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High Yielding Tropical Energy Crops for Bioenergy Production: Effects of Crop Maturity, Plant Components, Harvest Years and Locations on Biomass Composition and Subsequent Biogas Yield.

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Title:High Yielding Tropical Energy Crops for Bioenergy Production: Effects of Crop Maturity, Plant Components, Harvest Years and Locations on Biomass Composition and Subsequent Biogas Yield.
Authors:K.C., Surendra
Contributors:Molecular Biosciences & Bioeng (department)
Keywords:Energy crops
biomass composition
bioenergy
anaerobic digestion
biogas
Date Issued:Aug 2017
Publisher:University of Hawaiʻi at Mānoa
Abstract:Bioenergy and biobased products generation from C4 perennial lignocellulosic feedstocks have attracted significant research interest due to their relatively high biomass yield at low agricultural inputs. However, biomass yield and composition of lignocellulosic energy crops vary with the species, crop maturity, crop components, and agro-climatic conditions. Such variation in the composition of the feedstock is believed to have a significant effect on the conversion process as well as on the yield and quality of the end products.
Thus, this study examined the compositional changes of Napier grass (Pennisetum purpureum) with respect to maturity (2, 4, 6, and 8 months age), and its effect on anaerobic digestion under three different biomass size regimes (6, 10, and 20 mm). This study also investigated the composition of different components (stems and leaves) of two energy crops [Energycane (Saccharum hybrids) and Napier grass] collected across the three locations and three years, and their effects on anaerobic digestibility.
Significant changes in plant composition were observed with crop maturity. The methane yields were higher for the biomass harvested at younger stages of maturity. For all ages, feedstock passed through a 6-mm sieve resulted in significantly higher methane yields compared to biomass passed through 10 and 20 mm sieves. Additionally, fiber digestibility was highest for the 2-month old harvest biomass and was lowest for the 8-month old harvest biomass.
Higher fiber content was found in the leaves of Energycane than stems, but the fiber content was higher in stems than leaves of Napier grass. Furthermore, the top leaves
and top stems of the Energycane resulted in higher specific methane yield compared to the bottom stems and bottom leaves. In Napier grass, however, specific methane yield was higher from leaves than stems. Between the crop types, for all locations and harvest years, fiber content was higher in Napier grass than Energycane. For all locations, Energycane had higher specific methane yield than Napier grass.
Depending on crop maturity, crop type, and plant components, energy crops differ significantly in composition and in specific methane yield, and require either different pretreatment conditions or conversion technologies for effective utilization of complete biomass.
Description:Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017.
URI:http://hdl.handle.net/10125/62557
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Ph.D. - Molecular Biosciences and Bioengineering


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