Performance Evaluation of Different Reactor Concepts for the Oxidative Coupling of Methane on Miniplant Scale

In this study, three different reactor concepts for the oxidative coupling of methane (OCM) reaction are examined at the miniplant scale. Their performance and response to variations in key process parameters, such as temperature and gas hourly space velocity (GHSV), are evaluated over a wide range. In addition to the conventional Packed Bed Reactor (PBR), Packed Bed Membrane Reactor (PBMR), and Chemical Looping Reactor (CLR) approaches were tested. The PBMR was realized with a porous ceramic α-Alumina membrane as air/O2 distributor. The CLR was operated in a poly-cyclic operation. Similarities of the different reactor concepts as well as layout-immanent differences with regard to changes in reaction conditions could be identified and advantages and disadvantages of the processes highlighted. The results show that C2 selectivity can be improved by both PBMR and CLR in comparison to conventional PBR, possibly reducing cost-intensive downstream units. While a PBMR can slightly improve selectivity (23%) while keeping the same conversion compared to a PBR, the use of a CLR allows for achieving exceptionally high selectivities of up to 90%. In order to address the low conversion, CLR tests were carried out with an additional O2 carrier material, which led to a significant improvement in terms of C2 yield. In addition to an evaluation and comparison of the different reactor concepts, the findings at the miniplant scale provide estimates of their potential use and scalability.