| 摘要: | 中文摘要
本研究運用管式填充床反應器設計了甲醇水蒸氣重組（MSR）燃料電池，並採用
不同的工業觸媒Cu/ZnO/Al2O3 和CuO/ZnO/Al2O3，每種觸媒都有不同的反應速率公
式，本研究已使用實驗數據將其進行驗證。在模擬中，於Cu/ZnO/Al2O3 觸媒中採用
水蒸氣重組（SR）和逆水煤氣轉化（RWGS）反應，在CuO/ZnO/Al2O3 的模擬中，則
採用了水蒸氣重組（SR）、分解和水煤氣轉化（WGS）反應。
這些計算是由COMSOL 多重物理量耦合分析軟體進行的。分析了重組器入口溫
度、加熱管入口溫度、水碳比和入口空氣流速等參數。同時計算了溫度分佈、甲醇、
一氧化碳、二氧化碳、氫氣和水蒸氣的摩爾分率。最後從甲醇轉化率、CO 選擇性和
各氣體的摩爾分率等方面比較了不同觸媒的MSR 性能。
結果表明，對於Cu/ZnO/Al2O3 之觸媒，入口溫度為300℃時，重組器的甲醇轉化
率高達100%。然而，入口溫度的升高也使CO 含量增加，直至達到0.14%。另外，
由於逆水煤氣轉化反應（RWGS）將CO2 轉化為CO，降低了CO2 的摩爾分率。在同
一參數下，採用CuO/ZnO/Al2O3 的反應器，在入口溫度為180℃-200℃時，甲醇轉化
率達到100%，因使用了三種反應，故CO 之摩爾分率僅為0.05%。影響MSR 性能的
第二個參數是加熱管之入口風速，其在使用Cu/ZnO/Al2O3 的重組裝置中，進氣速率
由1m/s 增加到6m/s，可以使甲醇轉化率從10%提高到25%。其在另一種觸媒的效果
則較好，甲醇轉化率可達到80%，轉化率的提高與加熱管內之熱空氣的質量對流密切
相關，導致更多的熱量可以沿著重組器分佈。這也使得加熱管入口溫度的影響不太顯
著。當加熱管入風速率固定為0.1m/s 時，熱能傳遞不能為重組過程提供足夠的熱量。
將水碳比由0.7 增加至1.45，可以减少燃料稀釋產生的氫氣。
關鍵字：甲醇蒸汽重組、Cu / ZnO / Al2O3、CuO / ZnO / Al2O3、逆水煤氣轉化、水煤
氣轉化、COMSOL;ABSTRACT
Methanol Steam Reforming (MSR) with tubular packed bed reactor design was
developed for fuel cell using the different commercial catalyst Cu/ZnO/Al2O3 and
CuO/ZnO/Al2O3. Each catalyst has a different kinetic rate formula that has been validated
using experimental data. In simulation, using Cu/ZnO/Al2O3 catalyst uses Steam Reforming
(SR) and Reverse Water Gas Shifting (RWGS) reactions. Meanwhile, in simulation using
CuO/ZnO/Al2O3 uses Steam Reforming (SR), Decomposition and Water Gas Shifting (WGS)
reactions.
The calculation is carried out by a multiphysics program called COMSOL. Some of the
parameters are varied to be analyzed such as reformer inlet temperature, heating tubes inlet
temperature, steam to carbon and air heating tubes inlet velocity. Temperature distribution,
methanol (CH3OH), carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2) and steam
(H2O) mole fraction were calculated simultaneously. Finally, the performances of the MSR
using different catalyst are compared in terms of methanol conversion, CO selectivity and
mole fraction of each gases.
The results showed that the effect of reformer inlet temperature presenting high
methanol conversion until reach 100% at temperature inlet 300 ℃ for Cu/ZnO/Al2O3
catalyst. However, the increase of reformer inlet temperature also enhance of CO until
reaching 0.14%. Otherwise, it decreases CO2 mole fraction due to reverse water gas shift
reaction (RWGS) which convert CO2 to CO. Different results in the same parameter showed
for a reactor that using CuO/ZnO/Al2O3 which has achieved 100% methanol conversion at
reformer inlet temperature around 180 ℃ − 200℃ with CO mole fraction only 0.05%
because of the use of three reactions. The second parameter affects on the performance of
MSR is air heating tubes inlet velocity. The increasing air velocity inlet from 1 m/s to 6 m/s
can enhance the methanol conversion from 10% to 25 % in reformer using Cu/ZnO/Al2O3.
While, better results are obtained in another catalyst which is reached until 80% methanol
conversion. These increasing closely related to mass convection of hot air in heating tubes
that caused more heat could be distributed along reformer. This also causes effect of heating
tubes inlet temperature to be not too significant. With fixed parameter for air heating tubes
inlet velocity 0.1 m/s, the heat energy transfer cannot provide the enough heat for reforming
process. The increasing of steam to carbon from 0.7 to 1.45 can decrease the hydrogen
production due to the fuel dilution.
Keywords : Methanol Steam Reforming, Cu/ZnO/Al2O3, CuO/ZnO/Al2O3, Reverse Water
Gas Shifting, Water Gas Shifting, COMSOL |
