A gas-liquid stirred tank reactor (STR) has some problems, such as low mass transfer efficiency, high exhaust gas oxygen concentration, and low product conversion rate, due to limitations of stirring speed and input power. This article proposes a method to enhance the gas-liquid mass transfer in a STR using circulating jet internals. When a circulating jet is added, the average bubble size in the reactor is reduced to 1.26 mm, and the overall gas holdup is increased to 8.23%, which is an increase of 3.62 times of the original STR. The gas-liquid volumetric mass transfer coefficient is increased to 0.05556 s-1, which is 4.84 times of the original STR. The unit volume power is increased by only 1.4 times. These data provide references for the design and scale-up of new jet STRs.
An industrial-scale internal loop airlift reactor is used to remove volatile gas from high-viscosity molten sulfur. The effects of the superficial gas velocity and reactor height on the hydrodynamic characteristics were studied. The gas holdup, average bubble diameter, and liquid circulation velocity in the reactor under different conditions were analyzed using computational fluid dynamics simulation. The superficial gas velocity was varied from 0.0056 m/s to 0.05 m/s at a constant reactor height of 15 m. The total reactor height was varied from 5 m to 25 m at a superficial gas velocity of 0.0389 m/s.Based on the correlation between the gas holdup and liquid circulation velocity proposed by Chisti (1988), an optimized correlation between the gas holdup and liquid circulation velocity was developed by considering the influence of the bubble diameter. The results obtained using the proposed correlation were compared with those obtained using the Chisti correlation and simulation.
Based on the premise that large bubbles are removed in larger cyclones and small bubbles are removed in smaller cyclones, a combined degassing hydrocyclone with main and subsidiary chambers was designed to enhance liquid degassing. The liquid feed volume flow rate ranged from 0.377 to 1.459 m3/h, and the gas feed volume flow rate ranged from 0.197 to 1.000 m3/h. The pressure loss, liquid flow rate at the gas outlet, split ratio, gas flow rate at the liquid outlet and degassing efficiency of the degassing hydrocyclone were measured and calculated. Correlative equations for pressure loss and degassing efficiency were established. The experimental results show that the degassing hydrocyclone can remove most of the gas and has good degassing performance in a large gas-liquid flow rate range. The parameter contours provide an effective foundation for the removal of gas from industrial fluids.