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Study On Start-up And Operational Parameters For Bio-hydrogen Production In UASB Reactor

Posted on:2012-10-12Degree:MasterType:Thesis
Country:ChinaCandidate:L WangFull Text:PDF
GTID:2131330335473443Subject:Environmental Science
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As a kind of clean, efficiency energy, hydrogen has gained more focus all around the world. And the new technology of biohydrogen production which is compatible with sustainable development strategies has the advantages of no fossil fuel energy consumption and low cost. Biohydrogen production technology is divided into anaerobic fermentative biohydrogen production and photosynthetic biohydrogen production. Compared with photosynthetic biohydrogen production, anaerobic fermentative biohydrogen production with high efficiency of hydrogen producing rate, steady production occurs at ambient temperatures and pressures, which is less energy intensive and more environmental friendly. Furthermore, fermentative biohydrogen production has the potential to the large-scale industrial production. However this technology hasn't improved into industrialization. This study chose brown sugar as substrate for biohydrogen production using an upflow anaerobic sludge bed (UASB) to investigate the probability of UASB reactor as the bioreactor for hydrogen production, and to prove the feasibility of biological hydrogen and the characteristics during the phases of start-up and steady operation.In this paper, brown sugar was used as the substrate to be the artificial wastewater, adding fertilized to provide nutrients nitrogen and phosphorus for microorganisms.COD concentration was kept at 4500 mg/L at the stage of start-up, and then adjusted to 6000 mg/L during the stage of stable operation for about 30 days. Temperature was controlled at about (35±1)℃; HRT was 8h. Finally, UASB reactor successfully achieved ethanol type fermentation.During the whole operation, ORP stably remained at the range of-380mV~-400mV. COD removal rate was above 28%. Although, pH value in feeding box varied a lot, the pH value in effluent was always stably maintained at the range of 4.5~5.0. Fermentative gas production kept significant increasing, the maximum value of which is 16.844 L/d while the hydrogen content is about 50% at the same time. Terminal liquid production was consisting of ethanol, acetic acid, butyric acid and propionic acid. As the expected aimed production, ethanol acid and acetic acid kept increasing, the proportion of which was large and stably maintaining at the range of 80~85%. Furthermore, the content of ethanol in terminal liquid production was significantly higher than acetic acid, propionic acid and butyric acid, which indicated that the system, in UASB reactor, successfully formed ethanol-type fermentation.Although this paper has proved that it is possible of the anaerobic UASB reactor for fermentative biohydrogen production, there is still a long way to go, for us, to improve the technology into industrialization. We should find out the most suitable factor, best structure of the UASB reactor, the best fermentative type and so on.
Keywords/Search Tags:Anaerobic fermentative biohydrogen production, UASB reactor, ethanol-type fermentation
PDF Full Text Request
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