Tag Archives: particle size

1722–1734 J.I. Orisaleye, S.O. Jekayinfa, R. Pecenka and T.B. Onifade
Effect of densification variables on water resistance of corn cob briquettes
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Effect of densification variables on water resistance of corn cob briquettes

J.I. Orisaleye¹, S.O. Jekayinfa², R. Pecenka³* and T.B. Onifade²

¹University of Lagos, Faculty of Engineering, Department of Mechanical Engineering, PMB 56, Akoka, Nigeria
²Ladoke Akintola University of Technology, Faculty of Engineering and Technology, Department of Agricultural Engineering, PMB 4000, Ogbomoso, Nigeria
³Leibniz Institute for Agricultural Engineering and Bioeconomy, ATB, Department of Post-Harvest Technology, Max-Eyth-Allee 100, DE14469 Potsdam, Germany
*Correspondence: rpecenka@atb-potsdam.de

Abstract:

Solid biofuels can be used in heat and power generation applications. The utilization of agricultural residues for this purpose would be of immense benefit to rural communities of developing countries where the resource is being produced. Water resistance is a crucial property for transport and storage of biomass briquettes under moist climate conditions. In this study, the effect of process and material variables on the water resistance property of corn cob briquettes was investigated. The water resistance of briquettes produced ranged between 32.6 and 94.8% for die temperature between 90 °C and 120 °C, hold time from 7.5 to 15 minutes and die pressures between 9 and 15 MPa. A higher die temperature resulted in an increase in the water resistance of the biomass briquettes. Also, increasing the hold time improved the water resistance of the briquettes. Using a particle size less than 2.5 mm resulted in higher briquette water resistance property compared to briquettes produced from particle sizes greater than 2.5 mm. It was also shown that the effect of the interaction of the temperature with particle size on the water resistance of corn cob briquettes was statistically significant (p < 0.05).

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155–164 G. Karráa, T. Ivanova, M. Kolarikova, P. Hutla and V. Krepl
Using of high-speed mills for biomass disintegration
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Using of high-speed mills for biomass disintegration

G. Karráa¹, T. Ivanova¹*, M. Kolarikova¹, P. Hutla² and V. Krepl¹

¹Czech University of Life Sciences Prague, Faculty of Tropical AgriSciences, Department of Sustainable Technologies, Kamýcká 129, CZ165 21 Prague 6, Czech Republic
²Research Institute of Agricultural Engineering, p.r.i., Drnovská 509, CZ161 01 Prague 6, Czech Republic
*Correspondence: ivanova@ftz.czu.cz

Abstract:

The need for mechanical disintegration of biomass is very current topic with regard to the requirements of an agrarian sector, beside the importance of a material’s moisture content reduction to be used in further applications. The drawbacks of commonly applied devices are the limited use of moist biomass and high energy consumption for disintegration. In collaboration with LAVARIS company, there were tested two high-speed mills LAV 400/1R with single rotor (used for a first milling) and LAV 300/2R with double rotors (used for a second milling), which were primarily designed for crushing of concrete, rubber and construction waste. The goal of the new technical solution was a disintegration of biomass on example of pine sawdust and miscanthus together with examination of simultaneous drying in order to achieve a desired fraction (particle size) and moisture content of biomass material. Experimental tests on high-speed mills have shown the following results: in case of pine sawdust about 98% of output particle size after passing through the first and second milling was smaller than 1.5 mm, and smaller than 1 mm for miscanthus (sieve analysis method was used for determination), i.e. significant reduction was achieved comparing to initial particle size. Moisture content of the materials after disintegration (first and second) decreased from 37.08% to 8.55% for pine sawdust and from 24.43% to 7.19% for miscanthus. Based on the results, it can be concluded that the mechanical disintegration of biomass by high-speed mills has a great potential to become an effective part of raw materials’ pre-treatment technology, not only in agriculture, but also in production of different types of biofuels.

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753-758 H. Mootse, A. Pisponen, S. Pajumägi, A. Polikarpus, V.Tatar, A. Sats andV. Poikalainen
Investigation of Casein Micelle Particle Size Distribution in Raw Milk of Estonian Holstein Dairy Cows
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Investigation of Casein Micelle Particle Size Distribution in Raw Milk of Estonian Holstein Dairy Cows

H. Mootse*, A. Pisponen, S. Pajumägi, A. Polikarpus, V.Tatar, A. Sats andV. Poikalainen

Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 56/5, EE51014 Tartu, Estonia; *Correspondence: hannes.mootse@emu.ee

Abstract:

The particle size of milk influences its microstructure and defines many properties of dairy products such as colloidal stability, texture etc. Differences in particle size can significantly affect milk processing especially when membrane technology is used. Aim of this investigation was to estimate casein micelle size in the raw milk of Estonian Holstein dairy cows and its variability concerning individual animals. Milk samples were collected during 12 months with the interval of 25–35 days. DLS analyses were performed using a Malvern Zetasizer Nano ZS (Malvern Instruments Ltd, Malvern, UK). Average mode of casein micelle particles size in raw milk of 44 cows was 171.13 nm with the variation range 70.1 nm and its distribution resembled a normal one. Casein micelles size mode of individual cows varied in a wide range from 148.5 (with variation range 18.2) to 194.1 (with variation range 27.6) nm which may be caused by differences in physiological and health status, stage of lactation and other factors concerning milk production.

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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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