Análisis técnico-económico para la producción de alquilbenceno lineal

El presente trabajo muestra un análisis técnico-económico de una planta de producción de alquilbenceno lineal, basándose en la alquilación del queroseno con benceno y ácido fluorhídrico, método más usado comercialmente. El objetivo del proyecto es exponer los diferentes equipos que componen una unidad de alquilación para la producción de 260.000 t/año de alquilbenceno lineal, LAB, y hacer una estimación de los costes de inversión. La Unidad de Alquilación está formada por la unidad Unifining, encargada de eliminar los compuestos nocivos del queroseno; la unidad Molex, encargada de separar las parafinas lineales de las ramificadas mediante un tamiz de zeolita 5A; la unidad Pacol, con el objetivo de convertir las parafinas lineales en olefinas lineales; la unidad Define, que consiste en la transformación de las diolefinas formadas en la unidad Pacol en olefinas lineales y por último, la etapa de alquilación donde las olefinas lineales se transforman en LAB con benceno usando como catalizador ácido fluorhídrico.The present study shows a technical-economical analysis of a lineal alkylbenzene production plant, basing it on alkylation of kerosene with benzene and hydrofluoric acid, being the most commercially used method. The purpose of this project is to expose the different equipment used in the composition of a 260.000 t/year production of lineal alkylbenzene in an alkylation unit and to do an estimation of inversion costs. The alkylation Unit is formed by the Unifining unit, in charge to eliminate the harmful compounds of the kerosene; the Molex unit, responsible of separating linear paraffins from the branched ones using a zeolite 5A sieve; the Pacol unit, with the aim of converting linear paraffins into linear olefins; the Define unit, which consists on the transformation of the diolefins formed in the Pacol unit into linear olefins and, finally, the alkylation stage where the linear olefins are transformed into LAB with benzene using hydrofluoric acid as a catalyst.Universidad de Sevilla. Grado en Ingeniería de Tecnologías industriale

Potential for water and metal recovery from acid mine drainage by combining hybrid membrane processes with selective metal precipitation

Acid mining drainage has a serious impact on the environment. Forward osmosis allows the concentration of acid mine waters to favor the formation of enrichment sludges and subsequent selective metal precipitation. In this work, a methodology was proposed to treat mining effluents from the Iberian Pyrite Belt. Forward osmosis experiments were performed using different osmotic pressures from 0.5M to 2.5M NaCl to evaluate water fluxes and recovery. The water recovery obtained was in the range of 50-80%, and the flux remained above 5 (L•m−2•h−1). Four combined processes were modelled to determine the feasibility of eliminating water and precipitating metals. Furthermore, a new hybrid membrane process was proposed to recover at least 75% of water with recovery yields of Al, Fe, Cu, Zn and Mn of greater than 70%. A water production cost of 2.01 $/m3 and a specific energy consumption of 8.03 kWhe/m3 were estimated for the hybrid process

Evidence of Cognitive and Neurophysiological Impairment in Patients with Untreated Naive Acromegaly

Context: Recent studies have suggested that long-term exposure to high levels of GH and IGF-I affect brain and cognitive functions. However, very few human studies have challenged this hypothesis. Objective: The aim of this study is to explore whether GH/IGF-I excess in naive patients with acromegaly alters cognitive functions, particularly memory, and whether these alterations are accompanied by neurophysiological correlates. Design: We conducted a comprehensive neuropsychological and neurophysiological exam on 16 naive acromegaly patients and 16 strictly matched healthy controls. Comparative analyses were carried out on major neurocognitive domains (executive functions, visual/verbal memory, attention, visuoconstructive abilities, and verbal fluency) and on quantitative electroencephalogram and low-resolution brain electromagnetic tomography sources. Results were correlated with GH and IGF-I hormone concentrations. Results: Short- and long-term memory were the most severely impaired cognitive functions. Moreover, memory performance correlated negatively with GH and IGF-I concentrations. No association was detected between depression and memory impairment, and only a marginal association was found with quality of life. Finally, acromegaly patients showed power attenuation in fast frequency electroencephalogram bands, as well as decreased activity in prefrontal and middle temporal cortices, that was associated to cognitive performance. Conclusions: Results provide evidence of cognitive and neurophysiological impairment, characterized by moderate-to-severe memory impairment and decreased neural activity in specific brain areas. High levels of GH and IGF-I in acromegaly patients could be the basis for these findings

Microorganisms isolated from blood cultures in children with cancer and high-risk febrile neutropenia from five hospitals in Santiago, Chile, 2012-2015 Microorganismos aislados de hemocultivos en niños con cáncer y neutropenia febril de alto riesgo en cin

© 2018, Sociedad Chilena de Infectologia. All rights reserved. Background: Microorganisms isolated from blood cultures (BC) in patients with febrile neutropenia (NF) vary over time, requiring systematic monitoring to guide appropriate empirical therapy. Aim: To identify microorganisms isolated from BC and their antimicrobial resistance profile in children with cancer and high risk NF. Method: Prospective, multicenter study. The analysis included episodes of high-risk FN with positive BC in children under 18 years of age treated in five hospitals in Santiago, Chile, 2012-2015. Results: A total of 206 microorganisms were analyzed in 185 episodes of high-risk FN. The main isolates were Gram negative bacilli (46.6%) and Gram positive cocci (45.1%) and the most frequent microorganisms were Escherichia coli (22.8%), coagulase negative Staphylococcus (18.0%) and Klebsiella spp. (16.5%). Escherichia coli and Klebsiella spp showed 4.2% and 67.6% resistance to third generation cephalosporins (c