The study focuses on Fe2O3 oxygen carrier for CO oxidation in chemical-looping combustion (CLC) system. Density functional theory (DFT) calculations were performed to detect the performance of Fe2O3 during CLC of CO. Reaction mechanism between CO and Fe2O3 was explored in details, which demonstrates that Fe2O3 with more low-fold O atoms on the surface could promote the activity of the Fe-based oxygen carrier in CLC system.

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This paper focuses on theoretical research of Co-doped Fe-based oxygen carrier for CO oxidation in chemical-looping combustion (CLC) system. Density functional theory (DFT) calculations were carried out to study of interaction between CO molecules and CoO/Fe2O3cluster, it is found that dissociation of O atom through breaking of Fe-O bonds in the Fe2O3system is the key step for CO oxidation reaction, and Low-fold O atoms in Fe2O3system could more readily dissociate from external surface. Moreover, the presence of CoO in Fe2O3could decrease activation energy and reaction energy of CO/Co-Fe2O3system, hence the reaction between CO and Fe2O3is promoted.

Through MFIX software, a three-dimensional numerical gas-solid flow models without chemical reactions is developed to the distributions of solids phase volume fraction and velocities in a 220t/h rectangular cross-section biomass CFB with a height of 3m. The maximum of erosion occurs at the near-wall side at y=0.95m on the front-wall and back-wall. In transition region(0.8-1.4m) of the left-wall and right-wall, typical core-annular regime can be observed, particle in the core region have the tendency to move to the corner. The maximum of erosion occurs at the corner formed between the walls in the role of downward movement of particle. And the lateral movement of particles are obvious enhanced between the core region and back-wall in the role of exit effect, which lead a certain degree of lateral erosion between the core region and back-wall at the left-wall and right-wall.

Biomass is an important renewable energy and making hydrogen-rich syngas from biomass is promising. Dual fluidized bed gasification technology can increase hydrogen content in the syngas. Moreover, steam gasification of biomass coupled with lime-based CO2 capture in a dual fluidized bed can further improve the syngas quality . This paper established a dual fluidized bed gasification model using Aspen plus,in order to explore the effect of different gasification temperatures and steam to biomass ratios on hydrogen content in syngas, providing a theoretical basis for the optimization of operating parameters and process.