CLEAN FRACTIONATION OF BIOMASS - STEAM EXPLOSION AND EXTRACTION

Type of Document Master's Thesis
Author Ibrahim, Mazlan
Author's Email Address mibrahim@vt.edu
URN etd-2998-114756
Title CLEAN FRACTIONATION OF BIOMASS - STEAM EXPLOSION AND EXTRACTION
Degree Master of Science
Department Wood Science and Forest Products
Advisory Committee
Advisor Name Title
Wolfgang G. Glasser Committee Chair
Foster A. Agblevor Committee Member
Richard F. Helm Committee Member
Keywords

* Red oak (Quercus rubra)
* Oil palm (Elaeis guineensis)
* Hydrothermal process
* Cellulose
* Lignin
* Hemicelluloses
* Summative analysis.

Date of Defense 1998-02-24
Availability unrestricted
Abstract

The fractionation of two biomass resources, red oak (Quercus rubra) chips and oil palm

(Elaeis guineensis) trunk solids, into constitutive chemical components, cellulose,

hemicelluloses (called "other carbohydrates") and non-carbohydrates (includes lignin,

tannins, etc.), was studied quantitatively in terms of relative cleanness. Red oak chips

were steam exploded using a batch reactor at five different treatment severities, Ro 5,000,

10,000, 15,000, 20,000 and 35,000. Steam exploded fibers (SEF) of each severity were

extracted with water and alkali. Mass fractionation and summative analysis data of all

solid biomass fractions were determined. These data were interpreted in term of a

unifying clean fractionation concept designed to evaluate the effectiveness of the

fractionation processes. Within a series of severities applied to a single biomass resource,

the quantitative clean fractionation can be used to choose an optimum severity for the

isolation of any particular component fraction. The red oak results revealed that 25 % (on

average) of biomass solids were lost during steam explosion. Cellulose remained almost

unaffected (retained in fibers form) by water and alkali extraction. About 35-55 % of the

hemicelluloses can be recovered in the water extracted liquor fraction (WEL). The

remaining non-cellulosic carbohydrates were lost during steam explosion, especially at

high severity. At Ro 10,000 and above, alkali extracted fibers (AEF) consists almost

entirely of cellulose and non-carbohydrates. The majority of the non-carbohydrates

component (> 50 %) can be isolated by alkali extraction. The non-carbohydrate

component harvested increased with severity to 67 % at Ro 35,000.

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