Modeling and simulation of a hybrid separation process for the carbon dioxide removal of the oxidative coupling of methane process

The oxidative coupling of methane (OCM) is a promising alternative for the oil- based production of olefins. The aim is to convert methane- containing natural gas catalytically to ethylene and open up a new feedstock for olefins and further organic synthesis products [1], [2]. The whole process is designed modular and built up in a miniplant to investigate different new approaches. For realization in a short time period, but in a more efficient way, the entire process is divided into three units: reaction unit, purification unit and separation unit, which are designed simultaneously. Particular requirements for process conditions on the transitions had to be defined and were done by laboratory screenings and literature study. Due to the novel process design strategy, downstream process conditions affect the design specification for the catalyst and the reaction unit. In the article the purification section is discussed particular and a novel hybrid separation process for the CO2 removal is presented. An efficient and modern carbon dioxide separation process of a membrane and an amine unit was developed. The membrane unit has been modeled with Aspen Custom Modeler (R) (ACM), and was integrated in the Aspen Plus (R) process simulation. The amine unit was modeled with a rate- based absorption model, including an electrolyte NRTL approach [3] and concentration- based reaction kinetics [4]. The simulation results of the conventional amine process, the single membrane unit and the improved novel hybrid process are presented in this paper.