基于CFD的三相内循环生物流化床操作参数影响的分析

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

建立了气-液-固三相内循环流化床的数学模型,验证了流体力学CFD模拟技术应用于气、液、固三相流化床操作中的可行性,探讨了表观气速和固体装载率等操作参数对气含率以及液体循环速率的影响,结果表明,随着固体装载率的增大,气含率先增大后减小,在13%处取得最大值。当表观气速在0~0.05 m/s时,气含率随着表观气速的增大而增大,在0.05 m/s处达到最大值,表观气速大于0.05 m/s时,气含率不再随着表观气速的增大而增大,而是基本保持不变。液体循环速率随固体装载率的增大而减小,随表观气速的增大而增大。在以气含率、液体循环速率作为约束条件的情况下,流化床反应器的最佳固体装载速率为13%,最佳表观气速为0.05 m/s。

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.