A Study On The Flowing Ang Mixing Feature Of A Double Loop Airlift Bioreactor

Airlift reactor has been widely used in chemical industry, biological chemistry for their simple construction, good mixing ,good heat conducting performance, and easy to be operated compared with stirred tanks. It has been extensively studied by scholars at home and abroad, including trying to evaluate its hydrodynamics performance and transmitting capability from material character, operation condition, and constructions of the reactor.Jet loop reactor(JLR) is a kind of multiphase reactors with high-efficient heterogeneous transmission performance, simple device structure, high heat and mass transfer rates, well mixing effects, low energy consumption and easy to be operated etc. It has been used in biology engineering and chemical environment industry extensively.Most research of JLR's performance is focused on aerobiosis course. More than 70 percent of all the reactors studied were slightness, with ratio of height to diameter about 7-12. Focal points were particularly emphasized on mass transfer rates between gas and liquid and the time of gas held up. Few reports about the anaerobic reactors with low ratio of height to diameter can be found.ALR has already been adopted in a large amount in the anaerobic fermentation, but fewer can be found during anaerobic fermentation In anaerobic fermentation, for example alcoholic fermentation, what are used more often present are still traditional large pots without blender apparatus. The overall characteristic of this kind of reactor is its simple constructions and of low ratio of height to diameter (often H/D=1.1:1). With the development of large-scale production, problems existing in its applications become increasingly day by day. While applied to alcohol production, large-scale pot is apt to accumulate materiel, easy to infect other bacteria and often of heavy concentration gradient. At the same time, materiel accumulation will occupy most effective space which tends to shorten fermentation time, cause waste of raw materials and reduce production rate alcohol.While applied JLR to anaerobic fermentation, material can be stirred by insidecirculation of gas and liquid to reduce held up and infect other bacteria. During the course of jetting, gas and liquid are mixing strongly and shear strength becomes even heavy. Thus pays for dispel suppress membrane of metabolite near yeast cell. Consider requests of the development trend of large scale production meanwhile, outside circulation should be put into account in order to realize outside cooling on the basis of circulating inside, therefore, inside complicated cooling wash device could be reduced as a result, effective pot hold would increase. Meanwhile the flux of fluid and gas will be convenient to regulate when JLR are adopted. The reactor's structure becomes simple and easy to realize continuous production. Besides, in anaerobic fermentation not large amount of gas is needed, therefore investment for additional equipment will be reduced to some extent.Considering the character of anaerobic reaction, one kind of double loop jet-air lift bioreactor is applied in anaerobic fermentation. Flow and mixing characteristic of one kind of double loop air lift bioreactor with low ratio of height to diameter ( H/D=1.67) are studied in this paper. How changes of diversion tubes diameter, flux of gas and outside circulation influence the total gas hold up, mixing time, liquid circulation speed and consumption of unit volume material are mainly studied in this paper. Considering that jet-inhale course consume more energy and of high loss, two kinds of different introducing ways of gas: inhale gas and ventilate gas are adopted. Flow and mixing effect of the two are compared. Economic contrast of them is carried on too, to offer for industry's practical application. The experiment includes two circulations, inside and outside circulation.Air and water were used as gas and liquid phase; the volume ratio of gas to liquid is 0.01~0.1m3(G)/min/ m3 (L); volume of outside circulation flux is: ventilate gas: 2~6m3/h; inhale gas: 3~5m...