Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges r...Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges related to inadequate mass transfer and a high pressure drop caused by the non-uniform void fraction distribution.To enhance the overall performance of fixed beds,the impact of different packing configurations on performance was investigated.Experimental and simulation methods were used to investigate the fluid flow and mass transfer performances of various packed beds under different flow rates.It was found that structured beds exhibited a significantly lower pressure drop per unit length than conventional packed beds.Furthermore,the packing configurations had a critical role in improving the overall performance of fixed beds.Specifically,structured packed beds,particularly the H-2 packing configuration,effectively reduced the pressure drop per unit length and improved the mass transfer efficiency.The H-2 packing configuration consisted of two parallel strips of particles in each layer,with strips arranged perpendicularly between adjacent layers,and the spacing between the strips varied from layer to layer.展开更多
For studying the mixing tank for RMAC (residue upgrading to maximize asphaltene conversion) reactor, the CFD simulation was employed to simulate the flow field in the mixing tank. The dispersion of liquid-liquid phase...For studying the mixing tank for RMAC (residue upgrading to maximize asphaltene conversion) reactor, the CFD simulation was employed to simulate the flow field in the mixing tank. The dispersion of liquid-liquid phase in the mixing tank and the power of turbines were investigated. The simulation results showed that compared with the original doublelayer propeller, the A310-swept double-layer impellers could reduce the liquid heterogeneous degree by 27.5% and the stirring power by 3.25%. The influence of rotation speed on the heterogeneous degree and stirring power was investigated, and the critical rotation speed was obtained. The optimal rotation speed was determined to be 240 r/min. The heterogeneous degree was 0.19 and the minimum stirring power was 10.89 W. By optimizing the impeller selection and process conditions, the overall performance of the mixing tank could be significantly improved.展开更多
The transfer rate between fluids in a microreactor is directly influenced by the mixing within the reactor, which subsequently impacts the reaction rate. This paper investigates the flow behavior and macro-mixing perf...The transfer rate between fluids in a microreactor is directly influenced by the mixing within the reactor, which subsequently impacts the reaction rate. This paper investigates the flow behavior and macro-mixing performance in a microreactor. First, the flow performance of the Ehrfeld Miprowa microreactor is studied. Cold experiments are conducted to examine fundamental flow laws and verify the accuracy of the chosen computational fluid dynamics simulation model.Subsequently, macro-mixing performance in the microreactor, both with and without internal components, is investigated through both experiment and simulation. A bromocresol violet–NaOH–H2SO4 system is utilized in the macro-mixing experiments, which explore the effects of flow rate and internal components on macro-mixing. The Navier–Stokes equation is adopted as the computational model for macro-mixing simulations, which also consider the mass transfer and diffusion of tracer. The simulation results are in good agreement with the experimental results. Both experimental and simulation results demonstrate that the presence of internal components in the microreactor enhance its macro-mixing performance.展开更多
文摘Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges related to inadequate mass transfer and a high pressure drop caused by the non-uniform void fraction distribution.To enhance the overall performance of fixed beds,the impact of different packing configurations on performance was investigated.Experimental and simulation methods were used to investigate the fluid flow and mass transfer performances of various packed beds under different flow rates.It was found that structured beds exhibited a significantly lower pressure drop per unit length than conventional packed beds.Furthermore,the packing configurations had a critical role in improving the overall performance of fixed beds.Specifically,structured packed beds,particularly the H-2 packing configuration,effectively reduced the pressure drop per unit length and improved the mass transfer efficiency.The H-2 packing configuration consisted of two parallel strips of particles in each layer,with strips arranged perpendicularly between adjacent layers,and the spacing between the strips varied from layer to layer.
基金supported by the Major Science and Technology Project of SINOPEC (ST18012-4)
文摘For studying the mixing tank for RMAC (residue upgrading to maximize asphaltene conversion) reactor, the CFD simulation was employed to simulate the flow field in the mixing tank. The dispersion of liquid-liquid phase in the mixing tank and the power of turbines were investigated. The simulation results showed that compared with the original doublelayer propeller, the A310-swept double-layer impellers could reduce the liquid heterogeneous degree by 27.5% and the stirring power by 3.25%. The influence of rotation speed on the heterogeneous degree and stirring power was investigated, and the critical rotation speed was obtained. The optimal rotation speed was determined to be 240 r/min. The heterogeneous degree was 0.19 and the minimum stirring power was 10.89 W. By optimizing the impeller selection and process conditions, the overall performance of the mixing tank could be significantly improved.
基金supported by the National Natural Science Foundation of China (No. 5197050207)。
文摘The transfer rate between fluids in a microreactor is directly influenced by the mixing within the reactor, which subsequently impacts the reaction rate. This paper investigates the flow behavior and macro-mixing performance in a microreactor. First, the flow performance of the Ehrfeld Miprowa microreactor is studied. Cold experiments are conducted to examine fundamental flow laws and verify the accuracy of the chosen computational fluid dynamics simulation model.Subsequently, macro-mixing performance in the microreactor, both with and without internal components, is investigated through both experiment and simulation. A bromocresol violet–NaOH–H2SO4 system is utilized in the macro-mixing experiments, which explore the effects of flow rate and internal components on macro-mixing. The Navier–Stokes equation is adopted as the computational model for macro-mixing simulations, which also consider the mass transfer and diffusion of tracer. The simulation results are in good agreement with the experimental results. Both experimental and simulation results demonstrate that the presence of internal components in the microreactor enhance its macro-mixing performance.
