改进型气升式反应器能耗的研究

Study on Energy Dissipation in Modified Airlift Bioreactor

首次研究了操作条件和反应器结构(导流筒直径和静态混合元件数)对改进型气升式反应器功耗的影响。结果表明,优化导流筒结构可以实现节能降耗。曝气量相同时,在导流筒直径为4.0cm,静态混合元件数为39的条件下,改进型反应器的功耗最小,比普通反应器平均降低23.6%。达到相同供氧能力时,在导流筒直径为5.5cm,静态混合元件数为13的条件下,改进型反应器的功耗最小,比普通反应器平均降低43.9%。在改进型反应器中,升流区功耗最大,占70%～80%;底隙区次之,占20%左右;气液分离区最小,小于10%;降流区功耗可以忽略不计。最大体积功耗出现在底隙区。升流区是解决反应器能耗问题的重点。

The effects of operational variables and reactor configurations （e. g. diameter of draft tube and the number of static mixers） on energy loss in modified airlift bioreactor were investigated at the first time. The results showed that improving the structure of draft tube could reduce energy loss in the bioreactor. When the diameter of draft tube and the number of static mixers were 4.0cm and 39, respectively, the total energy loss in the modified bioreactor was the least among all the configurations and 23.6% less than that of the conventional counterpart at the same air flowrate. The energy consumption for aeration was the smallest （43.9% less than that of the conventional counterpart） when the diameter of draft tube and the number of static mixers were 5.5cm and 13, respectively. The highest energy dissipation （70% ~ 80% ） occurred in the riser, the bottom zone （about 20% ） took the second place and the separator （less than 10% ） took the third place. The energy dissipation in the downcomer was neglectable under the conditions in the research. When the energy loss per unit volume was considered, bottom zone stood the first place. It was implied that the riser was the most important zone to cut down the energy loss of the bioreactor and some attention should also be paid to the bottom zone.