Scale-up of a cyclone bioreactor

The operation of a cyclone bioreactor differs from conventional stirred tanks since the agitation is accomplished by means of a pumped reciculation loop. Oxygen transfer can occur across the swirling gas—liquid interface in the cyclone or from bubbles entrained in the recirculation loop. A cyclone bioreactor was scaled-up from a 1 dm³ bench top unit to a 75 dm³ Process Development Unit (PDU). A reduction in the aspect ratio was compensated for by extending the length of the recirculation loop and providing additional aeration. Performance of the two reactors for the production of microbial poly-β-hydroxybutyrate (PHB) was compared under various operation conditions. The culture used for PHB production was Alcaligenes eutrophus DSM 545, grown on a mineral salts medium limited by the supply of nitrogen. The levels of dissolved oxygen obtained in the PDU were strongly dependent on the location at which the air was introduced into the reactor. However, with aeration balanced between two injection points and a similar level of power input, 17 J s^?1 dm^?3, the PDU was able to provide at least as much oxygen transfer capability as the laboratory-scale reactor. Under all conditions tested, the PHB accumulation by A. eutrophus was in excess of 80% of the biomass dry weight, although the yield on glucose was lower in the PDU than in the laboratory-scale reactor.     

Some aspects of electrochemical engineering

After a short discussion of the concept of electrochemical engineering, the immediate history of electrochemical process engineering (EPE) is briefly mentioned. Topics then considered are electrolytic reactor design, process modelling and optimisation, and the development and scale-up of electroorganic processes. The article concludes with an assessment of the present state of EPE.     

液体搅拌的放大

介绍了几种常用的液体搅拌放大的判据,并对流量型搅拌、气液分散、液液分散、固液悬浮以及结晶过程的搅拌,分别提出了适用的放大判据。对于几何学条件,有的可以是几何相似的,有的则不能采用几何相似。还讨论了以单位容积功率作为放大判据时,可能出现的问题和改进措施。     

气-液-固滴流床反应器放大中的重要参数及其数学模型

介绍了在滴流床反应器放大过程中所涉及到的物理化学参数和数学模型建立的方法，并对这些参数计算的经验公式进行了综述，为滴流床反应器的模拟、放大提供了理论依据。     

毛细管基微流体放大系统流体流量分配的研究

微流体在平行通道中的均匀分配是实现微流体控制放量制备粒径单分散性功能微球的重要技术。本研究设计了毛细管基微流体控制放大装置,详细研究了毛细管尺寸、毛细管长度、流体流量以及流体粘度对微流体流量均分的影响。研究结果表明,随着毛细管内径的减小、毛细管长度的增加、流体流量的增大、流体粘度的增加,流体流量分配均匀性更好,即流体流量变异系数(CV)变小。研究获得了描述CV与其影响参数之间关系的经验公式。     

Extruder scale-up assessment in the process of extrusion–spheronization: comparison of radial and axial systems by a design of experiments approach

Scaling-up the extrusion–spheronization process involves the separate scale-up of each of the five process steps: dry mixing, granulation, extrusion, spheronization, and drying. The aim of the study was to compare two screw extrusion systems regarding their suitability for scaling-up. Two drug substances of high- and low-solubility in water were retained at different concentrations as formulation variables. Different spheronization times were tested. The productivity of the process was followed up using the extrusion rate and yield. Pellets were characterized by their size and shape, and by their structural and mechanical properties. A response surface design of experiments was built to evaluate the influence of the different variables and their interactions on each response, and to select the type of extrusion which provides the best results in terms of product quality, the one which shows less influence on the product after scale-up (“scalability”) and when the formula used changes (“robustness”), and the one which allows the possibility to adjust pellet properties with spheronization variables (“flexibility”). Axial system showed the best characteristics in terms of product quality at lab and industrial scales, the best robustness at industrial scale, and the best scalability, by comparison with radial system. Axial system thus appeared as the easiest scaled-up system. Compared to lab scale, the conclusions observed at industrial scale were the same in terms of product quality, but different for robustness and flexibility, which confirmed the importance to test the systems at industrial scale before acquiring the equipment.     

Scaling up an Emulsions Production System of Heavy Oil Liquid Residuals in Water

Abstract

The aim of the present study is the investigation of the scaling-up procedures to emulsify heavy oil liquid residuals in water from a continuous emulsion production system at laboratory scale to a semi-pilot plant emulsion production system. The results obtained for the particle size distribution are compared in each case. The experiments were performed using the same liquid residual flow, temperature process, and volume fraction of the dispersed phase at atmospheric pressure. The particle size distribution was measured by a Mastersizer Micro Optical Bench Model MAF5000 from Malvern Instruments. Satisfactory results of the scaled system are presented, and some considerations—mainly in the operational parameters for future studies—are also described.     

On the scaling-up of a two-stage air blown entrained flow coal gasifier

A two-stage air blown entrained flow gasifier is being developed in Japan for the IGCC process. However, its scale-up up faces significant difficulties because of ash/slag deposition problems. The ash/slag deposition in the gasifier depends on both the ash properties and entrainment produced by the swirling gas flow. Therefore, the flow hydrodynamics are critical issues for the control of the ash behavior. In this paper, a comprehensive simulation model is used to examine the effects of the gasifier geometry and jet configuration on the flow hydrodynamics in order to control the ash deposition on the gasifier walls. A swirl number for the multi-stage injection swirling gas flow is defined and proved to be the most important hydrodynamic scaling law for the entrained flow gasifier.