One of the obstacles constraining bio‐ethanol production using cellulose is enzymatic hydrolysis. Uniform distribution of slurry residence time is important to improve the efficiency. Efforts were made to develop a novel quasi plug‐flow reactor on industrial scale for enzymatic hydrolysis of cellulose by CFD simulation. Ahead of numerical simulation, the rheological properties of the cellulose enzymolysis slurry of furfural residues were studied based on experiments. A turbulence model called k‐kl‐ω was employed in CFD simulation, which was good at describing the flow field with great variation on the extent of turbulence in the stirred tank. Vertical blades, pitched blades, helical ribbons, and their combination were investigated firstly, and then the internal structures were optimized. The calculated residence time distribution curve showed that the quasi plug‐flow reactor had the following features: (1) combination of double helical ribbons and vertical blade, (2) two partitions and four baffles, (3) flow area was 0.1 m2 on partitions. The CFD simulation methods and results could provide a theoretical guidance for the development of a novel quasi plug‐flow reactor to improve the efficiency of the cellulose enzymatic hydrolysis on industrial scale.

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Partial oxidation of methane (POM) is a preferred method for synthesis gas, which usually occurs in fixed bed reactors. In this paper, the discrete element method (DEM) is used to reconstruct the structure of a reactor bed via simulating the process of filling the reactor with catalyst. The particle resolved CFD physical model with the detailed micro-kinetcis of the POM reaction was established to study the interaction among reactant flow, heat and mass transfer, and reaction in the fixed bed. The gas composition and temperature distribution in the reactor were obtained based on the simulation results. The effects of the space velocity and the reaction temperature on the CH 4 conversion, catalyst selectivity, and catalyst surface coke formation were analyzed. The simulation results show that the temperature hot spots of the catalyst in the bed occur at the inlet and the temperature increases further near the wall. With the increase in space velocity, the conversion rate of CH 4 decreases gradually, and the selectivity does not change significantly. As the temperature increases, the conversion rate of CH 4 gradually increases and the selectivity decreases. The risk of coke formation on the catalyst surface rises axially and the C species concentration is relatively higher near the outlet. Appropriately increasing the gas velocity and increasing the temperature helps to reduce the surface coke accumulation of the catalyst. K E Y W O R D SCFD, coke formation, conversion rate, hot spots, POM