(477b) Implementation of a Customized Gas-Separation Membrane Model into Commercial Flowsheeting Software to Simulate a Hybrid CO2 Removal Process for Oxidative Coupling of Methane

The oxidative coupling of methane (OCM) is a promising path for converting methane into ethylene (ethene). Hence, OCM offers an alternative route to produce basic chemicals from natural gas or biogas instead of oil. As a main by-product of the reaction, carbon dioxide must be removed in a downstream CO₂ capture section. It is typically removed by energy intensive amine-based absorption desorption systems. The focus of this contribution is (1) to design and simulate alternative hybrid systems for carbon dioxide removal using dense membranes for gas separation and (2) to integrate models implemented in the free, web-based modeling environment MOSAIC^[1,2] into commercial simulation software such as Aspen Plus®.

A model for the membrane module based on solution diffusion permeation and free-volume theory is implemented in MOSAIC. The model has previously shown good agreement with experimental data from a pilot plant in Berlin University of Technology. Code is automatically generated via MathML based on the documentation in MOSAIC for subsequent solution in Aspen Custom Modeler®. For other domain specific languages and tools, e.g. gPROMS®, MATLAB, Modelica, and programming languages such as FORTRAN, C++, Python, etc. code can also be generated in MOSAIC without further user input.  In this contribution, the membrane module is integrated into Aspen Plus® for the simulation of a hybrid separation system aiming at 97% of CO₂ removal.

Multiple flowsheets consisting of an upstream membrane cascade section and a downstream absorption desorption section are simulated and analyzed. Absorption and desorption columns are designed using rate-based calculations with an Electrolyte NRTL model. Utility consumption and equipment costs are evaluated using Aspen Economic Analyzer®.  It is shown that the specific energy consumption per kilogram of removed CO₂ can be reduced with acceptable product loss by the use of the hybrid process. The possibility to export models from MOSAIC to Aspen Plus® allows for the easy implementation of customized unit operations into commercial flowsheeting software, while modeling in a LaTeX-based documentation style.

The modeling procedure and workflow for the implementation will be presented in detail during the presentation. Documentation-based modeling is discussed and the reusability of hence developed models across platforms and languages is highlighted.

1) www.mosaic-modeling.de, last accessed 05/11/2015

2) S. Kuntsche, H. Arellano-Garcia and G. Wozny: MOSAIC, an environment for web-based modeling in the documentation level, Computer Aided Chemical Engineering, 29:1140-1144, 2011