Biomass reforming processes in hydrothermal media

While hydrothermal technologies offer distinct advantages in being able to process a wide variety of biomass feedstocks, the composition of the feedstock will have a large effect on the processing employed. This thesis characterizes the role of two major components of biomass, salts and proteins, that if dealt with intelligently can create valuable byproducts, but if dealt with inefficiently can cause processes to fail or run sub-optimally. In supercritical-water, most ionic species exhibit only sparing solubility. Thus, in the supercritical-water gasification of biomass, a supercritical-water reverse-flow vessel (RFV) may be employed to precipitate the salts from the biomass before the biomass is brought into contact with catalysts. However, these vessels are subject to blockage, and flow characterization within the vessels has largely been unknown. Therefore, the technique of neutron radiography is introduced to the supercritical-water processing field in order to characterize the behavior within these RFVs. This allows for non-invasive, in situ, real-time measurements of precipitation phenomena within thick-walled vessels. Two methods that provide complimentary information were developed to observe the precipitation behavior of salts from supercritical water. In the first method ("normalphase" radiography), the salts have a lower attenuation coefficient than the continuous 1H2O phase. This allowed for the visualization of major blockages, buildups of salts at the walls, and flow pattern changes. By using the strongly attenuating 1H2O form of water, fluid density changes resulting from flow pattern changes were also apparent.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Peterson, Andrew A

Advisor dc:contributor.advisor

• Jefferson W. Tester.

• Chemical Engineering.

Statement dc:rights

• 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.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/51678

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/51678