Kinetic Assessment of Light Hydrocarbons Separation over Fe-Doped 13X Composite Sorbents Under Multicomponent Feed Conditions
Kinetic Assessment of Light Hydrocarbons Separation over Fe-Doped 13X Composite Sorbents Under Multicomponent Feed Conditions
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DOI：
10.1021/acs.iecr.3c00620
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发表时间：
2023-07
期刊：
影响因子：
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通讯作者：
K. Baamran;J. D. L. Moreno;A. Rownaghi;Fateme Rezaei
中科院分区：
文献类型：
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作者：
K. Baamran;J. D. L. Moreno;A. Rownaghi;Fateme Rezaei
目前研究的用于低碳烯烃/烷烃分离的吸附剂通常存在选择性低的问题。此外，对这一重要分离的多组分分析在文献中通常被忽视。为了提高13X沸石的分离效率，我们开发了一系列Fe2O3/13X复合吸附剂，并用C2H4、C2H6、CH4和H2的二元、三元和多组分混合气体评价了它们的分离性能。在这些复合材料中，使用了不同负载量的纳米和微米Fe2O3粒子(NPs和MPS)，同时还将Fe离子交换到13X沸石结构中。在所有颗粒尺寸下，随着FexLoad的增加，裸吸附剂的微孔率和表面积都减小了。然而，Fe1(NPs)/13x虽然比表面积较小，但仍表现出较高的C2H4吸附容量和C2H4/C2H6选择性，这归因于其较高的表面电子转移性能，从而通过静电相互作用增强了其吸附性能。此外，Fe1在13X骨架中的引入使微孔通道变窄，从而促进了分子筛分作用，提高了对C2H4的选择性。动态吸附结果表明，在存在杂质气体(CH4和H2)的情况下，C2H4/(C2H6+CH4+H2)的选择性分别从4.10降低到3.84和3.20。然而，在所有进料条件下，C2H4/C2H6选择性在∼4时基本恒定。此外，Fe1(NPs)/13X对不同吸附组份的亲和力大小顺序为：C2H4>；C2H6>；CH4>；H2，而物种迁移速率主要取决于分子在13X分子筛孔内的扩散速率。
Current sorbents investigated for light olefin/paraffin separation usually suffer from low selectivity. Besides, multicomponent analysis of this important separation is usually overlooked in the literature. To enhance the separation efficiency of zeolite 13X, we developed a series of Fe2O3/13X composite sorbents and assessed their separation performance using binary, ternary, and multicomponent gas mixtures of C2H4, C2H6, CH4, and H2. In these composites, nano- and micro Fe2O3particles (NPs and MPs) with varied loadings were used, while Fe was also ion-exchanged into the 13X zeolite structure. The microporosity and surface area of the bare sorbent were reduced upon increasing Fexloading for all particle sizes. However, Fe1(NPs)/13X demonstrated a higher C2H4adsorption capacity and C2H4/C2H6selectivity despite its lower surface area, which was attributed to its higher surface electron transfer property that enhanced its adsorption performance via electrostatic interactions. Additionally, the incorporation of Fe1into the 13X framework resulted in narrowing of the micropore channels, thereby promoting the molecular sieving effect and improving the selectivity toward C2H4. The dynamic adsorption results revealed the reduction in C2H4/(C2H6+ CH4+ H2) selectivity in the presence of impurity gases (CH4and H2), from 4.10 to 3.84 and 3.20 for binary, ternary, and multicomponent gas mixtures, respectively. Nevertheless, the C2H4/C2H6selectivity was found to be roughly constant at ∼4 across all feed conditions. Moreover, the affinity of Fe1(NPs)/13X toward different adsorbates from the most adsorbed to the least adsorbed component was in the order of C2H4> C2H6> CH4> H2, while the rates of species transport were found to be primarily dependent on the rates of molecular diffusion within the pores of the 13X zeolite.