Mass Transfer Studies in Pulsed Sieve Plate Extraction Column for the Removal of Tributyl Phosphate from Aqueous Nitric Acid

Abstract

Removal of a saturated amount of tributyl phosphate (TBP) from a nuclear reprocessing aqueous waste stream is very important as far as economy of process as well as waste disposal is concerned. The present research work describes the detailed mass transfer studies for the removal of TBP from aqueous stream in a geometrically optimized pulsed sieve plate extraction column (PSPEC). The original industrial system, viz., 0.3 M nitric acid–TBP–normal paraffinic hydrocarbon (NPH), was used for the mass transfer studies. The effect of operating parameters such as continuous to dispersed phase velocity ratio and pulsed velocity on the volumetric mass transfer coefficient was investigated. The effect of operating parameters on the variation in axial concentration and holdup profile is also studied to evaluate the dynamic operation of the column for the attainment of steady state. The experimental results indicate that pulse velocity has a strong effect on the volumetric mass transfer coefficient, while the effect of the continuous phase flow rate is greater than the effect of the dispersed phase flow rate.

CFD Simulation of Two-Phase Flow in a Hybrid Pulsed Sieve-Plate Solvent Extraction Column: Prediction of Holdup and Axial-dispersion Coefficients

“…Hydrodynamic parameters, especially holdup, are important to determine the column throughput, while mass transfer parameters including axial dispersion coefficients are important to determine separation efficiency [11,12] . Researchers have investigated the hydrodynamic [13][14][15][16] and mass transfer performance [15,17,18] of standard pulsed sieve plate columns. Additionally experiments have been performed to test the hydrodynamic [9] and mass transfer [10] performance of the two types of novel ceramic internals.…”

Axial Dispersion and Mass Transfer of a Pulsed Solvent Extraction Column with Novel Ceramic Internals

“…Hydrodynamic parameters are important to determine the column throughput, while mass transfer is the key parameter to determine separation efficiency 9,10 . Recent studies have investigated hydrodynamic [11][12][13][14] and mass transfer performance 13,15,16 of pulsed sieve plate columns. According to Yadav et al 8 , many researchers interpret the mass transfer data without taking into account the effect of axial dispersion, which according to Nabli et al 17 would cause over-prediction of the separation efficiency by up to 30%.…”

“…Yadav and Patwardhan gave a thorough summary of previous work and a comparison of different correlations about design aspects of pulsed sieve plate column including drop size, holdup, flooding point, and mass transfer, among which the first three can be classified into hydrodynamic parameters. Hydrodynamic parameters are important for determining the column throughput, while mass transfer is the key parameter determining separation efficiency. , Recent studies have investigated hydrodynamic − and mass-transfer performance ,, of pulsed sieve plate columns. According to Yadav and Patwardhan, many researchers interpret the mass-transfer data without taking into account the effect of axial dispersion, which according to Aoun Nabli et al would cause overprediction of the separation efficiency by up to 30%.…”

Two-Stage Feedback Miniextractor with High-Throughput via Selective Dimension Scale-Out

“…Over the past decades, microextractors have attained full development owing to properties including small volume, high efficiency, low fabrication cost, safety, and better controllability. − These advantages overcome problems emerging on traditional extraction devices such as pulsed extraction columns, , mixer-settlers, , and centrifugal extractors , with respect to a large factory area, large volume of solvent consumption, high energy consumption, long residence time, and high costs of fabrication and control. , …”