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Degree

Master of Science in Engineering, University of Akron, Chemical Engineering, 2011.

Abstract

A high pressure carbon dioxide- water pretreatment process was developed for guayule biomass. The guayule biomass was mixed with water and then loaded to a reactor where it was exposed to a biphasic environment consisting of a CO2-rich vapor phase and water-rich liquid phase.Then, the biomass was enzymatically hydrolyzed and the sugar content was measured at the end. One hundred and six (106) experimental runs were conductedin the temperature range of 145 °C to 210 °C and pressure range between 3.4 MPa to 34 MPa. The solid ratio (mass solids/mass water) was between 0.17 to 1.7. The packing was between 0.03 to 0.2 g biomass per cc of reactor and the holding time was between 20 to 840 minutes. Two reaction models were fit to the experimental data. Each model had four parameters and was fit to 106 data points, first order reactionmodel with an average absolute percent deviation(AAD%) of 22% and third order reaction model with AAD% of 18%.Then, the same process was implemented to a pilot scale vessel with a 1 liter volume and pressure release into a 6 liter closed vessel. Roughly 85% of total sugar yield was achieved at both the bench and pilot scales with optimal yield in the range of 200°C, 12 MPa, and 0.5 solid ratio. The effect of rapid pressure release (explosion) contributed up to 15% of total sugar release at the optimal condition. By-products of acetic acid, furfural, and hydroxymethylfuran comprised less than 1wt% in the hydrolysate, minimizing toxicity of the hydrolysate for further fermentation.

Subject Headings

Chemical Engineering

Keywords

Lignocellulosic biomass; Pretreatment; CO2 Pretreatment; Bioethanol

Committee / Advisors

Dr. J. Richard Elliott (Advisor)
Dr. Steven Chuang (Committee Member)
Dr. Lingyun Liu (Committee Member)

Pages

54p.

Document number: akron1313013654
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=akron1313013654

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