Microwave-assisted polymer synthesis (MAPS) as a tool in biomaterials science: How new and how powerful

Lack of reproducibility, difficult and expensive scale-up and standarization of synthetic processes are the main hurdles towards the industrial production of raw synthetic and semi-synthetic polymers for (bio)pharmaceutical applications. Time- and energy-consuming synthetic pathways that usually involve the use of volatile, flammable or toxic organic solvents are apparently cost-viable and environment-friendly for the synthesis at a laboratory scale. However, they are often not viable in industrial settings especially due to the impact they have on the product cost and the deleterious effect on the environment. This has presented hurdles to the incorporation of many new biomaterials displaying novel structural features into clinics. Nevertheless, owing to unique advantages such as shorter reaction times, higher yields, limited generation of by-products and relatively easy scale-up without detrimental effects, microwave-assisted organic synthesis has become an appealing synthetic tool. Regardless of these features, the use of microwave radiation in biomaterials science has been comparatively scarce. A growing interest in the basic aspects of the synthesis of either ceramic and polymeric biomaterials has been apparent during the last decade. This article reviews the most recent and prominent applications of MW as a versatile tool to synthesize and process organic and inorganic polymeric biomaterials, and discusses the unmet goals and the perspectives for a technology that probably has the potential to make biomaterials more accessible pharmaceutical excipients and the products that involve them more affordable to patients.     

制造球形粒子的晶体聚结方法

球形聚结技术能够在同一单元操作中耦合结晶和造粒过程以制备球形晶体。相比于传统流化床造粒技术，该技术具有工艺流程短，生产成本低，产品性能优良的优势，但是同时也面临研究方法不成熟、机理复杂、工业放大和特殊结晶器型等方面的挑战。总结了针对球形结晶产品的表征技术和关键产品指标，介绍了球形聚结过程机理、数学模型和新技术设备的研究进展，并提出关于深化机理、完善模型、开发新设备方面的新思路，最后对其在工业生产尤其是制药领域的发展进行了展望。     

油气输送管焊缝无损检测技术现状与发展趋势

管道焊接在输送管中必不可少,保证焊缝的质量就显得尤为重要。超声波已经成为应用最广泛,使用频率最高,发展最快的焊缝检测技术之一,尤其近年来与电子和计算机相结合,使得未来超声波愉测技术向准确度高、自动化程度高、人为干扰小的方向发展。     

稠密气体抗溶剂沉淀的过程特征及其放大中的若干思考

稠密气体抗溶剂沉淀在微粒制备中得到广泛应用,主要用于药物、食品、化妆品和一系列精细化学品中.介绍了GAS(SAS),ASES,SEDS和PGSS等过程的流程和特征.上述工艺不仅可以制备单组分微粒,还可以制备复合微粒,为活性物质的成功缓慢释放创造了条件.相对而言,稠密气体抗溶剂沉淀的实验室规模制备微粒已较成熟,但对有些实验现象尚难给出满意的解释,操作条件与产物粒径和形态间的比较准确的关系也尚未建立,距放大到工业规模形成生产力尚有相当大的差距,主要表现在缺乏定量描述过程的模型,即使是关联模型也鲜见报道,更不要说预测模型.因此难以建立在装置尺寸和结构与过程参数以及产品尺寸和形态间的有效联系.究其原因还是应用基础研究不足,对过程实质理解不深之故.在分析过程特征的基础上,讨论了过程放大的途径以及目前存在的问题和今后开发研究中应着重关注的各个层面.     

Ultrasonic Pretreatment Transesterification for Solid Basic-Catalyzed Synthesis of Fatty Acid Methyl Esters

Generally, ultrasound irradiation is required throughout the reaction for fatty acid methyl esters (FAME, namely, biodiesel) production, which is energy-consuming and difficult to scale-up. In order to improve the industrial application of ultrasonic technology, a systematic study of ultrasonic pretreatment solid basic (Na₂SiO₃)-catalyzed transesterification for FAME production from cottonseed oil was carried out, and the effect of ultrasonic waves on the properties of Na₂SiO₃ catalyst was assessed by X-ray diffraction (XRD), Fourier transform Infrared (FTIR) and scanning electron microscopy (SEM) characterization of fresh and collected catalysts. An ultrasonic frequency of 30 kHz, ultrasonic power of 200 W and ultrasonic pretreatment irradiation time of 30 min was determined to guarantee a satisfactory degree of transesterification. The optimum production was achieved in the reaction system at 45 °C with methanol/cottonseed oil molar ratio 5:1, catalyst dosage 3% and stirring speed 350 rpm resulting in a FAME yield of above 97% after 60 min of reaction under mechanical stirring with the ultrasonic pretreatment process. The new process has a shorter reaction time, a more moderate reaction temperature, a less amount of methanol and catalyst than only the mechanical stirring process without essential damage to activity and the structure of catalyst. These results are of great significance for applying the ultrasonic pretreatment method to produce FAME.     

Scale-up study of supercritical fluid extraction process for clove and sugarcane residue

Many scale-up criteria for supercritical fluid extraction (SFE) can be found in literature. However, the studies are often divergent and inconclusive; therefore, more studies on this field are needed. The objective of the present work was to study the scale-up of SFE process focusing application to Brazilian raw materials. A laboratory scale equipment (290 mL extraction vessel) and a pilot scale equipment (5.15 L extraction vessel) were used to study scale-up of SFE for clove and sugarcane residue. The scale-up criterion adopted consisted in maintaining solvent mass to feed mass ratio constant. The criterion was successfully used for a 15-fold scale-up of overall extraction curves for both raw materials studied; yields in pilot scale were slightly higher than in laboratory scale. The criterion studied allows a rapid and simple scale-up procedure, which can be very useful for the purpose of developing SFE technology at industrial scale in developing countries where such technology is still not available at industrial level.     

超声波除碳酸钙垢的实验研究

目前,超声波是一种在工业中广泛应用的技术,可以用于油田管道的污垢清理。为了更加深入研究超声波除碳酸钙垢的效果,有必要探究超声波的参数对除垢率的影响。在实验室条件下,组装了一套超声波除垢设备,通过改变超声波的频率、辐照时间和辐照温度,分别处理Q235钢制挂片上的碳酸钙垢,采用处理前和处理后挂片质量差的方法来评价除垢效果。实验结果表明在频率为28 kHz、辐照时间为10 min和辐照温度为40℃的条件下,超声波除碳酸钙垢能力强、效果好。因此,优选出超声波不同参数之间的组合对提高除碳酸钙垢率至关重要。     

强化技术在生物柴油制备过程中的应用研究进展

在生物柴油生产过程中,由于原料油与醇不互溶,导致生物柴油生产过程中酯交换速率低,影响了生产效率。本文从强化反应过程、提高反应速率方面对以下几种强化手段进行了综述和比较：机械搅拌法、共溶剂法、超临界流体法、超声波法、水力空化法、微波法。指出水力空化设备简单,安全、高效,放大可靠,可连续化生产、工业前景良好。     

Empirical and scale-up modeling in stirred ball mills

Stirred ball mills are frequently used for ultrafine- and nanogrinding in food, pharmaceutical and chemical industry, but only few investigations have been published on empirical or scale-up modeling of stirred ball mills. Experiments have been carried out with a laboratory scale stirred ball mill. During the experiments the main technical parameters such as stirrer speed, grinding media, filling ratio, grinding time and the solid mass concentration have been systematically adjusted. The particle size distribution of mill products can be well estimated by empirical functions, so an empirical model has been prepared for the laboratory mill. The relation between the grinding fineness, grinding time and specific grinding work was represented for several materials such as pumice, andesite, limestone and tailings of ore mining industry. The power consumption of the stirred ball mill for scale-up was determined by a method based on the dimensional analysis. A new scale-up model has been presented as well by with industrial size stirred ball mills can be designed on the basis of the laboratory measurements.     

Process considerations for the scale-up and implementation of biocatalysis

With increasing emphasis on renewable feed-stocks and green chemistry, biocatalytic processes will have an important role in the next generation of industrial processes for chemical production. However, in comparison with conventional industrial chemistry, the use of bioprocesses in general and biocatalysis in particular is a rather young technology. Although significant progress has been made in the implementation of new processes (especially in the pharmaceutical industry) no fixed methods for process design have been established to date. In this paper we present some of the considerations required to scale-up a biocatalytic process and some of the recently developed engineering tools available to assist in this procedure. The tools will have a decisive role in helping to identify bottlenecks in the biocatalytic development process and to justify where to put effort and resources.     

Experimental Investigation of Ethanol Enrichment Behavior in Batch and Continuous Feed Ultrasonic Atomization Systems

The fragmentation of a liquid layer to form a fine droplet mist by high frequency ultrasonic atomization of liquids has been applied to a range of industrial applications such as fine chemical manufacturing, pharmaceutical production, and food processing. A recent development is the separation of alcohol from miscible alcohol‐water mixtures using ultrasonic atomization. In this work, the effect of high frequency ultrasonic atomization at 1.6 MHz on the enrichment of ethanol from ethanol‐water feed mixtures has been studied. Experiments for evaluating this enrichment process were conducted in batch and continuous feed processing systems. The continuous enrichment process generated product concentrations that were higher than the equivalent vapor‐liquid equilibrium curve at feed concentrations greater than 40 mol.‐% in a single stage. The role of the ultrasonic jet formed at the surface of the feed solution combined with the ethanol separation characteristics has been discussed.     

Comparison of different methods to prepare MgO whiskers

Magnesia whiskers have been made by hydrolysis of MgCl₂–KCl melt and conversion of magnesium hydroxide whiskers. The morphology of MgO whiskers was examined by SEM and TEM. Composition of products was identified by XRD. Comparisons have been made on the morphology and quality of the products by different methods. Discussions have been made on the efficiency, product quality control and scale-up feasibility of these methods. Whiskers prepared by hydrolysis have uniform diameter but other shapes of magnesia are often found. Conversion of Mg(OH)₂ whiskers to MgO whiskers is simple and easy to scale-up, but the product often has many defects caused by decomposition. Nevertheless, the single crystal structure can be reserved as revealed by electron diffraction. XRD results show that the purity of products by hydrolysis is better than that by conversion. The conversion method is more hopeful for industrial production.     

Wassermanagement als Schlüsselparameter für die Skalierung eines CO2-Elektrolyseurs

One of the major challenges in the field of electrochemical conversion of CO₂ to CO in zero-gap-electrolyzers is the scale-up to industrial relevant sizes. Despite the remarkable results achieved at laboratory scale in recent years, little progress has been made scaling up this technology. In this work, we show how controlling the water content at the cathode can help minimize flooding processes and enable the transfer of promising experimental results to larger electrolyzers.     

大环麝香香料麝香—T的工业化合成技术

麝香-T具有甜而优雅的麝香香韵及类似于天然麝香的结构,广泛用于调配各种高级日化产品。抚顺石油化工研究院在成功开发了系列FY-13复合催化剂、研究了工程放大规律、解决了过程自控问题并优化了工艺条件后,实现了麝香-T的工业化生产。开发成功的合成技术在50t/a的工业化装置上连续运转的结果表明,装置运转平稳,数据重复性好,产品收率及质量稳定,总平均收率达到了87.1％,具有良好的推广应用前景。     

Kostenkalkulation im Anlagenbau: Modell zur Bewertung der Konkurrenzfähigkeit im Entwicklungsstadium

While basic chemicals are mainly produced on an industrial scale by means of process-optimized large-scale plants, research institutes are developing biotechnological processes for the production of platform chemicals on a laboratory and pilot scale. In the context of this work, a cost calculation model for estimating the investment and operating costs of process engineering plants is presented, on the basis of which the economic competitiveness of processes currently under development can be determined. The model is usable for industrial-scale applications.     

Foam Rupture by Mechanical and Vibrational Methods

The need to destabilize foams and control their formation arises in many industrial processes. Mechanical foam breakers, mechanical vibration and ultrasonic vibration are examples of physical destructive techniques which do not suffer from the drawbacks associated with the use of chemical antifoams and defoamers. This paper reports on recent studies in this area. Two novel designs of mechanical foam breaker are presented which are superior to traditional foam breakers in controlling unwanted foaming in both bubble columns and stirred vessels. The effectiveness of mechanical and ultrasonic vibrations in destabilizing foams is shown to be governed by vibrational amplitude and frequency, and foam structure. A fundamental understanding of foam destabilization by these physical techniques is crucial to further advancement in the design of efficient and robust foam breakers and the development of enhanced non‐invasive vibrational destructive techniques.     

Modellübertragung bei partieller Ähnlichkeit

Scale-up under conditions of partial similarity . When appropriate physical properties of the system are not available, it is impossible to accurately simulate the working conditions of an industrial plant in a laboratory-scale experiment, and it then becomes necessary to resort to experiments under conditions of partial similarity. In these cases the laboratory-scale experiments must be carried out in devices of various sizes and the results extrapolated to the industrial-scale conditions. This expensive and inevitably unreliable procedure can occasionally be substituted by a systematic experimental approach based on dividing the process in question into individual parts which are then investigated separately (Examples 1 and 3), or by deliberately abandoning certain similarity criteria and checking the subsequent effects on the process as a whole (Example 2). In mixing technology, volume-related mixing power is often taken as the scale-up criterion, while in the design of bubble columns, the superficial velocity of the gas is taken as a basis. Both these cases are examples of scale-up under conditions of partial similarity, and their validity is subjected to a critical examination (Examples 4 and 5).     

低活性劣质无烟煤的催化气化

在一实验室模试固定床和流化床中首次采用工业副产碱盐廉价复合催化剂ＭＡＳ（Ｍｉｘｉｎｇ Ａｌｋａｌｉ　Ｓａｌｔ）．研究了福建低活性劣质无烟煤（Ｖｄａｆ＜５％）的催化气化过程,提出了独特的“催化气化－灰渣煅烧”（ＣＧＡＣ）的绿色工程思维,报道了气化与煅烧最佳操作条件（温度、时间与浓度）,给出了催化气化分别在模试固定床和流化床中的宏观反应动力学,指出了含碱灰渣煅烧无害化的机制与方法,实现了气化与煅烧集成式流态化的新工艺,这些对能源、环境、化学工程等诸学科的理论发展与催化气化的工业化进程均具有重要的科学价值和很大的促进作用．     

Stereoscopic visualization of the flows for pitched blade turbines

A stereoscopic film technique was used to study the particle motions in the flow fields of pitched blade turbines. The general nature of the flows and a number of specific observations are decribed for both bench and industrial scale turbines. Reasonable scale-up would require the flows in the two systems to be similar, but significant differences are found that suggest scale-up of fluid motions within such process tanks is not easily accomplished.     

条形加氢处理催化剂的工业放大问题

本文论述了条形石油馏分加氢处理催化剂工业放大的某些问题,包括：（1） 目前存在的问题；（2）工业放大基本概念；（3）工业放大效应分析;(4）工业放大基本条件；（5）产品的物化性质指标的制定。