Enhanced formation of α-olefins by the pulse process between Fischer-Tropsch synthesis and N2 purging

The Fischer-Tropsch synthesis has offered an alternative way to convert coal and biomass into chemicals such as α-olefins via syngas comprised of H2 and CO. A pulse process switching between Fischer-Tropsch synthesis and N2 purging was carried out when the Fischer-Tropsch synthesis became stable in the fixed bed reactor. The activity and selectivity over Fe-Co catalyst for α-olefins in Fischer-Tropsch synthesis reaction were measured under the normal conditions of 2.0 MPa, 497 K, 2000 h−1 and H2/CO volume ratio of 2.0. It was found that the olefin to paraffin ratio of C3 for Fe-Co catalyst purged at 517 K and 0.2 MPa was almost nine times higher than that of the fresh one without purging under the same reaction conditions, and the CH4 selectivity and CO conversion decreased after purging. Two possible reasons were proposed to explain these phenomena. Moreover, a batch experiment by the pulse process in fixed bed reactor was performed. Notably, a high olefins yield was obtained via the pulse process during the Fischer-Tropsch synthesis.