Scale-up Studies On Airlift Loop Reactor

The Airlift Loop Reactor(ALR) is developed based on the conventional bubble column, it is composed of the reactor outside tube, diversion tube, nozzle(or gas distributor), the gas and liquid export. The reactor has a good operation of low energy consumption, good circulation, uniform distribution of gas holdup, and good mass transfer characteristics. It is used in chemical engineering, bio-engineering, coal chemical industry and environmental engineering, in the Slurry bed hydrocracking technology has good application prospect. But because of the complexity of the flow inside the ALR, the reactor industry still has a lot of uncertainty.In this paper, used the computational fluid dynamics numerical simulation software Fluent, based on the two-fluid model established the numerical simulation model of the ALR. In the computational model using the standard k-epsilon turbulence model, and considering the drag and lift force of gas-liquid-solid, bubbles in the turbulent dissipation and coalescence and breakage and so on. Comparing with different structure parameters of the ALR detailed numerical simulation research, lays the foundation for the ALR next industrial amplification.First in two phase numerical simulation, study the different structure of the ALR, respectively investigates the reactor in different height, diameter and volume, the average gas holdup, local gas holdup and the liquid circulation velocity distribution in the ALR and the change rule. Then according to the general principles of reactor amplification proposed three make the reactor capacity increases 2 times amplification scheme, change the reactor diameter, height and change the height and diameter, and study the average gas holdup, local gas holdup and the liquid circulation velocity distribution in the ALR and find which one scheme’s reactor close to the original reactor.Based on the E/E/E method establish the gas-liquid-solid three phase numerical simulation model, investigated by the software Fluent to simulate numerical calculation the distribution of gas phase and solid phase of the ALR, and the influence of the addition of solid phase on the gas phase distribution and different taper of reactor solid phase accumulation at the bottom of the reactor.Based on two-fluid model of two phase numerical calculation, the reactor height increase of little influence on overall gas holdup, annular gas holdup increases slightly and the circulation effect is improved; With the increase of the reactor diameter, the annular gas holdup has a tendency to reduce; Maintain the ratio of height to diameter unchanged increase the reactor volume, the circulation effect improve slightly, but the annular gas holdup has a tendency to reduce. In the three kinds of scheme of reactor capacity increases 2 times, the maintain the ratio of height to diameter unchanged reactor is the most close to the original reactor condition. Three-phase simulation, can clearly know the flow and distribution of the solid phase in the bottom of the reactor, with the taper increased at the bottom of the reactor the flow improved at the bottom of the reactor.