985 resultados para compressed natural gas
Resumo:
El mercado ibrico de futuros de energa elctrica gestionado por OMIP (Operador do Mercado Ibrico de Energia, Plo Portugus, con sede en Lisboa), tambin conocido como el mercado ibrico de derivados de energa, comenz a funcionar el 3 de julio de 2006. Se analiza la eficiencia de este mercado organizado, por lo que se estudia la precisin con la que sus precios de futuros predicen el precio de contado. En dicho mercado coexisten dos modos de negociacin: el mercado continuo (modo por defecto) y la contratacin mediante subasta. En la negociacin en continuo, las rdenes annimas de compra y de venta interactan de manera inmediata e individual con rdenes contrarias, dando lugar a operaciones con un nmero indeterminado de precios para cada contrato. En la negociacin a travs de subasta, un precio nico de equilibrio maximiza el volumen negociado, liquidndose todas las operaciones a ese precio. Adicionalmente, los miembros negociadores de OMIP pueden liquidar operaciones Over-The-Counter (OTC) a travs de la cmara de compensacin de OMIP (OMIClear). Las cinco mayores empresas espaolas de distribucin de energa elctrica tenan la obligacin de comprar electricidad hasta julio de 2009 en subastas en OMIP, para cubrir parte de sus suministros regulados. De igual manera, el suministrador de ltimo recurso portugus mantuvo tal obligacin hasta julio de 2010. Los precios de equilibrio de esas subastas no han resultado ptimos a efectos retributivos de tales suministros regulados dado que dichos precios tienden a situarse ligeramente sesgados al alza. La prima de riesgo ex-post, definida como la diferencia entre los precios a plazo y de contado en el periodo de entrega, se emplea para medir su eficiencia de precio. El mercado de contado, gestionado por OMIE (Operador de Mercado Ibrico de la Energa, conocido tradicionalmente como OMEL), tiene su sede en Madrid. Durante los dos primeros aos del mercado de futuros, la prima de riesgo media tiende a resultar positiva, al igual que en otros mercados europeos de energa elctrica y gas natural. En ese periodo, la prima de riesgo ex-post tiende a ser negativa en los mercados de petrleo y carbn. Los mercados de energa tienden a mostrar niveles limitados de eficiencia de mercado. La eficiencia de precio del mercado de futuros aumenta con el desarrollo de otros mecanismos coexistentes dentro del mercado ibrico de electricidad (conocido como MIBEL) es decir, el mercado dominante OTC, las subastas de centrales virtuales de generacin conocidas en Espaa como Emisiones Primarias de Energa, y las subastas para cubrir parte de los suministros de ltimo recurso conocidas en Espaa como subastas CESUR y con una mayor integracin de los mercados regionales europeos de energa elctrica. Se construye un modelo de regresin para analizar la evolucin de los volmenes negociados en el mercado continuo durante sus cuatro primeros aos como una funcin de doce indicadores potenciales de liquidez. Los nicos indicadores significativos son los volmenes negociados en las subastas obligatorias gestionadas por OMIP, los volmenes negociados en el mercado OTC y los volmenes OTC compensados por OMIClear. El nmero de creadores de mercado, la incorporacin de agentes financieros y compaas de generacin pertenecientes a grupos integrados con suministradores de ltimo recurso, y los volmenes OTC compensados por OMIClear muestran una fuerte correlacin con los volmenes negociados en el mercado continuo. La liquidez de OMIP est an lejos de los niveles alcanzados por los mercados europeos ms maduros (localizados en los pases nrdicos (Nasdaq OMX Commodities) y Alemania (EEX)). El operador de mercado y su cmara de compensacin podran desarrollar acciones eficientes de marketing para atraer nuevos agentes activos en el mercado de contado (p.ej. industrias consumidoras intensivas de energa, suministradores, pequeos productores, compaas energticas internacionales y empresas de energas renovables) y agentes financieros, captar volmenes del opaco OTC, y mejorar el funcionamiento de los productos existentes an no lquidos. Resultara de gran utilidad para tales acciones un dilogo activo con todos los agentes (participantes en el mercado, operador de mercado de contado, y autoridades supervisoras). Durante sus primeros cinco aos y medio, el mercado continuo presenta un crecimento de liquidez estable. Se mide el desempeo de sus funciones de cobertura mediante la ratio de posicin neta obtenida al dividir la posicin abierta final de un contrato de derivados mensual entre su volumen acumulado en la cmara de compensacin. Los futuros carga base muestran la ratio ms baja debido a su buena liquidez. Los futuros carga punta muestran una mayor ratio al producirse su menor liquidez a travs de contadas subastas fijadas por regulacin portuguesa. Las permutas carga base liquidadas en la cmara de compensacin ubicada en Madrid MEFF Power, activa desde el 21 de marzo de 2011 muestran inicialmente valores altos debido a bajos volmenes registrados, dado que esta cmara se emplea principalmente para vencimientos pequeos (diario y semanal). Dicha ratio puede ser una poderosa herramienta de supervisin para los reguladores energticos cuando accedan a todas las transacciones de derivados en virtud del Reglamento Europeo sobre Integridad y Transparencia de los Mercados de Energa (REMIT), en vigor desde el 28 de diciembre de 2011. La prima de riesgo ex-post tiende a ser positiva en todos los mecanismos (futuros en OMIP, mercado OTC y subastas CESUR) y disminuye debido a la curvas de aprendizaje y al efecto, desde el ao 2011, del precio fijo para la retribucin de la generacin con carbn autctono. Se realiza una comparativa con los costes a plazo de generacin con gas natural (diferencial clean spark spread) obtenido como la diferencia entre el precio del futuro elctrico y el coste a plazo de generacin con ciclo combinado internalizando los costes de emisin de CO2. Los futuros elctricos tienen una elevada correlacin con los precios de gas europeos. Los diferenciales de contratos con vencimiento inmediato tienden a ser positivos. Los mayores diferenciales se dan para los contratos mensuales, seguidos de los trimestrales y anuales. Los generadores elctricos con gas pueden maximizar beneficios con contratos de menor vencimiento. Los informes de monitorizacin por el operador de mercado que proporcionan transparencia post-operacional, el acceso a datos OTC por el regulador energtico, y la valoracin del riesgo regulatorio pueden contribuir a ganancias de eficiencia. Estas recomendaciones son tambin vlidas para un potencial mercado ibrico de futuros de gas, una vez que el hub ibrico de gas actualmente en fase de diseo, con reuniones mensuales de los agentes desde enero de 2013 en el grupo de trabajo liderado por el regulador energtico espaol est operativo. El hub ibrico de gas proporcionar transparencia al atraer ms agentes y mejorar la competencia, incrementando su eficiencia, dado que en el mercado OTC actual no se revela precio alguno de gas. ABSTRACT The Iberian Power Futures Market, managed by OMIP (Operador do Mercado Ibrico de Energia, Plo Portugus, located in Lisbon), also known as the Iberian Energy Derivatives Market, started operations on 3 July 2006. The market efficiency, regarding how well the future price predicts the spot price, is analysed for this energy derivatives exchange. There are two trading modes coexisting within OMIP: the continuous market (default mode) and the call auction. In the continuous trading, anonymous buy and sell orders interact immediately and individually with opposite side orders, generating trades with an undetermined number of prices for each contract. In the call auction trading, a single price auction maximizes the traded volume, being all trades settled at the same price (equilibrium price). Additionally, OMIP trading members may settle Over-the-Counter (OTC) trades through OMIP clearing house (OMIClear). The five largest Spanish distribution companies have been obliged to purchase in auctions managed by OMIP until July 2009, in order to partly cover their portfolios of end users regulated supplies. Likewise, the Portuguese last resort supplier kept that obligation until July 2010. The auction equilibrium prices are not optimal for remuneration purposes of regulated supplies as such prices seem to be slightly upward biased. The ex-post forward risk premium, defined as the difference between the forward and spot prices in the delivery period, is used to measure its price efficiency. The spot market, managed by OMIE (Market Operator of the Iberian Energy Market, Spanish Pool, known traditionally as OMEL), is located in Madrid. During the first two years of the futures market, the average forward risk premium tends to be positive, as it occurs with other European power and natural gas markets. In that period, the ex-post forward risk premium tends to be negative in oil and coal markets. Energy markets tend to show limited levels of market efficiency. The price efficiency of the Iberian Power Futures Market improves with the market development of all the coexistent forward contracting mechanisms within the Iberian Electricity Market (known as MIBEL) namely, the dominant OTC market, the Virtual Power Plant Auctions known in Spain as Energy Primary Emissions, and the auctions catering for part of the last resort supplies known in Spain as CESUR auctions and with further integration of European Regional Electricity Markets. A regression model tracking the evolution of the traded volumes in the continuous market during its first four years is built as a function of twelve potential liquidity drivers. The only significant drivers are the traded volumes in OMIP compulsory auctions, the traded volumes in the OTC market, and the OTC cleared volumes by OMIClear. The amount of market makers, the enrolment of financial members and generation companies belonging to the integrated group of last resort suppliers, and the OTC cleared volume by OMIClear show strong correlation with the traded volumes in the continuous market. OMIP liquidity is still far from the levels reached by the most mature European markets (located in the Nordic countries (Nasdaq OMX Commodities) and Germany (EEX)). The market operator and its clearing house could develop efficient marketing actions to attract new entrants active in the spot market (e.g. energy intensive industries, suppliers, small producers, international energy companies and renewable generation companies) and financial agents as well as volumes from the opaque OTC market, and to improve the performance of existing illiquid products. An active dialogue with all the stakeholders (market participants, spot market operator, and supervisory authorities) will help to implement such actions. During its firs five and a half years, the continuous market shows steady liquidity growth. The hedging performance is measured through a net position ratio obtained from the final open interest of a month derivatives contract divided by its accumulated cleared volume. The base load futures in the Iberian energy derivatives exchange show the lowest ratios due to good liquidity. The peak futures show bigger ratios as their reduced liquidity is produced by auctions fixed by Portuguese regulation. The base load swaps settled in the clearing house located in Spain MEFF Power, operating since 21 March 2011, with a new denomination (BME Clearing) since 9 September 2013 show initially large values due to low registered volumes, as this clearing house is mainly used for short maturity (daily and weekly swaps). The net position ratio can be a powerful oversight tool for energy regulators when accessing to all the derivatives transactions as envisaged by European regulation on Energy Market Integrity and Transparency (REMIT), in force since 28 December 2011. The ex-post forward risk premium tends to be positive in all existing mechanisms (OMIP futures, OTC market and CESUR auctions) and diminishes due to the learning curve and the effect since year 2011 of the fixed price retributing the indigenous coal fired generation. Comparison with the forward generation costs from natural gas (clean spark spread) obtained as the difference between the power futures price and the forward generation cost with a gas fired combined cycle plant taking into account the CO2 emission rates is also performed. The power futures are strongly correlated with European gas prices. The clean spark spreads built with prompt contracts tend to be positive. The biggest clean spark spreads are for the month contract, followed by the quarter contract and then by the year contract. Therefore, gas fired generation companies can maximize profits trading with contracts of shorter maturity. Market monitoring reports by the market operator providing post-trade transparency, OTC data access by the energy regulator, and assessment of the regulatory risk can contribute to efficiency gains. The same recommendations are also valid for a potential Iberian gas futures market, once an Iberian gas hub currently in a design phase, with monthly meetings amongst the stakeholders in a Working Group led by the Spanish energy regulatory authority since January 2013 is operating. The Iberian gas hub would bring transparency attracting more shippers and improving competition and thus its efficiency, as no gas price is currently disclosed in the existing OTC market.
Resumo:
Actualmente existe un gran inters orientado hacia el mercado del gas natural. Son muchas las razones por las que este combustible se posiciona como uno de los ms importantes dentro del panorama energtico mundial. Adems de que salvara el hueco dejado por el carbn y el petrleo, supone una alternativa mucho ms limpia que se podra desarrollar an ms tanto a nivel domstico, industrial como en el mundo de los transportes. La industria del gas natural est cambiando rpidamente fundamentalmente por la aparicin del gas no convencional y sus tcnicas de extraccin. Por lo que se est produciendo un cambio en la economa de la produccin de gas as como en la dinmica y los movimientos del GNL a lo largo de todo el planeta. El propsito de este estudio es enfocar el estado del sector y mercado del gas natural en todo el mundo y de esta forma subrayar las principales regiones que marcan la tendencia general de los precios de todo el planeta. Adems, este trabajo reflejar los pronsticos esperados para los prximos aos as como un resumen de las tendencias que se han seguido hasta el momento. Particularmente, se centrar la atencin en el movimiento hacia los sistemas basados en forma de hub que comenzaron en EE.UU. y que llegaron a Reino Unido y al continente Europeo a principios del S.XX. Esta tendencia es la que se pretende implantar en Espaa con el fin de conseguir una mayor competitividad, flexibilidad y liquidez en los precios y en el sistema gasista. De esta forma, poco a poco se ir construyendo la estructura hacia un Mercado nico Europeo que es el objetivo final que plantean los organismos de los estados miembros. Sin embargo, para la puesta en marcha de este nuevo modelo es necesario realizar una serie de cambios en el sistema como la modificacin de la Ley de Hidrocarburos, la designacin de un Operador de Mercado, elaboracin de una serie de reglas para regular el mercado as como fomentar la liquidez del mercado. Cuando tenga lugar el cambio regulatorio, la liquidez del sistema espaol incrementar y se dar la oportunidad de crear nuevas formas para balancear las carteras de gas y establecer nuevas estrategias para gestionar el riesgo. No obstante, antes de que se hagan efectivos los cambios en la legislacin, se implantara uno de los modelos planteados en el Gas Target Model, el denominado Modelo de Asignacin de Capacidad Implcita. La introduccin de este modelo sera un primer paso para la integracin de un mercado de gas sin la necesidad de afrontar un cambio legislativo, lo que servira de VIII impulso para alcanzar el Modelo de rea de Mercado que sera el mejor para el sistema gasista espaol y se conectara ampliamente con el resto de mercados europeos. Las conclusiones del estudio en relacin a la formacin del nuevo modelo en forma de hub plantean la necesidad de aprovechar al mximo la nueva situacin y conseguir implantar el hub lo antes posible para poder dotar al sistema de mayor competencia y liquidez. Adems, el sistema espaol debe aprovechar su gran capacidad y moderna infraestructura para convertir al pas en la entrada de gas del suroeste de Europa ampliando as la seguridad de suministro de los pases miembros. Otra conclusin que se puede extraer del informe es la necesidad de ampliar el ndice de penetracin del gas en Espaa e incentivar el consumo frente a otros combustibles fsiles como el carbn y el petrleo. Esto situara al gas natural como la principal energa de respaldo con respecto a las renovables y permitira disminuir los precios del kilovatio hora del gas natural. El estudio y anlisis de la dinmica que se viene dando en la industria del gas en el mundo es fundamental para poder anticiparse y planear las mejores estrategias frente a los cambios que poco a poco irn modificando el sector y el mercado gasista. ABSTRACT There is a great deal of focus on the natural gas market at the moment. Whether you view natural gas as bridging the gap between coal/oil and an altogether cleaner solution yet to be determined, or as a destination fuel which will be used not only for heating and gas fired generation but also as transportation fuel, there is no doubt that natural gas will have an increasingly important role to play in the global energy landscape. The natural gas industry is changing rapidly, as shale gas exploration changes the economics of gas production and LNG connects regions across the globe. The purpose of this study is to outline the present state of the global gas industry highlighting the differing models around the world. This study will pay particular attention to the move towards hub based pricing that has taken hold first in the US and over the past decade across the UK and Continental Europe. In the coming years the Spanish model will move towards hub based pricing. As gas market regulatory change takes hold, liquidity in the Spanish gas market will increase, bringing with it new ways to balance gas portfolios and placing an increasing focus on managing price risk. This study will in turn establish the links between the changes that have taken place in other markets as a way to better understanding how the Spanish market will evolve in the coming years.
Resumo:
Current social demand for more environmentally-friendly fuels environment has imposed stringent emissions standards infectious greenhouse affecting all means of transport, including maritime. A few free zones emissions (ECA) in waters around the world have been established. This has driven to the Liquefied Natural Gas (LNG) as the fuel of the future for ships to comply with emissions laid down by the Convention International Prevention of the Pollution from Ships (MARPOL). The present work proposes the installation of a LNG station for ships in the future regasification plant of Granadilla (Santa Cruz de Tenerife). The work has understood the design and sizing of the receiving of the regasification plant terminal pipelines, as well as pipes for the LNG station. La demanda social actual por combustibles ms respetuosos con el medio ambiente ha impuesto unas estrictas normas de emisiones de gases infecto invernadero que afectan a todos los medios de transporte, incluido el martimo. Se han establecido unas zonas libres de emisiones (ECA) en aguas de todo el mundo. Esto ha impulsado al Gas Natural Licuado (GNL) como el combustible del futuro para buques para cumplir con las emisiones fijadas por la Convencin Internacional de Prevencin de la Contaminacin de Barcos (MARPOL). El presente trabajo propone la instalacin de una gasinera para buques en la futura planta de regasificacin de Granadilla (Santa Cruz de Tenerife). El trabajo ha comprendido el diseo y dimensionamiento de las tuberas de la terminal de recepcin de la planta de regasificacin, as como las tuberas para la gasinera.
Resumo:
The energetic performance of landfill biogas (LB) and biodigester biogas (BB) from municipal waste was examined in consumption tests. These tests were performed in situ at a gas generation plant associated with a landfill facility in Madrid (Spain) and following the standard UNE-EN 30-2-1 (1999). The jets of a domestic cooker commonly used for natural gas (NG) or liquefied petroleum gas (LPG) were modified to operate with the biogases produced at the facility. The working pressures best suited to the tested gases, i.e., to avoid flashback and flame lift, and to ensure the stability and correct functioning of the flame during combustion, were determined by trial and error. Both biogases returned optimum energetic performance for the transfer of heat to water in a metallic recipient (as required by the above standard) at a supply pressure of 10 mbar. Domestic cookers are normally supplied with NG at a pressure of 20 mbar, at which pressure the energetic performance of G20 reference gas was higher than that of both biogases (52.84% compared to 38.06% and 49.77% respectively). Data concerning these issues involving also unexplored feedstock are required for the correct conversions of domestic cookers in order to avoid risks of serious personal injuries or property damages.
Resumo:
This paper examined the potentialities of Life Cycle Assessment (LCA) as instrument for policy-support. To this respect, the adoption of an initiative within the Madrid Air Quality Plan (AQP) 20112015 regarding the substitution of diesel taxis with hybrid, natural gas and LPG alternatives was studied. Four different scenarios were elaborated, a business-as-usual scenario (BAU), the scenario of the AQP, and two extreme-situation scenarios: all-diesel (ADI) and all-ecologic (AEC). Impacts were characterized according to the ILCD methodology, focusing especially on climate change (CC) and photochemical ozone formation (PO). SimaPro 7.3 was used as analysis and inventory-construction tool. The results indicate that the shift to ecologic alternatives reduced impacts, especially those related to CC and PO. For the complete life cycle, reductions of 13% (CC) and 25% (PO) were observed for AQP against BAU (CC:1365 GgCO2, PO:13336 MgNMVOC). Deeper reductions were observed for AEC (CC:34%, PO:59%), while ADI produced slight increases in impacts if against BAU. The analysis of the use-phase revealed that the central and highest speed zones of the city benefit from the adoption of AQP. This is especially evident in zone 7, with reductions of 16% in CC and 31% in PO respectively against BAU (CCzone1:3443 kgCO2/vehkm, POzone7:11.1 kgNMVOC/vehkm).
Resumo:
In this Project, a preliminary design of a dehydration unit for domestic gas will be outlined. This unit that is the subject of the study belongs to a project named Gorgon. Such project is currently been developed by Chevron in Barrow Island, Australia. In order to conduct a proper design of such unit, characteristics of the natural gas that is being extracted shall be detailed, as well as proper specifications of the pipeline to which the gas will supply. After this, different techniques for dehydrating the gas are evaluated; the technique that fits better this Project is absorption by glycol and following such assumption will be chosen as the best one. More accurately, the most suitable type of glycol for this particular unit is triethilene glycol, considering that it fits better the conditions of the project. Once the method is chosen, a simulation shall be undertaken with the purpose of determining the number of stages required for the correct functioning of the unit, the glycol rate and its purity. Besides, it is needed to estimate its pressure and temperature and the dimensions that would then follow. In addition, pressures and temperatures are estimated at the regeneration glycol process, together with dimensions of some units. Furthermore, it is necessary to estimate pressure and temperature at which natural gas is leaving the dehydration unit. In addition, both compression needed to secure the flux at the pipeline and the resulting pressure at the reception shall be studied. Finally, an economic study is carried out in order to conclude whether or not this specific Project is feasible.
Resumo:
En este proyecto se ha realizado el dimensionamiento de los equipos bsicos de una planta de licuacin de gas natural cuya localizacin es Texas, EEUU. La capacidad de la planta es de 1 MTPA y funciona mediante un proceso de licuefaccin de licencia Prico. Su objetivo fundamental es servir de apoyo en las puntas de consumo de gas natural (el cual vara considerablemente segn la poca del ao) mediante reinyeccin del producto en los gaseoductos en los momentos de mayor demanda o incluso mediante su transporte en camiones cisterna. El proyecto ha comprendido el anlisis del proceso Prico con su diagrama de flujo, el dimensionamiento de los intercambiadores de calor (carcasa y tubos y plate-fin), seleccin de los equipos rotativos, simulacin del proceso y dimensionamiento de tuberas, as como un pequeo estudio econmico. Abstract In this project, sizing of main equipment of a natural gas liquefaction plant has been developed. The plant is located in Texas, EEUU. Plant capacity is 1 MTPA and is designed to produce LNG by using a Prico liquefaction process. The main objective of the designed plant is to support the peaks of consumption of natural gas (which varies considerably along the year) by liquefying, storing and reinjecting the natural gas in the pipelines or even using tanker trucks to take LNG to consumers. The project includes the analysis of the Prico process flow diagram, sizing of the heat exchangers (shell & tube and plate-fin), selection of rotatory equipment, process simulation and pipe sizing, and a viability analysis.
Resumo:
En hidrodinmica, el fenmeno 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 cuestin experimenta violentos movimientos con importantes deformaciones de su superficie libre. La dinmica del fluido puede llegar a generar cargas hidrodinmicas considerables las cuales pueden afectar la integridad estructural y/o comprometer la estabilidad del vehculo que transporta dicho contenedor. El fenmeno de Sloshing ha sido extensivamente investigado matemtica, numrica y experimentalmente, siendo el enfoque experimental el ms usado debido a la complejidad del problema, para el cual los modelos matemticos y de simulacin son aun incapaces de predecir con suficiente rapidez y precisin las cargas debidas a dicho fenmeno. El flujo generado por el Sloshing usualmente se caracteriza por la presencia de un fluido multifase (gas-liquido) y turbulencia. Reducir al mximo posible la complejidad del fenmeno de Sloshing sin perder la esencia del problema es el principal reto de esta tesis doctoral, donde un trabajo experimental enfocado en casos cannicos de Sloshing es presentado y documentado con el objetivo de aumentar la comprensin de dicho fenmeno y por tanto intentar proveer informacin valiosa para validaciones de cdigos numricos. El fenmeno de Sloshing juega un papel importante en la industria del transporte martimo de gas licuado (LNG). El mercado de LNG en los ltimos aos ha reportado un crecimiento hasta tres veces mayor al de los mercados de petrleo y gas convencionales. Ingenieros en laboratorios de investigacin e ingenieros adscritos a la industria del LNG trabajan continuamente buscando soluciones econmicas y seguras para contener, transferir y transportar grandes volmenes de LNG. Los buques transportadores de LNG (LNGC) han pasado de ser unos pocos buques con capacidad de 75000 m3 hace unos treinta aos, a una amplia flota con una capacidad de 140000 m3 actualmente. En creciente nmero, hoy da 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 aadido que solventa los problemas de extraccin, licuefaccin y almacenamiento del LNG, ya que cuenta con equipos de extraccin y licuefaccin a bordo, eliminando por tanto las tareas de transvase de las estaciones de licuefaccin 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 combinacin con oleaje durante las operaciones de trasvase inducen movimientos en los buques que generan por tanto el fenmeno 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 estadstico, para ello una serie de tareas, descritas a continuacin, 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, as como la grabacin de imgenes y videos. 2. Los impactos de olas generadas dentro de una seccin rectangular de un LNGC sujeto a movimientos regulares forzados han sido estudiados mediante la caracterizacin del fenmeno desde un punto de vista estadstico 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 ms realstico mediante el uso de movimientos irregulares forzados. 4. El acoplamiento del Sloshing generado por el fluido en movimiento dentro del tanque LNGC y la disipacin de la energa mecnica de un sistema no forzado de un grado de libertad (movimiento angular) sujeto a una excitacin externa ha sido investigado. 5. En la ltima seccin de esta tesis doctoral, la interaccin entre el Sloshing generado dentro en una seccin rectangular de un tanque LNGC sujeto a una excitacin regular y un cuerpo elstico solidario al tanque ha sido estudiado. Dicho estudio corresponde a un problema de interaccin 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.
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The environmental performance of a 50 MW parabolic trough Concentrated Solar Power (CSP) plant hybridised with different fuels was determined using a Life Cycle Assessment methodology. Six different scenarios were investigated, half of which involved hybridisation with fossil fuels (natural gas, coal and fuel oil), and the other three involved hybridisation with renewable fuels (wheat straw, wood pellets and biogas). Each scenario was compared to a solar-only operation. Nine different environmental categories as well as the Cumulative Energy Demand and the Energy Payback Time (EPT) were evaluated using Simapro software for 1 MWh of electricity produced. The results indicate a worse environmental performance for a CSP plant producing 12% of the electricity from fuel than in a solar-only operation for every indicator, except for the eutrophication and toxicity categories, whose results for the natural gas scenario are slightly better. In the climate change category, the results ranged between 26.9 and 187 kg CO2 eq/MWh, where a solar-only operation had the best results and coal hybridisation had the worst. Considering a weighted single score indicator, the environmental impact of the renewable fuels scenarios is approximately half of those considered in fossil fuels, with the straw scenario showing the best results, and the coal scenario the worstones. EPT for solar-only mode is 1.44 years, while hybridisation scenarios EPT vary in a range of 1.72 -1.83 years for straw and pellets respectively. The fuels with more embodied energy are biomethane and wood pellets.
Resumo:
El 10 de octubre de 2008 la Organizacin Martima Internacional (OMI) firm una modificacin al Anexo VI del convenio MARPOL 73/78, por la que estableci una reduccin progresiva de las emisiones de xidos de azufre (SOx) procedentes de los buques, una reduccin adicional de las emisiones de xidos de nitrgeno (NOx), as como lmites en las emisiones de dixido de Carbono (CO2) procedentes de los motores marinos y causantes de problemas medioambientales como la lluvia cida y efecto invernadero. Centrndonos en los lmites sobre las emisiones de azufre, a partir del 1 de enero de 2015 esta normativa obliga a todos los buques que naveguen por zonas controladas, llamadas Emission Control Area (ECA), a consumir combustibles con un contenido de azufre menor al 0,1%. A partir del 1 de enero del ao 2020, o bien del ao 2025, si la OMI decide retrasar su inicio, los buques debern consumir combustibles con un contenido de azufre menor al 0,5%. De igual forma que antes, el contenido deber ser rebajado al 0,1%S, si navegan por el interior de zonas ECA. Por su parte, la Unin Europea ha ido ms all que la OMI, adelantando al ao 2020 la aplicacin de los lmites ms estrictos de la ley MARPOL sobre las aguas de su zona econmica exclusiva. Para ello, el 21 de noviembre de 2013 firm la Directiva 2012 / 33 / EU como adenda a la Directiva de 1999. Tengamos presente que la finalidad de estas nuevas leyes es la mejora de la salud pblica y el medioambiente, produciendo beneficios sociales, en forma de reduccin de enfermedades, sobre todo de tipo respiratorio, a la vez que se reduce la lluvia cida y sus nefastas consecuencias. La primera pregunta que surge es cul es el combustible actual de los buques y cul ser el que tengan que consumir para cumplir con esta Regulacin? Pues bien, los grandes buques de navegacin internacional consumen hoy en da fuel oil con un nivel de azufre de 3,5%. Existen fueles con un nivel de azufre de 0,5%S? Como hemos concluido en el captulo 4, para las empresas petroleras, la produccin de fuel oil como combustible marino es tratada como un subproducto en su cesta de productos refinados por cada barril de Brent, ya que la demanda de fuel respecto a otros productos est bajando y adems, el margen de beneficio que obtienen por la venta de otros productos petrolferos es mayor que con el fuel. As, podemos decir que las empresas petroleras no estn interesadas en invertir en sus refineras para producir estos fueles con menor contenido de azufre. Es ms, en el caso de que alguna compaa decidiese invertir en producir un fuel de 0,5%S, su precio debera ser muy similar al del gasleo para poder recuperar las inversiones empleadas. Por lo tanto, el nico combustible que actualmente cumple con los nuevos niveles impuestos por la OMI es el gasleo, con un precio que durante el ao 2014 estuvo a una media de 307 USD/ton ms alto que el actual fuel oil. Este mayor precio de compra de combustible impactar directamente sobre el coste del trasporte martimo. La entrada en vigor de las anteriores normativas est suponiendo un reto para todo el sector martimo. Ante esta realidad, se plantean diferentes alternativas con diferentes implicaciones tcnicas, operativas y financieras. En la actualidad, son tres las alternativas con mayor aceptacin en el sector. La primera alternativa consiste en no hacer nada y simplemente cambiar el tipo de combustible de los grandes buques de fuel oil a gasleo. Las segunda alternativa es la instalacin de un equipo scrubber, que permitira continuar con el consumo de fuel oil, limpiando sus gases de combustin antes de salir a la atmsfera. Y, por ltimo, la tercera alternativa consiste en el uso de Gas Natural Licuado (GNL) como combustible, con un precio inferior al del gasleo. Sin embargo, an existen importantes incertidumbres sobre la evolucin futura de precios, operacin y mantenimiento de las nuevas tecnologas, inversiones necesarias, disponibilidad de infraestructura portuaria e incluso el desarrollo futuro de la propia normativa internacional. Estas dudas hacen que ninguna de estas tres alternativas sea unnime en el sector. En esta tesis, tras exponer en el captulo 3 la regulacin aplicable al sector, hemos investigado sus consecuencias. Para ello, hemos examinado en el captulo 4 si existen en la actualidad combustibles marinos que cumplan con los nuevos lmites de azufre o en su defecto, cul sera el precio de los nuevos combustibles. Partimos en el captulo 5 de la hiptesis de que todos los buques cambian su consumo de fuel oil a gasleo para cumplir con dicha normativa, calculamos el incremento de demanda de gasleo que se producira y analizamos las consecuencias que este hecho tendra sobre la produccin de gasleos en el Mediterrneo. Adicionalmente, calculamos el impacto econmico que dicho incremento de coste producir sobre sector exterior de Espaa. Para ello, empleamos como base de datos el sistema de control de trfico martimo Authomatic Identification System (AIS) para luego analizar los datos de todos los buques que han hecho escala en algn puerto espaol, para as calcular el extra coste anual por el consumo de gasleo que sufrir el transporte martimo para mover todas las importaciones y exportaciones de Espaa. Por ltimo, en el captulo 6, examinamos y comparamos las otras dos alternativas al consumo de gasleo -scrubbers y propulsin con GNL como combustible- y, finalmente, analizamos en el captulo 7, la viabilidad de las inversiones en estas dos tecnologas para cumplir con la regulacin. En el captulo 5 explicamos los numerosos mtodos que existen para calcular la demanda de combustible de un buque. La metodologa seguida para su clculo ser del tipo bottom-up, que est basada en la agregacin de la actividad y las caractersticas de cada tipo de buque. El resultado est basado en la potencia instalada de cada buque, porcentaje de carga del motor y su consumo especfico. Para ello, analizamos el nmero de buques que navegan por el Mediterrneo a lo largo de un ao mediante el sistema AIS, realizando fotos del trfico martimo en el Mediterrneo y reportando todos los buques en navegacin en das aleatorios a lo largo de todo el ao 2014. Por ltimo, y con los datos anteriores, calculamos la demanda potencial de gasleo en el Mediterrneo. Si no se hace nada y los buques comienzan a consumir gasleo como combustible principal, en vez del actual fuel oil para cumplir con la regulacin, la demanda de gasoil en el Mediterrneo aumentar en 12,12 MTA (Millones de Toneladas Anuales) a partir del ao 2020. Esto supone alrededor de 3.720 millones de dlares anuales por el incremento del gasto de combustible tomando como referencia el precio medio de los combustibles marinos durante el ao 2014. El anterior incremento de demanda en el Mediterrneo supondra el 43% del total de la demanda de gasleos en Espaa en el ao 2013, incluyendo gasleos de automocin, biodiesel y gasleos marinos y el 3,2% del consumo europeo de destilados medios durante el ao 2014. Podr la oferta del mercado europeo asumir este incremento de demanda de gasleos? Europa siempre ha sido excedentaria en gasolina y deficitaria en destilados medios. En el ao 2009, Europa tuvo que importar 4,8 MTA de Norte Amrica y 22,1 MTA de Asia. Por lo que, este aumento de demanda sobre la ya limitada capacidad de refino de destilados medios en Europa incrementar las importaciones y producir tambin aumentos en los precios, sobre todo del mercado del gasleo. El sector sobre el que ms impactar el incremento de demanda de gasleo ser el de los cruceros que navegan por el Mediterrneo, pues consumirn un 30,4% de la demanda de combustible de toda flota mundial de cruceros, lo que supone un aumento en su gasto de combustible de 386 millones de USD anuales. En el caso de los RoRos, consumiran un 23,6% de la demanda de la flota mundial de este tipo de buque, con un aumento anual de 171 millones de USD sobre su gasto de combustible anterior. El mayor incremento de coste lo sufrirn los portacontenedores, con 1.168 millones de USD anuales sobre su gasto actual. Sin embargo, su consumo en el Mediterrneo representa slo el 5,3% del consumo mundial de combustible de este tipo de buques. Estos nmeros plantean la incertidumbre de si semejante aumento de gasto en buques RoRo har que el transporte martimo de corta distancia en general pierda competitividad sobre otros medios de transporte alternativos en determinadas rutas. De manera que, parte del volumen de mercancas que actualmente transportan los buques se podra trasladar a la carretera, con los inconvenientes medioambientales y operativos, que esto producira. En el caso particular de Espaa, el extra coste por el consumo de gasleo de todos los buques con escala en algn puerto espaol en el ao 2013 se cifra en 1.717 millones de EUR anuales, segn demostramos en la ltima parte del captulo 5. Para realizar este clculo hemos analizado con el sistema AIS a todos los buques que han tenido escala en algn puerto espaol y los hemos clasificado por distancia navegada, tipo de buque y potencia. Este encarecimiento del transporte martimo ser trasladado al sector exterior espaol, lo cual producir un aumento del coste de las importaciones y exportaciones por mar en un pas muy expuesto, pues el 75,61% del total de las importaciones y el 53,64% del total de las exportaciones se han hecho por va martima. Las tres industrias que se vern ms afectadas son aquellas cuyo valor de mercanca es inferior respecto a su coste de transporte. Para ellas los aumentos del coste sobre el total del valor de cada mercanca sern de un 2,94% para la madera y corcho, un 2,14% para los productos minerales y un 1,93% para las manufacturas de piedra, cemento, cermica y vidrio. Las mercancas que entren o salgan por los dos archipilagos espaoles de Canarias y Baleares sern las que se vern ms impactadas por el extra coste del transporte martimo, ya que son los puertos ms alejados de otros puertos principales y, por tanto, con ms distancia de navegacin. Sin embargo, esta no es la nica alternativa al cumplimiento de la nueva regulacin. De la lectura del captulo 6 concluimos que las tecnologas de equipos scrubbers y de propulsin con GNL permitirn al buque consumir combustibles ms baratos al gasoil, a cambio de una inversin en estas tecnologas. Sern los ahorros producidos por estas nuevas tecnologas suficientes para justificar su inversin? Para contestar la anterior pregunta, en el captulo 7 hemos comparado las tres alternativas y hemos calculado tanto los costes de inversin como los gastos operativos correspondientes a equipos scrubbers o propulsin con GNL para una seleccin de 53 categoras de buques. La inversin en equipos scrubbers es ms conveniente para buques grandes, con navegacin no regular. Sin embargo, para buques de tamao menor y navegacin regular por puertos con buena infraestructura de suministro de GNL, la inversin en una propulsin con GNL como combustible ser la ms adecuada. En el caso de un tiempo de navegacin del 100% dentro de zonas ECA y bajo el escenario de precios visto durante el ao 2014, los proyectos con mejor plazo de recuperacin de la inversin en equipos scrubbers son para los cruceros de gran tamao (100.000 tons. GT), para los que se recupera la inversin en 0,62 aos, los grandes portacontenedores de ms de 8.000 TEUs con 0,64 aos de recuperacin y entre 5.000-8.000 TEUs con 0,71 aos de recuperacin y, por ltimo, los grandes petroleros de ms de 200.000 tons. de peso muerto donde tenemos un plazo de recuperacin de 0,82 aos. La inversin en scrubbers para buques pequeos, por el contrario, tarda ms tiempo en recuperarse llegando a ms de 5 aos en petroleros y quimiqueros de menos de 5.000 toneladas de peso muerto. En el caso de una posible inversin en propulsin con GNL, las categoras de buques donde la inversin en GNL es ms favorable y recuperable en menor tiempo son las ms pequeas, como ferris, cruceros o RoRos. Tomamos ahora el caso particular de un buque de productos limpios de 38.500 toneladas de peso muerto ya construido y nos planteamos la viabilidad de la inversin en la instalacin de un equipo scrubber o bien, el cambio a una propulsin por GNL a partir del ao 2015. Se comprueba que las dos variables que ms impactan sobre la conveniencia de la inversin son el tiempo de navegacin del buque dentro de zonas de emisiones controladas (ECA) y el escenario futuro de precios del MGO, HSFO y GNL. Para realizar este anlisis hemos estudiado cada inversin, calculando una batera de condiciones de mrito como el payback, TIR, VAN y la evolucin de la tesorera del inversor. Posteriormente, hemos calculado las condiciones de contorno mnimas de este buque en concreto para asegurar una inversin no slo aceptable, sino adems conveniente para el naviero inversor. En el entorno de precios del 2014 -con un diferencial entre fuel y gasleo de 264,35 USD/ton- si el buque pasa ms de un 56% de su tiempo de navegacin en zonas ECA, conseguir una rentabilidad de la inversin para inversores (TIR) en el equipo scrubber que ser igual o superior al 9,6%, valor tomado como coste de oportunidad. Para el caso de inversin en GNL, en el entorno de precios del ao 2014 -con un diferencial entre GNL y gasleo de 353,8 USD/ton FOE- si el buque pasa ms de un 64,8 % de su tiempo de navegacin en zonas ECA, conseguir una rentabilidad de la inversin para inversores (TIR) que ser igual o superior al 9,6%, valor del coste de oportunidad. Para un tiempo en zona ECA estimado de un 60%, la rentabilidad de la inversin (TIR) en scrubbers para los inversores ser igual o superior al 9,6%, el coste de oportunidad requerido por el inversor, para valores del diferencial de precio entre los dos combustibles alternativos, gasleo (MGO) y fuel oil (HSFO) a partir de 244,73 USD/ton. En el caso de una inversin en propulsin GNL se requerira un diferencial de precio entre MGO y GNL de 382,3 USD/ton FOE o superior. As, para un buque de productos limpios de 38.500 DWT, la inversin en una reconversin para instalar un equipo scrubber es ms conveniente que la de GNL, pues alcanza rentabilidades de la inversin (TIR) para inversores del 12,77%, frente a un 6,81% en el caso de invertir en GNL. Para ambos clculos se ha tomado un buque que navegue un 60% de su tiempo por zona ECA y un escenario de precios medios del ao 2014 para el combustible. Po otro lado, las inversiones en estas tecnologas a partir del ao 2025 para nuevas construcciones son en ambos casos convenientes. El naviero deber prestar especial atencin aqu a las caractersticas propias de su buque y tipo de navegacin, as como a la infraestructura de suministros y vertidos en los puertos donde vaya a operar usualmente. Si bien, no se ha estudiado en profundidad en esta tesis, no olvidemos que el sector martimo debe cumplir adems con las otras dos limitaciones que la regulacin de la OMI establece sobre las emisiones de xidos de Nitrgeno (NOx) y Carbono (CO2) y que sin duda, requerirn adicionales inversiones en diversos equipos. De manera que, si bien las consecuencias del consumo de gasleo como alternativa al cumplimiento de la Regulacin MARPOL son ciertamente preocupantes, existen alternativas al uso del gasleo, con un aumento sobre el coste del transporte martimo menor y manteniendo los beneficios sociales que pretende dicha ley. En efecto, como hemos demostrado, las opciones que se plantean como ms rentables desde el punto de vista financiero son el consumo de GNL en los buques pequeos y de lnea regular (cruceros, ferries, RoRos), y la instalacin de scrubbers para el resto de buques de grandes dimensiones. Pero, por desgracia, estas inversiones no llegan a hacerse realidad por el elevado grado de incertidumbre asociado a estos dos mercados, que aumenta el riesgo empresarial, tanto de navieros como de suministradores de estas nuevas tecnologas. Observamos as una gran reticencia del sector privado a decidirse por estas dos alternativas. Este elevado nivel de riesgo slo puede reducirse fomentando el esfuerzo conjunto del sector pblico y privado para superar estas barreras de entrada del mercado de scrubbers y GNL, que lograran reducir las externalidades medioambientales de las emisiones sin restar competitividad al transporte martimo. Creemos as, que los mismos organismos que aprobaron dicha ley deben ayudar al sector naviero a afrontar las inversiones en dichas tecnologas, as como a impulsar su investigacin y promover la creacin de una infraestructura portuaria adaptada a suministros de GNL y a descargas de vertidos procedentes de los equipos scrubber. Deberan adems, prestar especial atencin sobre las ayudas al sector de corta distancia para evitar que pierda competitividad frente a otros medios de transporte por el cumplimiento de esta normativa. Actualmente existen varios programas europeos de incentivos, como TEN-T o Marco Polo, pero no los consideramos suficientes. Por otro lado, la Organizacin Martima Internacional debe confirmar cuanto antes si retrasa o no al 2025 la nueva bajada del nivel de azufre en combustibles. De esta manera, se eliminara la gran incertidumbre temporal que actualmente tienen tanto navieros, como empresas petroleras y puertos para iniciar sus futuras inversiones y poder estudiar la viabilidad de cada alternativa de forma individual. ABSTRACT On 10 October 2008 the International Maritime Organization (IMO) signed an amendment to Annex VI of the MARPOL 73/78 convention establishing a gradual reduction in sulphur oxide (SOx) emissions from ships, and an additional reduction in nitrogen oxide (NOx) emissions and carbon dioxide (CO2) emissions from marine engines which cause environmental problems such as acid rain and the greenhouse effect. According to this regulation, from 1 January 2015, ships travelling in an Emission Control Area (ECA) must use fuels with a sulphur content of less than 0.1%. From 1 January 2020, or alternatively from 2025 if the IMO should decide to delay its introduction, all ships must use fuels with a sulphur content of less than 0.5%. As before, this content will be 0.1%S for voyages within ECAs. Meanwhile, the European Union has gone further than the IMO, and will apply the strictest limits of the MARPOL directives in the waters of its exclusive economic zone from 2020. To this end, Directive 2012/33/EU was issued on 21 November 2013 as an addendum to the 1999 Directive. These laws are intended to improve public health and the environment, benefiting society by reducing disease, particularly respiratory problems. The first question which arises is: what fuel do ships currently use, and what fuel will they have to use to comply with the Convention? Today, large international shipping vessels consume fuel oil with a sulphur level of 3.5%. Do fuel oils exist with a sulphur level of 0.5%S? As we conclude in Chapter 4, oil companies regard marine fuel oil as a by-product of refining Brent to produce their basket of products, as the demand for fuel oil is declining in comparison to other products, and the profit margin on the sale of other petroleum products is higher. Thus, oil companies are not interested in investing in their refineries to produce low-sulphur fuel oils, and if a company should decide to invest in producing a 0.5%S fuel oil, its price would have to be very similar to that of marine gas oil in order to recoup the investment. Therefore, the only fuel which presently complies with the new levels required by the IMO is marine gas oil, which was priced on average 307 USD/tonne higher than current fuel oils during 2014. This higher purchasing price for fuel will have a direct impact on the cost of maritime transport. The entry into force of the above directive presents a challenge for the entire maritime sector. There are various alternative approaches to this situation, with different technical, operational and financial implications. At present three options are the most widespread in the sector. The first option consists of doing nothing and simply switching from fuel oil to marine gas oil in large ships. The second option is installing a scrubber system, which would enable ships to continue consuming fuel oil, cleaning the combustion gases before they are released to the atmosphere. And finally, the third option is using Liquefied Natural Gas (LNG), which is priced lower than marine gas oil, as a fuel. However, there is still significant uncertainty on future variations in prices, the operation and maintenance of the new technologies, the investments required, the availability of port infrastructure and even future developments in the international regulations themselves. These uncertainties mean that none of these three alternatives has been unanimously accepted by the sector. In this Thesis, after discussing all the regulations applicable to the sector in Chapter 3, we investigate their consequences. In Chapter 4 we examine whether there are currently any marine fuels on the market which meet the new sulphur limits, and if not, how much new fuels would cost. In Chapter 5, based on the hypothesis that all ships will switch from fuel oil to marine gas oil to comply with the regulations, we calculate the increase in demand for marine gas oil this would lead to, and analyse the consequences this would have on marine gas oil production in the Mediterranean. We also calculate the economic impact such a cost increase would have on Spain's external sector. To do this, we also use the Automatic Identification System (AIS) system to analyse the data of every ship stopping in any Spanish port, in order to calculate the extra cost of using marine gas oil in maritime transport for all Spain's imports and exports. Finally, in Chapter 6, we examine and compare the other two alternatives to marine gas oil, scrubbers and LNG, and in Chapter 7 we analyse the viability of investing in these two technologies in order to comply with the regulations. In Chapter 5 we explain the many existing methods for calculating a ship's fuel consumption. We use a bottom-up calculation method, based on aggregating the activity and characteristics of each type of vessel. The result is based on the installed engine power of each ship, the engine load percentage and its specific consumption. To do this, we analyse the number of ships travelling in the Mediterranean in the course of one year, using the AIS, a marine traffic monitoring system, to take snapshots of marine traffic in the Mediterranean and report all ships at sea on random days throughout 2014. Finally, with the above data, we calculate the potential demand for marine gas oil in the Mediterranean. If nothing else is done and ships begin to use marine gas oil instead of fuel oil in order to comply with the regulation, the demand for marine gas oil in the Mediterranean will increase by 12.12 MTA (Millions Tonnes per Annum) from 2020. This means an increase of around 3.72 billion dollars a year in fuel costs, taking as reference the average price of marine fuels in 2014. Such an increase in demand in the Mediterranean would be equivalent to 43% of the total demand for diesel in Spain in 2013, including automotive diesel fuels, biodiesel and marine gas oils, and 3.2% of European consumption of middle distillates in 2014. Would the European market be able to supply enough to meet this greater demand for diesel? Europe has always had a surplus of gasoline and a deficit of middle distillates. In 2009, Europe had to import 4.8 MTA from North America and 22.1 MTA from Asia. Therefore, this increased demand on Europe's already limited capacity for refining middle distillates would lead to increased imports and higher prices, especially in the diesel market. The sector which would suffer the greatest impact of increased demand for marine gas oil would be Mediterranean cruise ships, which represent 30.4% of the fuel demand of the entire world cruise fleet, meaning their fuel costs would rise by 386 million USD per year. ROROs in the Mediterranean, which represent 23.6% of the demand of the world fleet of this type of ship, would see their fuel costs increase by 171 million USD a year. The greatest cost increase would be among container ships, with an increase on current costs of 1.168 billion USD per year. However, their consumption in the Mediterranean represents only 5.3% of worldwide fuel consumption by container ships. These figures raise the question of whether a cost increase of this size for RORO ships would lead to short-distance marine transport in general becoming less competitive compared to other transport options on certain routes. For example, some of the goods that ships now carry could switch to road transport, with the undesirable effects on the environment and on operations that this would produce. In the particular case of Spain, the extra cost of switching to marine gas oil in all ships stopping at any Spanish port in 2013 would be 1.717 billion EUR per year, as we demonstrate in the last part of Chapter 5. For this calculation, we used the AIS system to analyse all ships which stopped at any Spanish port, classifying them by distance travelled, type of ship and engine power. This rising cost of marine transport would be passed on to the Spanish external sector, increasing the cost of imports and exports by sea in a country which relies heavily on maritime transport, which accounts for 75.61% of Spain's total imports and 53.64% of its total exports. The three industries which would be worst affected are those with goods of lower value relative to transport costs. The increased costs over the total value of each good would be 2.94% for wood and cork, 2.14% for mineral products and 1.93% for manufactured stone, cement, ceramic and glass products. Goods entering via the two Spanish archipelagos, the Canary Islands and the Balearic Islands, would suffer the greatest impact from the extra cost of marine transport, as these ports are further away from other major ports and thus the distance travelled is greater. However, this is not the only option for compliance with the new regulations. From our readings in Chapter 6 we conclude that scrubbers and LNG propulsion would enable ships to use cheaper fuels than marine gas oil, in exchange for investing in these technologies. Would the savings gained by these new technologies be enough to justify the investment? To answer this question, in Chapter 7 we compare the three alternatives and calculate both the cost of investment and the operating costs associated with scrubbers or LNG propulsion for a selection of 53 categories of ships. Investing in scrubbers is more advisable for large ships with no fixed runs. However, for smaller ships with regular runs to ports with good LNG supply infrastructure, investing in LNG propulsion would be the best choice. In the case of total transit time within an ECA and the pricing scenario seen in 2014, the best payback periods on investments in scrubbers are for large cruise ships (100,000 gross tonnage), which would recoup their investment in 0.62 years; large container ships, with a 0.64 year payback period for those over 8,000 TEUs and 0.71 years for the 5,000-8,000 TEU category; and finally, large oil tankers over 200,000 deadweight tonnage, which would recoup their investment in 0.82 years. However, investing in scrubbers would have a longer payback period for smaller ships, up to 5 years or more for oil tankers and chemical tankers under 5,000 deadweight tonnage. In the case of LNG propulsion, a possible investment is more favourable and the payback period is shorter for smaller ship classes, such as ferries, cruise ships and ROROs. We now take the case of a ship transporting clean products, already built, with a deadweight tonnage of 38,500, and consider the viability of investing in installing a scrubber or changing to LNG propulsion, starting in 2015. The two variables with the greatest impact on the advisability of the investment are how long the ship is at sea within emission control areas (ECA) and the future price scenario of MGO, HSFO and LNG. For this analysis, we studied each investment, calculating a battery of merit conditions such as the payback period, IRR, NPV and variations in the investors' liquid assets. We then calculated the minimum boundary conditions to ensure the investment was not only acceptable but advisable for the investor shipowner. Thus, for the average price differential of 264.35 USD/tonne between HSFO and MGO during 2014, investors' return on investment (IRR) in scrubbers would be the same as the required opportunity cost of 9.6%, for values of over 56% ship transit time in ECAs. For the case of investing in LNG and the average price differential between MGO and LNG of 353.8 USD/tonne FOE in 2014, the ship must spend 64.8% of its time in ECAs for the investment to be advisable. For an estimated 60% of time in an ECA, the internal rate of return (IRR) for investors equals the required opportunity cost of 9.6%, based on a price difference of 244.73 USD/tonne between the two alternative fuels, marine gas oil (MGO) and fuel oil (HSFO). An investment in LNG propulsion would require a price differential between MGO and LNG of 382.3 USD/tonne FOE. Thus, for a 38,500 DWT ship carrying clean products, investing in retrofitting to install a scrubber is more advisable than converting to LNG, with an internal rate of return (IRR) for investors of 12.77%, compared to 6.81% for investing in LNG. Both calculations were based on a ship which spends 60% of its time at sea in an ECA and a scenario of average 2014 prices. However, for newly-built ships, investments in either of these technologies from 2025 would be advisable. Here, the shipowner must pay particular attention to the specific characteristics of their ship, the type of operation, and the infrastructure for supplying fuel and handling discharges in the ports where it will usually operate. Thus, while the consequences of switching to marine gas oil in order to comply with the MARPOL regulations are certainly alarming, there are alternatives to marine gas oil, with smaller increases in the costs of maritime transport, while maintaining the benefits to society this law is intended to provide. Indeed, as we have demonstrated, the options which appear most favourable from a financial viewpoint are conversion to LNG for small ships and regular runs (cruise ships, ferries, ROROs), and installing scrubbers for large ships. Unfortunately, however, these investments are not being made, due to the high uncertainty associated with these two markets, which increases business risk, both for shipowners and for the providers of these new technologies. This means we are seeing considerable reluctance regarding these two options among the private sector. This high level of risk can be lowered only by encouraging joint efforts by the public and private sectors to overcome these barriers to entry into the market for scrubbers and LNG, which could reduce the environmental externalities of emissions without affecting the competitiveness of marine transport. Our opinion is that the same bodies which approved this law must help the shipping industry invest in these technologies, drive research on them, and promote the creation of a port infrastructure which is adapted to supply LNG and handle the discharges from scrubber systems. At present there are several European incentive programmes, such as TEN-T and Marco Polo, but we do not consider these to be sufficient. For its part, the International Maritime Organization should confirm as soon as possible whether the new lower sulphur levels in fuels will be postponed until 2025. This would eliminate the great uncertainty among shipowners, oil companies and ports regarding the timeline for beginning their future investments and for studying their viability.
Resumo:
In the EU context extraction of shale and oil gas by hydraulic fracturing (fracking) differs from country to country in terms of legislation and implementation. While fossil fuel extraction using this technology is currently taking place in the UK, Germany and France have adopted respective moratoria. In between is the Spanish case, where hydrocarbon extraction projects through fracking have to undergo mandatory and routine environmental assessment in accordance with the last changes to environmental regulations. Nowadays Spain is at the crossroad with respect to the future of this technology. We presume a social conflictt in our country since the position and strategy of the involved and confronted social actors -national, regional and local authorities, energy companies, scientists, NGO and other social organization- are going to play key and likely divergent roles in its industrial implementation and public acceptance. In order to improve knowledge on how to address these controverted situations from the own engineering context, the affiliated units from the Higher Technical School of Mines and Energy Engineering at UPM have been working on a transversal program to teach values and ethics. Over the past seven years, this pioneering experience has shown the usefulness of applying a consequentialist ethics, based on a case-by-case approach and costs-benefits analysis both for action and inaction. As a result of this initiative a theoretical concept has arisen and crystallized in this field: it is named Inter-ethics. This theoretical perspective can be very helpful in complex situations, with multi-stakeholders and plurality of interests, when ethical management requires the interaction between the respective ethics of each group; professional ethics of a single group is not enough. Under this inter-ethics theoretical framework and applying content analysis techniques, this paper explores the articulation of the discourse in favour and against fracking technology and its underlying values as manifested in the Spanish traditional mass media and emerging social media such as Youtube. Results show that Spanish public discourse on fracking technology includes the costs-benefits analysis to communicate how natural resources from local communities may be affected by these facilities due to environmental, health and economic consequences. Furthermore, this technology is represented as a solution to the "demand of energy" according to the optimistic discourse while, from a pessimistic view, fracking is often framed as a source "environmental problems" and even natural disasters as possible earthquakes. In this latter case, this negative representation could have been influenced by the closure of a macro project to store injected natural gas in the Mediterranean Sea using the old facilities of an oil exploitation in Amposta (Proyecto Cstor). The closure of this project was due to the occurrence of earthquakes whose intensity was higher than the originally expected by the experts in the assessment stage of the project.
Resumo:
Processos como a purificao do metano (CH4) e a produo de hidrognio gasoso (H2) envolvem etapas de separao de CO2. Atualmente, etanolaminas como monoetanolamina (MEA), dietanolamina (DEA), metildietanolamina (MDEA) e trietanolamina (TEA) so as substncias mais utilizadas no processo de separao/captura de CO2 em processos industriais. Entretanto, o uso destas substncias apresenta alguns inconvenientes devido alta volatilidade, dificuldade de se trabalhar com material lquido, tambm ao alto gasto energtico envolvido das etapas de regenerao e baixa estabilidade trmica e qumica. Com base nessa problemtica, esse trabalho teve por objetivo a sntese de um tipo de slica mesoporosa altamente ordenada (SBA-15) de modo a utiliz-la no processo de captura de CO2. O trabalho foi dividido em quatro etapas experimentais que envolveram a sntese da SBA-15, o estudo do comportamento trmico de algumas etanolaminas livres, sntese e caracterizao de materiais adsorventes preparados a partir de incorporao de etanolaminas SBA-15 e estudo da eficincia de captura de CO2 por esses materiais. Novas alternativas de sntese da SBA-15 foram estudadas neste trabalho, visando aperfeioar as propriedades texturais do material produzido. Tais alternativas so baseadas na remoo do surfatante, utilizado como molde na sntese da slica mesoporosa, por meio da extrao por Soxhlet, utilizando diferentes solventes. O processo contribuiu para melhorar as propriedades do material obtido, evitando o encolhimento da estrutura que pode ser ocasionado durante a etapa de calcinao. Por meio de tcnicas como TG/DTG, DSC, FTIR e Anlise Elementar de C, H e N foi realizada a caracterizao fsico-qumica e termoanaltica da MEA, DEA, MDEA e TEA, visando melhor conhecer as caractersticas destas substncias. Estudos cinticos baseados nos mtodos termogravimtricos isotrmicos e no isotrmicos (Mtodo de Ozawa) foram realizados, permitindo a determinao de parmetros cinticos envolvidos nas etapas de volatilizao/decomposio trmica das etanolaminas. Alm das tcnicas acima mencionadas, MEV, MET, SAXS e Medidas de Adsoro de N2 foram utilizadas na caraterizao da SBA-15 antes e aps a incorporao das etanolaminas. Dentre as etanolaminas estudadas, a TEA apresentou maior estabilidade trmica, entretanto, devido ao seu maior impedimento estrico, a etanolamina que apresenta menor afinidade com o CO2. Diferentemente das demais etanolaminas estudadas, a decomposio trmica da DEA envolve uma reao intramolecular, levando a formao de MEA e xido de etileno. A incorporao destes materiais SBA-15 aumentou a estabilidade trmica das etanolaminas, uma vez que parte do material permanece dentro dos poros da slica. Os ensaios de adsoro de CO2 mostraram que a incorporao da MEA SBA-15 catalisou o processo de decomposio trmica da mesma. A MDEA foi a etanolamina que apresentou maior poder de captura de CO2 e sua estabilidade trmica foi consideravelmente aumentada quando a mesma foi incorporada SBA-15, aumentando tambm seu potencial de captura de CO2.
Resumo:
A demanda crescente por energia tem motivado a procura por petrleo e gs natural em ambientes com condies extremas, como operaes em guas profundas e o transporte de fludos corrosivos. Avanos tecnolgicos recentes favorecem o uso de tubos de ao contendo uma camada interna resistente a corroso (comumente chamados de Lined ou Clad Pipes) para o transporte de tais fluidos agressivos. Alm disso, as tubulaes submarinas so sujeitas a condies de instalao muito severas e, um caso de interesse, o procedimento de reeling que permite com que a fabricao e inspeo da tubulao seja feita em terra. Apesar de possuir vantagens econmicas, a avaliao da integridade estrutural e especificao dos tamanhos tolerveis de trinca em juntas soldadas, nestas condies, torna-se uma tarefa complexa, devido a natureza dissimilar dos materiais e ao grande nvel de deformao plstica no processo. Dessa maneira, este trabalho tem por objetivo o desenvolvimento de um procedimento de avaliao de foras motrizes elasto-plsticas em tubos contendo juntas soldadas circunferenciais sujeitos a flexo, para uma extensa gama de configuraes geomtricas. Dois mtodos distintos foram desenvolvidos e analisados: a metodologia EPRI e o procedimento que utiliza a curva de tenso vs. deformao equivalente. As anlises numricas 3D fornecem os parmetros de fratura necessrios para a resoluo do problema e a acurcia dos procedimentos verificada a partir de estudos de casos e anlises paramtricas.
Resumo:
O trabalho aborda a aplicao da tcnica de reconciliao de dados para o balano da movimentao de gs natural em uma malha de escoamento de gs no processado, elaborando tambm um mtodo de clculo rpido de inventrio de um duto. Foram aplicadas, separadamente, a reconciliao volumtrica condio padro de medio e a reconciliao mssica, bem como realizadas comparaes dos resultados em relao ao balano original e verificao do balano resultante de energia em termos de poder calorfico superior. Dois conjuntos de pesos foram aplicados, um arbitrado de acordo com o conhecimento prvio da qualidade do sistema de medio de cada um dos pontos, outro baseado no inverso da varincia dos volumes dirios apurados no perodo. Ambos apresentaram bons resultados e o segundo foi considerado o mais apropriado. Por meio de uma abordagem termodinmica, foi avaliado o potencial impacto, ao balano, da condensao de parte da fase gs ao longo do escoamento e a injeo de um condensado de gs natural no estabilizado por uma das fontes. Ambos tendem a impactar o balano, sendo o resultado esperado um menor volume, massa e energia de fase gs na sada. Outros fatores de considervel impacto na qualidade dos dados e no resultado final da reconciliao so a qualidade da medio de sada do sistema e a representatividade da composio do gs neste ponto. O inventrio calculado a partir de uma regresso que se baseia em um regime permanente de escoamento, o que pode apresentar maior desvio quando fortes transientes esto ocorrendo no ltimo dia do ms, porm a variao de inventrio ao longo do ms possui baixo impacto no balano. Concluiu-se que a reconciliao volumtrica a mais apropriada para este sistema, pois os dados reconciliados levam os balanos mssicos e de energia em termos de poder calorfico, ambos na fase gs, para dentro do perfil esperado de comportamento. Embora um balano volumtrico nulo apenas da fase gs no seja por si s o comportamento esperado quando se considera os efeitos descritos, para desenvolver um balano mais robusto necessrio considerar as fraes lquidas presentes no sistema, agregando maior dificuldade na aquisio e qualidade dos dados.
Resumo:
As recentes descobertas de petrleo e gs na camada do Pr-sal representam um enorme potencial exploratrio no Brasil, entretanto, os desafios tecnolgicos para a explorao desses recursos minerais so imensos e, consequentemente, tm motivado o desenvolvimento de estudos voltados a mtodos e materiais eficientes para suas produes. Os tubos condutores de petrleo e gs so denominados de elevadores catenrios ou do ingls \"risers\", e so elementos que necessariamente so soldados e possuem fundamental importncia nessa cadeia produtiva, pois transportam petrleo e gs natural do fundo do mar plataforma, estando sujeitos a carregamentos dinmicos (fadiga) durante sua operao. Adicionalmente, um dos problemas centrais produo de leo e gs das reservas do Pr-Sal est diretamente associado a meios altamente corrosivos, tais como H2S e CO2. Uma forma mais barata de proteo dos tubos a aplicao de uma camada de um material metlico resistente corroso na parte interna desses tubos (clad). Assim, a unio entre esses tubos para formao dos \"risers\" deve ser realizada pelo emprego de soldas circunferenciais de ligas igualmente resistentes corroso. Nesse contexto, como os elementos soldados so considerados possuir defeitos do tipo trinca, para a garantia de sua integridade estrutural quando submetidos a carregamentos cclicos, necessrio o conhecimento das taxas de propagao de trinca por fadiga da solda circunferencial. Assim, neste trabalho, foram realizados ensaios de propagao de trinca por fadiga na regio da solda circunferencial de Inconel 625 realizada em tubo de ao API 5L X65 cladeado, utilizando corpos de prova do tipo SEN(B) (Single Edge Notch Bending) com relaes entre espessura e largura (B/W) iguais a 0,5, 1 e 2. O propsito central deste trabalho foi de obter a curva da taxa de propagao de trinca por fadiga (da/dN) versus a variao do fator de intensidade de tenso (ΔK) para o metal de solda por meio de ensaios normatizados, utilizando diferentes tcnicas de acompanhamento e medio da trinca. A monitorao de crescimento da trinca foi feita por trs tcnicas: variao da flexibilidade elstica (VFE), queda de potencial eltrico (QPE) e anlise de imagem (Ai). Os resultados mostraram que as diferentes relaes B/W utilizadas no estudo no alteraram significantemente as taxas de propagao de trinca por fadiga, respeitado que a propagao aconteceu em condies de escoamento em pequena escala na frente da trinca. Os resultados de propagao de trinca por fadiga permitiram a obteno das regies I e II da curva da/dN versus ΔK para o metal de solda. O valor de ΔKlim obtido para o mesmo foi em torno de 11,8 MPa.m1/2 e os valores encontrados das constantes experimentais C e m da equao de Paris-Erdogan foram respectivamente iguais a 1,55 x10-10 [(mm/ciclo)/(MPa.m1/2)m] e 4,15. A propagao de trinca no metal de solda deu-se por deformao plstica, com a formao de estrias de fadiga.
