A draft tube fluidized bed reactor (DTFBR) containing immobilized cell particles was designed to produce H2 continuously. A synthetic polymer (silicone gel; SC) was used as the primary material to immobilize acclimated anaerobic sludge for H2 production in DTFBR with a working volume of 8 L. The DTFBR system was operated at a hydraulic retention time (HRT) of 2.2-8.9 h and an influent sucrose concentration (Cs) of 5-40 g COD/l. The results show that in general decreasing HRT or increasing sucrose concentration led to a marked increase in the volumetric H2 production rate (vH2), but a gradual decrease in the H2 yield (YH2). The best vH2 (2.27 ± 0.13 l / h / l) occurred at Cs = 40 g COD/l and HRT = 2.2 h, whereas the highest YH2 (4.98 ± 0.18 mol H2/mol sucrose) was obtained at Cs = 40 g COD/l and HRT = 8.9 h. The correlation between the production rate and the organic loading rate (OLR) can be satisfactorily described by Monod-type models. There was no universal trend of the dependence between the H2 yield and OLR. The H2 content in the biogas was stably maintained at over 40%. The major soluble products were butyric acid and acetic acid, as they accounted for 62-73% and 16-22% of total soluble microbial products (SMPs), respectively. The H2-producing performance in the DTFBR system can be stably maintained and reproducible in long-term operations, while unstable operations can be quickly recovered via proper thermal treatment at 70-80 °C.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Condensed Matter Physics
- Energy Engineering and Power Technology