An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization
The goal of this work is to understand the gasification process for Miscanthus briquettes in a double-stage downdraft gasifier, and the impact of different Equivalence Ratios (ER) on syngas, biochar, and tar characteristics. The optimal ER was found to be 0.35, which yielded a syngas maximum heating...
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MDPI AG
2018-11-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/11/11/3225 |
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| author | Tejasvi Sharma Diego M. Yepes Maya Francisco Regis M. Nascimento Yunye Shi Albert Ratner Electo E. Silva Lora Lourival Jorge Mendes Neto Jose Carlos Escobar Palacios Rubenildo Vieira Andrade |
| author_facet | Tejasvi Sharma Diego M. Yepes Maya Francisco Regis M. Nascimento Yunye Shi Albert Ratner Electo E. Silva Lora Lourival Jorge Mendes Neto Jose Carlos Escobar Palacios Rubenildo Vieira Andrade |
| author_sort | Tejasvi Sharma |
| collection | DOAJ |
| description | The goal of this work is to understand the gasification process for Miscanthus briquettes in a double-stage downdraft gasifier, and the impact of different Equivalence Ratios (ER) on syngas, biochar, and tar characteristics. The optimal ER was found to be 0.35, which yielded a syngas maximum heating value of 5.5 MJ/Nm<sup>3</sup> with a syngas composition of 20.29% CO, 18.68% H<sub>2</sub>, and 0.86% CH<sub>4</sub>. To better understand the observed behavior, an equilibrium reaction model was created and validated using the experimental data. The model showed that the heating value decreased with increasing ER, and that hydrogen production peaked at ER = 0.37, while methane (CH<sub>4</sub>) became negligible above ER = 0.42. Tar and particle content in the gas produced at a certain temperature can now be predicted. To assess the biochar characteristics, surface structure image analysis and a surface area porosity analysis were carried out. Employing images from a scanning electron microscope (SEM), the biochar cell bonds and pore structures were examined and analyzed. By using the Brunauer-Emmett-Teller (BET) analysis of the surface porosity, the surface area to be 186.06 m<sup>2</sup>/g and the micro pore volume was calculated to be 0.07 m<sup>3</sup>/g. The final aspect of the analysis involved an evaluation of tar production. Combining current and prior data showed a logarithmic relationship between the amount of tar produced and the gasifier bed temperature, where the amount of tar produced decreased with increasing bed temperature. This results in very low tar levels, which is one of the known advantages for a double-stage downdraft gasifier over a single-stage system. |
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| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-14T00:34:08Z |
| publishDate | 2018-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-8958d9df6e114c85abbc7d889c963b5d2022-12-22T02:22:26ZengMDPI AGEnergies1996-10732018-11-011111322510.3390/en11113225en11113225An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar CharacterizationTejasvi Sharma0Diego M. Yepes Maya1Francisco Regis M. Nascimento2Yunye Shi3Albert Ratner4Electo E. Silva Lora5Lourival Jorge Mendes Neto6Jose Carlos Escobar Palacios7Rubenildo Vieira Andrade8Department of Mechanical Engineering, University of Iowa, Iowa, IA 52246, USAMechanical Engineering Institute, Federal University of Itajubá (UNIFEI), Itajuba, MG 37500-103, BrazilMechanical Engineering Institute, Federal University of Itajubá (UNIFEI), Itajuba, MG 37500-103, BrazilDepartment of Engineering and Physics, St. Ambrose University, Davenport, IA 52803, USADepartment of Mechanical Engineering, University of Iowa, Iowa, IA 52246, USAMechanical Engineering Institute, Federal University of Itajubá (UNIFEI), Itajuba, MG 37500-103, BrazilMechanical Engineering Institute, Federal University of Itajubá (UNIFEI), Itajuba, MG 37500-103, BrazilMechanical Engineering Institute, Federal University of Itajubá (UNIFEI), Itajuba, MG 37500-103, BrazilMechanical Engineering Institute, Federal University of Itajubá (UNIFEI), Itajuba, MG 37500-103, BrazilThe goal of this work is to understand the gasification process for Miscanthus briquettes in a double-stage downdraft gasifier, and the impact of different Equivalence Ratios (ER) on syngas, biochar, and tar characteristics. The optimal ER was found to be 0.35, which yielded a syngas maximum heating value of 5.5 MJ/Nm<sup>3</sup> with a syngas composition of 20.29% CO, 18.68% H<sub>2</sub>, and 0.86% CH<sub>4</sub>. To better understand the observed behavior, an equilibrium reaction model was created and validated using the experimental data. The model showed that the heating value decreased with increasing ER, and that hydrogen production peaked at ER = 0.37, while methane (CH<sub>4</sub>) became negligible above ER = 0.42. Tar and particle content in the gas produced at a certain temperature can now be predicted. To assess the biochar characteristics, surface structure image analysis and a surface area porosity analysis were carried out. Employing images from a scanning electron microscope (SEM), the biochar cell bonds and pore structures were examined and analyzed. By using the Brunauer-Emmett-Teller (BET) analysis of the surface porosity, the surface area to be 186.06 m<sup>2</sup>/g and the micro pore volume was calculated to be 0.07 m<sup>3</sup>/g. The final aspect of the analysis involved an evaluation of tar production. Combining current and prior data showed a logarithmic relationship between the amount of tar produced and the gasifier bed temperature, where the amount of tar produced decreased with increasing bed temperature. This results in very low tar levels, which is one of the known advantages for a double-stage downdraft gasifier over a single-stage system.https://www.mdpi.com/1996-1073/11/11/3225biomassgasificationbiochartardowndraft reactorproducer gas |
| spellingShingle | Tejasvi Sharma Diego M. Yepes Maya Francisco Regis M. Nascimento Yunye Shi Albert Ratner Electo E. Silva Lora Lourival Jorge Mendes Neto Jose Carlos Escobar Palacios Rubenildo Vieira Andrade An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization Energies biomass gasification biochar tar downdraft reactor producer gas |
| title | An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization |
| title_full | An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization |
| title_fullStr | An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization |
| title_full_unstemmed | An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization |
| title_short | An Experimental and Theoretical Study of the Gasification of Miscanthus Briquettes in a Double-Stage Downdraft Gasifier: Syngas, Tar, and Biochar Characterization |
| title_sort | experimental and theoretical study of the gasification of miscanthus briquettes in a double stage downdraft gasifier syngas tar and biochar characterization |
| topic | biomass gasification biochar tar downdraft reactor producer gas |
| url | https://www.mdpi.com/1996-1073/11/11/3225 |
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