Home About us Contact
|
Home About us Contact | ||
|
|
||
Increasing Flow Rate (increasing + flow_rate)
Selected AbstractsNear Wall Studies of Pulp Suspension Flow Using LDATHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2006A. Johan Pettersson Abstract A detailed study of the flow behaviour in the near wall region of pulp suspensions up to 4.7% have been performed using Laser Doppler Anemometry (LDA) in pipe flow. Axial mean velocity profiles show a distinct plug flow and an increase of the plug region as the flow rate decreases and fibre concentration increases. An attempt is made to relate the LDA data-rate to fibre concentration, which indicates a dilution region at 1-2 mm from the wall that is larger than the annulus region. The dilution region increases with increasing flow rate, decreasing concentration and when using longer pulp fibres. On a réalisé une étude détaillée du comportement d'un écoulement dans la région proche de la paroi de suspensions de pâte jusqu'à 4,7 %, en utilisant l'anémométrie laser Doppler (LDA) dans une conduite. Les profils de vitesse axiale moyens montrent un écoulement piston distinct et une augmentation de la région piston lorsque le débit diminue et la concentration de fibres augmente. Une tentative est faite pour relier les données de vitesse LDA à la concentration de fibres, qui indique une région de dilution à 1-2 mm de la paroi plus grande que l'espace annulaire. La région de dilution augmente avec l'augmentation du débit, la diminution de la concentration et l'utilisation de fibres de pâtes plus longues. [source] Biosorption of heavy metal using brown seaweed in a regenerable continuous columnASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2008N. Rajamohan Abstract This paper deals with the experimental investigation on removal of cadmium [Cd(II)] ions from an aqueous solution using a marine alga, Sargassum tenerrimum, in a fixed-bed column. The effects of the inlet flow rate and the sorbent bed height on the biosorption of Cd(II) ions were studied. The dynamics of column biosorption was modeled by the bed depth service time (BDST) model and the Thomas model. The BDST model was used to study the dynamic sorption behavior at different bed heights, whereas the Thomas model was used to fit the column biosorption data at different flow rates. The uptake capacity and the breakthrough time increase with an increase in the bed height. The sorption capacities of the bed per unit volume and the rate constant Ka were found to be 3819.42 mg/l and 0.0353 mg/h respectively. In flow rate experiments, the results confirmed that the metal uptake capacity and the metal removal efficiency of S. tenerrimum decreased with increasing flow rate. The Thomas model was used to fit the column biosorption data at different flow rates and model constants were evaluated. After five sorption,desorption cycles, the selected marine alga exhibited a high cadmium uptake of 63.43 mg/g. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Hydrophobic interaction chromatography in dual salt system increases protein binding capacityBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009Anna M. Senczuk Abstract Hydrophobic interaction chromatography (HIC) uses weakly hydrophobic resins and requires a salting-out salt to promote protein,resin interaction. The salting-out effects increase with protein and salt concentration. Dynamic binding capacity (DBC) is dependent on the binding constant, as well as on the flow characteristics during sample loading. DBC increases with the salt concentration but decreases with increasing flow rate. Dynamic and operational binding capacity have a major raw material cost/processing time impact on commercial scale production of monoclonal antibodies. In order to maximize DBC the highest salt concentration without causing precipitation is used. We report here a novel method to maintain protein solubility while increasing the DBC by using a combination of two salting-out salts (referred to as dual salt). In a series of experiments, we explored the dynamic capacity of a HIC resin (TosoBioscience Butyl 650M) with combinations of salts. Using a model antibody, we developed a system allowing us to increase the dynamic capacity up to twofold using the dual salt system over traditional, single salt system. We also investigated the application of this novel approach to several other proteins and salt combinations, and noted a similar protein solubility and DBC increase. The observed increase in DBC in the dual salt system was maintained at different linear flow rates and did not impact selectivity. Biotechnol. Bioeng. 2009;103: 930,935. © 2009 Wiley Periodicals, Inc. [source] External modulation of HT-1080 human fibrosarcoma cells improves urokinase productionBIOTECHNOLOGY PROGRESS, Issue 6 2008Shilpa S. Khaparde Abstract Urokinase was produced in a hollow fiber reactor using HT-1080 human fibrosarcoma cells. External modulation comprised replenishing of the medium in the extracapillary space, reducing the serum concentration in the extracapillary space from 10% to 2% and increasing flow rate of the circulating medium in the intracapillary space from 20 to 80 mL/min, each according to a specific protocol. More than sixfold increase was observed in the cumulative urokinase production for two and three medium replenishing modulations of the extracapillary space. After 15 days of continuous operation, the highest cumulative urokinase obtained was 1.63 × 106 PU/mL. SDS-PAGE and zymogram study established that the urokinase obtained was in the high molecular weight range of 54 kDa. The effect of external modulation on cumulative urokinase production was visualized as trajectories with respect to the ratio of lactic acid production rate (LPR) to the glucose uptake rate (GUR). The collective external modulation data showed two separate physiological regions in the cumulative urokinase vs. LPR/GUR plane. The HT-1080 cells exhibited two distinct morphologies in these regions that may be related to acidosis and metastasis. These regions also correspond to low and high urokinase productivity. [source] Oxidation of Benzene to Maleic Anhydride in a Fluidized Bed ReactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 12 2007C. Uraz Abstract In this project, the selective oxidation of benzene to maleic anhydride (MAN) was studied. Gas phase catalytic oxidation of benzene was carried out in a laboratory scale fluidized bed reactor on six different types of catalysts, which have different compositions. Effects of temperature, flow rates of benzene and air and catalyst type on the reaction selectivity were investigated at atmospheric pressure. The experiments were performed over a temperature range of 325 to 400,°C, a space-time (W/FA0) range from 11.28,×,105 to 31.9,×,105 g,s,mol,1, and benzene/air mole ratio changes between 0.0109 and 0.0477. It was seen that conversion of benzene to MAN increased with increasing temperature for the catalysts supported by silica gel, aluminum oxide and titanium oxide. From the results it was found that conversion increased with increasing flow rate of air. When the comparison of the catalysts were made, it could be said that catalysts supported by silica gel showed higher MAN conversions. So it can be concluded that catalysts supported by silica gel were more suitable catalysts for benzene oxidation to MAN in a fluidized bed reactor. [source] | |||||||||||||