Experimental Research On Power Consumption And Mixing Performance Of Complex Rheological Systems

In some production process of catalyst,the state of reaction material in the stirred tank will change from the powder to the system of complex rheological properties such as wet powder and slurry.Due to the change of the rheological properties of the material,the torque and stirring power of the stirrer change significantly,so it's necessary to study the stirring characteristics in this kind of complex rheological system.In this paper,glass balls or glass beads with average diameter of 150?m,1.6mm and 5mm were used as experimental solid phases in the plexiglass stirred tank with diameter of 0.284 m and 0.476 m,respectively.SBT-4,SBT-2 and PBT-2,single snail helical ribbon and Paravisc impeller and other impellers were studied about stirring power.The experimental results show that the torque increases with the increase of the rotational speed and the increase of the H/T,and the influence with H/T is more significantly.For the same powder material,the stirring torque is varies with particle size;the direction of the friction on the torque have a certain impact to the stirring torque.When the glass beads were agitated with double helical ribbon,single helical ribbon and Paravisc impeller,the unit volume work Pv was linearly related to the speed N and the material filling height H/T,and the correlation are respectively Pv=4.224N(H/T),Pv=3.2025N(H/T)and Pv=5.595N(H/T).When the water-containing powder is stirred,the torque fluctuation is obvious.The maximum value can reach 300%of the dry powder stirring when the water was added some times,and the torque peak is reached only in a short time when the water is added in.The maximum value reaches nearly 500%of the dry powder agitation after the water was added in one time;when the amount of water exceeds the porosity of the powder layer,the moisture content changes from the dispersed phase to the continuous phase,and the torque value decreases to close to the dry stirring.In addition,this paper also deals with a pilot project of ?-molecular sieves,including water tests for pilot plants and 50%,80%load producting.The torque of the pilot mixing device is compared with that of the cold mold experiment,and the similar torque regular pattern is found.