Packed-microtubes model for flowthrough chromatography of protein

A mathematical model for flowthrough (perfusion) chromatography, namely packed-microtubes (PMT) model, has been proposed for a column packed with biporous (BiP) anion exchanger in which the mesopores and flowthrough pores are created with liquid and solid porogens, respectively. The model is established based on the assumption that the BiP particle is made up of packed microtubes. Bovine serum albumin (BSA) is used as a model protein and three kinds of anion exchangers (i.e., mesoporous, macroporous and BiP resins) are used as adsorbents to determine the model parameters and to evaluate the model. Adsorption equilibrium and finite bath experiments are performed to determine the adsorption isotherms and kinetics parameters. Both the bound amounts of the protein on the surface of the mesopores and macropores are experimentally determined and taken into account in the mathematical model. With all the model parameters determined by independent experiments or calculated from available correlations, model simulations are performed and compared with the experimentally determined breakthrough profiles of the BiP column. It is found that the model predictions agree reasonably well with the experimental data obtained under various conditions and the PMT model fit experimental data better than the modified double linear driving force (LLDF) model proposed by Leitão and Rodriogues (1999. Biochemical Engineering Journal 3, 131) in which the adsorbent particle is considered to be made up of packed microparticles. The results indicate that the PMT model is more reasonable for this kind of BiP adsorbent.     

Reply to the Comment by K. Jorgensen et al. to “Analysis of constant rate period of spray drying of slurry”

Previously developed model for spray drying of slurry droplets with high solid content (Liang, 2001) was revised to describe correctly a boundary condition on the outer surface of droplet on basis of the rate of liquid evaporation.     

提高炼厂气综合利用水平的途径

公司将进行催化裂化装置、气体分馏装置改造。预计改造后的丙烯产量将达到5．0万t／a，丁烯等C4产品大大增加。聚丙烯是公司目前丙烯化工利用的唯一产品，年产量2万t，C4的化工利用尚属空白。因此开辟过剩丙烯利用新途径，带动C4产业发展，形成化工产业链，提高公司炼厂气的综合利用水平，具有重要意义。合成异丙醇或环氧丙烷，就是这样一个突破口。     

四丁基脲的合成方法

四丁基脲(简称TBU)是一种用途很广的有机合成中间体,对其制备方法的研究具有重要的现实意义。笔者系统介绍了合成四丁基脲的方法,归纳分析目前生产四丁基脲的方法,比较各种方法的优缺点,并对今后的研究方向进行了展望。     

乙酸乙酯反应精馏生产工艺模拟研究

以实际生产数据为基础，运用化工稳态模拟计算软件ASPEN PLUS，在建立现有乙酸乙酯酯化工艺仿真模型的基础上，对现有工艺进行改进，采用催化剂循环的方式，建立了生产乙酸乙酯的反应精馏新体系的计算机仿真模型。模拟研究结果表明：乙酸乙酯的带循环反应精馏新工艺是可行的，在相同的进料条件、相同的设备规格下，相比于现有生产工艺，新工艺提高生产能力约24％，同时降低了能耗和节省了设备投资。     

PET短纤维后纺上油衡算方程及上油形式的评价

建立了合成纤维湿热和高温上油模型及其衡算方程。该方程可用于设计参考和指导工业生产。评价了合成纤维常规上油形式的技术性和经济性,指出选择合理的上油形式,可降低油剂消耗,提高装置的经济效益。     

基于回归模型的CPU超频仿真软件设计

为了帮助认识CPU超频问题并熟悉超频设置操作,进行CPU超频仿真软件设计的全面研究。分析CPU超频的影响因素,介绍超频的方法和操作流程;讨论软件的功能模块结构、模块的运行流程和样本数据的存储方法;重点研究CPU超频后的性能测试结果估计问题,并为此提出了建立回归模型的解决之道;详细探讨了VB.NET与Matlab混合编程的接口与实现途径,并以此种方式完成了程序代码的编写。试用表明,该软件功能完整、界面直观、使用简便,能够为理解超频理论和熟悉超频操作提供有效帮助。     

Simulation of reactive precipitation processes using the network-of-zones model

A 2-D network-of-zones model is extended and applied to a reactive precipitation process in batch mode. The simulations are performed for a network of size 2 × (10 × 10) for an elementary reaction through the solution of 1400 ODEs. The complicated interactions between mixing efficacy and the system kinetics are systematically investigated. When the stirrer speed is very slow, the crystal size distribution (CSD) of the product in the precipitator is determined by the intensity of mixing. Conversely, at higher stirrer speed, the CSD is controlled by the system kinetics. More effective mixing leads to an increase in the number of crystals, a reduction of the average size and a narrower crystal size distribution. The extended network-of-zones model presented in this work can be used conveniently for integrating computational fluid dynamics and reactive precipitation processes.     

推行清洁生产的战略意义及途径

介绍了清洁生产的内容,分析了推行清洁生产的意义,并对我国实施清洁生产的途径进行了讨论.