Abstract

The new kinetically limited linear driving force (KLLDF) model was assessed against the traditional LDF model in the prediction of twelve different ternary and quaternary experimental breakthrough curves. These breakthrough curves comprised mixtures of CO₂, N₂ and CH₄ in He adsorbed on carbon molecular sieve MSC 3 K 172 and were conducted at various pressures (30, 50 and 100 psia) and at ambient temperature. The LDF and KLLDF models were implemented in the dynamic adsorption process simulator (DAPS) with the loading dependent LDF mass transfer coefficients and the single gas equilibrium adsorption isotherms measured independently with gravimetric uptake experiments. To make the comparison between the LDF and the KLLDF models as fair as possible, they utilized the same set of thermodynamic and kinetic parameters in DAPS, with no adjustments to any of them. Both the LDF and KLLDF models provided reasonable predictions of the experimental breakthrough curves and in-bed temperature histories, with general trends of no CH₄ uptake, gradual N₂ uptake and fast CO₂ uptake. However, the KLLDF model always provided better predictions, especially when CO₂ was present. The results revealed that the traditional LDF model led to depressed adsorbed phase loadings of CO₂, thereby underpredicting its breakthrough time in all cases. This depression stemmed from the equilibrium loading in the LDF driving force of the LDF model depending on the gas phase partial pressure of each component outside the pore structure. In contrast, the KLLDF model corrects this issue by making the equilibrium loading in its LDF driving force dependent on the actual loading of each component inside the pore structure. In conjunction with the mixed gas extended Langmuir model, the KLLDF model is perhaps the more appropriate model to use instead of the LDF model for any multicomponent adsorbate-adsorbent systems, whether diffusion limited or not, since it reduces to the LDF model for systems that do not exhibit significant diffusional limitations.

中文翻译：

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用于预测扩散限制吸附突破曲线的新动力学限制线性驱动力模型的评估

 抽象的

新的动力学有限线性驱动力 (KLLDF) 模型与传统的 LDF 模型在 12 种不同的三元和四元实验突破曲线的预测中进行了评估。这些穿透曲线由吸附在碳分子筛 MSC 3 K 172 上的 He 中的 CO ₂ 、N ₂ 和 CH ₄ 混合物组成，并在不同压力下进行（ 30、50 和 100 psia) 和环境温度。 LDF 和 KLLDF 模型在动态吸附过程模拟器 (DAPS) 中实现，具有与负载相关的 LDF 传质系数和通过重力吸收实验独立测量的单一气体平衡吸附等温线。为了使 LDF 和 KLLDF 模型之间的比较尽可能公平，他们在 DAPS 中使用了同一组热力学和动力学参数，没有对它们进行任何调整。 LDF 和 KLLDF 模型都对实验突破曲线和床内温度历史进行了合理的预测，总体趋势是不吸收 CH​​ ₄ 、逐渐吸收 N ₂ 和快速吸收 CO < b5>吸收。然而，KLLDF 模型总是提供更好的预测，特别是当存在 CO ₂ 时。结果表明，传统的 LDF 模型导致 CO ₂ 的吸附相负荷降低，从而在所有情况下都低估了其突破时间。这种下降源于 LDF 模型的 LDF 驱动力中的平衡载荷，该平衡载荷取决于孔隙结构外部各组分的气相分压。相比之下，KLLDF 模型通过使其 LDF 驱动力中的平衡载荷取决于孔隙结构内每个组件的实际载荷来纠正此问题。 与混合气体扩展 Langmuir 模型相结合，对于任何多组分吸附物-吸附剂系统（无论扩散是否受限），KLLDF 模型可能是代替 LDF 模型更合适的模型，因为它可简化为以下系统的 LDF 模型：不表现出显着的扩散限制。