Hydrodynamic characteristics of reversed flow jet loop reactor as a gas—liquid—solid contactor
01 Jan 1991-Chemical Engineering Science (Pergamon)-Vol. 46, Iss: 12, pp 3293-3296
About: This article is published in Chemical Engineering Science.The article was published on 1991-01-01. It has received 19 citations till now. The article focuses on the topics: Jet (fluid) & Contactor.
TL;DR: In this paper, the authors investigated the use of a jet loop membrane bioreactor combined with a membrane process to treat wastewater containing high organic matter and found that the membrane process has distinctive advantages such as the ability to treat high strength wastewater, low area requirements and easy operation.
TL;DR: Developing a jet loop reactor (JLR) with circulation of a surfactant solution to lower the concentration of VOCs, especially hydrophobic V OCs is believed to ensure the stable operation of the biofilter even with the unexpected increase in the VOC concentrations.
TL;DR: In this article, a modified reversed flow jet loop reactor with the liquid outlet at the top of the reactor was used to determine the gas holdup and overall volumetric mass transfer coefficient in the air-water system.
Abstract: Experiments were conducted in a modified reversed flow jet loop reactor having the liquid outlet at the top of the reactor to determine the gas holdup and overall volumetric mass transfer coefficient in the air-water system. The influence of gas and liquid flow rates, and the draft tube to reactor diameter ratio were studied. It was observed that both gas holdup and volumetric mass transfer coefficient increased with increased gas and liquid flow rates and were found to be significantly higher in the modified reactor compared to the conventional one. The optimum draft tube to reactor diameter ratio was found to be in the range of 0.4 to 0.5. Empirical correlations are presented to predict gas holdup and overall volumetric mass transfer coefficient in terms of operational and geometrical variables. Des experiences ont ete menees dans un reacteur a boucle a jet d'ecoulement renverse modifie, dans lequel la sortie liquide est situee au sommet du reacteur, afin de determiner la retention de gaz et le coefficient de transfert de matiere volumetrique global dans le systeme air-eau. L'influence des debits liquides et gazeux et le rapport entre le tube d'aspiration et le diametre du reacteur ont egalement ete etudies. On a observe que la retention de gaz et le coefficient de transfert de matiere volumetrique augmentaient avec l'augmentation des debits liquides et gazeux et que, par ailleurs, ils etaient considerablement plus eleves dans le reacteur modifie que dans le reacteur conventionnel. On a trouve que le rapport optimal entre le tube d'aspiration et le diametre du reacteur se situait dans la gamme de 0,4 a 0,5. Des correlations empiriques sont presentees pour predire la retention de gaz et le coefficient de transfert de matiere volumetrique global en termes de variables geometriques et de fonctionnement.
TL;DR: In this paper, experiments were performed to obtain the overall volumetric mass transfer coefficient, K L a in the modified gas-liquid-solid reversed flow jet loop this paper.
TL;DR: In this article, a modified drift-flux model was developed for correlating the S-shape relationship of overall gas holdup and gas velocity, and experiments showed that the gas-liquid co-injection mode results in larger gas hold up and liquid circulation velocity than those of the gas jet alone mode.
Abstract: Hydrodynamics in an up flow jet-loop reactor (JLR) is experimentally investigated. The overall gas holdup, radial and axial distributions of local gas holdup and liquid velocity are presented. A modified drift-flux model was developed for correlating the “S-shape” relationship of overall gas holdup and gas velocity. Experiments show that the gas–liquid co-injection mode results in larger gas holdup and liquid circulation velocity than those of the gas jet alone mode. Liquid velocity distribution is more prone to reach the fully developed regime than the gas holdup, and the gas–liquid co-injection promotes the flow development. Comparison of JLR with the conventional bubble column (BC) and airlift reactor (ALR) shows that the JLR has a largest liquid circulation velocity, which is mostly beneficial to liquid mixing and solid suspension.
TL;DR: In this paper, the authors investigated the hydrodynamic properties of a gas-liquid-solid spouted bed with a draft tube and found that the friction factor accounting for the friction loss in the bed varies linearly on a logarithmic scale with the Reynolds number defined based on the apparent liquid circulation rate.
TL;DR: In this paper, the critical solid holdup in the draft tube slurry column was found to be much greater than that in the conventional bubble column, and an empirical correlation was developed to account for the critical holdup behavior in the column.
Abstract: Fundamental characteristics of hydrodynamics and mass transfer have been measured in an air lift slurry reactor with a draft tube. The solid suspension capacity, i.e., the critical solid holdup, the gas holdup and the volumetric gas-liquid mass transfer coefficient were measured in the two draft tube columns of 0.1485 and 0.10 m in diameter. Four activated carbon beads ranging in size from 0.25 to 2.19 mm in average diameter were utilized as suspended solids in the experiments. The critical solid holdup in the draft tube slurry column is found to be much greater than that in the conventional bubble column. An empirical correlation is developed to account for the critical solid holdup behavior in the draft tube column. The gas holdup in the draft tube column agrees well with that in the bubble column. The overall gas-liquid mass transfer coefficient, k1awas measured by the oxygen probe method. The effect of solid holdup on k1a is found to be negligible in the present system. The empirical equation is devel...
01 Jan 1985
TL;DR: The fonctionnement de cet absorbeur depend principalement du rapport entre les diametres du tube d'aspiration and du reacteur as mentioned in this paper.
Abstract: Absorbeur a tube d'aspiration, avec entree du gaz au sommet du reacteur par l'intermediaire d'un tube place au centre de l'ajustage du liquide. Le fonctionnement de cet absorbeur depend principalement du rapport entre les diametres du tube d'aspiration et du reacteur. Mesure des coefficients de transfert de matiere volumetrique par la methode dynamique d'absorption de l'oxygene de l'air
TL;DR: In this article, the effects of solids and liquid surface tension on the gas holdup and the mass transfer parameters a and kL a were measured in two and three phase downflow bubble columns.
Abstract: Gas holdup, effective interfacial area and volumetric mass transfer coefficient were measured in two and three phase downflow bubble columns. The mass transfer data were obtained using the chemical method of sulfite oxidation, and the gas holdup was measured using the hydrostatic technique. Glass beads and Triton 114 were used to study the effects of solids and liquid surface tension on the gas holdup and the mass transfer parameters a and kL a . The gas holdup in three phase systems was measured for non-wettable (glass bead) and wettable (coal and shale particles) solids. The mass transfer data obtained in the downflow bubble column were compared with the values published for upflow bubble columns. The results indicate that in the range of superficial gas velocities (0.002-0.025) m/s investigated, the values of the mass transfer coefficient were of the same order of magnitude as those observed in upflow systems, but the values of interfacial area were at least two fold greater. Also, the results...