Arkadiusz Gendek

Comparison of heat of combustion and calorific value of the cones and wood of selected forest trees species

Abstract Every year, scaling plants buy (up to tens of tons) cones which needs to be peeled. After the process of scaling, the cones themselves are waste, which is partly sold. The problem of waste disposal is especially severe in plants where the processing is performed by electrically-powered scaling cabinets, but the problem does not apply to facilities where pellets are burned to produce beat. We examined the beat of combustion and calorific value of the residues from scaling plants that can be used in the production of refined wood fuels. The residues consist of the empty cones of pine, spruce, larch as well as husks and stems of silver fir. Additionally, we conducted measurements of the beat of combustion for wood and cones of each species and compared them to their respective calorific values. The results revealed that the average calorific value of the cones is in the range 17.81-19.86 MJ/kg. Our work showed that empty cones have a significantly higher calorific value and beat of combustion than the wood of spruce, larch and fir. In the case of pine, cones and wood did not differ significantly. These results led us to the conclusions that empty de-scaled cones can be utilised as a valuable primary solid fuel or fuel additive for the production of refined products for the local market. Due to the low annual production of cones in comparison to other materials such as sawdust and wood chips, pine cones should be used as a supplement, to enrich fuels of inferior quality by enhancing their energetic properties.

Noise assessment for selected seed extraction plants

Noise assessment for selected seed extraction plants. In the process of seed extraction, extraction plant staff is exposed to work in onerous conditions due to noise. The article outlines the results of noise measurements in the cone extraction hall and offi ce rooms within the extraction plant operating in the Czarna Białostocka and Grotniki forest districts. The measurements were carried out in accordance with standard PN-EN ISO 11201:1999, at work stations, while the extraction cabinets, separators and thresher riddle were in use for the purpose of seed extraction and processing. The results obtained were confronted with the applicable standards and provisions concerning admissible noise levels at work stations. The average noise value (LAeq,T) in the production hall equalled 83.7 ±2.0 dB(A) in Czarna Białostocka and 81.2 ±1.4 dB(A) in Grotniki. In both extraction plants, these values should be considered onerous for the employees and the risk due to exposure to noise should be considered moderate. The most signifi cant source of noise emission in the Czarna Białostocka seed extraction plant is the mechanical seed thresher riddle, while in Grotniki, the biggest noise was produced by the extractor matched with the thresher riddle. The respective values of 55.9 ±0.2 and 42.5 ±0.9 dB(A) were obtained in the offi ce rooms immediately adjacent to the seed extraction hall. According to these values, the risk of exposure to noise in offi ce rooms within the plant is low.

Variability of energy woodchips and their economic effects

Abstract The main aim of the work is to assess physical parameters of forest woodchips and their impact on the prices achieved by the supplier in transactions with a power plant. During fragmentation of logging residue, high content of green matter and contaminants negatively impacts the quality parameters that serve as basis for settlements. The analysis concerns data on the main parameters - water content, fuel value, sulphur and ash content - from 252 days of deliveries of forest chips to a power plant. The deliveries were realised from forested areas on an average about 340 km from the plant. Average water content and the resultant fuel value of forest chips was within 27-47% and 8.7-12.9 GJ×Mg-1 (appropriately), respectively. They depend on the month in which they are delivered to the power plant. The threshold values for the above-mentioned parameters are set by the plant at a real level and the suppliers have no problems with meeting them. The parameter that is most frequently exceeded is ash content (11.5% of cases). The settlement system does not differentiate on the basis of the transport distance but gives possibility to lower the settlement price when the quality parameters are not met but provides no reward for deliveries with parameters better than the average ones. On the basis of results obtained, it was calculated that average annual settlement price is lower than the contract price by about 0.20 PLN×GJ-1, which in case of the analysed company may translate into an average daily loss of about 700 PLN.

Variability of silver fir (Abies alba Mill.) cones – variability structure of scale surface area

Abstract This study was conducted on a batch of closed silver fir cones from Jawor Forest District and a mixture of scales from the seed extraction facility Grotniki. The scales were divided into three size classes corresponding to the bottom, middle and upper part of the cones and their area was measured with the Multi Scan Base v.18.03 software. Based on the sum of the inner and outer surface area of all scales, we then determined the total area of evaporation from the cones. In addition, the area of protruding scales was measured for differently sized scales from different parts of the cones. Previous studies have shown that the average outer surface of a closed cone, calculated as the sum of protruding scales, accounts for 10% of the outer surface of an open cone. Pictures of both scale surfaces with the internal seed bed and the external protrusions were taken using a scanning electron microscope. We noticed significant differences in dimension and shape of the channels and trichomes on the scale surface. On the inner side of the scales, we found a high diversity of trichomes of different lengths, whilst the outer side contained channels. Presumably, these characteristics affect the rate of water loss from the cones during desiccation and separation of the seed. In-depth knowledge on the evaporative surfaces of fir cones and scale structure will be helpful for optimizing the industrial processes of seed extraction.

Variability of cones and scale surface area of European larch (Larix decidua Mill.)

Abstract The article describes the shape of the cones of the european larch (Larix decidua Mill.) using the fourth degree polynomial fitting function. The material is from the seed orchard of the Barycz Forest District. The curves were used to calculate the area and volume of single cones. it was not possible to generalize the formulas to calculate the surface and volume of larch cones using the described method, due to the large variability of the empirical coefficients of the equations. Finally, to calculate the area and volume of the cones, the formula to determine the solid figure of a cone was used. A constant αs of 0.43 was introduced to the formula. Calculated volume values were compared to actual volumes measured with a water-filled burette. The mean surface area of the larch cones was calculated from the forming function and was 780 mm2, and the volume was 2434 mm3. the values calculated from the cone formulas after taking into account the αs and constants (0.68 and 0.53) were 783 mm2 and 2415 mm3, respectively. the outer and inner surfaces of the seed scales located in the central part of the larch cones were photographed using a Quanta 200 scanning microscope. Specific features of the scales were measured using the Multi Scan Base program. We found that the outer and inner surfaces of the larch scales, as with pine and fir, differed. On the outer side, scales are formed by thick-walled cells with visible, protruding trichomes. thin-walled cells with jagged cell walls are visible on the inside at the location of the wings and seeds. long stem cells, resembling threads, were observed on the surface of the scales, which are absent on pine and fir seed scales.