ANALYSIS OF THREE-PHASE INNER-CIRCULATION BIOLOGICAL FLUIDIZED BED OPERATION FACTORS BASED ON CFD

A mathematical model of gas-liquid-solid three phase inner-circulation fluidized bed was established． The feasibility of fluid dynamics CFD simulation technology applied in gas-liquid-solid three-phase fluidized bed in operation was verified． The effect of the operating factors such as superficial gas velocity and solid loading ratio on gas holdup and liquid circulation velocity was discussed． The results showed that gas holdup firstly increased，then decreased with solid loading ratio continuously going up，and a maximum reached at 13%． When the superficial gas velocity changed in the range of 0 ～ 0. 05 m/s，gas holdup increased with the increase of superficial gas velocity，peaking at 0. 05 m/s． When superficial gas velocity was greater than 0. 05 m/s，no longer gas holdup increased with the increase of superficial gas velocity，but basically remained unchanged． Liquid circulation velocity decreased with the increase of solid loading ratio，but increased with the increase of superficial gas velocity． In terms of gas holdup，liquid circulation velocity as constraint conditions，the fluidized bed reactor was in the best condition with solid loading ratio 13% and superficial gas velocity of 0. 05 m/s．