Showing papers on "Countercurrent exchange published in 2017"

Modeling and Experimental Study of Carbon Dioxide Absorption in a Flat Sheet Membrane Contactor

Abstract: comIn the present study, CO2 removal from natural gas stream has been studied using a flat sheet membrane contactor. A three dimensional mathematical model is developed to describe the process. The model considers the transport of a gas mixture containing carbon dioxide and methane through a flat sheet membrane contactor module. The model is based on the non-wetted mode of operation, in which the gas fills the membrane pores in a countercurrent gas-liquid contact. Simulation was performed using computational fluid dynamics (CFD) of the model material and momentum transport equations in the flat sheet membrane for laminar flow conditions. Physical and chemical absorptions were considered in the simulations for the absorption of CO2 in aqueous sodium hydroxide solution. Simulation predictions were in good agreement with the experimental data for different values of gas flow rates. The modeling predictions indicate that the removal of CO2 increased with increasing inlet liquid flow rate and increasing solvent temperature, by contrast, increase in inlet gas flow rate has negative effect.

Ultraefficient reduced model for countercurrent two-layer flows

Abstract: A reduced two-phase model suitable for industrial uptake is introduced to predict the onset of flow reversal in falling films under countercurrent flow. Analysis of spatiotemporal stability and wave topology shows that vortex distribution plays a crucial role in the incipience of flow reversal.

Numerical Simulation of Magnetic Nanoparticles Injection into Two–phase Flow in a Porous Medium

Abstract: In this paper, the problem of magnetic nanoparticles injection into a water–oil two–phase flow under an external permanent magnetic field is investigated. The mathematical model of the problem under consideration has been developed. We treat the water-nanoparticles suspension as a miscible mixture while it is immiscible with the oil phase. The magnetized phase pressure includes an additional pressure term with the conventional thermodynamic pressure. The countercurrent imbibition flow problem is taken as an example. Physical variables including water–nanoparticles suspension saturation, nanoparticles concentration, and pore wall/throat deposited nanoparticles are investigated under the influence of the magnetic field.

Prediction of Countercurrent Flow Limitation and Its Uncertainty in Horizontal and Slightly Inclined Pipes

Abstract: We proposed prediction methods for countercurrent flow limitation (CCFL) in horizontal and slightly inclined pipes with one-dimensional (1-D) computations and uncertainty of computed CCFL. In this ...

Energy feature of a multi-flow column flotation process

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.

Countercurrent liquid-liquid extraction on paper.

Abstract: Proof-of-concept is shown for two-phase countercurrent flow on paper. The device consists of two paper layers, one of which has been modified with a sizing agent to be hydrophobic. The layers exhibit different wetting behavior for water and octanol. Both phases dominate wetting in one of the layers and can be made to move in different directions along the interface to achieve liquid-liquid extraction.

Device and method for counter-current heat exchange between a fluid and heat storage particles

Abstract: The present invention relates to a device for heat exchange between a fluid and heat storage particles (6). The exchange system comprises two volumes (2, 3) for storing the particles, and an exchange zone (4) in which the fluid (F) and said heat storage particles (6) flow in counter-current.

Reformer tube having a structured catalyst and improved heat balance

Abstract: A reformer tube for producing synthesis gas by steam reforming of hydrocarbon- containing feed gases, in which a structured stream reforming catalyst is used, is proposed. According to the invention, a heat exchanger tube is arranged in the interior of the structured catalyst, with the feed gas stream flowing firstly through the structured catalyst and subsequently in countercurrent through the heat exchanger tube. This improves the heat exchange between the synthesis gas product stream and the structured catalyst and the feed gas stream flowing through it, especially in the radial direction.

Assistant water cooling refrigerating system with vertical countercurrent direct contact condensation heat exchanger

Abstract: The invention discloses an assistant water cooling refrigerating system with a vertical countercurrent direct contact condensation heat exchanger. The assistant water cooling refrigerating system comprises a refrigeration compressor, an oil separator, an assistant water cooling heat exchanger, a first solenoid valve, a second solenoid valve, a third solenoid valve, a vertical countercurrent direct contact condensation heat exchanger, a fourth solenoid valve, a throttling valve, a liquid pump, an evaporator, a shell, liquid baffle plates and nozzles, wherein the vertical countercurrent direct contact condensation heat exchanger consists of the shell, the liquid baffle plates and the nozzles; the inlets of the nozzles are connected with a liquid supply tube and are uniformly distributed at the upper part of the shell; outlets of the nozzles face downwards; the liquid baffle plates are welded inside the shell at equal intervals; the outlet of the refrigeration compressor is divided into two paths through the oil separator; one path is connected with a shell inlet of the assistant water cooling heat exchanger through the first solenoid valve; the other path is connected with a gas inlet of the vertical countercurrent direct contact condensation heat exchanger through the third solenoid valve. By adopting the assistant water cooling refrigerating system, the exhaust temperature of the refrigeration compressor can be effectively reduced, the pressure ratio can be reduced, the refrigeration capacity of the refrigeration system can be increased, the performance of the refrigeration system can be improved, the structure is simple, the operation is convenient, the environment can be protected, and the energy can be saved.

Cocurrent and countercurrent extraction based on a novel three-dimensional vortex microextractor

Abstract: A single-stage cocurrent arrangement was described based on a three-dimensional (3-D) vortex microextractor using the vortex effect, and the 3-D microextractor was further modified to establish a countercurrent arrangement without any interstage pumps or check valves. The 3-D vortex microextractor mainly composed of an inlet channel, two circular chambers, a slender cylindrical connection channel, and an outlet channel. In both cocurrent and countercurrent operations, the flow pattern and extraction performance were investigated and analyzed. In the cocurrent arrangement, the hydraulics experiment results demonstrated that the 3-D vortex microextractor could passively and effectively produce droplets even at high fluxes of the dispersed phase. The extraction experiment results confirmed that the vortex effect of the 3-D microextractor could enhance the shear force and facilitate the production of droplets, consequently enhancing the extraction efficiency. Furthermore, it was experimentally proved that the countercurrent arrangement could be realized relying on the modified 3-D microextractor and alternatively pulsed feeding of both phases.

System and method for the crossflow exchange of heat between a fluid and heat storage particles

Abstract: The present invention relates to a system and a method for exchanging heat between a fluid (F) and heat storage particles (3). The exchange system comprises an exchange zone (2) in which the fluid (F) and the heat storage particles in a fluidized bed flow as a countercurrent flow and a cross flow. The invention also relates to a compressed gas energy storage and restoration system and method using the heat exchange system.

Study of the two-stage gasification process of pulverized coal with a combined countercurrent and concurrent flow system

Abstract: The paper presents a numerical study of an advanced two-stage gasifier with a combined countercurrent and concurrent flow pattern and dry fuel feed system EAGLE. The Reynolds Stress model was used for the numerical simulation of turbulent flow. We have conducted studies on the influence of upper burner’s inclination angle on heat and mass transfer processes in the gasifier as well as on coal conversion. It is shown that the increase in the upper burner’s inclination angle in the horizontal plane allows intensifying the process of two-stage gasification.

Vortex heat exchange element

Abstract: FIELD: heating equipmentSUBSTANCE: invention relates to the heating equipment, and can be used in heat exchangers, used in various branches of engineering, in particular in the reactor building gas-turbine installations regenerative heat exchangers In the vortex heat exchanging element containing coaxially arranged one inside the other heat exchange cylindrical tubes of larger diameter and the inner tube with cylindrical surfaces, at that the larger diameter tube is divided into sections, inside each of the tubes installed at least, two swirlers of the same or different types, wherein one swirler is at the entrance to the site, and the second is at a distance between them, determined by the swirling flow rotational motion complete attenuation at full thermal load, moreover, heat carriers inputs into each of the pipe sections of larger diameter and the inner pipe are made either from the same side, or from opposite sides with respect to the flow movement, providing both countercurrent and straight-through flow patterns of the heat carriers in the element, at that, the inner pipe with cylindrical surfaces is made of bimetal, wherein, the inner pipe surface material from the hot heat carrier side has a thermal conductivity coefficient in 20–25 times higher than the inner pipe surface material from the cold heat carrier side, wherein, on the cylindrical pipe of a larger diameter, along the outer surface, in each section determined by the swirling flow rotational motion complete attenuation at full thermal load, the fins packages are made, wherein, the distance between the ribs in each package decreases, in addition on each edge of the package vertical surface, located on a cylindrical tube of larger diameter, the helical grooves are made, wherein, the tangent helical groove direction on the adjacent rib opposite vertical surface has a counterclockwise direction, the helical grooves curvature is made along the cycloid line as a brachistichrone, and the cavities look like a dovetailEFFECT: enabling the ribs package heat transfer capacity constancy in the presence of the contamination solid particles in the heated heat carrier1 cl, 7 dwg

Method for separating materials by means of an extractive distillation process

Abstract: The invention relates to a method for separating a mixture of materials A and B by means of an extractive distillation process using an extraction agent with a higher affinity for B than for A. A feed flow containing A and B is conducted in countercurrent with the extraction agent in a column (3), wherein an A-containing head fraction (6) and a B- and extraction agent-containing liquid fraction are obtained. The liquid fraction is collected on a collection base (7) and heated and partially evaporated in a first indirect heat exchanger (9). The resulting steam is released into the column (3), and a non-evaporated portion of the liquid fraction is collected as a bottom fraction (11) in the bottom of the column. The bottom fraction is heated and partially evaporated in a second indirect heat exchanger (13) and a third indirect heat exchanger (14) one after the other. The resulting steam is at least partly released into the column. The bottom fraction is separated into a B-containing fraction (33) and an extraction agent fraction in a stripper (32). The extraction agent fraction is used as a heating medium for the second heat exchanger, wherein a partially cooled extraction agent fraction is obtained. An external heating medium is used for the third heat exchanger, and the partially cooled extraction agent fraction is used as a heating medium for the first heat exchanger (9).

Theoretical study of dynamic countercurrent cyclic extraction processes for the separation and concentration of components of a liquid mixture

Abstract: Some results of theoretical studies on different dynamic countercurrent cyclic extraction variants and the effect of principal process parameters on the efficiency of separation for liquid mixture components have been given. The studies are based on a modified model of the equilibrium stages. It has been established that the proposed extraction mode enables the concentration of target mixture components with their simultaneous separation.