研究改變催化劑、外在環境條件和燃料對於蒸氣重組反應的影響

Investigation of the effects of metals, oxides, operational conditions and fuels on the steam reforming

洪志城(Jeng-Han Wang)

指導教授 ： 王禎翰

國立臺灣師範大學/理學院/化學系/碩士(2011年)

摘要

本研究方向主要是以Co、Ni、Cu、Ru、Rh、Pd、Ag、Ir、Pd、Au這十種金屬為主的催化劑，探討不同條件下對反應的改變，主要方向有三個，第一個是支撐物的不同，第二個是外在環境的改變，我們在這邊主要是改變水和氧氣的比例，第三個則是改變燃料的選擇，利用上面所提到三種不同的條件，來探討在重組反應下的趨勢。我們實驗的方向分成三個部分：
第一部分我們主要探討支撐物在乙醇重組反應下的影響，我們使用SiO2、 Al2O3、Ce-Al2O3這三種不同金屬氧化物當作支撐物，並在相同條件下去進行實驗。討論三種金屬氧化物在氫氣產率上的差異。
第二部分則是討論外在環境的影響，這邊主要是利用水和氧氣的改變來進行討論，這邊細分三個部分 1.改變乙醇加水的比例利用Rh/Al2O3去進行一系列比較 2.則是利用Al2O3為支撐物去調控空氣的流量進行一系列的實驗， 3.則是將催化劑進行自發放熱反應，在這邊則是改變C/O ratio 的大小來探討其趨勢。
第三部分則是改變燃料，我們利用不同碳數的醇類當作燃料進行重組反應，討論氫氣產率對應在醇類上的不同。
綜合上面三個部分實驗我們可以得到一些明顯的趨勢，第一部分可以得知金屬氧化物的活性會影響到氫氣的產率大小，第二部分則是可以得知當水加入越多或是空氣流量越大也能提高氫氣的產率，第三部分則是可以知道說當醇類的碳數越少時對於氫氣產率越能提高。

關鍵字

蒸氣重組反應 ； 乙醇 ； 催化劑

並列摘要

Herein we experimentally investigate the reforming mechanism of alcohols to find the most efficient method for hydrogen production. The reforming behavior can be affected by three major catageories: composition of catalysts, operational condictions, and alcohols. First, we study the reforming of ethanol, a environmental friendly biomass, on a series of chemically related catalysts, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au) composited on Al2O3, SiO2, and CeO2. The catalytic trends of metals have been previously examined and show that group 11 metals (Cu, Ag, Au) help for the oxidation process, Co, Ni, Pd, and Pt gives the highest C2H4 yield, and Ru, Rh and Ir shows the highest hydrogen yield. In the present study, we further reveal influence from oxides that Al2O3 assists for dehydeation of ethanol forming C2H4, SiO2 is considered as an insert supporter, and CeO2, with high oxygen capacity, give the best reforming performance. Second, we examine the reforming behavior at various operational conditions. The result shows that hydrogen yield, conversion efficiency and C1 selectivity will be significantly improved as the oxidant reagents of O2 and H2O are increased. Furthermore, the reforming process becomes autothermal when O2 ratio is sufficiently high. Also, the C/O ratio has been optimized in the autothermal reforming process. Finally, we examined the performance of methanol, ethanol, 1-propanol, 3-propnaol, and 1-butanol reformings to study the effects from fuel. The result shows that the hydrogen yield decreases as the carbons of alcohols increase.

並列關鍵字

steam reforming ； ethanol ； catalyst

參考文獻

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