Work

A comprehensive thermodynamic equilibrium analysis of direct CO2 hydrogenation to light olefins product

Year: 2025

Type: article

Abstract: Thermodynamic equilibrium analysis is a powerful tool for assessing the feasibility of chemical reactions and product distributions under different operating conditions. This study investigates the feasibility and intrinsic nature of each possible reaction in CO 2 hydrogenation using the equilibrium constant (K) method and calculating thermodynamic parameters. In addition, the equilibrium product distribution and CO 2 conversion of CO 2 hydrogenation to light olefins (CTO) process determined at temperature range of 200–400℃, pressure of 1–50 bar, and different H 2 /CO 2 feed ratios (1, 2, 3, and 4) using Gibbs free energy (GFE) minimization method. The results indicate that, elevated temperatures strongly promote the formation of light olefins while effectively suppressing coke deposition, pressure exerts a moderate enhancing effect, and a higher H 2 /CO 2 ratio, particularly at lower temperatures, significantly reduces coke formation while having only a minor influence on light olefins selectivity. In contrast, CO 2 conversion decreases markedly with increasing temperature, while higher pressure and elevated H 2 /CO 2 ratios enhance the conversion. Ultimately, the maximum selectivity of light olefins (1.22 ×10 −7 ) was obtained at 400℃, 50 bar, and H 2 /CO 2 = 3, under which coke formation was completely suppressed, although the corresponding CO 2 conversion was only 7.6 %. These findings highlight not only the intrinsic nature of the CTO process and the influence of operating conditions on its equilibrium product distribution, but also provide valuable guidance for catalyst development in the absence of extensive experiments.

Source: Journal of CO2 Utilization

DOI: 10.1016/j.jcou.2025.103238

Authors: Farshid Sobhani Bazghaleh, Jafar Towfighi Darian, Yosef Niktab, Masoud Safari Yazd

Institution: Tarbiat Modares University

Language: English

Topic: Catalysts for Methane Reforming

Subfield: Catalysis

Field: Chemical Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Climate action

Open Access status: gold

Estimated APC paid: $3,360