M.V. Gil

Thermal behaviour and kinetics of coal/biomass blends during co-combustion.

The thermal characteristics and kinetics of coal, biomass (pine sawdust) and their blends were evaluated under combustion conditions using a non-isothermal thermogravimetric method (TGA). Biomass was blended with coal in the range of 5-80 wt.% to evaluate their co-combustion behaviour. No significant interactions were detected between the coal and biomass, since no deviations from their expected behaviour were observed in these experiments. Biomass combustion takes place in two steps: between 200 and 360 degrees C the volatiles are released and burned, and at 360-490 degrees C char combustion takes place. In contrast, coal is characterized by only one combustion stage at 315-615 degrees C. The coal/biomass blends presented three combustion steps, corresponding to the sum of the biomass and coal individual stages. Several solid-state mechanisms were tested by the Coats-Redfern method in order to find out the mechanisms responsible for the oxidation of the samples. The kinetic parameters were determined assuming single separate reactions for each stage of thermal conversion. The combustion process of coal consists of one reaction, whereas, in the case of the biomass and coal/biomass blends, this process consists of two or three independent reactions, respectively. The results showed that the chemical first order reaction is the most effective mechanism for the first step of biomass oxidation and for coal combustion. However, diffusion mechanisms were found to be responsible for the second step of biomass combustion.

Mechanical durability and combustion characteristics of pellets from biomass blends.

Biofuel pellets were prepared from biomass (pine, chestnut and eucalyptus sawdust, cellulose residue, coffee husks and grape waste) and from blends of biomass with two coals (bituminous and semianthracite). Their mechanical properties and combustion behaviour were studied by means of an abrasion index and thermogravimetric analysis (TGA), respectively, in order to select the best raw materials available in the area of study for pellet production. Chestnut and pine sawdust pellets exhibited the highest durability, whereas grape waste and coffee husks pellets were the least durable. Blends of pine sawdust with 10-30% chestnut sawdust were the best for pellet production. Blends of cellulose residue and coals (<20%) with chestnut and pine sawdusts did not decrease pellet durability. The biomass/biomass blends presented combustion profiles similar to those of the individual raw materials. The addition of coal to the biomass in low amounts did not affect the thermal characteristics of the blends.

Co-gasification of different rank coals with biomass and petroleum coke in a high-pressure reactor for H2-rich gas production

Four coals of different rank were gasified, using a steam/oxygen mixture as gasifying agent, at atmospheric and elevated pressure in a fixed bed reactor fitted with a solids feeding system in continuous mode. Independently of coal rank, an increase in gasification pressure led to a decrease in H(2) + CO production and carbon conversion. Gasification of the different rank coals revealed that the higher the carbon content and reactivity, the greater the hydrogen production. Co-gasification experiments of binary (coal-biomass) and ternary blends (coal-petcoke-biomass) were conducted at high pressure to study possible synergetic effects. Interactions between the blend components were found to modify the gas production. An improvement in hydrogen production and cold gas efficiency was achieved when the coal was gasified with biomass.

Grindability and combustion behavior of coal and torrefied biomass blends.

Biomass samples (pine, black poplar and chestnut woodchips) were torrefied to improve their grindability before being combusted in blends with coal. Torrefaction temperatures between 240 and 300 °C and residence times between 11 and 43 min were studied. The grindability of the torrefied biomass, evaluated from the particle size distribution of the ground sample, significantly improved compared to raw biomass. Higher temperatures increased the proportion of smaller-sized particles after grinding. Torrefied chestnut woodchips (280 °C, 22 min) showed the best grinding properties. This sample was blended with coal (5-55 wt.% biomass). The addition of torrefied biomass to coal up to 15 wt.% did not significantly increase the proportion of large-sized particles after grinding. No relevant differences in the burnout value were detected between the coal and coal/torrefied biomass blends due to the high reactivity of the coal. NO and SO2 emissions decreased as the percentage of torrefied biomass in the blend with coal increased.

Production of adsorbents by pyrolysis of paper mill sludge and application on the removal of citalopram from water

This work describes the production of alternative adsorbents from industrial residues and their application for the removal of a highly consumed antidepressant (citalopram) from water. The adsorbents were produced by pyrolysis of both primary and biological paper mill sludge at different temperatures and residence times. The original sludge and the produced chars were fully characterized by elemental and proximate analyses, total organic carbon, specific surface area (BET), N₂ isotherms, FTIR, (13)C and (1)H solid state NMR and SEM. Batch kinetic and equilibrium experiments were carried out to describe the adsorption of citalopram onto the produced materials. The fastest kinetics and the highest adsorption capacity were obtained using primary sludge pyrolysed at 800 °C during 150 min. The use of pyrolysed paper mill sludge for the remediation of contaminated waters might constitute an interesting application for the valorization of those wastes.

A study of oxy-coal combustion with steam addition and biomass blending by thermogravimetric analysis

The thermal characteristics of pulverized coal have been studied under oxy-fuel combustion conditions using non-isothermal thermogravimetric analysis (TG). The atmospheres used were 21%O2/79%N2, 21%O2/79%CO2, 30%O2/70%O2, and 35%O2/65%CO2. Coal blends of coal with 10 and 20% of biomass were also studied under these atmospheres. The addition of 10 and 20% of steam was evaluated for the oxy-fuel combustion atmospheres with 21 and 30% of O2 in order to study the effect of the wet recirculation of flue gas. The results obtained were similar for all the different rank coals and indicated that replacing N2 by CO2 in the combustion atmosphere with 21% of O2 caused a slight decrease in the rate of mass loss and delayed the burning process of the coal, biomass and coal/biomass blend samples. When the O2 concentration was increased to 30 and 35% in the oxy-fuel combustion atmosphere, the rate of mass loss increased, the burning process occurred at lower temperatures and it was shorter in duration. An increase in the rate of mass loss and a reduction in burning time and temperature were observed after the addition of steam to the oxy-fuel combustion atmosphere. No relevant differences between the 10 and 20% steam concentrations were observed.

Multifunctional Pd/Ni–Co Catalyst for Hydrogen Production by Chemical Looping Coupled With Steam Reforming of Acetic Acid

High yield of high-purity H2 from acetic acid, a model compound of bio-oil obtained from the fast pyrolysis of biomass, was produced by sorption-enhanced steam reforming (SESR). An oxygen carrier was introduced into a chemical loop (CL) coupled to the cyclical SESR process to supply heat in situ for the endothermic sorbent regeneration to increase the energy efficiency of the process. A new multifunctional 1 %Pd/20 %Ni-20 %Co catalyst was developed for use both as oxygen carrier in the CL and as reforming catalyst in the SESR whereas a CaO-based material was used as CO2 sorbent. In the sorbent-air regeneration step, the Ni-Co atoms in the catalyst undergo strong exothermic oxidation reactions that provide heat for the CaO decarbonation. The addition of Pd to the Ni-Co catalyst makes the catalyst active throughout the whole SESR-CL cycle. Pd significantly promotes the reduction of Ni-Co oxides to metallic Ni-Co during the reforming stage, which avoids the need for a reduction step after regeneration. H2 yield above 90 % and H2 purity above 99.2 vol % were obtained.

Removal of fluoxetine from water by adsorbent materials produced from paper mill sludge

In this work, three adsorbents were produced by using as precursor primary paper mill sludge and applying KOH, NaOH or ZnCl2 as chemical activating agents (PS800-10KOH, PS800-10NaOH and PS800-10ZnCl2) and subjected to pyrolysis. The produced materials were tested for removal of fluoxetine from water, reported as one of the most persistent pharmaceuticals in the aquatic environment. Also, primary sludge pyrolysed under the same conditions but without activation (PS800-10) and a commercial activated carbon (PBFG4) were studied for comparison. Physical and chemical properties of the materials were determined and adsorption kinetic and equilibrium studies were performed in batch experiments. Equilibrium studies allowed testing the capacity of the produced materials for adsorb fluoxetine-HCl, showing no apparent correlation between the S(BET) areas and the adsorption capacities of the materials. The maximum adsorption capacity (mg g(-1)) was of 191.6±4.8 for PS800-10KOH; 136.6±9.6 for PS800-10NaOH; 28.4±0.3 for PS800-10ZnCl2; 120.4±2.5 for PS800-10 and 96.2±1.0 for PBFG4. It was demonstrated that many factors influence the removal of fluoxetine from solution and that the surface area is not the main factor in the process. Also the activation process did not enhance the properties of the produced materials.

Uso prudente de antibióticos y propuestas de mejora desde la medicina hospitalaria

The largest consumption of antimicrobials is concentrated in hospitals and within them, the intensive care units. The quality of antimicrobial use is not optimal, with up to 50% of prescriptions being unnecessary or inappropriate. Inappropriate antibiotic use leads to severe consequences, such as increased patient mortality and morbidity and bacterial resistance. The primary reason for inappropriate use is the insufficient knowledge of the increasingly vast and complex information about the diagnosis and treatment of infectious diseases. There is general agreement on the need to improve the use of antimicrobials in hospitals but not on how to improve it. University Hospital Virgen del Rocío (Seville) has launched the Institutional Programme for the Optimisation of Antimicrobial Treatment (PRIOAM), inspired by the recommendations of the Infectious Diseases Society of America and adapted to the structural, functional and cultural characteristics of the hospital. PRIOAM is coordinated by a multidisciplinary team chosen by the Committee on Infections and Antimicrobials and has three basic characteristics: it is an institutional programme that has incentives linked to achieving goals; it is an educational programme in which training and knowledge are the basis for the proper use of antimicrobials; and it is a programme subject to results, in which the main objectives are clinical, not economic, to reduce mortality and morbidity in patients with infections and to delay the development of resistance.The largest consumption of antimicrobials is concentrated in hospitals and within them, the intensive care units. The quality of antimicrobial use is not optimal, with up to 50% of prescriptions being unnecessary or inappropriate. Inappropiate antibiotic use leads to severe consequences, such as increased patient mortality and morbidity and bacterial resistance. The primary reason for inappropriate use is the insufficient knowledge of the increasingly vast and complex information about the diagnosis and treatment of infectious diseases. There is general agreement on the need to improve the use of antimicrobials in hospitals but not on how to improve it. University Hospital Virgen del Rocio (Seville) has launched the Institutional Programme for the Optimisation of Antimicrobial Treatment (PRIOAM), inspired by the recommendations of the Infectious Diseases Society of America and adapted to the structural, functional and cultural characteristics of the hospital. PRIOAM is coordinated by a multidisciplinary team chosen by the Committee on Infections and Antimicrobials and has three basic characteristics: it is an institutional programme that has incentives linked to achieving goals; it is an educational programme in which training and knowledge are the basis for the proper use of antimicrobials; and it is a programme subject to results, in which the main objectives are clinical, not economic, to reduce mortality and morbidity in patients with infections and to delay the development of resistance.

Lesión cutánea foruncular en un viajero procedente de un país sudamericano

La miasis es la infestacion de los tejidos y organos de mamiferos por larvas de distintas especies de dipteros que en ocasiones puede afectar al hombre1. D. hominis, conocida tambien como mosca zumbadora tropical, de la familia Cuterebridae es una mosca con una amplia distribucion en America tropical y subtropical, mientras que en Espana no existen casos autoctonos1-4. La hembra de D. hominis utiliza insectos hematofagos en los que realiza una ovoposicion sobre su abdomen para transportar sus huevos hacia el huesped. Cuando alguno de los portadores se alimenta de un mamifero se produce la eclosion de las larvas, posiblemente favorecida por el Caso clinico