(732e) Efficient Chemicals Production Via Chemical Looping

This project develops the chemical looping (CL) technology into a general process intensification for natural gas upgrading to commodity chemicals. Nonoxidative upgrading of methane dehydroaromatization (MDA) to aromatics is often limited by thermodynamics, which could be alleviated by CL from selective oxidation of H2 product and H2O adsorption on the molecular sieve. Silica-encapsulated Fe2O3 is implemented for the CL, and a silica shell can inhibit larger molecules of aromatics from diffusing to the Fe2O3 surface, enhancing overall MDA performance by selective H2 combustion. The developed system provides high methane conversion and aromatic yield of ~50% and ~35%, respectively, in a recirculating mode for 4 hours. In addition, we develop an optimization and control relevant dynamic model for the modular integrated process, consisting of MDA and CL by using a restricted set of process information. A novel iterative modelling framework integrating active learning principles with state estimation techniques is proposed. The proposed approach will allow us to learn the integrated process model iteratively through experimentation even when the process data is limited. For further development of other natural gases (ethane or propane), In, Ga, or Mn-based zeolites with different Si/Al and metal/Al ratios are synthesized and used to catalyze alkane dehydrogenation. A novel type of Mn supported on zeolite are found to have high reaction activity and high selectivity. The reaction process and potential working mechanism are investigated using in-situ Raman and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).