Conditions for the Joint Conversion of CO(2) and Syngas in the Direct Synthesis of Light Olefins Using In(2)O(3)–ZrO(2)/SAPO-34 Catalyst

[Image: see text] The conditions for promoting the joint conversion of CO(2) and syngas in the direct synthesis of light olefins have been studied. In addition, given the relevance for the viability of the process, the stability of the In(2)O(3)–ZrO(2)/SAPO-34 (InZr/S34) catalyst has also been pursued. The CO+CO(2) (CO(x)) hydrogenation experimental runs were conducted in a packed bed isothermal reactor under the following conditions: 375–425 °C; 20–40 bar; space time, 1.25–20 g(catalyst) h mol(C)(–1); H(2)/(CO(x)) ratio in the feed, 1–3; CO(2)/(CO(x)) ratio in the feed, 0.5; time on stream (TOS), up to 24 h. Analyzing the reaction indices (CO(2) and CO(x) conversions, yield and selectivity of olefins and paraffins, and stability), the following have been established as suitable conditions: 400 °C, 30 bar, 5–10 g(cat) h mol(C)(–1), CO(2)/CO(x) = 0.5, and H(2)/CO(x) = 3. Under these conditions, the catalyst is stable (after an initial period of deactivation by coke), and olefin yield and selectivity surpass 4 and 70%, respectively, with light paraffins as byproducts. Produced olefin yields follow propylene > ethylene > butenes. The conditions of the process (low pressure and low H(2)/CO(x) ratio) may facilitate the integration of sustainable H(2) production with PEM electrolyzers and the covalorization of CO(2) and syngas obtained from biomass.