Influence of internal biogas production on hydrodynamic behavior of anaerobic fluidized-bed reactors.
Predictive models for describing the hydrodynamic behavior (bed-expansion and bed-pressure gradient) of a three-phase anaerobic fluidized bed reactor (AFBR) was developed according to wake theory together with more realistic dynamic bed-expansion experiments (with and without internal biogas production). A reliable correlation equation for the parameter k (mean volume ratio of wakes to bubbles) was also established, which is of help in estimating liquid hold up of fluidized beds. The experimental expansion ratio of three-phase fluidized beds (E(GLS)) was approximately 18% higher than that of two-phase fluidized beds (E(LS)); whereas the experimental bed-pressure gradient of the former [(-DeltaP/H)(GLS)] was approximately 9.3% lower than that of the latter [(-DeltaP/H)(LS)]. Both the experimental and modeling results indicated that a higher superficial gas velocity (u(g)) gave a higher E(GLS) and a higher E(GLS) to E(LS) ratio as well as a lower (-DeltaP/H)(GLS) and a lower (-DeltaP/H)(GLS) to (-DeltaP/H)(LS) ratio. As for the operation stability of the AFBR, the sensitivity of u(g) to expansion height (H(GLS)) and (-DeltaP/H)(GLS) is between the sensitivity of superficial liquid velocity and biofilm thickness. The model predictions of E(GLS), (-DeltaP)(GLS), and (-DeltaP/H)(GLS) agreed well the experimental measurements. Accordingly, the predictive models accounting for internal biogas production described fairly well the hydrodynamic behavior of the AFBR.
Wu
Chun-Sheng
CS
Department of Resource and Environment, Leader University, Tainan City, Taiwan 709, ROC. wujoe38@mail.leader.edu.tw
Huang
Ju-Sheng
JS
Chou
Hsin-Hsien
HH
D001421:Bacteria, Anaerobic; D019149:Bioreactors; D005544:Forecasting; D005740:Gases; D008962:Models, Theoretical; D011312:Pressure; D012680:Sensitivity and Specificity; D014872:Water Movements; D018508:Water Purification
D005740:Gases