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Mass transfer studies on the dehydration of supercritical carbon dioxide using dense polymeric membranes

Authors :
Sybrand J. Metz
Zandrie Borneman
Henk Miedema
Andrew Shamu
Kitty Nijmeijer
Membrane Materials and Processes
Source :
Separation and Purification Technology, 209, 229-237, Separation and Purification Technology, 209, 229-237. Elsevier
Publication Year :
2019

Abstract

Continuous drying processes using supercritical CO2 (scCO2) as a water extraction agent require 24/7 operational dehydration units for scCO2 regeneration. Dehydration units using dense polymeric membranes are considered a cost effective, sustainable alternative to the current zeolite-based units. The focus of previous studies on the membrane-based dehydration of scCO2 was always on the membrane itself whereas boundary layer effects, e.g., concentration polarization, were not taken into account. To quantify the boundary layer effects, simulations were performed using three different membrane materials: SPEEK, Nafion® 117, and PEBAX® 1074. Process conditions during the simulations ranged from 8.0 to 18.0 MPa and 40 to 100 °C. Even though the three types of membranes examined differ in their H2O permeability and H2O over CO2 selectivity, in all cases 80% of the total mass-transfer resistance can be assigned to concentration polarization effects, making it the dominant parameter for water transport. Despite high but differing intrinsic water permeabilities of all three membranes materials, the H2O transport, thus H2O flux through the membrane is significantly reduced by concentration polarization down to similar levels. This makes it necessary to use larger membrane areas, that result in higher CO2 fluxes. As a consequence, material selection is predominantly based on the ability to reject CO2. Optimization of process conditions other than membrane material is briefly discussed.

Details

Language :
English
ISSN :
13835866
Volume :
209
Database :
OpenAIRE
Journal :
Separation and Purification Technology
Accession number :
edsair.doi.dedup.....b3274107863cae9480cb090745b98c02
Full Text :
https://doi.org/10.1016/j.seppur.2018.07.042