Study On Flow Characteristics Of Reverse Jet Loop Reactor

Reverse Jet Loop Reactor (RJLR) with the aid of high-speed jet and circulation, the fluid mixing effect was strengthened, heat transfer and mass transfer rate were improved, and the reaction conditions were improved, is a new type of high efficient multiphase reaction device. Based on simple structure, cheap investment, no moving parts, good sealing and mixed heat and mass transfer performance, and easy in operation, maintenance and engineering scale-up, the RJLR particularly suitable for liquid-liquid, gas-liquid and gas-liquid-solid multiphase reaction system. In chemical, biological engineering, environmental protection and other fields were widely used, and have good development prospect. But since researchers lack of systematic in research methods, test method, and research content, led to lack the basis of the scale-up and optimization of the reactor, and lack the law of research to the operation of RJLR.So in this paper the flow characteristics of RJLR was studied, the main research contents and conclusions are as follows:(1) air-water system as the research object, the effects law of structural and operating parameters of RJLR on gas holdup (e) and inspiratory capacity (QG) were studied. Experimental results show that gas holdup was increased with the increase of superficial liquid velocity and superficial gas velocity; inspiratory capacity was increased with the increase of liquid flow and the rise position of the nozzle. According to the experimental results, correlations of gas holdup were obtained as follows:(2) In the air-water system, the start law of RJLR (the minimum liquid flow of circulation starts (QLu) and the minimum liquid flow of circulation maintain (QLd), etc.). Experimental results show that were increased with the increase of nozzle position and tube diameter. QLu was slightly increased and QLd was reduced with the declining of tube position. At low gas flow (QG< 1.5m3/h), QLu, and QLd were rapidly declined with the increase of gas flow, at high gas flow (QG> 1.5m3/h), have little effect with the change of gas flow. According to the experimental results, correlations of QLu and QLd were obtained as follows:(3) Combined with Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD) to research inside velocity distribution law of RJLR, measured values and k-ε turbulence model simulation values of velocity were compared. Results show that tube inside velocity distributes as a parabola, the parabola was steeped and annular velocity was declined firstly and then increased with drop of nozzle position; The each position velocity in the reactor values were increased with increase of nozzle velocity, the experiment and simulation results were consistent, and the correctness of model was testified.(4) RJLR was applied to the synthesis of 2,4-tolylene diamine (TDA) by catalytic hydrogenation of 2,4-dinitrotoluene (DNT), RJLR volume, circulation flow, and heat transfer was designed, and the same reaction conditions of stirring tank reactor was compared. Experiments show that RJLR volume about 10% of stirred tank reactor. And the effects of cycle ratio on volume of reactor and area of heat exchanger were simulated, and finally determine the cycle ratio of reaction was 80, heat exchanger area was 355m2.