Regeneración de carbones activados mediante tratamientos térmico / gasificación y oxidación húmeda. Aplicación en ciclos de adsorción

La presente Tesis Doctoral tiene por objeto el estudio de la regeneración de carbones activados empleados para la adsorción de paranitrofenol, una vez éstos han sido saturados. Previo a su saturación, se estudió el equilibrio y la cinética de adsorción (en batch y en columna). En cuanto a los procesos de regeneración, la experimentación se dividió en dos bloques: a) experiencias de regeneración térmica, mediante termogravimetría en atmósfera inerte (estudiando los diferentes eventos térmicos y asociándolos con la naturaleza del proceso de desorción implicado), y regeneración en uno o dos reactores (con y sin adición de agente activante y con y sin craqueo de los gases generados), y b) oxidación húmeda. En ambos casos se buscó la optimización del proceso mediante la variación de las condiciones experimentales (temperatura, presión, empleo de agente oxidante y rampa de calentamiento, entre otras). La búsqueda de las condiciones más interesantes fue realizada atendiendo a criterios de recuperación de porosidad, ahorro en costes y degradación de las especies desorbidas hacia especies menos tóxicas. Los resultados obtenidos mostraron el buen comportamiento de la regeneración térmica empleada de forma conjunta con la activación con dióxido de carbono y vapor de agua; especialmente en éste último caso, pudo verificarse el uso en ciclos de adsorción/desorción del adsorbente, llegando incluso a mejorar las características del carbón original. La oxidación húmeda también resultó interesante, especialmente para las mayores presiones y temperaturas empleadas, mostrando una ligera disminución de las características de porosidad para un número creciente de ciclos.The aim of the present Doctoral Thesis is the study of the regeneration of activated carbons which have been used for the adsorption of paranitrophenol. Before their saturation, the study of the corresponding equilibrium adsorption and kinetics was studied (in batch and column continuous mode). Regarding the adsorbent regeneration processes, the experimentation was divided into two main sections: a) thermal regeneration, by means of thermogravimetry under inert atmosphere (analyzing the different thermal events and relating them to the nature of the type of adsorption process involved), and by means of heating in one or two reactors (with or without the addition of an activant agent, and with or without subsequent cracking of the gases released), and b) wet oxygen oxidation. In both cases, the influence of characteristical experimental conditions were studied (temperature, pressure, use of oxidant agent, and heating rate, among others). The search of optimal conditions was based on the carbon porosity regain, costs and degradation of toxic desorbed species. The results obtained indicated the good behaviour of thermal regeneration in conjunction with carbon dioxide or steam activation; especially in the latter case the use of the carbon in adsorption/desorption cycles, even achieving porosity characteristics which were better than those of the original carbon. Wet oxidation processes were also very interesting, especially when high temperatures and pressures were used. The results also showed an slight decrease on the porosity development of the carbons as the number of cycles was increased

Regeneración de carbones activados mediante tratamientos térmico / gasificación y oxidación húmeda. Aplicación en ciclos de adsorción

La presente Tesis Doctoral tiene por objeto el estudio de la regeneración de carbones activados empleados para la adsorción de paranitrofenol, una vez éstos han sido saturados. Previo a su saturación, se estudió el equilibrio y la cinética de adsorción (en batch y en columna). En cuanto a los procesos de regeneración, la experimentación se dividió en dos bloques: a) experiencias de regeneración térmica, mediante termogravimetría en atmósfera inerte (estudiando los diferentes eventos térmicos y asociándolos con la naturaleza del proceso de desorción implicado), y regeneración en uno o dos reactores (con y sin adición de agente activante y con y sin craqueo de los gases generados), y b) oxidación húmeda. En ambos casos se buscó la optimización del proceso mediante la variación de las condiciones experimentales (temperatura, presión, empleo de agente oxidante y rampa de calentamiento, entre otras). La búsqueda de las condiciones más interesantes fue realizada atendiendo a criterios de recuperación de porosidad, ahorro en costes y degradación de las especies desorbidas hacia especies menos tóxicas. Los resultados obtenidos mostraron el buen comportamiento de la regeneración térmica empleada de forma conjunta con la activación con dióxido de carbono y vapor de agua; especialmente en éste último caso, pudo verificarse el uso en ciclos de adsorción/desorción del adsorbente, llegando incluso a mejorar las características del carbón original. La oxidación húmeda también resultó interesante, especialmente para las mayores presiones y temperaturas empleadas, mostrando una ligera disminución de las características de porosidad para un número creciente de ciclos.The aim of the present Doctoral Thesis is the study of the regeneration of activated carbons which have been used for the adsorption of paranitrophenol. Before their saturation, the study of the corresponding equilibrium adsorption and kinetics was studied (in batch and column continuous mode). Regarding the adsorbent regeneration processes, the experimentation was divided into two main sections: a) thermal regeneration, by means of thermogravimetry under inert atmosphere (analyzing the different thermal events and relating them to the nature of the type of adsorption process involved), and by means of heating in one or two reactors (with or without the addition of an activant agent, and with or without subsequent cracking of the gases released), and b) wet oxygen oxidation. In both cases, the influence of characteristical experimental conditions were studied (temperature, pressure, use of oxidant agent, and heating rate, among others). The search of optimal conditions was based on the carbon porosity regain, costs and degradation of toxic desorbed species. The results obtained indicated the good behaviour of thermal regeneration in conjunction with carbon dioxide or steam activation; especially in the latter case the use of the carbon in adsorption/desorption cycles, even achieving porosity characteristics which were better than those of the original carbon. Wet oxidation processes were also very interesting, especially when high temperatures and pressures were used. The results also showed an slight decrease on the porosity development of the carbons as the number of cycles was increased

Implementación de PBL en la asignatura de termodinámica técnica. Diseño y evaluación

El uso de la metodología de Aprendizaje Basado en Problemas (APB o PBL, Problem Based Learning) ha mostrado ser muy efectiva para fomentar el proceso de Enseñanza-Aprendizaje en las enseñanzas universitarias. En el marco de Bolonia, dicha estrategia no sólo favorece la adquisición de los conocimientos y destrezas específicos de una materia, sino que permite al alumno adquirir competencias transversales, como el trabajo en grupo, la búsqueda de recursos, o la toma de decisiones. En este trabajo se describe el diseño de una actividad de ABP, contextualizado en la asignatura de Termodinámica Técnica, de los grados de Ingeniería (tres especialidades: Mecánica, Eléctrica, y Electrónica y Automática) de la Escuela de Ingenierías Industriales de Extremadura. La actividad, realizada en grupos de cuatro estudiantes, consistió en la resolución de uno o varios problemas de la materia, previa designación de los roles que cada estudiante desempeñaría en el grupo. Finalmente se describe el sistema de evaluación que permitió diferenciar los resultados de aprendizaje específico, y los de la metodología en sí

Valorización como adsorbente del carbón activado procedente de la Central Nuclear de Almaraz

El presente trabajo se enmarca dentro de las líneas de investigación que se desarrollan en el grupo de investigación GAIRBER (Grupo de Aprovechamiento Integral de Residuos Biomásicos y Energías Renovables) de la Universidad de Extremadura (UEX). El inicio de este trabajo surge a raíz del convenio que tiene la Central Nuclear deAlmaraz (CNA) con la UEX, centrado en el aprovechamiento del carbón activado (CA) residual, el cual ha sido diseñado para su empleo en los filtros de retención de materiales radiactivos, fundamentalmente en la forma de 131I. A pesar de que no se haya requerido su uso, al no haber sido expuesto a gases radiactivos, dicho carbón debe ser reemplazado periódicamente, debido a la modificación de sus características texturales y/o superficiales por el envejecimiento. En este sentido, el grupo de investigación está estudiando múltiples opciones para su aprovechamiento. Entre ellas, se contempla su aplicación como adsorbente. En este estudio, se ha utilizado el CA de la central sin tratar y tratado, tanto mediante un ciclo de lavado, como por oxidación del mismo, con el objeto de disponer de adsorbentes que presenten diferencias superficiales, las cuales condicionarán la eficacia de su posterior aplicación. En los mencionados carbones se ha llevado a cabo la adsorción de un tinte, Azul de Metileno.Los autores agradecen a la Central Nuclear de Almaraz-Trillo permitir este tipo de investigació

Hydrothermal carbonization: modeling, final properties design and applications: a review

La investigación activa sobre la carbonización hidrotermal de la biomasa (HTC) sigue demostrando sus ventajas sobre otros procesos termoquímicos, en particular los interesantes beneficios que se asocian a los productos sólidos carbonosos, llamados hidrocarburos (HC). Las esferas de aplicación del HC van desde el biocombustible hasta el material poroso dopado para la adsorción, el almacenamiento de energía y la catálisis. Al mismo tiempo, se han realizado intensas investigaciones para dilucidar mejor los mecanismos y la cinética del proceso, y la forma en que las variables experimentales (temperatura, tiempo, carga de biomasa, composición de la materia prima, así como sus interacciones) afectan a la distribución entre las fases y a su composición. En este examen se analiza el estado de la técnica en materia de HTC, principalmente en lo que respecta al efecto de las variables en el proceso, la cinética asociada y las características de la fase sólida (HC), así como algunas de las aplicaciones más estudiadas hasta ahora. El foco de atención se centra en las investigaciones realizadas en los últimos cinco años sobre estos temas.Active research on biomass hydrothermal carbonization (HTC) continues to demonstrate its advantages over other thermochemical processes, in particular the interesting benefits that are associated with carbonaceous solid products, called hydrochar (HC). The areas of applications of HC range from biofuel to doped porous material for adsorption, energy storage, and catalysis. At the same time, intensive research has been aimed at better elucidating the process mechanisms and kinetics, and how the experimental variables (temperature, time, biomass load, feedstock composition, as well as their interactions) affect the distribution between phases and their composition. This review provides an analysis of the state of the art on HTC, mainly with regard to the effect of variables on the process, the associated kinetics, and the characteristics of the solid phase (HC), as well as some of the more studied applications so far. The focus is on research made over the last five years on these topics.• Junta de Extremadura. Proyecto GR15034 • Ministerio de Economía y Competitividad. Proyectos CTM2014-55998-R (I+D+i), CTM2016-75937-R • USDA-Agricultural Research Service National Program 212peerReviewe

Dependence of the microporosity of activated carbons on the lignocellulosic composition of the precursors

Se preparó una serie de carbones activados mediante gasificación física con vapor de vapor en condiciones experimentales idénticas para comparar el desarrollo de poros de los caracteres de poda de almendros y los carbonos activados de cáscara de nuez. Los resultados obtenidos mostraron que la gasificación por vapor produce carbones microporosos en ambos casos, y el aumento de la temperatura provoca un aumento de los volúmenes de poros de los carbones activados, hasta un cierto grado de combustión. Este efecto fue más marcado para la cáscara de nuez, que dio lugar a carbones activados con valores de superficie aparentes de hasta 1434 m2. g-1. Además, se encontró un ligero ensanchamiento de la porosidad en bajos grados de combustión. Esta ampliación de poros fue más marcada en el caso de los carbones activados de la poda de almendros, que también tienen un alto volumen de macroporos. Se encontró que las propiedades lignocelulósicas y de porosidad de las materias primas pueden causar este comportamiento diferente hacia los procesos de activación.A series of activated carbons were prepared by physical steam gasification under identical experimental conditions to compare the pore development from almond tree pruning chars and walnut shell activated carbons. The results obtained showed that steam gasification yields microporous carbons in both cases, and the rise in temperature causes an increase of the pore volumes of the activated carbons, up to a certain degree of burn-off. This effect was more marked for walnut shell, which gave rise to activated carbons with apparent surface values of up to 1434 m2.g-1. Also, a slight widening of porosity was found at low burn-off degrees. This pore widening was more marked in the case of activated carbons from almond tree pruning, which also have a high macropore volume. It was found that the lignocellulosic and porosity properties of the raw materials can cause this different behavior towards activation processes.• Ministerio de Economía y Competitividad. Proyecto CTM2016-75937-R • Gobierno de Extremadura . Ayuda GR15034 • Universidad de Extremadura. AyudapeerReviewe

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.

The Global Burden of Diseases, Injuries and Risk Factors 2017 includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. METHODS: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting

Global, regional, and national disability-adjusted life-years (DALYs) for 359 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.

How long one lives, how many years of life are spent in good and poor health, and how the population's state of health and leading causes of disability change over time all have implications for policy, planning, and provision of services. We comparatively assessed the patterns and trends of healthy life expectancy (HALE), which quantifies the number of years of life expected to be lived in good health, and the complementary measure of disability-adjusted life-years (DALYs), a composite measure of disease burden capturing both premature mortality and prevalence and severity of ill health, for 359 diseases and injuries for 195 countries and territories over the past 28 years. Methods We used data for age-specific mortality rates, years of life lost (YLLs) due to premature mortality, and years lived with disability (YLDs) from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to calculate HALE and DALYs from 1990 to 2017. We calculated HALE using age-specific mortality rates and YLDs per capita for each location, age, sex, and year. We calculated DALYs for 359 causes as the sum of YLLs and YLDs. We assessed how observed HALE and DALYs differed by country and sex from expected trends based on Socio-demographic Index (SDI). We also analysed HALE by decomposing years of life gained into years spent in good health and in poor health, between 1990 and 2017, and extra years lived by females compared with males. Findings Globally, from 1990 to 2017, life expectancy at birth increased by 7·4 years (95% uncertainty interval 7·1-7·8), from 65·6 years (65·3-65·8) in 1990 to 73·0 years (72·7-73·3) in 2017. The increase in years of life varied from 5·1 years (5·0-5·3) in high SDI countries to 12·0 years (11·3-12·8) in low SDI countries. Of the additional years of life expected at birth, 26·3% (20·1-33·1) were expected to be spent in poor health in high SDI countries compared with 11·7% (8·8-15·1) in low-middle SDI countries. HALE at birth increased by 6·3 years (5·9-6·7), from 57·0 years (54·6-59·1) in 1990 to 63·3 years (60·5-65·7) in 2017. The increase varied from 3·8 years (3·4-4·1) in high SDI countries to 10·5 years (9·8-11·2) in low SDI countries. Even larger variations in HALE than these were observed between countries, ranging from 1·0 year (0·4-1·7) in Saint Vincent and the Grenadines (62·4 years [59·9-64·7] in 1990 to 63·5 years [60·9-65·8] in 2017) to 23·7 years (21·9-25·6) in Eritrea (30·7 years [28·9-32·2] in 1990 to 54·4 years [51·5-57·1] in 2017). In most countries, the increase in HALE was smaller than the increase in overall life expectancy, indicating more years lived in poor health. In 180 of 195 countries and territories, females were expected to live longer than males in 2017, with extra years lived varying from 1·4 years (0·6-2·3) in Algeria to 11·9 years (10·9-12·9) in Ukraine. Of the extra years gained, the proportion spent in poor health varied largely across countries, with less than 20% of additional years spent in poor health in Bosnia and Herzegovina, Burundi, and Slovakia, whereas in Bahrain all the extra years were spent in poor health. In 2017, the highest estimate of HALE at birth was in Singapore for both females (75·8 years [72·4-78·7]) and males (72·6 years [69·8-75·0]) and the lowest estimates were in Central African Republic (47·0 years [43·7-50·2] for females and 42·8 years [40·1-45·6] for males). Globally, in 2017, the five leading causes of DALYs were neonatal disorders, ischaemic heart disease, stroke, lower respiratory infections, and chronic obstructive pulmonary disease. Between 1990 and 2017, age-standardised DALY rates decreased by 41·3% (38·8-43·5) for communicable diseases and by 49·8% (47·9-51·6) for neonatal disorders. For non-communicable diseases, global DALYs increased by 40·1% (36·8-43·0), although age-standardised DALY rates decreased by 18·1% (16·0-20·2)

Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Global development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017. Methods The causes of death database is composed of vital registration (VR), verbal autopsy (VA), registry, survey, police, and surveillance data. GBD 2017 added ten VA studies, 127 country-years of VR data, 502 cancer-registry country-years, and an additional surveillance country-year. Expansions of the GBD cause of death hierarchy resulted in 18 additional causes estimated for GBD 2017. Newly available data led to subnational estimates for five additional countries Ethiopia, Iran, New Zealand, Norway, and Russia. Deaths assigned International Classification of Diseases (ICD) codes for non-specific, implausible, or intermediate causes of death were reassigned to underlying causes by redistribution algorithms that were incorporated into uncertainty estimation. We used statistical modelling tools developed for GBD, including the Cause of Death Ensemble model (CODErn), to generate cause fractions and cause specific death rates for each location, year, age, and sex. Instead of using UN estimates as in previous versions, GBD 2017 independently estimated population size and fertility rate for all locations. Years of life lost (YLLs) were then calculated as the sum of each death multiplied by the standard life expectancy at each age. All rates reported here are age-standardised. Findings At the broadest grouping of causes of death (Level 1), non-communicable diseases (NC Ds) comprised the greatest fraction of deaths, contributing to 73.4% (95% uncertainty interval [UI] 72.5-74.1) of total deaths in 2017, while communicable, maternal, neonatal, and nutritional (CMNN) causes accounted for 186% (17.9-19.6), and injuries 8.0% (7.7-8.2). Total numbers of deaths from NCD causes increased from 2007 to 2017 by 22.7% (21.5-23.9), representing an additional 7.61 million (7. 20-8.01) deaths estimated in 2017 versus 2007. The death rate from NCDs decreased globally by 7.9% (7.08.8). The number of deaths for CMNN causes decreased by 222% (20.0-24.0) and the death rate by 31.8% (30.1-33.3). Total deaths from injuries increased by 2.3% (0-5-4-0) between 2007 and 2017, and the death rate from injuries decreased by 13.7% (12.2-15.1) to 57.9 deaths (55.9-59.2) per 100 000 in 2017. Deaths from substance use disorders also increased, rising from 284 000 deaths (268 000-289 000) globally in 2007 to 352 000 (334 000-363 000) in 2017. Between 2007 and 2017, total deaths from conflict and terrorism increased by 118.0% (88.8-148.6). A greater reduction in total deaths and death rates was observed for some CMNN causes among children younger than 5 years than for older adults, such as a 36.4% (32.2-40.6) reduction in deaths from lower respiratory infections for children younger than 5 years compared with a 33.6% (31.2-36.1) increase in adults older than 70 years. Globally, the number of deaths was greater for men than for women at most ages in 2017, except at ages older than 85 years. Trends in global YLLs reflect an epidemiological transition, with decreases in total YLLs from enteric infections, respirator}, infections and tuberculosis, and maternal and neonatal disorders between 1990 and 2017; these were generally greater in magnitude at the lowest levels of the Socio-demographic Index (SDI). At the same time, there were large increases in YLLs from neoplasms and cardiovascular diseases. YLL rates decreased across the five leading Level 2 causes in all SDI quintiles. The leading causes of YLLs in 1990 neonatal disorders, lower respiratory infections, and diarrhoeal diseases were ranked second, fourth, and fifth, in 2017. Meanwhile, estimated YLLs increased for ischaemic heart disease (ranked first in 2017) and stroke (ranked third), even though YLL rates decreased. Population growth contributed to increased total deaths across the 20 leading Level 2 causes of mortality between 2007 and 2017. Decreases in the cause-specific mortality rate reduced the effect of population growth for all but three causes: substance use disorders, neurological disorders, and skin and subcutaneous diseases. Interpretation Improvements in global health have been unevenly distributed among populations. Deaths due to injuries, substance use disorders, armed conflict and terrorism, neoplasms, and cardiovascular disease are expanding threats to global health. For causes of death such as lower respiratory and enteric infections, more rapid progress occurred for children than for the oldest adults, and there is continuing disparity in mortality rates by sex across age groups. Reductions in the death rate of some common diseases are themselves slowing or have ceased, primarily for NCDs, and the death rate for selected causes has increased in the past decade. Copyright (C) 2018 The Author(s). Published by Elsevier Ltd.Peer reviewe