Root culture using a mist culture system and estimation of scale-up feasibility

Normal root of Hyoscyamus niger was cultivated in four different culture systems; a flask, a stirred tank reactor, a mist bioreactor, and a unified mist bioreactor. The scopolamine/hyoscyamine contents of the roots in the various reactor configurations were at similar levels, but the growth rates were different. The dry weight of the root in the flask increased 21·4 times in 25 days, 12·9 times in the stirred tank reactor, and 4·76 times in the first mist bioreactor respectively. This low growth rate in the first mist bioreactor was probably due to limited nutrient supply of the air-carrier method. Root growth increased 9·29 times using the unified mist bioreactor in which mist can be sufficiently supplied without dilution of mist by air flow. It was estimated that a scale-up of over 10 dm³ of reactor volume would not be effective if the air-carrier method were used in a mist culture system.     

城镇污水磁种絮凝-高梯度磁分离处理扩大连续试验研究

在小试研究基础上, 开展了磁种絮凝-高梯度磁分离净化处理城镇污水的扩大连续试验研究。试验结果表明, 该工艺对去除城镇污水中的磷、重金属有特效, 并能同时去除其中的COD_Cr、BOD₅、SS, 出水水质达到或接近国家一级排放标准, 是一种很有发展前途的工艺, 尤其适用于城市小区、小城镇污水处理厂建设、城市大中型污水处理厂增能扩容及出水回用强化处理。     

聚氯乙烯树脂高效组合式干燥工艺数值模拟及工程放大

聚氯乙烯树脂生产装置的具体特点,依据聚氯乙烯树脂的干燥动力学数据,数值模拟了聚氯乙烯高昴组合式旋流干燥装置,经与２．５万ｔ／ａ生产装置对比后发现：数值模拟结果与工厂实测数值基本吻合,说明所建立的数学模型可以较地模拟聚氯乙烯高效组合式旋流干燥装置,同时,以此为基础,设计开发了５万ｔ／ａ生产装置。     

Production of fine lactose particles from organic solvent in laboratory and commercial-scale spray dryers

A laboratory spray dryer and a commercial dryer with a production rate 50 times greater, both using two-fluid nozzles, were used to dry the same formulation from organic solvent. Both dryers generated particles of similar size, with tight particle size distributions (span <2), which varied with atomization gas flow rate, liquid flow rate, and solids concentration. Small-scale results with an external mixing nozzle were fitted to a correlation based on literature recommendations. This also fitted well for the commercial dryer with external mixing, and an internal mixing nozzle gave a tighter size distribution. Hence, successful verification at scale has been achieved.     

A quality by design approach to scale-up of high-shear wet granulation process

High-shear wet granulation is a complex process that in turn makes scale-up a challenging task. Scale-up of high-shear wet granulation process has been studied extensively in the past with various different methodologies being proposed in the literature. This review article discusses existing scale-up principles and categorizes the various approaches into two main scale-up strategies – parameter-based and attribute-based. With the advent of quality by design (QbD) principle in drug product development process, an increased emphasis toward the latter approach may be needed to ensure product robustness. In practice, a combination of both scale-up strategies is often utilized. In a QbD paradigm, there is also a need for an increased fundamental and mechanistic understanding of the process. This can be achieved either by increased experimentation that comes at higher costs, or by using modeling techniques, that are also discussed as part of this review.     

A heat transfer model and supporting experiments to guide the uniform gelation of molecular oleogels during scale-up

The quest for novel vegetable oil structuring strategies has been progressing since the discovery of the deleterious impacts of trans fats. Although oleogelation using bioderived molecular gelators has been proven to be successful as an alternative to traditional hydrogenation methods, efforts are needed to meet the industrial requirements. A major constraint during the fabrication of oleogels is to achieve consistency in physical properties during scale-up. Experiments showed that gelation fails to occur when larger volumes were prepared based on the minimum gelation concentration (MGC) of gelators, determined using the smallest oil volume (1 ml), a general laboratory practice. This observation was consistent with all the molecular gelators used in this study; sorbitol dioctanoate, mannitol dioctanoate, and 12-hydroxystearic acid. To understand this behavior, a mathematical model was developed since gelator network propagation is governed by the cooling rate. The model indicates that maintenance of a minimal thermal gradient via uniform heat dissipation and gelation time is necessary to achieve homogeneous gel propagation across the vial. With these predictions, we hypothesized and confirmed that oleogels with constant surface area-to-volume ratio could result in identical gelation times and consistent physical properties (MGC, melting temperature, melting enthalpy, yield stress, solid phase content, and oil binding capacity) during scale-up.     

工业反应过程的开发方法Ⅺ．炔醛法合成丁二醇反应过程的开发

以炔醛法合成１，４一丁二醇反应的炔化反应过程和加氢反应过程为研究对象，应用工业反应过程开发方法的基本原则，进行炔化反应和加氢反应开发方法的论述，包括确定优选工艺条件、反应器型大的选择和反应器的主要工程问题。从小试、中试、冷漠试验到工业规模试验，为大型装置设计提供依据。     

GAC adsorber design protocol for the removal of off-flavors

This paper investigates the effectiveness of granular activated carbon (GAC) for removing off-flavor compounds of water—geosmin and 2-methylisoborneol (MIB). More specifically, it focuses on the development of an appropriate modeling approach and experimental protocol for the design of fixed-bed GAC adsorbers. Adsorption equilibrium, rate and long-term mini-column studies were conducted on a bench-scale for geosmin and MIB to estimate the equilibrium and mass-transfer parameters required for adsorber modeling. The dispersed flow homogeneous surface diffusion model (DFHSDM) was used for the prediction/simulation of the adsorber dynamics. Scale-up procedures based on dimensional analysis and similitude were employed for the design of full-scale adsorbers from bench-scale adsorbers, and for performance forecasting of full-scale adsorbers under different operating conditions. More importantly, operation and maintenance (O & M) costs were estimated for full-scale adsorbers directed at the removal of off flavor compounds, based on carbon utilization rates and disposal costs. These estimates were obtained for different plant capacities and empty bed contact times (EBCTs).     

PTT合成放大实验及其纺丝性能研究

在聚对苯二甲酸丙二醇酯(PTT)合成的小试研究基础上,进行了在20 L熔融缩聚反应釜中合成PTT的放大实验,并进行了PTT纺丝实验。结果表明:合成得到的PTT特性黏数为0.89 dL/g,端羧基含量为48μmol/g,3,3-氧基二丙醇质量分数为0.46%,玻璃化转变温度为45℃,熔点为228℃。PTT初步达到纤维级别的要求,在400 m/min的速度下能够顺利纺丝,经过2.5倍拉伸后,纤维线密度为96.7 dtex,断裂强度为1.3 cN/dtex,断裂伸长率为97.35%,模量为2.7 cN/dtex。