Microsoft Word - 3 Rindyuc corectat.doc Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Volume XI, Issue 4 – 2012 19 RESEARCH ON THE INFLUENCE OF TEMPERATURE ON THE PROCESS OF GRANULATION BY EXTRUSION *Dmitro Viktorovich RINDYUK1, Svyatoslav Yuriyovich LEMENTAR1 1National university of food technologies, Ukraine, Kiev, rel_dv@ukr.net *Corresponding author Received 10 November 2012, accepted 11 December 2012 Abstract: The process of extrusion pelletizing particulate materials, such as sunflower and buckwheat husk, oak and pine chips, wheat straw and bran has been considered. It was investigated the effect of temperature of raw materials, compacting pressure and the diameter of the press-matrix on quality of fuel pellets. Keywords: temperature, particulate materials, biofuels, pelleting. 1. Introduction Production of solid biofuels is an urgent requirement for fuel and energy complex of any developed country in the world, and therefore there is a requirement for research that would allow discovering the peculiarities of the process with granulation of fuel pellets. In article [1] the problem of determining the optimal technical and technological parameters of the process of granulation extrusion was treated and was got the disperse of materials obtained depending influence of the main parameters of unit pressed pellet (Fig. 1) on the quality of the final product – the pellet. Regardless of the hardware design at process of granulation significant influence on the formation of granules of a material which has been granulated: raising of the temperature increases the density of granules, and also reduces energy consumption in the process of pressing [2]. As you know, the basic constituents of raw materials for solid biofuels are cellulose, hemicellulose and lignin. Lignin as an amorphous polymer is a kind of binding between cellulose fibrils, providing strength and rigidity of the cell wall (if cellulose with properties corresponding fixture, the lignin, which has a high compressive strength - concrete). At low temperature processes (up to 160 ° C) reaction hydrolytic decomposition of carbohydrate content and partial impolymerization of lignin to form low molecular weight fragments are predominant. Rising of the temperature of the process increases the degree of degradation of wood carbohydrates, and yet with lignin impolymerization reactions begins to compete re-polymerization his reaction. Therefore, attached to change of the temperature of the process to 150-170 ° C of lignin in wood decreaseswith increasing temperature and process of lignin increases markedly, reaching 33-36% [3-7]. Figure 1. Scheme of node compression screw extruder-granulator Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Volume XI, Issue 4 – 2012 20 The aim of this work is to study the effect of temperature on the material quality (density) of the final product (pellets) considering structural and technological parameters of the equipment for its compaction during pressing extrusion. 2. Experimental To solve this problem a multifactorial experiment is proposed and to develop mathematical and statistical model of dependence of density fuel pellets produced from sunflower and buckwheat hulls, oak and pine shavings, wheat straw and bran from raw temperature, pressure and pressing channel diameter press- matrix. ),,( dPtf where ρ - density of pellets, kg/m3; t - temperature materials, ° C; P - pressure compression, MPa; d - diameter of the press matrix. Factorial experiment of second order, which is used to describe non-linear objects, in our case, is represented by polynomial [8]: .2310 2 29 2 183217326 3152143322110 xbxbxbxxxbxxb xxbxxbxbxbxbby   Table 1 Intervals of variation Intervals of variation x1 (t, °C) x2 (P, MPa) x3 (d, м) Zero level 100 175 0,024 Step of variation 80 125 0,016 The lower level 20 50 0,008 The upper level 180 300 0,04 In Fig. 2 a scheme of pilot plant for studying the influence of temperature on the process of materials’ sealing is represented. Figure 2. Scheme of pilot plant for studying the effect of temperature on the process of sealing materials 1 - autotransformer 2 - electric heating coil, 3 - punch, 4 - press matrix, 5 – potentiometer, 6 - thermocouple, 7 – example. Pressing is performing by using of a hydraulic press to press the matrix 4 with varying diameter punch 8–40 mm at a speed of pressing 0,005 m/s. Temperature press- matrix regulate by changing the voltage filed in the electric spiral 2 of isolated press-matrix 4. The temperature of press-matrix is measured by thermocouple 6, potentiometer connected to the direct current 5. Pressure was measured by a manometer. The experiment was conducted for the following types of materials: sunflower and buckwheat husk, oak and pine chips, wheat straw and bran. The analysis of the represented dependences showed that with increasing of temperature of the raw materials from 20 to 160 ° C increasing the density of obtained granules is observed. This is due to the intensification of the process of dissolution of lignin with increasing temperature. It should be noted that a further increasing in temperature of material over 160 ° C is not appropriate because it does a little effect on increasing the density of granules, and thus leads to unnecessary energy costs. Also it is experimentally confirmed that the increase in compacting pressure and decreasing of diameter of press-matrix provides density increase granules. Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava Volume XI, Issue 4 – 2012 21 Table 2 The results of mathematical and statistical analysis of experiments Num- ber Type of raw Regression equation 1. Husk of sunflower .31,24144500462,002887,0375,59375,10 0017,031,81153567,27184,76743,155 222 dPtdPdt PtdPt   2. Buckwheat of husk .813,9013200852,00206,00773,0734,7 535,130042,0391,4229571,4787,4358,113 222 dPtdPtdP dtPtdPt   3. Shavings of pine .156,20903500605,002107,0 00289,0875,8148175,3379,5741,293 222 dPt PtdPt   4. Chips of oak .969,21766700404,00238,04375,5301,8 00114,0453,61596715,2654,6882,201 222 dPtdPdt PtdPt   5. wheat Straw .156,2010350069,002585,0328,9 00265,0813,7828792,3598,6176,35 222 dPtdt PtdPt   6. Wheat bran .656,9047200643,00118,0 00333,05,2612385,3446,2271,330 222 dPt PtdPt   a) b) c) Figure 3. The dependence of the density of granules from: a) diameter of d press matrix and temperature t of raw materials;b) compacting pressure P and temperature t of raw materials;c) compacting pressure P and diameter d press matrix. 4. Conclusions The obtained results should be used as a guideline at the organization of the technological process of granulation of dispersed materials by extrusion and at construction at related equipment. 5. 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