In methanol reforming, there are four major reactions. Among them, partial oxidation of methanol (POM) is an exothermic reaction that can reach steady state quickly without extra heat supply, and thus is suitable for being used in micro-channel reactors. Micro-channel reactors have advantages of low pressure drop, compact size, and fast in thermal and mass transfer. Based on our previous research, we have developed Cu/ZnO based catalysts modified by manganese which had great performance under POM reaction. Therefore, we used it in our micro-channels.
When coating catalysts onto the silicon based micro-channels, catalysts after calcinations would peel off. The loading amount of catalyst is one of the important factors that determine the efficiency of micro-reactors. As a result, it’s crucial to increase the amount of catalysts and coat them uniformly onto the micro-channels.
The catalysts were prepared by three different procedures: citrate-complex method, citrate-gel method and slurry method. We used micro and nano-structures inside micro-reactors to enhance the adhesion between catalysts and micro-channels. We also study the effect of catalyst loading, loading times, sizes of catalyst particles, depth of micro-channels and speed of reactant gases to the efficiency of micro-reactors.
We used slurry method to wash coat catalysts. Alumina sol (boehmite/bentonite) was selected as inorganic binder for the coating. In order to prevent extensive clog of catalyst particles inside the micro-channels, we increased the depth of channels from 25 μm to 100 μm, 200 μm and 300 μm for testing performances. It showed that the depth of 200 μm had the highest performance after repetitive loading of catalyst, which led to 63% of CMeOH and 3.7*10-6(mol/min) of hydrogen yield at 250℃.
After a series of comparisons, we knew that 200 μm deep channels without binders after repetitive loading had the best performance, which had 100% of CMeOH and 1.6*10-5(mol/min) of hydrogen yield at 250℃. To increase the reaction area of the catalyst layer, we tried to add micro-column structures to the channels. And we had adopted a new coating method to prevent clogs of catalyst in the micro-columns.
The FTIR spectra of product gases from the micro-reactors showed that the activity of the channels increased as the ratio of B/C decreased and temperature increased. And channels without binders had the best performance with little amount of byproduct.

在甲醇重組反應製氫中，總共有四個主要的分解反應，其中POM反應為一放熱反應，不需額外添加熱源即可達到穩定態(steady state)，有利於微型甲醇重組器系統之微小化。微型重組器相較於一般的固定式填充床，具有低壓降、體積精巧、快速的熱傳與質傳等優點。本實驗室已發展Cu/Mn/ZnO觸媒，其於甲醇部份氧化反應中具有極佳之效能，故延用此觸媒沉積於微型甲醇重組器中。
觸媒在沉積於矽基材為主的微流道上時，於煅燒後會有脆化剝落的情形發生，流道上的觸媒沉積量為主要影響反應器效能優劣的重要因素之一，因此如何將觸媒塗佈上流道增加觸媒量是一項重要的課題。本研究利用複合、膠體與泥漿法製備觸媒流佈於流道中，並以微米柱與奈米線等結構增加觸媒與流道間的吸附能力，期能提升反應器的反應效能，同時研究觸媒濃度、流佈次數、顆粒大小、流道深度及製程方式對於微流道反應系統的影響。
要產生良好的附著能力，必須於觸媒及矽基材間產生化學鍵結。先前的研究利用檸檬酸與酸洗後矽基材產生氫氧基(-OH)進行鍵結，但在高溫煅燒中檸檬酸裂解使得附著力下降。於是最後我們採用泥漿法(slurry method)，選用無機氧化鋁溶膠(boehmite/bentonite)作為黏著劑。為防止觸媒顆粒於流道內的阻塞，將流道深度加深至100、200及300 μm，並做重複流佈觸媒的比較，其中以200 μm經重複流佈觸媒後的反應性為最佳，於250℃下可達到63%的甲醇轉換率與3.7*10-6(mol/min)的氫氣產率。
由一系列參數的比較後，我們得知流道以200 μm，不添加黏著劑經重複流佈後擁有最佳的反應能力，在250℃下可達到100%的甲醇轉換率與1.6*10-5(mol/min)的氫氣產率。為避免微米柱造成觸媒的阻塞，我們採用新塗佈方式，硬膜製程代替傳統的觸媒流佈方式。經過傅立葉紅外線光譜儀分析以不同濃度製備之反應器的產物後，我們發現反應性隨B/C比例減少與溫度升高而增加，同時以不添加黏著劑的流道擁有最佳活性且最少副產物的生成。

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