(10a) Process Optimization Using Perturbation Expansion Solutions for Membrane Gas Separation Modules

Simulation and optimization of hybrid membrane gas separation processes, such as those proposed for carbon capture, require high fidelity module performance simulations. Unfortunately, these simulations require iterative solution techniques which can be sensitive to the initial solution guess and thus require extensive iteration (i.e., computational time) or fail to converge.

Perturbation solutions to the isothermal, constant transport property, multi-component cross-flow and counter-current flow performance equations are presented. Predictions from the direct, non-iterative solution are compared to solutions obtained using numerical approximations. Excellent agreement is found in all cases even for systems with broad ranges of recovery for feed gas components. The results also are excellent initial guesses for simulations that account for module non-idealities.

The use of these solutions in optimizing staged membrane systems is discussed. The perturbation solution can dramatically speed up optimization and help identify unfeasible configurations.