Grindelia squarrosa: A Potential Arid Lands Biofuel Plant

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• 作者：Bishnu P. Neupane ; David Shintani ; Hongfei Lin ; Charles J. Coronella ; Glenn C. Miller
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2017
• 出版时间：January 3, 2017
• 年：2017
• 卷：5
• 期：1
• 页码：995-1001
• 全文大小：483K
• ISSN：2168-0485

文摘

Gumweed (Grindelia squarrosa) has potential as a biofuel/biomaterial crop in arid lands. Two years of biomass production data at University of Nevada, Reno (UNR) field plots varied from 6700 kg/ha up to 14 900 kg/ha with an average of 9950 kg/ha. Gumweed was planted in 4 m × 4 m plots at spacings of 15, 20, 25, 30, and 37 cm with three replications each. Acetone extraction of the ground, dried biomass yielded about 12.5% extractable hydrocarbons, called biocrude or crude resin. Approximately 52% of the biocrude extract consists of the C₂₀ diterpene acid grindelic acid, which is also approximately 6.5% of the dried plant biomass. Additional carboxylic acids bring the total carboxylic acid fraction to approximately 68% of the biocrude. Also found in the biocrude is approximately 4.7% monoterpenes, including pinene, limonene, germacrene, elemene, and camphene. Acid-catalyzed methylation of the biocrude followed by hexane extraction and removal of the hexane and remaining methanol produced an approximately 72.5% yield of biofuel materials from the original extract. This mixture contained the methyl esters of the carboxylic acids, terpenes, and other unidentified compounds. When mixed with diesel fuel up to 20%, this blend produced a biofuel that met biofuel standards, although viscosity issues limit the percentage of gumweed biocrude that can be used in the blend. Grindelic acid methyl ester and a second ester produced during the acid-catalyzed methylation reaction (also identified as grindelic acid by GC–MS) eluted toward the end of a diesel fuel chromatogram. The Grindelia biofuel materials can be produced up to 1290 L/ha on a biennial basis, which is equivalent to 138 gal/acre, when extracted in hexane. This potential fuel can be produced on the arid lands of Nevada with minimal inputs of water, nutrients, and other agricultural services.