合成氣重組製造甲醇及乙醇之研究

Synthesis of Methanol and Ethanol from Syngas

洪培堯(Pei-Tao Hung)

指導教授 ： 張慶源

國立臺灣大學/工學院/環境工程學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.02596

摘要

本研究開發合成氣重組製造燃料及化學品之相關應用技術，以協助解決國內有機或生質廢棄物所造成之環境問題，並將其轉化為能源燃料，期能提供國內分散式能源供應的技術能量。

本研究使用高溫高壓液化設備將合成氣(CO及H2)轉化成液體產物，比較添加Pt/γ-Al2O3及MoS2/γ-Al2O3觸媒催化以增進醇類生成選擇率之結果。由實驗結果顯示，比較乾式無添加觸媒(dry syngas liquefaction, DSL)、白金觸媒(Pt/γ-Al2O3 dry catalytic syngas liquefaction, DCSL-Pt)及二硫化鉬(MoS2/γ-Al2O3 dry catalytic syngas liquefaction, DCSL-Mo)三程序，當進料之CO及H2分別為4.77及0.68 g時，比較473、523、573及593 K反應溫度，反應時間一小時之結果顯示DSL於T = 593 K可得235 μg CH4為最佳值；DCSL-Pt於T = 573 K可得68.3 μg CH3OH為最佳值；DCSL-Mo於T = 573 K可得208 μg C2H5OH為最佳值。並添加水分以增加氫氧來源下，其對醇類生成及收集之影響，於水式(hydro-)合成氣液化HSL、HCSL-Pt及HCSL-Mo三程序中，結果顯示HCSL-Pt於T = 593 K可得2,575 μg CH3OH為最佳值；HCSL-Mo於T = 593 K可得128 μg CH4 及6,590 μg C2H5OH為最佳值、於T = 573及523 K時分別得808 μg C3H7OH及11,874 μg other HC-MOH皆為最佳值。並比較乾式及水式各程序，結果顯示於系統中添加水份除可助收集醇類外，水份之添加可明顯減少CH4之產生，有效增進CH3OH、C2H5OH甚至更高碳數之碳氫化合物之產生。

增加添加水量時，除了可以抑制甲烷產生進而增加醇類產物生成以外，更由產物組成比例之變化，可得知水亦可扮演增進其產物選擇性之角色，大幅增進觸媒催化效用。對於CH3OH產率而言，HCSL-Pt程序中添加6 mL H2O催化液化，於T = 573 K時可得6,204 μg為最佳值，相當於同條件下DCSL-Pt程序產生68.3 μg之90倍。對於C2H5OH產率而言，HCSL-Mo程序中添加6 mL H2O催化液化，於T = 573 K時可得8,139 μg之為最佳值，相當於同條件下DCSL-Mo程序產生208 μg之39倍。

關鍵字

合成氣 ； 液化 ； MoS2/γ-Al2O3 ； Pt/γ-Al2O3 ； 水式

並列摘要

Bio-energy is now accepted as having a potential to provide a significant portion of the projected renewable energy provisions of the future. Therefore, biomass waste is one of the bio-energy sources and can be reused as a fuel or as a raw material to produce chemical feedstocks.

This study examined the feasibility and operation performance of reaction and liquefaction of syngas (CO and H2) (denoted as SL process), and the enhancement effects of addition of MoS2/γ-Al2O3 and Pt/γ-Al2O3 catalysts (noted as CSL-Mo and CSL-Pt processes, respectively) to increase the yields and selectivities of alcohols generated. For the cases at 473, 523, 573 and 593 K for 1 hr with feeding gas consisting of CO and H2 of 4.77 and 0.68 g, respectively, the DSL process operated at 593 K yields the highest production of CH4 of 235 μg, the DCSL-Pt process at 573 K gives the highest production of CH3OH of 68.3 μg and the DCSL-Mo process at 573 K offers the highest production of C2H5OH of 208 μg. The presence of H2O (called as hydro-process or H-process) assists the generation and collection of alcohols. The results show that the use of Pt/γ-Al2O3 catalyst in the HSL process noted as HCSL-Pt process enhances the formation of CH3OH, giving the highest production of 2,575 μg at 593 K for 1 hr. For the case via the hydro MoS2/γ-Al2O3 process (denoted as HCSL-Mo), it yields the highest productions of 128 μg of CH4 and 6,590 μg of C2H5OH at 593 K. Thus, the addition of H2O enhances the production of alcohols by reducing the generation of CH4.

Further, the increase of the addition of H2O in H-process also plays a role to promote the selectivity and enhance the catalytic effectiveness of catalysts, changing the composition of products. Regarding the production of CH3OH, the HCSL-Pt process with 6 mL H2O gives the highest production of 6,204 μg at 573 K, which is about 90 times of that via the DCSL-Pt process. Aiming at C2H5OH, the HCSL-Mo process with 6 mL H2O yields the highest production of 8,139 μg at 573K, which is 39 times of that via the DCSL-Mo process.

並列關鍵字

Syngas ； liquefaction ； MoS2/γ-Al2O3 ； Pt/γ-Al2O3

參考文獻

Bhasin, M. M., W. J. Bartlev, P. C. Ellqen, T. P. Wilson, Synthesis gas conversion over supported rhodium and rhodium-iron catalysts, J. Catal, 54(2), 120-128(2008).

Bowker, M., On the mechanism of ethanol synthesis on rhodium, Catal. Today, 15(1), 77-100 (1992).

Chuang, S. C., J. G. Goodwin and I. Wender, The effect of alkali promotion on CO hydrogenation over Rh/TiO2, J. Catal., 95(2), 435-446 (1985).

Forzatti. P., E. Tronconi and I. Pasquon, Higher alcohol synthesis, Cataly Rev., 33(1&2), 109-168 (1991).

Hamada, H, Y. Kuwahara, Y. Kintaichi, T. Ito, K. Wakabayashi, H. Iijima and K. Sano, Construction of the C46-C55 fragment of ciguatoxin, Chem. Lett., 23(9), 1611-1612 (1984).