Oxidative coupling of methane over lanthanum and strontium promoted magnesium catalyst

Abstract

The oxidative coupling of methane (OCM) over 10wt.%SrO/10wt.%La2O3/MgO, in the form of particulate and monolithic structures, was investigated in this thesis. The OCM performance of the catalyst, which was prepared using incipient to wetness impregnation and then wall-coating over the monolithic support, was investigated in a microflow quartz reactor.. The diameter of reactor was 10 mm around the catalyst bed and reduced to 2 mm at the exit to decrease the void volume, which was also filled with quarts chips to prevent undesired gas phase reactions. At the beginning of work, 10wt.%La2O3/MgO particulate catalyst was prepared by incipient to wetness impregnation and tested. At the following stages, the additional metal oxides (CaO and SrO) were also added. The highest yield was 8wt.% in particulate catalysts and it was observed over 10wt.%SrO/10wt.% La2O3/MgO. For the test over mullite monolith, the monolith blocks were shaped to 17 mm height and 8 mm ID first, and then they were wash-coated with MgO followed by La2O3 and/or SrO. The highest C2 yield (14.5%) was obtained at 650 oC with CH4/O2 ratio of 15 using 10wt.%SrO/10wt.% La2O3/MgO over monolith.