By the integration of dark and photo fermentative hydrogen production processes, higher yields of hydrogen can be obtained from biomass. In the first step, biomass is utilized for hydrogen production by dark fermentation and in the second step, the effluent of dark fermentation is further utilized for hydrogen production by photofermentation using photosynthetic purple non-sulfur bacteria. The purpose of this study was to develop a solar pilot scale tubular photobioreactor (PBR) for continuous photo fermentative hydrogen production from the effluent of dark fermentation.
This study demonstrated the implementation of the solar pilot tubular PBR for this new technology for the first time and successful continuous operations were performed in different seasons. Two different strains of Rhodobacter capsulatus were used for the operations. It was showed that even in winter, pure hydrogen could be produced in the pilot PBR with an average productivity of 0.3 mol H2/m3.h, when circulation of the PBR was continuous. Productivity obtained by the mutant strain was 0.2 mol H2/m3.h with periodical circulation. The integration between dark and photo fermentation was proven at pilot scales by using real dark fermenter effluents of molasses and thick juice. DFE of thick juice yielded a maximum productivity of 0.27 mol H2/m3.h whereas the maximum productivity obtained from DFE of molasses was 0.12 mol H2/m3.h. The most important factor affecting productivity is found to be the total received light energy and a yield factor (mmol H2/g dry cell weight) was correlated with total received light energy. Acetic acid consumption rates were found to be first order for daytime and zero order for nights. Furthermore acetic acid utilization for different metabolic pathways were estimated and by-product, poly- &beta / - hydroxybutyrate, specific rates of product formation were determined.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12612955/index.pdf |
| Date | 01 February 2011 |
| Creators | Boran, Efe |
| Contributors | Eroglu, Inci |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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