Fast and Simple Measurement of Energy Requirements for Plant Stalk Cutting

摘要

Size reduction/cutting/grinding of lignocellulosic feedstocks is a critical operation for various downstream biomass utilization processes. Energy expended in cutting biomass is fundamental data for the design of size reduction machinery. Measurementof biomass cutting energy involves expensive instrumentation such as a universal testing machine (UTM) or torque sensors with dedicated instrumentation. In this research, we developed a novel idea in which a digital torque wrench (DTW) in combination with a common bypass iopper was utilized to determine the cutting energy of wet corn stalks (70.89 ± 1.37% w.b.). One handle of the Iopper was synchronized with the DTW and the force was applied through the DTW. The standard method of energy measurement involves a UTM in combination with a modified Warner-Bratzler device (blade with sharp cutting edge). To ensure that similar input material was used for DTW and UTM measurements, the same corn stalk was utilized and cutting was carried out at marked adjacent locations. Mechanical measurements (peak torque - Nm, specific torque - MJ/m~2, peak stress -MPa, net energy- J, and specific energy - kJ/m~2) from these devices were determined and their correlations were utilized to develop prediction models. DTW peak torque and UTM standard net cutting energy (r > 0.95), and DTW specific torque and UTM specific energy (r > 0.98) were strongly correlated. Direct proportion simple linear models were developed including: Net cutting energy (J) =0.1621 x Peak torque (Nm) (R~2 = 0.9108) and Specific cutting energy (kJ/m~2) = 156.65 x Specific torque (MJ/m~2) (FC = 0.9775) These models were logical choices and exhibited comparable performance, even though linear models with an intercept had slightly higher R~2's. The random distribution of the residuals of models prediction further demonstrated their validity, The DTW cutting energy measurement method is fast, simple, less expensive than a UTM, portable, and suitable for onsite field measurements. This research indicates the potential for development of a portable instrument based on the DTW using dedicated electronics for measuring energy for cutting herbaceous plant material.