Tseng Fan-Gang, Chiu Wei-Cheng, Huang Po-Jung
Department of Engineering and System Science, National Tsing Hua University, Hshinchu 300, Taiwan.
Micromachines (Basel). 2023 Sep 27;14(10):1845. doi: 10.3390/mi14101845.
This paper proposes a Swiss-roll-type mini-reformer employing a copper-zinc catalyst for high-efficient SRM process. Although the commercially available copper-zinc catalysts commonly used in cylindrical-type reformers provide decent conversion rates in the short term, their long-term durability still requires improvement, mainly due to temperature variations in the reformer, catalyst loading, and thermal sintering issues. This Swiss-roll-shaped mini-reformer is designed to improve thermal energy preservation/temperature uniformity by using dual spiral channels to improve the long-term durability while maintaining methanol-reforming efficiency. It was fabricated on a copper plate that was 80 mm wide, 80 mm long, and 4 mm high with spiral channels that were 2 mm deep, 4 mm wide, and 350 mm long. To optimize the design and reformer operation, the catalyst porosity, gas hourly speed velocity (GHSV), operation temperature, and fuel feeding rate are investigated. Swiss-roll-type reformers may require higher driving pressures but can provide better thermal energy preservation and temperature uniformity, posing a higher conversion rate for the same amount of catalyst when compared with other geometries. By carefully adjusting the catalyst bed porosity, locations, and catalyst loading amount as well as other conditions, an optimized gas hourly space velocity (GHSV) can be obtained (14,580 mL/g·h) and lead to not only a high conversion rate (96%) and low carbon monoxide generation rate (0.98%) but also a better long-term durability (decay from 96% to 88.12% after 60 h operation time) for SRM processes. The decay rate, 0.13%/h, after 60 h of operation, is five-folds lower than that (0.67%/h, 0.134%/h) of a commercial cylindrical-type fixed-bed reactor with a commercial catalyst.
本文提出了一种采用铜锌催化剂的瑞士卷式微型重整器，用于高效的蒸汽重整制氢（SRM）过程。尽管圆柱形重整器中常用的市售铜锌催化剂在短期内能提供不错的转化率，但其长期耐久性仍需改进，主要原因在于重整器内的温度变化、催化剂装填以及热烧结问题。这种瑞士卷形状的微型重整器旨在通过使用双螺旋通道来改善热能保存/温度均匀性，从而在保持甲醇重整效率的同时提高长期耐久性。它是在一块宽80毫米、长80毫米、高4毫米的铜板上制造的，螺旋通道深2毫米、宽4毫米、长350毫米。为了优化设计和重整器运行，对催化剂孔隙率、气体时空速（GHSV）、运行温度和燃料进料速率进行了研究。瑞士卷式重整器可能需要更高的驱动压力，但能提供更好的热能保存和温度均匀性，与其他几何形状相比，在相同量催化剂的情况下具有更高的转化率。通过仔细调整催化剂床层孔隙率、位置、催化剂装填量以及其他条件，可以获得优化的气体时空速（GHSV）（14580毫升/克·小时），这不仅能实现高转化率（96%）和低一氧化碳生成率（0.98%），还能使SRM过程具有更好的长期耐久性（运行60小时后从96%衰减至88.12%）。运行60小时后的衰减率为0.13%/小时，比使用商业催化剂的商业圆柱形固定床反应器的衰减率（0.67%/小时、0.134%/小时）低五倍。
