Multi-scale modelling of OSN batch concentration with spiral-wound membrane modules using OSN Designer

Abstract

Three commercial spiral-wound membrane modules of different sizes, from 1.8"x12" to 4.0"x40", are used to concentrate a solution of sucrose octaacetate in ethyl acetate under different operating conditions. A mathematical model to describe the batch concentration process is developed, based on a combination of the classical solution diffusion membrane transport model and the film theory, to account for the mass transfer effects. The model was implemented using the "OSN Designer" software tool. The membrane transport model parameters as well as all parameters in the pressure drop and mass transfer correlations for the spiral-wound modules were obtained from regression on a limited number of experimental data at steady state conditions. Excellent agreement was found between the experimental and multi-scale modelling performance data under various operating conditions. The results illustrate that the performance of a large scale batch concentration process with spiral-wound membrane modules can be predicted based on laboratory crossflow flat sheet test data when the fluid dynamics and mass transfer characteristics in the module, and the necessary channel geometry are known. In addition, the effects of concentration polarisation, pressure drop through feed and permeate channels, and thermodynamic non-ideality of the solution at large scale batch concentration are also investigated.2

Nanofiltration membranes and processes: A review of research trends over the past decade

“…For example, the pores of the membrane may shrink or swell depending on the interaction with the solvent [33]. There have been some attempts to model OSN systems (such as OSN designer used in conjunction with MATLAB [34]) but these are still in their infancy and need to be improved to take into account physical reality such as fouling etc. Thus, nanofiltration modelling is inherently coupled to measurement technology and until there is a step change in measurement at the nanoscale, interest in modelling nanofiltration membranes is likely to amble along or decline yet further.…”

Towards sustainable ultrafast molecular-separation membranes: From conventional polymers to emerging materials

“…Other than intrinsic membrane properties, the operational and external factors that affect mass transfer across a membrane include the pressure difference across the membrane (ΔP), concentration polarization, swelling of the membrane, operating temperature, feed solution flow rate, the interaction between solvent and solute, and the interaction between solute and membrane [7][8][9]11,[78][79][80][81][102][103][104][105]. The latter four parameters are seldom investigated.…”

“…It remains nearly impossible to increase permeate purity by several orders of magnitude in real-life applications, where cross-flow separation mode is commonly deployed. This is ascribed to the limitation of feed solution flow-rate, pressure drop and concentration polarization in the membrane modules [78][79][80][81]. The energy consumption of separation processes, particularly the desalination of sea water, can be reduced using membranes with permeances of up to 10 L m −2 h −1 bar −1 [1,78,[82][83][84].…”

“…The membrane surface areas of conventional UF or NF membrane modules (approximately 40 m 2 for an 8.0″ × 40″ size module) are too large to maintain a high permeate solution flow-rate. This is due to the complicated mass transfer phenomenon within the module [78][79][80][81], pressure drop and concentration polarization. Reducing the membrane surface area not only decreases the capital cost of membrane systems but also benefits mass transfer in the membrane module [79].…”

Iterative peptide synthesis in membrane cascades: Untangling operational decisions

“…Membrane enhanced peptide synthesis (MEPS) addresses this purification challenge with the membrane process, which has been used for various applications (Cseri et al, 2016;Dong et al, 2017;Fodi et al, 2017;Gao et al, 2017;Shi et al, 2016). The valuable peptide is grown attached to a soluble anchor (Castro et al, 2017;Gravert and Janda, 1997) in the liquid phase with standard Fmoc chemistry.…”