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Showing papers on "Countercurrent exchange published in 2015"


Journal ArticleDOI
TL;DR: In this article, a thermodynamic model of the ceria-based solar thermochemical redox cycle is presented with the objective of resolving the widely varying predictions of the solar-to-fuel efficiency possible with reduction carried out in a flow of inert sweep gas.
Abstract: A thermodynamic model of the ceria-based solar thermochemical redox cycle is presented with the objective of resolving the widely varying predictions of the solar-to-fuel efficiency possible with reduction carried out in a flow of inert sweep gas. The implications of the treatment of the gas–solid interaction are explored through comparison of mixed flow and countercurrent flow configurations of reactants. The mixed flow model is applied for the first time to both reduction and oxidation reactions. The mechanical work to produce sweep gas of varying purity, separate the products, and pump gases is included. The results identify the conditions necessary for efficient operation. The two models lead to substantially different predictions of the usage of sweep gas and oxidizer and process efficiency. Efficiencies predicted with the conservative mixed flow model reach a maximum of 11% for water splitting at 1073 K, assuming reduction at 1773 K, heat recovery of 80% of the sensible heat of the gases, and an opt...

67 citations


Patent
04 Nov 2015
TL;DR: In this article, a hot-air drying machine capable of utilizing waste heat and achieving penetrating countercurrent fluidization is presented. But the work in this paper is limited to a single application.
Abstract: The invention discloses a hot-air drying machine capable of utilizing waste heat and achieving penetrating countercurrent fluidization. The upper portion of a drying tower is connected with an induced draft fan, and the induced draft fan is connected with a cyclone dust removing waste heat efficient recoverer formed by a tube-type heat exchanger and a cyclone dust collector in an overlapped manner in the tangent direction and then is emptied; the air inlet end of the shell side of the tube-type heat exchanger is communicated with the atmosphere, and the air outlet end of the shell side of the tube-type heat exchanger is connected with the lower portion of the drying tower through an air blower and a steam finned heater; and an impeller of the induced draft fan is of a structure that blades are in a hollow and wedged shape and the backing plate is in a disc shape, and the contour line of the appearance of the induced draft fan is an evolvent. According to the hot-air drying machine capable of utilizing the waste heat and achieving the penetrating countercurrent fluidization, creative integration is conducted on waste heat utilization and dust removal, the cyclone dust removing waste heat efficient recoverer is designed out, the equipment input is reduced, and the work efficiency is improved; and due to the fact that sieve mesh cone covers, sieve mesh cone discs, discharging tubes, a stretching vibration transmission shaft and conical plugs are arranged, penetrating, countercurrent, boiling and fluidization drying of materials are exquisitely and perfectly achieved, more energy is saved, the drying quality is higher, the power consumption of the induced draft fan is lower, and the application prospect is wider.

44 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated CO2 removal by single and blended amines in a hollow-fiber membrane contactor (HFMC) under gas-filled and partially liquid-filled membrane pores conditions via a two-scale, nonisothermal, steady-state model accounting for CO2 diffusion in gasfilled pores.
Abstract: This work investigates CO2 removal by single and blended amines in a hollow-fiber membrane contactor (HFMC) under gas-filled and partially liquid-filled membrane pores conditions via a two-scale, nonisothermal, steady-state model accounting for CO2 diffusion in gas-filled pores, CO2 and amines diffusion/reaction within liquid-filled pores and CO2 and amines diffusion/reaction in liquid boundary layer. Model predictions were compared with CO2 absorption data under various experimental conditions. The model was used to analyze the effects of liquid and gas velocity, CO2 partial pressure, single (primary, secondary, tertiary, and sterically hindered alkanolamines) and mixed amines solution type, membrane wetting, and cocurrent/countercurrent flow orientation on the HFMC performance. An insignificant difference between the absorption in cocurrent and countercurrent flow was observed in this study. The membrane wetting decreases significantly the performance of hollow-fiber membrane module. The nonisothermal simulations reveal that the hollow-fiber membrane module operation can be considered as nearly isothermal. © 2014 American Institute of Chemical Engineers AIChE J, 61: 955–971, 2015

43 citations


Journal ArticleDOI
TL;DR: A mathematical model has been developed to characterize the multi-component CO2 capture from natural gas adapting hollow fiber membrane module for the radial crossflow, countercurrent and cocurrent flow.

42 citations


Journal ArticleDOI
TL;DR: In this paper, a general mathematical model of countercurrent multiple effect evaporation (MEE) system contains various energy saving measures simultaneously (such as steam jet heat pump technology, solution flash and condensed water flash) is established.

39 citations


Journal ArticleDOI
TL;DR: In this paper, electrical capacitance tomography was used to study the hydrodynamics of the inclined bed, which was randomly packed with small packings, subject to gas-liquid countercurrent flow for different column inclination angles and liquid-feed nozzle positions, while sweeping fluid throughputs ranged to encompass trickling flow up to the flooding point.

27 citations


Journal ArticleDOI
TL;DR: In this paper, removal of hydrogen sulfide (H2S) and carbon dioxide (CO2) from simulated syngas has been studied on one column scrubbing system.

27 citations


Journal ArticleDOI
TL;DR: In this paper, the separation of the countercurrent hollow fiber membrane module has been characterized adapting a multi-component Progressive Cell Balance (PCB) approach and incorporated within the Aspen HYSYS process simulator.

26 citations


Journal ArticleDOI
TL;DR: In this article, a single stage silica membrane in three flow patterns, namely cocurrent, countercurrent and cross flow, was used for hydrogen separation from methanol steam reforming products to produce high purity hydrogen.
Abstract: The main aim of this work is the presentation of quantitative analysis of silica membrane for hydrogen separation from methanol steam reforming products to produce high purity hydrogen This study uses a single stage silica membrane in three different flow patterns, namely cocurrent, countercurrent and cross flow, for separation of a typical methanol steam reforming products stream The modeling results showed that the silica membrane presents noticeable performance to produce high purity hydrogen In particular, by considering the stage cut, it was found that the hydrogen molar fraction in the permeate side was decreased by increasing the stage cut from 01 to 065, whereas the carbon monoxide molar fraction increased for all of the flow patterns In addition, a similar effect was observed for membrane surface area Moreover, the retentate side pressure effect was positive on the silica membrane performance, although the improvement of silica membrane performance was not considerable for more than a pressure gradient of 3 bar This analysis indicated that by using single stage silica membrane, 99% hydrogen molar fraction and 04% carbon monoxide molar fraction in the permeate side can be achieved for a pressure gradient equal to 3 bar © 2015 Curtin University of Technology and John Wiley & Sons, Ltd

23 citations


Journal ArticleDOI
TL;DR: In this paper, an analytical model was developed that describes the module-level performance (i.e., water recovery rate and separation factors of the feed and draw solutes) for cocurrent and countercurrent forward osmosis systems in the thermodynamic limit of osmotic equilibrium.
Abstract: Forward osmosis processes are an emerging set of technologies that show promise in the treatment of complex and impaired water streams (e.g., those encountered in industrial wastewater treatment and the extraction of unconventional oil resources). The effective operation of these systems requires that the operating conditions be chosen wisely based on the membrane to be used and the streams to be treated. In this work, to aid in the design of these systems, an analytical model was developed that describes the module-level performance (i.e., water recovery rate and separation factors of the feed and draw solutes) for cocurrent and countercurrent forward osmosis systems in the thermodynamic limit of osmotic equilibrium. In the limit of osmotic equilibrium, the model expresses the recovery rate and separation factors in terms of the operating conditions (e.g., the flow rates and concentrations of the feed and draw solutions) and the characteristic membrane transport properties (e.g., the hydraulic and solute...

18 citations


Journal ArticleDOI
TL;DR: In this article, a hollow-fiber membrane contactor was evaluated to remove ammonia traces from water used for hydrogen production by electrolysis, and three operational parameters were evaluated: the feed flow rate, the initial ammonia concentration in the water stream, and the pH of solution.
Abstract: In this work, a liquid–liquid membrane contactor (LLMC) was evaluated to remove ammonia traces from water used for hydrogen production by electrolysis. Three operational parameters were evaluated: the feed flow rate, the initial ammonia concentration in the water stream, and the pH of solution. Synthetic aqueous solutions with ammonium concentration of 5–25 mg L−1 and a sulfuric acid solution (pH 2) were supplied to the LLMC in countercurrent and open-loop configuration with flow rates between 2.72 × 10−6 and 22.6 × 10−6 m3 s−1 and the pH values of the solution with ammonium between 8 and 11. A 2D numerical model was developed considering advection–diffusion equation inside a single fiber of the lumen with fully developed laminar flow and liquid–gas equilibrium in the membrane–solution interface. Predictions of the model were then validated against experimental data, which were found to be in good agreement. According to both, experimental data and numerical predictions, the hollow-fiber membrane ...

Journal ArticleDOI
TL;DR: In this paper, a membrane-based supercritical fluid extraction for the removal of fermentation products from an ABE (acetone/butanol/ethanol) mixture was implemented in a hollow fiber contactor where the liquid fed was circulated in the lumenside.
Abstract: This work is focused on the application of membrane-based supercritical fluid extraction for the removal of fermentation products from an ABE (acetone/butanol/ethanol) mixture. The extraction process was implemented in a hollow fiber contactor where the liquid fed was circulated in the lumenside. Meanwhile, the extraction phase was dense carbon dioxide, circulated through the shell. A model solution, containing the three representative products of ABE fermentation broths was fed to the single PTFE fiber contactor with flow rates varying from 0.1 to 1.5 mL min −1 . Dense CO 2 with pressures between 7.0 and 9.0 MPa at 40 °C was circulated in countercurrent configuration. Experimental extraction percentages reached 70%, 50% and 27% for acetone, butanol and ethanol, respectively, in a single extraction step. When pressure was 9.0 MPa and liquid feed flow rate was higher than 0.5 mL min −1 , the extraction percentage of solutes and its transmembrane fluxes showed an unexpected decreasing, which was described by means of a phenomenological transfer model with variable membrane wettability. Thus, it has been demonstrated that the higher flow rates and pressure values can involve instability of the interface formed at the pore entrance and the liquid feed solution can penetrates into the membrane pores.

Journal ArticleDOI
TL;DR: In this article, a new method of dynamic countercurrent cyclic extraction is proposed, where a mixture of components to be separated is injected with one of the phases during a certain time period, which does not exceed the time of this phase motion stage in the initial process cycle.
Abstract: This paper deals with a new method of dynamic countercurrent cyclic extraction. Each cycle consists of two lightand heavy-phase motion stages. The time of each phase is variable and must be specified for each process cycle. A mixture of components to be separated is injected with one of the phases during a certain time period, which does not exceed the time of this phase motion stage in the initial process cycle. A mathematical model of dynamic countercurrent cyclic extraction is developed. Some analytical relationships for calculating the separation of liquid mixtures by this method are derived. The proposed dynamic regime of extraction has been established to considerably (by several times) increase the operational efficiency of extraction units. A comparison of the experiment and theory demonstrates satisfactory agreement between them.

Journal ArticleDOI
Sameh A. Nada1
TL;DR: In this paper, an experimental investigation of cooling a very hot vertical tube by sudden introduction of a falling liquid film in the presence of a countercurrent flow of rising hot gases air is presented.


Journal ArticleDOI
TL;DR: In this article, an upscaled description of solute concentration transport processes in countercurrent dialyzer systems by means of a porous media approach based on the volume averaging theory was derived.

Journal ArticleDOI
Bo Liu1, Xingang Li1, Zhongyuan Li1, Hong Sui1, Hong Li1 
TL;DR: In this article, the fluidization performance of liquid-solid countercurrent solvent extraction in an extraction column (2.1m × 50mm diameter) with the solvent and solid flow rates ranging from 10 to 800 lh−1 and from 8 to 107 lh −1, respectively, was investigated.
Abstract: Liquid–solid countercurrent solvent extraction is a potential application way for the removal of oil pollutant from contaminated soil. This study focuses primarily on the fluidization performance of liquid–solid two-phase flow in an extraction column (2.1 m × 50 mm diameter), with the solvent and solid flow rates ranging from 10 to 800 L h−1 and from 8 to 107 kg h−1, respectively. Several key hydrodynamic parameters, including pressure drop, solid holdup, superficial velocity of the solvent and solid, and dimensionless slip velocity, were investigated experimentally. At a given solid flow rate, a uniform axial distribution of solid holdup was observed at low solvent flow rate, whereas the axial solid holdup gradient increased with the solvent flow rate. The appearance of a solid holdup gradient was mainly attributed to the presence of small particles. An operating curve for the soil remediation by countercurrent solvent extraction was obtained according to the critical flow rate of the solvent and solid for predicting the occurrence of flooding and the appearance of the solid holdup gradient.


Journal ArticleDOI
TL;DR: In this paper, a liquid-liquid countercurrent centrifugal extractor with Taylor vortices was developed for high-performance extraction of lanthanides (Sm and Eu) with D2EHPA.

Journal ArticleDOI
TL;DR: In this article, a bundle of topologically arranged tubes based on fractal is proposed to enhance the flow of shell-side fluid, where the space for arranging tubes is separated into some periodic regions and the tubes are symmetrically arranged in these regions.


Patent
03 Jun 2015
TL;DR: In this paper, a heating gas aluminum melting furnace energy-saving combustion system is described, which comprises a furnace body, a nozzle, a flue pipeline, a first heat exchanger and a second heat exchangers, where the preheated combustion air is conveyed to the nozzle by the pipeline for supporting combustion.
Abstract: The invention discloses a heating gas aluminum melting furnace energy-saving combustion system, which comprises a furnace body, a nozzle, a flue pipeline, a first heat exchanger and a second heat exchanger, wherein the first heat exchanger is provided with a first air port and a second air port; the second heat exchanger is provided with a third air port and a fourth air port; two air ports of a pair of combination formed by any two air ports selected from the first air port, the second air port, the third air port and the fourth air port, except the pair of combination formed by two adjacent air ports, are connected through a communication pipe; any one of the two rest air ports is used as a cold air inlet and the other one is used as a hot air outlet, so that combustion air is firstly subjected to fair current heat exchange or countercurrent heat exchanger with flue gas in one of the first heat exchanger and the second heat exchanger, and then the combustion air is subjected to fair current heat exchange or countercurrent heat exchanger with flue gas in the other of the first heat exchanger and the second heat exchanger, and the preheated combustion air is conveyed to the nozzle by the pipeline for supporting combustion

ReportDOI
01 Aug 2015
TL;DR: In this article, the authors present a packed particle bed recirculator and heat exchanger, which is intended to create countercurrent flows of packed particle beds and exchange heat between the flows.
Abstract: In this report we present the development of a packed particle bed recirculator and heat exchanger. The device is intended to create countercurrent flows of packed particle beds and exchange heat between the flows. The project focused on the design, fabrication, demonstration, and modifications of a simple prototype, in order to attain high levels of heat exchange between particle flows while maintaining an effective particle conveying rate in a scalable package. Despite heat losses in a package not optimized for heat retention, 50% heat recovery was achieved, at a particle conveying efficiency of 40%.

Patent
28 Oct 2015
TL;DR: In this paper, a system for recovering water in high-humidity flue gas by contact-type circulating heat exchange and removing PM25 at the same time is presented, where the adsorbents can be recycled after contact heat exchange, so that the purposes of saving water resources and protecting the environment are achieved.
Abstract: The invention discloses a system for recovering water in high-humidity flue gas by contact-type circulating heat exchange and removing PM25 at the same time A contact-type heat exchanger is additionally arranged at an outlet of a desulfurization tower in a thermal power plant; a high-pressure overcooled liquid adsorbent enters the heat exchanger and is subjected to countercurrent contact-type heat exchange with desulfurization flue gas in a filler layer; and PM25 in the flue gas is attached on the pipe wall of the heat exchanger and immersed in condensed liquid, and flows down along with the condensed liquid to be collected A gas adsorbent is boosted through a compressor and condensed through a condenser to become high-pressure overcooled liquid; and the high-pressure overcooled liquid is filtered through a dry filter and decompressed through a throttle valve to enter the heat exchanger for continuing to circularly exchange heat with the desulfurization flue gas According to the system, the adsorbents are used for recovering the water in the desulfurization flue gas and performing capture settling on PM25 at the same time; and the adsorbents can be recycled after contact heat exchange, so that the purposes of saving water resources and protecting the environment are achieved

Patent
04 Mar 2015
TL;DR: In this article, a temperature differential engine (TDE) is used to transfer thermal energy into mechanical energy. But the authors focus on the low-boiling-point medium steam turbine and the heat absorber.
Abstract: A temperature differential engine device includes a low-boiling-point medium steam turbine (1), a heat absorber (2), a thermal-insulating type low-temperature countercurrent heat exchanger (3), a circulating pump (4), and a refrigerating system (5) which are interconnected to constitute a closed circulating system filled with low-boiling-point medium fluid. The low-boiling-point medium steam turbine (1) and the heat absorber (2) constitute a low-density-medium heat-absorbing working system, and the circulating pump (4) and the refrigerating system (5) constitute a high-density-medium refrigerating-circulating system. The temperature differential engine device can transfer thermal energy into mechanical energy.

Patent
04 Nov 2015
TL;DR: In this article, a heat pump type drying machine capable of utilizing waste heat and achieving penetrating countercurrent is presented. But the work efficiency of the system is limited by the number of axial fans and axial fan blades.
Abstract: The invention discloses a heat pump type drying machine capable of utilizing waste heat and achieving penetrating countercurrent. An air draft hood and an air inlet hood are arranged at the two ends of a drying machine case body respectively, the air draft hood is connected with an induced draft fan, and the induced draft fan is connected with an evaporator of a heat pump system through a cyclone dust collector and then is emptied; the evaporator of the heat pump system is connected with a host through a refrigerant pipe, and the host is connected with a condenser through the refrigerant pipe; the air outlet end of an air blower is connected with the air inlet hood through a condenser; and multiple soft partition plates which are vertically arranged and divide an upper machine case body and a lower machine case body into multiple units are arranged in the drying machine case body. According to the heat pump type drying machine capable of utilizing the waste heat and achieving the penetrating countercurrent, by means of the induced draft fan, the partition plates and axial fans, the penetrating countercurrent drying is exquisitely achieved, and the work efficiency is improved; the heat pump type waste heat utilization is suitable for heat recovery of tail gas with lower temperature and is particularly efficient, convenient and rapid; and by means of the structure that blades are in a hollow and wedged shape and the backing plate is in a disc shape, real-time cleaning of dust on an impeller is achieved, the impeller strength of the induced draft fan is increased, the stability is enhanced, safety accidents caused by dust accumulation is effectively eradicated, and the application prospect is wide.

Patent
04 Feb 2015
TL;DR: In this paper, the authors presented a double-effect countercurrent ammonia concentration device with three evaporators and two condensers, which mainly consisted of a primary evaporator, a control evaporation, a secondary evaper, a primary condenser and a secondary condenser.
Abstract: The utility model discloses a double-effect countercurrent ammonia concentration device. The double-effect countercurrent ammonia concentration device mainly comprises three evaporators and two condensers, namely a primary evaporator, a control evaporator, a secondary evaporator, a primary condenser and a secondary condenser. The utility model provides a double-effect countercurrent evaporation method through optimization and innovation on the basis of the traditional double-effect evaporation device, namely the primary evaporator is heated by using steam of the secondary evaporator, use of ammonia-containing water vapor which is inconvenient to use is avoided, and secondary steam of which ammonia is clearly removed is used. Therefore, the energy-saving efficiency of the device is over 30 percent in the production process.

Patent
25 Feb 2015
TL;DR: In this paper, an MVR evaporation and concentration and ultrasonic countercurrent extraction production line is presented, which is used for extracting active ingredients in medicinal materials and liquid medicine via reasonable structural arrangement.
Abstract: The invention provides an MVR evaporation and concentration and ultrasonic countercurrent extraction production line. According to the production line, an ultrasonic countercurrent extraction device used for extracting active ingredients in medicinal materials is effectively combined with an MVR evaporation and concentration device used for liquid medicine via reasonable structural arrangement, so that the MVR evaporation and concentration and ultrasonic countercurrent extraction production line disclosed by the invention has the advantages of energy conservation, effective extraction and concentration and solvent recovery and environment friendliness compared with the prior art, and the production cost of enterprises is further reduced.

Patent
27 May 2015
TL;DR: In this article, a continuous countercurrent differential extraction method and a CCD extraction device are presented. But the method is not suitable for industrial applications, and the problems that the industrial extraction operation process is complicated and the production cost is high in the prior art can be solved.
Abstract: The invention discloses a continuous countercurrent differential extraction method and a continuous countercurrent differential extraction device. The continuous countercurrent differential extraction device comprises a material mixer, a continuous countercurrent differential extraction tower, a heavy-phase solution receiver and a light-phase solution receiver; the continuous countercurrent differential extraction tower is a cylindrical tower body which is vertically arranged, the tower body is divided into an upper section, a middle section and a lower section, and each section is provided with a temperature measuring device; the upper section of the tower body is provided with a cooling device, the middle section of the tower body is provided with a feeding device, the lower section of the tower body is provided with a heating device, a discharging opening is formed in the bottom of the tower body, the discharging opening is connected with the heavy-phase solution receiver, an overflow opening is formed in the top of the tower body, and the overflow opening is connected with the light-phase solution receiver. According to the method, a to-be-separated substance is mixed with a light-phase solvent and a heavy-phase solvent to obtain a mixture, then the mixture is inputted into the continuous countercurrent differential extraction device at a given flow rate, and the continuous countercurrent differential extraction is carried out on the mixture. By adopting the continuous countercurrent differential extraction method and the continuous countercurrent differential extraction device, few solvent is needed, and the problems that the industrial extraction operation process is complicated and the production cost is high in the prior art can be solved.