Structure Optimization Of Oxidation Tower For Preparing Hydrogen Peroxide By Anthraquinone Method

Oxidation tower is the key equipment for preparing hydrogen peroxide by anthraquinone method.It is mainly responsible for the oxidation of hydrogenated liquid to produce hydrogen peroxide.Aiming at the problem of low oxidation yield in the existing empty tower oxidation tower,this paper analyzes the influencing factors of oxidation yield,carries out the simulation analysis of gas velocity uniformity of gas distributor and the two-phase flow of axial liquid velocity and gas holdup in the oxidation tower,and optimizes the overall structure according to the simulation analysis results.The main work of this paper is as follows:(1)According to the working conditions of the oxidation process for preparing hydrogen peroxide by anthraquinone process,the influencing factors of oxidation yield of anthraquinone oxidation tower were analyzed,including the dispersion effect of gas distributor and the influence of axial back mixing of liquid phase.By comparing and analyzing the structure and application scope of various gas distributors,the multi-loop structure is selected as the gas distributor of the oxidation tower in this paper According to the causes of liquid phase axial back mixing,the influence of liquid phase axial back mixing on oxidation yield and the measures often taken by the industry for liquid phase back mixing are analyzed.In this paper,the horizontal segmentation method is used as the simulation object.(2)The gas velocity uniformity was numerically simulated for the dispersion effect of the gas distributor.According to the distribution of the gas flow field in the gas distributor,the influence of changing the diameter of the distribution pipe and the diameter of the distribution hole on the gas velocity uniformity of the nozzle is analyzed.It is concluded that when the diameter of the distribution pipe changes positively,the gas velocity uniformity of the gas distributor is better than that of the reverse change.When the aperture of distribution hole changes in reverse direction,the effect of gas velocity uniformity of gas distributor is better than that of positive change.However,the gas velocity uniformity of the gas distributor can be effectively improved by changing the diameter of the distribution pipe and the aperture of the distribution hole.(3)In order to explore the liquid phase backmixing condition in oxidation tower,two flow parameters,local gas holdup and axial liquid velocity,were analyzed,and the influences of axial radial position,apparent gas velocity and internal components were studied.It is concluded that local gas holdup and axial liquid velocity increase with the increase of apparent gas velocity.The local gas holdup increases with the increase of h/D height in axial position and decreases with the increase of r/R in radial position in radial direction.With the addition of internal components,the local gas holdup is distributed more evenly in the radial position.The axial liquid velocity increases first and then decreases with the increase of h/D height in axial position.There are ascending and descending areas in the radial position of liquid,and the turning point in the direction of liquid movement is between the radial position r/R=0.7-0.8;With the addition of internal components,the turning point in the direction of liquid movement moves toward the wall,the circulation scale of liquid phase becomes smaller,and the degree of liquid phase back mixing decreases.(4)Based on the results of flow field analysis and specific working conditions,the structure optimization design of anthraquinone oxidation tower was carried out.The gas distributor is designed to change the diameter of distribution pipe and the diameter of distribution hole,and the vertical superimposed cross V-shaped internals are designed to improve the axial back-mixing problem in oxidation tower.Optimize the design of other key parts of the oxidation tower,and design a gas-liquid separator with multi-directional folded plate structure to reduce the pressure of subsequent separation equipment and rationally use the excess space at the upper part of the tower;The heat exchange device adopts a detachable and built-in three-type structure,which can not only take away a large amount of reaction heat,but also facilitate maintenance,disassembly and assembly.