Šumarski list, Vol. 142 No. 3-4, 2018.
Izvorni znanstveni članak
https://doi.org/10.31298/sl.142.3-4.3
Contribution to the research on wood pellet characteristics from Turopolje area
Branimir Šafran
; Faculty of Forestry, University of Zagreb
Matija Jug
; Faculty of Forestry, University of Zagreb
Kristijan Radmanović
; Faculty of Forestry, University of Zagreb
Marijan Hasan
; Faculty of Forestry, University of Zagreb
Kristijan Augustinović
; Faculty of Forestry, University of Zagreb
Krešimir Vučković
; University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture
Stjepan Risović
; Faculty of Forestry, University of Zagreb
Sažetak
The paper deals with some quality characteristic of wood pellets from Turopolje area. The samples of pedunculate oak (Quercus robur L.), European hornbeam (Carpinus betulus L.), narrow-leaved ash (Fraxinus angustifoliaVahl.), European alder (Alnus glutinosa L.) and black poplar (Populus nigra L.) were collected. Collected and debarked samples were crushed by a mill with knives to 2.00 mm granulation. The content of water, ash and calorific value were examined on samples. The ash content was determined separately for the bark and the wood. The ash content in the barks shows a high rate in pedunculate oak which is 13.64 % and hornbeam with 11.91 %, while in other species the ash content in a bark is between 7 and 10 %. The ash content of a debarked wood shows the following values: 0.63 % for the oak, 0.50 % for the ash, 0.46 % for the hornbeam. Values of the ash content in the alder and the poplar were 0.4 %. Results indicate the need for debarking in pellet production in order to obtain the quality of class A1 and A2 pellet. By determining the calorific value the best results were determined in the black poplar sample which is 19.63 MJ/kg, and the lower value was measured in hornbeam sample 18.94 MJ/kg. Furthermore, the mentioned samples were mixed and 3 mixture groups were formed. The share of hard broad-leaved trees of oak, hornbeam and ash in each individual mixture was 60 %,while in the remaining 40 %,alder (20 %) and poplar (20 %) equally participated. Formed material mixtures APA (ash 60 : poplar 20 : alder 20), OPA (oak 60 : poplar 20 : alder 20) and HPA (hornbeam 60 : poplar 20 : alder 20) were pressed into pellets by hydraulic laboratory press in 2 forces
(3.0 and 6.0 kN) and 2 temperatures (150 and 200 °C). After pressing, pellets were left for 15 days to stabilise in dimension and their dimension and density were determined. Then, pellets were checked for pressure strength in a radial direction by a testing machine. Pellets from all the mixtures, pressed by a force of 6.0 kN at 200 °C showed a high density in the range from 1 207 – 1 234 kg/m3. Pellets of basic ash mixture at force of 3.0 kN and at 200 °C gave high density≈ 1200 kg/m3, while the smallest density was generally given by pellets of basic hornbeam mixture in all pressing regimes. The results of pressure strength in radial direction give best results in pellets pressed at 6.0 kN and 200 °C which is 13.59 MPa with the basic ash mixture, 11.1 MPa with the basic oak mixture and 9.06 MPa of basic hornbeam mixture.
If the pressure strength of a pellet is considered collectively according to the mixture, pellets made from the mixture of ash, poplar and alder give significantly better results in comparison to other two mixtures.
Ključne riječi
wood pellets; ash content; calorific value; pellet density; pressure strength
Hrčak ID:
199395
URI
Datum izdavanja:
30.4.2018.
Posjeta: 1.861 *