2026-09-19T08:30:05Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/1042632022-01-13T07:54:05Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Alexander H. Slocum.
O'Brien, Megan Lynn
Massachusetts Institute of Technology. Department of Mechanical Engineering.
Massachusetts Institute of Technology. Department of Mechanical Engineering
2016-09-13T19:18:50Z
2016-09-13T19:18:50Z
2016
2016
http://hdl.handle.net/1721.1/104263
958160035
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 143-149).
Significant volumes of biomass waste are generated each year as a result of agricultural practices in India. Despite the negative environmental impacts, in-situ incineration of crop residues is common practice for disposal of this waste. Transportation of raw biomass accounts for a significant portion of the cost of biomass conversion processes due to its low energy density and high bulk volume. The use of raw biomass also reduces the overall efficiency of thermochemical conversion processes due to high moisture content, over-oxidation of the fuel resulting from high oxygen content, and the relatively high oxygen to carbon ratio. There has been much recent interest in improving the properties of biomass prior to gasification and pyrolysis through densification, drying, and mild thermochemical treatments. One approach is a process known as torrefaction, which is a mild pyrolysis process that is shown to produce an energy-dense fuel with improved transport, storage, and feedstock characteristics. Particularly in the Indian context, there is a need for the development of a small-scale system which can densify and upgrade the properties of agricultural residues after harvest. This thesis presents the design and preliminary testing of a lab-scale moving-bed torrefaction reactor. Key learnings from the assembly and testing of this machine are identified and recommendations for improvement are made. A rudimentary model evaluating the heat transfer in packed bed of biomass is developed to provide a framework for analyzing future reactor designs. The functional requirements of a labscale screw conveyor torrefaction reactor are developed based on this analysis and a preliminary reactor architecture is proposed. Multiple studies are recommended to improve the reliability of the heat transfer model. Recommendations are made for future design iterations of the lab-scale screw conveyor torrefaction reactor.
by Megan Lynn O'Brien.
S.M.
150 pages
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
http://dspace.mit.edu/handle/1721.1/7582
Mechanical Engineering.
Design of a mobile torrefaction reactor for in-situ conversion of agricultural waste to solid biofuel
Thesis
application/pdf
Publication
unknown
unknown
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<Abstract>Significant volumes of biomass waste are generated each year as a result of agricultural practices in India. Despite the negative environmental impacts, in-situ incineration of crop residues is common practice for disposal of this waste. Transportation of raw biomass accounts for a significant portion of the cost of biomass conversion processes due to its low energy density and high bulk volume. The use of raw biomass also reduces the overall efficiency of thermochemical conversion processes due to high moisture content, over-oxidation of the fuel resulting from high oxygen content, and the relatively high oxygen to carbon ratio. There has been much recent interest in improving the properties of biomass prior to gasification and pyrolysis through densification, drying, and mild thermochemical treatments. One approach is a process known as torrefaction, which is a mild pyrolysis process that is shown to produce an energy-dense fuel with improved transport, storage, and feedstock characteristics. Particularly in the Indian context, there is a need for the development of a small-scale system which can densify and upgrade the properties of agricultural residues after harvest. This thesis presents the design and preliminary testing of a lab-scale moving-bed torrefaction reactor. Key learnings from the assembly and testing of this machine are identified and recommendations for improvement are made. A rudimentary model evaluating the heat transfer in packed bed of biomass is developed to provide a framework for analyzing future reactor designs. The functional requirements of a labscale screw conveyor torrefaction reactor are developed based on this analysis and a preliminary reactor architecture is proposed. Multiple studies are recommended to improve the reliability of the heat transfer model. Recommendations are made for future design iterations of the lab-scale screw conveyor torrefaction reactor.</Abstract>
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