(186k) Scale up Design Optimization of a Membrane Module for Gas Separation

This work introduces the development of dynamic simulation model of a gas separation membrane by deriving a mass balance and energy balance equations (Ko, 2017a) and a mathematical based scale up design method. The adopted membrane module is a hollow-fiber membrane with counter-current flow to recover methane from coalbed methane (CBM). The bore sides within the fibers receive the feed flow and emit the retentate flow, which is the purified CBM gas. The permeate flow from the shell side is discharged as a waste stream. The simulation results agree well with lab scale experimental data provided by a membrane vendor company in Korea. To perform the scale up design of membrane modules, the number of fibers as an integer variable should be determined properly using an optimization solver. But if the integer variable is included in the optimization problem, the computation load is too big for the problem to be solved reasonably. Hence this study introduces the new optimization method to efficiently solve the problem (Ko, 2017b), and the scale up design optimizations were successfully performed up to a commercial plant scale (500Nm³/h of feed flow rate). As a conclusion, the optimal design conditions, i.e., the effective length, the number of fibers, and the inside shell diameter, are easily obtained from a small laboratory scale to a large commercial plant scale by employing the developed optimization algorithm and simulation model.