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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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Book ChapterDOI
01 Jan 1995
TL;DR: The design approach described creates a negative feedback system in the exchanger that reduces the effect of the unbalancing factors by a decade or more and has improved performance of a countercurrent heat exchanger from an NTu of 33 to an N tu of 167 with the same basic design.
Abstract: As has been noted by Fleming[1] and others, balanced flow distribution is an important problem in high-efficiency counterflow heat exchangers. The extent of the problem increases rapidly as the desired efficiency is raised and is also more severe with expanding heat exchanger size. The present and future energy and resource crises will place a premium on efficient and economical heat exchanger design. This work describes a technique that has proven extremely effective in reducing the effect of manufacturing tolerances, manifolding effect, and the like on flow imbalance. The technique is applicable to any form of countercurrent heat exchanger and can be employed with little or no added complexity of design. In elementary terms, the design approach described creates a negative feedback system in the exchanger that reduces the effect of the unbalancing factors by a decade or more. In tests, it has improved performance of a countercurrent heat exchanger from an N tu of 33 to an N tu of 167 with the same basic design.

7 citations

Journal ArticleDOI
TL;DR: In this paper, a cyclonic-static micro-bubble flotation column (FCSMC) has been used in mineral separation, which includes countercurrent, cyclone and jet flow mineralization zones in a single column.
Abstract: A cyclonic-static micro-bubble flotation column (FCSMC) has been widely used in mineral separation. FCSMC includes countercurrent, cyclone and jet flow mineralization zones in a single column. In this study, the energy feature of the three different zones was compared. The turbulent flow was evaluated in terms of the turbulent kinetic energy (k) and the turbulent dissipation rate (e). An appropriate computing model was determined by comparing the flow field value measured by PIV with the results of the Fluent numerical simulation. Jet flow separation exhibited the maximum k and e values among the three columns, whereas counter-current separation displayed the minimum values. The high circulating volumetric flowrate means great energy input and turbulent intensity. The higher turbulent dissipation rate, the smaller the bubble is. The better performance of the FCSMC was mainly attributed to the multiple mineralization steps. The floatability of mineral particles gradually decreases with an increase in flotation time, the mineralization energy gradually increased to overcome the decrease in mineral floatability. By contrast, the countercurrent was beneficial for recovering the coarse particles, and the jet flow was beneficial for recovering the fine particles.

7 citations

Journal ArticleDOI
TL;DR: In this paper, a mathematical model for concurrent rotary dryers including heat and mass transfer was developed for ammonium nitrate (AN) drying at the Shiraz Petrochemical Complex (SPC).
Abstract: Drying of ammonium nitrate (AN) is accomplished in the Shiraz Petrochemical Complex (SPC) using a concurrent rotary dryer following a countercurrent rotary dryer. A mathematical model for these rotary dryers including heat and mass transfer was developed. The model was checked against industrial-scale data, which showed a good agreement. The average absolute deviation of the simulation results compared to the industrial data for the concurrent dryer was 4.0% for solids moisture, 1.3% for solids temperature, and 1.8% for air temperature and for the countercurrent dryer it was 9.0% for the solids moisture, 2.0% for solids temperature, and 4.6% for air temperature. These simulation results reveal that for outlet solid moisture, inlet AN moisture, and air temperature as well as the outlet temperature of product, the inlet solid and air temperature have major effects for both concurrent and countercurrent flow.

7 citations

Book ChapterDOI
TL;DR: In this article, the authors show that when the separation factor of the mixture is small and the desired productivities are large, the first process is usually economically preferable with respect to the second one in spite of the additional cost associated with the more complex plant required by the countercurrent operation.
Abstract: As for most two-phase operations, also in adsorption separation processes continuous countercurrent contact is often preferred to the cyclic batch operation mode. When the separation factor of the mixture is small and the desired productivities are large, the first process is usually economically preferable with respect to the second one in spite of the additional cost associated with the more complex plant required by the countercurrent operation [1,2].

7 citations


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