Effect of Wine Properties and Operating Mode upon Mass Transfer in Micro-Oxygenation

2010 ◽  
Vol 6 (6) ◽  
Author(s):  
Igor Chiciuc ◽  
Vincent Farines ◽  
Martine Mietton-Peuchot ◽  
Audrey Devatine
Keyword(s):  
Mass Transfer ◽  
Oxygen Transfer ◽  
Gas Flow ◽  
Operating Mode ◽  
Geometrical Aspect ◽  
Gaseous Oxygen ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Anti Oxidant ◽  
Viscosity Enhancement

All along wine-making and during its ageing, oxygen plays an important role for the evolution of the wine. Solubilization of oxygen into musts or wines occurs when gaseous oxygen is brought into contact with the liquid. In this work, the specific technique of wine micro-oxygenation is addressed through the evaluation of transfer capacity for oxygen solubilization. This was done considering the parameters likely to influence the saturation concentration of dissolved oxygen and the conventional volumetric mass transfer coefficient kLa, which quantifies the efficiency of the oxygen transfer. The study has shown that the sugar concentration in the must induces a viscosity enhancement which leads to a significant decrease of the kLa value. Surprisingly, it was also observed that a very low quantity of ethanol in the liquid phase (0.05 percent volume) strongly favours the oxygen transfer. Conversely, the presence of dissolved carbon dioxide in the wine, which desorbs and dilutes the oxygen in the micro-bubbles, dramatically decreases the transfer of oxygen. The presence of anti-oxidant compounds (SO2) or oxygen consumer compounds (polyphenols) was shown to have no effect upon the efficiency of oxygen transfer. Operating parameters such as gas flow rate or geometrical aspect of the tank have also been considered.

Impact of Dursban and Abate on Microbial Numbers and Some Chemical Properties of Standing Ponds

1975 ◽  
Vol 10 (1) ◽  
pp. 33-41 ◽  
Author(s):  
J. Butcher ◽  
M. Boyer ◽  
CD. Fowle
Keyword(s):  
Carbon Dioxide ◽  
Active Ingredient ◽  
Algal Blooms ◽  
Chemical Properties ◽  
Total Carbon ◽  
Dissolved Carbon ◽  
Photosynthetic Productivity ◽  
Dissolved Carbon Dioxide ◽  
Microbial Numbers

Abstract Eleven small ponds, lined with polyethylene, were used to assess the consequences of applications of *DursbanR at 0.004, 0.030, 0.100 and 1.000 ppm and AbateR at 0.025 and 0.100 ppm active ingredient. The treated ponds showed a more pronounced long-term increase in pH and dissolved oxygen and decreasing total and dissolved carbon dioxide in comparison with untreated ponds. Algal blooms were of longer duration in treated ponds than in controls. Total photosynthetic productivity was higher in treated ponds but bacterial numbers did not change significantly. Photosynthetic productivity was estimated by following the changes in total carbon dioxide.

Strategies and adaptations to aquatic life at high altitude

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Environmental Conditions ◽  
Low Temperatures ◽  
Cold Adaptation ◽  
Inorganic Carbon ◽  
Direct Result ◽  
Aquatic Life ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Regulatory Capacity

Chapter 5 is focused on how organisms cope with the environmental conditions that are a direct result of high altitude. Organisms reveal a number of fascinating ways of dealing with a life at high altitude; for example, avoidance and pigmentation as protection against damaging high levels of ultraviolet radiation, accumulation of antifreeze proteins, and metabolic cold adaptation among species encountering low temperatures with the risk of freezing, oxy-regulatory capacity in animals due to low availability of oxygen, and root uptake from the sediment of inorganic carbon by plants living in waters poor in dissolved carbon dioxide. These and more adaptations are carefully described through a number of examples from famous flagship species in addition to the less well-known ones. Harsh environmental conditions work as an environmental filter that only allows the well-adapted species to slip through to colonize high altitude waters.

scholarly journals Two-Phase Flow Mass Transfer Analysis of Airlift Pump for Aquaculture Applications

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 226
Author(s):  
Rashal Abed ◽  
Mohamed M. Hussein ◽  
Wael H. Ahmed ◽  
Sherif Abdou
Keyword(s):  
Mass Transfer ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Two Phase Flow ◽  
Oxygen Transfer Rate ◽  
Flow Patterns ◽  
Oxygen Mass Transfer ◽  
Phase Flow ◽  
Two Phase ◽  
Airlift Pump

Airlift pumps can be used in the aquaculture industry to provide aeration while concurrently moving water utilizing the dynamics of two-phase flow in the pump riser. The oxygen mass transfer that occurs from the injected compressed air to the water in the aquaculture systems can be experimentally investigated to determine the pump aeration capabilities. The objective of this study is to evaluate the effects of various airflow rates as well as the injection methods on the oxygen transfer rate within a dual injector airlift pump system. Experiments were conducted using an airlift pump connected to a vertical pump riser within a recirculating system. Both two-phase flow patterns and the void fraction measurements were used to evaluate the dissolved oxygen mass transfer mechanism through the airlift pump. A dissolved oxygen (DO) sensor was used to determine the DO levels within the airlift pumping system at different operating conditions required by the pump. Flow visualization imaging and particle image velocimetry (PIV) measurements were performed in order to better understand the effects of the two-phase flow patterns on the aeration performance. It was found that the radial injection method reached the saturation point faster at lower airflow rates, whereas the axial method performed better as the airflow rates were increased. The standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) were calculated and were found to strongly depend on the injection method as well as the two-phase flow patterns in the pump riser.

Mass Transfer Coefficients during Steel Decarburization in a RH Degasser

2008 ◽  
Vol 273-276 ◽  
pp. 679-684
Author(s):  
Roberto Parreiras Tavares ◽  
André Afonso Nascimento ◽  
Henrique Loures Vale Pujatti
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Vacuum Chamber ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Flow Rate ◽  
Rh Process ◽  
Kinetics Of

The RH process is a secondary refining process that can simultaneously attain significant levels of removal of interstitial elements, such as carbon, nitrogen and hydrogen, from liquid steel. In the RH process, the decarburization rate plays a very important role in determining the productivity of the equipment. The kinetics of this reaction is controlled by mass transfer in the liquid phase. In the present work, a physical model of a RH degasser has been built and used in the study of the kinetics of decarburization. The effects of the gas flow rate and of the configurations of the nozzles used in the injection of the gas have been analyzed. The decarburization reaction of liquid steel was simulated using a reaction involving CO2 and caustic solutions. The concentration of CO2 in the solution was evaluated using pH measurements. Based on the experimental results, it was possible to estimate the reaction rate constant. A volumetric mass transfer coefficient was then calculated based on these rate constants and on the circulation rate of the liquid. The logarithm of the mass transfer coefficient showed a linear relationship with the logarithm of the gas flow rate. The slope of the line was found to vary according to the relevance of the reaction at the free surface in the vacuum chamber. A linear relationship between the volumetric mass transfer coefficient and the nozzle Reynolds number was also observed. The slopes of the lines changed according to the relative importance of the two reaction sites, gas-liquid interface in the upleg snorkel and in the vacuum. At higher Reynolds number, the reaction in the vacuum chamber tends to be more significant.

Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column

2019 ◽  
Vol 41 (5) ◽  
pp. 820-820
Author(s):  
Pongayi Ponnusamy Selvi and Rajoo Baskar Pongayi Ponnusamy Selvi and Rajoo Baskar
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Aqueous Ammonia ◽  
Volume Flow Rate ◽  
Packed Column ◽  
Operating Conditions ◽  
Co2 Absorption ◽  
Absorption Column

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.

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