Effects of Rare Earth Metal Promotion over Zeolite-Supported Fe–Cu-Based Catalysts on the Light Olefin Production Performance in Fischer–Tropsch Synthesis

Abstract

Fischer−Tropsch synthesis (FTS), a significant reaction for effective H 2 utilization, is a promising approach for direct production of light olefins from syngas (H 2 + CO). For the FT-Olefin process, an efficient catalyst restricting the product distribution of FTS to light olefins is required. Aligned with this goal, we synthesized 24 catalysts comprising Fe and Cu in combination with rare earth metals (La, Ce, Nd, Ho, Er) and zeolite supports (ultrastable Y and mordenite). FT-Olefin performances of these catalysts were screened using a high-throughput test system at atmospheric pressure, and then promising catalysts were tested under high pressure in a conventional test system. Results show that Nd increases selectivity to light olefins and Ho suppresses C 5 + and coke formation. It is also demonstrated that zeolite−metal interaction, leading to a mixture of both acidic and basic sites, is significant in increasing light olefin production. The mordenite-supported 20 wt % Fe, 0.5 wt % Cu, and 0.5 wt % Ho catalyst provides the highest light olefin yield with the lowest coke and heavier hydrocarbon selectivity.

Caracterização e avaliação de catalisadores de Fe suportado em zeólita HZSM-5 para a síntese de Fishcer-Tropsch

“…Thus, for this catalyst, higher hydrogen pressure increased CO conversion while reduced CO2 selectivity, favoring FTS reaction over the parallel WGS reaction. This finding is in good agreement with Burgun et al (2023) 174 that studied Fe-Cu catalysts supported on zeolite Y and mordenite for the FTS. The catalysts showed a decrease of CO2 with a higher H2/CO ratio.…”

“…(2023) 174 , who reported a similar initial decrease in CO conversion while testing Fe catalysts supported on zeolite Y and mordenite for FTS. According to the authors, initial coke deposition was regarded as a possible explanation to the decrease in the catalyst activity.…”