Statistical prediction of biogas and methane yields during anaerobic digestion based on the composition of lignocellulosic biomass

Abstract

In the described study, the relationships between the percentage and structure of selected lignocellulosic components and the efficiency of their anaerobic digestion and the quality of the produced biogas were analyzed. This research included various lignocellulosic raw materials. The biogas efficiency and quality tests were carried out according to DIN standard 38 414-8 (1985) and VDI standard 4630 (2016). Multiple TAPPI standards and the Seifert method were used to determine the chemical composition of the lignocellulose materials. Lignin structure analysis was performed using Fourier transform infrared spectroscopy. Wide-angle X-Ray scattering analysis was used to determine the degree of crystallinity of cellulose. The biogas was positively correlated with C=O and the syringyl to guaiacyl ratio, and negatively correlated with the crystalline structure of cellulose, lignin, cellulose, and extractives. In addition, methane was positively correlated with holocellulose and extractives and negatively correlated with the crystalline structure of cellulose, cellulose, substances soluble in NaOH, and the OH groups. The found independent features accounted for 86.0% of the biogas variability and 68.0% of the methane variability.