Influence of the composition of natural gas-hydrogen blends (HCNG) on performance an CO2 emissions of a spark ignition engine

Addition of hydrogen to natural gas could be a short-term alternative to nowadays fossil fuels as the emissions of greenhouse gases may be reduced. The aim of this study is to evaluate the performance and emissions of a park ignition engine fuelled with pure natural gas, pure hydrogen and different blends of hydrogen and natural gas (HCNG). The increase of the hydrogen fraction leads to variations in the cylinder pressure and CO2 emissions. In this work, a combustion model based on thermodynamic equations is used considering separated zones for the burned and unburned gases. The results show that the maximum cylinder pressure gets higher as the fraction of hydrogen in the blend increases. The presence of hydrogen in the blend leads to a drecrease in the CO2 emissions. Due to hydrogen properties, leaner fuel-air mixtures can be used along with the appropiate spark timing, leading to an engine emissions improvement without a performance worsening.

Life cycle assessment of concentrated solar power (CSP) and the influence of hybridising with natural gas

Purpose Concentrating Solar Power (CSP) plants based on parabolic troughs utilize auxiliary fuels (usually natural gas) to facilitate start-up operations, avoid freezing of HTF and increase power output. This practice has a significant effect on the environmental performance of the technology. The aim of this paper is to quantify the sustainability of CSP and to analyse how this is affected by hybridisation with different natural gas (NG) inputs. Methods A complete Life Cycle (LC) inventory was gathered for a commercial wet-cooled 50 MWe CSP plant based on parabolic troughs. A sensitivity analysis was conducted to evaluate the environmental performance of the plant operating with different NG inputs (between 0 and 35% of gross electricity generation). ReCiPe Europe (H) was used as LCA methodology. CML 2 baseline 2000 World and ReCiPe Europe E were used for comparative purposes. Cumulative Energy Demands (CED) and Energy Payback Times (EPT) were also determined for each scenario. Results and discussion Operation of CSP using solar energy only produced the following environmental profile: climate change 26.6 kg CO2 eq/KWh, human toxicity 13.1 kg 1,4-DB eq/KWh, marine ecotoxicity 276 g 1,4-DB eq/KWh, natural land transformation 0.005 m2/KWh, eutrophication 10.1 g P eq/KWh, acidification 166 g SO2 eq/KWh. Most of these impacts are associated with extraction of raw materials and manufacturing of plant components. The utilization NG transformed the environmental profile of the technology, placing increasing weight on impacts related to its operation and maintenance. Significantly higher impacts were observed on categories like climate change (311 kg CO2 eq/MWh when using 35 % NG), natural land transformation, terrestrial acidification and fossil depletion. Despite its fossil nature, the use of NG had a beneficial effect on other impact categories (human and marine toxicity, freshwater eutrophication and natural land transformation) due to the higher electricity output achieved. The overall environmental performance of CSP significantly deteriorated with the use of NG (single score 3.52 pt in solar only operation compared to 36.1 pt when using 35 % NG). Other sustainability parameters like EPT and CED also increased substantially as a result of higher NG inputs. Quasilinear second-degree polynomial relationships were calculated between various environmental performance parameters and NG contributions. Conclusions Energy input from auxiliary NG determines the environmental profile of the CSP plant. Aggregated analysis shows a deleterious effect on the overall environmental performance of the technology as a result of NG utilization. This is due primarily to higher impacts on environmental categories like climate change, natural land transformation, fossil fuel depletion and terrestrial acidification. NG may be used in a more sustainable and cost-effective manner in combined cycle power plants, which achieve higher energy conversion efficiencies.

Hybridizing concentrated solar power (CSP) with biogas and biomethane as an alternative to natural gas: Analysis of environmental performance using LCA

Concentrating Solar Power (CSP) plants typically incorporate one or various auxiliary boilers operating in parallel to the solar field to facilitate start up operations, provide system stability, avoid freezing of heat transfer fluid (HTF) and increase generation capacity. The environmental performance of these plants is highly influenced by the energy input and the type of auxiliary fuel, which in most cases is natural gas (NG). Replacing the NG with biogas or biomethane (BM) in commercial CSP installations is being considered as a means to produce electricity that is fully renewable and free from fossil inputs. Despite their renewable nature, the use of these biofuels also generates environmental impacts that need to be adequately identified and quantified. This paper investigates the environmental performance of a commercial wet-cooled parabolic trough 50 MWe CSP plant in Spain operating according to two strategies: solar-only, with minimum technically viable energy non-solar contribution; and hybrid operation, where 12 % of the electricity derives from auxiliary fuels (as permitted by Spanish legislation). The analysis was based on standard Life Cycle Assessment (LCA) methodology (ISO 14040-14040). The technical viability and the environmental profile of operating the CSP plant with different auxiliary fuels was evaluated, including: NG; biogas from an adjacent plant; and BM withdrawn from the gas network. The effect of using different substrates (biowaste, sewage sludge, grass and a mix of biowaste with animal manure) for the production of the biofuels was also investigated. The results showed that NG is responsible for most of the environmental damage associated with the operation of the plant in hybrid mode. Replacing NG with biogas resulted in a significant improvement of the environmental performance of the installation, primarily due to reduced impact in the following categories: natural land transformation, depletion of fossil resources, and climate change. However, despite the renewable nature of the biofuels, other environmental categories like human toxicity, eutrophication, acidification and marine ecotoxicity scored higher when using biogas and BM.

Clasificaci��n de zonas en instalaciones para veh��culos propulsados por GNC

El presente proyecto tiene como objetivo principal el an��lisis de la viabilidad de estacionamiento de veh��culos propulsados por gas natural comprimido (GNC) desde el punto de vista de formaci��n de atmosferas potencialmente explosivas en los garajes subterr��neos. Adem��s se ha realizado una breve introducci��n sobre el GNC explicando el origen, la composici��n y los diferentes usos que tiene. Se ha realizado la evaluaci��n de riesgos asociados a la utilizaci��n de veh��culos propulsados por gas natural y estimaci��n de tasas de escape en el circuito de combustible de los veh��culos propulsados por GNC. Para ello se ha aplicado la normativa UNE EN 60079-10 traspuesta en Espa��a mediante el Real Decreto del 681/2003 sobre la salud y la seguridad de los trabajadores y el Real Decreto 400/1996 sobre aparatos y sistemas de protecci��n para su uso en atm��sferas explosivas. Finalmente se han expuesto las medidas de prevenci��n y protecci��n necesarias para prevenir la generaci��n de atmosferas potencialmente explosivas en los garajes subterr��neos y se han detallado los procedimientos y las operaciones que han de realizarse. En las conclusiones se han explicado las acciones m��s importantes que deben emprenderse para mejorar la seguridad de personas e instalaciones en las ��reas de riesgo por presencia de atm��sferas potencialmente explosivas. ABSTRACT The main objective of this project is to analyze the viability of the parking of vehicles powered by compressed natural gas (CNG) in the underground garages from the point of view of generated of potentially explosive atmospheres in garages. A brief introduction about the CNG explaining the origin, composition and the different uses that it has is also included. An assessment of the risks associated with the use of vehicles powered by natural gas has been provided as well as an estimate of the exhaust rates on the gas circuit of CNG vehicles. In order to do that, the standard UNE EN 60079-10 transposed in Spain by the Royal Decree 681/2003 about the health and safety of workers and the Royal Decree 400/1996 about equipment and protection systems to be used in explosive atmospheres have been applied. Finally, the necessary preventive and protective measures to prevent the generation of potentially explosive atmospheres in underground garages have been presented and the procedures and operations to be performed have been detailed. In the conclusions, the most important actions to be taken in order to improve the safety of people and facilities in the areas at risk of having potentially explosive atmospheres have been described.

Mejora de la movilidad urbana sostenible en el municipio de Madrid : aplicaci��n del an��lisis geoespacial en la ampliaci��n de la red de suministro de combustibles alternativos.

Este Trabajo Fin de Grado trata de dar respuesta a un problema de movilidad sostenible en el municipio de Madrid. Mediante las herramientas de an��lisis geoespacial de los Sistemas de Informaci��n Geogr��fica (SIG) se buscan soluciones para la ampliaci��n de la red de estaciones de suministro de combustibles alternativos como el Gas Licuado de Petr��leo (GLP), Gas Natural Comprimido (GNC) y electricidad. Los resultados obtenidos determinan las posibles ubicaciones de los nuevos puntos atendiendo a criterios espec��ficos seg��n el tipo de combustible. Estas soluciones procuran que se alcancen las medidas impuestas por las directivas europeas en la materia de las Smart Cities. Adem��s, con este Trabajo se muestran las capacidades de gesti��n de los SIG en el ��mbito urbano y sus posibles aplicaciones. ABSTRACT: This Final Project answers the problem of sustainable mobility in the city of Madrid. By means of geospatial analysis tools of Geographic Information Systems (GIS) solutions are searched to extend the supply stations network for alternative fuels like Liquefied Petroleum Gas (LPG), Compressed Natural Gas (CNG) and electricity. The final results are the best possible locations of new items according to specific criteria depending on the type of fuel. These solutions seek to the measures imposed by the European directives are reached in the field of Smart Cities. In addition, This Final Project shows management capabilities of GIS in urban areas and their possible application.

Dimensionamiento del proceso de licuaci��n de una planta de gas natural Offshore

Este proyecto consiste en el dimensionamiento del proceso de licuaci��n de una planta offshore para la producci��n de gas natural licuado, usando ��nicamente N2 como refrigerante, evitando de este modo riesgos potenciales que podr��an surgir con el uso de refrigerantes mixtos compuestos de hidrocarburos. El proceso ha sido dise��ado para acomodar 35,23 kg/s (aproximadamente un mill��n de toneladas por a��o) de gas natural seco, sin separaci��n de gases licuados de petr��leo (GLP) y ajustarlo dentro de los par��metros requeridos en las especificaciones del proceso. Para proceder al dimensionamiento del proceso de licuaci��n de gas natural de la planta se ha empleado el programa Aspen Plus. Los sistemas floating production, storage and offloading para licuar el gas natural (LNG-FPSO), es una nueva unidad conceptual y un modo realista y efectivo para la explotaci��n, recuperaci��n, almacenamiento, transporte y agotamiento de los campos marginales de gas y las fuentes de gas asociadas offshore. En el proyecto se detalla el proceso, equipos necesarios y costes estimados, potencia aproximada requerida y un breve an��lisis econ��mico. ABSTRACT This project consist of the dimensioning of a liquefaction process in an offshore plant to produce liquefied natural, using only N2 as refrigerant in the cooling cycles to avoid potential hazards of mixed hydrocarbon refrigerants. The process was designed to accommodate 35.23 kg/s (roughly 1 MTPA) of raw natural gas feed without separation of LPG, and fits within all parameters required in the process specifications. The plant has been designed with the computer tool Aspen Plus. The floating production, storage and offloading system for liquefied natural gas (LNGFPSO), is a new conceptual unit and an effective and realistic way for exploitation, recovery, storage, transportation and end-use applications of marginal gas fields and offshore associated-gas resources. The following report details the process, equipment needs and estimated costs, approximated power requirements, and a brief economic analysis.

Recuperaci��n secundaria en campos de petr��leo y su conversi��n en almacenamientos subterr��neos de gas natural

El objetivo de este proyecto es estudiar la recuperaci��n secundaria de petr��leo de la capa sureste Ayoluengo del campo Ayoluengo, Burgos (Espa��a), y su conversi��n en un almacenamiento subterr��neo de gas. La capa Ayoluengo se ha considerado como una capa inclinada de 60 km por 10 km de superficie por 30 m de espesor en el que se han perforado 20 pozos, y en donde la recuperaci��n primaria ha sido de un 19%. Se ha realizado el ajuste hist��rico de la recuperaci��n primaria de gas, petr��leo y agua de la capa desde el a��o 1965 al 2011. La conversi��n a almacenamiento subterr��neo de gas se ha realizado mediante ciclos de inyecci��n de gas, de marzo a octubre, y extracci��n de gas, de noviembre a febrero, de forma que se incrementa la presi��n del campo hasta alcanzar la presi��n inicial. El gas se ha inyectado y extra��do por 5 pozos situados en la zona superior de la capa. Al mismo tiempo, se ha realizado una recuperaci��n secundaria debido a la inyecci��n de gas natural de 20 a��os de duraci��n en donde la producci��n de petr��leo se realiza por 14 pozos situados en la parte inferior de la capa. Para proceder a la simulaci��n del ajuste hist��rico, conversi��n en almacenamiento y recuperaci��n secundaria se utiliz�� el simulador Eclipse100. Los resultados obtenidos fueron una recuperaci��n secundaria de petr��leo de un 9% m��s comparada con la primaria. En cuanto al almacenamiento de gas natural, se alcanz�� la presi��n inicial consiguiendo un gas ��til de 300 Mm3 y un gas colch��n de 217,3 Mm3. ABSTRACT The aim of this project is to study the secondary recovery of oil from the southeast Ayoluengo layer at the oil field Ayoluengo, Burgos (Spain), and its conversion into an underground gas storage. The Ayoluengo layer is an inclined layer of 60 km by 10km of area by 30 m gross and with 20 wells, which its primary recovery is of 19%. The history matching of the production of oil, gas and water has been carried out from the year 1965 until 2011. The conversion into an underground gas storage has been done in cycles of gas injection from March to October, and gas extraction from November to February, so that the reservoir pressure increases until it gets to the initial pressure. The gas has been injected and extracted through five well situated in the top part of the layer. At the same time, the secondary recovery has occurred due to de injection of natural gas during 20 years where the production of oil has been done through 14 wells situated in the lowest part of the layer. To proceed to the simulation of the history match, the conversion into an underground gas storage and its secondary recovery, the simulator used was Eclipse100. The results were a secondary recovery of oil of 9% more, compared to the primary recovery and concerning the underground gas storage, the initial reservoir pressure was achieved with a working gas of 300 Mm3 and a cushion gas of 217,3 Mm3.

Criterios de selecci��n de una estructura favorable para un almacenamiento de gas natural : Aplicaci��n a escala de cuenca en la Pen��nsula Ib��rica

RESUMEN Este proyecto ha tenido por objetivo el estudio de la viabilidad de instalar un nuevo almacenamiento subterr��neo de gas natural en Espa��a. Dentro de las diferentes posibilidades para emplazar el almacenamiento de gas natural se escogi�� el domo salino por ser la estructura geol��gica m��s favorable desde el punto de vista t��cnico y econ��mico. Una vez escogido el domo salino, el estudio se centr�� en localizar una ubicaci��n lo m��s favorable posible siendo el domo salino de Salinas de A��ana el elegido. Una vez elegido el domo se procedi�� al estudio de la viabilidad t��cnica de la instalaci��n; para ello se utilizaron estudios geol��gicos, gavim��tricos y sondeos. Tras estos estudios se concluy�� que en el domo salino de Salinas de A��ana es posible la instalaci��n de un almacenamiento subterr��neo de gas natural y se procedi�� a la caracterizaci��n del almacenamiento. ABSTRACT This project has considered of installing a new underground natural gas storage in Spain. Among the different possibilities to place a natural gas storage, the salt dome was chosen because it was the geological strucutrure where the project was easier and more interesting economically. After that the study focused on looking for the location as favorable as possible. The best place was the salt dome of Salinas de A��ana. Before the salt dome of Salinas de A��ana was chosen this project tried to know if the setting-up of a natural gas storage is technical feasibility. For that were used geological studies, gravity studies and drillings. These studies concluded that is possible the setting-up and the study tried to describe technically this storage.

Analysis of the Behaviour of Biofuel-Fired Gas Turbine Power Plants

The utilisation of biofuels in gas turbines is a promising alternative to fossil fuels for power generation. It would lead to significant reduction of CO2 emissions using an existing combustion technology, although significant changes seem to be needed and further technological development is necessary. The goal of this work is to perform energy and exergy analyses of the behaviour of gas turbines fired with biogas, ethanol and synthesis gas (bio-syngas), compared with natural gas. The global energy transformation process (i.e. from biomass to electricity) has also been studied. Furthermore, the potential reduction of CO2 emissions attained by the use of biofuels has been determined, considering the restrictions regarding biomass availability. Two different simulation tools have been used to accomplish the aims of this work. The results suggest a high interest and the technical viability of the use of Biomass Integrated Gasification Combined Cycle (BIGCC) systems for large scale power generation.

Gesti��n del boil off gas en la planta de regasificaci��n de Cartagena

Este proyecto trata sobre la gesti��n del boil-off gas, o BOG (vapor de gas natural que se produce en las instalaciones de gas natural licuado de las plantas de regasificaci��n), generado en la planta de regasificaci��n de Gas Natural Licuado de Cartagena, tanto en las situaciones en las que se opera por debajo del m��nimo t��cnico, como en las cargas y descargas de buques, en las cuales se ha de gestionar una cantidad del boil-off adicional. Para recuperar el boil-off, las plantas cuentan con un relicuador (intercambiador de calor) en el que el BOG es relicuado por el GNL que se env��a a los vaporizadores para ser regasificado y emitido a la red. De forma complementaria cuentan tambi��n con una antorcha/venteo donde se quema el exceso de boil-off que no puede ser tratado por el relicuador. Se procede a un an��lisis de la situaci��n actual, y de c��mo la baja demanda de regasificaci��n dificulta la gesti��n del boil-off. Se simula el proceso de relicuaci��n actual en distintas situaciones de operaci��n. Ante la situaci��n de baja demanda, ha aumentado considerablemente el n��mero de d��as en los que las plantas espa��olas en general, y la planta de Cartagena en particular, operan por debajo del m��nimo t��cnico, que es el nivel de producci��n m��nimo para recuperar todo el boil-off generado en cualquier situaci��n de operaci��n al tiempo que mantiene en fr��o todas las instalaciones, y garantiza el 100% de disponibilidad inmediata del resto de los equipos en condiciones de seguridad de funcionamiento estable. Esta situaci��n supone inconvenientes tanto operativos como medioambientales y acarrea mayores costes econ��micos, a los cuales da soluci��n el presente proyecto, decidiendo qu�� alternativa t��cnica es la m��s adecuada y defini��ndola. Abstract This project is about the management of the boil-off gas (BOG), natural vapour gas that is produced in liquefied natural gas (LNG) regasification plants. Specifically, the study is focused on the LNG regasification plant located in Cartagena, when it operates both below the technical minimum level of regasification and in the loading/unloading of LNG carriers, situations when it is needed to handle additional BOG. In order to make the most of BOG, the plants have a re-condenser (heat exchanger). Here, the BOG is re-liquefied by the LNG that is submitted to the vaporizers and delivered to the grid. The plants also have a flare/vent where the excess of BOG that cannot be treated by the re-condenser is burned. An analysis of the current situation of the demand is performed, evaluating how low markets demand for regasification difficult the BOG management. Besides, it is simulated the current re-liquefaction operating in different environments. Due to the reduction of the demand for natural gas, the periods when Spanish LNG regasification plants (and particularly the factory of Cartagena) are operating below the technical minimum level of regasification are more usual. This level is the minimum production to recover all the BOG generated in any operating situation while maintaining cold all facilities, fully guaranteeing the immediate availability from other equipment in a safely and stable operation. This situation carries both operational and environmental drawbacks, and leads to higher economic costs. This project aims to solve this problem, presenting several technical solutions and deciding which is the most appropriate.

Evaluaci��n ambiental de las tecnolog��as de recuperaci��n de gas en formaciones no convencionales

Este proyecto pretende ofrecer una visi��n general de una de las tecnolog��as m��s actuales de recuperaci��n de gas en formaciones no convencionales: fracturaci��n hidr��ulica o ���fracking���. El proyecto est�� motivado por la necesidad de responder a diferentes cuestiones sobre los efectos ambientales, sociales y en la salud humana derivados de la utilizaci��n de esa tecnolog��a. Ofrece, adem��s, una descripci��n del proceso y utilizaci��n de la tecnolog��a haciendo especial menci��n de los riesgos inherentes de su uso, aunque tambi��n se intenta establecer una v��a de aceptaci��n para su desarrollo cuyo fin ��ltimo, a parte de los beneficios econ��micos de quienes la usan, es el de posibilitar la transici��n hacia el uso de unos recursos (energ��as f��siles de extracci��n no convencional) que requieren de dichas t��cnicas para mantener, a lo largo del tiempo, el suministro de una energ��a que se supone m��s respetuosa con el medio ambiente: el gas natural. En primer lugar se expone, a modo introductorio, la necesidad de utilizaci��n de nuevas t��cnicas de estimulaci��n de pozos y su utilizaci��n para satisfacer las necesidades energ��ticas mundiales en los pr��ximos a��os. A continuaci��n se hace una revisi��n del marco regulatorio aplicable al gas no convencional. Seguidamente, se hace una descripci��n de los recursos y fuentes no convencionales de gas y la descripci��n del proceso de fracturaci��n hidr��ulica. Se analizan los incidentes relacionados con su desarrollo y las posibilidades y mecanismos que pueden adoptarse para reducirlos. Finalmente, se proponen v��as alternativas basadas en las mejores t��cnicas aplicables al uso de la tecnolog��a, cuya finalidad sea la mayor consideraci��n ambiental posible y el menor riesgo posible en la salud de las personas. ABSTRACT This project aims to provide an overview of the latest technologies in gas recovery unconventional formations: hydraulic fracturing or "fracking". The project is motivated by the need to respond to various questions on the environmental, social and human health arising from the use of this technology. It also offers a description of the process and use of technology with special mention of the inherent risks of their use, but also tries to establish a path of acceptance for development whose ultimate goal, apart from the economic benefits of those who use is of enabling the transition to the use of certain resources (fossil energy extraction unconventional) which require such techniques to maintain, over time, of an energy supply which is more environmentally friendly: natural gas. First discussed the need to use new well stimulation techniques and their use to meet the world's energy needs in the coming years. Below is a review of the regulatory framework applicable to unconventional gas. Next, there is a description of resources and unconventional sources of gas, and the description of the process of hydraulic fracturing. We analyze the incidents related to its development and the possibilities and mechanisms that can be taken to reduce them. Finally, we suggest alternative routes based on the best techniques applicable to the use of technology, aiming at the highest possible environmental consideration and the least possible risk to the health of people.

Identificaci��n de los riesgos ambientales y sanitarios de la producci��n de gas mediante fracturaci��n hidr��ulica y bases para una propuesta metodol��gica de vulnerabilidad de las aguas subterr��neas

Hasta ahora, la gran mayor��a de los recursos explotados de gas natural proced��an de acumulaciones convencionales de gas aislado y de gas asociado y disuelto en el petr��leo. Sin embargo, el gas natural se encuentra tambi��n en yacimientos que, debido a su baja porosidad y permeabilidad, tienen unas caracter��sticas que hacen que hasta muy recientemente no hayan sido econ��micamente rentables y que s��lo puedan ser explotados mediante t��cnicas no convencionales, dando lugar al denominado gas no convencional. Las t��cnicas utilizadas para su extracci��n son la fracturaci��n hidr��ulica o ���fracking��� y la perforaci��n horizontal. Entre los diversos tipos de gas no convencional, es de prever que el gas de pizarra sea el que sufra mayor desarrollo a medio plazo en nuestro pa��s, por lo que se est��n generando grandes debates, debido al riesgo de contaminaci��n de las aguas superficiales y subterr��neas del entorno, provocados por la elevada cantidad de agua utilizada, los aditivos empleados, los fluidos de retorno, por la alteraci��n del medio f��sico, as�� como por la dificultad de monitorizaci��n de estos procesos. En este proyecto se identifican los riesgos ambientales y sanitarios asociados a la extracci��n de gas no convencional. El trabajo se basa principalmente en experiencias ocurridas en pa��ses donde el fracking se ha convertido en una pr��ctica habitual. Se trata adem��s de establecer las bases necesarias para la estimaci��n de la vulnerabilidad de los acu��feros frente a la contaminaci��n inducida por la fracturaci��n hidr��ulica. Abstract Until now, most of the natural gas resources exploited were from isolated conventional gas accumulations and associated and dissolved gas in oil. However, the natural gas is also in reservoirs that, due to their low porosity and permeability, have characteristics that make until recently not been economically profitable and can be exploited only by unconventional techniques, leading to the so called unconventional gas. The techniques used for extraction are hydraulic fracturing or "fracking" and horizontal drilling. Among the various types of unconventional gas, it is expected that shale gas is the suffering greater medium-term development in our country, so it is generating much debate, due to the risks of contamination in surface waters and subterranean environment, caused by the high amount of water used, the additives used, the return fluid, by altering the physical environment, and the difficulty of monitoring these processes. In this project identifies the environmental and health risks associated with unconventional gas extraction. The work is mainly based on experiences that occurred in countries where fracking has become a common practice. This is for establish the necessary basis for estimating the vulnerability of aquifers from contamination induced by hydraulic fracturing.

Optimizaci��n del coste de aprovisionamiento de gas en el mercado mayorista espa��ol para una comercializadora

Los precios de compra de gas natural en el mercado mayorista espa��ol son los m��s altos de toda Europa. Este escenario provoca que haya que buscar alternativas para minimizar los costes de aprovisionamiento para una comercializadora de gas. En este proyecto se analizan distintas oportunidades de compra de gas en los mercados europeos y su importaci��n al sistema gasista espa��ol para el suministro final a clientes, con el fin de optimizar los costes del gas natural para una comercializadora. En la b��squeda de nuevas oportunidades se incluye tambi��n un an��lisis del impacto econ��mico en el mercado, de la producci��n de ���shale gas��� en Espa��a a medio - largo plazo. ABSTRACT The gas prices in the Spanish gas market are the highest in Europe. This scenario leads the Spanish gas trading companies to look for alternatives to minimize gas supply costs. In this project it is analyzed different opportunities of gas supply in the European markets and the gas import to the Spanish gas system, in order to optimize the costs of the natural gas for a gas trading company. Along with this, it is also studied, the economic impact of the ���shale gas��� production in Spain in a medium - long term on the Spanish gas market

CO2 emissions from a spark ignition engine operatin on natural-hydrogen blends (HCNG)

The addition of hydrogen to natural gas could be a short-term alternative to today���s fossil fuels, as greenhouse gas emissions may be reduced. The aim of this study is to evaluate the emissions and performance of a spark ignition engine fuelled by pure natural gas, pure hydrogen, and different blends of hydrogen and natural gas (HCNG). Increasing the hydrogen fraction leads to variations in cylinder pressure and CO2 emissions. In this study, a combustion model based on thermodynamic equations is used, considering separate zones for burned and unburned gases. The results show that the maximum cylinder pressure rises as the fraction of hydrogen in the blend increases. The presence of hydrogen in the blend leads to a decrease in CO2 emissions. Due to the properties of hydrogen, leaner fuel���air mixtures can be used along with the appropriate spark timing, leading to an improvement in engine emissions with no loss of performance.

Co2 capture in power plants-using the oxy-combustion principle

In the C02 capture from power generation, the energy penalties for the capture are one of the main challenges. Nowadays, the post-combustion methods have energy penalties 10wer than the oxy combustion and pre-combustion technologies. One of the main disadvantages of the post combustion method is the fact that the capture ofC02at atmospheric pressure requires quite big equipment for the high flow rates of flue gas, and the 10w partial pressure of the CO2generates an important 10ss of energy. The A1lam cyc1e presented for NETPOWER gives high efficiencies in the power production and 10w energy penalties. A simulation of this cyc1e is made together with a simulation of power plants with pre-combustion and post-combustion capture and without capture for natural gas and forcoa1. The simulations give 10wer efficiencies than the proposed for NETPOWER For natural gas the efficiency is 52% instead of the 59% presented, and 33% instead of51% in the case of using coal as fuel. Are brought to light problems in the CO2compressor due the high flow ofC02that is compressed unti1300 bar to be recyc1ed into the combustor.