Oil refineries are responsible for 4–6% of global CO₂ emissions, and 20–35% of these emissions released from the regenerator of Fluid Catalytic Cracking (FCC) units, which are the essential units for the conversion of heavier petroleum residues (vacuum gas oil) into more valuable products. Chemical looping combustion (CLC) has been recently proposed to mitigate the CO₂ emissions released from the regenerator of FCC units with a lower energy penalty. However, a detailed experimental and modelling investigation is still necessary in order to identify the hydrodynamics in the regenerator of chemical looping combustion integrated with fluidised catalytic cracking (CLC-FCC). A computational fluid dynamic (CFD) study was conducted to understand the hydrodynamic behaviours of gas-solid two-phase flow in the regenerator of the CLC-FCC unit, based on a three-dimensional multiphase model (Eulerian-Eulerian) with the kinetic theory of granular flow.

The results provide a useful insight into regenerator hydrodynamics, in terms of oxygen carrier modified FCC catalysts and FCC coke distribution profiles, in the regenerator of CLC-FCC. The conventional drag models (Syamlal-O'Brien and Gidaspow) predict a bed density profiles of a dense phase (250–300 kg/m³) at the dense phase (0–0.25 of h/H), and a dilution phase from h/H = 0.25 to 0.50 of regenerator. The bed density profile is indistinguishable from the industrial data provided for conventional FCC regenerators. The fluidisation gas (CO₂) passes through the centre of the regenerator where the fluidisation gas splits the catalyst particles from the centre to the walls, to create a dilute particle phase in the centre and a dense particle-phase near the wall, which is one of the characteristic flow regimes in circulating fluidised bed reactors. The particles in the centre demonstrate an upward flow trend with a particle velocity above 3.0 m/s while the dense particles near the wall tend to go down with relatively low particle velocity of <0.5 m/s, which creates vortexes and a non-uniform particle distribution in the regenerator. The distribution of the fluidising gas provides better mixing of solid particles in the entrance and the optimisation of the superficial gas velocities (1.0 m/s) to create a distributed flow regime with developed vortexes through the dense and dilute phases. Furthermore, the laminar and turbulent flow models demonstrated no significant differences in terms of axial bed density profile in the regenerator of the CLC-FCC concept. These findings demonstrated that the hydrodynamics of catalysts in the CLC-FCC regenerator successfully predicted with CFD modelling and the prediction results aligned well with the conventional FCC regenerator.

炼油厂占全球 CO ₂排放量的4-6% ，其中 20-35% 的排放来自流化催化裂化 (FCC) 装置的再生器，这些装置是重质石油残渣（真空瓦斯油）转化为更有价值的产品。最近已提出化学循环燃烧 (CLC) 以减轻 CO ₂FCC 装置的再生器释放的排放物具有较低的能量损失。然而，为了确定与流化催化裂化 (CLC-FCC) 集成的化学循环燃烧再生器中的流体动力学，仍然需要进行详细的实验和建模研究。基于动力学理论的三维多相模型（欧拉-欧拉），进行了计算流体动力学（CFD）研究，以了解 CLC-FCC 装置再生器中气固两相流的流体动力学行为粒状流。

在 CLC-FCC 再生器中，根据氧载体改性的 FCC 催化剂和 FCC 焦炭分布曲线，该结果提供了对再生器流体动力学的有用见解。传统阻力模型（Syamlal-O'Brien 和 Gidaspow）预测密相（0-0.25 h/H）的密相（250-300 kg/m ³）和稀释相的床密度分布h/H = 0.25 至 0.50 的再生器。床密度分布与为传统 FCC 再生器提供的工业数据无法区分。流化气（CO ₂) 通过再生器的中心，流化气体将催化剂颗粒从中心分裂到壁，在中心形成稀颗粒相，在壁附近形成致密颗粒相，这是特征流态之一在循环流化床反应器中。中心的颗粒表现出向上流动趋势，颗粒速度高于 3.0 m/s，而靠近壁的致密颗粒倾向于以 <0.5 m/s 的相对较低的颗粒速度下降，这会产生涡流和不均匀再生器中的颗粒分布。流化气体的分布使入口处的固体颗粒更好地混合并优化了表观气体速度 (1. 0 m/s) 以通过稠密相和稀相创建具有发达涡流的分布式流态。此外，层流和湍流模型在 CLC-FCC 概念的再生器中的轴向床密度分布方面没有显着差异。这些发现表明，CLC-FCC 再生器中催化剂的流体动力学成功地通过 CFD 模型进行了预测，并且预测结果与传统的 FCC 再生器非常吻合。