Tomáš Najser

Mr. Tomáš Najser

ENET, VŠB-TUO, Ostrava, Moravskoslezský Kraj, Czech Republic
orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 May 2022 in Materials
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Journal Article
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TNTomáš Najser
Tomáš Najser
BGBłażej Piotr Gaze
Błażej Piotr Gaze
BKBernard Knutel
Bernard Knutel
AVAdam Verner
Adam Verner
JNJan Najser
Jan Najser
ONOndřej Němček
Ondřej Němček
This paper presents the research results of the effect of using calcium oxide and potassium permanganate on the combustion of pellets from wheat bran and beet pulp. The measurements were performed in the technical laboratory of the Centre of Energy Utilization of Non-Traditional Energy Sources in Ostrava. The research examined the effect of the use of chemical substances on the amount of air pollutants from biomass thermal conversion in a low-power boiler and the process temperature. First, we performed technical and elementary analyses of agricultural waste. The raw material was then comminuted, mixed with a selected additive, pelletized, and finally burned in a low-power boiler. The additive was added in three proportions: 1:20, 1:10, and 1:6.67 (i.e., 15%) relative to the fuel weight. The combustion process efficiency was measured using a flue gas analyzer and three thermocouples attached to the data recorder. From the measurement results, we were able to determine the percentage reduction of pollutant emissions into the atmosphere (CO, NOx, and SO2) due to the use of additives. Because emission standards are becoming increasingly stringent and fuel and energy prices are rising, the results presented in this article may be useful to agri-food processing plants that want to manage these materials thermally.

7 February 2022 in Materials
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Journal Article
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JCJerzy Florian Chojnacki
Jerzy Florian Chojnacki
JKJan Kielar
Jan Kielar
Leon KukiełkaLeon Kukiełka
Leon Kukiełka
TNTomáš Najser
Tomáš Najser
APAleksandra Pachuta
Aleksandra Pachuta
VPVaclav Peer
Vaclav Peer
Granulated beet pulp and wheat straw, first separately and then mixed in a weight ratio of 50/50%, underwent a pyrolysis process in a laboratory batch generator with process temperatures of 400 and 500 °C. The feedstock’s chemical composition and the pyrolysis products’ chemical composition (biochar and pyrolysis gas) were analysed. A synergistic effect was observed in the co-pyrolysis of the combined feedstock, which occurred as an increase the content of the arising gas in relation to the total weight of the products. and as a reduction of bio-oil content. The maximum gas proportion was 21.8% at 500 °C and the minimum between 12.6% and 18.4% for the pyrolysis of individual substrates at 400 °C. The proportions of the gases, including CO, CO2, CH4, H2, and O2, present in the resulting synthesis gases were also analysed. The usage of a higher pyrolysis final temperature strongly affected the increase of the CH4 and H2 concentration and the decrease of CO2 and CO concentration in the pyrolysis gas. The highest percentage of hydrogen in the synthesis gas, around 33%vol, occurred at 500 °C during co-pyrolysis.

3 November 2022 in Materials
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Journal Article
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JCJerzy Florian Chojnacki
Jerzy Florian Chojnacki
JKJan Kielar
Jan Kielar
WKWaldemar Kuczyński
Waldemar Kuczyński
TNTomáš Najser
Tomáš Najser
Leon KukiełkaLeon Kukiełka
Leon Kukiełka
BGBłażej Piotr Gaze
Błażej Piotr Gaze
A comparative study was carried out of emissions from the catalytic combustion of pellets made from furniture board waste and pellets made from wood mixed with Fe2O3. The mass content of the Fe2O3 catalyst in the fuel was varied from 0% to 5%, 10%, and 15% in relation to the total dry mass weight of the pellets. The average flame temperature in the boiler was between 730 and 800 °C. The effect of the catalyst concentration in the fuel was analysed with respect to the contents of O2, CO2, CO, H2, and NOx in the flue gas and the combustion quality of the pellets in the heating boiler. Changes in the CO2 content and the proportion of unburned combustible components in the combustion residue were assessed. It was established that an increase in the Fe2O3 content of the prepared fuels had a positive effect on reducing NOx, CO, and H2 emissions. However, the proportion of iron oxide in the tested fuel pellets did not significantly influence changes in their combustion quality. A strong effect of the addition of Fe2O3 on the reduction of the average NOx content in the flue gas occurred with the combustion of furniture board fuel, from 51.4 ppm at 0% Fe2O3 to 7.7 ppm for an additive content of 15%. Based on the analysis of the residue in the boiler ash pan, the amount of unburned combustibles relative to their input amounts was found to be 0.09–0.22% for wood pellets and 0.50–0.31% for furniture board waste pellets.

9 August 2023 in Agriculture
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Journal Article
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APAleksandra Pachuta
Aleksandra Pachuta
BBBogusława Berner
Bogusława Berner
JCJerzy Florian Chojnacki
Jerzy Florian Chojnacki
GMGerhard Moitzi
Gerhard Moitzi
Jiří DvořákJiří Dvořák
Jiří Dvořák
MMMarcel Mikeska
Marcel Mikeska
The study aimed to assess the quality of spraying of ornamental conifer using a multi-rotor drone. We examined how the speed of drone movement and the propellers’ spin speed can affect the deposition quality of the sprayed liquid in the crown of blue spruce (Picea pungens Engelm.). Due to the avoidance in the future of droplet drift by air movements, an air injector atomiser for liquid spraying was used, and a low altitude of 0.6 m of the drone flying above the tree was used in the study. The drone moved at two speeds: 0.57 m·s–1 and 0.94 m·s–1. The propellers’ spin speeds were adjusted based on the drone’s weight with the spray liquid tank filled and empty. The propellers’ zero-spin rate was also included to compare the drone to a field sprayer. The tests were conducted in a laboratory setting. Volume and uniformity of liquid volume settled on the levels of samplers positioned on a tripod within the tree canopy were assessed. The samplers were placed in two zones of the tree: near the tree trunk and at a distance of 0.21 m from the trunk. Airstream speed generated by drone propellers was also evaluated inside the tree. The findings indicated that the rotations of propellers and air speed significantly influenced the quality of liquid deposition on samplers located away from the trunk. The results also showed that using a drone instead of a field sprayer could benefit the quality of the spray application. The weight of the multi-rotor drone, determined by the spray liquid tank’s filling level, can significantly impact the quality of spray deposition in the tree. Based on the investigations, it can be recommended that low-altitude spraying drones be adopted for studies and future strategies in precision agriculture using autonomous inspection-spraying drones.

5 November 2024 in Sustainability
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Andrzej PoltorakAndrzej Poltorak
Andrzej Poltorak
AOAnna Onopiuk
Anna Onopiuk
JKJan Kielar
Jan Kielar
JCJerzy Florian Chojnacki
Jerzy Florian Chojnacki
TNTomáš Najser
Tomáš Najser
BBBogusława Berner
Bogusława Berner
Using agricultural waste biomass pyrolysis to produce energy sources and biochar may support local economies in rural areas and enhance sustainability in the agricultural sector, reducing dependence on traditional energy sources and fertilisers. To obtain liquid and gaseous forms of biomass fuel, wheat straw pellets were pyrolysed in a screw reactor at temperatures of 300, 400, 500, 600, and 700 °C. An analysis was conducted to assess the influence of process temperature on the physicochemical composition of the raw material and the resulting biochar, pyrolysis liquid, and synthesis gas. The presence of potentially harmful substances in the biochar, whose addition to soil can improve soil properties, was assessed by quantitatively determining polycyclic aromatic hydrocarbons (PAHs). Similar tests were carried out for pyrolysis fluid. The assessments were based on the standards for the most dangerous PAHs: fluorene, anthracene, fluoranthene, benzo[b]fluorine, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene. The results indicated that the total content of polycyclic aromatic hydrocarbons in the biochar ranged from 346.81 µg·kg−1 at 300 °C to 1660.87 µg·kg−1 (700 °C). In the pyrolytic fluid, the PAH content ranged from 58,240.7 µg·kg−1 (300 °C) to 101,889.0 µg·kg−1 (600 °C). It was found that the increase in PAH content in both the biochar and the liquid progressed with increasing pyrolysis temperature. After finding a correlation between the increase in the PAH content in biochar and the increase in the content of high-energy gases in the synthesis gas, it was concluded that it is difficult to reconcile the production of PAH-free biochar in the pyrolysis of biomass with obtaining high-energy gas and pyrolysis oil.

24 August 2024 in Agronomy
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Journal Article
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BBBogusława Berner
Bogusława Berner
JCJerzy Florian Chojnacki
Jerzy Florian Chojnacki
Jiří DvořákJiří Dvořák
Jiří Dvořák
APAleksandra Pachuta
Aleksandra Pachuta
JNJan Najser
Jan Najser
MMMarcel Mikeska
Marcel Mikeska
On a mounted laboratory stand, comparative tests were carried out on the effectiveness of spraying wheat plants with liquid using a multi-rotor drone. The study was undertaken with and without propeller rotations. The lack of rotations simulated spraying by a ground sprayer. The height of the drone’s displacement above the plants was similar to that of the nozzles above the plants used when spraying with field sprayers, 0.5 m and 1.0 m. The speed of the drone movement was 0.57 and 1.0 m·s−1. The effects of the height and speed of the drone’s movement and the impact of the airflow on the volume and uniformity of the liquid application on the plants were assessed. In addition, changes in the transverse distribution of liquid volume in the droplet stream and the transverse distribution of the air velocity in its stream were evaluated. The liquid was sprayed at a constant pressure of 0.2 MPa. The study’s results show that the low height of the drone displacement not only had a strong effect on increasing the liquid volume applied to the plants but also improved the uniformity of application at plant levels. It was also noticed that, at a height of 0.5 m, there was a significant irregularity in the air stream under the drone.