Perennial grasses display several positive attributes as suitable energy crops for use as a solid fuel for direct combustion, such as high annual production of dry matter per unit area, perennity and high harvest flexibility. This study aimed to characterize the chemical composition and calorific value of 18 elephant grass (EG) varieties (Pennisetum purpureum Schum.) and 10 other potential bioenergy feedstocks intended for direct combustion. Samples were obtained from 6-month-old EG and sorghum and 3-year-old eucalyptus, Mimosa caesalpiniaefolia, and bamboo plants. Sugarcane bagasse and straw, rice husk, corn stover, coconut husk, and fiber samples were also evaluated. The elemental composition, lower heating value (LHV), and cellulose (CEL), hemicellulose (HCEL), lignin (LIG) and ash contents (% dry matter) were analyzed. The results indicated that the EG genotypes showed significant differences when compared with other evaluated biomasses, but showed no differences among themselves. The EG varieties showed a mean LHV (16.7 MJ/kg) superior to that of rice husk, sugarcane bagasse, and sorghum and similar to that of sugarcane straw, coconut fiber, and corn stover. The EG varieties showed a mean ash content (4.74%) inferior to that of rice husk, sugarcane bagasse, coconut fiber, and sorghum; a mean CEL content (36.0%) similar to that of sugarcane straw, coconut fiber, corn stover, sorghum, and Mimosa caesalpinifolia; HCEL; a mean HCEL content (30.3%) superior to that of rice husk, bamboo, eucalyptus, M. caesalpinifolia, coconut husk, and fiber; and a mean LIG content (8.80%) superior to that of corn stover and similar to that of sorghum, sugarcane bagasse, and straw biomass. The significant capacity of EG to accumulate dry matter was associated with the biomass quality attributes (LHV and CEL, HCEL, LIG, and ash contents), thereby making it an excellent alternative to lignocellulosic feedstock for direct combustion.

中文翻译：

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象草品种和其他用于直接燃烧的原料的化学成分和热值

多年生草作为适合用作直接燃烧的固体燃料的能源作物显示出几个积极的属性，例如单位面积干物质的年产量高、多年生性和收割灵活性高。本研究旨在表征 18 种象草 (EG) 品种 ( Pennisetum purpureum Schum.) 和其他 10 种用于直接燃烧的潜在生物能源原料的化学成分和热值。样品来自 6 个月大的 EG 和高粱以及 3 岁的桉树，含羞草, 和竹子植物。还评估了甘蔗渣和稻草、稻壳、玉米秸秆、椰子壳和纤维样品。分析了元素组成、低热值 (LHV) 和纤维素 (CEL)、半纤维素 (HCEL)、木质素 (LIG) 和灰分含量（% 干物质）。结果表明，EG 基因型与其他评估的生物量相比显示出显着差异，但它们之间没有差异。EG 品种的平均 LHV (16.7 MJ/kg) 优于稻壳、甘蔗渣和高粱，与甘蔗秸秆、椰子纤维和玉米秸秆相似。EG 品种的平均灰分含量（4.74%）低于稻壳、甘蔗渣、椰子纤维和高粱；平均 CEL 含量 (36.0%) 与甘蔗秸秆、椰子纤维、玉米秸秆、高粱相似，含羞草；HCEL; 平均 HCEL 含量 (30.3%) 优于稻壳、竹子、桉树、M. caesalpinifolia、椰子壳和纤维；平均 LIG 含量 (8.80%) 优于玉米秸秆，与高粱、甘蔗渣和秸秆生物量相似。EG 积累干物质的显着能力与生物质质量属性（LHV 和 CEL、HCEL、LIG 和灰分含量）有关，从而使其成为直接燃烧木质纤维素原料的绝佳替代品。