3300 m~3大型气升式环流反应器数值研究

针对目前机械搅拌餐厨垃圾厌氧发酵罐存在搅拌能耗高、流场混合效果差等问题,课题组提出了气升式环流反应器。采用FLUENT软件对大型气升式环流反应器内气液两相流流场进行数值模拟,研究导流筒直径的变化对反应器内流场、气相体积分数和循环液速的影响。模拟结果表明:反应器内介质形成循环流动时,导流筒内侧沿壁处出现区域小面积环流。改变导流筒的直径及高度对反应器内气相体积分数影响较小,当导流筒直径为2. 5～2. 9 m或导流筒高度为15. 2～15. 8 m时,反应器内液体速率较大,环流效果较好。增大表观气速,反应器内气相体积分数和液体速率均有所增大。文中研究为大型环流反应器的结构优化提供参考。     

新型气升环流反应器用于黄原胶发酵的研究

在对气升环流反应器性能研究的基础上 ,以不同规模的气升环流反应器做了一系列的黄原胶发酵实验 ,并与“标准”机械搅拌发酵罐进行对比 ,发现气升环流反应器能够有效地提高黄原胶的发酵水平 ,缩短发酵周期 ,降低发酵能耗 ,是一种有着广阔应用前景的新型反应器。     

鼓泡式反应器和气升式内环流反应器在废纸脱墨中的应用

在碎浆、洗涤、浮选和二次洗涤四步脱墨工艺中,研究了鼓泡式反应器和气升式内环流反应器对废纸浆的脱墨效果。用脱墨浆白度和墨斑强度来评价脱墨效率。用气升式内环流反应器代替鼓泡式反应器可使脱墨浆白度提高1～4个百分点。墨斑数量减少3％～14％。此外,还研究了在碎浆段用炼油厂Merox工段废水取代NaOH溶液作为碎浆用液的可行性,和NaOH溶液相比,Merox工段废水使废纸浆白度提高更多。这两部分实验表明,工业应用上在碎浆段使用工业废水和在浮选段使用气升式内环流反应器均能获得理想的脱墨效果,且在生产高品质产品的同时降低了投资和运行成本,绿色环保。     

气升环流反应器用于β—胡萝卜素发酵的研究

针对三孢布拉霉菌发酵产β－胡萝卜素的特点，设计了一种新型气升环流反应器，并对操作条件，结构参数与反应器传质特征之间的关系进行实验考察，分析了反应器高剪切区利用流体剪切变稀特性强化传质的原理，３０Ｌ气升环流反应器β－胡萝卜素发酵结果，β－胡萝卜素产量达１７４６￣１８５７ｍｇ／Ｌ。     

气升式生物柴油反应装置设计与试验

设计了一种用于酯交换制备生物柴油的新型气升式反应装置。通过理论分析和试验,确定了反应器降液管高径比值（H/D）为10.70,分布器孔径在4～5mm之间。与传统机械搅拌式反应器相比较,采用气升式反应器制备脂肪酸甲酯转化率提高了8.5%,反应时间缩短0.5h,提高了原料转化率,降低了生产成本。     

气升式反应器在L-苯丙氨酸发酵产酶过程中的应用

针对L 苯丙氨酸的酶法制备体系 ,研究了内循环和外循环气升式反应器在L 苯丙氨酸产酶发酵过程中的应用。实验发现 ,与标准机械搅拌罐相比 ,采用气升式反应器发酵产酶 ,转氨酶酶活分别提高了 2 0 %和 1 0 % ,产酶周期也相应缩短。     

气升式生化反应器提高衣康酸产酸率的研究

测定了气升式生化反应器的相关参数,建立了相应的传氧方程。采用不同生化反应器进行衣康酸发酵．结果表明，采用气升式生比反应器与机械搅拌罐相比，提高产酸14％，提高转化率16％，生产能力提高38％。     

流化床生物膜反应器用于酵母菌体培养

研究了流化床生物膜反应器用于酵母菌体培养的结果，发现在气升式反应器中加入载体，形成流化床生物膜反应器，可以进一步提高反应器的传氧速率、间歇培养的菌体浓度和连续培养的生产强度。     

环流筛板塔式生化反应器研究

本文针对内环流反应器在通气发酵过程中应用时存在的一些问题,设计了一种在导流筒上面设多段环流筛板的新型塔式生化反应器,内径D=200mm,总高H=2500mm;并对其流动特性、气含率和传质系数进行了研究,[用压差法测定了全塔及导流筒内的气含率εc,用Na_2SO_3—空气氧化法测定了传氧系数k(?)、气液相界比表面积a(524-1224m-1)及容积传质系数k_La(1171-3278h~(-1)],得出了这种反应器中气含率εc_1,相界面比表面积a和传氧系数k(?)的关联式: 此外,还得出了这种反应器的最佳板间距(H_1=2h_1)和最佳操作气速(Uc=6.2cm/s),推导出筛板环流筒长度的计算式:供放大设计时参考。     

户外管式光生物反应器培养发状念珠藻细胞

采用液体悬浮培养方式,实现了户外条件下160 L和300 L管式光生物反应器(φ50和φ110)对发状念珠藻细胞的培养,培养液pH通过酸度在线控制系统控制在8.0~8.5之间,管道内藻液流速为0.2~0.3 m/s。培养液温度通过淋水装置控制在25~28℃。在光照充足条件下,经过8d培养,160 L管式生物反应器中发状念珠藻的生物量OD420值由0.325增加至0.907,300 L管式光生物反应器的生物量OD420值由0.37增加至0.533,而室内气升式光生物反应器OD420值由0.306增加至0.775。通过与室内80 L气升式光生物反应器培养对比发现,管式光生物反应器最终收获的发状念珠藻藻粉中蛋白质含量为46.8%,荚膜多糖含量为17.8%,均高于室内气升式光生物反应器深层液体悬浮培养下的37.8%和5.6%。结果表明,发状念珠藻细胞适于户外管式光生物反应器条件下的培养。     

Submerged culture of Tricholoma matsutake mycelium in bubble column fermentors

Submerged culture of Tricholoma matsutake mycelium was carried out using two bubble column fermentors, a standard bubble column and an external-loop airlift column. The effects of the aeration rate and column type on culture performance in terms of the mycelia morphology, glucose consumption, cell yield, and growth rate were investigated. Morphologically, three types of pellets-large spherical, small spherical and filamentous-were observed depending on the aeration rate. On the whole, the standard bubble column gave a higher cell yield and a better growth rate than the airlift type. The maximum cell yield and growth rate attained at a superficial air velocity of 0.38 cm/s were superior to those obtained in a flask culture, suggesting that the bubble column fermentor has the potential to be used for submerged culture of T. matsutake.     

Applying ratio control in a continuous granular reactor to achieve full nitritation under stable operating conditions

A ratio control strategy was implemented in a continuous granular airlift reactor to achieve and maintain 100% partial nitrification to nitrite (i.e., full nitritation). The control strategy was designed to maintain a constant ratio between the dissolved oxygen (DO) and the total ammonia nitrogen (TAN) concentrations (DO/TAN concentration ratio) in the reactor bulk liquid. The experimental results demonstrated the feasibility of full nitritation of a high-strength ammonium wastewater with a granular reactor operating in continuous mode, when implementing a suitable control strategy. The effect of the DO/TAN concentration ratio on partial nitrification was fast and reversible, upon switching from complete to partial nitrification, despite the presence of nitrite-oxidizing bacteria (NOB) in the granule. Even at a DO concentration as high as 7 mg of O(2) L(-1), full nitritation was obtained, decoupling the achievement of partial nitrification in continuous granular reactors from low DO concentrations. Inhibition of NOB by free ammonia was found to contribute poorly to the achievement of partial nitrification. An extremely high volumetric nitrogen loading rate was achieved (6.1 g of N L(-1) day(-1) at 30 °C), demonstrating that very compact reactors are applicable to nitrogen removal via nitrite.     

Kojic acid production in an airlift bioreactor using partially hydrolyzed raw corn starch

In a culture of Aspergillus oryzae MK-107-39 in a 3-l airlift bioreactor, kojic acid was not produced when glucose/wheat germ medium (GM1) was used. However, when a jar fermentor was used, the kojic acid yield was high. A suitable medium for culture in an airlift bioreactor consisting of partially hydrolyzed corn starch and a small amount of corn steep liquor (CSL) (SM1) was selected. In the cultivation in the airlift bioreactor using SM1, nearly 40 g/l of kojic acid was produced, which was the same as the amount produced in the jar fermentor containing GM1. The optimum aeration rate for the airlift bioreactor was 2.0 vvm (0.66 cm/s of superficial linear velocity (Vs)). The cost of SM1 using the airlift bioreactor was reduced to 40% that of GM1 using the jar fermentor. Furthermore, the energy cost of kojic acid production using SM1 in the airlift bioreactor was less than one-fourth of that for the jar fermentor using GM1.     

Effect of capsule circulation velocity on production of L-lysine by encapsulated Corynebacterium glutamicum in an airlift bioreactor

The effect of capsule circulation velocity and volumetric oxygen transfer coefficient on the production of L-lysine by encapsulated Corynebacterium glutamicum in an airlift bioreactor has been evaluated. A larger oxygen supply in the airlift bioreactor caused a more than 58% increase in L-lysine productivity compared to that in a shaking flask incubator. The quantity of L-lysine produced during 5 h of cultivation in the airlift bioreactor was suggested to increase with increasing circulation velocity of the capsule in the bioreactor rather than with an increase in volumetric oxygen transfer coefficient.     

Production of epsilon-polylysine in an airlift bioreactor (ABR)

This paper deals with studies on epsilon-poly-L-lysine (epsilon-PL) production in an airlift bioreactor (ABR) using Streptomyces albulus S410 (S410) to minimize the production cost including the downstream processing of epsilon-PL. In a 5-l ABR, 30 g/l of epsilon-PL was produced with a power consumption of 0.3 kW/m3, the production level being similar to that in a 5-l jar fermentor with a power consumption of 8.0 kW/m3. Furthermore, the leakage of intracellular nucleic acid (INA)-related substances into the culture broth in the ABR was less than that in the jar fermentor. Due to the high-level power consumption (8.0 kW/m3) in the jar fermentor, the morphology of the cells changed from the pellet to filament form due to the extensive shear stress arising from continuous agitation, thereby increasing the leakage of the INA-related substances into the culture broth. This suggested that ABR would have an advantage in the low-cost production of epsilon-PL over stirred tank type reactors (STR).     

气升式发酵罐发酵黄原胶的动力学

利用黄单孢菌研究了在50L气升式发酵罐发酵黄原胶的动力学,在logistic方程和Luedeking Piret方程的基础上,建立了两步发酵黄原胶的动力学模型,并对模型和实验数据进行了比较,进一步在200L相似结构的气升式发酵罐中的试验表明,该模型能较好的对发酵动力学进行描述.     

Degradation of waste gas containing toluene in an airlift bioreactor

Suspension microorganisms in an internal-loop airlift bioreactor were utilized to treat waste gas containing toluene. The working volume of the reactor was 35 L, and the biomass concentration was 3 kg/m3. The gas pollutant flowed into the reactor from the bottom; it then transferred from the gas phase to the liquid phase and was degraded by the microorganisms suspended in the liquid phase. The microorganisms were able to degrade 50-90% of the inlet toluene when its concentration was from 0.5 to 10 g/m3, and the superficial gas velocity ranged from 0.15 to 1.23 cm/s. A comprehensive mathematical model was also developed to describe the overall degradation process of toluene in the internal-loop airlift bioreactor. The overall degradation process included gas flow, gas-liquid mass transfer, flow and dispersion of the liquid phase, and microbial kinetics. The hydrodynamic properties including the gas and liquid superficial velocities, the gas holdup, the volumetric mass transfer coefficients of toluene and oxygen, and the microbial kinetics were obtained for this model. The substrate inhibition theory was used to simulate the microorganism growth kinetics, and its kinetic constants were obtained experimentally. The penetration theory was used to predict the volumetric mass transfer coefficient. And the drift-flux theory was used to predict the hydrodynamic properties in each section (riser, gas-liquid separator, downcomer, and bottom) of the airlift bioreactor. The concentration distributions of toluene and oxygen in the airlift bioreactor and the removal efficiency of toluene predicted by the mathematical model agreed well with the experimental data.     

Optimization and scale-up of L-lactic acid fermentation by mutant strain Rhizopus sp. MK-96-1196 in airlift bioreactors

We determined the optimum culture conditions such as inoculum size, initial starch concentration, pH during the fermentation and aeration rate for L-lactic acid production by Rhizopus sp. MK-96-1196 in a 3-l airlift bioreactor. More than 90 g/l of L-lactic acid was produced from only partially enzymatically hydrolyzed corn starch with a production rate of 2.6 g/l/h and a product yield of 87% based on the starch consumed under the optimum conditions in the 3-l airlift bioreactor. Scale-up from the 3-l to a 100-l airlift bioreactor for L-lactic acid fermentation was carried out using V(s)(cm/s) as a scale-up criterion. The production rates and yields of L-lactic acid in both bioreactors appeared to be fairly well correlated with k(L)a (1/h).     

Production of L-lactic acid from corncob

The optimum temperature, initial pH, amount of added enzyme and substrate (corncob) for the hydrolysis of corncob by Acremonium cellulase were 35 degrees C, 4.5, 10 u/g-corncob and 100 g/l, respectively. Under the optimum conditions, more than 55 g/l of reducing sugars were hydrolyzed from 100 g/l of corncob to 34 g/l of glucose and 12 g/l of xylose based on dried corncob. More than 25 g/l of L-lactic acid was produced from this enzymatic hydrolyzate and less than 5 g/l of xylose remained in the 3-l airlift bioreactor. The production of L-lactic acid by simultaneous saccharification and fermentation (SSF) was also carried out in the 3-l airlift bioreactor using Acremonium thermophilus (cellulose-producer) and Rhizopus sp. MK-96-1196 (lactic acid-producer). More than 24 g/l of L-lactic acid was produced from 100 g/l of untreated raw corncob.     

High efficiency production of astaxanthin in an airlift photobioreactor

In photobioreactors, photosynthetic microorganisms are exposed to certain light/dark cycles caused by light intensity distribution and mixing inside the photobioreactor. In this study, Haematococcus pluvialis was cultivated in an airlift and a bubble column photobioreactor, and the cell growth and astaxanthin production were compared to clarify the effects of liquid circulation.