Sorption-enhanced syngas-to-olefins in a dual-zone fluidized-bed reactor: Integrated kinetic–adsorption modeling and process intensification

The sorption-enhanced syngas-to-olefins (SEOS) process provides an intensified pathway for olefin production by integrating syngas hydrogenation, methanol-to-olefins (MTO) conversion, and in-situ water removal within a single reactor. In this work, a MATLAB-based model was developed for a dual-zone fluidized-bed system formed through natural hydrodynamic segregation of Zn–Zr, SAPO-34, and 3 A molecular sieve particles. The lower zone promotes CO/CO₂ hydrogenation to methanol and dimethyl ether, while the upper zone converts intermediates to light olefins with continuous water removal. The model incorporates intrinsic kinetics, Langmuir-type adsorption, and bed expansion correlations, and was validated against experimental data, showing close agreement in carbon conversion and olefin selectivity. Parametric studies indicate that CO₂ addition (5–10%) lowers overall carbon conversion from 15.5% to 12.8% but exerts little influence on olefin distribution, where propylene (~45%) remains dominant. The inclusion of 3 A sieves enhances carbon conversion up to 20% by suppressing reverse water–gas shift and alleviating water inhibition on SAPO-34. Temperature analysis identifies an optimum near 400 °C, maximizing light-olefin yields while limiting secondary hydrogenation. These results demonstrate that dual-zone SEOS reactors effectively broaden the operating window, improve efficiency, and offer a viable route for sustainable olefin production. • A new intensified sorption-enhanced olefin synthesis (SEOS) process is proposed • A model incorporating reaction and adsorption kinetics and bed expansion correlations is developed. • The inclusion of molecular sieves in the system enhances carbon conversion. • CO₂ in feed syngas lowers overall carbon conversion but exerts little influence on olefin distribution.