Volume: 5, 2026
5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: T018
DOI: https://doi.org/10.24326/ICDSUPL5.T018
Published online: 22 April 2026
Evaluation of pelleting of herbal biomass with the addition of kaolin and urea solution
Małgorzata Dula*1, Artur Kraszkiewicz 2
1 University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland
2 Department of Machine Operation and Production Processes Management, University of Life Sciences in Lublin, Głeboka 28, 20-612 Lublin, Poland
* Corresponding author: malgorzata.dula@up.edu.pl
The article presents a study utilizing by-products from the cleaning of perennial ryegrass (Lolium perenne L.) and chamomile (Matricaria chamomilla), both in pure form and in mixtures with kaolin and a urea solution. Basic physical and chemical parameters, as well as the energy consumption and efficiency of the pelleting process, were determined for the plant raw materials used. After appropriate preparation, the selected starting materials were subjected to pelleting. Regarding chemical characteristics, chamomile biomass exhibited superior energy properties due to higher carbon and hydrogen content and a higher heat of combustion, alongside lower levels of sulfur, volatile matter, and ash. Nitrogen content was comparable between the ryegrass and chamomile biomass. Significant variation was observed in the physical properties of the collected raw materials. Chamomile biomass exhibited the lowest bulk density (113.4 ± 5 kg·m⁻³), whereas ryegrass biomass showed a value approximately 50% higher (169.4 ± 3 kg·m⁻³). Similar trends were observed for tapped density; the mean values were 144.6 ± 5 kg·m⁻³ and 212.2 ± 4 kg·m⁻³, respectively, exceeding the bulk density by approximately 25–26%. Particle size distributions were found to depend on the type of raw material and its susceptibility to size reduction. Regarding the ryegrass cleaning residues, over 70% of the biomass was retained on the 1.4 mm and 1.0 mm sieves. In contrast, the chamomile biomass showed a share of just under 27% on these sieves, with the vast majority—over 70%—accumulating on the 0.5 mm, 0.25 mm, and 0.0 mm sieves. The produced pellets exhibited varying bulk densities and mechanical durability. Pellets produced with the addition of kaolin showed the lowest bulk density (763–875 kg/m³), whereas pellets made without additives or with a urea solution showed slightly higher values for this parameter (1022–1120 kg/m³). Increasing the moisture content of the raw materials from 16% to 20% resulted in a deterioration of the agglomerate’s properties regarding most analyzed characteristics, which to some extent contributed to reducing the process’s energy consumption. Adding 5% kaolin to the analyzed raw materials led to a decrease in agglomerate density and mechanical durability and an increase in ash content, but it reduced the process’s energy consumption by approximately 50%.
Keywords: formed biofuels, green ryegrass, chamomile
How to cite
Dula M., Kraszkiewicz A., 2026. Evaluation of pelleting of herbal biomass with the addition of kaolin and urea solution. In: 5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL5.T018