Filters
Evaluation of the Effects of Using the Giant Miscanthus (Miscanthus × Giganteus) Biomass in Various Energy Conversion Processes
The giant miscanthus (Miscanthus × giganteus) is one of the most essential energy plants. It also finds various alternative uses, including installing belts to prevent soil erosion. Biomass from such belts should be removed and rationally managed every year. The parameters of miscanthus biomass were investigated in terms of its suitability for combustion and anaerobic fermentation. Under the conditions of the experiment, miscanthus achieved a stable yield already in the second year of vegetation, mainly due to the high planting density. Energy parameters turned out to be typical for straw biomass (calorific value 18.06 MJ/kg). Relatively low ash melting temperatures (<1400 °C) and their chemical composition meant a high risk of contamination depositing on heating devices, which is often indicated as a shortcoming of biomass compared to hard coal. Miscanthus silage can be a valuable substrate for anaerobic digestion, but it requires a sufficiently early harvest, which affects the yield of biomass. The yield of energy in biomass obtained after drying plants was 163,623.6 MJ/ha. In contrast, the yield of energy from biomass collected in summer and processed into biomethane was much lower and amounted to 72,978.2 MJ/ha.
Energetic Potential of Tobacco Waste Within Combustion or Anaerobic Digestion
The growing demand for energy biomass encourages the use of waste and by-products from agriculture. The aim of this study was to assess the suitability of tobacco stalks (TSs) for energy use in the combustion and anaerobic digestion (AD) process, as well as the technical and environmental effects of energy production from this waste raw material. Laboratory tests were conducted on the energy parameters of TS biomass, the chemical composition of ash from its combustion, and the efficiency and composition of biogas generated during the AD process of TS silage with various silage additives. The tests were conducted in accordance with the standards applicable to biomass fuels. The energy yield and emission reduction obtained by the replacement of conventional energy sources were calculated. The energy parameters of TS were inferior compared to the raw materials most often burned in boilers (wood, straw). The high ash content (7.31% in dry mass) and its chemical composition may adversely affect heating devices. Methane yield from TS silage was lower (18.55–24.67 m3/Mg FM) than from silage from crops grown for biogas plants (i.e., 105 m3/Mg for maize silage). Silage additives improved TS silage quality and methane yield (from 18.55 to 21.71–24.67 m3 CH4/Mg in case of silages with additives. Energy yield and emission reduction were higher in the case of TS combustion, but AD is a process consistent with the circular economy. Both TS energy management processes are in line with the Sustainable Development Goals as they prevent the devaluation of agricultural waste, providing a valuable resource for bioenergy.