Browsing by Author "A. de Carvalho, João"

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Statistical Analysis of the Droplet Size Distribution of Tire Pyrolysis Oil-Diesel Oil Sprays
(Universidad Nacional Autónoma de Tayacaja Daniel Hernández Morillo - UNAT, 2021-12-15) R. Gamboa, Alexander; R. dos Santos, Leila; A. Martins, Cristiane; A. de Carvalho, João
The liquid product obtained from tire pyrolysis process, called tire pyrolysis oil (TPO), has a great attraction as an alternative fuel, as it has a viscosity of 5.43 cSt (Sharma et al., 2016), density of 921 kg/m³ (Gamboa et al., 2020), surface tension of 0.028 N/m (Chumpitaz et al., 2019), and higher heating value of 46.32 MJ/kg (Das et al., 2017), which are similar to diesel oil. These physical and chemical properties have motivated research into its application in furnaces, boilers and compression ignition engines. Generally, TPO is blended with diesel or biodiesel in order to decrease the percentage of sulfur and improve the cetane number of the fuel blend (Sharma et al., 2016). However, the evaluation of the quality and applicability of TPO has been focused mainly on combustion emissions and the performance of thermal equipment fueled with this fuel (and diesel/biodiesel blends), where the atomization process has been ignored, which is closely linked with the efficiency of liquid fuel evaporation and combustion. Thus, in this work, an evaluation of the atomization quality of blends of tire pyrolysis oil and diesel oil was carried out based on the comparison of the uniformity parameters of the drop size distribution of fuel sprays. The distribution function used was the Log-Normal function, as it allowed reconstructing the droplet size distribution of the sprays with only the mass median diameter and Sauter mean diameter. These values were measured using the Malvern Spraytec laser diffraction system model STP5936 (Chumpitaz et al., 2019). The fuel sprays were generated with a twin-fluid atomizer (type Y-jet) operating at air-to-fuel mass ratio (RAL) in the range of 0.05 to 0.35. The results showed that the higher the percentage by mass of TPO in the fuel blend, the lower the uniformity of the spray. Furthermore, a uniform TPO-DO spray with smaller mean diameters (<30 μm) can be achieved if sufficiently high RAL values (>0.15) are applied and percentages of TPO in the blend less than 5% are used.
Thermodynamic study of syngas combustion in gas microturbines with regeneration composed with metallic and ceramic materials
(Universidad Nacional Autónoma de Tayacaja Daniel Hernández Morillo - UNAT, 2021-12-15) Amaro, Jordan; Z. Mendiburu, Andrés; A. de Carvalho, João
The objective of this research is to carry out an energetic evaluation of syngas combustion in gas microturbines with regenerators made with two different types of material: metallic or ceramic. A modified chemical equilibrium model was used to calculate syngas composition obtained from sugarcane bagasse gasification in a fluidized bed gasifier using steam as gasifying agent. For the gas microturbines with a regenerator of metallic materials, combustion temperatures of 850, 900, and 950 °C were established; and for those with a regenerator of ceramic materials, combustion temperatures of 1150, 1250, and 1350 °C were established. The range for the compression ratio was 2 to 6, and the excess air percentages employed were 400, 500, and 600%. Excellent results were obtained: maximum power ratio was 1.87 kWh/Nm3, maximum cycle efficiency was 57%, and maximum regenerator effectiveness was 100%. Thus, syngas combustion performance in the gas microturbines with regeneration was excellent.