Hasbi PRIADI thesis defense

From Wednesday 06.26.2024 to Saturday 06.29.2024

Address:

at Universitats Indonesia

M Hasbi Priadi, from de DSEE department and GEPEA laboratory will present his research about :

"Experimental studies and modeling of hydrothermal fractionation of palm oil by-products for bioethanol production"

 

 

Thesis defense notice

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This research comprehensively investigates the modeling, simulation, and experimental aspects of hydrothermal fractionation for second-generation bioethanol production from palm oil by-products. The Analytic Hierarchy Process (AHP) is employed to select the most suitable types of palm oil waste as biomass feedstocks, utilizing pairwise comparisons to obtain the weight of importance in decision criteria and relative performance measures. The simulation component focuses on evaluating technical performances through process simulation with Aspen Plus™, conducting environmental impact assessment via a Life Cycle Assessment (LCA) framework, and performing economic analysis using the levelized cost approach. Complementing the simulation efforts, experimental studies are carried out to optimize subcritical water hydrolysis (SWH) conditions for maximizing reducing sugar yield from oil palm fronds, thereby enabling subsequent fermentation studies and exploration of inhibition phenomena impacting fermentation performance. Based on their availability, production cost, and yield potential, empty fruit bunches (EFB) are identified as the most promising options for lignocellulosic ethanol production. The technical performance results from the simulation reveal that the catalytic hydrothermal hydrolysis (CHH) pathway is the most favorable for bioethanol production, exhibiting the highest ethanol yield at 273 L/tonne dry PTF and a substantial net energy ratio (NER) of 2.2, outperforming supercritical water (SCW) and supercritical carbon dioxide-water (scCO2-H2O) pathways. Moreover, the CHH pathway demonstrates lower carbon footprints of 61 g CO2 per MJ from an environmental perspective and is economically competitive, with an ethanol production cost of $1.11/L, comparable to the enzymatic hydrolysis process. The experimental studies on SWH pretreatment reveal that the yield of total reducing sugar (TRS) was 13% at a temperature of 180°C but declined sharply to around 3% at higher temperatures of 195°C and 210°C, indicating hemicellulose degradation into inhibitory byproducts. These inhibitory byproducts exhibited distinct effects on the fermentation performance of Pichia stipitis (P. stipitis) and Saccharomyces cerevisiae (S. cerevisiae), with inhibitors rendering P. stipitis incapable of producing ethanol from xylose, while ethanol production by S. cerevisiae was delayed by 4 days, and glucose conversion was reduced to 70% compared to uninhibited fermentation. The findings highlight the potential of the CHH pathway for efficient bioethanol production while identifying key challenges and opportunities for process optimization and inhibitor mitigation strategies.

Organizer(s)

Thesis accreditation from IMT Atlantique and the doctoral school Spin, and thesis accreditation from Universitats Indonesia.

 

Keywords : Analytic Hierarchy Process, Fermentation inhibition, Economic analysis, Hydrothermal fractionation, Palm oil by-products, Process simulation, Second-generation bioethanol

Published on 17.06.2024
 
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