Membrane separation process for CO2 capture from mixed gases using TR and XTR hollow fiber membranes: Process modeling and experiments

Abstract

Numerous membrane models have been developed and tested for the simulation of membrane processes. However, these models are often either simplified or only validated with a narrow range of experimental data. For the model-based process design of membrane systems it is necessary to have a validated and accurate model which is accurate for the range of possible operating conditions under consideration. Hence, in this study a modeling framework is developed for hollow fiber membranes which can be adjusted systematically to accurately predict the performance of a given membrane. Mixed-gas (CO2/O2/N2 and CO2/N2) separation experiments are carried out over a range of different feed conditions to evaluate membrane performance and to provide reliable measurements of gas permeance. In particular the feed pressure (1–4bar), permeate pressure (0.1–0.5bar) and feed flow rates (0.096–0.4Nm3/h) are varied in these experiments (the ranges specified in brackets). Interpolation of these measured permeance allows for the accurate prediction of membrane performance at any conditions inside the measured range. A tanks-in-series modeling approach is employed here where the number of tanks (used to represent the membrane behavior in a numerical formulation) can be adjusted to calibrate and fit the membrane model to experimental results. For the membranes tested in this study it is found that using a relatively small number of tanks both minimizes the difference between model and experimental results and reduces the numerical complexity in the membrane model.