Simulation of packed-bed separation processes using orthogonal collocation

The two-point boundary value problem resulting from the heat and material balance equations of a packed separation column are solved using polynomial approximation techniques. The model equations are based on the two-film theory of mass transfer. The resulting partial differential equations are first reduced to ordinary differential equations and then integrated using semi-implicit Runge-Kutta method of integration. Application of orthogonal collocation simplifies the solution of the two-point boundary value problem. For the examples studied, the algorithm is found to converge rapidly with respect to the number of collocation points used in the polynomial approximation.     

基于事例推理的主生产计划系统

为了快速、准确地获得最佳的主生产计划 ,在分析主生产计划系统中关键问题的基础上 ,探讨了基于事例推理技术在资源需求求解中的运用 ,提出了基于事例推理的主生产计划系统基本结构。基于事例推理技术的应用 ,加速了资源需求剖面的形成和求解的正确性 ,从而提高了主生产计划系统的效率和可靠性     

面向铁钢对应的两级案例推理铁水动态调度系统

针对铁水动态调度的多扰动、实时性强等特点,以及铁钢对应对于铁水在时间、质量、成分、温度等指标上的要求,提出了基于两级案例推理的铁水动态调度系统体系结构。根据生产现场各种扰动的特点,对两级案例库进行了案例分类。研究了铁水动态调度系统的两级案例表示方法、案例检索与匹配、案例的调整及维护等关键技术,最后给出了两级案例动态调度结果满意度的综合评价指标。采用大量的生产现场数据对系统进行了测试验证,测试结果表明系统推理速度较快,稳定性较高,动态调度结果合理有效,两级案例推理的技术方法具有广泛的应用前景。     

Synthesis of augmented biofuel processes using solar energy

A method for synthesizing augmented biofuel processes, which improve biomass carbon conversion to liquid fuel (η_carbon) using supplemental solar energy as heat, H₂, and electricity is presented. For a target η_carbon, our method identifies augmented processes requiring the least solar energy input. A nonconvex mixed integer nonlinear programming model allowing for simultaneous mass, heat, and power integration, is built over a process superstructure and solved using global optimization tools. As a case study, biomass thermochemical conversion via gasification/Fischer–Tropsch synthesis and fast‐hydropyrolysis/hydrodeoxygenation (HDO) is considered. The optimal process configurations can be categorized either as standalone (η_carbon ≤ 54%), augmented using solar heat (54% ≤ η_carbon ≤ 74%), or augmented using solar heat and H₂ (74 ≤ η_carbon ≤ 95%). Importantly, the process H₂ consumption is found to be close to the derived theoretical minimum values. To accommodate for the intermittency of solar heat/H₂, we suggest processes that can operate at low and high η_carbon. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2533–2545, 2014     

Automated affinity separation processes

This paper describes the automation of fixed-bed affinity separation techniques for the purification of proteins. The basic requirements of an automated system suitable for carrying out such a separation are detailed together with an introduction to the concept of process optimisation by interactive control. Such systems can continue to optimise separations when operating conditions are variable but require that methods for the on-line analysis of separation performance are available. Such methods require that the levels of particular proteins in the presence of other proteins can be determined and include continuous measurement of enzyme activity and the use of the new technique of rapid chromatographic analysis. The latter technique, which can also be used more generally in the process control of protein purification, is described and its use illustrated.     

Calculation of multistage countercurrent separation processes—II multicomponent multistage separation by relaxation procedure

The relaxation method used for solution of problems arising in design of multicomponent separation processes is discussed and new modifications are proposed. The use of certain techniques for convergence acceleration is studied. The number of iterations is then substantially reduced and effectiveness of relaxation method is thus highly improved.This method is useful also for columns with multiple feeds, intercoolers etc., however, nonideal mixture can be conveniently handled. A modification of the relaxation procedure resulting in a pentadiagonal matrix is presented.     

基于数据融合与案例推理的球磨机负荷优化控制

在以球磨机为主要生产设备的工业过程中,球磨机负荷是与生产效率和能源消耗密切相关的重要指标。针对难以采用常规方法控制球磨机负荷的难题,将多传感器数据融合和案例推理方法相结合,提出了氧化铝生料浆配料过程的球磨机负荷优化控制方法。利用球磨机的振动和电流信号,采用多传感器数据融合方法在线估计出球磨机的负荷状态,在此基础上,采用案例推理方法自动调整进入球磨机的干料总量,从而使球磨机在“最佳负荷状态”下运行。将所提出的优化控制方法进行工业实验,结果表明,球磨机的台时产能得到了较大提高,同时降低了能源消耗并减少了“堵磨”故障次数,取得了良好的经济效益。所提出的方法为化工、冶金和电力等其他行业的球磨机负荷控制提供了重要的参考价值。     

Complementary modelling of fluid separation processes

Optimal functioning of numerous technological processes depends primarily on relevant process design, properly selected column internals and sufficient understanding of the process behaviour. This can be achieved only with the help of accurate and reliable process models capable of considering process rates in a rigorous way, with respect to both transport phenomena and chemistry. In this article, a new modelling concept called complementary modelling is suggested for a large class of fluid separation processes. Since the conditions and criteria for these processes vary considerably, it is impossible to develop a unified modelling approach. Instead, a reasonable and effective combination of different modelling approaches provides solutions to many present and future tasks. The complementary modelling is discussed in detail and illustrated with several case studies.     

Multi-objective optimisation of batch separation processes

This paper considers for the first time the simultaneous multi-objective optimisation of design and operation of batch distillation as well as of batch hybrid distillation/pervaporation processes. The overall problem is formulated as a multi-objective mixed integer dynamic optimisation (MO-MIDO) problem. The optimisation strategy comprises of different ranking procedures that allow the determination of the Pareto optimal set. A case study for the separation of a homogeneous tangent-pinch (acetone–water) mixture is presented for a dual-criteria optimisation case of minimising capital investment while at the same time minimising the energy consumption rate during the batch. It is found that the proposed distance ranking procedure yields the best Pareto optimal set when compared to other non-dominated sorting procedures. Furthermore, the distance ranking procedure was found to be further improved when used with an elitism operator.     

基于模糊粗糙集和事例推理的凝汽器真空故障诊断

针对凝汽器真空故障诊断的不确定性和复杂性,提出一种基于模糊粗糙集和事例推理的凝汽器故障诊断新方法。首先,运用模糊粗糙集属性约简方法对故障特征进行约简和权重分配,不仅提取了反映故障的主要特征量,降低了特征变量之间的非线性相关性,而且避免了人的主观性对权重分配的影响。然后,在分析凝汽器真空故障特征的基础上,建立凝汽器真空故障树,以约简特征作为条件对故障树根节点进行归纳检索,有效地减少了候选事例的数量,再通过最近邻法检索故障树叶节点,对凝汽器真空故障进行智能定位。通过对汽轮机凝汽器历史故障特征数据集仿真,验证了该方法的有效性。     

Imprinted membranes for sustainable separation processes

The rapid industrial growth and the necessity of recovering and recycling raw materials increased the interest in the production of highly selective and efficient separation tools. In this perspective, a relevant input was given by the membrane-based technology and the production of imprinted membranes, which possess specific recognition properties at molecular and ionic level, offers the possibility of developing sustainable and green processes. Furthermore, the integration of imprinted membranes with traditional or membrane-based approaches is a promising strategy in the logic of process intensification, which means the combination of different operations in a single apparatus. This work discusses the concept and separation mechanisms of imprinted membranes. Furthermore, it presents an overview of their application in organic solvent nanofiltration, for the removal of toxic agents and recovery solvent, as well as valuable compounds. The recent advances in water treatment, such as pesticide removal and recovery of metal ions, are also discussed. Finally, potential applications of imprinted membranes in hybrid processes are highlighted, and a look into the future of membrane separations for water treatment and recovery of critical raw materials is offered.     

Dual-layer hollow fibers for gas separation processes produced by quadruple spinning

A novel quadruple spinneret to produce dual-layer hollow fiber membranes by simultaneous spinning of two polymer solutions, using the dual precipitation bath technique is proposed. Hollow fibers aimed at gas separation processes were prepared in extrusion system specifically designed and built for this purpose. A polyurethane polymer was selected as the selective layer (outer-layer), while polyethersulfone was defined as the support (inner-layer). Activated carbon powder was added into the PU solution for further improvement of the transport properties. The hollow fibers showed good adhesion between the polymer layers and a defect-free selective layer. Representative results include a CO₂/N₂ selectivity of 43.     

Design and analysis of nonequilibrium separation processes

Design and analysis of nonequilibrium separation process problem are discussed. Even though there have been published articles on the design and analysis of equilibrium separation process problems, these issues have not been addressed in great detail as far as nonequilibrium problems are concerned. Strategies are developed for drawing residue curve maps using mass-transfer model equations. In addition the multistage nonequilibrium separation process problem is rigorously analyzed and it is shown that, as in the single-stage case, any multiplicity that occurs is a result of the multiplicity that occurs here in the phase equilibrium calculations at the interface.     

Separation characteristics of pervaporation membrane separation processes using modified poly(vinyl alcohol) membranes

Modified poly(vinyl alcohol) (PVA) membranes prepared by the ‘solution technique’ were tested for ethanol-water mixtures by varying the reaction density (X_cr = 0.05, 0.1) at various temperatures. The results are compared with those of PVA membranes (X_cr = 0.05) prepared by the technique of the GFT Company, Germany.     

溴代咔唑的合成及正相高效液相色谱分离

用直接溴化法合成了４种不同取代的溴代咔唑。首次用正相高效液相色谱对它们的纯度进行了检验,并分离了这一系列化合物。     

对氯甲苯的合成与分离工艺评述

介绍了国内外对氯甲苯的合成与分离工艺。     

Oil-water separation using hydrocyclones enhanced by air bubbles

In order to improve the separation efficiency of dispersed oil from water by hydrocyclones, a new process of utilizing air bubbles has been developed to enhance the separation efficiency. The air bubbles attach themselves to the oil droplets and cause a decrease in the overall density of the phase, the difficulty of agglomerating can thus be circumvented. The air-liquid ratio of 1% was found to provide the best separation. When the inlet Reynolds number ranges from 14,000 to 16,000, the oil removal efficiency increases from 72% (air-liquid ratio 0%) to 85% (air-liquid ratio 1%). The process has been found to be very efficient in the separation of suspended oil from water.