Mass transfer coefficient

About: Mass transfer coefficient is a research topic. Over the lifetime, 7827 publications have been published within this topic receiving 168354 citations.

Modeling Ultrasonically Assisted Convective Drying of Eggplant

Abstract: Modeling constitutes a fundamental tool with which to analyze the influence of ultrasound on mass transfer phenomena during drying. In this work, the study of the effect of power ultrasound application on the drying kinetics of eggplant was addressed by using different models based on theoretical (diffusion) or empirical approaches. Drying kinetics of eggplant cylinders (height 20 mm and diameter 24 mm) were carried at 40°C and 1 m/s applying different ultrasonic powers: 0, 6, 12, 19, 25, 31, and 37 kW/m3. The experiments were carried out at least three times at each different ultrasonic power. Shrinkage and sorption isotherms were also addressed in order to attain an optimal description of eggplant drying. Applying ultrasound sped up the drying kinetics. The ultrasonic power was identified as having a significant (p < 0.05) influence on both the effective moisture diffusivity and the mass transfer coefficient, which was well explained by linear relationships. The most complex model, which considered both...

Determination of Mass Transfer Rates in PVDF and PTFE Hollow Fiber Membranes for CO2 Absorption

Abstract: The gas–liquid mass transfer accompanied by chemical reaction was studied in a membrane absorber for the separation of CO2 from mixture gases. The membranes used were made of polytetrafluoroethylene (PTFE) and polyvinylidenefluoride (PVDF) and the aqueous MEA solution was used as an absorbent possessing a high chemical reaction with carbon dioxide. The numerical model for the CO2 concentration profile in a fiber was developed, and the influence of its flux on the external mass transfer resistances, including gas and membrane, was simulated with this numerical model and compared with the experimental results. Experimentally, it is found that absorption rate per surface area was higher in PVDF membrane than that in PTFE membrane because of the non-wetted condition of membrane pore. The membrane pore wetted with an absorbent showed the low absorption performance by high membrane resistance. We could predict the liquid resistance and membrane–gas resistance (external resistance) from experimental and numerica...

Liquid‐solid mass transfer in packed beds with downward concurrent gas‐liquid flow

Abstract: Mass transfer coefficients were determined by measuring the rate of solution of cylindrical 3 or 6 mm benzoic acid tablets into water in the presence of flowing nitrogen, helium, or argon. Gas flow rates varied from 0 to 1.6 kg/(m2·s) and liquid flow rates from 0.5 to 25 kg/(m2·s), resulting in hydrodynamic flow patterns varying from trickle to turbulent pulse types of flow. In the pulse regime, the mass transfer coefficient was markedly affected by gas flow rate but did not depend on gas density explicitly if correlated in terms of an energy dissipation function.