The 52nd Hiroshima University Biomass Evening Seminar(The 11th Hiroshima University ACE Seminar)

The 52nd Hiroshima University Biomass Evening Seminar

(The 11th Hiroshima University ACE Seminar)was held.


Date & Time:Wed .26  Apr., 2017   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University




Commentary: Yukihiko MATSUMURA

        Professor, Institute of Engineering, Hiroshima University


Lecture: Kiyoto KIHARA

          M2 Student, Graduate School of Engineering, Hiroshima University

“Effect of Carbon Nanotube Catalysts on Hydrothermal Pretreatment and Enzymatic Hydrolysis”


Recently, bioethanol has attracted attention for alternative energy of oil, and water hyacinth (WH) is considered as potential feedstock.  Many researches have studied water hyacinth which is lignocellulosic biomass and does not compete with food.  To obtain bioethanol from lignocellulosic biomass, the biomass has to go through the three processes: pretreatment, enzymatic hydrolysis and fermentation. Lignocellulosic biomass has strong structure that has to be destroyed.  Hydrothermal pretreatment is one of the most famous pretreatment.  Many researchers used some catalyst.  Among them, carbon nanotube (CNT) has a large specific surface area, and CNT treated by sulfonic acid showed good effect on biodiesel production. In this study, we examined the effectiveness of acid treated CNT (A-CNT) catalyst on hydrothermal treatment and enzymatic hydrolysis.  Further, we examined the influence of temperatures.  WH was hydrothermally treated without catalyst, with CNT catalyst, or with A-CNT catalyst.  Temperature was set at 200 oC, 250 oC or 300 oC.  Enzymatic hydrolysis temperature was 50 oC. Enzymes were cellulose and β-glucosidase.  Glucose yield was analyzed by HPLC.



Lecture: Novi SYAFTIKA

D2 Student, Graduate School of Engineering, Hiroshima University

“ Hydrothermal pretreatment of rice residues with biodiesel waste as the medium”

Agricultural waste is becoming more popular as cellulosic biomass for bioethanol production because it is not competing with human food supply. Rice is the largest agriculture product of Japan including in the small district in Oasa, Kita Hiroshima, Hiroshima Prefecture.  As the consequence, rice husk is produced annually in large amount in this region. Rice husk is mostly remains unutilized and it contains cellulose. Therefore, it has the potential to be converted into bioethanol. Hydrothermal process is known as environmental friendly pretreatment technique to convert cellulosic biomass into various products including bioethanol since it is using hot compressed water solely as the medium. However, studies shown that catalyst addition improve the yield of products. Alkali catalyst like sodium hydroxide is often used in hydrothermal pretreatment since it is low cost chemical and easily obtained. Nonetheless, the reduction of catalyst cost will be beneficial to make bioethanol more economically competitive. Interestingly, in district of Oasa, Kita Hiroshima Japan, biodiesel has been produced from vegetable cooking oil waste and being utilized for diesel engine vehicles. This biodiesel production generates biodiesel waste that has very high pH (alkaline) and treatment is required to neutralized it before discarding it into the environment. In this research, the possibility of using the alkali characteristic in biodiesel waste to replace commercial alkali catalyst for hydrothermal pretreatment of rice husk is studied. The study was conducted using autoclave reactor made from stainless steel. The experiments were carried out at reaction temperatures of 150, 200 and 250 °C, reaction times of 30 min, and the biodiesel wastewater addition was compared with water with and without alkali catalyst. To measure the effectiveness of pretreatment, enzymatic hydrolysis was employed after pretreatment to obtain glucose yield. The effect of biodiesel waste addition on rice husk conversion to glucose by hydrothermal pretreatment at various temperature was elaborated.



Lecture: Nattacha PAKSUNG    

         D3  Student, Graduate School of Engineering, Hiroshima University

“Hydrothermal gasification of glucose, xylose and guaiacol as model compounds of lignocellulosic biomass ”

Supercritical water gasification (SCWG) is one promising technology to convert biomass into renewable energy because supercritical water behaves like organic solvent, thus biomass could dissolve in the water at this state (temperature and pressure above 374 °C and 22.1 MPa, respectively).  It has high conversion efficiency to produce gas fuel and relatively high hydrogen selectivity. Lignocellulosic biomass composes mainly of cellulose, hemicellulose and lignin, whose smaller units are glucose, xylose, and guaiacol respectively.  Reaction scheme and model compound of biomass are keys to achieve the goal.  Thereby, the objective of research is to study the interaction between model compounds consisted in lignocellulosic biomass in varied composition in hydrothermal conditions



Lecture:  Tanawan  CHALERMSAKTRAKUL                    

         M2  Student, Graduate School of Engineering, Hiroshima University

“Supercritical water gasification of xylose and acetic acid mixture ”


The hydrothermal gasification of xylose, as a model substance of hemicellulose, was carried out at high temperatures and pressures (up to 400-450 °C, 25 MPa) in the presence of acetic acid by using continuous-flow reactor. As acetic acid is one kind of organic compound, environmental friendly, low corrosiveness, and also byproduct of hemicellulose gasification, it was chosen to be the catalyst to understand more about the behavior of each reaction in supercritical gasification of xylose. This study aimed to compare the reaction rate constant of xylose decomposition with and without acetic acid addition. The experiments were investigated to determine the influence of residence time varied from 0.5 to 5 s. The concentration of xylose was 1.5 wt% mixed with 1.5 wt% of acetic acid. When acetic acid was added in supercritical gasification of xylose, it acted as radical scavenger and provided H+, so the retro-aldol reaction and carbon gasification production, which are radical reactions, were be suppressed. Meanwhile, the dehydration of xylose and xylulose to furfural was be promoted significantly.



Chair: Obie FAROBIE

    Visiting Reseacher, Institute of Engineering, Hiroshima University