The Flow Field Simulation Analysis And Overall Optimization Design Of The Titanium Steel Composite Plate Acetic Acid Distillation Tower

In view of the problems in the actual production of acetic acid distillation tower,such as poor corrosion resistance,gas-liquid leakage,large pressure difference in the tower and entrainment of mist on the top of the tower,the flow field simulation analysis of the liquid distributor and the cylinder in the variable diameter section was carried out based on the structural factors affecting the distillation efficiency,and the overall structure was optimized according to the flow field simulation analysis structure.The main work and research results of this paper mainly include the following aspects:(1)The structural factors affecting the distillation efficiency are analyzed,including the effect of gas-liquid distribution of the liquid distributor,the effect of pressure difference caused by the variable diameter section of the cylinder,and the effect of the demisting efficiency of the wire mesh demister structure.Based on the comparative analysis of the economy and technology of different stainless steel and titanium materials,the base material is Q345 R,and the cladding material is pure titanium composite plate.This material has excellent corrosion resistance,high hardness and low cost.(2)The gas-phase flow field of three kinds of liquid distributor structures,i.e.distributor structure,inclined plate structure and hole structure,is simulated.The conclusion is as follows:the uniformity of the symmetrical distribution of the gas phase in the distributor is higher than that of the unidirectional distribution;for the collector structure,the corresponding minimum nonuniformity mainly exists at the beginning of the gas phase distribution.The opening rate of gas channel can not reflect the gas distribution uniformity,but the gas outlet structure of distributor can be consistent with the actual standard,which can significantly improve its distribution uniformity.The effect of empty tower gas velocity on the nonuniformity of axial gas flow field in different structures is not obvious.(3)The distribution of the internal pressure of the distillation column in the process of gas-liquid two-phase contact with the change of the inclination angle ? and the height h of the variable diameter section is simulated and calculated,and the following conclusions are drawn:when the height h of the variable diameter section remains unchanged,the internal pressure of the distillation column increases with the increase of the inclination angle ? of the variable diameter section;when the inclination angle of the variable diameter section remains unchanged,the internal pressure of the distillation column is affected The pressure increases with theincrease of the height h of the variable diameter section,and finally the appropriate angle ? = 9? and the height h of the variable diameter section is 1423 mm.(4)Based on the results of flow field analysis,the overall optimization design of acetic acid distillation column was carried out.According to the numerical simulation results,the inclined angle ? of the cylinder in the variable diameter section is designed as 9 ° and the height h is designed as 1423 mm.The structure of the wire mesh demister is improved,and the connection structure of tower body and flange,pressure gauge,thermometer and main connecting pipe is designed to prevent leakage.The stability of the shell is checked,and the calculation length,external pressure stress coefficient and allowable external pressure stress are determined.