Tag Archives: milling

1427-1434 L. Mezule, M. Strods and B. Dalecka
Influence of Mechanical Pre–treatment on Fermentable Sugar Production from Lignocellulosic Biomass
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Influence of Mechanical Pre–treatment on Fermentable Sugar Production from Lignocellulosic Biomass

L. Mezule*, M. Strods and B. Dalecka

Riga Technical University, Faculty of Civil Engineering, Research Centre for Civil Engineering, Water Research Laboratory, Kipsalas 6a–263, LV–1048 Riga, Latvia *Correspondence: linda.mezule@rtu.lv

Abstract:

Mechanical pre-treatment of lignocellulosic biomass has been extensively applied in biofuel production despite its high energy requirements. To balance the consumed energy with the energy produced, careful selection and evaluation of pre-treatment parameters, equipment and desired outcome is needed. The study aims to determine optimal hay and barley straw biomass particle size in view of sugar yields, energy consumption and treatment time. The results show that there is no significant difference (p > 0.05) in sugar yields from hay biomass with particle sizes 0.25 mm, 1 mm and 10 mm. Energy requirements for the production of 1 kg of sugar from hay range from 1.8–10.7 MJ. At the same time barley straw proved to be inappropriate for sugar extraction due to low sugar yields (below 40 mg g-1 dry mass) and high energy consumption (18.5–76.2 MJ to produce 1 kg sugar). Thus, after the careful selection of biomass, mechanical pre-treatment followed by enzymatic hydrolysis can be an effective technique in biofuel production from biomass.

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263-268 T. Leemet,, J. Allas, M. Madissoo, E. Adoberg and R. Saar
Testing a method for evaluating the performance of coatings on end mills in semi-industrial conditions
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Testing a method for evaluating the performance of coatings on end mills in semi-industrial conditions

T. Leemet¹,*, J. Allas¹, M. Madissoo¹, E. Adoberg² and R. Saar³

¹Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56, EE51014 Tartu, Estonia; *Correspondence: Tonu.Leemet@emu.ee 2 Institute of Physics, University of Tartu, Riia 142, EE51014 Tartu, Estonia 3Department of Materials Engineering, Faculty of Mechanical Engineering, Tallinn University of Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia

Abstract:

Milling remains as one of the most versatile machining operation in manufacturing. Machine tools with several axis of movement and precise numerical controls are able to manufacture complex geometries for medical implants, parts needed in space technology etc. The quality of the workpiece and the cost of manufacturing are influenced by many factors, tool selection being one with considerable impact. Depending on the specific type of milling operation and the material of the billet, the coating of the cutting tool can have a significant influence to quality and cost of the process. In this study an attempt is made to develop a methodology for relatively simple but effective means for evaluating the suitability of a coating for a particular milling operation. Flank wear width is generally recognized as the key indicator for tool life criteria. Relatively complex geometry of the end mill makes the flank wear measurements somewhat difficult. In practice several other indication of tool wear are used: changes in the spectra and volume level of the sound emitted from the cutting process, shape and color of the chips, quality of the manufactured surface and the presence of the burrs. In this work the flank wear measurements by optical measurements are analyzed and reasoned, additional information is found by scanning electron microscopy. Three industrial PVD coatings – TiAlN, naCo and nACro were tested.

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155-164 A. Menind and A. Normak
Study on Grinding Biomass as Pre-treatment for Biogasification
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Study on Grinding Biomass as Pre-treatment for Biogasification

A. Menind¹ and A. Normak²

¹ Institute of Technology, Estonian University of Life Sciences,
56 Kreutzwaldi Str., EE51014 Tartu, Estonia; e-mail: andres.menind@emu.ee
² Institute of Agricultural and Environmental Sciences,
Estonian University of Life Sciences, 5 Kreutzwaldi Str., EE51014 Tartu, Estonia

Abstract:

Six different samples were collected from local farms in Tartu County in Estonia. Based on preliminary results of fibre tests, four samples with different lignin content were chosen for grinding and biogasification experiments. Next, knife mill and laboratory scissors were used for particle size reduction. The knife mill was used with bottom screen sizes 0.5 mm, 4 mm and 10 mm. With scissors the hay was cut into 2…3 cm pieces. Sieve shaker and Easy Sieve software were used for particle distribution analysis. Biogas potential was determined for different hay samples. Cumulative biogas production was calculated by pressure increase in gas phase of bottles according to ideal gas law. We are going to show in what way the cutting impacts biogas yield. Negative correlation between biogas yield, particle size and lignin content is significant for most hay samples analysed.

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459-464 A. Lisowski, J. Klonowski and M. Sypuła
Comminution properties of biomass in forage harvester and beater mill and its particle size characterization
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Comminution properties of biomass in forage harvester and beater mill and its particle size characterization

A. Lisowski, J. Klonowski and M. Sypuła

Department of Agricultural and Forest Machinery, Warsaw University of Life Sciences– SGGW, Nowoursynowska 166, 02787 Warsaw, Poland;email: aleksander_lisowski@sggw.pl

Abstract:

It was found that the differences in the distribution of particle length were the species feature of energetic plants. The length distribution of comminuted willow particles showed the highest mean value and good regularity, while the topinambour mixture was the shortest and most irregular in the mixture of energetic plants. Connectivity between mean values of particle length plants broken up in the forage harvester and in the beater mill, calculated by geometric mean method and according to Rosin-Rammler-Sperling-Bennett model, was very high, as testified by square correlation values, which amounted to 79.4 and 97.8% respectively. The research allows proving the practical possibility of using the RRSB model to determine the amount of separated material meeting dimension requirements for production of formed fuels.

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