工业结晶技术前沿

综述了近２０年来国内外工业结晶发展概况，特别介绍了有关熔融结晶、溶液结晶及反应沉淀结晶的技术发展，并针对我国工业结晶领域现状提出了几点建议与对策     

熔融结晶过程的新进展

本文综述了工业结晶过程的一个主要部分,即熔融结晶过程的新进展。重点介绍了国内外各种新型塔式熔融结晶装置的研究、开发与工业应用的现况;并比较了它们的优缺点。本文对已提出两种基本传递过程的数学模型也做了简单的阐述。     

连续管式结晶器研究进展

结晶是大多数化工生产过程中必不可缺的步骤。目前,大部分结晶过程采用间歇结晶,但间歇结晶的生产模式存在批次间差异、生产成本过高等缺点。因此,连续结晶作为新的结晶模式逐渐成为研究的重点。其中,连续管式结晶器具有较窄的停留时间分布和较高的生产效率等优势,已广泛应用于工业结晶。针对连续管式结晶器研究现状进行了详细介绍,总结了管式结晶器普遍存在的问题和解决方法,并介绍了辅助设备和技术在连续管式结晶器中的应用。最后,总结了管式结晶器的进一步发展方向。     

单质炸药结晶控制技术研究进展

根据结晶学原理,对结晶过程中影响结晶质量的因素进行了讨论,论述了国内外单质炸药结晶控制技术的概况,并对单质炸药结晶控制技术和结晶方法进行了分析和比较。预测了在线颗粒分析系统(FBRM)应用于单质炸药结晶控制中的价值。认为直接从反应液中制得满足使用要求的结晶产品具有较好的工业前景。     

L-缬氨酸结晶工艺研究进展

简述了L-缬氨酸的发展现状、生产工艺、含量测定方法,分析了工业结晶过程中工艺条件对L-缬氨酸产品质量的影响,展望了国产L-缬氨酸工业提升产品质量的发展方向,指出深入开展L-缬氨酸工业结晶过程研究,开发具有自主知识产权的国产L-缬氨酸新工艺,对于提升国产L-缬氨酸产品质量和增加国内生产企业的国际竞争力具有重要意义。     

DMT装置真空结晶工艺剖析

运用结晶机理，对ＤＭＴ结晶工艺条件进行了优化选择，并结合改造实践，对真空结晶工艺进行分析、总结，为工业结晶提高生产能力、节能、降耗、高效运行提供了新的途径。     

间歇结晶过程最佳操作时间表安排的研究

本研究对间歇冷却结晶过程的数学模型进行了分析,根据动态法测定得到的结晶成核速率B与成长速率G相关于降温速率U的函数关系的经验式,推导出描述过程的状态方程组,协状态方程组及Hamitonian函数,应用Pontryagin极大值原理对过程进行了最优控制条件的计算,建立了一个求解间歇冷却结晶最佳操作时间表安排的新型应用软件.并在DTB型工业规模的结晶器中进行了冷却间歇结晶实验.软件计算结果与实验结果的一致性,充分验证了软件的适用性.本研究所建立的简捷法策略与应用软件可用于指导Ⅱ类结晶物系间歇冷却结晶过程的操作与设计.     

结晶技术的研究进展及应用

简要概述了目前工业结晶的技术现状,阐述了蒸馏-结晶耦合技术、离解萃取结晶技术、诱导沉淀结晶技术、膜蒸馏-结晶技术、鼓泡结晶技术及超临界流体结晶技术的原理与应用现状。提出了不同结晶技术目前存在的主要问题并对其研究动向进行了展望。     

高纯度苯甲酸精制工艺述评

介绍了结晶法精制苯甲酸的三种工艺－升华结晶，溶液结晶，熔融结晶。重点评述了熔融结晶法的装置与应用现状，同时展望了苯甲酸精制的未来发展动向。     

工业结晶过程中结晶动力学模型探讨

针对工业结晶过程中的溶液结晶部分,探讨了晶体成核和成长的动力学模型,并对模型的应用情况进行了简单的阐述。     

Untersuchungen zum Kristallisationsfouling in Mikrowärmeübertragern

The advantages of microstructure devices concerning heat and mass transfer are well known. However, the usage of microstructure devices in chemical industry is still limited today. A limitation for industrial application is the liability of microstructures to blocking due to impurity of the fluid or by unintended deposition (fouling) in the microchannels. Fouling can lead to a degradation of the heat transfer performance, to an increase of the pressure drop, to a change of the fluid distribution in the microstructures and to a shorter residence time of the fluid. In the framework of this research project a micro heat exchanger for fundamental experimental investigations on crystallization fouling of CaCO₃ in microchannels was developed and manufactured.     

溶剂结晶法分离精制豆甾醇工艺对比

通过对溶剂结晶法分离精制豆甾醇工艺进行对比分析,得出工艺简单、适合工业化生产工艺路线。介绍国内外溶剂结晶法（多级分步结晶法、极性溶剂结晶法、有机溶剂结晶法）分离精制豆甾醇的工艺方法并进行对比,可知有机溶剂结晶法中的重结晶法工艺比较简单,非常适合工业化生产。     

Structure‐property relationships in commercial polyetheretherketone resins

Key relationships between molecular structure and final properties are reported for standard flow and high flow grades of commercially‐available polyetheretherketone (PEEK) resins that differ primarily in molecular weight and molecular weight distribution. Despite similar chemistry and composition, the molecular size‐dependent structural differences associated with the PEEK resins in this study are shown to influence the crystallization rate, final crystallinity, and melt rheology during processing, which subsequently affects mechanical properties, including strength, ductility, and impact resistance. These structure‐property relationships provide fundamental understanding to aid in the design and manufacturing of industrial and medical devices that leverage both the advantages common to all PEEK resins, including chemical and thermal resistance, mechanical strength, and biocompatibility, as well as more subtle differences in crystallization kinetics, melt rheology, ductility, and impact resistance. POLYM. ENG. SCI., 57:955–964, 2017. © 2016 Society of Plastics Engineers     

Antisolvent crystallization in porous hollow fiber devices

This paper examines antisolvent crystallization under a new perspective and in the unique environment offered by porous hollow fiber membrane devices. The latter are compact, extremely efficient on a volumetric basis, easy to scale up and control. Their inherent characteristics promote the creation of homogeneous concentration conditions on a scale considerably smaller than existing industrial crystallizers without the necessity of a large energy input, properties that are desirable but rarely achieved in industrial crystallizers.Mixing studies were performed to examine the maximum achievable supersaturation in porous hollow fiber devices. It was shown that they are able to offer the supersaturation levels necessary to perform antisolvent crystallization. Moreover, supersaturation is created uniformly due to the large number of feed introduction points, the membrane pores. In addition, radial mixing is substantial in contrast with traditional tubular devices and the characteristic time involved in this process is comparable to the device residence time.Porous hollow fiber antisolvent crystallization of aqueous L-asparagine monohydrate systems proved successful. Mean crystal sizes up to two times smaller compared to batch stirred crystallizers were obtained in standalone membrane hollow fiber crystallizers (MHFC) and their combinations with completely stirred tanks. The CSD was confined below for the former and for the latter, levels that are sufficient for most pharmaceutical crystalline products, for which bioavailability and formulation concerns dictate the desired CSD. In addition, porous hollow fiber devices achieved comparable or slightly higher nucleation rates with respect to batch stirred crystallizers and similar values compared to tubular precipitators. Considerable improvements can be obtained by carefully designing membrane hollow fiber crystallizers.     

crystSim: A software environment for modelling industrial batch cooling crystallization

Crystallization modelling is limited by the availability of methods to reliably predict mixing, temperature and concentration distributions, supersaturation, nucleation and growth kinetics for crystallization systems of industrial size. A new software environment for modelling batch cooling crystallization has been developed integrating crystallization and fluid dynamics. The mathematical model can reliably predict mixing in stirred vessels of a given geometry and its effect on the crystallization kinetics and crystal product properties thus reducing the cost and time required for the design and scale-up of industrial crystallizers. The paper describes the development and application of crystSim for modelling industrial crystallization in stirred tanks. The software is developed in Visual C# making full use of Object Oriented Programming (OOP) and multithreading.     

A new method for on-line monitoring of non isothermal crystallization kinetics of polymers

Summary Detailed knowledge of polymer crystallization kinetics is a mandatory requirement in modeling of transformation processes. On the other hand, techniques for investigation of crystallization kinetics are limited to cooling rates much lower than those experienced by the materials in industrial processes. A method suitable to investigate crystallinity evolution during cooling procedures carried out adopting rates comparable with those experienced by the polymer during industrial processes is thus extremely attractive. In this work a method is proposed, based on fast cooling of thin samples by means of air/water sprays and optical detection of the crystallization phenomenon. Preliminary results of crystallization temperatures detected with a device based on such a method are presented and, in the low cooling rate range, are compared favorably with calorimetric results. The comparison of experimental crystallization temperature with results of a kinetics model previously developed leads to satisfactory agreement. Received: 26 October 2001/Revised version: 12 February 2002/ Accepted: 12 February 2002     

降膜结晶法在高纯硫酸制备中的应用

现行高纯硫酸生产工艺复杂、能耗大且成本高。降膜结晶法具有绿色环保、节能和工艺简单的优势。采用减压蒸馏、降膜结晶工艺对工业硫酸进行净化提纯,可以制备出达到BV-Ⅲ级的高纯硫酸。最佳工艺条件：1）通过减压蒸馏将工业硫酸中的大部分杂质除去;2）通过降膜结晶获得粗晶体,结晶条件为初始结晶温度-5 ℃、降温步长每10 min降温0.6 ℃、结晶时间80 min、料液流量20 mL/min;3）对粗晶体进行发汗提纯,发汗条件为发汗终温 6 ℃、升温速度3 ℃/h、升温方式每10 min升温0.5 ℃。该工艺在高纯硫酸的制备方面有着广阔的应用前景。     

磷酸二氢钾结晶热力学数据的测定及应用研究

采用平衡法和激光法测定了磷酸二氢钾在水中的溶解度和超溶解度,获得了介稳区宽度数据。结合磷酸二氢钾工业装置的蒸发结晶工艺,讨论了结晶热力学实验数据在磷酸二氢钾生产中的应用,对工业结晶操作条件进行了优化。针对产量为1 000 kg/h的磷酸二氢钾工业结晶过程,得到了最佳的料液循环量、加热蒸汽用量和蒸发器的真空度分别为：50.4 m³/h、1 932 kg/h和0.067 MPa。按照所确定的工艺条件进行结晶操作,可以克服粉状结晶、获得粒度均匀的高品质结晶产品。