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.

Countercurrent Transfer Processes in the Non-Steady State

Abstract: Countercurrent mass and heat-transfer operations are analyzed mathematically, taking into account column capacity, and a general solution is obtained which enables the course of non-steady conditions to be followed quantitatively for a wide class of processes. Absorption and extraction, continuous distillation and batch distillation, are treated in detail, and illustrative examples are provided of the behaviour of a typical heat exchanger and of a typical batch distillation process.

A parametric study to numerically analyze the formation damage effect

Abstract: Spontaneous countercurrent imbibition is one of the essential parameters in the study of formation damage effect in hydrocarbon reservoirs when the drilling fluid is contacted with the drilled form...

Two-stage combined cocurrent-countercurrent gasifier

Abstract: Two-stage combined cocurrent-countercurrent gasifier, which is used for the thermochemical process that converts solid carbonaceous materials into combustible gases, has as first (pyrolysis) stage a countercurrent reactor (1) placed above the second (gasification) stage which is a cocurrent reactor (2) and is characterized in that between the two stages a diaphragm (3) is present, which cuts off the gaseous flow between the countercurrent reactor (1) and the cocurrent reactor (2), while allowing the solid pieces falling from the countercurrent reactor (1) to pass to the cocurrent reactor (2). From the measurements of the physical parameters at the discharge (11) of the pyrolysis gases (vapor, volatiles) we have an immediate image of the composition and/or the humidity of the new incoming fuel, thus the automatic control and the safe operation of the process are achieved by setting the air and/or fuel feed of the countercurrent reactor. Thereby variations in the composition and/or humidity of the incoming fuel are balanced and settled quantities of charcoal and gases are supplied to the next process stages, thus it is easy to control all the gasification process. The burning torch (12) of gases coming from the countercurrent reactor (1), is placed so that to introduce the flame into the cocurrent reactor (2) by horizontal setting. The upper part (14) of the cocurrent reactor (2) is configured so that to expand the flue gases of the burning torch (12) by cyclonic mode.

Membrane/Oil Stripping of VOCs from Water in Hollow‐Fiber Contactor

Abstract: Separation of volatile organic contaminants from water using a microporous hollow-fibermembrane/oil stripping system is evaluated. Countercurrent flow of water and oil on opposite sides of an air-filled gas-permeable membrane is used to concentrate the contaminants in the oil phase. The rate of mass transfer under varying conditions is measured and compared to existing full- and laboratory-scale air-stripping processes, to membrane-extraction processes, and to predictions based on known empirical and theoretical correlations. The correlations can be used as the basis for system design and scale-up. This process incorporates the advantages of other membrane-stripping processes, such as a high surface area to volume ratio for transfer, and independent control of the separate liquid phases. It also overcomes several disadvantages of extraction and stripping processes. There is no contact between the liquid phases and thus no potential for cross-contamination or emulsion formation. The membrane separation of phases prevents flow channeling and flooding present in air-stripping towers. Finally, materials used in this process may be recovered aand recycled, preventing further environmental contamination.