金属溶剂萃取三出口工艺的数学模拟研究

本文对于总分配比恒定的串级萃取三出口工艺数学模拟,提出了一种较为简单实用的方法,对皂化 P507—煤油体系分离 Cu、Co、Ni 三种元素的三出口工艺用矩阵法进行了串级模拟计算,与实验对比较好地反映了串级分离过程中各元素的分布规律。     

稀土串级萃取分离过程的双线性模型及其参数辨识

稀土串级萃取分离过程元素组分含量的在线检测对于提高金属直收率至关重要,由于难以实现连续在线测量,因此研究动态模型成为采用软测量技术的关键．本文以稀土串级萃取分离过程的物料平衡方程为基础,提出了一种具有状态滞后的双线性动态模型,并对模型进行了分段集结降阶简化．通过工业现场采集的数据,采用最小二乘法对模型参数进行辨识,并根据误差指标选择最佳系统时滞,得到了表征稀土串级萃取分离过程的动态数学模型．稀土串级萃取分离过程实际数据的仿真结果表明了该建模方法的有效性和模型的准确性．     

Elman网络对铈镨/钕萃取过程的应用研究

鉴于稀土元素铈镨/钕(CePr/Nd)的萃取是一个非线性、强耦合的复杂过程,难以建立精准的过程模型.利用实际萃取过程的萃取剂流量和洗涤剂流量作为输入,监测级两端组分含量作为输出.然后根据稀土元素CePr/Nd萃取生产过程的工艺参数要求,利用串级萃取理论对CePr/Nd元素的萃取过程进行模拟,分析每个串级的CePr/Nd含量的分布.再结合实际生产过程中采集的数据,建立稀土CePr/Nd萃取过程模拟的Elman网络模型,从而确保两端出口产品最终达到所需纯度.最后通过稀土萃取过程BP、RBF、Elman建模策略进行了仿真对比,结果表明:萃取过程Elman模型具有更高的预测精度和更好的稳定性,可为稀土萃取生产过程工艺参数调整提供可靠的信息依据.     

钴,镍萃取平衡数学模型及串级萃取过程最优化计算

本文把ＣｏＣｌ２－ＮｉＣｌ２－Ｈ２Ｏ－Ｒ３Ｒ’ＮＣｌ萃取平衡体系的实验数据关联为数学模型，对萃取过程进行串级模拟和最优化计算，并在日处理０．９Ｍ＾３料液的生产性试验中得到验证。计算得到的主要工艺参数，两相出口的主要指标，各组分浓度及分配比的逐级分布都与试验结果基本相符。     

浅析加热炉的几种主要控制方案

本文介绍了加热炉出口温度单回流控制、串级控制、前馈-反馈控制、前馈-反馈串级控制、入口多路流量均匀控制、燃烧系统的交叉限幅控制等几种主要控制方案以及加热炉的常规联锁,并对其进行了分析。     

串级参数自适应计算机控制系统的动态综合

采用串级控制可简化主回路的过程模型及相应的控制算法。本文论述了串级数字控制系统的特点和常参数串级控制系统的动态综合以及应用参数辨识技术及自动补偿措施实现参数自适应控制的方法。     

丙酮和正己烷共沸体系萃取精馏的模拟优化

利用化工流程模拟软件Aspen Plus以NMP为萃取剂对丙酮和正己烷共沸物系的双塔连续萃取精馏过程进行了模拟计算与优化。确定最优工艺方案为:萃取精馏塔理论板数32,正己烷与丙酮原料进料位置为第25块理论板,萃取剂进料位置为第4块理论板数,溶剂比1.8,回流比1;溶剂回收塔理论板数为7块,回流比为0.6,进料位置为第4块理论板数。萃取精馏塔塔顶产品正己烷含量达到99.84%,萃取剂回收塔塔顶丙酮含量达到99.88%。模拟和优化结果为分离过程的优化操作和设计提供理论依据。     

三聚甲醛萃取—精馏新工艺及过程优化

本文对采用Ｓ１和Ｓ２的混合物作为萃取剂的三聚甲醛萃取－精馏新工艺进行了模拟计算，得到了使总费用最低的三聚甲醛精制工艺的联合操作参数。模拟计算结果成功地指导了小试操作，并可为大型工程设计提供可靠的基础数据。     

萃取精馏法从加氢裂解C9芳烃中脱除茚满的模拟与优化（英文）

选择丙三醇为萃取剂,采用ASPEN PLUS化工流程模拟软件对萃取精馏法从加氢裂解C9芳烃中脱除茚满的过程进行模拟计算。考察了理论塔板数、进料位置、萃取剂进料位置、溶剂比及回流比等操作参数对萃取精馏分离效果的影响,并通过正交试验对各操作参数进一步优化。结果表明:当理论塔板数为45、进料位置在第24-26块塔板、萃取剂进料位置为第5块塔板、溶剂比为2.0、回流比为1时,萃取精馏塔顶馏出液中茚满的含量可控制在1%以下。     

带有热量集成的乙醇-水萃取精馏过程模拟

使用Aspen Plus,首先对乙醇-水萃取精馏过程的7种萃取剂的分离效能进行了模拟比较,结果显示:丙三醇DMSO乙二醇DMF糠醛苯甲醛NMP;接着,以丙三醇为萃取剂,设计了最优的萃取精馏工艺流程,并确定了萃取精馏过程中萃取精馏塔(理论板数:16,回流比:2,原料进料位置:12,萃取剂的进料量:230 kmol/hr和进料位置:4)和溶剂回收塔(理论板数:7,进料位置:3和回流比:3)的最佳工艺条件;最后,本文还利用热量集成的方法对系统的废热进行了回收利用,不但节约能耗3262.72 kW,还顺产1 MPa低压蒸汽127 kmol/hr。本研究为乙醇.水萃取精馏分离工艺的工业化提供了理论依据和设计参数。     

芳烃联合装置邻二甲苯精馏塔流程模拟与优化

化工流程模拟软件不断发展,越来越多的化工装置开始采用流程模拟来优化装置的操作。基于精馏过程的实际运行数据,建立了能够良好描述装置实际运行工况的模型,实现了对芳烃联合装置邻二甲苯精馏过程的流程模拟。利用Aspen Plus建立装置模型,按照工艺条件及产品分离要求,使用设计规定工具,对采用精馏方式从混合C8～C10物料中分离邻二甲苯(OX)工艺进行研究。模拟结果与实际工业过程数据相符,能够满足工业建模的要求。基于模型,研究了进料塔板位置、回流比和塔顶采出量等变量对装置稳定运行的影响,从进料塔板,塔顶采出量和进料组分等方面提出了优化建议。研究结果表明:精馏塔塔顶采出量为OX产品主要杂质异丙苯(IPB)含量的显著影响因素。据此提出了包括回流比和塔顶采出量参数的优化方案,可以使主要杂质异丙苯的含量下降40%的同时,每年可节省燃料成本。     

内存泄漏的动态跟踪分析

内存泄漏是软件开发中的一个难以定位和修正的严重错误。在大多数情况下,动态内存的有效域虽未明确写出,但仍是程序的局部;且程序动态运行的轨迹在一定程度上反映程序的静态性质。基于以上观察,开发了在面向函数定位框架中嵌入动态分析的内存泄漏监测新方法。新方法中,先建立程序的函数动态调用树,其中包含程序分配释放内存的信息,再在调用树中总结程序的静态性质,为内存泄漏定位提供有价值的信息。该文用两个实例展示这个方法的有效性。     

On the conditional superiority of counter-current over co-current extraction in microchannels

In liquid–liquid extraction, counter-current flow of the phases always results in an improved performance as compared to co-current flow, under similar operating conditions. However, it is challenging to implement counter-current flow in a microchannel. Therefore, the improvement in extraction performance must be significant to justify the selection of counter-current flow over co-current flow in microchannels. In this study, we identify the range of fluid properties and operating conditions for which counter-current operation exhibits significant benefits. For this, simplified mathematical models are developed for both co-current and counter-current extraction in the stratified flow regime. These models, while being simple, capture the essential physics of the extraction process and facilitate a thorough investigation of the relative extraction performance across the parameter space. An analytical solution, based on the theory of Sturm–Liouville linear operators, is obtained for the case of co-current flow. The counter-current model belongs to the class of two-way diffusion equations for which a novel semi-analytical solution is presented. The analysis of the predictions of the models shows that the relative extraction performance is governed by a general principle of maximum gain at mediocre performance. These results help identify the significantly restricted range of operating parameters for which counter-current operation is a truly attractive alternative to the co-current mode of extraction in microchannels.     

Integrated fabrication of electrostatic microactuator for HDD R/W head positioning

We designed an electrostatic actuator which can work with the voice coil motor in a dual-stage servo control system to accurately position the read/write (R/W) head in hard disk drives. An integrated fabrication process for this microactuator has been proposed, considering total fabrication of R/W head and alumina-titanium carbide (AlTiC) slider. Adhesive bonding technique using photoresist SU-8 was selected for wafer bonding between silicon and AlTiC. A microactuator prototype has been fabricated by the proposed process. The stroke of the microactuator has been measured during the static testing.     

Modeling and simulation of a SMB chromatographic process designed for enantioseparation

This paper focuses on modeling of a simulated moving bed process (SMB) dedicated to the separation of racemic mixtures. In the first approach, a true moving bed model is derived, which assumes an equivalent counter-current movement of the solid phase. The good agreement between the model and the real system is demonstrated with experimental results. Then, a more rigorous approach is developed, which considers the system as an arrangement of static chromatographic columns and takes into account periodic switching. Attention is focused on model formulation and numerical solution techniques in order to develop efficient dynamic simulation programs.     

激光切割图形显示和校验研究

研究了激光切割图形显示和校验方法。编程人员通过图形显示，将所编辑的NC代码映射为直观的图形，并与用户要求的零件轮廓比较，从而纠正编程错误及工艺不合理，通过图形校验功能可以自动求出零件轮廓是否经过了顶针保护区，在避开顶外保护区的情况下，可以在编程人员的授权下自动修改NC代码，全部软件用C语言开发，已成功地用于激光切割系统中。     

基于Smith预估模糊PID控制的加热器温控系统

针对工业加热器出口温度具有大滞后、大时变、非线性以及精确模型难以建立等特性导致的工况复杂、控制难度大的问题,提出一种Smith预估模糊PID复合控制方案,利用模糊控制规则实现PID的3个参数在线自整定,采用Smith预估器对温控系统的纯滞后进行补偿。详细阐述温控系统的硬件配置和软件实现,实际运行结果表明该方案有效提高了系统的抗干扰能力和适应参数变化的能力,具有鲁棒性强、动态响应快及稳态精度高的优点。     

C++程序中异常处理的分析与测试技术研究

异常处理机制是一种运行时错误通知机制，将程序的正常控制代码和错误处理代码分离．然而异常机制的引入使得程序控制信息变得更为复杂；且开发人员一般难以熟练使用它，导致程序中会潜伏许多异常错误．扩展已有的显式异常分析技术，对隐式异常也进行了全面的分析并提出了过程间（内）控制流图的构造方法，并以此为基础给出了一个C＋＋程序健壮性改进模型．同时还提出了针对异常的两种动态测试策略：基于约束求解的异常测试策略和统计结构性异常测试策略．最后实现了一个初步的异常分析与测试原型工具并进行了初步实验分析，其结果表明本文提出的分析与测试方法对程序质量有较大程度的提高．     

CFD analysis of performance characteristics of S-shaped diffusers with combined horizontal and vertical offsets

This paper presents the effect of combined horizontal (90°/90° turn) and vertical offsets (inlet and outlet in two different horizontal planes) on S-shaped diffusers, one with rectangular inlet (AS = 2) and rectangular outlet and other with rectangular inlet (AS = 2) and semi-circular outlet with area ratio 2 in both the cases having downstream settling length of 50 mm at Reynolds number 1.37 × 10⁵. A computer program based on finite volume technique, using standard k–ε turbulence model, has been adopted and modified to predict the flow. The results obtained from this study indicate reduced outlet pressure recovery accompanied with increase in non-uniformity in flow at the exit contributed by the offset effect. The comparison of pressure recovery of the extreme vertical offset value i.e. 1B in case of rectangular outlet diffuser and 1D in case of semi-circular outlet diffuser with zero vertical offset indicates that there is significant drop of pressure of the order of 14% and 7.3% respectively. Non-uniformity in flow at the outlet also increases from 12% to 32% and 6.4% to 21% in case of S-shaped diffuser with rectangular outlet and S-shaped diffuser with semi-circular outlet respectively, starting from zero vertical offset to extreme vertical offsetting magnitude for the case. This paper also shows that increase in Reynolds number has marginal effect on the outlet pressure recovery for both types of diffuser with all cases of vertical offset. The S-diffuser with semi-circular outlet with 0.25D vertical offsetting only fulfills most of the requirements of the flow diffusion process efficiently and effectively. For other cases, redesigning of geometry is required.