Physical Simulation On Fluidization Quality In New Type Tilting Agitated Fluidization Ironmaking Process

Due to the uneven distribution of gas and solid,abnormal fluidization phenomena such as surging,channeling,particle sticking and even dead bed will be caused in the actual production process of the fluidization ironmaking process.Furthermore,the heat and mass transfer efficiency and reduction rate of iron ore fines will be reduced,which is not conducive to the stable operation of the fluidized bed reactor and prone to accidents.To deal with the problem of the uneven gas-solid distribution in the process of fluidization ironmaking,the performance of the fluidized bed should be improved first.The performance of the fluidized bed depends on the bubble behavior largely.It makes the bubbling fluidized bed run more efficiently to reduce the bubble size.Two zones of fluidized bed were divided as following:bottom zone where the distributor plays a major role,agitated fluidization zone where the agitator has a positive effect on fluidization.Physical simulation experiments are carried out in different zones to find the best equipment parameters.The relationship between fluidization quality and its main influencing factors is established.The following innovative results were achieved:(1)A physical simulation experiment platform is designed and developed for the actual production process of the fluidization ironmaking process.It includes traditional fluidized bed,top agitated fluidized bed,tilting agitated fluidized bed,gas control system,pressure measurement system and optical analysis system.(2)In the bottom zone,the fluidization quality of the fluidized bed can be improved by adjusting the perforated ratio of the distributor.The results show that the fluidization quality of the whole bed can be optimized with the decrease of the perforated ratio of the distributor,especially in the middle and lower part of the fluidized bed.When the perforated ratio of the distributor is 0.31%,there is no bubble in the middle and lower part of the fluidized bed.The fluidization quality is good,which presents the particulate fluidization.(3)In the agitated fluidization zone,the fluidization quality of the fluidized bed can be improved by adjusting the agitation speed,agitation mode,agitator,agitation direction and agitator diameter.The results show that agitator can force the particles into the bubble,break the big bubble and improve the fluidization quality.With the increase of agitation speed and agitator diameter,the fluidization quality in the agitated fluidization zone can be greatly improved.Tilting agitation,three-broad-blade propeller and forward agitation have better effect on improving fluidization quality.(4)Based on the dimensional analysis of the fluidization quality(standard deviation of pressure drop fluctuation in the whole fluidized bed)of the new type tilting agitated fluidized bed(three-broad-blade propeller,forward agitating and agitator height of 250 mm),the empirical formula of fluidization quality in the new type tilting agitated fluidized bed as follows:(?)(5)According to the obtained quasi equation,the influence of agitation speed,perforated ratio of distributor,gas flow and static bed height on the standard deviation of pressure drop fluctuation in the whole fluidized bed is analyzed theoretically.And the empirical formula is shown below:(a)Effect of perforated ratio of distributor on fluidization quality in the new type tilting agitated fluidized bed,σpd=4.83×102N-0.120φ0.223(b)Effect of gas flow on fluidization quality in the new type tilting agitated fluidized bed,σpd=4.49×107N-0.120Q2.12(c)Effect of static bed height on fluidization quality in the new type tilting agitated fluidized bed,σpd=1.06 ×103N-0.120Hp1.72...