Experimental and Theoretical Investigation on Methane Dehydroaromatization under Non-Oxidative Conditions
Sonit Balyan (Prof. K. K. Pant)
12th April 2017, Wednesday, 04:00‐04:30 pm (25+5 mins), ChE Seminar hall
Advances in hydraulic fracturing technology have unlocked vast resources of low-cost natural gas. With a high H/C atom ratio, CH4 have a smaller carbon footprint than either coal- or petroleum-derived fuels, use of low-cost, environmentally friendly CH4 as a feedstock for the manufacture of high-value chemicals would revolutionize the chemicals industry. But its economical valorization is impeded by stranded location of natural gas reserves which can be untangled by efficient conversion of natural gas into transferable liquid. Current industrial practice requires multiple processing steps, usually through a synthesis gas intermediate, which results in high capital costs and low overall energy and carbon efficiencies. Single step, or “direct,” conversion processes, in which CH4 molecules are coupled to form ethylene (C2H4) or aromatics in a single reactor using shape selective Mo/Zeolites based catalysts, have been the subject ofindustrial and academic research for decades. Despite of potential it has not been adopted because of fast catalyst deactivation. In order to minimize the coke deposition various process parameters like calcination temperature, α-MoC1-x have been checked during the catalyst activity test by validating through coke gasification kinetics using Kissinger plot.
DFT calculation has been employed to study the CH4 activation on the above mentioned cluster all the way to the formation of C2H4, one of the most important intermediate for methane dehydroaromatization process. Methane is activated on the Mo2C6 cluster with an intrinsic activation barrier ~ 117 kJ/mol. The highest intrinsic barrier ~ 134.7 kJ/mol was obtained for second methane activation. The activation of C2H6 (~122.4 kJ/mol) has almost similar value to that of first C-H bond activation and thus C2H4 formation is easier on the catalyst surface.