The 79th Hiroshima University Biomass Evening Seminar (The 59th Hiroshima University ACE Seminar)

The 79th Hiroshima University Biomass Evening Seminar

(The 59th Hiroshima University ACE Seminar)was held.


Date & Time: Mon .18 Nov., 2019   16:20-17:50

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






Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

Lecture: Noah Luciano TAUFER

Visiting Research Scholar, Graduate School of Engineering, Hiroshima University


“Experimental Investigation into the Hydrothermal Carbonization of digestate and the Supercritical Water Gasification of the liquid product”


In the modern world, there is an ever growing need to find and exploit renewable energy sources. Climate change is a world-wide problem that must be confronted and solved. For this reason, renewable energies like biomass, solar, wind and hydropower have taken a strong foothold in the energy market, thanks to large public consensus and government subsidies. Among these, biomass is the most widespread and it is already the fourth largest energy source after coal, oil and natural gas. However, it is not always efficiently exploited through classical thermo-chemical treatments. In fact, a lot of biomass features high moisture content and must be treated with appropriate methods. Hydrothermal treatments are the most effective solution to treat wet biomass. This study investigates the ability of HTC to treat the solid residue of anaerobic digestion of cattle manure, which features very high-water content. Hydrothermal carbonization is performed at 180, 220, 250 °C for residence times of 3 hours under autogenous pressure. The main products, hydrochar (solid) and process liquid, are extracted and analysed. The next step consists in performing Supercritical Water Gasification of the process liquid, minimizing the wastes and producing a valuable gaseous energy vector rich of hydrogen. For this, a continuous flow reactor is used, and the HTC liquid is gasified at 600, 550 and 500 °C and at varying residence times in order to identify the ideal operating parameters. Finally, the solid, liquid and gaseous products are collected and analysed.





Lecture: Hiroki YOKOYAMA

M2 Student, Graduate School of Engineering, Hiroshima University


“Nitrogen Behavior in Supercritical Water Gasification of Glycine at the Initial Stage”


Supercritical water gasification(SCWG) is attracting attention because SCWG can convert biomass quickly, and almost completely. There are some studies about amino acid decomposition under subcritical condition, and they reported that ionic reaction mainly occurred under subcritical condition. On the other hand, it is well known that ion product dramatically decreases under supercritical condition. Discussion about behavior of nitrogen in SCWG in less than 5 s is insufficient though almost all nitrogen reactions are completed in less than 5 s. Therefore, we conducted SCWG of glycine in less than 5 s. The experiment was conducted using a tubular flow reactor at 25 MPa and glycine was used as a model compound of protein of biomass.





Lecture: Rahmat Iman MAINIL

D3 Student, Graduate School of Engineering, Hiroshima University

“Effect of Heating Rate on Supercritical Water Gasification of Palm Oil Mill Effluent”


Palm oil mill effluent (POME) is a problematic waste from palm oil production. It could cause severe pollution if no appropriate management is carried out. Among several technologies employed to utilize biomass waste as a source of energy, supercritical water gasification (SCWG) is the most promising candidate. SCWG is a technology to gasify biomass in hot compress water. The gasification is quick, and high carbon gasification efficiency (CGE) can be achieved. The CGE is known to be affected by the feedstock heating rate. However, the effect of heating rate on the conversion of POME has not understood yet. To study this effect, we treated POME in a continuous flow reactor at a constant temperature of 600 °C and controlled pressure 25 MPa with various preheater length (1,2, and 4 m). By comparing the results, effect of heating rate on the CGE and the phosphorus conversion was made clear.





Lecture: Puji Rahmawati NURCAHYANI

D3 Student, Graduate School of Engineering, Hiroshima University

“Influence of nutrient concentration on the phosphorus consumption and biomass productivity of microalgae Chlorella vulgaris.”


Microalgae are a photosynthetic biomass which grow faster compared to the land plant. In the growing period, these green algae need some nutrient with main composition of nitrogen, phosphorus and potassium. However, the consumption behavior of those nutrient has not been reported well. Therefore, we set this experiment to investigate the green microalgae Chlorella vulgaris in uptake of phosphorus for growing their biomass. The cultivation was set in batch reactor with volume of 900 ml. Room temperature was controlled for 20 oC, aeration was fed into the reactor with flowrate of 3 ml/min and the light intensity was 3.42 µmoles/m2/s with 24 h photoperiod. The medium concentration used was 10, 50, 100, 200 and 500 ppm. During cultivation period, microalgae sample were taken once in every 3 days and stopped in day 40th. We analyzed the cell weight of per ml sample. Other than that, we analyzed the phosphorus content in the medium using molybdenum blue method. As a result, the maximum biomass productivity was obtained in nutrient concentration of 100 ppm, while the consumption of phosphorus rate on this concentration was faster than that of the others. Furthermore, the use of higher concentration of phosphorus might inhibits the growth of microalgae cells.


Chair: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University