A study of the determination of peroxides in fats

Summary The Kokatnur-Jelling method as modified by Lingenfelter for the determination of peroxides in animal fat has been found to agree satisfactorily with other methods now in use. The modified method involves a microtitration in a homogeneous medium (isopropanol) and has the additional advantages of being both simple and rapid. A statistical analysis of the peroxide values shows that the reaction time and temperature and the sample size must be standardized to obtain reproducible and reliable results. Close adherence to reaction specifications such as five minutes at 80°C. or seven minutes at 75°C. is necessary. Three minutes is too short a reaction time. The individual fat sample should contain no more than 50 microequivalents of peroxygen to avoid depression of the peroxide value. This publication is based on one of a series of studies supported largely by the Buffalo Niagara Electric Power Corporation, Carrier Corporation, Central Hudson Gas and Electric Corporation. Central N. Y. Power Corporation, Consolidated Edison Company of N. Y., Inc., Long Island Lighting Company, N. Y. Power and Light Corporation, N. Y. State Electric and Gas Corporation, Rochester Gas and Electric Corporation, and the Staten Island Edison Corporation. The studies are being carried out under the direction of a committee appointed from the staff of Cornell University, consisting of the following members: Dr. L. A. Maynard, chairman, Dean E. Lee Vincent, Dr. C. E. F. Guterman, Dr. A. J. Heinicke, Dean S. C. Hollister. The authors gratefully acknowledge the assistance and interest of Drs. Walter L. Nelson, S. E. Smith, and H. L. Lucas in the experimental design and statistical analysis.     

浅谈石灰竖窑技术改造

老式机械化石灰竖窑装备落后,其生产出的石灰质量低,已满足不了冶炼优质钢种生产的需求。针对这种情况．马钢股份公司第三钢轧总厂对该种窑进行了技术改造。改造后的石灰竖窑能生产出优质的活性石灰,采用活性石灰炼钢,可缩短冶炼周期,降低吨钢石灰消耗。     

ADAPTATION OF TUNNEL AND CAR KILNS TO FIRING REFRACTORIES1

The success of tunnel kilns in a given industry is largely determined by the choice of the type best suited to the requirements of that industry. This paper discusses the adaptation of the various types of tunnel kilns to firing glass house refractories, clay, fire brick and silica brick.     

NOTES ON FIRING TERRA COTTA1

Some notes are given on the firing behavior of a 14-foot diameter muffle type terra cotta kiln, using coal as a fuel. The need of more data on periodic fired kilns in all branches of the ceramic field is stressed.     

SOME DATA ON THE WHITEWARE INDUSTRY OF WEST VIRGINIA1

Most of the usual types of whiteware are manufactured in West Virginia by 24 different firms. Data are given on the kinds of body raw materials used, and their geographic sources; the materials used for glazes; lawn meshes used; number and kinds periodic bisque kilns and glost kilns; number of car tunnel bisque and glost kilns; horns kilns are on fire and the cones reached in each of the various types of whiteware.     

USE OF SMALL QUICK-ACTING KILNS FOR INSTRUCTION AND RESEARCH1

Considerable experience with small, quick-acting kilns in the laboratory, both for instruction and research, has indicated the distinct advantages of this type of kiln. By the use of an insulating refractory the mass of the kiln can be reduced to less than one-tenth of that usually employed, which makes rapid heating possible without great expenditure of fuel. Two types of kilns are described which have given good service for a considerable length of time. Temperatures as high as 2600°F can be obtained with atmospheric burners and temperatures up to 3000°F with blast burners.     

THE HEAT-BALANCE STUDY OF CERAMIC KILNS1

The elements of the heat-balance study and calculation of the thermal efficiency of ceramic kilns are summarized, and an outline of a heat-balance method is given. The CO₂ in the flue gases of the kilns studied was measured automatically and continuously by an electric CO₂ meter making use of the thermal conductivity method, and some of the resulting CO₂percentage curves are given and interpreted. A complete heat-balance of a 30-foot round downdraft facebrick kiln fired with wood is given, together with various data and conclusions on the use of wood in firing ceramic kilns. A complete heat-balance of a Hoffman continuous coal fired kiln is given, together with temperature-gradient curves and other data of this and two other Hoffman kilns.     

回转窑传热过程数学模型的研究现状及其发展

介绍了各种回转窑传热过程数学模型的概况及其特点,并综述了国内外有关回转窑传热过程数学模型的研究现状及其发展。结合当前的实情,对回转窑传热过程数学模型研究领域中需进一步改进和完善的方面提出了一些建议,并展望了回转窑传热过程数学模型的发展趋势。     

Comparison of discrete elemental modelling to experimental data regarding mixing of solids in the transverse direction of a rotating kiln

Finnie et al. [Finnie, G.J., Kruyt, N.P., Ye M., Zeilstra, C., Kuipers, J.A.M., 2005. Longitudinal and transverse mixing in rotary kilns: a discrete element method approach. Chemical Engineering Science 60, 4083-4091] developed a discrete elemental model to simulate the mixing of solids in a rotary kiln. It is interesting to analyse and compare their results to those obtained through experimental observations such as those by Henein et al. [Henein, H., Brimacombe, J.K., Watkinson, A.P., 1983. Experimental study of transverse bed motion in rotary kilns. Metallurgical Transactions B 14B, 191-205] Van Puyvelde et al. [Van Puyvelde, D.R., Young, B.R., Wilson, M.A., Schmitd, S.J., 1999. Experimental determination of transverse mixing kinetics in a rolling drum by image analysis. Powder Technology 106, 183-191; 2000. Modelling transverse mixing in a rolling drum. Canadian Journal of Chemical Engineering 78, 635-642] and Mellmann [Mellmam, J., 2001. The transverse motion of solids in rotating cylinders—forms of motion and transition behavior. Powder Technology 118, 251-270].     

耐火材料窑炉设计中的优化选材

根据耐火材料工业几种主要窑炉的使用条件 ,结合耐火材料的性能特征 ,概括总结了耐火材料工业几种主要窑炉优化选材的原则 ,并举例进行了说明。     

ADVANTAGES AND USE OF A CO2 METER ON A FORCED DOWNDRAFT PERIODIC KILN AS TO TEMPERATURE DISTRIBUTION1

Notes on forced downdraft system used on dry-pressed electrical porcelain fired to cone 12 flat are discussed. The type and general construction of the kiln, heat distribution, fuel used per firing, and the use of the CO₂ meter for adjusting the draft for various conditions to get uniformly fired kilns, both as to time of firing and appearance of ware, are given.     

对潮州“龙窑”的探讨

龙窑是优良古窑种之一,潮州龙窑在潮州陶瓷文化占据很重要的位置,并在潮州地区广泛分布。其传统的生产工艺,特别是烧成过程的一些特性,是历代陶瓷窑炉技术改造的基础,可以说,潮州历代陶瓷业的发展,潮州龙窑功不可没。     

Lipid composition of rat superior cervical ganglion

Excised rat superior cervical ganglion were incubated in Krebs-Ringer solution, freeze-dried, and lipids extracted with chloroform: methanol (2∶1) v/v. Chromatography of lipid extracts in three separate thin layer chromatography solvents was accomplished on a single thin layer chromatography plate coated with acid-washed Silica Gel H. Individual lipids were eluted from the silica gel using a modified Swinny filter holder technique and transesterified with methanolic-BF₃. Fatty acid methyl esters were separated and quantitated by gas liquid chromatography, while phospholipids were determined with a Malachite green dye organic phosphorus assay. Quantitation of neutral lipids was accomplished with a micro Liebermann-Burchard technique and sphingolipids estimated colorimetrically as free sphingosine. The composition of lipids from freezedried rat ganglia resembles the lipid composition of rat brain. Phosphatidylcholine and phosphatidylethanolamine represent 76% of the glycerolphosphatides. The sphingolipids were comprised primarily of sphingomyelin with moderate levels of cerebroside and sulfatide. Cholesterol was the predominant neutral lipid. The major phospholipid fatty acids included palmitic, stearic, and oleic acids. Sumbitted in part as a partial requirement for the Ph.D. degree, State University of New York at Buffalo, Buffalo, N.Y.     

De-dusting Filter Bags Reduce Indian Petcoke Mill Emissions

BWF Envirotec has installed more than 400 filter bags in a pulse jet clean filter system at an Indian industrial mill producing petroleum coke, a fuel commonly used in rotary kilns for cement production. The pulse jet filter separates the fine grain ‘petcoke’ product from the exhaust gases escaping out of the mill. The installation by the German-based company has reduced the mill’s measured emissions over the last nine months to under 10 mg/Nm³.     

Firing lightweight Dinas in a tunnel-type kiln

Conclusions The best type of stacking has been ascertained for lightweight dinas on tunnel-type kiln cars.The dinas can be fired in tunnel-type kilns together with ordinary dinas without altering the firing conditions.The lightweight dinas fired in the tunnel-type kilns included the larger types PM-17 and PM-20, so there is no doubt that standard size lightweight dinas can also be fired in these kilns.The satisfactory results of the experiments have enabled the plant to begin firing this dinas in tunnel-type kilns.     

Mean residence time and hold-up of solids in rotary kilns

The influence of operational variables on the mean residence time (MRT) and hold-up of the solids in rotary kilns has been investigated by many researchers. However, their reports on the influence of the feed rate on MRT, for example, are not consistent with one another. In this study, experiments are conducted on a 400 mm ID pilot kiln with a cylindrical discharge dam. Sand is used as the testing solids. MRT and the hold-up are measured under various feed rates and rotation speeds. Experimental results indicate that MRT increases slightly with the feed rate, and that the gradient is smaller at high rotation speeds. The hold-up shows a near-linear increase with the mass of feed per kiln rotation. The experimental data are then used to test equations provided by different researchers for the prediction of MRT. Comparisons show that, results of the empirical equation from Sullivan, J.D., Maier, C.G., Ralson, O.C. [1927. Passage of solid particles through rotary cylindrical kilns. U.S. Bureau of Mines Technical Paper No. 384.] agree well with measurements for the cases of low kiln loadings, while the numerical model of Saeman, W.C. [1951. Passage of solids through rotary kilns: factors affecting time of passage. Chemical Engineering Progress 47, 508-514.] gives good predictions over the entire range of parameters considered.     

新型宽体节能隧道窑的开发

通过对国外陶瓷隧道窖的研究，开发出了一条既不同于我国传统窑又区别于引进窑的新型宽体节能隧道窑。     

Evolution of fluorine emissions during the fast firing of ceramic tile

The present paper examines the emission–adsorption phenomena of fluorine compounds in various ceramic tile body compositions with different fluorine and calcium contents, processed by fast firing cycles in an electric laboratory batch kiln and in continuous fast-cycle industrial combustion kilns (roller kilns). In the roller kilns, fluorine emission was monitored by analysing the fluorine content in both solid and gas samples throughout the kilns.It was found that fluorine emission during firing in air atmosphere in the laboratory batch kiln began at temperatures above 800 °C and increased progressively up to peak firing temperature. In the roller kilns, however, the emissions started at lower temperatures and decreased in certain kiln zones. This decrease indicates that there are regions in these kilns in which fluorine is adsorbed rather than emitted by the material being processed.A fluorine adsorption process is thus shown to occur in the preheating stage in the roller kilns, despite the rapid heating rate. However, encouraging this adsorption process in order to foster the formation of crystalline phases is ineffective in abating fluorine emissions when ceramic tiles are fired at peak temperatures exceeding 1100 °C.