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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01 Jan 2012
TL;DR: A backmixing-diffusion model was developed and proposed to describe the mass transport in a reversing continuous countercurrent extrac-tor (RCCE) at steady-state condition as discussed by the authors.
Abstract: A backmixing-diffusion model was developed and proposed to describe the mass transport in a reversing continuous countercurrent extrac- tor (RCCE) at steady-state condition. Three variables namely draft, retention time, and extraction temperature were studied according to various experi- mental trials. Equilibrium distribution coefficient and solute diffusivity were important parameters introduced to predict concentration profiles for both liquid and solid phases. It was found that backmixing-diffusion concept can be applied through the studied range of operation time. The differences between experimental data and the predictions for concentration profiles were due to the variations in Biot number and Peclet number along the length of extraction unit. Nevertheless, the simulation was successful for pineapple juice extraction process.
Patent•
15 Jun 2011
TL;DR: In this article, the authors proposed a heat exchanger consisting of two or more evaporation areas around a heat exchange fan, and the pipelines of the first branch and the second branch are arranged in the same area.
Abstract: The invention relates to an evaporator structure comprising a heat exchanger, wherein the heat exchanger comprises two or more evaporation areas around a heat exchange fan, refrigerant flowing pipelines repeatedly penetrated in the heat exchanger, a refrigerant inlet and a refrigerant outlet; the refrigerant flowing pipelines are communicated in the two or more evaporation areas through a crossunder pipe and are divided into a first branch and a second branch through the crossunder pipe and a Tee; the first branch is connected with a first capillary; the second branch is connected with a second capillary; parts of refrigerant flowing pipelines of the first branch and the second branch are arranged in the same evaporation area; and the two or more evaporation areas include a heat exchange area with largest surface air distribution in which the same evaporation area is arranged. Compared with the traditional countercurrent flow heat exchange evaporator, the refrigeration quantity of theevaporator structure is increased by 15%, and the energy efficiency ratio is increased by 13%.
Patent•
25 Jan 2018
TL;DR: In this article, a shell-and-tube countercurrent heat exchanger is proposed to heat the raw vapours in the processes of dehydrogenation of paraffin hydrocarbons C-C.
Abstract: FIELD: chemistry.SUBSTANCE: invention relates to the shell-and-tube countercurrent heat exchanger to heat the raw vapours in the processes of dehydrogenation of paraffin hydrocarbons C-Cby the heat of contact gas coming from the dehydrogenation reactor comprising a vertical cylindrical casing (), a bundle of the heat exchanging tubes (2) with an upper (4) and a lower (3) tube gratings, a nozzle (5) and a distributing chamber (6) to input the contact gas in the upper part of the tube space (2) of the heat exchanger (11), a collecting chamber (7) and a nozzle (8) to output the chilled contact of gas from the lower part of the tube space, as well as nozzles (9) to input vapours of the raw material in the annular space of the heat exchanger (11), divided into sections by transverse horizontal partitions of the segment type (13), and to output (10) the heated vapours of raw materials from it. The heat exchanger is also characterized by the fact that the heat exchanger (11) contains connections (12) to supply a part of the feed raw material in a liquid form for the heat exchanger (11) into the intertube space of the bundle of the heat exchange tubes (2) and/or into the intertube space of the bundle of the heat exchange tubes (2) divided by sectors (17), which are limited to the upper (4) and lower (3) tube gratings and vertical channels (18) between the sectors (17). A version of a shell-and-tube heat exchanger for cooling the contact gas is also proposed.EFFECT: increase in capacity of dehydrogenation plants of hydrocarbons C-Cand reducing the costs in production.22 cl, 6 dwg, 8 ex, 2 tbl
DOI•
23 Nov 2021
TL;DR: In this article, the authors investigated another possibility for air water generators using absorption and reverse osmosis and showed that the reverse Osmosis membrane modules operated in countercurrent generally have a lower energy demand and require fewer reverse oasmosis stages than those operated in co-current.
Abstract: Technologies for obtaining drinkable water are becoming more important as global water consumption steadily increases and climate change progresses. One possibility for obtaining water is the extraction of water vapor from ambient air by means of air water generators (AWG). Previous studies in the field of AWG have mainly dealt with the condensation of humidity on cold surfaces with a cooling system or with absorption and thermal desorption. In this paper, another possibility for AWG is investigated, specifically AWG using absorption and reverse osmosis. For this purpose, models have been set up for an absorber operated in countercurrent and reverse osmosis membrane modules operated in co-current and countercurrent. With these models, simulations with different boundary conditions were then carried out using the programming language Python. The simulations have shown that the reverse osmosis membrane modules operated in countercurrent generally have a lower energy demand and require fewer reverse osmosis stages than those operated in co-current.