| Summary: | 碩士 === 逢甲大學 === 化學工程學所 === 98 === This study was carried out on a continuously stirred anaerobic bioreactor (CSABR) for anaerobic fermentation of bio-hydrogen production with substrate of condensed molasses fermentation soluble (CMS). There are two kinds of bioreactor were used, one is call a suspension sludge bioreactor (SSB) which used the suspension seed sludge, the other one call an immobilized cell bioreactor (ICB) which used the immobilized cell which mixed the same seed sludge in ICB to be the source of the bacteria. It was found that the hydrogen production rate increased with the hydraulic retention time (HRT) decreased with substrate concentration was 40 g COD/L in SSB, and it obtained maximum hydrogen production rate of 14.04 ± 2.08 L/d/L at HRT 0.5 h (ca. 5.78 times of the value on HRT 4 h). While the maximum hydrogen production rate was 7.60 ± 1.05 L/d/L (ca. 1.23 times than HRT 4 h) at the same conditions in ICB. However, the hydrogen production rate has increased with increasing the substrate concentration from 40 g COD/L to 60 g COD/L when HRT was ranged from 4 to 2 h both in the SSB and ICB.
The pretreatment method of hydrocyclone was used to shorten the sedimentation time of the CMS substrate. The hydrogen production performance at a batch system was verified with supernatant and mixture substrates of CMS after sedimentation by hydrocyclone pretreatment. It was found that the hydrogen evolution using supernatant as substrate (322.75-328.89 mL) was increased 18% of the mixture substrate when SSB effluent as a seeding sludge. Moreover, the hydrogen evolution using supernatant as substrate (329.89-369.14 mL) was increased 12% of the mixture substrate when seeding sludge gained from ICB effluent.
Finally, the methods of bed pressure fluctuation analysis and dual electrical resistivity probe were used to investigate the hydrodynamic properties in the bioreactor. It was found that the dominant frequency and side frequency signals were unobvious from HRT 4 to 0.5h on the power spectrum diagram when using the CMS as the substrate in a biohydrogen production reactor. It seems belong to the dispersed bubble regime. However, it also can’t found any peaks on the power spectrum diagram at HRT 8 h. Therefore, the flow regime in the bioreactor could be defined as homogeneous system. The dual electrical resistivity probe could not effective detect the voltage when CMS used as the substrate in the biohydrogen production reactor. As a consequence, looking for a more reliable detector to gain the proper data of the hydrodynamics in the reactor is needed.
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