¿Cómo tomarse una cerveza fría en el desierto?

Duración (en horas): De 31 a 40 horas Nivel educativo:GradoEl problema ABP propuesto pretende impulsar la capacidad del alumno a la hora de plantear y resolver adecuadamente balances de energía entálpicos en sistemas de intercambio de calor. El problema se centra en el diseño de un dispositivo de enfriamiento instantáneo comercializado bajo el nombre de “bolsa de frío”. Este problema permite que el alumno se pregunte cómo es posible enfriar una sustancia sin necesidad de un aparato eléctrico. La resolución del problema implica que los alumnos identifiquen, en primer lugar, la información necesaria; conceptos tales como calor específico, calor de reacción y, posteriormente, resuelvan el balance de energía para el conjunto bolsa de frío y producto enfriado; cerveza en este caso

Ikatz aktiboaren prestaketa, karakterizazioa eta erabilpena uren arazketan

Artikulu honetan ikatz aktiboa zer den azaltzeaz gain, bere prestaketa, karakterizazioa eta ezaugarri kimiko eta fisikoei buruzko xehetasunak emango dira. Azken atalean, ikatzaren hautakortasunak duen garrantzia ulertzeko, bi solutu organikorekin egindako saiakuntza batzuk aurkeztuko dira

Desinfekzioaren azpiproduktuak edateko uretan

Gauza guztiek behar omen dute bere neurria, baita gure mesederako erabiltzen direnek ere. Kloroa dugu horren adibide garbietako bat. Edateko ura desinfektatzeko erabiltzen da, baina bere erabilera zorrotz neurtu/arautu behar da kaltegarriak diren zenbait sustantzia ere sortzen baititu. Hauek desinfekzioaren azpiproduktuak izenaz ezagutzen dira eta kloroaren eta uretan dagoen materia organikoaren arteko erreakziotik sortzen dira

¿Cómo tomarse una cerveza fría en el desierto?

Duración (en horas): De 31 a 40 horas Nivel educativo:GradoEl problema ABP propuesto pretende impulsar la capacidad del alumno a la hora de plantear y resolver adecuadamente balances de energía entálpicos en sistemas de intercambio de calor. El problema se centra en el diseño de un dispositivo de enfriamiento instantáneo comercializado bajo el nombre de “bolsa de frío”. Este problema permite que el alumno se pregunte cómo es posible enfriar una sustancia sin necesidad de un aparato eléctrico. La resolución del problema implica que los alumnos identifiquen, en primer lugar, la información necesaria; conceptos tales como calor específico, calor de reacción y, posteriormente, resuelvan el balance de energía para el conjunto bolsa de frío y producto enfriado; cerveza en este caso

Effect of the synthesis method on the performance of Ni-CeO2-ZrO2 catalysts for the hydrogenolysis of glycerol with endogenous hydrogen

In this work, we investigated the influence of the synthesis method of Ni-based CeZr catalysts on their physicochemical and catalytic properties in the hydrogenolysis (HDO) of glycerol with H2 in-situ produced by the aqueous-phase reforming (APR). Conventional impregnation method involved surface nickel deposition (NiCeZr-IM). The one-pot methods, which involved nickel embedment into CeZr lattice, included sol-gel (NiCeZr-SC) and coprecipitation (NiCeZr-CA and ultrasound-assisted NiCeZR-CS) methods. Differences in textural, structural, morphological, redox, and surface properties, together with and catalytic performance in the glycerol APR-HDO, were investigated systematically. As well, spent catalysts were deeply characterized. There were notable differences among textural properties, which significantly affected their activity in glycerol conversion. The structural characterization confirmed the successful integration of Ni into the CeZr lattice, especially for the catalysts synthesized using one-pot methods. One-pot synthesized catalysts showed stronger Ni-CeZr interaction, which affect the reducibility. The catalysts prepared by coprecipitation contained the highest metal-to-acid ratio, making them very active for C-O bond hydrogenation. Post-reaction characterization discloses a leaching of the nickel, in greater amount for both coprecipitated catalysts. This study revealed the potential of Ni-based catalysts derived from subsurface insertion of nickel into the CeZr matrix for the hydrogenolysis of glycerol without external hydrogen.Ministerio de Ciencia e Innovación, PID2019-106692RB-I0

Nickel aluminate spinel-derived catalysts for the aqueous phase reforming of glycerol: Effect of reduction temperature

Bulk nickel aluminate (NiAl2O4) was synthesised by co-precipitation at a Ni/Al mole ratio of 1:2 (stoichiometric ratio). The prepared sample was reduced at different temperatures, in the 300 to 850 ºC range, and obtained assays were analysed by a wide range of analytical techniques (XFR, XRD, H2-chemisoprtion, H2-TPR, DRS UV-vis NIR, FTIR, 27Al MAS NMR, NH3-TPD, CO2-TPD, TPO) and tested for the APR of glycerol. The spinel precursor allowed the formation of small and stable Ni particles (< 14 nm) upon reduction with good performance in the APR of glycerol (NiAl-850 93% conversion, 57% conversion to gas, at 250 ºC/45 bar and WHSV 24.5 h-1). Hydrogen was the main gaseous product and the activation temperature did not substantially alter selectivity to gaseous products; however, selectivity to intermediate oxygenated liquid compounds was substantially modified. Overall, glycerol dehydrogenation route was dominant at high reduction temperature. The good stability of the spinel led to stable H2 yield in the long-term runs (50 hours) and proved potential to be used in the APR of glycerol.Ministerio de Economía y Competitividad, ENE2016-7450-

Olefina arinen ekoizpena: egungo egoera eta aurreikuspenak

Light olefins (especially, ethylene and propylene) are the key building blocks of the petrochemical industry and they are mainly used to produce polyolefins (polyethylene and polypropylene). Nowadays, light olefin demand is continuosly increasing, where ethylene demand shows an annual average rate of 3-5% and propylene of 5-7%. Ethylene demand is satisfied by ethane steam cracking (SC) process. However, in order to fulfill the propylene demand, the selectivity achieved by conventional technologies (SC and fluid catalytic cracking (FCC)) should be improved. Furthermore, these industrial technologies show a great dependence on fossil fuels and a high energy consumption.Thus, improving these conventional technologies, as well as developing alternative processes based on rewenable sources are the main challenges for the refineries and the petrochemical industries. In this work, the main applications of light olefins and their worldwide demand are firstly analyzed. Then, the conventional technologies (from fossil fuels) are described; and, finally, other sustainable techonologies are discussed, which are based on the valorization of biomass and wastes.; Olefina arinak (bereziki, etilenoa eta propilenoa) industria petrokimikoko oinarrizko lehengaiak dira eta poliolefinak (polietilenoa eta polipropilenoa) ekoizteko erabiltzen dira nagusiki. Gaur egun, olefinen eskaria handituz doa: etilenoaren eskariak urteko % 3-5eko igoera izan du, eta propilenoak, aldiz, % 5-7koa. Etilenoaren eskaria bermatuta dago etanoaren ur-lurrun bidezko cracking termiko (SC) prozesuaren bitartez, baina propilenoaren eskaria betetzeko, ohiko prozesuek (SC eta cracking katalitikoa ohantze fluidizatuan (FCC)) eskaintzen duten hautakortasuna hobetu beharra dago. Gainera, industria-mailan ezarritako teknologiek erregai fosilen mendekotasun eta energia-kontsumo handia dute. Beraz, ohiko teknologiak hobetzea eta iturri berriztagarriak erabiltzen dituzten prozesuak garatzea dira gaur egungo findegiaren eta industria petrokimikoaren erronka nagusiak. Artikulu honetan, lehendabizi, olefina arinen erabilerak eta haien eskaria mundu-mailan aztertuko dira. Jarraian, ohiko teknologiak deskribatuko dira (iturri fosiletik abiatuz) eta, azkenik, bestelako teknologia berriztagarriak aurkeztuko dira, biomasaren eta hondakinen balorizazioan oinarritzen direnak

Aqueous-Phase Glycerol Conversion over Ni-Based Catalysts Synthesized by Nanocasting

[EN] A morphological strategy consisting of nanocasting synthesis of nickel aluminate spinel precursor was addressed. Two nanocasted catalysts were synthesized involving different template-removal procedures (i.e., Teflon-assisted calcination vs. NaOH washing) for spinel recovery. As a reference, spinel NiAl2O4 supported by SBA-15 and bare nickel aluminate spinel were selected. The obtained solids were characterized in detail, examining their textural, acid–base, structural and compositional characteristics, either in the calcined or reduced forms. The as-obtained catalysts’ performance was evaluated in the aqueous-phase reforming of glycerol at 235 °C and 35 bar. Exhausted samples were also characterized to enlighten changes in catalyst properties during the aqueous-phase reaction. NiAl/SBA-15 and NiAl-NCF catalyst showed very poor catalytic performance for the glycerol transformation. NiAl-NCN catalyst presented improved activity with respect to NiAl, with a 20% higher hydrogen production rate but, as a drawback, higher methane formation for a whole range of glycerol conversions. Exhausted catalyst indicated nickel oxidized in liquid phase reaction.This research was supported by grant PID2019-106692EB-I00 funded by MCIN/AEI/ 10.13039/501100011033

Bimetallic Pt-Co Catalysts for the Liquid-Phase WGS

[EN] Bimetallic Pt-Co catalysts derived from cobalt aluminate spinel were investigated in the liquid-phase water–gas shift (WGS) reaction and CO hydrogenation. Liquid-phase WGS is a key reaction in the aqueous-phase reforming (APR) of polyols; thus, WGS activity is essential to formulate good APR catalysts. In this work, catalysts with different Pt/Co molar ratios were synthesized together with a reference Pt/alumina. All the synthesized catalysts were characterized by various techniques in order to gain knowledge on their structural and surface characteristics. WGS activity was tested with a feedstream of CO/H2O = 1/15 (space-time of 76.8 kg·s/molCO), isothermal operation at 260 ºC and 50 bar, for 10 TOS. Bimetallic Pt-Co catalysts showed improved activity in liquid-phase WGS in comparison to bare Co or Pt catalysts, which was ascribed to the synergistic effect. Despite being subjected to an increased hydrogen concentration in the feedstream (H2/CO between 0 and 12/3), these catalysts maintained a preferential selectivity towards WGS activity. In addition, the effect of temperature (220–260 ºC) and pressure (25–50 bar) was investigated over a catalyst with 0.3Pt/CoAl. CO conversion and CO2 yield were more sensitive to temperature, while a higher pressure favored methane production. The measured activation energy in the 220–260 ºC temperature range was 51.5 kJ/mol.This research was funded by Mineco (ENE2016-74850-R and PID2019-106692EB-I00) and FEDER. The APC was funded by ENE2016-74850-R. A.J.R. was supported by a PhD research fellowship provided by the University of the Basque Country UPV/EHU (PIF-17/319)