Mendel Niels, Boon Jordanus J P Jordi, Sîreţanu Igor, Mugele Frieder, Brilman Derk W F Wim
Physics of Complex Fluids, Faculty of Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Sustainable Process Technology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Ind Eng Chem Res. 2025 Apr 10;64(16):8359-8374. doi: 10.1021/acs.iecr.4c04491. eCollection 2025 Apr 23.
Biogas upgrading by vacuum-pressure swing adsorption involves the selective adsorption of CO over CH on a sorbent material to separate both components. This work assesses numerically the performance of the previously characterized Cs-exchanged bentonite clay for this separation. This benchmarking study includes the effect of the process cycle configuration (seven different configurations using one stage and up to three columns), the ambient temperature (15 or 25 °C), the feed biogas composition (CO mole fraction of 0.35 or 0.45, balance CH), and the process operating parameters. Specific constraints on CH purity and CH recovery provide Pareto fronts for maximum productivity and minimum specific energy consumption. A two-column unit operated at ambient feed pressure can upgrade 0.097 Nm feed biogas (CO mole fraction of 0.45, balance CH) per kg sorbent per h to a bio-CH product with a purity of 0.906 and with a CH recovery of 0.967 at a comparatively low specific energy consumption of only 0.072 kWh per produced Nm of CH. Using more columns and pressure equalization steps further enhances the CH recovery. The low bentonite cost, the comparatively low specific energy consumption due to the favorable linear CO adsorption isotherms, and the high recovery due to the high CO/CH selectivity make Cs-bentonite an excellent alternative for conventional sorbent materials.
通过变压真空吸附法提升沼气品质涉及在吸附剂材料上对二氧化碳的选择性吸附，以分离这两种成分。本研究对先前表征的铯交换膨润土在这种分离过程中的性能进行了数值评估。这项基准研究包括工艺循环配置（使用一个阶段和多达三个塔的七种不同配置）、环境温度（15或25°C）、进料沼气组成（二氧化碳摩尔分数为0.35或0.45，其余为甲烷）以及工艺操作参数的影响。对甲烷纯度和甲烷回收率的特定限制为最大生产率和最小比能耗提供了帕累托前沿。在环境进料压力下运行的双塔装置，每千克吸附剂每小时可将0.097 Nm进料沼气（二氧化碳摩尔分数为0.45，其余为甲烷）提升为纯度为0.906、甲烷回收率为0.967的生物甲烷产品，且比能耗相对较低，每生产1 Nm甲烷仅为0.072 kWh。使用更多塔和压力均衡步骤可进一步提高甲烷回收率。膨润土成本低、由于有利的线性二氧化碳吸附等温线导致比能耗相对较低以及由于高二氧化碳/甲烷选择性导致回收率高，使得铯膨润土成为传统吸附剂材料的极佳替代品。
