Gas-Liquid Mixing: Physical Considerations

Gas-liquid reactors in the chemical process industries (CPI) have increasingly been designed to handle larger manufacturing scales. Since gas-liquid reactors can represent substantial capital and operating costs for the user, optimizing mixing and maximizing productivity are critical. The need for efficiency at larger scales places more importance on understanding the physical phenomena of mixing and more of a burden on equipment design. Physical demands of mixing A number of complex physical phenomena must be considered to achieve optimal function of mixing equipment in cases where gaseous and liquid substances interact. For a gas-liquid reaction to occur, a low-density compressible gas must be dispersed into a much denser liquid with a reasonably long contact time. Usually, significant turbulence must be induced into the liquid phase to aid mass transfer and reaction. In addition, rapid movement of the liquid phase is often required at heat-transfer surfaces, which are often removed by some distance from mixing impellers. In some cases, the liquid phase can contain a significant level of solids, which must be kept suspended. Gas-liquid reactors commonly consist of large pressure vessels with sophisticated internal components for…