Analysis of kinetic and diffusive data from the combustion of char pellets made with hybrid mixtures

Marques, Edmundo; Ferreira, Tânia; Pereira, Carlos; Paiva, João Monney; Pinho, Carlos

doi:10.1016/j.energy.2019.05.188

Cited by 5 publications

(3 citation statements)

References 14 publications

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“…Several works have focused on the production and characterization of ash resulting from the combustion of biomass, whether resulting from residual biomass or from biomass-derived fuels such as wood pellets. Exploratory works involving the characterization of the biomass types analyzed in the present work have been presented from the perspective of energy recovery, such as the work presented by Marques et al (2011), where the possibility of pellet production from species belonging to the genera Cytisus and Cistus is analyzed [30], or the work presented by Marques et al (2019), where the characterization of charcoals produced with blends of Cytisus with cork residues, Cistus with Eucalyptus and Cytisus with Cistus is presented [31]. The results obtained in this study show a very wide dispersion, and following the results obtained in previous works, the species Cytisus striatus has the lowest ash value of 1.32%, followed by a set of 7 more species, namely, Pterospartum tridentatum, Erica australis, Genista falcata, Erica lusitanica, Cytisus multiflorus, Erica arborea and Cistus The volatile content is another parameter that has a direct impact on how these materials behave during combustion, and this perspective can be analyzed not only for the moment of energy recovery, but also to analyze the perspective of the behavior of these species in rural fires.…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 99%

Energy Recovery of Shrub Species as a Path to Reduce the Risk of Occurrence of Rural Fires: A Case Study in Serra da Estrela Natural Park (Portugal)

Nunes

Raposo

Meireles

et al. 2021

Fire

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The accumulation of biomass fuels resulting from the growth of heliophilous shrubs and small tree species at the edge of forests and on scrub and pasture lands contributes to the increased risk of rural fires in Mediterranean climate regions. This situation has been managed with a set of legislative measures launched with the objective of promoting cleaning and the control of these species. Areas of scrub and pasture already constitute the largest part of the annually burnt area in Portugal, resulting in high-intensity fires. In the present study, shrubs and small tree species were characterized in the laboratory. Thermogravimetric, chemical and calorimetric analyses for the evaluation of the potential for the energy recovery of the selected species were carried out. It was observed that energetic valorization (i.e., to enhance the value by planned actions) of these species is difficult because they present high levels of ash and metals, becoming prone to the occurrence of fouling and slagging phenomena. Thus, the creation of value chains that justify the incorporation of these materials becomes very difficult, except if used in non-certified, small-scale and locally based processes. The possibility of recovery through thermochemical conversion processes, such as torrefaction, pyrolysis or gasification, must be studied so that more efficient and feasible recovery alternatives can be found, allowing for the creation of value chains for these residual materials to promote their sustainable management and, thus, mitigate the risk of rural fires occurring.

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Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 99%

Energy Recovery of Shrub Species as a Path to Reduce the Risk of Occurrence of Rural Fires: A Case Study in Serra da Estrela Natural Park (Portugal)

Nunes

Raposo

Meireles

et al. 2021

Fire

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“…During the literature review conducted in this study, relevant works in biomass combustion in fluidized beds, specifically charcoal [22][23][24][25], were identified, along with several works developed in chemical kinetics [26][27][28][29]. However, the investigation of charcoal burning in other combustion systems, such as the traveling bed system, is still limited and requires additional analysis.…”

Section: Introductionmentioning

confidence: 99%

The Experimental Analysis of Biochar Combustion in a Traveling Grate Furnace

Ferreira,

Paiva,

Pinho

2024

Fire

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The current energy policy targets reducing energy dependence and minimizing pollutant emissions. Therefore, with the growing interest in using biomass as an alternative energy source, conducting scientific studies on its behavior and optimizing the respective conversion systems has become imperative. The present study focuses on investigating the combustion of biochar pellets in a laboratory-scale traveling grate furnace at three different bed temperatures: 700, 750, and 800 °C. The biochars were obtained via the carbonization process of Pinus pinaster, Acacia dealbata, and Cytisus scoparius pellets. The biochar combustion was studied using a moving-bed carbon particle burning model, supported by kinetic information which was obtained via the combustion of the same biochars in a bubbling fluidized bed. The diffusive parameter which was representative of this traveling grate combustion technology was determined, particularly the bed bypass factor. The combustion tests were carried out with the incomplete combustion of the char pellets. In general, the increase in biochar size led to a decrease in the bypass factor. However, the furnace temperature did not influence this parameter.

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“…In a word, the particle bulk density of biomass may not only affect the biomass pyrolysis but be a critical factor affecting biomass combustion due to the inevitable changes in bed bulk characteristics caused by the different shapes and sizes of biomass particles. In the early stages of biomass combustion, hemicellulose, and cellulose release volatile matter, which ignites after reaching a certain temperature and oxygen level (Marques et al 2019). The heat generated by the combustion of volatile matter provides energy for subsequent release and ignition.…”

Section: Introductionmentioning

confidence: 99%

Combustion and flue gas evolution characteristics of rice husk in various mixtures and layers with Al2O3 particles and char prepared with different pyrolysis parameters

Dong,

Wang,

Huan

et al. 2023

BioRes

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During pyrolysis and combustion experiments, rice husk and Al2O3 were combined in two ways, namely blending (rice husk was blended with Al2O3) and covering (rice husk was covered by Al2O3) modes, respectively. Rice husk biomass (RHB) char was prepared under different pyrolysis conditions. The resulting combustion characteristics and corresponding gaseous evolution of the biochar were compared. The maximum combustion rate decreased as particles accumulated, causing a shift in the thermo-gravimetric curve to higher temperature ranges. The combustion reaction was hindered in the covering mode. The combustion reactivity of the prepared char decreased as the char preparation time increased. During the char oxidation process, the release amounts of H2O and CO2 from char combustion increased first and then decreased, while the release amounts of CO, CH4, and organic components containing C=O gradually decreased with increasing char preparation time. Char prepared with the covering mode exhibited higher burn-out rates and combustion indices but lower activation energies required for combustion reaction. Additionally, the covering mode delayed the timely release of gases from the biomass heating in air, and the quantity of combustion gas released from the char produced at covering mode was greater than that released from the char produced at blending mode. The results obtained can improve the understanding of stacked biomass particles combustion process.

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Analysis of kinetic and diffusive data from the combustion of char pellets made with hybrid mixtures

Cited by 5 publications

References 14 publications

Energy Recovery of Shrub Species as a Path to Reduce the Risk of Occurrence of Rural Fires: A Case Study in Serra da Estrela Natural Park (Portugal)

Energy Recovery of Shrub Species as a Path to Reduce the Risk of Occurrence of Rural Fires: A Case Study in Serra da Estrela Natural Park (Portugal)

The Experimental Analysis of Biochar Combustion in a Traveling Grate Furnace

Combustion and flue gas evolution characteristics of rice husk in various mixtures and layers with Al2O3 particles and char prepared with different pyrolysis parameters

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