Over the past decade, a great deal of research has been devoted to membrane contactors (MBC) for CO2 absorption in natural gas sweetening applications. One key advantage of MBC over conventional absorption towers is their large intensification potential. In this work, the MBC mathematical model presented in Quek et al. [1], is used to carry out global sensitivity analysis and process optimization studies using the gPROMS ProcessBuilder. Global sensitivity analysis is used to determine the membrane characteristics and operating conditions that have the largest impact on CO2 removal performance and costs. Next, the standalone MBC unit model is integrated with gPROMS ProcessBuilder standard unit operations model libraries to model an MBC-based flowsheet of a semi-lean process for natural gas sweetening (Fig. 1). This flowsheet is optimized with the objective of minimizing the annualized cost, subject to a given CO2 specification. The optimization is carried out by applying a simple direct search in Matlab using the gO:Matlab interface. Fig. 1. Semi-lean MBC process flowsheet.References: [1] V. C. Quek, N. Shah, and B. Chachuat, Modeling for design and operation of high-pressure membrane contactors in natural gas sweetening, Chem. Eng. Res. Des. 132:1005-1019, 2018.
