# Modeling acid gas competitive facilitated transport on a spinning disk liquid membrane

## Description

The data that follows was used in the article "Modeling acid gas competitive facilitated transport on a spinning disk liquid membrane" published in the Journal of Memrane Science in 2021. It presents a model of a spinning disk liquid membrane used to separate acid gases - hydrogen sulfide from carbon dioxide. Simulations of the model shows that acid gases separation using a spinning disk liquid membrane is feasible, and has the potential to attain a high performance in both permeability and permselectivity. The data used in the related article consists of 3 files: - SDLM_matlab_program: this is a matlab source file containing the program used to simulate the model described in the article. - SDLM_model_notes: this is a pdf file that shows the elaboration of the equations and construction of the model in bigger detail than the article. - SDLM_tables_and_graphics: this is an excel file with data used to calculate the liquid solution properties, and tables that contains data of several simulations, which were used to build some of the graphics in the article.

## Files

## Steps to reproduce

The matlab program used to simulate the model does not contain any kind of user interface. Input data for a particular simulation must be changed directly in the program. The program available here contains the default values, used as base case for most simulations in the article. Some of the details of how the program works is described below: To solve the model’s algebraic and partial differential equations, a customized function named “SERXN_H2S” was developed in Matlab, and solved using its subroutine pdpe. Since there is axial symmetry, there is no need for a three dimensional cylindrical grid. Instead, in a cross-section of the liquid film (Fig. 3), a rectangular grid of over 100 points in the radial direction and 24 points in the vertical direction is used. In the former, points are concentrated near the entrance (r=1), while in the latter, they are distributed closer to the bottom (z=0) and top (z=1) of the film. At each step of the integration of equations 41 to 43 (inside function pde_eq), the values of cBC and cS are calculated and de-convoluted using equations 37–40, ultimately giving the concentrations of bicarbonate, carbonate, and hydrogen sulfide. Similarly, inside the boundary condition function pde_bc, from the calculated values of cH2S and cBC at the top and bottom boundaries, the values of the ion concentrations are de-convoluted. The tolerance used in the integration is stricter than 1.E-8. To ensure that there are no accumulated errors, the mass balances over the liquid film are checked at the end of the integration. Liquid recirculation is simulated using the disk’s exit concentrations at the entrance. This procedure is repeated in a loop (approximately 5 times) until the exit concentration converges.