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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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Patent
30 Mar 2010
TL;DR: A mixing chamber has a first inlet through which a first fluid is fed to the mixing chamber, and a second inlet extends and is operative to inject a second fluid into a stream of the first fluid as mentioned in this paper.
Abstract: A method and apparatus for mixing fluids, such as beverage syrup and water, uses countercurrent injection to improve blending of the fluids. A mixing chamber has a first inlet through which a first fluid is fed to the mixing chamber, and a second inlet through which a countercurrent injection nozzle extends and is operative to inject a second fluid into a stream of the first fluid. The countercurrent injection nozzle is equipped with a check valve to control the flow of fluid into the mixing chamber. The mixing chamber may include additional inlets that may be fitted with countercurrent injection nozzles to permit the countercurrent injection of other fluid, such as flavorings, into the stream of the first fluid.

81 citations

Journal ArticleDOI
TL;DR: A baffled membrane module of hollow fiber fabric can supply both countercurrent contacting and flow perpendicular to well spaced hollow fibers as discussed by the authors, which increases the number of transfer units involved in a given separation, and gives mass transfer coefficients typically five times larger than those available with other modules.

80 citations

Patent
17 Jul 1990
TL;DR: In this article, the authors proposed a substantially continuous flow of uniformly distributed hydrogen and hydrocarbon liquid across a densely packed catalyst bed to fill substantially the entire volume of a reactor vessel by introducing the fluids as alternate annular rings of gas and liquid at a rate insufficient to levitate the bed and with catalyst selected by a density, shape and size at a design feed rate of liquids and gas to prevent ebulation of the packed bed at the design feed rates.
Abstract: This invention makes possible substantially continuous flow of uniformly distributed hydrogen and hydrocarbon liquid across a densely packed catalyst bed to fill substantially the entire volume of a reactor vessel by introducing the fluids as alternate annular rings of gas and liquid at a rate insufficient to levitate the bed and with catalyst selected by a density, shape and size at a design feed rate of liquids and gas to prevent ebulation of the packed bed at the design feed rates. Catalysts are selected by measuring bed expansion in a large pilot plant run with hydrocarbon, hydrogen, and catalyst at the design pressures and flow velocities. The liquid and gas components of the feed flow into the bed in alternate annular rings across the full area of the bed. At the desired flow rate, such catalyst continually flows in a plug-like manner downwardly through the vessel by introducing fresh catalyst at the top of the bed by laminarly flowing such catalyst in a liquid stream on a periodic or semicontinuous basis. Catalyst is similarly removed by laminarly flowing catalyst particles in a liquid stream out of the bottom of the bed. Intake for such flow is out of direct contact with the stream of gas flowing through the bed and the flow path is substantially constant in cross-sectional area and greater in diameter by several times than the diameter of the catalyst particles.

80 citations

Journal ArticleDOI
TL;DR: In this paper, experiments were carried out in beds of unconsolidated glass beads and sand through which fluids were flowing in a direction parallel and countercurrent to energy flow, and a relationship was developed between ke and the heat transfer coefficient between fluid and particle.
Abstract: Experimental heat transfer studies were carried out in beds of unconsolidated glass beads and sand through which fluids were flowing. The scope of the measurements included four fluids, helium, air, carbon dioxide, and water liquid at atmospheric pressure in beds packed with four sizes of glass beads, 110, 370, 570, and 1,020 μ and with two sizes of sand, 110 and 240 μ. Flow rates ranged form 1 to 26 lb./(hr. sq.ft.) in a direction parallel and countercurrent to energy flow. The data were interpreted in terms of apparent, effective thermal conductivities of the bed. The values of ke increase significantly with mass velocity of fluid. By considering the mechanism of heat transfer in porous media a relationship was developed between ke and the heat transfer coefficient between fluid and particle. Treatment of the experimental data in this fashion, combined with available information for larger particles, results in a correlation of Nusselt and Reynolds numbers for air that covers the range N = 10−1 to 104.

79 citations

Journal ArticleDOI
TL;DR: In this article, a large-scale three-channel flowing-liquid-membrane module (selective membrane valve), designed for gas separation, is also described, which consists of PVTMS or PDMS/PPSQ non-porous membranes which acted as gas-permeable barriers.

78 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202358
2022115
202127
202041
201947
201849