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Biomass energy for heating is going to be part of the spectrum of renewable energy sources. However, biomass combustion produces emissions of various pollutants with negative effects at both local and global scales. To reduce some of the locally important pollutant load, thermally treated biomass fuels may offer a partial solution. In this study, two biomass feedstocks, i.e., spruce chips and rapeseed straw, were thermally treated at 300 °C to produce biochars. Subsequently, both original materials and biochars were burned in a 25 kW retort combustion device. In both cases, the biochar showed lower emissions of carbon monoxide and nitrogen oxides, usually almost across the whole range of tested combustion conditions. In total, for the emission production per unit of net calorific value, the spruce biochar showed reductions in CO and NOx productions of 10.8% and 14.5%, respectively. More importantly, in rapeseed straw biochar, the difference was more pronounced. The total production was reduced by 28% and 42%, again in CO and NOx emissions, respectively. [ABSTRACT FROM AUTHOR]

The objective of this work was to investigate the rate of knife wear during the beech wood chipping process and to evaluate the changes in the chemical and microscopic structure of wood. A knife coated with AlCrN was selected for the study. This coating creates an abrasion resistant layer on the knife and has a higher resistance to abrasive wear and, therefore, a longer life. After chipping, the degree of knife wear was assessed using a gravimetric method and 3D scanning analysis. Microstructural and surface characterisation revealed that cracking and abrasive wear were the main causes of tool blunting. The maximum removal of material on the cutting edge was 240 µm, the average weight loss of 0.58 g. In relation to wear, wood fragments remained on the cutting knife. Infrared spectroscopy of wood fragments showed changes in the chemical composition due to the high temperatures in the blade of the knife, and elemental analysis, the higher content of Al, Cr, and N elements in the wood fragments, probably due to the presence of particles from the coating of the knives. Microscopic analysis of the chips revealed the presence of metal particles from the knives on the structural wood elements. [ABSTRACT FROM AUTHOR]

This research deals with the processing of wood using a circular saw, which is associated with several risks and factors that affect the wood-splitting process. One of them is the wear of the teeth of the saw blade that change the magnitude of the cutting forces. The aim of this study is to compare real measured values and theoretical values when processing Norway spruce wood using two types of saw blades, i.e., sintered carbide (SC) and high-speed steel (HSS), with a diameter of 600 mm and 54 and 56 teeth, respectively. Experimental measurements were carried out on a special test device with the possibility of moving the tested wood into the cutting devices and a simple saw blade replacement system. The results of the contributions show significant differences, based on defined factors which represent the cutting and feed speed, which are supported by FEM analysis of cutting forces in the process of cutting wood—when changing the design of the saw blade. The results of the experiment show that the cutting conditions (cutting speed and feed speed) do not have a significant effect on the size of the cutting forces. The theoretical and real stress values for HSS discs ranged from 14 to 22 MPa. Significantly larger differences were recorded for discs with SC, where the real values of the maximum stresses were around 14 MPa and the theoretical ones around 25 MPa. When cutting spruce with a disc with SC slices, the maximum values of the theoretical cutting forces were in the range of 76 to 94 N and the maximum values of the measured cutting forces were in the range of 40 to 44 N. [ABSTRACT FROM AUTHOR]

Oak wood is characterized by high durability and resistance to changing weather conditions, it is a heavy, hard material (Brinell hardness class II), easily splitting, elastic. As a material, oak wood is easy process mechanically. Due to the above, oak wood is a valuable raw material with a wide range of applications in construction, including water construction. The research material was the oak obtained from the lock of the Czaniec Dam. The dam was built in 1958, it was also the same year the studied oak elements of the dam lock were built. The tested material was used in extremely variable environmental conditions until 2020 (temporarily completely submerged with water and outside the aquatic environment). The study carried out bending tests and compressive strength tests using the Shimadzu model AG-XV testing machine and chemical properties through elementary tests performed with the LECO CHN628 + S analyzer and thermogravimetric on the TGA/DSC3 apparatus from Mettler Toledo. The average density of the tested raw material in the absolutely dry state was 639 kg/m3, calorific value 18.39 MJ/Kg, cellulose content 43% hemicellulose 21%, lignin content 29% H2O 6% resins and ash 1%. The tested wood showed bending resistance of 76 MPA and compressive strength of 60.77 MPA along the fibres. The wood meets the required standards for structural wood ISO PN-EN 338:2016-06 class D40. Despite the difficult conditions and the long period in which the tested raw material has been kept, it reveals properties similar to those of medium fresh oak wood. [ABSTRACT FROM AUTHOR]

Spruce wood, after pine wood, is the main building material used in Europe. Many wooden buildings from the past eras were protected with simple means based on wood tar, vegetable oils and lime. In the Beskidy Mountains, in the works securing wooden objects, vegetable oil definitely prevailed, and later overworked engine oil prevailed. Due to the presence of carcinogenic compounds in the burnt engine oil, the wood obtained during the renovation works or demolition had to be disposed of. The share of post-consumer wood impregnated in Poland is about 3.1 million Mg per year, half of which comes from construction sites. The research covered about one hundred-year-old waste from the utility facilities located in Żywiec Area. The burnt oil emits harmful compounds; hence it belongs to the group of hazardous waste. The research was carried out in order to determine the possibility to use safely the discussed post-consumer wood waste. The bending and compressive strength of wood tests using the Shimadzu model AG-XV testing machine and chemical properties through elementary tests performed with the LECO CHN628 + S analyser and thermogravimetric on the TGA/DSC3 apparatus from Mettler Toledo were carried out. The tested wastes were characterized by a calorific value Q net dry 18.8 MJ / kg the average lignin content of the tested material was 32.8%, cellulose 53.5%, hemicellulose 7.6% and the ash content did not exceed 1%. The density of the tested raw material in the dry state ranged from 372 to 421 kg/m3. The tested wood showed an average bending strength of 49.8 MPA and 39.5 MPA for compression along the wood fibre. The tested wood met the standards of structural wood ISO PN-EN 338:2016-06 class C27. [ABSTRACT FROM AUTHOR]