwave absorber for microwave-assisted biomass pyrolysis based on the dielectric properties. As bentonite is a hygroscopic material, the effect of bound water content on dielectric properties was addressed in this study. Dielectric properties of bentonite at different moisture contents were measured using a coaxial line dielectric probe and vector network analyser in the microwave frequency range from 0.2 to 4.5 GHz at room temperature. Further, dielectric properties of mixtures of bentonite with biomass were measured from 1.5 to 20 GHz as mixtures of bentonite with biomass could have microwave processing applications such as the thermochemical conversion of biomass to biofuel. Both dielectric constant and dielectric loss factor increased linearly with increasing moisture content. Measurements on biomass and bentonite mixtures show a quadratic increase in dielectric constant and loss factor with increasing bentonite content and with moisture contents ranging from 9.5% (pure bentonite) to 11.4% (pure biomass) wet basis. At 915 MHz, dielectric constant ranged from 2.0 to 6.2 and dielectric loss ranged from 0.2 to 2.7, respectively. At 2450 MHz, dielectric constant ranged from 1.8 to 5.1 and dielectric loss ranged from 0.7 to 2.6, respectively.