Numerical Smulation Of Stirring Reactor For Hydrogenation Of Dinitrotoluene

In this paper,the catalytic hydrogenation reaction of 2,4-dinitrotoluene was studied from many aspects by CFD.Firstly,the gas-liquid two-phase flow in two different tanks was simulated,then a reactor with the best performance was selected to simulate the catalytic hydrogenation reaction of 2,4-dinitrotoluene for the first time,finally,gas-liquid two-flow simulation was carried out on the enlarged double-layer reactor to lay a foundation for reactor design and 2,4-dinitrotoluene chemical reaction simulation.The main research content is as follows:?1?the steady state simulation study of the gas-liquid two phase fluid behavior in a three-blade propeller reactor with coiled tubes was conducted by Euler two-phase flow model in the H₂O-H₂ system.In the solving process,the geometric model was discreted by polyhedron mesh,the RNG k-?model was used for turbulence model,and the blade area was processed by MRF method.Through the simulations of 12 different conditons,the results show that when the liquid level height is 130mm and the stirring speed is 1800rpm,the three-blade propeller reactor has the largest inspiratory capacity,that is to say,the lower the liquid level height is,the higher the stirring speed is,and the greater the air intake in the reactor is.In order to ensure the reliability of the simulation results,the simulation structure is compared with the experimental data in the literature,and the results are basically consistent.?2?with the same reactor size,the gas-liquid two phase simulation study was carried out on 9 different conditions of the gas self-induced reactor by orthogonal test.By studying the influence of different liquid level height,blade hanging height and stirring speed on the inspiratory rate of the gas self-induced reactor,it was also found that the inspiratory rate was the highest,when the liquid level height was 130mm and the stirring speed was 1800rpm,and the simulation results were compared and verified with the simulation results in the literature.Finally,the two stirred reactors were compared in many aspects,and it was found that the gas self-induced reactor was more suitable for the catalytic hydrogenation reaction of 2,4-dinitrotoluene.?3?the catalytic hydrogenation reaction of 2,4-dinitrotoluene was simulated in the gas self-induced reactor with the best performance.Based on the previous experimental research institute of the main reaction kinetics equation,the reaction thermodynamics of physical parameters were calculated at 373 k,when conditions of the reaction were1800rpm,2,4-dinitrotoluene concentration was 8%,the catalyst concentration was0.3%,the reaction pressure of 20 bar.the realization of the reaction process need to establish a numerical model of chemical reaction source term by UDF programming,eventually the corresponding changes of the stress,concentration and temperature field were acquired at different time.The research shows that the higher the temperature of the reaction,the faster the reaction rate,and the higher the 2,4-dinitrotoluene conversion rate at the same position.?4?the three-blade propeller blade and CBY-H respectively as the lower blade,self-priming blade as the upper blade,the 2L self-priming reactor was amplified to 500L by the geometric similar amplification method,then the gas liquid two phase flow in the two double blade types reactors were simulated,the results showed that:CBY-H as the lower blade,its liquid pumping ability is better.