Abstract

Reforming of fossil fuels coupled with carbon capture and storage has the potential to produce low-carbon H₂ at large scale and low cost. Adsorption is a potentially promising technology for two key separation tasks in this process: H₂ purification and CO₂ capture. In this work, we present equilibrium adsorption data of H₂ and CH₄ on zeolite 13X, in addition to the already established CO₂ isotherms. Further, we carry out binary (CO₂–CH₄) and ternary (H₂–CO₂–CH₄) breakthrough experiments at various pressures and temperatures to estimate transport parameters, assess the predictive capacity of our 1D column model, and compare different multi-component adsorption models. CO₂ adsorbs strongly on zeolite 13X, CH₄ adsorbs less, and H₂ adsorbs very little. Thus, H₂ breaks through first, CH₄ second (first in the binary breakthrough experiments) and CO₂ last. Linear driving force (LDF) mass transfer coefficients are estimated based on a single breakthrough experiment and mass transfer is found to be fast for H₂, slower for CH₄, and slowest for CO₂. The LDF parameters can be used in a predictive manner for breakthrough experiments at varying pressures, temperatures, flows, and, though with lower accuracy, even compositions. Heat transfer inside the column is described well with a literature correlation, thus yielding an excellent agreement between simulated and measured column temperatures. Ideal and real adsorbed solution theories (IAST and RAST, respectively) both model the observed breakthrough composition profiles well, whereas extended isotherms are inferior for predicting the competitive behavior between CH₄ and CO₂ adsorption. This study provides the groundwork necessary for full cyclic experiments and their simulation.

中文翻译：

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高效低碳氢生产的吸附：第1部分：H 2 / CO 2 / CH 4在13X沸石上的吸附平衡和穿透研究

摘要

化石燃料的重整以及碳的捕集和封存具有大规模大规模生产低成本低碳H ₂的潜力。对于此过程中的两个关键分离任务，吸附是一种潜在有前途的技术：H ₂纯化和CO ₂捕获。在这项工作中，除了已经建立的CO ₂等温线外，我们还提供了H ₂和CH ₄在13X沸石上的平衡吸附数据。此外，我们执行二元（CO ₂ -CH ₄）和三元（H ₂ -CO ₂ -CH ₄）在各种压力和温度下的突破性实验，以估算运输参数，评估我们的一维色谱柱模型的预测能力，并比较不同的多组分吸附模型。CO ₂强烈吸附在13X沸石上，CH ₄吸附较少，而H ₂吸附很少。因此，H ₂首先突破，CH ₄第二突破（在二元穿透实验中首先突破），CO ₂最终突破。线性驱动力（LDF）传质系数是基于单个突破实验估算的，发现传质H ₂快，CH ₄慢，CO ₂慢。LDF参数可以预测性地用于在压力，温度，流量变化的情况下进行突破性实验，尽管精度较低，但组成均匀。很好地描述了色谱柱内部的传热，并结合了文献资料，因此在模拟和测量的色谱柱温度之间取得了极好的一致性。理想和实际吸附溶液理论（分别为IAST和RAST）都可以很好地模拟观察到的突破成分分布，而扩展的等温线对于预测CH ₄和CO ₂吸附之间的竞争行为则较差。这项研究为全循环实验及其模拟提供了必要的基础。