Effect of Drag‐Reducing Polymer on the Rate of Cementation of Copper Ion on Zinc Pellets

Fadali, Olfat A.

doi:10.1002/ceat.200390073

Cited by 2 publications

(1 citation statement)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The use of electrochemical methods to form organic oxidizing agents for denim bleach has been described [13]. Limited scientific information is available about the electrochemical in-situ formation of hypo-halogenites for bleach operations [9,10,16,17]. The in-house preparation of NaOCl also has been described, however the efficiency of the bleach process has been described as rather low [12].…”

Section: Introductionmentioning

confidence: 99%

On-site formation of hypochlorite for indigo oxidation – Scale-up and full scale operation of an electrolyser for denim bleach processes

Bechtold

Turcanu

Campese³

et al. 2005

J Appl Electrochem

View full text Add to dashboard Cite

On-site production of hypochlorite for denim bleach was investigated using undivided unipolar electrolysers. The current efficiency of the electrolysis process was studied at laboratory scale with up to 20 A cell current and at the technical scale using a 1200 A electrolyser. NaCl solutions in the concentration range 0.236-0.944 M NaCl (13.8-55.2 g l )1 ) were used. Anodic current densities up to 400 A m )2 were used. Hypochlorite solutions with active chlorine concentration c(Cl)=0.10-0.12 M were obtained with current efficiency of 58-70%. For denim bleach processes a concentration of active chlorine up to c(Cl)=0.12 M is required. This corresponds to approximately 30 ml l )1 of commercial hypochlorite solution. Electrical energy consumption calculated per kg of active chlorine formed ranges from 5.7 to 8.6 kWh kg )1 . By coupling the electrolyser to a commercial 30 kg capacity drum washing machine the electrochemically prepared oxidant was successfully used in bleach processes. The technique overcomes problems of insufficient reproducibility of bleach, chemical costs and released wasted water due to the use of commercial NaOCl solution.

show abstract

Section: Introductionmentioning

confidence: 99%

On-site formation of hypochlorite for indigo oxidation – Scale-up and full scale operation of an electrolyser for denim bleach processes

Bechtold

Turcanu

Campese³

et al. 2005

J Appl Electrochem

View full text Add to dashboard Cite

show abstract

On turbulent kinetic energy production and dissipation in dilute polymer solutions

et al. 2006

View full text Add to dashboard Cite

Drag reduction by dilute polymer solutions is the most recognized phenomenon in wall-bounded turbulent flows, which is associated with large scales (e.g., velocity scales) in spite of a consensus that polymers act mainly on much smaller scales of velocity derivatives. We demonstrate that drag reduction is only one sort of polymers’ effect on a turbulent flow and show how turbulent velocity and velocity derivatives are altered in the presence of dilute polymers, irrespective of drag reduction phenomena. This is an experimental study on the interaction of dilute polymers with a complex three-dimensional turbulent flow with small mean velocity gradients. Lagrangian data (e.g., velocities and velocity gradients) of flow tracers were obtained by using three-dimensional particle tracking velocimetry in an observational volume in the turbulent bulk region, far from the boundaries. The focus is on aspects related to the turbulent kinetic energy (TKE) production, −⟨uiuj⟩Sij (ui is the fluctuating velocity, ⟨uiuj⟩ is the Reynolds stress tensor, and Sij is the mean rate-of-strain tensor), such as an anisotropy of Reynolds stresses and the alignment of the velocity vector field with respect to the eigenframe of Sij, among others. We base our study on the comparison of turbulent quantities in flows of water and of dilute polymer solution, forced in two distinct ways: frictional forcing by smooth rotating disks and inertial forcing by disks with baffles. The comparison of the results from the water and from the dilute polymer solution flows allows a critical examination of the influence of polymers on the TKE production, viscous dissipation, and the related turbulent properties. We conclude with (i) quantification of the direct effect of polymers on the small scales of velocity derivatives, (ii) evidence of an additional dissipation mechanism by the polymers, which is the main reason for the strong inhibition of the viscous dissipation, 2νs2, in a turbulent bulk, (iii) verification that TKE production does not change if the energy input to the flow is at the scales that are not affected by polymers (e.g., inertial forcing or a very rough wall), and last, (iv) evidence for qualitative modification of the turbulent structure, which is not exhausted by the additional dissipation mechanism.

show abstract

Effect of Drag‐Reducing Polymer on the Rate of Cementation of Copper Ion on Zinc Pellets

Cited by 2 publications

References 16 publications

On-site formation of hypochlorite for indigo oxidation – Scale-up and full scale operation of an electrolyser for denim bleach processes

On-site formation of hypochlorite for indigo oxidation – Scale-up and full scale operation of an electrolyser for denim bleach processes

On turbulent kinetic energy production and dissipation in dilute polymer solutions

Contact Info

Product

Resources

About