Research Of Gas-Liquid Mass Transfer And Mixing In Xanthan Gum System

Rheological characteristics of different Xanthan gum solutions are studied in this paper. The regressions between consistency index K , flow behaviour index n and the concentration of Xanthan gum Cp are investigated. Mixing performance of impellers such as Maxblend, Sanmeler, Fullzone, Double-Knife, Mig, Inter-Mig is researched in pseudoplastic xanthan gum system. The data about power consumption, gas hold-up, oxygen mass transfer coefficient K_La and specific oxygen mass transfer coefficient of power input per volume Eo₂ of the impellers has been obtained. The K_La is correlated with power per unit volume P_V and superficial gas velocity VS. Meanwhile effect of three kinds of gas spargers including ring gas sparger, micro-orifice gas spargerâ… and micro-orifice gas spargerâ…¡on oxygen mass transfer in non-Newtonian fluid is also researched in this paper. The effect of micro-orifice spargers on power consumption, gas hold-upε, oxygen mass transfer coefficient K_La and specific oxygen mass transfer coefficient of power input per volume Eo₂ is emphatically investigated. Their results are compared with the values of ring type. The results show that, the properties of Xanthan gum solutions are considered Newtonian fluid as its concentration is lower; however, its properties can be described as pseudoplastic fluid with increasing its concentration. K , n can be described as the function of Xanthan gum's concentration respectively. K_La and Eo₂ of Maxblend is much higher than other agitators under the same condition, making it a superior impeller with better mass transfer and mixing performance. Furthermore, it shows that both K_La and Eo₂ of two new spargers are higher than those under the ring type. The new gas spargers have superior mass transfer and mixing performance. It is beneficial to increase oxygen concentration in non-Newtonian fluid.