Evaluation on the efficiency of syngas generation from biogas via a hybrid plasma photocatalysis system
| Autor: | Wei-Chieh Chung, 鍾瑋杰 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 Biogas comes from the anaerobic digestion of organics and is composed of methane, carbon dioxide, water vapor and trace amount of hydrogen sulfide and ammonia. Biogas can serve as a fuel to generate energy, nevertheless, carbon dioxide reduces its heating value while H2S is corrosive to pipeline and boiler. Converting biogas into syngas and removing H2S can increase its heating value and the stability of combustion system. So far, available biogas reforming technologies include catalysis, photocatalysis and nonthermal plasma, but all of these methodologies have shortcomings for field application. Further combination of photocatalyst with nonthermal plasma into a hybrid reactor can induce interactions between plasma and photocatalyst to solve the bottlenecks and to enhance biogas reforming efficiency. In this study we developed a nonthermal plasma reactor to reform biogas into syngas, and prepared LaFeO3 (LFO), Ag-LaFeO3 (ALFO) and Ag-LaFeO3/TiO2 (ALFTO) to pack into plasma reactor individually to explore their influence on syngas generation rate. Results show that energy efficiency achieved with plasma reactor without photocatalyst and H2S is 14.5 mol/kWh, which is further increased to 20.2 mol/kWh as ALFTO photocatalyst is integrated to form the hybrid system. Introducing H2S reduces energy efficiency to 13.4 and 17.4 mol/kWh, respectively, and shorten the stable operation period of photocatalysis reactor. The effect of H2S can be reduced by adding BaTa0.3Nb0.7O3 (BTaNO) photocatalyst even though the energy efficiency is reduced. Synergy test results indicate that photocatalysts applied have catalytic and photocatalytic activities. In addition, the energy efficiency achieved with the hybrid reactor is higher than the summation of plasma-alone, catalysis and photocatalysis reactors, implying the existence of synergistic effects. Characterization of photocatalysts reveals good interactions between plasma and photocatalyst including plasma improves surface structure and photocatalyst enhances reaction rate and provides multi-reaction routes. Finally, TGA analysis result pointed out that addition of BTaNO reduces generation rate of sulfur-containing byproducts and further stabilize reforming system operation. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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