Papers by Julian Blanco Galvez
Descontaminación de aguas residuales mediante fotocatálisis solar
Ingenieria Quimica, 1993
Tecnología de fotocatálisis solar: utilización de la radiación solar para el tratamiento de contaminantes industriales
lógicas) con sistemas térmicos solares se está aprovechando para desarrollar y establecer sistema... more lógicas) con sistemas térmicos solares se está aprovechando para desarrollar y establecer sistemas eficaces, capaces de destruir compuestos tóxicos procedentes de residuos industriales mediante la radiación solar. El proceso, denominado Detoxificación mediante Fotocatálisis Solar, está siendo estudiado a nivel pre-industrial en estrecha colaboración con algunos de los científicos europeos más relevantes en este campo. Una de las características, generalmente olvidada, que mejor define la sociedad actual en lo que se entiende por países desarrollados es la producción de residuos. Prácticamente no hay actividad humana alguna, que no genere residuos existiendo además una relación directa entre la cantidad de residuos generados y el nivel de vida de una sociedad o país. Según datos aportados por el Worldwatch Institute, fundación que anualmente publica el informe «El Estado de la Tierra», cada año los países miembros de la Unidad Europea producen unos 2200 millones de Tm. de residuos (unos 18 kg. por persona y día). De esta cantidad unos 150 millones de Tm. son catalogados como residuos industriales y de estos a su vez, entre 20 y 30 millones de Tm. son residuos catalogados como tóxicos y peligrosos. En Estados Unidos esta cantidad se eleva a 275 millones de Tm. al año según datos de la Agencia de Protección Medioambiental. Son estos últimos residuos los más preocupantes y problemáticos ya que muchas veces literalmente no se sabe qué hacer con ellos. Gran parte de ellos son actualmente directamente arrojados a cauces públicos a través de los efluentes de aguas residuales industriales, con la consiguiente contaminación de los mismos. Otra parte importante va a vertederos en los cuales en el mejor de los casos simplemente se almacena el problema cuando, no se producen fil-
Experimental results of a new hybrid solar/gas multi-effect distillation system
Energy Procedia, 2015
Mediterranean (South of Europe) and MENA regions are increasingly facing the lack of fresh water ... more Mediterranean (South of Europe) and MENA regions are increasingly facing the lack of fresh water supplies. They have high solar radiation levels, which make them good candidates for the development and installation of concentrating solar power (CSP) plants. Therefore, cogeneration of electricity and fresh water using CSP with desalination plants (CSP+D) can be proposed as a sustainable option for these regions. The aim of this work is to find the most suitable CSP+D configurations (including the power cycle refrigeration technology) in Mediterranean and MENA regions. For this purpose, a comparative techno-economic analysis of CSP+D plants that considers several integrations of the Multi-Effect Distillation (MED) process together with the independent freshwater and power production by connecting a Reverse Osmosis (RO) system has been carried out. The three conventional cooling methods for power cycles have been taken into account: dry cooling, once-through and wet cooling.
PSA-MED performance prediction: computational model and its experimental validation
Multi-effect distillation (MED) processes have acquired a high interest in the last years, especi... more Multi-effect distillation (MED) processes have acquired a high interest in the last years, especially to be coupled with a solar thermal energy source. To get the largest efficiency from this process in order to reduce its thermal consumption, it is necessary to understand in detail the process elements to improve future designs and to predict the performance over a wide range of operating conditions. This work presents a simulation program to simulate the performance of a pilot MED plant located at the Plataforma Solar de Almeria using hot water as the thermal energy source and its validation using experimental data obtained from the operation of the plant. To solve this model, parametric equations that represent some of the variables of the model have been obtained, carrying out a method of design of experiment (DoE) based on a 3k factorial design with a total of 81 experiments. The validation of the model has been performed by the assessment of the relative error between measured...
International Journal of Environment and Pollution, 2006
Homogeneous photocatalysis by photo-Fenton processes has been applied to the degradation of six w... more Homogeneous photocatalysis by photo-Fenton processes has been applied to the degradation of six water-soluble pesticides (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol), considered priority substances by the European Union Water Framework Directive (Directive 2000/60/EC). All tests were performed in a 35-L solar pilot plant with compound parabolic collectors (CPCs) under natural sunlight. The initial concentration tested for all the compounds was 50 mg/L except for those less soluble in water. Two different concentrations of iron were tested, 2 mg/L and 1 mM. All pesticides were successfully degraded and substantially mineralised. Total dechlorination was clearly attained more quickly than 90% of mineralisation in all cases. Several operating parameters, treatment time, hydrogen peroxide consumption and iron concentration, involved in the degradation of the parent compounds and their mineralisation are discussed.
Characterisation of the coupling of multi-effect distillation plants to concentrating solar power plants
Energy, 2015
ABSTRACT The aim of this work is to prove that the integration of a Multi-Effect Distillation (ME... more ABSTRACT The aim of this work is to prove that the integration of a Multi-Effect Distillation (MED) into a Concentrating Solar Power Plant (CSP) can be more competitive, under certain conditions, than the independent freshwater and power production by connecting a Reverse Osmosis (RO) unit to a CSP plant. For this purpose, different CSP+MED configurations using the steam from the turbine as the energy source of the desalination process have been evaluated and compared to the simple combination of a CSP plant connected to a RO plant. A sensitivity analysis has been carried out for two regions, MENA and the South of Europe, by varying different parameters of the whole system (like the specific electric consumption and the exhaust vapor temperature) and calculating in each case the overall thermodynamic efficiency of the combined system for the same amount of electricity and desalinated water. This analysis has been performed for the three types of refrigeration system (dry cooling, once-through and evaporative cooling) and the results have been discussed in detail. The thermodynamic evaluation has been complemented with an economic analysis for a study case taking two locations representative of each region and the best configurations have been selected.
Photocatalysis
Solar Energy, 2004
Photocatalytic degradation of industrial residual waters
Solar Energy, 1996
Solar photocatalytic water mineralization using the interaction between ultraviolet radiation and... more Solar photocatalytic water mineralization using the interaction between ultraviolet radiation and titanium dioxide (TiO2) has a strong potential for the destruction of toxic organics in water, as widely demonstrated in recent years. Testing of several real waste-water ...
Desalination and Water Treatment, 2011
Potable water supply by desalination systems has a significant role in today's developing world. ... more Potable water supply by desalination systems has a significant role in today's developing world. Multi-effect distillation (MED) is a progressing, low cost and easy operating system to produce drinking and pure water for both social and industrial applications. It is very important to understand in detail the process elements in order to determine the effects of the important design and operating variables on the parameters controlling the performance of the plant. A model is developed for the MED plant located at the Plataforma Solar de Almería (PSA), in the southeast of Spain. It is a vertical-arrangement forward-feed MED plant with pre-heaters, which uses hot water as the thermal energy source. The model has been developed dividing the MED plant into four blocks: the heater (consisting of the first effect), the evaporators (consisting of effects 2 to N), the pre-heaters (for effects 1 to N -1) and the condenser (after effect N). To solve the model, a parameterization of the overall heat transfer coefficient of the four blocks has been carried out with experimental data for a wide range of operation, based on correlations found by other authors for similar plants. The adjustments were good for all the components with the exception of the condenser, which seems to behave differently than in other cases reported in the literature.
Desalination and Water Treatment, 2011
Freshwater shortage difficulties make it necessary to find new sources of supply. Nowadays desali... more Freshwater shortage difficulties make it necessary to find new sources of supply. Nowadays desalination is the solution adopted in many countries to solve this problem. All around the planet, regions with lack of freshwater match up with those with large amounts of available solar radiation. Therefore, solar desalination can be a suitable and sustainable option to tackle the water scarcity problems in those particular areas, especially in the coastal ones. Membrane distillation (MD) is a thermal membrane technology developed since late 60's which uses low exergy heat to drive a separation process in aqueous solutions. One of its applications is desalination where thanks to its separation principle, very high distillate quality can be obtained. MD is a thermally driven process that differs from other membrane technologies in that its driving force, rather than the total pressure, is the difference in water vapour pressure across the membrane, caused in turn by a temperature difference between the cold and the hot side of it. In comparison with other membrane-based desalination processes like reverse osmosis (RO), MD shows very high rejection rates and much lower operational pressures, also the nature of MD membranes (larger pore sizes than RO) makes them much less sensitive to fouling. Compared to conventional thermal desalination processes like MSF or MED, MD is less demanding regarding vapor space and building material's quality [1] leading to potential lower construction costs. Amongst its advantages, its low operating temperatures (ranging between 60-90°C [2]) make possible the use of low-grade heat, the kind of energy delivered by static solar collectors, as the only thermal supply. This, jointly with its low operational pressure and small footprint, make solar membrane distillation (SMD) in principle, a promising technology. Despite these advantages, SMD has been developed to a lesser extent, compared with other solar desalination technologies like PV-driven RO or solar stills, and although many encouraging laboratory experiences can be found in literature, large-scaling and module design is still an issue. It is precisely because of this preliminary state MD is in, that very preliminary, low energy efficiency and not commercial available MD prototypes are still found. In MD there is still a trade-off between efficiency (heat consumption) and production (distillate per square meter of membrane), as a result very high specific distillate fluxes can be attained (up to 80 kg h -1 m -2 of membrane [3]) but heat losses (mainly trough the membrane by conduction) are still substantial. Under the framework of an European project (MEDESOL: Seawater Desalination by Innovative Solar Powered Membrane Distillation) which main objective was to develop a stand-alone desalination system based on multi stage MD to supply decentralized rural areas [4], the status and future possibilities of currently developed MD have been evaluated. This paper presents the results obtained from the experiments realized with two different pre-commercial MD modules, coupled to a solar field comprised of static collectors. Both modules were tested in the same facility under the same conditions, in order to make a reliable comparison between them. Data on energy efficiency, production ratios and operational issues will be shown.
Desalination and Water Treatment, 2010
This paper deals with a project entitled "Seawater Desalination by Innovative Solar-Powered Membr... more This paper deals with a project entitled "Seawater Desalination by Innovative Solar-Powered Membrane-Distillation System", MEDESOL (FP6-2005-Global-4, FP6-036986). The main project objective is the development and experimental assessment of solar multi-stage MD concept in order to obtain a high-effi ciency and cost-effective system for stand-alone seawater desalination. This concept is based on the use of some MD modules connected with a particular design arrangement to minimize both, main and auxiliary energy consumptions. The selection of the system confi guration is based on a generic membrane distillation module. This paper selects the confi guration of the MD system among different candidate designs, set the prospects of solar MD technology as function of available MD modules and assess the infl uence on system effi ciency of main operational parameters of an individual module: temperature gradient across the membranes and maximum working temperature.
Desalination and Water Treatment, 2013
In this work a steady-state model is developed of an MED plant. Its development and validation ha... more In this work a steady-state model is developed of an MED plant. Its development and validation have been carried out by experimental data obtained from an MED pilot plant located at the Plataforma Solar de Almerı ´a (PSA), in the southeast of Spain. It is a vertical arrangement forward-feed MED plant with preheaters, which uses hot water as the thermal energy source. In order to run the model, a series of parametric equations have been determined for the following variables: the overall heat transfer coefficient for the first effect (U h ), the overall heat transfer coefficient for the preheaters (U p (i)), the vapor temperature inside the first effect (T v (1)), and the cooling seawater outlet temperature (T cwout ). They have been obtained from a three-level factorial experimental design (3 k ), performing a total of 81 experiments (3 4 ). The results obtained showed a good fit to the estimated models for the response variables.
Desalination and Water Treatment, 2013
The development of society is strongly dependent on water and electricity. There is an increasing... more The development of society is strongly dependent on water and electricity. There is an increasing water and energy demand driven by population growth and rising industrial and agricultural production. The combination of concentrated solar power (CSP) and desalination processes has a huge potential for producing both energy and water in arid regions suffering from fresh water scarcity and facing the current energy challenge. One of the regions is Middle East and North Africa (MENA), where plans are currently under discussion to make possible large CSP plants developments. The integration of desalination (CSP+D) into solar power plants could make CSP technology even more attractive in such regions. The focus of this study is thermodynamic characterization and an economic evaluation of different configurations for coupling parabolic trough solar power plants and desalination facilities at a MENA location in Egypt chosen as reference for its Southern coast (Port Safaga). The desalination technologies considered for the combination with parabolic trough concentrating solar power plants (PT-CSP), are low temperature multi-effect distillation (LT-MED) and reverse osmosis (RO). Moreover, an additional concept of LT-MED has been evaluated: a LT-MED powered by the steam obtained from a thermal vapor compressor (TVC). In this case, unlike the conventional thermal vapor compression process (TVC-MED), the entrained vapor to be used in the ejector comes from the exhaust steam from the low pressure (LP) turbine instead of an effect of the MED unit. In order to optimize this latter concept (LT-MED-TVC), different configuration schemes have been studied. When thermodynamic efficiencies and costs are analyzed comparing the two more efficient configurations (PT-CSP/RO and PT-CSP/LT-MED), considering 58˚C/0.18 bar of exhaust turbine steam conditions and 5.5 kWh/m 3 of RO power requirements, initial results are very similar.
Desalination, 2008
From 2002 to 2006, a combined R&D project named AQUASOL has been carried out at the facilities of... more From 2002 to 2006, a combined R&D project named AQUASOL has been carried out at the facilities of the Plataforma Solar de Almería (Spain). Main objective of this project has been the development of a hybrid solargas desalination system based on multi-effect distillation process that meets at the same time the requirements of low-cost, high efficiency and zero discharge. The final AQUASOL plant, implemented at the Plataforma Solar de Almería for its evaluation under real meteorological conditions, is composed of: (i) a 14-cell forward-feed vertically-stacked MED unit, (ii) a 500 m 2 stationary CPC (compound parabolic concentrator) solar collector field, (iii) a 24 m 3 thermal storage system based on water, (iv) a new advanced prototype of double-effect absorption (LiBr-H 2 O) heat pump, (v) a smoketube gas boiler to guarantee 24-h operation. This paper shows the first experimental results obtained during the test campaign of the project. The performance ratio reached by the distillation plant in different operational modes is evaluated, as well as the issues related with the operation of the subsystems that compose the AQUASOL desalination system.
Treatment of chlorinated solvents by TiO2 photocatalysis and photo-Fenton: influence of operating conditions in a solar pilot plant
Chemosphere, 2005
Titanium dioxide photocatalysis (using 20 0mg l(-1) of TiO2), under aerobic and anaerobic conditi... more Titanium dioxide photocatalysis (using 20 0mg l(-1) of TiO2), under aerobic and anaerobic conditions, and photo-Fenton (2 and 56 mg l(-1) iron) were applied to the treatment of different NBCS (non-biodegradable chlorinated solvents), such as dichloroethane, dichloromethane and trichloromethane dissolved in water at 50 mg l(-1). All the tests were performed in a 35-l solar pilot plant with compound parabolic collectors (CPCs) under natural illumination. The two solar treatments were compared with attention to chloride release and TOC mineralisation, as the main parameters. Photo-Fenton was found to be the more appropriate treatment for these compounds, assuming volatilisation as a drawback of photocatalytic degradation of NBCS dissolved in water. In this context, several operating parameters related to NBCS degradation, e.g., treatment time, temperature, hydrogen peroxide consumption and volatility of parent compounds are discussed. The correct choice of operating conditions can very often diminish the problem of volatilisation during treatment.
Applied Thermal Engineering, 2013
Different alternatives for the effective integration of desalination technologies in the cooling ... more Different alternatives for the effective integration of desalination technologies in the cooling of concentrating solar power (CSP) plants in the Mediterranean area are discussed and evaluated. Two cases are considered where a low temperature multi-effect distillation (LT-MED) plant is integrated into a CSP plant replacing the condenser of the power cycle. In one case, a LT-MED plant is fed by steam at the outlet of the turbine expanded to 70 C. In the other case a LT-MED is fed by the steam obtained from a thermal vapour compressor (TVC) which uses the exhaust steam of the CSP plant (at 37 C, 0.063 bar) together with some from the high pressure turbine extraction (17 bar). The two cases are compared with that of a reverse osmosis (RO) unit powered by the electricity produced by the CSP plant. In this case, two different wet cooling technologies, once-through and evaporative water cooling, and a dry air cooling are considered for the CSP plant. Thermodynamic simulations are presented for all cases, together with an economic analysis.
Incorporation of solar energy in water technologies: solar desalination for the provision of water in remote areas
TECNIA, 2017
El siglo XX ha traído un desarrollo sin precedentes en la historia de la humanidad con avances im... more El siglo XX ha traído un desarrollo sin precedentes en la historia de la humanidad con avances impresionantes en todas las disciplinas de la ciencia y de la técnica. Sin embargo dichos avances no han sido algo gratuito, sino que han tenido un precio que no sería descabellado considerar que, bajo determinados prismas, ha sido excesivo. Durante los últimos 100 años, la población humana en la Tierra se ha multiplicado por un factor de 4 (pasando de 1.600 millones de personas en 1.900 a los más de 6.000 millones de la actualidad). Sin embargo el consumo de agua se ha multiplicado por 9 en el mismo periodo y el consumo de energía por 16, y ello con una degradación asociada del medio ambiente y los recursos naturales, en general, muy significativa.
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Papers by Julian Blanco Galvez