本研究使用以氫氧燃燒作為熱源之整合式甲醇蒸汽重組反應器，並在觸媒中心放置一熱管，以改善觸媒床內縱向不均溫之現象。本實驗設計兩種不同長寬比之反應器，以比較反應器內徑對於觸媒均溫性、甲醇轉化率及CO濃度之影響，同時比較兩種反應器在觸媒填充長度減半及破壞熱管使其失效後對於反應器性能的影響，其中觸媒填充長度減半後，以氧化鋁球填滿反應器後段空間。實驗在固定水與甲醇進料比S/C=1.5、不同溫度及不同進料流量(Qin)下進行。實驗結果發現，高長寬比之反應器在使用有效熱管、Qin=0.3 ml/min，甲醇轉化率可達100%、CO濃度1.26%，而相同觸媒填充重量、實驗條件下，低長寬比之反應器僅達88.5%甲醇轉化率、CO濃度1.3%，即高長寬比之反應器對於提高甲醇轉化率及降低CO濃度有正向效果，其因高長寬比反應器改善反應器徑向溫差，而熱管改善反應器縱向溫差。減少反應器內部觸媒填充長度或破壞熱管，兩者實驗條件皆會使兩種長寬比之反應器降低甲醇轉化率及提高CO濃度。各項實驗皆進行重複性驗證，觸媒床溫度及甲醇轉化率皆有良好的重複性，但CO濃度則重複性較差。

This study investigates the performance of an integrated packed-bed catalytic methanol steam-reformer heated by catalytic hydrogen combustion. A heat pipe is embedded in the center of the packed-bed reformer to improve the uniformity of the axial temperature of the reformer. Two systems with different aspect ratios are tested to compare the effect of reformer geometry on the catalyst temperature distribution, methanol conversion and CO concentration. In addition, the effects of halved catalyst-packed length and the ineffectiveness of the heat pipe are examined. The rear space of the reactor with halved catalyst-packed length is filled with inactive alumina spheres. The experiments are conducted under a fixed water/methanol ratio (S/C) of 1.5 but different average temperatures and methanol/water feed rates (Qin). The experimental results show that the high-aspect-ratio reformer can yield 100% methanol conversion and a product of 1.26% CO concentration using the heat pipe under a flow rate of Qin=0.3 ml/min. Under the same catalyst-packed weight and experimental conditions, the low-aspect-ratio reformer only yields 88.5% methanol conversion and 1.3% CO concentration. It means that high-aspect-ratio reformer favors methanol conversion and reduces CO concentration due to improved radial temperature uniformity. The inserted heat pipe further improves the axial temperature uniformity. Furthermore, if the catalyst-packed length is reduced or the heat pipe is deactivated, the methanol conversion and CO concentration are deteriorated for both reformers. All experiments are tested twice with good repeatability for the catalyst temperature distribution and methanol conversion. However, the repeatability for CO concentration is not as good.

[1] I. Staffell, D. Scamman, A. Abad, P. Balcombe, P. Dodds, P. Ekins, N. Shah, K. Ward, The role of hydrogen and fuel cells in the global energy system, Energy & Environmental Science, 12 (2018) .
[2] M. Al-Zaidi, R. Al-Khafaji, D. Al-Zubaidy, M. Mahmood, A review: Fuel cells types and their applications, International Journal of Scientific Engineering and Applied Science, 7 (2021) 375-390.
[3] O.Z. Sharaf, M.F. Orhan, An overview of fuel cell technology: Fundamentals and applications, Renewable and Sustainable Energy Reviews, 32 (2014) 810-853.
[4] K. Mazloomi, C. Gomes, Hydrogen as an energy carrier: Prospects and challenges, Renewable and Sustainable Energy Reviews, 16(5) (2012) 3024-3033.
[5] M. Balat, Potential importance of hydrogen as a future solution to environmental and transportation problems, International Journal of Hydrogen Energy, 33(15) (2008) 4013-4029.
[6] L. F. Brown, A comparative study of fuels for on-board hydrogen production for fuel-cell-powered automobiles, International Journal of Hydrogen Energy, 26(4) (2001) 381-397.
[7] H. Li, C. Ma, X. Zou, A. Li, Z. Huang, L. Zhu, On-board methanol catalytic reforming for hydrogen production-A review, International Journal of Hydrogen Energy, 46(43) (2021) 22303-22327.
[8] G. Garcia, E. Arriola, W.-H. Chen, M.D. De Luna, A comprehensive review of hydrogen production from methanol thermochemical conversion for sustainability, Energy, 217 (2021) 119384.
[9] G.G. Park, S.D. Yim, Y.G. Yoon, C.S. Kirn, D.J. Seo, K. Eguchi, Hydrogen production with integrated microchannel fuel processor using methanol for portable fuel cell systems, Catalysis Today, 110(1-2) (2005) 108-113.
[10] J. Agrell, H. Birgersson, M. Boutonnet, Steam reforming of methanol over a Cu/ZnO/Al2O3 catalyst: a kinetic analysis and strategies for suppression of CO formation, Journal of Power Sources, 106(1) (2002) 249-257.
[11] R.-Y. Chein, Y.-C. Chen, C.-M. Chang, J.N. Chung, Experimental study on the performance of hydrogen production from miniature methanol–steam reformer integrated with Swiss-roll type combustor for PEMFC, Applied Energy, 105 (2013) 86-98.
[12] C.J. Jiang, D.L. Trimm, M.S. Wainwright, N.W. Cant, Kinetic study of steam reforming of methanol over copper-based catalysts, Applied Catalysis A: General, 93(2) (1993) 245-255.
[13] L. Zhang, L.-W. Pan, C.-J. Ni, T.-J. Sun, S.-D. Wang, Y.-K. Hu, A.-J. Wang, S.-S. Zhao, Effects of precipitation aging time on the performance of CuO/ZnO/CeO2-ZrO2 for methanol steam reforming, Journal of Fuel Chemistry and Technology, 41(7) (2013) 883-888.
[14] A. Karim, J. Bravo, D. Gorm, T. Conant, A. Datye, Comparison of wall-coated and packed-bed reactors for steam reforming of methanol, Catalysis Today, 110(1) (2005) 86-91.
[15] S. Nagano, H. Miyagawa, O. Azegami, K. Ohsawa, Heat transfer enhancement in methanol steam reforming for a fuel cell, Energy Conversion and Management, 42 (2001) 1817-1829.
[16] D.D. Davieau, P.A. Erickson, The effect of geometry on reactor performance in the steam-reformation process, International Journal of Hydrogen Energy, 32(9) (2007) 1192-1200.
[17] H.C. Yoon, J. Otero, P.A. Erickson, Reactor design limitations for the steam reforming of methanol, Applied Catalysis B: Environmental, 75(3) (2007) 264-271.
[18] H. Ji, J. Lee, E. Choi, I. Seo, Hydrogen production from steam reforming using an indirect heating method, International Journal of Hydrogen Energy, 43(7) (2018) 3655-3663.
[19] R. Chein, Y.-C. Chen, J.N. Chung, Axial heat conduction and heat supply effects on methanol-steam reforming performance in micro-scale reformers, International Journal of Heat and Mass Transfer, 55(11) (2012) 3029-3042.
[20] P. Nehe, V.M. Reddy, S. Kumar, Investigations on a new internally-heated tubular packed-bed methanol–steam reformer, International Journal of Hydrogen Energy, 40(16) (2015) 5715-5725.
[21] P. Erickson, C.-H. Liao, Heat transfer enhancement of steam reformation by passive flow disturbance inside the catalyst bed, ASME Journal of Heat Transfer, 129 (2007) 995-1003.
[22] G. Arzamendi, P.M. Diéguez, M. Montes, M.A. Centeno, J.A. Odriozola, L.M. Gandía, Integration of methanol steam reforming and combustion in a microchannel reactor for H2 production: A CFD simulation study, Catalysis Today, 143(1) (2009) 25-31.
[23] J.M. Leimert, P. Treiber, J. Karl, The heatpipe reformer with optimized combustor design for enhanced cold gas efficiency, Fuel Processing Technology, 141 (2016) 68-73.
[24] J.R. McDonough, A.N. Phan, D.A. Reay, A.P. Harvey, Passive isothermalisation of an exothermic reaction in flow using a novel “Heat Pipe Oscillatory Baffled Reactor (HPOBR)”, Chemical Engineering and Processing: Process Intensification, 110 (2016) 201-213.
[25] S.-C. Wong, H.-C. Hsiao, K.-F. Lo, Improving temperature uniformity and performance of CO preferential oxidation for hydrogen-rich reformate with a heat pipe, International Journal of Hydrogen Energy, 39(12) (2014) 6492-6496.
[26] 林育愷，以熱管進行熱管理之填充床式甲醇蒸汽重組產氫整合系統，國立清華大學碩士論文, 2020.