Precipitation and filtration of zinc, magnesium, copper and aluminium hydroxides

1982 ◽  
Vol 47 (12) ◽  
pp. 3362-3370
Author(s):  
Otakar Söhnel ◽  
Eva Matějčková
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Filtration Resistance ◽  
Filtration Pressure ◽  
Bed Porosity ◽  
The Mean ◽  
Filtration Properties

Filtration properties of batchwise precipitated suspensions of Zn(OH)2, Mg(OH)2 and Cu(OH)2 and continuously precipitated Al(OH)3 were studied. For batchwise precipitated suspensions was verified the theoretically predicted dependence of specific filtration resistance on initial supersaturation and for the continuously precipitated Al(OH)3 the relation between the specific filtration resistance and the mean residence time of suspension in the reactor. Dependences were also recorded between the bed porosity and concentration of precipitated solutions, specific filtration resistance and used filtration pressure and the effect of aging of the batchwise precipitated suspension of Mg(OH)2on its filtration properties. The used CST method for determination of filtration characteristics of Zn(OH)2 suspension was also studied.

Mass Transfer in Liquid in Apparatus with Mobile Packing. Application of Model of Cascade of Ideal Mixers

1994 ◽  
Vol 59 (2) ◽  
pp. 336-344
Author(s):  
Zdeněk Palatý
Keyword(s):  
Mass Transfer ◽  
Residence Time ◽  
Mean Residence Time ◽  
Liquid Velocity ◽  
Dispersion Model ◽  
Velocity Range ◽  
Bed Height ◽  
The Mean ◽  
Determination Of Parameters

The paper deals with the determination of parameters of a cascade of ideal mixers (i.e. their number and mean residence time of liquid in each member) in modelling the liquid flow on a plate with mobile packing. The number of cascade members has been found practically independent of the gas and liquid velocities and the static bed heights in the gas velocity range from 1.0 to 3.5 m s-1, liquid velocity range from 5.36 . 10-3 to 12.5 . 10-3 m s-1, and the range of static bed height from 21 . 10-3 to 47 . 10-3 m. The mean residence time is increased with increasing static bed height and is decreased with increasing velocities of both gas and liquid. The calculated parameters of the model of flow of liquid and the experimental data on desorption of CO2 from water by a stream of air have been used to calculate the values of mass transfer coefficient in liquid which have been compared with those obtained from the dispersion model. The both approaches have been found to give practically identical results.

Nitrogen use efficiency: does a trade-off exist between the N productivity and the mean residence time within species?

2008 ◽  
Vol 56 (3) ◽  
pp. 272 ◽  
Author(s):  
Zhi Y. Yuan ◽  
Han Y. H. Chen ◽  
Ling H. Li
Keyword(s):  
Residence Time ◽  
Nitrogen Use Efficiency ◽  
Mean Residence Time ◽  
Negative Relationship ◽  
Controlled Experiments ◽  
Nitrogen Use ◽  
Trade Off ◽  
N Supply ◽  
Use Efficiency ◽  
The Mean

Nitrogen use efficiency (NUE) can be divided into two components, i.e. N productivity (A) and the mean residence time (MRT). Controlled experiments indicate that there is not a trade-off between A and MRT within species, but this theory has not been well tested in field conditions. Here, we studied the A, MRT and NUE of Stipa krylovii Roshev. in a grassland over 4 years of N fertilisation experimentation. The three parameters (A, MRT and NUE) were significantly related to soil N supply and there was a negative relationship between A and MRT within this species (r = –0.775, P < 0.05), i.e. plants with higher A had lower MRT. Our results showed a trade-off between A and MRT within this Stipa species and this observed trade-off was attributed to different responses of A and MRT to soil fertility.

scholarly journals Submarine Groundwater Discharge From Sediments and Sand Boils Quantified by the Mean Residence Time of a Tracer Injection

2021 ◽  
Vol 9 ◽  
Author(s):  
Michael Schlüter ◽  
Philipp Maier
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Tracer Injection ◽  
Discharge Rates ◽  
Seepage Meter ◽  
Submarine Groundwater ◽  
Sand Boils ◽  
The Mean

To quantify submarine groundwater discharge, we developed an inexpensive automated seepage meter that applies a tracer injection and the computation of the mean residence time. The SGD-MRT is designed to measure a wide range of discharge rates from about 30 to 800 cm³/min and allows minimizing backpressures caused by pipe friction or flow sensors. By modifying the inner volume of the flow-through unit, the range of measurement is adjustable to lower or higher discharge rates. For process control and data acquisition, an Arduino controller board is used. In addition, components like temperature, conductivity, and pressure sensors or pumps extend the scope of the seepage meter. During field tests in the Wadden Sea, covering tidal cycles, discharge rates of more than 700 cm³/min were released from sand boils. Based on the measured discharge rates and numerical integration of the time series data, a water volume of about 400 dm3 with a seawater content of less than 12% was released from the sand boil within 7 h.

Modeling the Mean Residence Time of Liquid Phase in the Gas–Liquid Cyclone

2015 ◽  
Vol 54 (43) ◽  
pp. 10885-10892 ◽  
Author(s):  
Junwei Yang ◽  
Xupeng Zhang ◽  
Guoping Shen ◽  
Jiazhi Xiao ◽  
Youhai Jin
Keyword(s):  
Liquid Phase ◽  
Residence Time ◽  
Mean Residence Time ◽  
The Mean
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