Ingeniería y Arquitectura

URI permanente para esta comunidadhttps://hdl.handle.net/11441/11290

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Examinando Ingeniería y Arquitectura por Premio "Premio Mensual Publicación Científica Destacada de la US. Facultad de Física"

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    Acceso AbiertoPremio Mensual Publicación Científica Destacada de la US. Facultad de FísicaArtículo
    Performance improvement in olive stone's combustion from a previous carbonization transformation
    (Elsevier, 2018-09) Gómez Martín, Aurora; Chacartegui, Ricardo; Ramírez Rico, Joaquín; Martínez Fernández, Julián; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Ingeniería Energética; Ministerio de Economía y Competitividad (MINECO). España
    Under the framework of circular economy, agricultural wastes are an interesting carbon-based feedstock for thermal energy and power generation. Their use could extend the availability of biomass-based fuel and, at the same time, would reduce negative environmental effects. However, depending on the residues’ characteristics, their direct combustion in boilers presents some challenges which could be overcome with a carbonization pre-treatment. In this paper, the main mechanisms of thermochemical transformation of an abundant agricultural waste, olive stone, into biochar products via slow carbonization are analyzed, with emphasis on the effect of peak carbonization temperature. Thermogravimetric and differential scanning calorimetry analysis are used to evaluate the performance of the resulting biochars compared to raw olive stone in combustion processes and to assess the correlation between the peak carbonization temperature and compositional and fuel properties. Results show that with a prior treatment up to an optimum temperature of 800 °C the energy density is increased up to three times compared to the raw material. These findings suggest that carbonization of olive stones reduces the barriers to their direct use in current biomass boiler technology.
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    Acceso AbiertoPremio Mensual Publicación Científica Destacada de la US. Facultad de FísicaArtículo
    Phosphogypsum waste lime as a promising substitute of commercial limes: A rheological approach
    (Elsevier, 2019) Romero Hermida, Isabel; Borrero-López, Antonio María; Alejandre Sánchez, Francisco Javier; Flores Alés, Vicente; Santos, A.; Franco, J. M.; Esquivias Fedriani, Luis María; Universidad de Sevilla. Departamento de Física de la Materia Condensada; Universidad de Sevilla. Departamento de Construcciones Arquitectónicas II (ETSIE)
    This paper presents the rheological properties of three types of lime putty, specifying the influence of their origin. The study aims to compare a special lime putty prepared from phosphogypsum with a commercial lime powder and an aged lime putty. The results obtained in terms of chemical composition, crystalline structure, grain size and rheological characterization, (linear viscoelasticity, shear rate and time-dependent flow behaviour) are presented in the study. Putties studied present a similar rheological response, which mainly depends on the particle size and water content. Lower values of the linear viscoelastic functions and viscosity were found for the phosphogypsum lime putty, in agreement with the higher particle size. Transient flow tests reveal a predominant elastic response with no significant shear-induced structural perturbations. However, either a thickening phenomenon over time, i.e. rheopexy, favoured at low shear rates, or a viscosity decrease, i.e. thixotropy, favoured at high shear rates, was observed.