Particle pyrolysis modeling and thermal characterization of pecan nutshell

Medrano, José Ángel Loredo; Martínez, Diana Bustos; Rosa, Javier Rivera De la; Pedraza, Eileen; Flores-Escamilla, Gerardo A.; Ciuta, Simona

doi:10.1007/s10973-016-5541-4

Cited by 14 publications

(3 citation statements)

References 21 publications

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“…The activation energy of the rate-determining step in pathway c-4 is 455.4 kJ/mol, which is the lowest among the four pathways. It should be pointed out that the activation energy (455.4 kJ/mol) is higher than that of the pyrolysis of hemicellulose, cellulose, or lignin [26]. The main reason can be attributed to the different initial reaction model compounds.…”

Section: Resultsmentioning

confidence: 99%

Theoretical Investigation of the Formation Mechanism of NH3 and HCN during Pyrrole Pyrolysis: The Effect of H2O

et al. 2018

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Coal is a major contributor to the global emission of nitrogen oxides (NOx). The NOx formation during coal utilization typically derives from the thermal decomposition of N-containing compounds (e.g., pyrrolic groups). NH3 and HCN are common precursors of NOx from the decomposition of N-containing compounds. The existence of H2O has significant influences on the pyrrole decomposition and NOx formation. In this study, the effects of H2O on pyrrole pyrolysis to form NOx precursors HCN and NH3 are investigated using the density functional theory (DFT) method. The calculation results indicate that the presence of H2O can lead to the formation of both NH3 and HCN during pyrrole pyrolysis, while only HCN is formed in the absence of H2O. The initial interaction between pyrrole and H2O determines the N products. NH3 will be formed when H2O attacks the C2 position of pyrrole with its hydroxyl group. On the contrary, HCN will be generated instead of NH3 when H2O attacks the C3 position of pyrrole with its hydroxyl group. In addition, the DFT calculations clearly indicate that the formation of NH3 will be promoted by H2O, whereas the formation of HCN is inhibited.

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Section: Resultsmentioning

confidence: 99%

Theoretical Investigation of the Formation Mechanism of NH3 and HCN during Pyrrole Pyrolysis: The Effect of H2O

et al. 2018

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“…For the specific case of pecan shells, contradictory information has been found. Fasina [43] suggested that the pyrolysis of this material is predominantly endothermic, while Loredo [44] maintains that the pyrolysis of walnut shell is slightly exothermic within the range of 236-360 • C. El Hamdouni's [45] comparative experiment of combustion with pyrolysis of walnut shells revealed a significantly higher exothermic nature in combustion compared to almost negligible energy release during pyrolysis in differential scanning calorimetry (DSC).…”

Section: Latent Heat and Interpretation Of Pyrolysis Stagesmentioning

confidence: 99%

Analysis of the Solar Pyrolysis of a Walnut Shell: Insights into the Thermal Behavior of Biomaterials

Aspiazu-Méndez,

Cisneros-Cárdenas,

Pérez-Rábago

et al. 2024

Energies

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The state of Sonora, Mexico, stands as one of the leading producers of pecan nuts in the country, which are commercialized without shells, leaving behind this unused residue. Additionally, this region has abundant solar resources, as shown by its high levels of direct normal irradiance (DNI). This study contributes to research efforts aimed at achieving a synergy between concentrated solar energy technology and biomass pyrolysis processes, with the idea of using the advantages of organic waste to reduce greenhouse gas emissions and avoiding the combustion of conventional pyrolysis through the concentration of solar thermal energy. The objective of this study is to pioneer a new experimental analysis methodology in research on solar pyrolysis reactors. The two main features of this new methodology are, firstly, the comparison of temperature profiles during the heating of inert and reactive materials and, secondly, the analysis of heating rates. This facilitated a better interpretation of the observed phenomenon. The methodology encompasses two different thermal experiments: (A) the pyrolysis of pecan shells and (B) the heating–cooling process of the biochar produced in experiment (A). Additionally, an experiment involving the heating of volcanic stone is presented, which reveals the temperature profiles of an inert material and serves as a comparative reference with experiment (B). In this experimental study, 50 g of pecan shells were subjected to pyrolysis within a cylindrical stainless-steel reactor with a volume of 156 cm3, heated by concentrated radiation from a solar simulator. Three different heat fluxes were applied (234, 482, and 725 W), resulting in maximum reaction temperatures of 382, 498, and 674 °C, respectively. Pyrolysis gas analyses (H2, CO, CO2, and CH4) and characterization of the obtained biochar were conducted. The analysis of heating rates, both for biochar heating and biomass pyrolysis, facilitated the identification, differentiation, and interpretation of processes such as moisture evaporation, tar production endpoint, cellulosic material pyrolysis, and lignin degradation. This analysis proved to be a valuable tool as it revealed heating and cooling patterns that were not previously identified. The potential implications of this tool would be associated with improvements in the design and operation protocols of solar reactors.

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“…Although pecan wastes have been studied as a feedstock for bioenergy purposes [ 22 ], and their main components have been determined [ 23 , 24 ], specific information on their properties for biofuel briquettes elaboration is scarce. Therefore, the present study aimed to determine the most appropriate particle size from pecan pericarp feedstock materials for biofuel briquettes production, to optimize the briquetting process, for the prevention of material lose during production, transportation, and storage; and to investigate how the energy content and fuel quality of pecan briquettes differ among the functional groups.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Characteristics of Biofuel Briquettes Made from Pecan (Carya illinoensis) Pericarp Wastes of Different Particle Sizes

et al. 2022

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Pecan nut (Carya illinoensis) pericarp is usually considered as a waste, with no or low value applications. Its potential as a densified solid biofuel has been evaluated, searching for alternatives to generating quality renewable energy and reducing polluting emissions in the atmosphere, based on particle size, that is an important feedstock property. Therefore, agro-industrial residues from the pecan nut harvest were collected, milled and sieved to four different granulometry: 1.6 mm (N° 12), 0.84 mm (N° 20), 0.42 mm (N° 40), and 0.25 mm (N° 60), used as raw material for biofuel briquette production. The carbon and oxygen functional groups in the base material were investigated by Fourier transform infrared spectroscopy (FTIR) and proximate analyses were performed following international standards, for determining the moisture content, volatile materials, fixed carbon, ash content, and calorific value. For the biofuel briquettes made from base material of different particle sizes, the physical characteristics (density, hardness, swelling, and impact resistance index) and energy potential (calorific value) were determined to define their quality as a biofuel. The physical transformation of the pecan pericarp wastes into briquettes improved its quality as a solid biofuel, with calorific values from around 17.00 MJ/kg for the base material to around 18.00 MJ/kg for briquettes, regardless of particle size. Briquettes from sieve number 40 had the highest density (1.25 g/cm3). Briquettes from sieve number 60 (finest particles) presented the greater hardness (99.85). The greatest susceptibility to swelling (0.31) was registered for briquettes with the largest particle size (sieve number 20). The IRI was 200 for all treatments.

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Particle pyrolysis modeling and thermal characterization of pecan nutshell

Cited by 14 publications

References 21 publications

Theoretical Investigation of the Formation Mechanism of NH3 and HCN during Pyrrole Pyrolysis: The Effect of H2O

Theoretical Investigation of the Formation Mechanism of NH3 and HCN during Pyrrole Pyrolysis: The Effect of H2O

Analysis of the Solar Pyrolysis of a Walnut Shell: Insights into the Thermal Behavior of Biomaterials

Physicochemical Characteristics of Biofuel Briquettes Made from Pecan (Carya illinoensis) Pericarp Wastes of Different Particle Sizes

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