| The hydrogen sulfide chemical reaction cycle can remove H2S and SO2pollutants while preparing hydrogen and sulfuric acid.The cycle consists of the following reactions:（1）Oxidation of hydrogen sulfide:H2S+H2SO4→SO2+S+2H2O,（2）Oxidation of sulfur S+O2→SO2,（3）Bunsen reaction SO2+I2+2H2O→2HI+H2SO4,（4）Decomposition of hydriodic acid 2HI→H2+I2,the total reaction is H2S+2H2O+O2→2H2+H2SO4.key steps of the cycle Direct electrolysis of Bunsen reaction products（HI/H2SO4/H2O/toluene mixture）can overcome technical problems such as high temperature of conventional Bunsen reaction and difficulties in product separation,while achieving electrolysis for hydrogen production.Limited,short electrolyte residence time,conversion rate,etc.The microreactor has the characteristics of small size,large specific surface area,easy operation and intrinsic safety,etc.The electrolysis of HI/H2SO4/H2O/toluene two-phase system in microelectrochemical reactor is expected to achieve rapid mixing,efficient mass transfer and precise and controllable process.Based on this,this paper focuses on the flow and mixing characteristics of HI/H2SO4/H2O/toluene two-phase flow in microchannel,numerically simulates the two-phase flow and mixing process in microchannel electrolytic cell,investigates the effects of microchannel structure,fluid properties,and operating parameters on the two-phase flow and mixing characteristics,constructs liquid-liquid non-homogeneous microchannel electrolytic cell,and provides theoretical and technical support for the direct electrolysis of Bunsen reaction products to provide theoretical and technical support,and promote the closure and application of hydrogen and sulfuric acid technologies for resource recovery of sulfur-containing pollutants.The main contents covered in this study and the main conclusions obtained are as follows:（1）In this paper,Ansys-fluent numerical software simulation was selected to investigate the flow and mixing characteristics of the two phases of HI/H2SO4mixed acid and toluene in a serpentine microchannel,using ICEM CFD for structured meshing and a multiphase flow Mixture model in the pre-processing software.The simulated data results were verified by experiments,and the results showed that the standard error and the mean absolute error were within 5%,and the simulation method was feasible.（2）The effects of operating parameters such as fluid inlet mode and flow rate on the mixing characteristics of liquid-liquid two-phase flow of toluene and HI/H2SO4 mixed acid were investigated.The mixing performance of the upper and lower stratified inflow is better than that of the left and right stratified inflow,and the fluid inlet mode has little effect on the differential pressure;under the condition of constant two-phase flow rate ratio,the degree of two-phase mixing shows a trend of increasing and then decreasing with the increase of flow rate,and the highest degree of two-phase mixing occurs at the flow rate of 0.035 m/s;the bend is the main source of local pressure loss;due to the effect of centrifugal force,the causes a velocity gradient of the fluid at the bend,and the fluid remains stratified.（3）The structure of the microchannel is optimized by adding a groove in the straight channel to study the effect of the groove on the two-phase flow and mixing.The addition of recesses increases the fluid flow,decreases the kinetic potential energy,increases the resistance loss along the path,and induces vortices easily on the rear side of the recess,which is conducive to accelerating the two-phase mixing and reducing the mixing length;increasing the height of rectangular recesses leads to an increase in the contact area of the two phases,which can promote the mixing of the two-phase flow,but the pressure loss also increases;reducing the spacing between adjacent recesses leads to an increase in pressure loss;semicircular recesses,due to their special Due to the special curvature of the semicircular recess,the vortex area at the back side of the recess is smaller than that of the rectangular recess,and the pressure loss is correspondingly smaller. |
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