MADMEC III:
Making and Designing Materials Engineering Contest
"Materials Solutions for Alternative Energy"

Team Name: Team Biomethane

Team Members:
Ethan Bates, '10
Richard Bates, '10
Jonathan Estrada, DMSE '11
Michael Gerhardt, DMSE '12

Abstract:
Biogas has seen renewed interest as a result of rising concerns over climate change [1] [2], excessive dependence on fossil fuels, and the need to address developmental and health concerns. [3].

The limited ability to compress and store biogas for transportation, sale, or future use remains a major issue. Biogas usage is restricted to sites in proximity of biogas creation. This reduces the economic viability of highly beneficial biogas appliances such as biogas powered stoves, lamps, heaters, and engines. Additionally, the presence of other gases like hydrogen sulfide, carbon dioxide, and water vapor all reduce its usability and potential for compression/storage. Thus the need arises to develop an affordable integrated gas purification (known as scrubbing) and compression system. We have developed a proof of concept pump and water scrubbing system that is capable of lowering CO2 concentrations down to 5.5% (from 40%). It is easily constructed using cheap materials (less than $20), such as a bike pump, inner tube valves, soda bottles and hosing. The (liquid and gas) pump has the ability to create high pressures (10 bar or 150 psi) and medium vacuums simultaneously, giving it many agricultural applications beyond biogas pressurization. We?re beginning investigation of more robust, efficient, and safe materials for a pressure vessel and pump. We will continue investigating polyethylene terepthalate (PET) and butyl rubber, while looking at polycarbonate and acrylonitrile butadiene styrene (ABS) as materials for an affordable (possibly transportable) pressure vessel. For the pump, we hope to either improve the efficiency of the manual pumping method, or develop or modify an electric gas pump.

[1] UNESCAP. “Recent Developments in Biogas Technology for Poverty Reduction and
Sustainable Development” United Nations. 2007

[2] Yu, Liu et al.“Popularizing household-scale biogas digesters for rural sustainable
energy development and greenhouse gas mitigation” Graduate University of Chinese Academy
of Sciences. Renewable Energy 33 (2008) 2027–2035

[3] ISAT. “Biogas Digest Volume II: Biogas Application and Product Development”
Information and Advisory Service on Appropriate Technology.
http://www.gtz.de/de/dokumente/en-biogas-volume2.pdf

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