Infrared sensor-based temperature control for domestic induction cooktops

In this paper, a precise real-time temperature control system based on infrared (IR) thermometry for domestic induction cooking is presented. The temperature in the vessel constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooker. A proportional-integral controller is applied to establish the output power level in order to reach the target temperature. An optical system and a signal conditioning circuit have been implemented. For the signal processing a microprocessor with 12-bit ADC and a sampling rate of 1 Ksps has been used. The analysis of the contributions to the infrared radiation permits the definition of a procedure to estimate the temperature of the vessel with a maximum temperature error of 5 °C in the range between 60 and 250 °C for a known cookware emissivity. A simple and necessary calibration procedure with a black-body sample is presented

ANÁLISIS DE LA POBREZA Y EXCLUSIÓN SOCIAL EN ESPAÑA

La pobreza y la exclusión social son dos problemas interrelacionados cuyas consecuencias afectan a millones de personas en el mundo. Las causas de la pobreza y exclusión social no sólo están relacionadas con el ámbito económico, sino que existen diversos factores que las provocan, el acceso a los recursos o el territorio al que pertenezcas, entre otros. Actualmente, es un tema de relevante importancia debido al gran crecimiento que ha obtenido tras la crisis económica y financiera iniciada en 2008, afectando a un gran número de hogares en España. Según los datos obtenidos de la revisión de diferentes fuentes bibliográficas oficiales, se observa que los colectivos más más vulnerables a esta situación de pobreza y exclusión social son especialmente las mujeres, los jóvenes entre 16 y 29 años, las familias monoparentales y los hogares con menores. Estos efectos se pretenden reducir mediante políticas como la estrategia Europa 2020 impulsada por la Unión Europea o a través de la Agenda 2030 sobre los Objetivos de Desarrollo Sostenible (ODS) de las Naciones Unidas.<br /

Polymer–ceramic composite membranes for water removal in membrane reactors

Methanol can be obtained through CO2 hydrogenation in a membrane reactor with higher yield or lower pressure than in a conventional packed bed reactor. In this study, we explore a new kind of membrane with the potential suitability for such membrane reactors. Silicone–ceramic composite membranes are synthetized and characterized for their capability to selectively remove water from a mixture containing hydrogen, CO2, and water at temperatures typical for methanol synthesis. We show that this membrane can achieve selective permeation of water under such harsh conditions, and thus is an alternative candidate for use in membrane reactors for processes where water is one of the products and the yield is limited by thermodynamic equilibrium

Modifications in the composition of cuo/zno/al2o3 catalyst for the synthesis of methanol by co2 hydrogenation

Renewable methanol, obtained from CO2 and hydrogen provided from renewable energy, was proposed to close the CO2 loop. In industry, methanol synthesis using the catalyst CuO/ZnO/Al2O3 occurs at a high pressure. We intend to make certain modification on the traditional catalyst to work at lower pressure, maintaining high selectivity. Therefore, three heterogeneous catalysts were synthesized by coprecipitation to improve the activity and the selectivity to methanol under mild conditions of temperature and pressure. Certain modifications on the traditional catalyst Cu/Zn/Al2O3 were employed such as the modification of the synthesis time and the addition of Pd as a dopant agent. The most efficient catalyst among those tested was a palladium-doped catalyst, 5% Pd/Cu/Zn/Al2O3. This had a selectivity of 64% at 210 °C and 5 bar

Methanol to Gasoline (MTG): preparation, characterization and testing of HZSM-5 zeolite-based catalysts to be used in a fluidized bed reactor

The preparation of catalysts suitable for MTG processes in a fluidized bed reactor has been studied with emphasis on improving the textural, physico-chemical, morphological, structural and mechanical properties. A mixture of HZSM-5 zeolite (active material), boehmite or bentonite (binder) and alumina (inert filler) was used to prepare different catalysts. After preparation, characterization by physical adsorption of N2, XRF, XRD and SEM-EDX techniques was carried out. The screening of catalysts was performed in a fluidized bed reactor. The distribution of products was very similar in all cases, with the yield of light hydrocarbons always being higher than that of gasoline. Among the catalysts tested, the one containing boehmite as a binder (HZ_Boeh) was found as the most appropriate due to its high mechanical strength, high yield to aromatics and lower yield to durene

Methanol to gasoline (MTG): Parametric study and validation of the process in a two-zone fluidized bed reactor (TZFBR)

Methanol to Gasoline (MTG) process transforms methanol to hydrocarbons within the boiling point range of gasoline. The result is a wide spectrum of products (olefins, paraffins, aromatics and naphthenics, among others), with the total conversion of methanol to hydrocarbons and water. Catalyst deactivation by coke is a main problem in this process. This work aims to determine the feasibility of carrying out the production of gasoline from methanol in a two-zone fluidized bed reactor (TZFBR). The hypothesis is that the formation of carbonaceous deposits (coke) on the catalyst particles can be counteracted by its combustion in the regeneration zone that this novel reactor presents, thus achieving stable and continuous operation. In this way, both processes (reaction and regeneration) would be being carried out simultaneously in the same reactor (process intensification). The comparison of results between a conventional fluidized bed reactor and a TZFBR shows that the second one actually provides a better stability over time

MTO with SAPO-34 in a Fixed-Bed reactor: deactivation profiles

Methanol-to-olefins is a promising process that has attracted the attention of many research groups in the last years. Zeolites are the primary catalyst for this process, and SAPO-34 is one of the most used because of its high selectivity toward C2-C4 olefins. As a drawback, it deactivates quickly and forces the process to work alternately using reaction and regeneration cycles. The mechanism by which SAPO-34 deactivates is still on debate, and further research needs to be done. In this study, the evolution of the deactivation profile for an SAPO-34-based catalyst was studied in a fixed-bed reactor. To achieve that, the catalyst bed was extracted after each experiment and divided in sections of 2 cm. For each section, CO2 adsorption, thermogravimetric analysis, and ammonia temperature-programmed desorption were performed

La naissance d´un nouveau groupe social dans la France des années soixante : les jeunes.

Pendant les années soixante du vingtième siècle s´est produite une étonnante transformation sociale, aussi bien en France que dans différents pays européens. Après la destruction à tous les niveaux entraînée par la deuxième guerre mondiale, une nouvelle vague de naissances s´est produite pendant les quinze années ultérieures à la fin du conflit armé. Ce phénomène se traduit par un impact démographique éblouissant dans les années soixante, décennie où tous ces babyboomers sont en différentes âges de jeunesse. Cette mémoire de fin de licence porte sur cette nouvelle génération française et son influence. Après une contextualisation historique, économique, politique et sociale, on se plonge sur les différents traits distinctifs ainsi que culturels de ce nouveau groupe social tels que la musique, la mode vestimentaire ou les médias. Enfin, une approche du poids des jeunes dans les champs de la politique et l´éducation est menée à terme, d´autant que son arrivée choqua le système éducatif et ébranla les institutions, gouvernants et mœurs dites traditionnels. <br /

Lindane removal by membrane nanofiltration

Lindane is the γ-isomer of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and it has been widely used in the pesticide industry due to its insecticide properties. In the production of lindane, significant quantities of other HCH isomers are generated as byproducts. All these compounds are typically stored in landfills, often with poor management practices. Polyamide membranes, two commercial membranes from Alfa Laval (NF99HF and NF99) and homemade thin film composite membranes prepared by interfacial polymerization on a porous polyimide support, were evaluated for water nanofiltration (NF) of HCH isomers, including lindane. Homemade membranes, with a lindane rejection of 91.3 % and a permeance of 2.7 L·m−2·h−1·bar−1, offered the highest performance in terms of both permeance and rejection. NF99 and homemade membranes were proven to be equally effective in removing α-HCH and β-HCH, showing similar results. Homemade membranes achieved 99.5 and 99.8 % rejections for α-HCH and β-HCH, respectively. Long-term experiments were carried out with NF99 and homemade membranes to assess their stability during filtrations with lindane solutions for up to 214 h. Homemade TFC membrane maintained its initial rejection (ca. 93.5 %) after 214 h, although its permeance decreased over time, ending in 2.5 L·m−2·h−1·bar−1

Dry reforming of biogas in fluidized bed: Process intensification

Biogas is a renewable resource obtained mainly from the anaerobic fermentation of agro-industrial and anthropogenic residues. The production of hydrogen by dry reforming of methane represents a potential application for this renewable energy carrier. This could play a positive contribution towards meeting the challenge of providing a global supply of energetically sustainable and environmentally friendly energy. This work combines a catalytic reaction, a separation and the catalyst regeneration in a single reactor. To this end, a two zone fluidized bed reactor (TZFBR) with hydrogen selective membranes has been employed (TZFBR + MB). The operating conditions for the process of dry reforming of biogas have been optimized experimentally, both in TZFBR and TZFBR + MB. Several catalysts were prepared (Ni/Al2O3, Ni–Ce/Al2O3, Ni–Co/Al2O3), characterized and tested in reactions in both TZFBR and in TZFBR + MB. Finally, the influence of using oxygen or carbon dioxide as regenerating gases in the process has been studied. Experimental results show the feasibility of using CO2 for in situ catalyst regeneration, avoiding the potential problems associated with the use of O2