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Author: search.filters.author.Eiad-ua, ApiluckSubject: search.filters.subject.Biomass

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    PRODUCTION OF TORREFIED BIOMASS PELLETS FROM WOODY AND AGRICULTURAL RESIDUES
    (2023-01-01)
    Inthapat, Pimonpan
    ;
    Boontanon, Suwanna Kitpati
    ;
    Prachakittikul, Pensiri
    ;
    Eiad-ua, Apiluck
    ;
    Jadsadajerm, Supachai
    Two different combined process sequences of biomass pretreatment between pelletization after torrefaction (PAT) and pelletization before torrefaction (PBT) were comparatively investigated to produce torrefied biomass pellets (TBP) from woody biomasses, e.g. Leucaena (LC) and rubberwood (RW), and agricultural residues, e.g. rice straw (RS) and sugarcane leaves (SCL). In this study, each sample was thermally treated at 260-300°C for 5 min during torrefaction process. It was found that both woody biomasses and agricultural residues had mass yield lower than 63 wt%, while the bulk density of TBPs were improved higher than 400 kg/m3. For equilibrium moisture content (EMC) analysis, TBPs via PBT method had lower EMC than raw pellet after being kept at 30°C for 12 days. For the thermochemical properties, the TBPs had higher FC, %C, and HHVs than raw pellets in all biomass and increased with torrefaction temperature. When comparing the TBPs between PAT and PBT torrefied pellets, the HHVs of PBT torrefied pellets at 300°C were achieved highest at 27 MJ/kg (dry-ash-free, daf, basis) for SCL sample, which was considered as higher than the standard value at ≥21 MJ/kg of thermally treated biomass pellets (ISO/TS 17225-8:2016) and also in the range at 25.7-28.2 MJ/kg of coal. In addition, the combustion performance index (Sn) of PAT and PBT torrefied pellets was lower than raw pellets, showing a similar property as coal and lignite. Briefly, this study suggests using PBT pretreatment process to produce high quality solid fuel, particularly for agricultural residues such as SCL for a potential substitute of currently used coal.
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    Cattail leaf-derived nitrogen-doped carbons via hydrothermal ammonia treatment for electrocatalytic oxygen reduction in an alkaline electrolyte
    (2022-07-12)
    Panomsuwan, Gasidit
    ;
    Eiad-ua, Apiluck
    ;
    Kaewtrakulchai, Napat
    ;
    Seizawa, Ai
    ;
    Ishizaki, Takahiro
    Cattail leaf-derived nitrogen-doped carbons (CL-NCs) were prepared by hydrothermal treatment in ammonia solution and subsequent pyrolysis for application as catalysts for the oxygen reduction reaction (ORR). The ammonia concentration was varied at 1.0, 1.5, and 2.0 M to alter the nitrogen doping content. The characterization results revealed that CL-NCs exhibited an amorphous structure, while the density of structural defects increased as the ammonia concentration increased. The CL-NC prepared without hydrothermal ammonia treatment had a nonporous structure with a low specific surface area (5 m<sup>2</sup> g<sup>−1</sup>). With hydrothermal ammonia treatment, CL-NCs exhibited a micro–mesoporous structure with a higher surface area (113–496 m<sup>2</sup> g<sup>−1</sup>); however, the surface area was significantly diminished at higher ammonia concentrations due to the deterioration of the pore structure. The nitrogen-doping content in CL-NCs varied from 0.65 to 1.55 atom% with the predominant ratios of pyridinic-N and graphitic-N. For electrochemical evaluation in an alkaline electrolyte (0.1 M KOH), CL-NC prepared at an ammonia concentration of 1.0 M showed the highest ORR activity among all samples, as indicated by the most positive onset potential (−0.05 V vs. Ag/AgCl) and half-wave potential (−0.22 V vs. Ag/AgCl) as well as the highest diffusion-limiting current density with a more favorable reduction via a direct four-electron pathway (n = 3.23–3.52). The ORR activity of CL-NCs had a similar trend to their specific surface area rather than nitrogen doping content, indicating the important role of surface area and porosity in enhancing the ORR activity. Moreover, it possessed excellent stability under long-term operation and exposure to methanol. The results obtained in this work could be helpful information for the further development and utilization of biomass-derived NCs for ORR catalysts.