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1

Thermogravimetric and Kinetic Analysis of Raw and Torrefied Biomass Combustion

100%

Kopczyński M., Plis A., Zuwała J.

Chemical and Process Engineering

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2015

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vol. 36

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issue 2

209-223

EN

The use of torrefied biomass as a substitute for untreated biomass may decrease some technological barriers that exist in biomass co-firing technologies e.g. low grindability, high moisture content, low energy density and hydrophilic nature of raw biomass. In this study the TG-MS-FTIR analysis and kinetic analysis of willow (Salix viminalis L.) and samples torrefied at 200, 220, 240, 260, 280 and 300 °C (TSWE 200, 220, 240, 260, 280 and 300), were performed. The TG-DTG curves show that in the case of willow and torrefied samples TSWE 200, 220, 240 and 260 there are pyrolysis and combustion stages, while in the case of TSWE 280 and 300 samples the peak associated with the pyrolysis process is negligible, in contrast to the peak associated with the combustion process. Analysis of the TG-MS results shows m/z signals of 18, 28, 29 and 44, which probably represent H2O, CO and CO2. The gaseous products were generated in two distinct ranges of temperature. H2O, CO and CO2 were produced in the 500 K to 650 K range with maximum yields at approximately 600 K. In the second range of temperature, 650 K to 800 K, only CO2 was produced with maximum yields at approximately 710 K as a main product of combustion process. Analysis of the FTIR shows that the main gaseous products of the combustion process were H2O, CO2, CO and some organics including bonds: C=O (acids, aldehydes and ketones), C=C (alkenes, aromatics), C-O-C (ethers) and C-OH. Lignin mainly contributes hydrocarbons (3000-2800 cm−1), while cellulose is the dominant origin of aldehydes (2860-2770 cm−1) and carboxylic acids (1790-1650 cm−1). Hydrocarbons, aldehydes, ketones and various acids were also generated from hemicellulose (1790-1650 cm−1). In the kinetic analysis, the two-steps first order model (F1F1) was assumed. Activation energy (Ea) values for the first stage (pyrolysis) increased with increasing torrefaction temperature from 93 to 133 kJ/mol, while for the second stage (combustion) it decreased from 146 to 109 kJ/mol for raw willow, as well as torrefied willow at the temperature range of 200-260°C. In the case of samples torrefied at 280 and 300°C, the Ea values of the first and second stage were comparable to Ea of untreated willow and torrefied at 200°C. It was also found that samples torrefied at a higher temperature, had a higher ignition point and also a shorter burning time.

2

Impact of torrefaction technique on the moisture contents, bulk density and calorific value of briquetted biomass

100%

Saeed M. A., Ahmad S. W., Kazmi M., Mohsin M., Feroze N.

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EN

The concept of different compositional biomass is introduced to enhance the binding properties and utilize the use of different seasonal biomasses. The effect of densification on the heating values of single pure and mixed compositional biomasses is observed with and without applying special type of pretreatment named as ‘Torrefaction’. The moisture contents and bulk densities were also calculated for these briquettes. The effects of average moisture contents and bulk density (which show the swelling nature) on the heating values are also observed. The experiments have been performed on the pelletizer equipment to form briquetted biomass and bomb calorimeter was used to determine the calorific values of different briquettes. Finally, the percentage decrease in the average moisture contents of different categories of torrefied briquettes from non-torrefied briquettes were also calculated and compared.

3

Thermogravimetric and Kinetic Analysis of Raw and Torrefied Biomass Combustion

86%

Kopczyński M., Zuwała J., Plis A.

Chemical and Process Engineering

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2015

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issue 2

Refine search results

2 Chemical and Process Engineering

1 Polish Journal of Chemical Technology

3 2015

2 Kopczyński M.

2 Plis A.

2 Zuwała J.

1 Ahmad S. W.

1 Feroze N.

1 Kazmi M.

1 Mohsin M.

1 Saeed M. A.

Thermogravimetric and Kinetic Analysis of Raw and Torrefied Biomass Combustion

Impact of torrefaction technique on the moisture contents, bulk density and calorific value of briquetted biomass

Thermogravimetric and Kinetic Analysis of Raw and Torrefied Biomass Combustion