scholarly journals Kinetics of nitrous oxide mass transfer from porewater into root aerenchyma of wetland plants

2020 ◽  
Vol 49 (6) ◽  
pp. 1717-1729
Author(s):  
Simiao Wang ◽  
Matthew C. Reid
Keyword(s):  
Mass Transfer ◽  
Nitrous Oxide ◽  
Wetland Plants ◽  
Root Aerenchyma ◽  
Kinetics Of

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 and kinetics of H 2 O 2 direct synthesis in a batch slurry reactor

2012 ◽  
Vol 207-208 ◽  
pp. 539-551 ◽  
Author(s):  
Nicola Gemo ◽  
Pierdomenico Biasi ◽  
Paolo Canu ◽  
Tapio O. Salmi
Keyword(s):  
Mass Transfer ◽  
Direct Synthesis ◽  
Slurry Reactor ◽  
Kinetics Of

Physical kinetics of coal-methane system: Mass transfer, pre-outburst events

2014 ◽  
Vol 50 (3) ◽  
pp. 448-464 ◽  
Author(s):  
E. P. Fel’dman ◽  
T. A. Vasilenko ◽  
N. A. Kalugina
Keyword(s):  
Mass Transfer ◽  
Kinetics Of

Consequences of mass transfer effects on the kinetics of nitrifiers

2005 ◽  
Vol 39 (19) ◽  
pp. 4633-4642 ◽  
Author(s):  
Reto Manser ◽  
Willi Gujer ◽  
Hansruedi Siegrist
Keyword(s):  
Mass Transfer ◽  
Transfer Effects ◽  
Kinetics Of

scholarly journals Modeling of the adsorption kinetics of zinc onto granular activated carbon and natural zeolite

2006 ◽  
Vol 71 (8-9) ◽  
pp. 957-967 ◽  
Author(s):  
Ljiljana Markovska ◽  
Vera Meshko ◽  
Mirko Marinkovski
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Simulation Study ◽  
Natural Zeolite ◽  
Granular Activated Carbon ◽  
Model Parameters ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Kinetics Of

The isotherms and kinetics of zinc adsorption from aqueous solution onto granular activated carbon (GAC) and natural zeolite were studied using an agitated batch adsorber. The maximum adsorption capacities of GAC and natural zeolite towards zinc(II) from Langmuir adsorption isotherms were determined using experimental adsorption equilibrium data. The homogeneous solid diffusion model (HSD-model) combined with external mass transfer resistance was applied to fit the experimental kinetic data. The kinetics simulation study was performed using a computer program based on the proposed mathematical model and developed using gPROMS. As the two-mass transfer resistance approach was applied, two model parameters were fitted during the simulation study. External mass transfer and solid phase diffusion coefficients were obtained to predict the kinetic curves for varying initial Zn(II) concentration at constant agitation speed and constant adsorbent mass. For any particular Zn(II) - adsorbent system, k f was constant, except for the lowest initial concentration, while D s was found to increase with increasing initial Zn(II) concentration.

scholarly journals Study of the Moisture Bond Forms in Cheeses

2020 ◽  
Vol 11 (3) ◽  
pp. 11054-11065
Keyword(s):  
Mass Transfer ◽  
Energy Consumption ◽  
Binding Energy ◽  
Strain Gauge ◽  
Bound Water ◽  
The State ◽  
Point Of View ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Kinetics Of

The article is devoted to the study of the forms of moisture bond in mature cheeses. The kinetics of mass transfer processes depend on the mobility and binding energy of water with solid and dissolved substances. Therefore, the removal of bound water is accompanied by deterioration in kinetics and increased energy consumption. In this regard, information on the state of bound water in substances during dehydration is very important from a scientific point of view and from a practical one. Based on the studies carried out, the forms of moisture bond in various types of cheese were determined by strain-gauge and thermographic methods. Based on this, it has been established that the forms of moisture bond in cheeses can be determined by strain-gauge and thermographic methods.

Sign in / Sign up

Export Citation Format

Share Document