Estimation of energy properties of torrefied Japanese cedar with colorimetric values

Sawai, Toru; Katayama, Ichiro; Ida, Tamio; Imamura, Hiroki; Kajimoto, Takeshi

doi:10.1299/mej.16-00320

Cited by 5 publications

(5 citation statements)

References 15 publications

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“…Severe (250-8, 250-10, and 250-12) biomass torrefaction temperature, therefore, causes a darker colour in the pellets (Figure 1). This color change with the increasing of temperature agrees with the color change occurred in pellets fabricated with Japanese cedar [31] and branches of birch and spruce [32].…”

Section: Appearance Of Pellet With Torrefied Biomasssupporting

confidence: 86%

Physical and Compression Properties of Pellets Manufactured with the Biomass of Five Woody Tropical Species of Costa Rica Torrefied at Different Temperatures and Times

et al. 2017

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Abstract:The purpose of the biomass torrefaction and pelletizing processes is to increase its energy properties, be environmentally friendly, decrease shipping costs, and make handling easier. The objective of the present work is to evaluate the density, internal density variation by X-ray densitometry, moisture content, water absorption, and compression force of torrefied biomass pellets of five wood species (Cupressus lusitanica, Dipterix panamensis, Gmelina arborea, Tectona grandis, and Vochysia ferruginea) under three torrefaction temperature conditions (light, middle, and severe) and three torrefaction times (8, 10, and 12 min). The results showed that the bulk density of the pellets was 0.90-1.30 g/cm 3 . The density variation of the pellets was higher with torrefaction at 250 • C. The moisture content decreased with increasing torrefaction temperature from 3% to 1%. Water absorption was lower in the pellets torrefied at 250 • C. The compression force was lower in the pellets torrefied at 250 • C with approximate loads of 700 N. Based on the above results, it was concluded that pellets made with biomass torrefied at 200 • C have better energy properties and evaluated properties. According to these results, pellets fabricated with the torrefied biomass of tropical species can be used in stove, gas, and hydrogen production because the pellet presents adequate characteristics.

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Section: Appearance Of Pellet With Torrefied Biomasssupporting

confidence: 86%

Physical and Compression Properties of Pellets Manufactured with the Biomass of Five Woody Tropical Species of Costa Rica Torrefied at Different Temperatures and Times

et al. 2017

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“…Currently, there are two types of torrefaction technologies, one is the dry torrefaction (DT) and the other is the wet torrefaction (WT). The former DT is a conventional torrefaction which is carried out at temperature of 200-300 ℃ in an inert gas environment under atmospheric pressure, and a large number of studies have been conducted (Sano and Honjyo, 2011;Stelt et al, 2011;Chen et al, 2015Chen et al, , 2021Sawai et al, 2017;Yoshida et al, 2018;Cahyanti et al, 2020). The latter WT is carried out in hydrothermal media or hot…”

Section: Introductionmentioning

confidence: 99%

Wet torrefaction kinetics and heating value estimation for wet torrefied Japanese cedar and rice straw

INOUE,

TAMAKOSHI,

SAWAI

2024

JTST

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One effective measure to achieve carbon neutrality is to shift away from coal. Wet torrefied biomass (WTB) can be the promising solid biofuels to replace coal, when high moisture content biomass is used as feedstock. To utilize WTB for industrial use, WTB with predetermined energy properties such as higher heating value (HHV) and solid mass yield (SMY) has to be produced to meet the requirement in coal-fired power plants and industrial boilers. In this study, the analytical approach to estimate SMY and HHV of WTB for given wet torrefaction (WT) process parameters, temperature and residence time is investigated for Japanese cedar and rice straw. The Van Krevelen diagram shows that dehydration is considered as a main reaction of WTB, which is the same result as the previous studies on dry torrefied biomass (DTB). HHVs of WTB as well as DTB are well correlated with its SMY, and the experimental correlations of HHV are proposed as a function of SMY. The difference in HHV of rice straw between WTB and DTB and the difference in HHV between Japanese cedar and rice straw are closely related to the difference in ash content and the ash removal effect in WT process. The WT reaction based on volatile release is modeled as the single reaction with only one reaction rate constant of volatiles evolved. It is found that the solid-state reaction function codes F12 and D1 are the most suitable for Japanese cedar and rice straw, and kinetic parameters in WT process are determined. The estimation method of SMY and HHV is proposed based on the WT kinetic model and the HHV experimental correlation. It is found that the WT temperature and residence time to produce WTB with predetermined SMY and HHV can be provided by the proposed estimation method within an accuracy of about 10%.

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“…But the higher heating value (HHV) of torrefied biomass has been evaluated by means of experimental approaches for various biomass species so far. That is, the torrefaction conditions to produce torrefied solid biofuel with predetermined HHV have been provided only empirically (Stelt et al, 2011;Shang et al, 2012;Strandberg et al, 2015;Sawai et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Generalized heating value estimation of torrefied woody biomass based on pyrolysis kinetics of primary constituent polymers

Sawai

Yokota

Tagami-Kanada

2022

JTST

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In 2021, more than 40 countries have agreed with "de-coal" statement at the COP26. The torrefied solid biofuels have come to attract attention as promising alternative fuels to coal in coal-fired power plants and industrial boilers. However, the energy property such as higher heating value (HHV) and energy yield of torrefied biomass, which is one of the most important fuel properties, has been evaluated by means of experiments for various biomass species so far. That is, the torrefaction conditions to produce torrefied solid biofuel with predetermined HHV have been provided only empirically. In this study, a generalized HHV estimation method applicable to any torrefied woody biomass is investigated based on pyrolysis kinetics of primary constituent polymers of woody biomass, cellulose, lignin and xylan. Analyses of pyrolysis kinetics of constituent polymers are conducted by assuming that the process in non-isothermal pyrolysis experiments is modeled as the single reaction. The HHVs of torrefied constituent polymers are obtained by isothermal torrefaction experiments, and the experimental correlations of HHV of torrefied constituent polymers are proposed as a function of solid mass yield. For a given woody biomass whose mass fractions of three constituent polymers are known, HHV of torrefied woody biomass produced with any torrefaction condition can be estimated by applying pyrolysis kinetic models and experimental correlations of HHV for three constituent polymers to the torrefaction process of woody biomass. From the comparison between estimated HHV of torrefied woody biomass and experimental data, it is concluded that the generalized HHV estimation method can be useful for evaluating HHV of torrefied woody biomass with about 10% accuracy, although the HHV is somewhat underestimated.

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Estimation of energy properties of torrefied Japanese cedar with colorimetric values

Cited by 5 publications

References 15 publications

Physical and Compression Properties of Pellets Manufactured with the Biomass of Five Woody Tropical Species of Costa Rica Torrefied at Different Temperatures and Times

Physical and Compression Properties of Pellets Manufactured with the Biomass of Five Woody Tropical Species of Costa Rica Torrefied at Different Temperatures and Times

Wet torrefaction kinetics and heating value estimation for wet torrefied Japanese cedar and rice straw

Generalized heating value estimation of torrefied woody biomass based on pyrolysis kinetics of primary constituent polymers

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