Environmental Research & Technology, Vol. 2 (1), pp. 26-33, 2019 Corresponding Author: lunga@unitbv.ro (Aurel Lunguleasa) Received 19 June 2018; Received in revised form 3 January 2019; Accepted 13 January 2019 Available Online 29 January 2019 Doi: ISSN: 2636-8498 © Yildiz Technical University, Environmental Engineering Department. All rights reserved. This paper has been presented at EurAsia Waste Management Symposium 2018, Istanbul, Turkey Environmental Research & Technology http://dergipark.gov.tr/ert CONFERENCE PAPER Some properties of pellets made of spruce and beech torrefied sawdust Cosmin Spirchez 1 , Nadir Ayrilmis 2 , Aurel Lunguleasa 1,* , Catalin Croitoru 3 , Mariana Pruna 4 1 Transilvania University of Brasov, Wood Processing and Wooden Products of Design Department, 500068,Brasov, ROMANIA 2 Istanbul University Cerrahpasa, Faculty of Forestry, Forest Industry Engineering Department of Wood Mechanics and Technology, Istanbul, TURKEY 3 Transilvania University of Brasov, Science and Material Engineering Department, 500068, Brasov, ROMANIA 4 Institute of Construction, Bucharest, ROMANIA ABSTRACT The paper aims to determine the physical properties (density) and calorific ones (calorific value and ash content) of pellets made of spruce and beech sawdust, thermally treated at temperatures of 170, 190 and 210 °C, for 1, 2 and 3 hours. After the thermal treatment of the sawdust, its mass loss was obtained, and compressed pellets were obtained under laboratory conditions. The results obtained from sawdust treatment indicated a weak increase in calorific value, depending on the temperature and the thermal treatment times. The final conclusion of the paper is that the thermal treatment improves the caloric properties of sawdust pellets, the beech sawdust having a higher capacity for torrefaction and compaction related to spruce sawdust. Keywords: Ash content, calorific value, thermal treatment, wooden pellets 1. INTRODUCTION Wooden pellets are obtained from sawdust with a certain granulometry, compressed to a density usually over 1.0 g cm -3 [1]. The sawdust is not cut especially for this use and is taken from other factories as timber, such as wood waste. From this point of view sawdust can be considered as a sort of wooden biomass. At worldwide level, biomass covered about 70% of the energy necessary in the year of 1870. Then, biomass lost high level in front of methane gas, coal and photovoltaic fuels. Currently, biomass continues to be the main fuel from which the energy in the countries with ongoing development is produced [2]. During the last years, there have been noticed favorable changes in the energy field, by obtaining energy from alternative non-conventional sources. The European Union wishes that the production from alternate sources reaches 20% in the year of 2020, of all the produced energy [3, 4]. Reaching this threshold implies a series of other factors favorable to development, and there are mentioned the emissions of carbon dioxide, which, in comparison with the year of 1990, until 2020 must decrease with 20% [5] according to the proposals of the European Union, by using and exploiting alternate sources of energy [6]. Using of energy crops such as Salix viminalis [7] conducted to use of whole biomass from harvesting and transforming it into pellets and briquettes with superior characteristics. Biomass is environmental friendly because the dioxide of carbon is absorbed by plants during growth and will forms a closed circuit [8], because the carbon dioxide quantity which was absorbed by plants during growth will be equal with the same quantity eliminated during the complete combustion process (Fig 1). From this point of view the use of wooden biomass in combustion has a neutral effect and all combustibles from biomass are environmental neutrally. The wooden pellets are state-of-the-art lignocellulosic energy products, obtained from small size lignocellulosic biomass (dust, sawdust and fine chips) and compacted under the form of cylinders with usual diameter of 6-10 mm [9, 10]. The pellets are engineering fuel products, which incorporate a high technology. Their dimensional uniformity, the density