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.

Bubble size analysis in a two-phase countercurrent flow in the narrow rectangular column

Abstract: The flow of bubbles in a two-phase system has great implications in chemical, petrochemical, and biochemical applications. This work enunciates the measurement of bubble size distribution and bubble aspect ratio in three-different axial zones in the countercurrent flow mode with a gas and liquid velocity range of 0.044–0.321 and 0.019–0.058 m/s, respectively. Bubble size is measured by the photographic technique. The bubble aspect ratio and bubble size distribution results reveal that the impact of gas and liquid velocities is significant on the Sauter mean bubble size. The Sauter mean bubble size increases as the gas velocity increases, whereas it decreases with the liquid velocity. The Sauter mean bubble diameter ranges from 2.65 to 6.16 mm. The distribution of bubble sizes follows the LogLogistic probability density function. In addition, a correlation is also proposed for the interpretation of bubble diameter in terms of Reynolds number and Froude number. The bubble aspect ratio changes with axial zones and gas and liquid velocities. Experiments reveal that the bubble aspect increases with liquid velocity while decreasing with gas velocity and axial zones. The bubble aspect ratio correlations are developed in terms of Eötvös and Reynolds numbers. The present results will be helpful for the process intensification of bubble-aided two-phase flow applications.

Optimal plate aspect ratio for the best performance of the enrichment of heavy water in thermal-diffusion columns of a countercurrent-flow frazier scheme

Abstract: The effect of plate aspect ratio on the performance of enrichment of heavy water in thermal-diffusion columns of a countercurrent-flow Frazier scheme was investigated. The equation for the optimal plate aspect ratios and the corresponding best performance were derived. Considerable improvement in performance is obtained when thermal-diffusion columns are operated at the optimal plate aspect ratio. Further improvement can be achieved if the scheme is connected and operated in countercurrent flow, instead of concurrent flow.

Continuous countercurrent differential extraction method and continuous countercurrent differential extraction device

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.

Mass-transfer in a rotating packed-bed with countercurrent gas-liquid flow

Abstract: Preliminary theoretical and experimental results indicate that the rotary packed-bed is a promising device for gas-liquid-solid contacting. Its application in gas-liquid operations on a large scale and gas-liquid-solid reactions on laboratory scale are expected. Further results in characterizing the device will be forthcoming

Membrane fuel cell countercurrent-fed with non-humidified air

Abstract: The present invention describes a membrane fuel cell capable of operating in a stable fashion at high currently density under dry reactant gas feed at near-atmospheric pressure. This result is obtained by employing internal porous gas distributors, such as three-dimensional reticulated materials, sintered materials, juxtaposed meshes or expanded sheets, and at the same time by countercurrent-feeding the gas reactants, preferably ambient air, from the bottom. In one preferred alternative liquid water is injected from the bottom into the air feed: with these operating conditions, an extremely simplified stable functioning is obtained, since the air and water flow-rates, adjusted as requested for the maximum nominal electrical output, are kept unvaried even at low or zero output conditions without the cell membrane undergoing dehydration.