Enhanced Light Alkane Dehydrogenation via Coupling with Chemical Looping

Catalytic dehydrogenation reactions for light alkane upgrading are limited by equilibrium at most industrially relevant temperatures. These thermodynamic limitations can be mitigated via removal of hydrogen using reactive separation techniques. Typical reactive separation techniques include the use of hydrogen permeable membranes1, selective hydrogen combustion2, and selective hydrogen adsorption3. We propose a novel reactive separation technique for the removal of hydrogen during alkane dehydrogenation based on chemical looping. In our proposed process a dehydrogenation reactor is coupled with a chemical looping reactor for selective hydrogen oxidation and a high temperature water adsorbent to remove the produced water. In our initial work we demonstrate the viability of this concept for use with methane dehydroaromatization by a combination of single stage dehydroaromatization experiments and metal oxide redox experiments in quartz tube microreactors4. In our current work we apply a newly constructed novel microreactor, capable of recirculating heated gas through 3 separate reactors as well as intermittently regenerating catalyst beds and re-oxidizing metal oxide beds, to investigate

coupling methane dehydroaromatization to chemical looping in more realistic process conditions. In the future we intend to apply this unique design to other dehydrogenation reactions including propane dehydrogenation, ethane dehydrogenation, and methane dehydrogenation to ethylene.

References

[1] R. W. Borry; E. C. Lu; Y.H. Kim; E. Iglesia, Stud. Surf. Sci. Catal., 119 (1998), 403.

[2] J.G. Tsikoyiannis; D.L. Stern; R.K. Grasselli, J. Catal., 184 (1999) 77.

[3] A. Kumar; K. Song; L. Liu; Y. Han; A. Bhan, Angew. Chem., (2018). [4] C. Brady; B. Murphy; B. Xu, ACS Catal., 7 (2017) 3924.