Torrefied Biomass Gasification with Carbon Dioxide in a Fluidized Bed
| Autor: | Yu-Shan Shih, 施侑杉 |
|---|---|
| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 Torrefaction is a thermochemical pre-treatment technology at lower temperature under atmospheric conditions and in the absence of oxygen to convert the raw biomass into torrefied biomass with the higher heating value and better storage property. Gasification is a thermochemical process to convert biomass into the syngas fuel by partial oxidation at elevated temperature. However, removal of a large amount of volatiles after torrefaction, torrefied biomass gasification with air cannot enhance the syngas production and quality. Therefore, applying the Boudouard reaction, gasification of torrefied biomass with CO2 at higher temperature could improve the syngas quality. Therefore, in this study, gasification of the raw biomass and the biomass torrefied at 250 and 350oC, respectively with CO2 was carried out in a 30 kWth bubbling fluidized bed gasifier to compare with the results of gasification of torrefied biomass with air. Also, the effects of gasification of torrefied biomass with CO2 on the syngas composition were investigated. The results shows that carbon dioxide gasification at a higher temperature above 800oC can enhance CO concentration up to 28.8% compared with the air-blown gasification process, due to the Boudouard reaction with the higher carbon content of the torrefied biomass. In addition, because the CnHm content from CO2 gasification is higher than that from air-blown gasification, the heating value of the syngas is also higher from CO2 gasification. Also, CO2 gasification can decrease the tar content down to 0.25 g / Nm3. Therefore, gasification of torrefied biomass with CO2 can enhance syngas heating value and reduce the tar content to improve the disadvantages of air--blown gasification. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|