Prozeßintegrierter Umweltschutz beim Einsatz von Dampfstrahl-Vakuumpumpen

Integrated environmental protection in the use of steam jet vacuum pumps. At the ?cold end”? of many processes occurring under vacuum various amounts of water vapour and process steam have to be removed, together with various permanent gases, from the plant at process pressure to atmospheric pressure. The vacuum pump systems required are practically all designed to strictly separate process medium and coolant, to keep the atmospheric burden as low as possible, and also to minimise the work of compression from the point of view of overall operating costs. Thanks to their special features, steam-driven jet pumps used in conjunction with water-cooled condensers still represent a straightforward and reliable form of vacuum system. Reduction of the intermediate condenser pressure, separation of coolant and process steam, and coupling with water-ring vacuum pumps have led to combinations satisfying practically all demands with regard to good energy conversion and best possible environmental protection. In addition, process-steam driven multistage jet pumps in which condensation of working and suction steam is effected directly by cooled process fluid have also proved of value. They operate in essentially closed circulation from which only a modest flow of waste gases and heat enters the environment.     

Droplet Size Distributions of Liquid-Liquid Dispersions in Centrifugal Pumps

The generation of liquid-liquid dispersions with defined droplet size distributions is an important aspect for process equipment design. In this work, two centrifugal pumps with different impeller diameters were used to generate dispersions at selected operating points for a paraffin oil-water system. The droplet break-up phenomena within the centrifugal pumps were analyzed using a transparent pump design in combination with high-speed imaging. Droplet size distributions at centrifugal pump discharge nozzle were recorded with optical probe measurement technologies and evaluated by means of image processing using a neural network. The influence of impeller diameter, rotational speed, volumetric flow rate and dispersed phase fraction are discussed. Experimental data is correlated using fluid properties, operating data as well as centrifugal pump dimensions. The correlations developed from results of this work serve as a basis for the equipment design of centrifugal pumps.     

Experimental Characterization of a Flow‐through Pulsation Damper Regarding Pressure Pulsations and Vibrations

Pressure attenuators, especially side branch bladder‐type accumulators, for suppression of pressure pulsations in industrial fluid applications are not suitable for higher‐pressure pulsation frequencies, e.g., with centrifugal pumps. Accumulators of the flow‐through‐type promise a faster response time and thus a wider application range. The damping performance of a flow‐through pressure accumulator with respect to fluid pressure pulsations and the resulting structure‐borne noise was investigated. The influence of varying pulsation frequencies, damper precharge pressure, and damping effect throughout the piping system was evaluated. Experiments were performed in an industrial‐scale closed‐loop test facility, with both pressure pulsations and piping vibrations in the focus. The damper, characterized by means of high‐speed video analysis, proved to be capable of damping effectively the pressure pulsations and piping vibrations induced by a centrifugal pump.     

Parallel Operation of Centrifugal Pumps: Effects of Rotational Speed Differences due to Motor Slip

In industrial plants, centrifugal pumps are frequently operated in parallel configuration, not least for redundancy and operational reliability reasons. However, regarding the resulting pressure pulsations and energy consumption, this operation mode has so far not been in the focus of scientific studies. The object of the present article is to clarify the effect of parallel operation with respect to the observable pressure pulsations. Measurements were carried out with two identical centrifugal pumps operating in parallel mode in an industrial‐scale closed‐loop piping system. The results suggest that, regarding both the resulting pressure pulsations and the operating point of each pump, this operation mode is quite sensitive to smallest rotational speed deviations as they may occur due to different motor slip. The results indicate furthermore that, for minimum pressure pulsations, equal power consumptions of the two pumps are crucial, but not necessarily equal rotational speeds.     

Practical Experience in Design and Operation of Liquid‐Liquid Extraction Processes

Liquid‐liquid (L/L) extraction is a standard unit operation in the phenol‐acetone process. Special applications are the extraction of phenol from process water and the removal of phenol from recycle cumene. Besides the standard equipment such as static mixers and horizontal settlers, centrifugal pumps are used for mixing and vertical settlers are operated for phase separation. This article covers some practical experience in design and operation with focus on using centrifugal pumps, maintain mass transfer in pipes and the design of vertical settlers. Gaps in knowledge about various phenomena such as the mass transfer in turbulent L/L pipe flow are pointed out.     

Verfahren zur Verarbeitung von tierischen Rohfetten unter besonderer Berücksichtigung zentrifugaler Klär- und Trennvorgänge

Methods for Processing Animal Raw Fats with Special Consideration of Centrifugal Clarifying and Separating Processes Modern methods for processing animal raw fats are characterized by extensive application of centrifugal clarifying and separating techniques. The physical principles of such techniques as well as the design of the centrifugal equipment used, incorporating the latest developments, are dealt with in the first part of this publication. Optimum operating efficiency of centrifugal decanters functioning as pre-clarifiers is demonstrated by describing their operating principles, design, and distinguishing engineering features. For the separation of liquid mixtures and for fine clarification (?polishing”?), self-cleaning centrifugal separators are provided. Based on the constructional features of these separators, various possibilities of sediment discharge and various control systems are explained. The treatment of animal raw fat and the proper process technology are detailed in the second part of this publication. Continuous wet rendering processes are widely used in practice nowadays. Critical comments are given on the advantages of these processes as compared with the dry rendering methods. In conclusion, reference is made to environmental protection. Measures to be taken against air and water pollution are given special attention.     

Rotierende Verdrängerpumpen zur Förderung von Flüssigkeiten,breiigen und pastösen Massen

Rotating Positive Displacement Pump for Transport of Liquids, Slurries, and Pasty Masses As regards medium transport, pipe friction losses and the efficiency of the pump are the determinant factors for the motor power provided. The fundamental differences between a centrifugal pump and a positive displacement pump is made clear. Design and specific qualities of one-, two- and three spindle pumps, which are classified as rotary displacement pumps, are described. A novel classification of the fluids, related to one-, two- and three spindle pumps and a table of the application limits make it easy to select the most suitable pump.     

Die Zusammensetzung ”︁oxidierter Fettsäuren”, ihr Gehalt als Beurteilungsgrundlage für erhitzte Fette und ihre Beziehung zur Verseifungsfarbzahl

Composition of “Oxidized Fatty Acids”, Their Content as a Basis for the Evaluation of Heated Fats and Their Relationship to Saponification Colour Number “Oxidized fatty acids”? obtained from various thermally oxidized fats according to DGF method C-III 3 (68) have been investigated. Empirical formula determined from molecular weight, and C-, H- and O-content, and the possible structural formulas are discussed. During oxidation the content of ?oxidized fatty acids”? increased parallel to the increased in saponification colour number E100%, 1 cm/470 nm. Contrary to other investigations, it has been proved that the relationship between saponification colour number and “oxidized fatty acids? is not affected by the material fried. Thus it is possible to use saponification colour number in combination with acid value as basis for the evaluation of heated fats.     

Ökobilanzierung von nachwachsenden Rohstoffen am Beispiel “Palmöl”

Life Cycle Analysis (LCA) of Renewable Raw Materials Using “Palm Oil” as an Example Renewable raw materials provide ecological advantages such as renewability, protection of limited resources, unlimited availability, ease of decomposition of end-products, as well as reintegration of material. In the public discussion the above-mentioned characteristics are increasingly examined from an ecological point of view. Do they require too much fertilizer and pesticides? Are there any impacts on the ecological system such as emissions to the groundwater and damages by erosion? Within certain limits - as the social-economic sector is not taken into account - the LCA-method proves to be a means of investigation whereby ecological processes can be evaluated in a comprehensive way from “cradle to grave”. It is, however, stressed that LCA is not always carried out uniformly. Especially the LCA of renewable raw material shows considerable deviations resulting from the different evaluation of agricultural residue. The term “waste” in agricultural and industrial systems is discussed. By using the example of the Malaysian agricultural production of oil palms in plantations and palm oil in oil mills it is demonstrated that there exists an almost closed recycling system of all the agricultural residue and by-products. Furthermore, the paper deals with the closed CO₂ loop in agricultural systems.     

石油化工离心泵选用程序

为便于相关专业人员了解石油化工离心泵的各种标准,掌握选用离心泵的工作流程,本文从离心泵标准的选用、离心泵采购程序、厂商中间文件的审核以及离心泵出厂检验、包装和运输四个方面介绍了石油化工离心泵的选用程序,给出了各步骤及注意事项。     

稠油外输离心泵替代双螺杆泵探究

草桥稠油具有粘度高,密度大,外输困难等特点,稠油外输以双螺杆泵为主,因油层出砂严重导致螺杆磨损间隙增大,泵效下降较快,大修周期短、费用高,生产运行难度大。近年来,我们通过试用具有成本低廉、维护简单等特点的离心泵替代双螺杆泵,采取改进外输工艺,降低原油粘度,改善油气分离效果,改造泵前管路及过滤器,增大叶片进口处的过流面积,提高泵的抗汽蚀能力等措施,达到了泵效稳定,降低维修费用,减少能耗的目的,提高了泵站的生产运行质量。     

Korrosionserscheinungen in strömenden Medien am Beispiel von Chemiepumpen

Corrosion phenomena in flowing media, illustrated for chemical pumps. It is shown how centrifugal pumps in chemical plant are exposed to a complex superposition of (static and dynamic) mechanical and thermal stresses, of corrosion, erosion/abrasion and cavitation. Then examples of pump parts that have been operated under service conditions are shown to demonstrate appearance and origin of flow-induced, erosion- and cavitation-corrosion. Materials concepts are discussed that are able to avoid or reduce these phenomena. Several pump-like test methods are introduced that permit selection of pump materials in accordance with the practical service conditions, where hydraulic, design, and materials criteria have to be optimized to guarantee long pump lives.     

石油库如何选择离心泵

目前,国产离心泵的最高效率一般比工业发达国家同类产品低5%~10%,而实际运行效率则普遍要低10%~30%,造成这种情况最主要的原因就是泵选用不当。离心泵选用不当在石油库中十分常见,轻者造成泵在低效率下工作,重者可能造成泵的损坏。本文介绍了石油库选择离心泵的意义;详细阐述了选择卸油离心泵的具体步骤。     

分段式多级叶片离心泵轴向力的计算

介绍了国内外常用的多级离心泵轴向力计算公式 ,分别用这些公式计算了TP 4 1 1 3 P5 1 2型泵的轴向力。通过轴向力在线监测装置对此泵的轴向力进行了在线监测 ,并将计算结果与实测结果进行了比较 ,确定了比较准确的轴向力计算公式 ,从而为多级离心泵的设计提供了一定的理论依据。     

Alkohole im Erdnußaroma

Alcohols in Peanut Aroma Analysis of alcohols, esterified, free, as well as those which give rise to acids, contained in roasted peanuts is reported. Nine alcohols were isolated from the peanut variety ”?Natal Common”?. Eight alcohols could be identified by column chromatography, and UV- und IR-spectroscopy. Various acetals have been prepared.     

Kreiselpumpen und Energierückgewinnungs-Turbinen in der verfahrenstechnischen Hochdrucktechnik

Centrifugal pumps and energy recovery turbines in high pressure industrial process engineering . Centrifugal pumps have to meet many different requirements in high pressure industrial process engineering. International standards call for minimum requirements and propose solutions for various problems. Nevertheless, options remain for the operator with regard to the choice of the casing, material, and sealing variants, and to the choice of hydraulics to meet such requirements as reliability, safety, service-friendliness, economic efficiency, and investment cost. The following review presents various designs of centrifugal pumps for high pressure industrial process engineering. Furthermore, the installation of high pressure pumps in turbine operation for energy recovery is introduced.     

Produkte der Dimerisierung ungesättigter Fettsäuren I: Die Monomerfraktion der Dimerisierung reiner Ölsäure

Products of the Dimerisation of Unsaturated Fatty Acids I: The Fraction of Monomeres Obtained by Dimerisation of Pure Oleic Acid The position of methyl branches in ?isomeric stearic acids”? obtained from the monomeric fraction of the dimerisation of pure oleic acid was determined by their transformation into saturated alcanes. These compounds show mass spectra which allow a clear localisation of the position of the methyl branch. Isomeric stearic acids with a methyl branch between carbon 2 and 5 are missing. Methylheptadecanes with a branch in position 2 to 7 could be separated by GC, while the isomers with a methyl branch in position 8 and 9 turned out to be not separable. The recorded mass spectra proved that heptadecanoic acids with a branch in position 8 to 16 were present in about the same amount, while the isomeres with a branch in position 6 and 7 were produced in the course of the dimerisation only in minute amounts. Fatty acids with two methyl branches could not be detected. The fraction of the monomeres contains traces of dialkyl-substituted cyclohexenones, too. The structures of these compounds were determined by microchemical transformation of the ketones followed by analysis of the reaction mixture by GC/MS.     

离心泵调速时流量和扬程的曲线回归分析

以离心泵变频调节时的实测数据为基础,采用数理统计的方法,得到了离心泵的转速关于其流量和扬程的非线性回归方程,并检验证明了方程的有效性。     

Improving centrifugal pump efficiency by impeller trimming

Centrifugal pumps as inevitable part of any desalination plant are significant consumers of energy. Due to high capacities of desalination plants, efficient operation of all their components, including centrifugal pumps is very important. It is often found that centrifugal pumps do not operate in their optimal points for various reasons. One of the methods to improve efficiency of centrifugal pump is proposed here. Impeller trimming is a common practice performed by pump manufacturers and users when it is necessary to adjust the centrifugal pump head and flow to the actual needs. The trimmed pump is not strictly similar to the initial pump because only a few parameters are modified, while all the others remain unchanged. In spite of this, the assumption of valid similarity was made here and examined through a series of experiments. A centrifugal pump impeller of low specific speed (n_sp = 19,745 r.p.m.m^0.75 s^− 0.5) was trimmed and tested successively. For this particular pump, the influence of disregarded similarity can be estimated to ± 3.94% for the pump head and to ± 5.24% for the power, both with a 95% statistical certainty.     

Großtechnische Feinfraktionierung von Kokos- und Palmkernfettsäuren aus der Sicht des Praktikers II

Technical Fine Fractionation of Coconut and Palm-Kernel Fatty Acids from Practical Viewpoint II The first part of this work reviewed the technological possibilities for the optimum separation of coconut and palm-kernel fatty acids. The present communication deals with the factors, such as plant design and processing, which are of major significance for the processing cost and processing behaviour. In this context, the influences of the quality of raw material and that of the residue, which is mainly composed of the unhydrolyzed oil, on the properties of fatty acid distillate were studied. Further discussions concern the corrosion behaviour of the currently available economical materials of construction and the permissible thermal stress from the viewpoint of product stability. In both cases, the effects of time as well as temperature were studied. Since hot fatty acids are prone to oxidative deterioration, severe loss of quality may occur if adequate precautions are not taken. In this respect, the experience gathered during the last decade on the use of pumps without stuffing box for the operation of falling film evaporators with forced circulation is reported. Finally, it is shown that the plants which are conceived and their mode of operation was worked out by the author easily fulfil the requirements concerning environmental safety with respect to waste water, air, and noise.