Scale-up methodologies for Escherichia coli and yeast fermentation processes

Scale-up techniques from the literature have been compiled and reviewed for applicability to Escherichia coli and yeast processes. The consistency of design and operating parameters for the pilot scale vessels in an existing fermentation pilot plant, ranging in nominal volume from 100 l to 19,000 l, was established and compared favorably with approaches found in the literature. Differences were noted as a function of parameters such as fermentor scale, vessel geometry, agitator type/size and ungassed/gassed power input. Further analysis was conducted using actual fermentation data for historical and recent development processes collected over a 10-year-period, focussing on operating conditions at peak culture oxygen uptake rates. Scale-up estimates were performed based on geometric similarity, agitator tip speed, gassed power per unit volume and mixing time. Generally, scale-up calculations from the 280 l scale were most similar to the parameters of installed equipment. Scale-up from the 30 l laboratory scale typically underpredicted parameters with scale-up from the 280 l scale being most appropriate. The 19,000 l fermentor installation was notably different in geometric similarity from the 280 l-1900 l scales since its design was meant to accommodate a wide range of operating volumes. Analysis of historical and recent processing performance was conducted for single cell bacterial or yeast fermentations which challenged peak operating conditions of the fermentors. Identification of key issues associated with scale-up for these specific pilot plant vessels was believed to be critical to efficient process development, clinical material production, and expected process transfer to a manufacturing facility.     

中国喷射式浮选机研发的简要回顾

简要回顾了半个世纪以来中国喷射式浮选机的研发历程,从始于模仿美国的旋流式浮选机,到近年在美国三座选煤厂成功使用的喷射式浮选机,历经了第一代喷射旋流式浮选机,第二、三代喷射式浮选机的阶段。分析了喷射式浮选机的放大原则,并以FJCA36型喷射式浮选机为例,介绍了其充气搅拌性能指标和工艺效果指标。     

对XY型矿浆预处理器工作情况简要分析

针对XY系列矿浆预处理器工艺效果及其叶轮工作情况进行了简要分析,指出该系列大型设备工艺效果不佳的主要原因是未按弗劳德数相同的准则而按搅拌叶轮线速度不变的原则进行相似放大所致。     

Design of a pilot-scale microwave heated chemical vapor infiltration plant: An innovative approach

A hybrid Microwave-assisted Chemical Vapor Infiltration (MW-CVI) pilot plant to produce silicon carbide-based Ceramic Matrix Composites was designed, built and setup, as a part of the European project HELM. Being different from the existing lab-scale MW-CVI equipment, this pilot plant was designed with the idea of a further industrial scale-up.In order to enable the infiltration of the large samples of interest in industrial applications, the reactor was designed with the internal microwave cavity acting as an overmoded resonator at the frequencies of interest. The designed pilot plant allowed proper microwave heating of cylindrical samples of diameter doubled with respect to typical lab-scale preforms, with reproducible operating conditions in terms of transmitted/reflected power. First infiltration trials resulted in an average reaction efficiency of 25 % with the desired inside-out silicon carbide infiltration. The main steps of the design and the results of the first infiltration tests are discussed in this paper.     

大型高效轴流式搅拌装置

本文介绍了一种适合于大型化的高效轴流式搅拌器的开发及工业应用。     

催化裂化装置沉降器粗旋结构设计探讨

通过FLUENT 6.2流体计算软件,采用雷诺应力模型(RSM)对直径500 mm、三种不同升气管/料腿直径组合的粗旋气相流场进行了数值模拟,分析了升气管和料腿长度改变以及尺寸放大对粗旋流场和性能的影响。模拟结果表明,粗旋流场同普通旋风分离器流场的区别主要在于轴向速度和升气管、料腿内的流场分布;升气管直径大于料腿直径的结构有利于减少由料腿排出的气体量,从而缩短粗旋排出的气体在沉降器内的停留时间,这是粗旋设计的关键;升气管、料腿长度改变对粗旋上下行气量分配有一定影响,其长度选取均存在最佳范围;尺寸放大后,粗旋流场基本上相似,下行气量占进气量的比率略有增大。     

FC-28型单段高中油型加氢裂化催化剂的工业放大

以改性Y型分子筛为主要酸性组分，钨镍为加氢组分，采用浸渍法制备了FC-28型单段高中油型加氢裂化催化剂。FC-28型单段高中油型加氢裂化催化剂工业放大结果表明，该催化剂制备工艺成熟可靠，重复性好，FC-28型放大催化剂的反应性能完全达到了实验室定型催化剂的水平。FC-28型单段高中油型加氢裂化催化剂工艺条件考察试验结果表明，该催化剂对工艺条件变化适应性强，中间馏分油产率高，活性适中，并具有较好稳定性。     

Experimental simulation of large-scale bioreaetor environments using a Monte Carlo method

Cells grown in production-scale stirred bioreactors experience fluctuating concentrations due to local variations in supply and consumption of oxygen and nutrients. A new method for studying the effects of fluctuations in local conditions on growth and productivity of cells was developed using a Monte Carlo approach to simulate circulation within a fermenter. A small fermenter was driven through cycles of aeration and feeding, with the time of each cycle controlled by a Monte Carlo method to give a log-normal distribution. Experiments with Monte Carlo supply of air to batch and fed-batch cultures of Saccharomyces cerevisiae showed that the method gave reproducible results which were different from both periodic cycling and continuous supply. When substrate was provided to a fed-batch culture of S. cerevisiae according to the Monte Carlo method, the yields of biomass were higher than experiments with continuous feeding or periodic feeding.