Evaluation of Invasive Herbaceous Plants Utilization for the Production of Pressed Biofuel

The present article focuses on pressed biofuel preparation from invasive herbaceous plants, and the quality indicators and properties were analyzed and determined. Two invasive herbaceous plants were chosen for this research: giant knotweed (Fallopia sachalinensis) and Sosnowsky's hogweed (Heracleum sosnowskyi). For a control, pine wood biomass was utilized. After harvesting and drying, plant biomass was chopped and milled and later pressed into cylindrical pellets and briquettes. The research results for the pellets' and briquettes' physical and elemental properties showed that the density of the pellets (moisture 5-8%) reached 1145.60-1227.47 kg m-3, and the average density of the briquettes reached 615.60-867.31 kg m-3. The determined critical compressive strength of the pellets ranged from 420 N to 676 N, and the briquettes disintegrated under a significantly greater critical force of 783 N to 1219 N. The variation in pellet compressive strength with changes in their moisture content was also investigated. The determined lower caloric value of the pellets varied from 15.9 MJ kg-1 to 18.6 MJ kg-1. Harmful gas emissions during burning of the tested biofuel pellets were also evaluated and determined, and they were sufficiently low and did not exceed the permissible values. Finally, it can be stated that all of the pressed biofuels produced from invasive herbaceous plants met the most important requirements for the quality of pressed solid biofuel and can be used for burning in special boilers.