Oxidative dehydrogenation of ethane to ethylene in an integrated CO2 capture-utilization process

Integrated carbon capture-utilization provides a viable approach to curb anthropogenic CO2 emissions and, at the same time, produce valuable chemicals and fuels from a waste carbon feedstock. Herein, we report in-situ capture and utilization of CO2 in ethylene production through oxidative dehydrogenation of ethane over adsorbent-catalyst materials consisting of double salt K-Ca and Cr-impregnated H-ZSM-5. The adsorption step was conducted at 600 degrees C using 10 % CO2/Ar, followed by the reaction step at 700 degrees C using 5 % C2H6/Ar. An adsorption capacity of 5.2 mmol/g was obtained for K-Ca at 600 degrees C. The effects of Cr content, C2H6 feed concentration and weight hourly space velocity (WHSV) were investigated to determine the optimum process conditions for this combined process. Under 5000 mL/g h and 5 vol% C2H6 feed concentration, Cr-10/HZSM-5 physically-mixed with K-Ca (weight ratio of 1:1) exhibited the highest ethane conversion at 25 % with ethylene selectivity of 88 %, owing to its higher turnover frequency (TOF) number and lower Cr surface density.