Topic
Countercurrent exchange
About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.
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TL;DR: In this article, the experimental and modeling studies of hydrodynamics in a continuous countercurrent liquid-solid system were conducted and the hydrodynamic variables considered are the pressure drop, phase holdup and flooding velocities.
Abstract: The present work deals with the experimental and modeling studies of hydrodynamics in a continuous countercurrent liquid–solid system. The hydrodynamic variables considered are the pressure drop, phase holdup and flooding velocities. It is observed that the pressure drop and solid holdup in the system increase with increase in phase velocities and decrease with increase in particle diameter and density. The one-dimensional two-fluid model comprising of continuity and momentum equations for each phase with the most suitable drag law closure is used to predict the axial pressure drop profile and the effect of operating variables and particle characteristics on solid holdup. The model predicts satisfactorily the experimental data of the present study and those reported in the literature over a wide range of fluid and particle characteristics. The model also captures the trends of the hydrodynamic variables with the independent parameters.
6 citations
TL;DR: In this paper, the hydrodynamics of the downward motion of a liquid film in vertical tubes in an air-vapor countercurrent was investigated. And the theoretical relationship for the liquid-film thicknesses and the tube-break-up density was derived.
Abstract: Results from experimental investigation into the hydrodynamics of the downward motion of a liquid film in vertical tubes in an air-vapor countercurrent are presented. In addition, we have derived the theoretical relationships for the liquid-film thicknesses and the tube-“break-up” density.
6 citations
Patent•
24 Feb 1982
TL;DR: In this article, the authors proposed to recover the unrecovered and dissipated heat energy and obtain a sufficient heat source, by passing a high-temperature gas containing SO3 through a newly installed hightemperature absorbing column, and then passing the gas through a low-time temperature absorbing column.
Abstract: PURPOSE:To recover the unrecovered and dissipated heat energy and obtain a sufficient heat source, by passing a high-temperature gas containing SO3 through a newly installed high-temperature absorbing column, and then passing the gas through a low-temperature absorbing column CONSTITUTION:The sensible heat of a high-temperature gas containing SO3 after the completion of the reaction in a converter 6 is recovered by a heat exchanger 9 and an economizer 10 to 220-160 degC The gas is then brought into the countercurrent contact with high-temperature sulfuric acid in a high-temperature absorbing column 11 to absorb the sensible heat of the gas and the heat generated by the condensation and absorption of SO3 by a circulating acid The discharged gas is then treated with an absorbing column 12 in which sulfuric acid is sprinkled at 75-85 degC, and the same operations are carried out in a heat exchanger 13, economizer 14, high-temperature absorbing column 15 and 16 in the same manner as in the apparatus 9-12 The circulating acid heated at a high temperature and concentrated to a high concentration in the columns 11 and 15 is partly fed to a drying column 1 and mostly to a diluting tank 18 where the heat of dilution is generated by the inflow of low-temperature sulfuric acid from the column 1 through a heat exchanger 19 and inflow of the water for adjusting the acid concentration The resultant sulfuric acid is passed through a heat exchanger 20 and sprinkled from the tops of the columns 11 and 15 Water which received the heat is circulated through an evaporator 22 and the heat exchanger 20 operated at 05-20ata, and generated steam is utilized for concentrating phosphoric acid, etc
6 citations
Patent•
06 Sep 1950
6 citations
TL;DR: In this article, it was experimentally proved that the stagnant zone should not be considered as a dead part of the column, but that there is a dynamic exchange between these two portions of flowing solids particles.
Abstract: In countercurrent gas - flowing solids - fixed bed contactors, a fraction of the flowing solids is in motion (dynamic holdup), while the other fraction is resting on the fixed bed elements. In this study it was experimentally proved that the stagnant zone should not be considered as a dead part of the column, but that there is a dynamic exchange between these two portions of flowing solids particles. Combining a mathematical model with tracer experiments, the rate of exchange was determined and it was shown that only a small part (ca. 20 %) of the stagnant region should be considered as a dead one.
6 citations