Production of Gaseous Olefins from Syngas over a Cobalt-HZSM-5 Catalyst

Light olefins (C-2-C-5) are high-value platform chemicals used to produce plastics, lubricants, coating material, and surfactants, and can be intermediates to produce transportation fuels. In this study we report on the development of a Co-based catalyst for direct conversion of fossil as well as biomass derived syngas into light olefins that enables high conversion and olefin/paraffin (O/P) product ratio, minimal selectivity to CO2 (< 1%) and wax formation (C14+ selectivity < 1%). Over a Co/HZSM-5 bi-functional catalyst 38% CO conversion with C-2-C-5 olefin selectivity of 48%, and O/P ratio of 4.0 was achieved at 240 degrees C, 17 bar, and 1.5 L/(g-h). In addition to a gaseous olefin-rich stream a C-6-C-13 mixed olefin/paraffin liquid byproduct was also produced with 25% selectivity. Both Co loading and the HZSM-5 acidity levels were optimized to maintain the balance between the hydrogenation and the cracking activity to generate high levels of C-2-C-4 olefins. A suite of catalyst characterization tools were used to correlate the physical and chemical property of the catalyst to the performance of the catalyst towards syngas conversion and C-2-C-4 olefin selectivity. [GRAPHICS] .

Automated summary

A Co-based catalyst was developed for the direct conversion of fossil and biomass derived syngas into light olefins with high conversion and selectivity. Optimized Co loading and HZSM-5 acidity levels were crucial to achieving high levels of C-2-C-5 olefin selectivity.