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.

Volatile organic component removal by membrane separation using countercurrent sweep gas

Abstract: There is disclosed an improvement to membrane-based separation processes for the removal of condensable organic components from fluid feed steams, comprising the use of a sweep stream 30 on the permeate side of the membrane 55 in a membrane module 25, said sweep stream being arranged to flow countercurrent to the fluid feed stream 14.

Performance Analysis of Aluminum and Graphite Foam Heat Exchangers Under Countercurrent Arrangement

Abstract: Due to the increasing power requirement and the limited available space in the vehicles, a countercurrent heat exchanger (HEX) is proposed for the position on the roof of the vehicle compartment. Furthermore, a new material, graphite foam with high thermal conductivity and low density, is a potential material for HEXs in vehicles. In order to evaluate the performance of the graphite foam HEX, the CFD computational fluid dynamics (CFD) approach is applied in a comparative study between the graphite foam and the aluminum HEXs under countercurrent flow condition. The analysis is conducted for the thermal performance (heat transfer coefficient) and the pressure loss. The simulation results show that the graphite foam HEX proves higher thermal performance than the aluminum HEX. However, due to the high pressure loss in the graphite foam HEX, the coefficient of performance in the graphite foam HEX is much lower than that of the aluminum HEX. A specific case study is carried out to evaluate the performance of gr...

Theoretical Investigation of Nonlinear-Diffusion Countercurrent Imbibition for Porous Medium with Micro-/Nanopores

Abstract: Countercurrent imbibition is an important oil recovery mechanism in tight reservoir development. For tight oil reservoirs with hydraulic fractures and natural fractures, the injected fluid imbibes into a tight matrix from the fracture surface while crude oil flows reversely into the fracture during the process of liquid injection and soaking. Based on the traditional imbibition model, this paper proposes a countercurrent imbibition extension model for porous medium with micro-/nanopores, considering the early superdiffusion phenomenon under low water saturation. The reliability of this proposed model is further verified through experimental imbibition data and compared with the classical imbibition model. This model can obtain the dynamic evolution process of the imbibition saturation profile and quantify the countercurrent imbibition distance (imbibition range). The sensitivity analysis is then conducted, including the imbibition time, core length, characteristic parameters of relative permeability, characteristic parameters of capillary pressure, oil viscosity, and permeability. The results demonstrate that the countercurrent imbibition process can be divided into three stages: the superdiffusion stage (faster than t0.5), transition stage, and subdiffusion stage (slower than t0.5). Two key parameters, the critical imbibition saturation and its corresponding critical imbibition time, can be obtained through this model, which are significant to establishing reasonable soaking time for achieving higher oil recovery. This research improves the understanding of the countercurrent imbibition process, which explores the efficient development of water injection for tight oil reservoirs with micro-/nanopores.