A Method of Adding Binder by High-Pressure Spraying to Improve the Biomass Densification

Parametric studies on energy utilization of the Chinese medicine residues: Preparation and properties of densified pellet

The depletion of fossil fuels has fueled an increased interest in biomass resources usage for heat and electricity generation. As an important biomass resource, Chinese medicine residues have great potential in substituting fossil fuels. However, that is basically limited by its poor properties, including low bulk density, high moisture content, and inhomogeneous structure. Herein, a safe and sustainable strategy was reported to prepare a high-quality densified pellet derived from Chinese medicine residues to address these worries. In this process, mixed and simple size materials were densified under various moisture content and pressure using a laboratory electronic tablet press machine equipped a single pellet mold. Results showed that higher pressure, ideal moisture content (∼6.5 %), and mixed particle size could densify better quality pellets. These findings pave the way for the safely and efficient resource utilization of Chinese medicine residues, as well as providing theoretical guidance and technical support for the household heating.

Co-densification of rice straw and cow dung in different food-to-microorganism ratios for biogas production

Agricultural residues such as rice straw (RS) are desirable raw materials for biogas generation. However, the recalcitrant nature of RS hinders biogas production, and its low bulk density increases storage space requirements, transportation needs, and overall costs. These challenges could be resolved by pretreatment and pelletization. In this study, various thermal pretreatments were performed, and the best conditions (temperature and time) were identified. Also, rice straw and cow dung pellets (RCP) at different food-to-microorganism (F/M) ratios (0.5-2.5) were prepared. Parameters such as bulk density, moisture absorption, and drop shatter tests were conducted to evaluate the physical properties. Finally, the biochemical methane potential (BMP) study of the best RCP with varying total solids (TS: 4-12%) content was investigated. The results indicate that hot air oven pretreatment (for 60 min at 120 °C) resulted in maximum solubilization. In physical characteristics, RCP with an F/M ratio of 2.5 pellets was ideal. The bulk density of RCP 2.5 was found to be around 25 times that of the raw. Also, the TS 8% yielded maximum biomethane (279 mL/g-VSconsumed) as compared to other TS contents. Overall, this study will propel the growth of bioenergy while simultaneously tackling the pressing issues related to RS management.

Agricultural wastes co-densification: A solution for seasonal feedstock storage and anaerobic digestion performance improvement

Rice straw and pig manure pellets (RPP) and sorghum straw and pig manure pellets (SPP) were used to identify their competition as the flexible feedstock of anaerobic digestion with one-year indoor storage. The results indicated the effect of time on their characteristic was tiny during storage period, such as density, calorific value, total solid, volatile solid, ratio of carbon and nitrogen, and lignocellulosic components. Biogas yields of stored RPP and SPP were 8.8% and 26.7% lower than that of fresh pig manure (PM), and 45.4% and 56.1% higher than the sum of corresponding straw and PM digestion alone, respectively. Improvements in biodegradability were observed in co-densified biomass anaerobic digestion. Net biogas yield of RPP was 24.2% higher than that of rice straw, considering volatile matter loss and biogas yield decline during densification and storage stage. Priority of manure and supplement of co-densified biomass were proposed for feedstock supply on demand.