Study On The Basis And Application Of Solid-Liquid Mass Transfer Enhanced By Higee

The solid-liquid mass transfer process is widely used in industrial production,such as wastewater treatment,drug extraction and fuel processing,etc.Traditional solid-liquid mass transfer process is usually realized in stirring tank(STR)device.Due to low solid-liquid mass transfer efficiency,STR method usually owns large size,consumes high energy,and needs long-time processing.As a typical means of chemical process intensification,Higee technology is widely used in chemical separation and reaction processes,which shows great advantages in intensifying multiple phase mass transfer and mixing processes.According to the application system,the current application of Higee technology mainly focuses on gas-liquid,gas-solid,liquid-liquid and gas-liquid-solid systems.The study of solid-liquid mass transfer process intensification by Higee technology is still lacking,and the effect and mechanism of Higee intensification are not yet clear.In this paper,the mechanism of solid-liquid mass transfer intensified by Higee was investigated,and the Higee technology was applied to the solid-liquid mixing and dispersive processes such as white oil refining and polyacrylamide(PAM)solution preparation.Based on the experimental system of activated clay adsorbing phenol in water,the basic theory of Higee intensifying solid-liquid mass transfer was studied.Isothermal adsorption and thermodynamic experiments showed that the equilibrium relationship of adsorption of phenol on activated clay was consistent with Langmuir model,and the adsorption heat was-7.146 kJ·mol-1,indicating that phenol in water adsorbed by activated clay was a physical adsorption process of a single molecular layer.The kinetic study show that the whole adsorption process fits well with the pseudo-second-order kinetic equation,and the internal and external diffusion are both rate control steps.In this experiment,the adsorption capacity in RPB can reach 12.38 mg·g-1 under the optimal conditions,which is about 19%higher than the 10.39 mg·g-1 of STR under the same operating conditions.At this point,the internal diffusion rate constant is 2.3703 mg·g-1·min-0.5,which is 1.28 times of the internal diffusion rate constant in STR under similar conditions.The external diffusion rate constant is 0.8892 cm·s-1,which is 1.65 times of the external diffusion rate constant of STR under similar conditions.The experimental results show that RPB can improve the adsorption rate and adsorption rate of phenol in activated clay.In view of the significant intensifying effect of RPB on the adsorption process,an experimental study was carried out to study the effects of rotation speed,liquid flow,solid content and temperature on the adsorption and refining effect of Higee intensifying white oil adsorption and refining.Finally,the optimal operating conditions in RPB were determined as follows:rotation speed was 1000 rpm,liquid flow was 20 L·h-1,active clay content was 15 g·L-1,and temperature was 368.15 K.Under these conditions,the absorbance of white oil after RPB treatment decreased to 1.29,which was obviously better than the result of STR treatment(1.63).The feasibility of preparing polymer aqueous solution by rapid dispersion of polyacrylamide reinforced by Higee was investigated.The effects of different operating parameters on the dispersion and dissolution of polymer were investigated.By comparing the basic physical properties of low-concentration polymer solution prepared by RPB method and STR method,it was found that the molecular weight,characteristic viscosity,filtration coefficient and water-insoluble content of polymer aqueous solution were almost equal,but the solution viscosity obtained by RPB method was slightly higher.The polymer solution obtained by RPB method has better shear resistance,stability and oil recovery than that obtained by STR method.Compared with STR,RPB method not only realizes continuous operation,greatly shortens the dissolution time of the polymer,but also saves space,making it of high application value in polymer dissolution,especially in the limited space such as offshore platform.