甲醇蒸汽重組反應可透過蒸發的甲醇水通過觸媒進行吸熱產氫，不僅氫氣生產效率較高，反應在相對較低的溫度就可以進行，可達到較高的熱效率，但入口因吸熱局部降溫、後段高溫的現象會造成反應集中在未達最佳反應溫度的入口，且高溫的後段不但使用效率低，也會容易超出觸媒使用溫度而使觸媒失效。另外產氫主要應用為供應燃料電池的原料，有效降低重組反應產物中的一氧化碳濃度為最重要的設計因素之一，若一氧化碳濃度低可避免燃料電池電極因毒化而無法使用，而在甲醇蒸汽重組反應中一氧化碳會傾向在高溫時生成。
為了達到良好的溫度分布避免上述的問題，本研究採用中心直接埋設熱管的堆疊床式甲醇蒸汽重組器，重組器材質選擇紅銅管，透過陶瓷電熱片取代燃燒加熱，著重在不同甲醇水流量、水碳比和觸媒溫度下熱管於重組器內的效果；經多個測溫點和重複性測試後，熱管重組器可在不同流量下達到後段觸媒和熱管本身溫差維持5度內，於入口流速2 ml/min、水碳比1.5及觸媒溫度250℃下，甲醇轉化率約70%，一氧化碳濃度約2~3%。和同樣重組器但中央為無效熱管的結果比較，其結果顯示雖然甲醇轉化率仍可在低流速、觸媒溫度250℃下維持在約70%，但由於無效熱管重組器本身的軸向傳熱不佳，使得後段觸媒及重組器中心都較高溫，整體一氧化碳濃度上升至約4~6%。為了研究是否為嵌入熱管造成渠道現象(channeling effect)造成低流速時仍無法達到高甲醇轉化率，另外和管徑、長度相差不多的中央無熱管重組器比較，結果可發現無熱管重組器的最佳甲醇轉化率只有約60%，因此整體重組器表現並非受到熱管設置造成渠道現象影響。
由三種甲醇重組器實驗結果可知，整體表現受觸媒顆粒大小及反應器幾何尺寸影響極大，而無法在測試條件下達到高甲醇轉化率；在同樣重組器尺寸、觸媒堆疊方式、流道方向和實驗條件下，嵌入熱管重組器和其他設計比較，可在理想反應溫度下抑制後段觸媒升溫，因此可維持同樣的甲醇轉化率並使一氧化碳下降，然而在低反應溫度或蒸發熱上升時反而會因熱管吸熱過多而使轉化率下降。

Tubular packed-bed methanol steam reformer (MSR) is widely applied for simple and efficient hydrogen production under a relatively low temperature. However, the low thermal conductivity of the catalyst pellets leads to poor temperature uniformity over the reactor. Low temperature occurs at the front section of the reactor due to stronger local endothermic reaction and high temperature at the back section. Thus, the reaction would occur out of the optimal range of reaction temperature, and the temperature at the back section might exceed the limit temperature of the catalyst. In addition, the product concentration of the poisoning carbon monoxide, which tends to generate at high temperature, may be undesirably high.
To achieve uniform temperature distribution for better performance, an MSR is embedded with a heat pipe along the center of the reformer. The reformer container is made of copper tubes and is heated by a ceramic heater. A number of thermocouples are inserted into the reformer to measure the temperatures of the catalyst and the heat pipe at different locations. We aim to observe the effect of the heat pipe under different flow rates, steam carbon ratios and packed-bed temperature. The longitudinal temperature differences of the catalyst can be maintained within a difference of 5 K at different test conditions. The methanol conversion is around 70% and the CO concentration is about 2-3%. When the heat pipe is deactivated, poorer longitudinal temperature uniformity is shown and the carbon monoxide concentration grows to 4-6%, with similar methanol conversion of about 70%. To examine whether the relative low conversion at low flow rate is due to the channeling effect around the embedded heat pipe, a similar MSR, except without a heat pipe is tested. The results shows that the best methanol conversion rate is only about 60%; consequently, the overall MSR performance is not affected by the channeling effect due to heat pipe implantation.
From the experimental results, the overall MSR performance is greatly affected by the catalyst particles size and the geometry of the reactor, and it leads to the low methanol conversion rates under the test conditions. Comparing heat pipe-embedded MSR with the others under the same MSR size, catalyst stacking, flow direction and test conditions, the heat pipe-embedded MSR can suppress the heating of the rear packed-bed , maintaining the same level of the methanol conversion rate and reduce the carbon monoxide concentration at the ideal reaction temperature, but the methanol conversion rate will drop when the reaction temperature is low or the heat of evaporation rises due to excessive heat absorption by the heat pipe.

[1] M.-R.d. Valladares, Global Trends and Outlook for Hydrogen, in, http://ieahydrogen.org/pdfs/Global-Outlook-and-Trends-for-Hydrogen_WEB.aspx, pp. Retrieved December 19, 2018.
[2] M.v.d. Hoeven, Technology Roadmap Hydrogen and Fuel Cells, in, https://www.iea.org/publications/freepublications/publication/TechnologyRoadmapHydrogenandFuelCells.pdf, pp. Retrieved December 19, 2018.
[3] A. Iulianelli, P. Ribeirinha, A. Mendes, A. Basile, Methanol steam reforming for hydrogen generation via conventional and membrane reactors: A review, Renewable and Sustainable Energy Reviews, 29 (2014) 355-368.
[4] D. Li, X. Li, J. Gong, Catalytic Reforming of Oxygenates: State of the Art and Future Prospects, Chemical Reviews, 116(19) (2016) 11529-11653.
[5] J.G. Sandra Curtin Fuel Cell Technologies Market Report 2016, in, https://www.energy.gov/sites/prod/files/2017/10/f37/fcto_2016_market_report.pdf, pp. Retrieved December 19, 2018.
[6] P.N.N. Laboratory, Pathways to Commercial Success: Technologies and Innovations Enabled by the U.S. Department of Energy Fuel Cell Technologies Office, in, https://www.energy.gov/sites/prod/files/2017/10/f37/fcto_2016_market_report.pdf, pp. Retrieved December 19, 2018.
[7] 洪長春, 微型燃料電池研發策略之專利佈局, in, https://portal.stpi.narl.org.tw/index/article/10304, pp. Retrieved December 19, 2018.
[8] W.Y. Wijaya, S. Kawasaki, H. Watanabe, K. Okazaki, Damköhler number as a descriptive parameter in methanol steam reforming and its integration with absorption heat pump system, Applied Energy, 94 (2012) 141-147.
[9] T. Durka, G.D. Stefanidis, T. Van Gerven, A.I. Stankiewicz, Microwave-activated methanol steam reforming for hydrogen production, International Journal of Hydrogen Energy, 36(20) (2011) 12843-12852.
[10] 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.
[11] S. Sá, H. Silva, L. Brandão, J.M. Sousa, A. Mendes, Catalysts for methanol steam reforming—A review, Applied Catalysis B: Environmental, 99(1) (2010) 43-57.
[12] S.T. Yong, C.W. Ooi, S.P. Chai, X.S. Wu, Review of methanol reforming-Cu-based catalysts, surface reaction mechanisms, and reaction schemes, International Journal of Hydrogen Energy, 38(22) (2013) 9541-9552.
[13] B.A. Peppley, J.C. Amphlett, L.M. Kearns, R.F. Mann, Methanol–steam reforming on Cu/ZnO/Al2O3. Part 1: the reaction network, Applied Catalysis A: General, 179(1) (1999) 21-29.
[14] B.A. Peppley, J.C. Amphlett, L.M. Kearns, R.F. Mann, Methanol–steam reforming on Cu/ZnO/Al2O3 catalysts. Part 2. A comprehensive kinetic model, Applied Catalysis A: General, 179(1) (1999) 31-49.
[15] 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.
[16] C.J. Jiang, D.L. Trimm, M.S. Wainwright, N.W. Cant, Kinetic mechanism for the reaction between methanol and water over a Cu-ZnO-Al2O3 catalyst, Applied Catalysis A: General, 97(2) (1993) 145-158.
[17] K. Takahashi, N. Takezawa, H. Kobayashi, The mechanism of steam reforming of methanol over a copper-silica catalyst, Applied Catalysis, 2(6) (1982) 363-366.
[18] B. Frank, F.C. Jentoft, H. Soerijanto, J. Kröhnert, R. Schlögl, R. Schomäcker, Steam reforming of methanol over copper-containing catalysts: Influence of support material on microkinetics, Journal of Catalysis, 246(1) (2007) 177-192.
[19] H. Purnama, T. Ressler, R.E. Jentoft, H. Soerijanto, R. Schlögl, R. Schomäcker, CO formation/selectivity for steam reforming of methanol with a commercial CuO/ZnO/Al2O3 catalyst, Applied Catalysis A: General, 259(1) (2004) 83-94.
[20] R.J. Farrauto, L. Dorazio, C.H. Bartholomew, Introduction to catalysis and industrial catalytic processes.
[21] M. Khzouz, J. Wood, B. Pollet, W. Bujalski, Characterization and activity test of commercial Ni/Al2O3, Cu/ZnO/Al2O3 and prepared Ni–Cu/Al2O3 catalysts for hydrogen production from methane and methanol fuels, International Journal of Hydrogen Energy, 38(3) (2013) 1664-1675.
[22] P.L. Mary-Rose de Valladares, IEA Hydrogen Vision and R,D&D: Current perspectives, future prospects, in, http://ieahydrogen.org/pdfs/IEA-Hydrogen-Fuel-EFC-2017-2.aspx, pp. Retrieved December 19, 2018.
[23] 羅凱帆, 王訓忠, 新型被動式進料甲醇蒸氣重組器之設計與研究 國立清華大學, 2012.
[24] 蕭皓中, 王訓忠, 以熱管均溫之富氫重組產物中一氧化碳移除研究 國立清華大學, 2012.
[25] F. Vidal Vázquez, P. Simell, J. Pennanen, J. Lehtonen, Reactor design and catalysts testing for hydrogen production by methanol steam reforming for fuel cells applications, International Journal of Hydrogen Energy, 41(2) (2016) 924-935.
[26] 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.
[27] J.-S. Suh, M.-T. Lee, R. Greif, C.P. Grigoropoulos, Transport phenomena in a steam-methanol reforming microreactor with internal heating, International Journal of Hydrogen Energy, 34(1) (2009) 314-322.
[28] T. Kim, Micro methanol reformer combined with a catalytic combustor for a PEM fuel cell, International Journal of Hydrogen Energy, 34(16) (2009) 6790-6798.
[29] G. Avgouropoulos, A. Paxinou, S. Neophytides, In situ hydrogen utilization in an internal reforming methanol fuel cell, International Journal of Hydrogen Energy, 39(31) (2014) 18103-18108.
[30] N. Blet, S. Lips, V. Sartre, Heats pipes for temperature homogenization: A literature review, Applied Thermal Engineering, 118 (2017) 490-509.
[31] D. Reay, A. Harvey, The role of heat pipes in intensified unit operations, Applied Thermal Engineering, 57(1) (2013) 147-153.
[32] R.A.M.L. Mccallister, NJ), Reformer employing finned heat pipes, in, Foster Wheeler Energy Corporation (Livingston, NJ), United States, 1982.
[33] D.B. Edlund, OR, US), Portable fuel cell system, in, Protonex Technology Corporation (Southborough, MA, US), United States, 2009.
[34] M.-j.Y.-s. Oh, KR), Fuel cell system with heat transferor and fuel tank and method of driving the same, in, Samsung SDI Co., Ltd. (Yongin-si, Gyeonggi-do, KR), United States, 2013.
[35] J.E.D. Brantley, CA, US), Kaye, Ian W. (Livermore, CA, US), Derenzi, Michael C. (San Ramon, CA, US), Di Scipio, William (Fremont, CA, US), Heat efficient portable fuel cell systems, in, UltraCell Corporation (Livermore, CA, US), United States, 2011.
[36] 花誠陽, 甲醇-水蒸汽重組產氫與一氧化碳甲烷化觸媒開發之實驗探討, 國立中興大學, 2014.
[37] C. Liao, P.A. Erickson, Characteristic time as a descriptive parameter in steam reformation hydrogen production processes, International Journal of Hydrogen Energy, 33(6) (2008) 1652-1660.
[38] 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.