Numerical Simulation Of Gas-Liquid-Solid Three Phase Flow In Bubble Column

The study of the fluid dynamics behavior of the gas-liquid-solid three-phase fluid in the bubble column has a guiding significance in the optimization of the actual industrial conditions,and numerical simulation can better reveal the flow characteristics of the three-phase flow from the microscopic level.By the analysis of the simulation process involved in the model,the appropriate numerical simulation model and parameters,such as the Eulerian three-phase flow model and Population Balance Model,were selected,then numerical simulation was carried by using Fluent,and the three-phase flow system composed of air-water?absorbent?-solid phase sulfur was discussed in the cylindrical bubble column and Chelated iron desulfurization commonly used fan-shaped bubble column under the condition of cocurrent flow.Finally,we got the variation trend of gas holdup and sulfur particle under different conditions.The simulation results show that the total gas holdup in the cylindrical bubble column is related to superficial gas velocity,superficial slurry velocity and sulfur holdup,but not to the form of the distributor.Based on the simulation results of the total gas holdup in the cylindrical bubble column,the least squares method was used to simulate the relationship between the total gas holdup and the effect factors.Finally,get the expression:?=0.495U_G^0.45U_L^-0.131?-V_S?^0.22.Comparing the influence relationship of the total gas holdup with the superficial gas velocity in the bubble column based on the reported data,the rationality of the simulation numerical model and the model parameter selection was confirmed.At the same time,the simulation results show that under different superficial gas velocity and slurry speed,the local gas holdup is gradually decreased with the increase of the height on the axial section of the tower,and it is high at the center and low at the wall on the radial section of the tower,and the increase of the superficial gas velocity or the slurry speed is good for the uniform distribution of the gas holdup in bubble column.The simulation results show that the sulfur volume holdup and sulfur particle velocity on the axial section from the liquid inlet to the outlet in the cylindrical bubbling tower is reduced with increasing of the tower height;on the radial section,the sulfur volume holdup is decreased with increasing of the tower radius.The increasing of the superficial gas velocity and superficial slurry velocity can increase the speed of the sulfur particles,and also make the distribution of the sulfur volume holdup more uniform in the bubble column.In the fan-shaped bubble column,the gas holdup,sulfur volume holdup and sulfur particle velocity distribution are similar to those of the cylindrical bubble column,but due to the irregularities of the fan-shaped bubble culumn,high gas holdup prefers to be at the side with a smaller fan radian.There is sulfur deposition at the bottom of the bubble column,the increase of the superficial slurry velocity is help to slow the sulfur deposition at the bottom of the bubble column.If the liquid inlet is set under the distributor,the problem of the sulfur deposition at the bottom can also be greatly retarded,and the relative vertical distance of the liquid inlet and the distributor plays a key role in preventing the sulfur deposition at the bottom of the bubble column.In the fan-shaped bubble column,the appropriate bottom inlet height is the key to prevent the sulfur deposition at the bottom of the bubble column.Moreover,the tower height has an important effect on the total gas holdup in the bubble column.The total gas holdup decreases with the increase of the tower height,and the decrease range slows down gradually,but the tower height has little effect on the deposition of sulfur particles at the bottom of the bubble column.