Study On Transfer Characteristics Of Chlor-alkali Industrial Electrolytes Based On PBM Model

Ion exchange membrane electrolysis technology is currently the most important production method in the chlor-alkali industry.Ion exchange membrane electrolysis cell is the core equipment for alkali production technology.Many scholars have studied the temperature field,speed field,concentration field,gas content,and gas and liquid phase in the electrolyzer.The mixing situation,There is relatively little research on bubble dynamics.In past studies,most of them used uniform bubble assumptions when simulating gases.In the actual production process,there are complex interactions between bubbles and bubbles and electrolytes,which will cause bubbles to continue to coalesce and break up.The complex evolution of bubble behavior,size and distribution is caused.These interphase forces have a direct influence on the fluid mechanics behavior and flow field structure in the ion membrane electrolyzer,which in turn affects the electrolytic efficiency of the electrolyte.Therefore,it is of great significance to study the motion characteristics of air bubbles in electrolytes.In this paper,a numerical study of the anode Chamber of the electrolytic cell is conducted using fluid mechanics software.UDF program is added in the simulation to realize the reaction on the membrane surface.A CFD-PBM coupling model is established to incorporate the study of the condensation and fragmentation of air bubbles into the CFD framework.The distribution of bubble size in the electrolytic cell after condensation and fragmentation was studied.Considering the change of the flow field structure when the bubbles are coalesced and broken.The influence of bubble fusion and crushing behavior on the distribution of gas content,etc.,verified the correctness of the CFD-PBM model by measuring the liquid flow speed at different heights in the electrolytic cell and comparing the experimental value with the simulation results.Through bubble size distribution and bubble dynamics experiments,the influence of bubbles on fluid flow is further proved.The main conclusions of this paper are as follows:(1)Considering that the concentration,fragmentation,and hypothetical bubbles all differ in the distribution of momentary gas holdup,the fusion and fragmentation of bubbles do have a certain influence on the gas phase structure.When considering the integration and fragmentation of bubbles,The distribution of gas content is more consistent with the actual situation.(2)The bubbles of each bubble group are distributed in the electrolytic cell.The atmospheric bubbles are widely distributed in the electrolytic cell and have a large number of densities.Bubbles with diameters ranging from 0.064 mm to 0.084 mm perform as a result of increasing the current density from 4.5 KA/m2 to 5KA/m2.As the current density decreases,the number of bubbles with a diameter of 0.564 mm increases.The distribution range is wide,and there are different numbers of distributions in the entire electrolytic cell.(3)The fusion of bubbles is a complex process.The size of bubbles,the distance between bubbles,and the physical properties of bubbles all affect the fusion rate of bubbles.