Study On Gas Solid Two Phase Flow And Drying Characteristics In Spouted Bed With Gas Stream

Spouted bed with special characteristics of gas-solid two-phase flow,good heat and mass transfer characteristics,has been widely used in the fields of medicine,energy and chemical industry,spouted bed has a pivotal position especially in the dry industry,but with the continuous improvement of product quality requirements,independent spouted bed drying has been unable to meet the demand.In view of the advantages and disadvantages of spouted bed and air pipe drying,the airflow drying pipe and spouted bed are organically combined together in this paper,which makes full use of the advantages of both of them,so as to complement the shortcomings,the experiment platform of airflow-spouted bed is built.The characteristics of gas-solid two-phase flow in spouted bed are studied by experiments.The research shows that the gas velocity,bed height and particle size has an important effect on the flow characteristics of spouted bed,in addition,spouted bed is required for the particle size of the working material,better performance can be achieved only when the requirements are met.The suitable particle size for the equipment is in the range of 2 mm~ 3 mm.The results also show that the optimum bed thickness is 150 mm,and there is a certain range of gas velocity under different particle size and bed thickness.In addition to the study on the flow characteristics,we also studied on the performance of equipment drying by experiment,air drying and spouted bed with gas stream drying were analyzed by experiment.The results show that the air drying can only remove the water of the material surface,while the water inside the material needs to be removed by spouted bed.This shows that the spouted bed with gas stream make full use of the conveying capacity of air drying while removing the water of the material surface,the method solves the problems that the spouted bed is likely to have a reunion,a dead bed,etc.further the spouted bed was used to dry the material moisture and improves the quality of the drying product.The optimum working conditions of intermittent operation of drying is: gas velocity is 13.81 m/s,bed thickness is 150 mm,drying temperature is 150 ?;the optimum working conditions of continuous operation: gas velocity is 13.81 m/s,bed thickness is 150 mm,feeding rate is 50 kg/h,drying medium temperature is 200 ?.Due to the limitation of the experiment,numerical simulation was also carried out in this paper,the characteristics of gas-solid two-phase flow in the spouted bed was studied by simulation,including the velocity distribution of particles and gas in the bed,the radial distribution of particle volume fraction,and so on.The flow characteristics of gas-solid two-phase flow in the equipment are revealed.