Sistema de protección contra incendios de un parque de almacenamiento de líquidos petrolíferos

Los procesos relacionados con el almacenamiento y manipulación de productos petrolíferos, conllevan siempre determinados riesgos de incendio que dependen básicamente de las propiedades físicas y químicas de los productos, y hacen indispensable la adopción de importantes medidas de seguridad contra incendios. Esto es debido a que las consecuencias previsibles en caso de la producción y expansión del incendio son tan graves que aconsejan la instalación de medios más potentes de lucha contra incendios, que los simples extintores manuales. En base a ello, el presente proyecto pretende definir y desarrollar una propuesta de diseño del sistema de protección contra incendios en la zona de almacenamiento de una planta de almacenamiento de líquidos petrolíferos. La planta almacena Gasóleo, Gasolina y Queroseno de Aviación en ocho tanques atmosféricos de techo fijo situados en un único cubeto de retención. Se desarrolla un extenso estudio de los requisitos normativos para este tipo de casos, y en consecuencia, se calcula y clasifica el nivel de riesgo intrínseco de incendio en la zona estudiada, a partir de su carga de fuego ponderada y corregida. Además, se muestra la distribución de los tanques en el cubeto, basada en el cálculo de las distancias de seguridad entre cada uno de ellos y con el exterior. A partir de ello, el proyecto se centra en el cálculo de los valores de descarga de agua de refrigeración, requeridos en las boquillas de agua pulverizada e hidrantes exteriores de alrededor de la zona de riesgo; de espuma física para hidrocarburos, en las cámaras de espuma de la parte superior de la envolvente de los tanques, y en los monitores auxiliares de descarga de espuma, de la zona del cubeto de retención. Los objetivos, métodos y bases de cálculo se recogen en la memoria del proyecto. Además se incluye, la planificación temporal con MS Project, de la implementación del proyecto; la elección de los equipos que componen los sistemas, el presupuesto asociado y los planos de distribución de la planta y del flujo de tuberías propuesto. ABSTRACT Fire protection units and equipment are necessary on processes and operations related to storage and handling of petroleum products, because of their flammable and combustible properties. In case a hazard of fire from petroleum products is materialized, huge consequences are to be expected. To reduce losses, facilities should be equipped with appropriate protection. Based on that, this project seeks to define and develop the fire protection system design for a petroleum liquids storage installation. The plant stores Gasoil, Gasoline, and aviation Kerosene in eight fixed roof atmospheric tanks. A complete study of the fire protection regulations is carried out and, as a result, the studied area’s risk level is determined from its fire load density. The calculation of the minimum shell-to-shell spacing of adjacent aboveground storage tanks and external equipment, is also determined for a correct distribution of tanks in the bunded area. Assuming that, the design includes calculations of required discharge of water for spray nozzles and hydrants, and required discharge of foam from foam chambers and foam monitors. Objectives, methodology and calculation basis are presented on the project technical report; which also includes project scheduling with MS. Project software, the selection of system components and equipment, related budget and lay out of installation and piping.

Simulación del Tren de Licuación del Proyecto Gorgon LNG

El proyecto abarca el estudio, análisis y dimensionamiento del tren de Licuación Gas Natural del proyecto Gorgon LNG basado en la tecnología AP/C3MR de Air Products. Este estudio cubre toda la evolución del gas natural dentro del tren de licuación, antes de ser enviado a los tanques de almacenamiento, apoyándose en procesos de simulación informática. Como parte de este proyecto, se realiza una propuesta de todos los equipos (intercambiadores de calor, turbinas de gas, compresores, etc.) necesarios para la consecución del proceso teniendo como base los datos resultantes del proceso de simulación llevado a cabo. Una vez realizada tanto la simulación del proceso como la propuesta de equipos, se hace una valoración económica del proyecto que confirme la viabilidad de este tipo de tecnología, enmarcándola en el mercado de combustibles actual.

Desarrollo de un sistema de almacenamiento térmico para la central termosolar Astexol 2

En este proyecto se elabora la ingeniería básica de un sistema de almacenamiento térmico para la central termosolar Astexol 2 (Badajoz, España). Para ello, primeramente se decidió que el sistema térmico de almacenamiento a diseñar fuera indirecto de dos tanques con sales fundidas. Una vez seleccionado el tipo de almacenamiento adecuado, se seleccionó la capacidad de almacenamiento óptima, en base a unos objetivos establecidos para la instalación del TES en Astexol 2. Finalmente, se procedió con el diseño de los equipos principales y con la realización de los planos de implantación y de los PFD’s (diagramas de flujo) y P&ID’s (diagramas de instrumentación y control) del sistema de almacenamiento. ABSTRACT This project includes the basic engineering of a thermal storage system for the concentrating solar power plant Astexol 2 (Badajoz, Spain). First of all, it was decided that the type of thermal storage system to design had to be an indirect two-tank molten salt thermal storage system. Once the proper type of storage system was chosen, the optimum storage capacity was selected, according to the main aims designated for the thermal storage system installation in Astexol 2.Finally, the design of the main equipment of the thermal storage system was done, together with the elaboration of the associated plot plans, PFD’s (Process Flow Diagrams) and P&ID’s (Process and Instrumentation Diagrams).

Experimental and statistical investigation of canonical problems in sloshing

En hidrodinámica, el fenómeno de Sloshing se puede definir como el movimiento de la superficie libre de un fluido dentro de un contenedor sometido a fuerzas y perturbaciones externas. El fluido en cuestión experimenta violentos movimientos con importantes deformaciones de su superficie libre. La dinámica del fluido puede llegar a generar cargas hidrodinámicas considerables las cuales pueden afectar la integridad estructural y/o comprometer la estabilidad del vehículo que transporta dicho contenedor. El fenómeno de Sloshing ha sido extensivamente investigado matemática, numérica y experimentalmente, siendo el enfoque experimental el más usado debido a la complejidad del problema, para el cual los modelos matemáticos y de simulación son aun incapaces de predecir con suficiente rapidez y precisión las cargas debidas a dicho fenómeno. El flujo generado por el Sloshing usualmente se caracteriza por la presencia de un fluido multifase (gas-liquido) y turbulencia. Reducir al máximo posible la complejidad del fenómeno de Sloshing sin perder la esencia del problema es el principal reto de esta tesis doctoral, donde un trabajo experimental enfocado en casos canónicos de Sloshing es presentado y documentado con el objetivo de aumentar la comprensión de dicho fenómeno y por tanto intentar proveer información valiosa para validaciones de códigos numéricos. El fenómeno de Sloshing juega un papel importante en la industria del transporte marítimo de gas licuado (LNG). El mercado de LNG en los últimos años ha reportado un crecimiento hasta tres veces mayor al de los mercados de petróleo y gas convencionales. Ingenieros en laboratorios de investigación e ingenieros adscritos a la industria del LNG trabajan continuamente buscando soluciones económicas y seguras para contener, transferir y transportar grandes volúmenes de LNG. Los buques transportadores de LNG (LNGC) han pasado de ser unos pocos buques con capacidad de 75000 m3 hace unos treinta años, a una amplia flota con una capacidad de 140000 m3 actualmente. En creciente número, hoy día se construyen buques con capacidades que oscilan entre 175000 m3 y 250000 m3. Recientemente un nuevo concepto de buque LNG ha salido al mercado y se le conoce como FLNG. Un FLNG es un buque de gran valor añadido que solventa los problemas de extracción, licuefacción y almacenamiento del LNG, ya que cuenta con equipos de extracción y licuefacción a bordo, eliminando por tanto las tareas de transvase de las estaciones de licuefacción en tierra hacia los buques LNGC. EL LNG por tanto puede ser transferido directamente desde el FLNG hacia los buques LNGC en mar abierto. Niveles de llenado intermedios en combinación con oleaje durante las operaciones de trasvase inducen movimientos en los buques que generan por tanto el fenómeno de Sloshing dentro de los tanques de los FLNG y los LNGC. El trabajo de esta tesis doctoral lidia con algunos de los problemas del Sloshing desde un punto de vista experimental y estadístico, para ello una serie de tareas, descritas a continuación, se han llevado a cabo : 1. Un dispositivo experimental de Sloshing ha sido configurado. Dicho dispositivo ha permitido ensayar secciones rectangulares de tanques LNGC a escala con movimientos angulares de un grado de libertad. El dispositivo experimental ha sido instrumentado para realizar mediciones de movimiento, presiones, vibraciones y temperatura, así como la grabación de imágenes y videos. 2. Los impactos de olas generadas dentro de una sección rectangular de un LNGC sujeto a movimientos regulares forzados han sido estudiados mediante la caracterización del fenómeno desde un punto de vista estadístico enfocado en la repetitividad y la ergodicidad del problema. 3. El estudio de los impactos provocados por movimientos regulares ha sido extendido a un escenario más realístico mediante el uso de movimientos irregulares forzados. 4. El acoplamiento del Sloshing generado por el fluido en movimiento dentro del tanque LNGC y la disipación de la energía mecánica de un sistema no forzado de un grado de libertad (movimiento angular) sujeto a una excitación externa ha sido investigado. 5. En la última sección de esta tesis doctoral, la interacción entre el Sloshing generado dentro en una sección rectangular de un tanque LNGC sujeto a una excitación regular y un cuerpo elástico solidario al tanque ha sido estudiado. Dicho estudio corresponde a un problema de interacción fluido-estructura. Abstract In hydrodynamics, we refer to sloshing as the motion of liquids in containers subjected to external forces with large free-surface deformations. The liquid motion dynamics can generate loads which may affect the structural integrity of the container and the stability of the vehicle that carries such container. The prediction of these dynamic loads is a major challenge for engineers around the world working on the design of both the container and the vehicle. The sloshing phenomenon has been extensively investigated mathematically, numerically and experimentally. The latter has been the most fruitful so far, due to the complexity of the problem, for which the numerical and mathematical models are still incapable of accurately predicting the sloshing loads. The sloshing flows are usually characterised by the presence of multiphase interaction and turbulence. Reducing as much as possible the complexity of the sloshing problem without losing its essence is the main challenge of this phd thesis, where experimental work on selected canonical cases are presented and documented in order to better understand the phenomenon and to serve, in some cases, as an useful information for numerical validations. Liquid sloshing plays a key roll in the liquified natural gas (LNG) maritime transportation. The LNG market growth is more than three times the rated growth of the oil and traditional gas markets. Engineers working in research laboratories and companies are continuously looking for efficient and safe ways for containing, transferring and transporting the liquified gas. LNG carrying vessels (LNGC) have evolved from a few 75000 m3 vessels thirty years ago to a huge fleet of ships with a capacity of 140000 m3 nowadays and increasing number of 175000 m3 and 250000 m3 units. The concept of FLNG (Floating Liquified Natural Gas) has appeared recently. A FLNG unit is a high value-added vessel which can solve the problems of production, treatment, liquefaction and storage of the LNG because the vessel is equipped with a extraction and liquefaction facility. The LNG is transferred from the FLNG to the LNGC in open sea. The combination of partial fillings and wave induced motions may generate sloshing flows inside both the LNGC and the FLNG tanks. This work has dealt with sloshing problems from a experimental and statistical point of view. A series of tasks have been carried out: 1. A sloshing rig has been set up. It allows for testing tanks with one degree of freedom angular motion. The rig has been instrumented to measure motions, pressure and conduct video and image recording. 2. Regular motion impacts inside a rectangular section LNGC tank model have been studied, with forced motion tests, in order to characterise the phenomenon from a statistical point of view by assessing the repeatability and practical ergodicity of the problem. 3. The regular motion analysis has been extended to an irregular motion framework in order to reproduce more realistic scenarios. 4. The coupled motion of a single degree of freedom angular motion system excited by an external moment and affected by the fluid moment and the mechanical energy dissipation induced by sloshing inside the tank has been investigated. 5. The last task of the thesis has been to conduct an experimental investigation focused on the strong interaction between a sloshing flow in a rectangular section of a LNGC tank subjected to regular excitation and an elastic body clamped to the tank. It is thus a fluid structure interaction problem.

Fatiga en CFRP: Caracterización y Método Óptico para la Estimación del Daño

El desarrollo de nuevas estructuras aeroespaciales optimizadas, utilizan materiales compuestos, para los componentes críticos y subsistemas, principalmente polímeros reforzados con fibra de carbono (CFRP). Un conocimiento profundo del estado de daño por fatiga de estructuras de CFRP avanzado, es esencial para predecir la vida residual y optimizar los intervalos de inspección estructural, reparaciones y/o sustitución de componentes. Las técnicas actuales se basan principalmente en la medición de cargas estructurales a lo largo de la vida útil de la estructura mediante galgas extensométricas eléctricas. Con esos datos, se estima la vida a fatiga utilizando modelos de acumulación de daño. En la presente tesis, se evalúa la metodología convencional para la estimación de la vida a fatiga de un CFRP aeronáutico. Esta metodología está basada en la regla de acumulación de daño lineal de Palmgren-Miner, y es aplicada para determinar la vida a fatiga de estructuras sometidas a cargas de amplitud variable. Se ha realizado una campaña de ensayos con cargas de amplitud constante para caracterizar un CFRP aeronáutico a fatiga, obteniendo las curvas clásicas S-N, en diferentes relaciones de esfuerzo. Se determinaron los diagramas de vida constante, (CLD), también conocidos como diagramas de Goodman, utilizando redes neuronales artificiales debido a la ausencia de modelos coherentes para materiales compuestos. Se ha caracterizado la degradación de la rigidez debido al daño por fatiga. Se ha ensayado un segundo grupo de probetas con secuencias estandarizadas de cargas de amplitud variable, para obtener la vida a fatiga y la degradación de rigidez en condiciones realistas. Las cargas aplicadas son representativas de misiones de aviones de combate (Falstaff), y de aviones de transporte (Twist). La vida a fatiga de las probetas cicladas con cargas de amplitud variable, se comparó con el índice de daño teórico calculado en base a la regla de acumulación de daño lineal convencional. Los resultados obtenidos muestran predicciones no conservativas. Esta tesis también presenta el estudio y desarrollo, de una nueva técnica de no contacto para evaluar el estado de daño por fatiga de estructuras de CFRP por medio de cambios de los parámetros de rugosidad. La rugosidad superficial se puede medir fácilmente en campo con métodos sin contacto, mediante técnicas ópticas tales como speckle y perfilómetros ópticos. En el presente estudio, se han medido parámetros de rugosidad superficial, y el factor de irregularidad de la superficie, a lo largo de la vida de las probetas cicladas con cargas de amplitud constante y variable, Se ha obtenido una buena tendencia de ajuste al correlacionar la magnitud de la rugosidad y el factor de irregularidad de la superficie con la degradación de la rigidez de las probetas fatigadas. Estos resultados sugieren que los cambios en la rugosidad superficial medida en zonas estratégicas de componentes y estructuras hechas de CFRP, podrían ser indicativas del nivel de daño interno debido a cargas de fatiga. Los resultados también sugieren que el método es independiente del tipo de carga de fatiga que ha causado el daño. Esto último hace que esta técnica de medición sea aplicable como inspección para una amplia gama de estructuras de materiales compuestos, desde tanques presurizados con cargas de amplitud constante, estructuras aeronáuticas como alas y colas de aeronaves cicladas con cargas de amplitud variable, hasta aplicaciones industriales como automoción, entre otros. ABSTRACT New optimized aerospace structures use composite materials, mainly carbon fiber reinforced polymer composite (CFRP), for critical components and subsystems. A strong knowledge of the fatigue state of highly advanced (CFRP) structures is essential to predict the residual life and optimize intervals of structural inspection, repairs, and/or replacements. Current techniques are based mostly on measurement of structural loads throughout the service life by electric strain gauge sensors. These sensors are affected by extreme environmental conditions and by fatigue loads in such a way that the sensors and their systems require exhaustive maintenance throughout system life. In the present thesis, the conventional methodology based on linear damage accumulation rules, applied to determine the fatigue life of structures subjected to variable amplitude loads was evaluated for an aeronautical CFRP. A test program with constant amplitude loads has been performed to obtain the classical S-N curves at different stress ratios. Constant life diagrams, CLDs, where determined by means of Artificial Neural Networks due to the absence of consistent models for composites. The stiffness degradation due to fatigue damage has been characterized for coupons under cyclic tensile loads. A second group of coupons have been tested until failure with a standardized sequence of variable amplitude loads, representative of missions for combat aircraft (Falstaff), and representative of commercial flights (Twist), to obtain the fatigue life and the stiffness degradation under realistic conditions. The fatigue life of the coupons cycled with variable amplitude loads were compared to the theoretical damage index calculated based on the conventional linear damage accumulation rule. The obtained results show non-conservative predictions. This thesis also presents the evaluation of a new non-contact technique to evaluate the fatigue damage state of CFRP structures by means of measuring roughness parameters to evaluate changes in the surface topography. Surface roughness can be measured easily on field with non-contact methods by optical techniques such as speckle and optical perfilometers. In the present study, surface roughness parameters, and the surface irregularity factor, have been measured along the life of the coupons cycled with constant and variable amplitude loads of different magnitude. A good agreement has been obtained when correlating the magnitude of the roughness and the surface irregularity factor with the stiffness degradation. These results suggest that the changes on the surface roughness measured in strategic zones of components and structures made of CFRP, could be indicative of the level of internal damage due to fatigue loads. The results also suggest that the method is independent of the type of fatigue load that have caused the damage. It makes this measurement technique applicable for a wide range of inspections of composite materials structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures like wings and empennages, up to automotive and other industrial applications.

A time-domain finite element method for seakeeping and wave resistance problems

El objetivo de la tesis es la investigación de algoritmos numéricos para el desarrollo de herramientas numéricas para la simulación de problemas tanto de comportamiento en la mar como de resistencia al avance de buques y estructuras flotantes. La primera herramienta desarrollada resuelve el problema de difracción y radiación de olas. Se basan en el método de los elementos finitos (MEF) para la resolución de la ecuación de Laplace, así como en esquemas basados en MEF, integración a lo largo de líneas de corriente, y en diferencias finitas desarrollados para la condición de superficie libre. Se han desarrollado herramientas numéricas para la resolución de la dinámica de sólido rígido en sistemas multicuerpos con ligaduras. Estas herramientas han sido integradas junto con la herramienta de resolución de olas difractadas y radiadas para la resolución de problemas de interacción de cuerpos con olas. También se han diseñado algoritmos de acoplamientos con otras herramientas numéricas para la resolución de problemas multifísica. En particular, se han realizado acoplamientos con una herramienta numérica basada de cálculo de estructuras con MEF para problemas de interacción fluido-estructura, otra de cálculo de líneas de fondeo, y con una herramienta numérica de cálculo de flujos en tanques internos para problemas acoplados de comportamiento en la mar con “sloshing”. Se han realizado simulaciones numéricas para la validación y verificación de los algoritmos desarrollados, así como para el análisis de diferentes casos de estudio con aplicaciones diversas en los campos de la ingeniería naval, oceánica, y energías renovables marinas. ABSTRACT The objective of this thesis is the research on numerical algorithms to develop numerical tools to simulate seakeeping problems as well as wave resistance problems of ships and floating structures. The first tool developed is a wave diffraction-radiation solver. It is based on the finite element method (FEM) in order to solve the Laplace equation, as well as numerical schemes based on FEM, streamline integration, and finite difference method tailored for solving the free surface boundary condition. It has been developed numerical tools to solve solid body dynamics of multibody systems with body links across them. This tool has been integrated with the wave diffraction-radiation solver to solve wave-body interaction problems. Also it has been tailored coupling algorithms with other numerical tools in order to solve multi-physics problems. In particular, it has been performed coupling with a MEF structural solver to solve fluid-structure interaction problems, with a mooring solver, and with a solver capable of simulating internal flows in tanks to solve couple seakeeping-sloshing problems. Numerical simulations have been carried out to validate and verify the developed algorithms, as well as to analyze case studies in the areas of marine engineering, offshore engineering, and offshore renewable energy.

Tratamiento de vinazas provenientes de etanol en un reactor de lecho fluidizado inverso

En el estado de Veracruz, al sur de México, se ubican empresas dedicadas a la obtención de etanol a partir de melaza de azúcar de caña. Las más pequeñas, tienen una producción promedio de 20,000 L de alcohol/día. Los efluentes de la producción de etanol incluyen agua de enfriamiento de condensadores, agua del lavado de tanques de fermentación y vinazas, estas últimas son los efluentes más contaminantes en las destilerías, por su concentración de material orgánico biodegradable y no biodegradable. Las vinazas se generan en grandes volúmenes, produciéndose de 12 a 15 litros de vinazas por cada litro de alcohol destilado. Estos efluentes se caracterizan por tener altas temperaturas, pH ácido y una elevada concentración de DQO así como de sólidos totales. La determinación de la biodegradabilidad anaerobia de un agua residual, permite estimar la fracción de DQO que puede ser transformada potencialmente en metano y la DQO recalcitrante que queda en el efluente. Para el desarrollo de una prueba de biodegradabilidad, es importante considerar diversos factores relacionados con la composición del agua a tratar, composición de los lodos y las condiciones bajo las cuales se lleva a cabo la prueba. La digestión anaerobia de aguas residuales industriales es comúnmente usada en todo el mundo, ofrece significativas ventajas para el tratamiento de efluentes altamente cargados. Los sistemas anaerobios de tratamiento de aguas residuales industriales incluyen tecnologías con biopelículas, estos sistemas de tratamiento anaerobio con biopelícula son una tecnología bien establecida para el tratamiento de efluentes industriales. El Reactor de Lecho Fluidizado Inverso Anaerobio (LFI) ha sido diseñado para el tratamiento de aguas residuales de alta carga, teniendo como ventajas el empleo de un soporte que proporciona una gran superficie y un bajo requerimiento de energía para la fluidización del lecho. En el presente trabajo, se lleva a cabo el análisis de un proceso de producción de etanol, identificando a los efluentes que se generan en el mismo. Se encuentra que el efluente final está compuesto principalmente por las vinazas provenientes del proceso de destilación. En la caracterización de las vinazas provenientes del proceso de producción de etanol a partir de melaza de azúcar de caña, se encontraron valores promedio de DQO de 193.35 gDQO/L, para los sólidos totales 109.78 gST/L y pH de 4.64. Así mismo, en esta investigación se llevó a cabo una prueba de biodegradabilidad anaerobia, aplicada a la vinaza proveniente de la producción de etanol. En la caracterización de los lodos empleados en el ensayo se obtiene una Actividad Metanogénica Especifica de 0.14 g DQO/gSSV.d. El porcentaje de remoción de DQO de la vinaza fue de 62.7%, obteniéndose una k igual a 0.031 h-1 y una taza de consumo de sustrato de 1.26 gDQO/d. El rendimiento de metano fue de 0.19 LCH4/g DQOremovida y el porcentaje de biodegradabilidad de 54.1%. El presente trabajo también evalúa el desempeño de un LFI, empleando Extendospher® como soporte y tratando efluentes provenientes de la producción de etanol. El reactor se arrancó en batch y posteriormente se operó en continuo a diferentes Cargas Orgánicas Volumétricas de 0.5, 1.0, 3.3, 6.8 y 10.4 g DQO/L.d. Además, se evaluaron diferentes Tiempos de Residencia Hidráulica de 10, 5 y 1 días. El sistema alcanzó las siguientes eficiencias promedio de remoción de DQO: 81% para la operación en batch; 58, 67, 59 y 50 % para las cargas de 0.5, 1.0, 3.3, 6.8 g DQO/L.d respectivamente. Para la carga de 10.4 g DQO/L.d, la eficiencia promedio de remoción de DQO fue 38%, en esta condición el reactor presentó inestabilidad y disminución del rendimiento de metano. La generación de metano inició hasta los 110 días de operación del reactor a una carga de 1.0 g DQO/L.d. El sistema alcanzó un rendimiento de metano desde 0.15 hasta 0.34 LCH4/g DQO. Durante la operación del reactor a una carga constante de 6.4 g DQO/L.d, y un TRH de 1 día, se alcanzó una eficiencia promedio de remoción de DQO de 52%. In the state of Veracruz, to the south of Mexico, there are located companies dedicated to the production of ethanol from molasses of cane sugar. The smallest, have a average production of 20,000 L ethanol/day. The effluent of production of ethanol include water of condensers, water originated from the cleanliness of tanks of fermentation and vinasses, the above mentioned are more effluent pollutants in the distilleries, for the poor organic matter degradability. The vinasses are generated in high volumes, producing from 12 to 15 L of vinasses per every liter of distilled ethanol. These effluent are characterized by its high temperature, pH acid and a high concentration of DQO as well as high concentration of TS. The determination of the anaerobic degradability of a waste water, it allows to estimate the fraction of DQO that can be transformed potentially into methane and the recalcitrant DQO that stays in the effluent. For the development of degradability test, it is important to consider factors related to the composition of the water to be treated, composition of the sludge and the conditions under which the test is carried out. The anaerobic digestion of industrial wastes water is used commonly in the whole world, it offers significant advantages for the treatment of effluent highly loaded. The anaerobic treatment of industrial wastes water include technologies with biofilms, this anaerobic treatment whit biofilms systems, is a well-established technology for treatment of industrial effluents. The Anaerobic Inverse Fluidized Bed Reactor (IFBR) has been developed to provide biological treatment of high strength organic wastewater for their large specific surface and their low energy requirements for fluidization. In this work, there is carried out the analysis of a process of production of ethanol, identifying the effluent ones that are generated in the process. One determined that the effluent end is composed principally by the vinasses originated from the process of distillation. In the characterization of the vinasses originated from the process of production of ethanol from cane sugar molasses, there were average values of DQO of 193.35 gDQO/L, average values of solid of 109.78 gST/L and pH of 4.64. In this investigation there was carried out a anaerobic degradability test of the vinasses generated in the production of ethanol. In the characterization of the sludge used in the essay, the specific methanogenic activity (SMA) was 0.14 gDQO/gSSV.d. The average removal of DQO of the vinasses was 62.7 %, k equal to 0.031 h-1 was obtained one and a rate of removal substrate of 1.26 gDQO/d. The methane yield was 0.19 LCH4/gDQO removed and the anaerobic biodegradability was a 54.1 %. This study describes the performance of IFBR with Extendospher®, for the treatment of vinasses. The start-up was made in batch, increasing gradually the Organic Load Rate (OLR): 0.5, 1.0, 3.3, 6.8 and 10.4 g COD/L.d. Different Hydraulic Retention Times (HRT) were evaluated: 10, 5 and 1 days. During the operation in batch, the COD removal obtained was of 81 %, and for OLR of 0.5, 1.0, 3.3, 6.8 g COD/L.d the removal obtained was 58, 67, 59 and 50 % respectively. For a maximum OLR of 10.4 g COD/L.d, the COD removal was 38 %, and the system presented instability and decrease of the yield methane. The methane production initiated after 110 days of the start-up of the IFBR, to organic load rate of 1.0 g COD/L.d. The system reached values in the methane yield from 0.15 up to 0.34 LCH4/g CODremoved, for the different organic load rates. During the operation to a constant OLR of 6.4 g COD/L.d, and a HRT of 1 day, the Anaerobic Inverse Fluidized Bed Reactor reached a maximum efficiency of removal of 52 %.

Estudo experimental do comportamento à fratura frágil em aços estruturais ferríticos e aplicações à determinação da curva mestra.

Este trabalho apresenta uma investigação experimental sobre o comportamento à fratura frágil de aços estruturais ferríticos, ASTM A285 Gr C e ASTM A515 Gr 65. Os resultados deste trabalho ampliam a base de dados de propriedades mecânicas utilizadas nas análises de integridade de estruturas pressurizadas tais como vasos de pressão e tanques de armazenamento construídos com esta classe de material. O trabalho tem por objetivo também avaliar a aplicabilidade de corpos de prova de dimensões reduzidas, PCVN, na determinação da temperatura de referência, T0, por meio da metodologia da Curva Mestra, a qual define a dependência da tenacidade à fratura do material em função da temperatura. Os ensaios de tenacidade à fratura foram conduzidos utilizando-se corpos de prova solicitados em flexão três pontos com geometria SE(B), PCVN e PCVN com entalhe lateral, extraídos de chapas laminadas. Os resultados dos ensaios foram obtidos em termos de integral J no momento da instabilidade, denotados por Jc. Dados adicionais de resistência à tração e de Impacto Charpy convencional também foram obtidos para caracterizar o comportamento mecânico dos aços utilizados. Os resultados mostraram uma forte influência da geometria dos corpos de prova sobre os valores de Jc, evidenciada pela grande variação nos valores de tenacidade à fratura.

Observaciones preliminares del crecimiento de Paralichthys adspersus y presencia de infecciones por Vibrio spp. durante el ensayo de cultivo de Tumbes

La presente investigación es para evaluar la posibilidad de cultivo de Paralichthys adspersus (lenguado común) bajo las condiciones fisicoquímicas del agua del mar de la región de Tumbes. Luego de aclimatar 100 ejemplares de P. adspersus a la temperatura de 23,4 °C y 32 ‰ de salinidad, se distribuyó en dos tanques iguales de 1000 L a una densidad inicial de 50 ind./m3, realizando recambios diarios de 50 %, alimentados a saciedad durante todo el día con alimento balanceado de 42 % de proteínas (consumo total de alimento: 413 g). Mensualmente se muestreo el 100 % de los peces, determinando su tasa de crecimiento especifico, supervivencia y presencia de infecciones por Vibrio spp. La tasa de crecimiento específico durante esta experiencia fue de 0,41 %/día, la supervivencia luego de la aclimatación fue de 100 % hasta los 42 días de cultivo que alcanzó el 0 %, debido a la infestación por protozoarios parásitos del genero Amyloodinium en las branquias, descartando en todo momento la presencia de infecciones por Vibrio spp. La presente investigación permite precisar que P. adspersus se adapta a las condiciones fisicoquímicas de la región de Tumbes

Método híbrido para detecção e diagnóstico de falhas baseado em resíduos

The detection and diagnosis of faults, ie., find out how , where and why failures occur is an important area of study since man came to be replaced by machines. However, no technique studied to date can solve definitively the problem. Differences in dynamic systems, whether linear, nonlinear, variant or invariant in time, with physical or analytical redundancy, hamper research in order to obtain a unique solution . In this paper, a technique for fault detection and diagnosis (FDD) will be presented in dynamic systems using state observers in conjunction with other tools in order to create a hybrid FDD. A modified state observer is used to create a residue that allows also the detection and diagnosis of faults. A bank of faults signatures will be created using statistical tools and finally an approach using mean squared error ( MSE ) will assist in the study of the behavior of fault diagnosis even in the presence of noise . This methodology is then applied to an educational plant with coupled tanks and other with industrial instrumentation to validate the system.

Estudo comparativo de diferentes sistemas de injeção de vapor aplicados à remediação de solos contaminados por diesel

Among the potentially polluting economic activities that compromise the quality of soil and groundwater stations are fuel dealers. Leakage of oil derived fuels in underground tanks or activities improperly with these pollutants can contaminate large areas, causing serious environmental and toxicological problems. The number of gas stations grew haphazardly, without any kind of control, thus the environmental impacts generated by these enterprises grew causing pollution of soil and groundwater. Surfactants using various techniques have been proposed to remedy this kind of contamination. This study presents innovation as the application of different systems containing surfactant in the vapor phase and compares their diesel removal efficiencies of soil containing this contaminant. For this, a system that contains seven injection wells the following vaporized solutions: water, surfactant solution, microemulsion and nanoemulsion, The surfactants used were saponified coconut oil (OCS), in aqueous solution and an ethoxylated alcohol UNTL-90: aqueous solution , and nanoemulsion and microemulsion systems. Among the systems investigated, the nanoemulsion showed the highest efficiency, achieving 88% removal of residual phase diesel, the most ecologically and technically feasible by a system with lower content of active matter

Avaliação da variação sedimentológica em uma área da plataforma continental sob a atuação da indústria petrolífera

Petroleum exploration activity occurs on the offshore Potiguar Basin, from very shallow (2-3 m) until about 50 m water depth, extending from Alto de Touros (RN) to Alto de Fortaleza (CE). Take in account the biological importance and the heterogeneity of sediments on this area, it is necessary the understanding of the sedimentological dynamics, and mainly the changes generated by petroleum exploration to prevent possible damages to environment. Despite the intense activity of oil exploration in this area, research projects like these are still rare. In view to minimize this gap, this study was developed to evaluate sedimentological, mineralogical and geochemical changes in the vicinity of a exploration well, here designated as well A, located on the Middle continental shelf, near the transition to Outer shelf. The well selected for this study was the first one drilled with Riserless Mud Recovery technology (RMR) in Brazil. The main difference from this to the conventional method is the possibility of drilling phase I of the well with return of drilling material to the rig tank, minimizing fluid and gravel discharging around the vicinity, during this phase. Monitoring consisted of three surveys, first of them done before start drilling, the second one done 19 days after the end of drilling and the third one done one year after then. Comparison of the studied variables (calcium carbonate and organic matter content, sediment size, mineralogy and geochemistry) was done with their average, median and coefficient of variation values to understand the changes after drilling activity. Because operating company technical reasons, the well location was changed after the first survey (C1), resulting in a shift of the sampled area on the two last surveys (C2 e C3). Nevertheless, the acquired data presented a good correlation, with no loss to the mean goal of the study. The sedimentological, mineralogical and geochemical analyzes were done at Federal University of Rio Grande do Norte (UFRN). The results indicated a predominantly sandy environment along the three surveys. It was noticed that the first survey (C1), presented different values for all the studied variables than to the second (C2) and third (C3) surveys, which had similar values. Siliciclastic sediments are prevalent at all surveys, and quartz is the main component (more than 80%). Heavy minerals (garnet, turmaline, zircon and lmenite), rock fragments and mud aggregates also was described. Bioclastic sediments are dominated by coralline algae (more than 45%) and mollusks (more than 30%), followed by benthic foraminifera, bryozoans and worm tubes. More rarely was observed ostracoda and spike of calcareous sponge. Because the low changes of the sediments at the studied area and by the using of RMR method in the drilling, it was possible to conclude that drilling activity did not promote significant alteration on the local sediment cover. Changes in the studied variables before and after drilling activity could be influenced by the changing in the sampling area after survey 1 (C1).

Herpetofauna associada à bromélia rupícola, encholirium spectabile, no semiárido brasileiro: revisão da literatura, ecologia das espécies e comportamento de psychosaura agmosticha (squamata: mabuyidae)

Bromeliads are an important microhabitat for the herpetofauna, for being widely used as refuge from predators and their leaf architecture allows humidity maintenance and relatively constant temperature inside, setting a favorable environment for amphibians and reptiles, especially in areas under hydric stress. However, studies addressing this relationship are still incipient and more concentrated in fitotelmatas bromeliad. For non-fitotelmatas rupicolous bromeliads of the gender Encholirium, which develops into rocky outcrops and contains species of semi-arid regions such as the Caatinga, animal-plant relationships are almost unknown. In this context, this study aimed to know the herpetological fauna inhabitant of macambiras bromeliads, Encholirium spectabile, analyzing occupation and use of these bromeliads by different taxa, and the behavioral ecology of the lizard Psychosaura agmosticha, seeking to identify factors associated with this strict relationship in Caatinga. An extensive review of the world literature on the subject “lizards in bromeliads” subsidized this study from the ecological perspective of this association. The field work was carried out at Fazenda Tanques, municipality of Santa Maria / RN, mesoregion of Agreste Potiguar. The observations and/or data collection in daytime and in the evening was conducted monthly during three consecutive days, from January 2011 to August 2012, totaling 450 hour.man of sampling effort. Sixteen species were registered: six lizards (Mabuyidae, Tropiduridae, Gekkonidae and Phyllodactylidae Families), six snakes (Boidae and Dipsadidae Families) and four of amphibians of Hylidae Family. The effect of the forest edge on the distribution of species along the outcrop was significant, with most species found in outcrop edges. Significant difference was found between some pairs of species concerning use of bromeliads, and almost total niche overlap in the use of microhabitat. 62.5% of the species are nocturnal and use these plants for sheltering, breeding and feeding. Regarding the relations between 4 the lizard Psychosaura agmosticha and macambiras bromeliads, behaviors of thermoregulation and foraging in the dry and wet seasons were recorded. Activity periods were concentrated between 7 and 10 am and between 3 and 5 pm in both seasons, showing a clear bimodal pattern. The species basically used the green leaves and there were no significant differences between males and females in the use of bromeliads. Positive associations were found between body temperature and temperatures of bromeliads and air. This species spent 1.95% ± 3.8 of the time moving (PTM) and moved on average 0:36 ± 2.1 seconds per minute (MPM), with significant differences between the wet and dry to PTM, and between the average time of stop and average duration of movements, being considered a sedentary forager. Psychosaura agmosticha, in the study area, is bromelicolous and uses macambiras primarily for thermoregulation and foraging. The results of this study elevate the rupicolous bromeliads Encholirium spectabile as key elements for the maintenance of amphibians and reptiles associated with it, and a clear advantageous association for the conservation of the groups involved.

Ocorrência de leite instável na região semiárida do Rio Grande do Norte e sua correlação com a qualidade do leite

The unstable non acid milk (UNAM) is characterized by coagulation in the alcohol test and wanted acidity (14-18°D). Among Brazilian regions, the South and Southeast have the highest occurrence of LINA, which has been causing problems for both producers and for industries, due to the disposal or undervaluation of milk. In the Northeast there are few studies that indicate their occurrence and quality. The objective of this study was to identify the occurrence of unstable non-acid milk in the west and central mesoregions of Rio Grande do Norte, determine their physicochemical characteristics, test alcoholic graduations and evaluate their correlation with the quality of milk. 176 raw milk samples were analyzed in the period from September to December /2014 from 23 APASA’s cooling tanks, located in 7 cities of west and central mesoregions RN. The samples were collected in duplicate, one sample used for alcohol testing at 68, 72 and 76%, measurement of pH, acidity, electrical conductivity and boiling proof, made in LABOLEITE / UFRN; and the other sample containing Bronopol® preservative, was sent to the APCBRH (Cattle Breeders Association Paranaense Holstein) laboratory in Curitiba-PR, which were analyzed fat, protein, total solids, lactose, casein, urea nitrogen and somatic cell count. The test alcohol samples disapproved 31.82%, of which 30% proved to be non-acid, and 30% had high acidity. The samples were divided into three classes: Stable Milk, UNAM and acid milk. 3% Tukey test was used for comparison of stable milk components and UNAM and there was no significant difference between them. Both classes obtained averages within the standard required by IN 62. The average value of electric conductivity was 4.84 mS/cm for stable milk, 4.55 mS/cm for unstable and acid milk and 4.53 mS/cm for non-acid unstable milk. The electrical conductivity was positively correlated with alcohol stability of milk and negative correlation with acidity and pH. Could not observe direct relationship between the electrical conductivity and the somatic cell count.The boiling test was negative for all samples UNAM. It can be concluded that the incidence of UNAM in the studied region is low, although the predisposing factors such as heat stress, drought and nutritional deficiency. In conclusion, the UNAM has quality similar to stable milk, conform the norms required by Agriculture Ministry, and with adequate thermal stability, which proves that there is no reason to reject this milk by industry.

Caracterização da reprodução e ensaios de crescimento da Tilápia Moçambicana (Oreochromis mossambicus, Peters 1852)

Três grupos constituídos por indivíduos de tilápia da espécie Oreochromis mossambicus foram observados por um período de 6 meses e registado os seus comportamentos reprodutivos, número de fêmeas em incubação e o número de fry que nasceram durante este tempo. Cada grupo apresentava proporções sexuais distintas (macho:fêmea), nomeadamente, 1:3, 1:4 e 2:2. Após a evolução do estágio das fry a alevins, foram testados nestes indivíduos 3 dietas experimentais: a dieta RT (ração para tilápia), a dieta RD (dieta para douradas) e a Mix (uma mistura de 50% de cada uma das rações anteriormente referidas). Os alevins foram distribuídos em 9 tanques, 20 indivíduos/tanque, existindo três réplicas por dieta e todos se encontravam a uma temperatura de 28 ± 1ºC. Foram alimentados 3 vezes por dia durante 11 semanas, fazendo jejum 1 dia por semana. A cada 2 semanas, os indivíduos eram pesados e medidos e a quantidade de ração era ajustada de acordo com o seu crescimento. Como forma de se reduzir o stress neste procedimento de medição e pesagem, utilizaram-se três anestésicos a diferentes concentrações: MS-222 (0,15, 0,25 e 0,35ml L-1), óleo de cravo (0,10, 0,15 e 1,2ml L-1) e 2-fenoxietanol (0,40, 0,60, 0,80 e 1,00ml L-1). Registaram-se os tempos de indução e recuperação e avaliou-se qual o anestésico mais eficaz. No final do ensaio, os indivíduos foram mortos por choque térmico, filetados e sujeitados a estudos para avaliação do teor de proteína, lípidos, humidade e cinzas. No final de todo este trabalho experimental verificou-se que existiu reprodução nos Grupos 1 e 2 durante os 6 meses e que a melhor proporção sexual é 1:3 (macho:fêmea). Observou-se que as fêmeas que produzem mais posturas seguidas têm um menor número de fry por postura e as que fazem um maior intervalo de tempo entre cada postura, produzem posturas com um maior número de fry. Para qualquer uma destas opções das fêmeas, a taxa de mortalidade das fry é muito reduzida. No ensaio das dietas, os alevins aceitaram com boa aceitabilidade as três dietas mas com o decorrer do tempo, os indivíduos da dieta RD começaram a ganhar hemorragias em algumas partes do corpo. Não existiram diferenças significativas entre as dietas. A dieta Mix foi a que mostrou melhores resultados finais com um peso e comprimento máximos de 4,51 ± 3,39g e 3,36 ± 1,81cm, respetivamente. Para os valores de WG, SGR e FCR também não existiram diferenças significativas para as três iv dietas, sendo a dieta Mix a obter os valores máximos para WG (4,71g) e SGR (2,97% dia-1) mas com o FCR baixo (12,45 g/g). Para os resultados da composição química obtiveram-se diferenças estatisticamente significativas (P < 0,05) nos dados da proteína e humidade. A dieta RT foi a que apresentou um maior teor de proteína (18,53%) e os valores máximos para a humidade foram nas dietas RT (80.54%) e Mix (80,57%). Os lípidos e as cinzas não tiveram diferenças significativas e os valores máximos para estes dois parâmetros foram 1,38% e 1,50% na RT, respetivamente. Para os anestésicos estudados existiram diferenças significativas (P < 0,05) para os tempos de anestesia e recuperação pertencentes ao MS-222 e 2-fenoxietanol; o óleo de cravo apenas apresentou diferenças significativas no tempo de indução. As concentrações que mais eficazes se mostraram para anestesiar Tilápias Moçambicanas foram: 0,25ml L-1 para o MS-222, 0,10ml L-1 para o óleo de cravo e 0,80ml L-1 e 1,00ml L-1 para o 2-fenoxietanol. Os resultados deste trabalho sugerem que a reprodução de Tilápia Moçambicana se consegue com bastante sucesso quando se proporcionam condições ótimas, principalmente, a temperatura que é um dos fatores mais importantes; é uma espécie que aceita com facilidade variados tipos de rações; e os anestésicos utilizados mostraram-se eficazes a anestesiar os juvenis desta espécie apesar de ser necessário continuar o estudo com mais concentrações.