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1.
《Plastics, Additives and Compounding》2003,5(6):39
New underwater and strand pelletizing technologies are now available to the compounder. Plastics Additives & Compounding reports on some recent activities at a number of companies active in pelletizing. 相似文献
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《Plastics, Additives and Compounding》2003,5(6):38
New underwater and strand pelletizing technologies are now available to the compounder. Plastics Additives & Compounding reports on some recent activities at a number of companies active in pelletizing. 相似文献
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The importance of extractives and storage for sawdust as raw material for wood pellet production was analyzed. Sawdust prepared from eastern white pine (Pinus strobus L.), white oak (Quercus alba L.) and yellow-poplar (Liriodendron tulipifera L.) together with two commercial raw materials were extracted with acetone or stored at 60 °C for 21 days. The effects of the treatments were measured on the pellet strength, and with respect to the energy use requirements of a commercial pellet mill using laboratory dies and methods to measure the different stages of the pelletizing process individually. The results showed that removal of the extractives significantly increased the pellet strength and the energy requirements in all stages of the pelletizing processes corresponding to the samples extractives content, whereas the effect of the storage treatment was indefinite. The study indicates that extractives act as plasticizers and lubricants and thereby decrease the energy requirements for the pelletizing process. On the other hand, extractives seem to prevent close contact between the bonding sites of the lignocellulose particles and thereby decrease the pellet strength. Differences in extractives content can therefore explain differences in pellet mill energy consumption and capacity when raw materials from different wood species are used. The effect of storage with respect to particle surface accumulation of extractives may have little importance compared to the total amount of extractives in the raw material. 相似文献
4.
《Plastics, Additives and Compounding》1999,1(4):30-33
A wide range of pelletizers is available for the compounder to convert the melt from the extruder into an easily handled form. This month Plastics Additives & Compounding takes a look at some of the new developments in pelletizing. 相似文献
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New underwater and strand pelletizing technologies are now available to the compounder. Plastics Additives & Compounding reports on some recent activities at a number of companies active in pelletizing. 相似文献
6.
Fuel pellets from biomass: The importance of the pelletizing pressure and its dependency on the processing conditions 总被引:4,自引:0,他引:4
Wolfgang Stelte Jens K. Holm Anand R. Sanadi Søren Barsberg Jesper Ahrenfeldt Ulrik B. Henriksen 《Fuel》2011,90(11):3285-3290
The aim of the present study was to identify the key factors affecting the pelletizing pressure in biomass pelletization processes. The impact of raw material type, pellet length, temperature, moisture content and particle size on the pressure build up in the press channel of a pellet mill was studied using a single pellet press unit. It was shown that the pelletizing pressure increased exponentially with the pellet length. The rate of increase was dependent on biomass species, temperature, moisture content and particle size. A mathematical model, predicting the pelletizing pressure, was in good accordance with experimental data. It was shown that increasing the temperature resulted in a decrease of the pelletizing pressure. Infrared spectra taken from the pellets surface, indicated hydrophobic extractives on the pellet surface, for pellets produced at higher temperatures. The extractives act as lubricants, lowering the friction between the biomass and the press channel walls. The effect of moisture content on the pelletizing pressure was dependent on the raw material species. Different particle size fractions, from below 0.5 mm up to 2.8 mm diameter, were tested, and it was shown that the pelletizing pressure increased with decreasing particle size. The impact of pelletizing pressure on pellet density was determined, and it was shown that a pelletizing pressure above 200 MPa resulted only in minor increase in pellet density. 相似文献
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Robert Samuelsson Mikael Thyrel Michael Sjstrm Torbjrn A. Lestander 《Fuel Processing Technology》2009,90(9):1129-1134
Sawdust of conifers as a by-product from saw mills is the most commonly used biomaterial for pellet production in Sweden today. Experiences from the biofuel pellet industry indicate that different biomaterial properties influence the final pellet quality. A systematic study was conducted where five factors were varied according to a two level fractional factorial design. The factors were: tree species (Scots pine, Norway spruce); origin of growth-place (latitudes 57 and 64°N); storage time of sawdust (0 and 140 days), moisture content (9 and 12%) and steam treatment (2 and 6 kg/h). The measured responses bulk density and mechanical durability represented the pellet quality while the press current and the fines produced in the pelletizing process were measures of the pelletizing property.The results showed that low moisture content and long storage time resulted in increased bulk densities and press currents. For mechanical durability and fines, a long storage time and intermediate moisture contents were found favourable. In addition, indications were found that the reduction of fatty and resin acids during the storage also influenced the pelletizing properties and the pellet quality. 相似文献
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A. P. Amosov A. G. Makarenko A. R. Samboruk B. S. Seplyarskii A. A. Samboruk I. O. Gerasimov A. V. Orlov V. V. Yatsenko 《International Journal of Self-Propagating High-Temperature Synthesis》2010,19(1):70-77
Such a simple technological trick as pelletizing (granulating) green powder mixtures (popular in conventional powder technology)
has seldom been used in SHS technology. We have demonstrated that pelletizing green powder mixtures can markedly affect the
parameters of various SHS reactions (SHS in a mode of infiltration-mediated combustion, SHS with a reduction stage, combustion
of thermit mixtures, SHS in aluminum melt) and properties of their products. 相似文献
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D. Prieur F. Lebreton P.M. Martin A. Jankowiak T. Delahaye P. Dehaudt P. Blanchart 《Journal of the European Ceramic Society》2012,32(8):1585-1591
In the framework of Partitioning & Transmutation (P&T), U1?yAmyO2±x materials are promising fuels for Am recycling. In this context, these materials were fabricated in the ATALANTE facility by a process which consists of pelletizing and reactive sintering. Since it was effective in studies conducted on UO2+x, sintering in overstoichiometric conditions was investigated. In this work, three Am contents (10, 20 and 30%) and four temperatures (from 1000 to 1300 °C) were studied. It was shown that low-density and multiphasic compounds were obtained. Moreover, XRD and XAFS analyses pointed out that the total reduction of Am(+IV) to Am(+III) and solid solution formation occur during sintering at temperatures inferior to 1300 °C. Although previous studies on UO2+x showed that high oxygen potential enhanced the diffusion process, this work proved that this effect is clearly modified by the presence of Am. Finally, sintering in overstoichiometric conditions is not yet suitable for Am-bearing fuel fabrication. 相似文献
15.
The influence of raw material characteristics on the industrial pelletizing process and pellet quality 总被引:1,自引:0,他引:1
Mehrdad Arshadi Rolf Gref Paul Geladi Sten-Axel Dahlqvist Torbjörn Lestander 《Fuel Processing Technology》2008
Industrial pelletizing of sawdust was carried out as a designed experiment in the factors: sawdust moisture content, fractions of fresh pine, stored pine and spruce. The process parameters and response variables were energy consumption, pellet flow rate, pellet bulk density, durability and moisture content. The final data consisted of twelve industrial scale runs. Because of the many response variables, data evaluation was by principal component analysis of a 12 × 9 data matrix. The two principal component model showed a clustering of samples, with a good reproducibility of the center points. It also showed a positive correlation of energy consumption, bulk density and durability all negatively correlated to flow rate and moisture content. The stored pine was more related to high durability and bulk density. The role of the spruce fraction was unclear. The design matrix, augmented with the process parameters was a 12 × 6 matrix. Partial least squares regression showed excellent results for pellet moisture content and bulk density. The model for durability was promising. A 12 × 21 data matrix of fatty- and resin acid concentrations measured by GC–MS showed the differences between fresh and stored pine very clearly. The influence of the spruce fraction was less clear. However, the influence of the fatty- and resin acids on the pelletizing process could not be confirmed, indicating that other differences between fresh and stored pine sawdust have to be investigated. This work shows that it is possible to design the pelletizing process for moderate energy consumption and high pellet quality. 相似文献
16.
就装置从国外引进的聚丙烯粉料挤压造粒系统的工艺及在生产中遇到的问题进行分析,提出有针对性的解决方法;同时对不同牌号下运行参数进行比较归纳,为该系统优化操作提供指导。 相似文献
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Alejandro Robau-Sánchez Alfredo Aguilar-Elguézabal Luis de la Torre-Sáenz Daniel Lardizábal-Gutiérrez 《Carbon》2003,41(4):693-698
The radial distribution of porosity in spherical activated carbon particles and its relationship to both activation temperature and conversion of the reaction C-CO2 are discussed. Char spheres, obtained by pelletizing Quercus agrifolia powdered char, were activated using CO2 as activating agent at 820 and 860 °C. For both temperatures, the gasification reaction was run until the desired conversion (30, 50 and 70%) was reached. The activation process was performed using TGA apparatus. The porosity of the samples was measured by physical adsorption of nitrogen at −196 °C. BET and Dubinin-Raduskhevich equations were used to analyse the results. From each activated carbon sphere several samples were prepared, corresponding to different layers of the sphere; an outer layer, a middle layer and the core of the particle. From these results, the radial porosity evolution as a function of activation temperature and reaction conversion was obtained and a mathematical expression that correlates pore volume evolution and reaction conversion is proposed. 相似文献
18.
Edward L. Steward 《乙烯基与添加剂工艺杂志》2006,12(2):83-86
This article discusses, in general terms, several approaches to producing highly filled plastics. Emphasis is on wood flour, with polyolefins as an example. Processing other highly filled polymer and filler choices follows the same logic. Successful approaches include the single screw machine being fed pre‐pelletized material. A large pelletizing twin screw compounder selected for compounding for its output rate isolates the complexities of the compounding step from the profile lines, which have their own unique challenges, such as sizing and cooling the part at good quality and with good tolerances. Operating a few big pelletizing twin screw machines would allow the simple single screw lines of various sizes to run at decent efficiencies on big or small profiles. Since not one machinery approach has monopolized this application to date, some of the major processing and equipment comparisons are discussed. J. VINYL. ADDIT. TECHNOL. 12:83–86, 2006. © 2006 Society of Plastics Engineers 相似文献
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《Plastics, Additives and Compounding》2000,2(1):21-23
Some basic research in polymer behaviour during the pelletizing by Rieter Automatik has led to an improvement in the quality of pellet cuts. Along with other innovations, the development has now been incorporated in the company's latest range of strand pelletizers for the compounding industry. Mark Holmes reports. 相似文献
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基于CFD?DEM耦合方法,研究了颗粒在水室内的流动状态,分析了不同刀盘转速、粒子水通入量和水室出口角度对造粒过程的影响,发现提高刀盘转速、增加粒子水通入量和水室出口倾斜一定的角度都有利于水室内颗粒的排出。进一步研究了颗粒与碎屑在水室内的流动,发现在水室出口处二者的流动基本呈现出一定的分离角度。 相似文献