Elucidation of the unsteady pyrolysis mechanism of combustible solids based on in situ visualization

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04331
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Akita Prefectural University
• Principal Investigator: Daitoku Tadafumi 秋田県立大学, システム科学技術学部, 助教 (40452049)
• Co-Investigator(Kenkyū-buntansha): 鶴田 俊 秋田県立大学, システム科学技術学部, 教授 (90197773)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: イメージング / 熱分解 / 熱物質移動 / 固体燃焼

Outline of Final Research Achievements

In this study, the microscopic visualization of the pyrolysis of woody biomass was conducted using the BL20B2 beamline at “SPring-8,” a large synchrotron radiation facility. Changes in the shape and internal structure of the woody biomass were visualized using ultra-high-speed computerized tomography (CT). The sample was a Japanese cypress wood with a height of 5 mm and diameter of 5 mm. We used radiation as the heat source to achieve a high heat flux. When the heat flux is high, the sample expands. Gaps were observed in the sample. Compared with the experimental results under the low heat flux obtained in the previous study, we observed a completely different aspect. In a nitrogen or air atmosphere, the internal structure of the wood during transient pyrolysis was visualized using ultra-high-speed X-ray CT. In addition, the schlieren method was used to study the pyrolysis behavior of the woody biomass and the behavior of the pyrolysis gases.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

持続可能なバイオマスエネルギー利用の観点から，本研究では木質系バイオマスを対象とし，エネルギー変換技術への貢献を目指した．熱分解により内部に温度および構造の分布を生じる条件下において，試料の内部が変化していく過程を放射光X線による超高速非破壊可視化手法を適用した．熱分解により時々刻々と変化する内部構造を定量的に評価することが可能となった．本研究では木質系バイオマスを対象としたが，得られた結果は，ひいては，熱的に厚みを持った固体の燃焼および熱分解現象について，内部構造の非定常変化を考慮した理論構築の進展が期待できると考える．