Departamento de Ingeniería Mecánica y Minera

URI permanente para esta comunidadhttps://hdl.handle.net/10953/41

En esta Comunidad se recogen los documentos generados por el Departamento de Ingeniería Mecánica y Minera y que cumplen los requisitos de Copyright para su difusión en acceso abierto.

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Mostrando 1 - 8 de 8

Convective drying of mango stone for use as biomass.
(ELSEVIER, 2023-06) Gómez-de la Cruz, Francisco J.; Palomar-Torres, Amalia; Pérez-Latorre, Francisco J.; Cruz-Peragón, Fernando
Mango stone is an interesting biomass by-product with a considerable net calorific value. Mango production has significantly risen in the last few years, meaning that mango waste has increased as well. However, mango stone has a moisture content of about 60% (wet basis) and it is very important to dry the samples for using them in electrical and thermal energy production. In this paper, the main parameters involved in the mass transfer during drying are determined. Drying was carried out in a convective dryer through a set of experiments based on five drying air temperatures (100ºC, 125ºC, 150ºC, 175ºC and 200ºC) and three air velocities (1 m/s, 2 m/s and 3 m/s). Drying times ranged between 2 and 23 hours. The drying rate was calculated from the Gaussian model whose values ranged from 1.5·10-6 to 6.3·10-4 s-1. Effective diffusivity was obtained as an overall parameter in the mass diffusion for each test. These values were found between 0.71·10-9 and 13.6·10-9 m2/s. The activation energy was calculated from the Arrhenius law for each test, made at different air velocities. These values were 36.7, 32.2 and 32.1 kJ/mol for 1, 2 and 3 m/s, respectively. This study provides information for future works on design, optimization and numerical simulation models in convective dryers for standard mango stone pieces according to industrial drying conditions.
Determination of the drying rate and effective diffusivity coefficients during convective drying of two-phase olive mill waste at rotary dryers drying conditions for their application
(ELSEVIER, 2020-06) Gómez-de la Cruz, Francisco J; Palomar-Carnicero, José M.; Hernández-Escobedo, Quetzalcoatl; Cruz-Peragón, Fernando
Secondary extraction factories in the oil olive production are subjected to high pressures each year due to the treatment of large quantities of olive mill wastes. In return, this sector achieves a biomass by-product and olive pomace oil. Furthermore, these facilities remove a serious environmental problem. To help improve and optimize the drying process of these wastes, we have carried out a study of mass transfer in a convective dryer using the drying conditions in rotary dryers. A design of experiments based on a central composite design in two dimensions, drying air temperature (between 100ºC and 425ºC) and drying air velocity (between 1 m/s and 7 m/s), was used to determine the drying rate and effective diffusivity coefficients. These variables were calculated from the experimental data obtained in isothermal drying test. Polynomial surface models, obtained by the linear least-squares fitting method, allowed to calculate these variables as a function of other such as drying air temperature, drying air velocity and moisture ratio. Drying rate and effective diffusivity values were found between 0.00001915 and 0.028 kgwater/kgsolid·s and 1.917·10-8 and 10.02·10-8 m2/s, respectively. These parameters will contribute to solve the heat and mass transfer phenomena in rotary dryers.
Energy and exergy analysis during drying in rotary dryers from Finite Control Volumes: applications to the drying of olive stone
(ELSEVIER, 2022-01) Gómez-de la Cruz, Francisco J.; Palomar-Torres, Amalia; Palomar-Carnicero, José M.; Cruz-Peragón, Fernando
Nowadays, the design, control and development of rotary dryers are based on the study of the complete equipment. Rotary dryers are treated as a black box where only inlet and outlet parameters are known. This implies the need to know the main interactions of mass, energy and exergy throughout the trommel to help improve the drying process. In this paper, we carried out an analysis of energy and exergy during drying of olive stone from finites control volumes in an experimental rotary dryer. Mass, energy and exergy balances are applied to each control volume in the drying air. The design of experiments is based on three initial drying air temperatures (210ºC, 180ºC and 150ºC) and three drying air flows (576 kg/h, 425 kg/h and 280 kg/h), with a by-product mass flow of 40 kg/h and a rotational speed of 5.5 rpm. The results indicated that olive stone moisture content was reduced to less than half in the first third of the trommel where a big thermal shock is produced due to the interaction between the by-product and the drying air flow at high moisture contents and high temperatures, respectively. This fact led to the highest exergy destruction values, thereby diminishing the flow exergies for the following control volumes. Heat losses were considerable in all equipment, especially in the first two control volumes. Furthermore, drying process was analyzed from the energetic, exergetic and drying efficiencies and the unit energy consumption.
Experimental studies on mass transfer during convective drying of spent coffee grounds generated in the soluble coffee industry
(SPRINGER, 2021-07) Gómez-de la Cruz, Francisco J.; Palomar-Carnicero, José M.; Hernández-Escobedo, Quetzalcoatl; Cruz-Peragón, Fernando
Drying is a very important stage in the treatment of spent coffee grounds destined to biofuels production. The mass transfer during the convective drying of spent coffee grounds generated in the soluble coffee industry (SCG-SCI) is analyzed. An experimental design from sixteen isothermal drying experiments for different sample thicknesses (5mm, 10mm, 15mm and 20mm) and drying air temperatures (100ºC, 150ºC, 200ºC and 250ºC) using a drying air velocity of 1m/s was proposed. Drying times, drying rates and effective diffusivity coefficients were obtained. Drying curves were fitted with the main mathematical model proposed in the literature and drying rates were studied from the moisture ratio and the drying air temperature. Constant and time-dependence effective diffusivity were evaluated using polynomial surface models. Drying times range between 18 minutes (test at 5 mm and 250ºC) and 3 hours (test at 20 mm and 100ºC). Drying rate and effective diffusivity values were found between 0.0000226 and 0.001722 s-1 and 1.79·10-9 and 29.1·10-9 m2/s, respectively. The main differences between these experiments and those carried out by the same authors about the drying of spent coffee grounds obtained in the services sector (SCG-SS) were studied and analyzed.
Methodology improvements to simulate performance and emissions of engine transient cycles from stationary operating modes: A case study applied to biofuels
(Elsevier, 2022-03-15) Cruz-Peragón, Fernando; Torres-Jiménez, Eloísa; Lešnik, Luka; Armas, Octavio
In the present study engine/vehicle responses from a standardized transient test cycle are estimated using 13 stationary operating regimes following a previously developed methodology. The main advantage of the methodology tested is that allows obtaining an estimation of transient parameters in a stationary test bench, which requirements are much less demanding than those of the transient test bench. The objectives are: in one hand, to demonstrate that the methodology correctly estimates engine responses regardless of the fuel tested, as it is proposed in a previous paper and, on the other hand, to improve the methodology and the accuracy of the estimated parameters. The fuels tested are renewable fuels from different raw materials (biodiesel from rapeseed, sunflower, and soybean), and diesel fuel as the reference. Biodiesels were tested neat and blended (30% v/v) with diesel fuel. The engine is a common-rail light-duty one, and the standardized testing procedure used to illustrate the implementation of the methodology is the New European Driving Cycle (NEDC). Two design of experiments (DoE) of 13 runs each were analyzed. One of the DoE tested was proposed for characterizing the NEDC, referred as to CTDoE design, while the other one is a five-level fractional factorial design (FFDoE) that adequately matches the optimality criteria of orthogonality, D-optimal criterion, rotatability, and space-filling. The original methodology was improved by the implementation of a new fitting function that simulates the cold start effect over the engine parameters and by a new definition of the boundary in the [n,M] domain. These improvements showed significantly higher accuracy of the estimated engine parameters obtained, both instantaneous and accumulated, respect to the original methodology. The results obtained based on the application of the FFDoE design support the feasibility of the methodology tested. Engine performance and regulated emissions responses, such as intake air and fuel mass flow rate, thermomechanical exergy rate, exhaust gas residual heat rate, total hydrocarbons (THC), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM) emissions from a transient test were instantaneously and cumulatively predicted with high accuracy using the engine responses from 13 steady-state operating modes.
Optimal design of a hybrid Ground Source Heat Pump for an official building with thermal load imbalance and limited space for the Ground Heat Exchanger.
(ELSEVIER, 2022-08) Cruz-Peragón, Fernando; Gómez-de la Cruz, Francisco J.; Palomar-Carnicero, José M.; López-García, Rafael
This work presents the optimal design of a hybrid ground source heat pump (GSHP), taking into account thermal imbalance and space limitation for the ground heat exchanger field (GHE), applied to an official building. Once the building loads are calculated and devices selected, experiments carried out from a single vertical borehole obtain the ground thermal characteristics, including a local short-term period function (STGF). From them, the Finite Line-Source (FLS) model simulates the GHE behavior, from decomposing the ground thermal loads in hourly linear steps for 50 years. A set of input variables, such as geometric configuration data of boreholes field, and additional terms associated with this hybrid operation, must be provided to the model. For optimization purposes, a design of experiments (DoE) considers the thermal ground characteristics and input factors, providing both energy savings and the internal rate of return as outputs (objective functions). Pareto’s optimal solutions method provides the selected case, considering a compromise between economic and environmental benefits. It has been established for 18 boreholes (rectangular disposition) of 120 meters deep, providing a 33.12% energy saving and an internal rate of return of 3.9%, also showing 89% of the total building load supported by the GHE.
Prediction of emissions and performance from transient driving cycles using stationary conditions: Study of advanced biofuels under the ETC test
(Elsevier, 2023-01) Soto, Felipe; Dorado-Vicente, Rubén; Torres-Jiménez, Eloísa; Cruz-Peragón, Fernando
This paper applies and improves a methodology for estimating engine responses from transient cycles using steady conditions according to a Design of Experiments (DoE). The fuels tested are diesel-farnesane, biodiesel from sugarcane, and diesel fuel S50. A common-rail engine and the European Transient Cycle (ETC) are considered. Two DoEs of 13 runs each were analysed: the 13 modes of the European Stationary Cycle (ESCDoE) and a 5-level Fractional Factorial Design (FFDoE). The mathematical transformation of the engine working region and the experimental data approximation were improved using chord length parameterization and tensor product surfaces, respectively. Both DoEs provide an instantaneous approximation of engine performance responses of high accuracy. However, in general, better results are obtained using the FFDoE (R2 > 0.92, but R2 > 0.84 for exergy rate) compared to the ESCDoE (R2 > 0.87, and R2 > 0.53 for exergy rate). The FFDoE is the most appropriate design for the instantaneous prediction of THC and NOx regulated emissions (R2 > 0.91) as well as for its specific (accumulated) emissions (relative error e < 11%). However, worse results are obtained for CO emissions prediction (R2 > 0.7 and e < 19.1%).
Why we should invest further in the development of internal combustion engines for road applications
(EDP SCIENCES S A, 2020-07-02) Lešnik, Luka; Kegl, Breda; Torres-Jiménez, Eloísa; Cruz-Peragón, Fernando
The majority of on-road vehicles today are powered by internal combustion engines, which are, in most cases, burning petroleum-derived liquid fuels mixed with bio-components. The power to weight ratio of internal combustion engines combined with the high energy content of conventional fuels, which can be refilled easily in matter of minutes, makes them ideal for all kinds of road transportation. Since the introduction of EURO emissions norms, the emissions from the Transport sector in the European Union have undergone significant reduction. There are several alternatives to fossil fuels with similar properties, which can replace their usage in the Transport sector. The main focus of research in recent decades has been on biofuels, which can be produced from several sources. The production of biofuels is usually energy more intensive than production of fossil fuels, but their usage can contribute to emission reduction in the Transport sector. In recent years, a lot of effort was also put into promotion of electric vehicles as zero emissions vehicles. This statement should be reconsidered, since the greenhouse impact of electrical vehicles is not negligible. Conversely, in some cases, an electrical vehicle can have an even higher emission impact than modern vehicles with sophisticated internal combustion engines. This is characteristic for countries where the majority of the electricity is produced in coal power plants. With the decrease of greenhouse gas emissions in the Electricity Production sector, and with the increase of battery capacity, the role of electric vehicles in the Transport sector will probably increase. Despite significant research and financial investments in electric vehicles development, the transport sector in near future will be mostly powered by internal combustion engines and petroleum-derived liquid fuels. The amount of pollution from transport sector will be further regulated with stricter emission norms combined with smaller amount of alternative fuel usage.

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Examinando Departamento de Ingeniería Mecánica y Minera por Autor "Cruz-Peragón, Fernando"