Theses and Dissertations

Author

Qi Li

Issuing Body

Mississippi State University

Advisor

Steele, Philip H.

Committee Member

Ingram, Leonard L., Jr.

Committee Member

Hassan, El Barbary M.

Committee Member

Srinivasan, Radhakrishnan

Date of Degree

1-1-2012

Document Type

Dissertation - Open Access

Abstract

Levoglucosan is the major anhydrosugar component of bio-oil produced by fast pyrolysis. Previous research has shown that levoglucosan yield can be greatly increased if a mild acid pretreatment is applied to demineralize the feedstock prior to pyrolysis. The interest in levoglucosan production is that it provides a route to production of monomeric sugars, primarily glucose, which can be utilized to produce biochemically derived fuels (ethanol, butanol, etc.) In one study, four different lignocellulosic biomass were subjected to pyrolysis as feedstocks to produce bio-oils via fast pyrolysis in a 7 kg/h feed rate auger reactor. Feedstocks were pretreated with dilute phosphoric acid and bio-oils were produced and analyzed to compare the bio-oil characteristics from both untreated and treated feedstocks. The results shown in this study strongly indicate that the ash content and alkali metal content are very important parameters which can greatly affect the yield and many properties of bio-oils produced during fast pyrolysis. The dilute acid pretreatment performed in this study significantly reduced the total ash content and alkali metal content in the feedstocks, resulting in a great increase in the bio-oil and levoglucosan yields. It was also shown that dilute acid pretreatment was more effective in treating herbaceous feedstocks than woody biomass in terms of increasing bio-oil production yield and improving bio-oil properties. In one study, bio-oil composed of high levoglucosan concentration was produced via fast pyrolysis of dilute acid pretreated loblolly pine wood in an auger reactor. Water-to-bio-oil ratio, temperature, and time were selected as the three parameters to investigate the optimal condition for extracting the maximum amount of levoglucosan from the bio-oil. The optimal condition for levoglucosan extraction determined was 1.3 : 1 (water-to-bio-oil ratio), 25 oC, and 20 min, producing a levoglucosan yield of 12.7 wt %. The final study developed a new method based on pyrolysis of dilute acid pretreated loblolly pine wood and modification of the pyrolysis process. This new method resulted in a significant 30.7 wt % increase in levoglucosan concentration in the bio-oil organic portion. The results indicated that this method successfully suppressed the levoglucosan decomposition during fast pyrolysis.

URI

https://hdl.handle.net/11668/18874

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