Journal of Energy Bioscience 2025, Vol.16, No.3, 105-116 http://bioscipublisher.com/index.php/jeb 106 This study aims to gain a comprehensive understanding of the potential of rapeseed as a clean energy resource. We will introduce its planting characteristics, biomass types, common energy conversion methods (such as pressing, combustion and pyrolysis), and its positive impact on the environment and future application opportunities. We hope to clarify what role rapeseed can play in the global energy transition by organizing these research results and new applications. At the same time, we also analyze the challenges it currently faces and provide some references for future technological development and policy making. 2 Composition and Characteristics of Rapeseed Biomass 2.1 Primary components: stalks, leaves, pods, roots, and residual seeds After rapeseed is harvested, many plant parts are left, which can be used as biomass resources. They mainly include stems, leaves, pods (also known as pod shells), roots and some seeds that have not been fully harvested. Rapeseed straw is generally composed of stems and pod shells. The ratio of these two parts varies depending on the variety and planting method of rapeseed (Wassner et al., 2020). For example, sometimes the mass ratio of stems to pod shells is between 0.8 and 2.2. In addition to these, the remaining seeds and roots can also be used to develop biomass resources (Medvedev et al., 2020). 2.2 Biochemical profile: lignocellulosic content (cellulose, hemicellulose, lignin), moisture, ash, and calorific value Rapeseed is a lignocellulosic biomass, the main components of which are cellulose, hemicellulose and lignin. The stem has a high cellulose content and a high calorific value of about 17 to 18 MJ/kg, which makes it suitable for use as energy, and the ash content is relatively low, about 6% (Wassner et al., 2020). The composition of the husk is different from that of the stem. The cellulose and lignin content is relatively low, but the ash content is higher, generally between 5% and 14%. Therefore, the husk is more suitable for biochemical processing, such as extracting chemicals. When rapeseed biomass is broken down by enzymes, the composition of lignin and hemicellulose will affect the release of sugars. When the content of components such as G-type lignin, fucose, galactose, arabinose and rhamnose is low, it is more conducive to saccharification and ethanol production (Pei et al., 2016). Rapeseed contains a lot of crude protein and has a high energy value, about 13 MJ/kg, which is higher than the stem and leaf parts (about 9.6 MJ/kg) (Medvedev et al., 2020). In some energy conversion methods, such as pyrolysis or hydrothermal carbonization, the calorific value of rapeseed can be even higher, sometimes reaching 25 MJ/kg, and the water content is not high, making it suitable for energy (Vallejo et al., 2024; Wang et al., 2024). 2.3 Comparative analysis: how rapeseed compares with other common bioenergy crops like corn stover, miscanthus, and switchgrass Compared with several other common energy crops, such as corn stalks, miscanthus and switchgrass, rapeseed also has many advantages. In terms of calorific value: the calorific value of rapeseed stems is about 17 to 18 MJ/kg, which is similar to corn stalks, miscanthus and switchgrass. If processed, such as hydrothermal carbonization, the calorific value can be increased to 25 MJ/kg, even exceeding some herbaceous crops (Wassner et al., 2020; Vallejo et al., 2024). Ash content: The ash content of rapeseed stems is low, about 6%, which is conducive to direct combustion. The ash content of pods is higher, so be careful to separate them when using them (Wassner et al., 2020). In terms of composition: The ratio of lignin to cellulose in rapeseed is similar to that of corn straw. However, its hemicellulose monosaccharides and lignin types have a special effect on decomposition efficiency (Pei et al., 2016). In terms of yield: The yield of rapeseed straw is between 2 and 6 tons per hectare, which is comparable to crops such as corn. However, the yield will also be affected by the variety and planting method (Wassner et al., 2020). 3 Cultivation Practices and Biomass Yield Optimization 3.1 Agronomic practices: soil requirements, sowing methods, irrigation, and fertilization To grow rapeseed well, with high yield and good efficiency, we need to start from multiple aspects, such as soil, sowing methods, watering and fertilization. It is important to choose the right tillage method, such as
RkJQdWJsaXNoZXIy MjQ4ODYzNA==