Kinetics of acid hydrolysis of the pretreatment liquor obtained by hydrothermal pretreatment

Author(s)

Pedro Yoritomo Souza Nakasu

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2015-07-30

Examining board members

Aline Carvalho da Costa; Jose Geraldo da Cruz Pradella; Vera Lucia Reis de Gouveia

• Advisor: Aline Carvalho da Costa; Sarita Cândida Rabelo

Abstract

In the context of second generation ethanol production from sugarcane bagasse, pretreatment is practically compulsory in order to depolimerize the carbohydrates (cellulose and hemicelluloses) via chemicals or enzymes. Hydrothermal pretreatment ¿ considered promising for using a "green" ¿ solubilizes about 65% of the hemicelluloses in sugarcane bagasse. Hemicelluloses hydrolysis during pretreatment is not complete; nearly 70% of the xylose recovery from the pretreatment liquor is present in oligomeric form which cannot be directly metabolized to ethanol by microrganisms. Therefore, it is necessary to perform a post-hydrolysis step of the hemicellulosic hydrolysate for total pentose use via fermentation. A '2 POT. 3' full factorial design with temperature and acid loading as factors set up a kinetic study of the post-hydrolysis process with sulfuric, oxalic and maleic acids. Using a 2,0 L Parr reactor, a scale never employed before for similar studies, allowed one to verify problems related to mass and energy transfer in the system, like the lignin precipitation. Xylose and furfural post-hydrolysis profiles showed the reaction time in which xylose peaked with minimum furfural production. Among the three studied acids, sulfuric acid showed the fastest kinetics of post-hydrolysis with full hydrolysis of xylooligomers in less than an hour of reaction time. ...Note: The complete abstract is available with the full electronic document (AU)

• FAPESP's process: 13/05369-2 - Kinetics of acid hydrolysis of the liquid stream of hydrothermal Pretreament
• Grantee: Pedro Yoritomo Souza Nakasu
• Support Opportunities: Scholarships in Brazil - Master