Methane-to-aromatics in a gas recycle methane reactor/hydrogen membrane separator

• Published in: Catalysis today 2021-04, Vol.365, p.80-87
• Main Authors: Sakbodin, Mann, Schulman, Emily, Pan, Ying, Wachsman, Eric D., Liu, Dongxia
• Format: Article
• Language: English
• Subjects: Direct non-oxidative methane conversion; Fe/SiO2 catalyst; Hydrogen-permeable membrane; Natural gas upgrading; SrCe0.8Zr0.2O3-δ ceramic
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2020.06.028

[Display omitted] •CH4 reactor/H2 separator recycle system is studied for non-oxidative CH4 conversion.•CH4 reactor/H2 separator recycle circumvents thermodynamic limit in CH4 reaction.•High purity of H2 product and high performance membrane separator are achieved.•>90 % selectivity and >50 % yield in aromatic product are achieved in recycle system.•Economic feasibility of CH4 reactor/H2 separator recycle system is simulated. Direct non-oxidative methane conversion (DNMC) is one of the most promising options to convert methane (CH4) in natural gas in remote extraction sites to liquid aromatics, which is easier to transport compared to CH4 gas. The main constraint of the DNMC is low CH4 conversion, and thus aromatics product yield due to thermodynamic limitation. This work reports a gas recycle CH4 reactor/hydrogen (H2) membrane separator to achieve high CH4 conversion and aromatics yield by circumventing the thermodynamic limitation. The DNMC took place over an iron/silica (Fe/SiO2) catalyst in a packed-bed reactor to produce C2 (i.e. ethane, ethylene and acetylene) and aromatics, along with reaction product H2. The product stream passed through a condenser to collect aromatic products and then a H2-permeable membrane separator to remove H2. The unreacted CH4, C2 products and H2 residual in the product stream were sent to the recycle loop for the next round of DNMC reaction and H2 removal. The results demonstrated that >90 % product selectivity toward aromatics and >50 % aromatics yield are achieved in the gas recycle CH4 reactor/ H2 membrane separator system.