Roteiro Tecnol��gico (roadmap) da Capta����o, Utiliza����o e Armazenamento de Di��xido de Carbono (CCUS) em Portugal

O objetivo primordial deste trabalho foi estabelecer um roteiro tecnol��gico para aplica����o das tecnologias de ���Capta����o, Utiliza����o e Sequestra����o de Carbono - CCUS��� em Portugal. Para o efeito procedeu-se �� identifica����o da origem das maiores fontes emissoras estacion��rias industriais de CO2, adotando como crit��rio o valor m��nimo de 1��105 ton CO2/ano e limitado apenas ao territ��rio continental. Com base na informa����o recolhida e referente aos dados oficiais mais recentes (ano de 2013), estimou-se que o volume de emiss��es industriais de CO2 poss��vel de captar em Portugal, corresponde a cerca de 47 % do valor global das emiss��es industriais, sendo oriundo de tr��s setores de atividade industrial: produ����o de cimento, de pasta de papel e centrais termoel��tricas a carv��o. A maioria das grandes fontes emissoras industriais localiza-se no litoral do pa��s, concentrando-se entre Aveiro e Sines. Pelas condicionantes geogr��ficas do pa��s e, sobretudo pela vantagem de j�� existir uma rede de gasodutos para o transporte de g��s natural, com as respetivas infraestruturas de apoio associadas, admitiu-se que o cen��rio mais favor��vel para o transporte do CO2 captado ser�� a cria����o de um sistema de transporte por gasoduto espec��fico para o CO2. Como crit��rio de compatibiliza����o da proximidade das fontes emissoras de CO2 com potenciais locais para o armazenamento geol��gico das correntes captadas, adotou-se a dist��ncia m��xima de 100 km, considerada adequada perante a dimens��o do territ��rio nacional e as caracter��sticas do tecido industrial nacional. Efetuou-se a revis��o das tecnologias de capta����o de CO2 dispon��veis, quer comercialmente, quer em n��veis avan��ados de demonstra����o e procedeu-se �� an��lise explorat��ria da adequa����o desses diferentes m��todos de capta����o a cada um dos setores de atividade industrial previamente identificados com emiss��es de CO2 suscet��veis de serem captadas. Na perspetiva da melhor integra����o dos processos, esta an��lise preliminar tomou em considera����o as caracter��sticas das misturas gasosas, assim como o contexto industrial correspondente e o processo produtivo que lhe d�� origem. As possibilidades de utiliza����o industrial do CO2 sujeito �� capta����o no pa��s foram tratadas neste trabalho de forma gen��rica dado que a identifica����o de oportunidades reais para a utiliza����o de correntes de CO2 captadas exige uma an��lise de compatibiliza����o das necessidades efetivas de utiliza����o de CO2 por parte de potenciais utilizadores industriais que carece da caracteriza����o pr��via das propriedades dessas correntes. Este �� um tipo de an��lise muito espec��fico que pressup��e o interesse m��tuo de diferentes intervenientes: agentes emissores de CO2, operadores de transporte e, principalmente, potenciais utilizadores de CO2 como: mat��ria-prima para a s��ntese de compostos, solvente de extra����o supercr��tica na ind��stria alimentar ou farmac��utica, agente corretor de pH em tratamento de efluentes, biofixa����o por fotoss��ntese, ou outra das aplica����es poss��veis identificadas para o CO2 captado. A ��ltima etapa deste estudo consistiu na avalia����o das possibilidades de armazenamento geol��gico do CO2 captado e envolveu a identifica����o, nas bacias sedimentares nacionais, de forma����es geol��gicas com caracter��sticas reconhecidas como sendo boas indica����es para o armazenamento de CO2 de forma permanente e em seguran��a. Seguiu-se a metodologia preconizada por organiza����es internacionais aplicando �� situa����o nacional, crit��rios de sele����o e de seguran��a que se encontram reconhecidamente definidos. A adequa����o para o armazenamento de CO2 das forma����es geol��gicas pr��-selecionadas ter�� que ser comprovada por estudos adicionais que complementem os dados j�� existentes sobre as caracter��sticas geol��gicas destas forma����es e, mais importante ainda, por testes laboratoriais e ensaios de inje����o de CO2 que possam fornecer informa����o concreta para estimar a capacidade de sequestra����o e de reten����o de CO2 nestas forma����es e estabelecer os modelos geol��gicos armazenamento que permitam identificar e estimar, de forma concreta e objetiva, os riscos associados �� inje����o e armazenamento de CO2.

Techno-economic analysis of three HVAC retrofitting options

Accounting for around 40% of the total final energy consumption, the building stock is an important area of focus on the way to reaching the energy goals set for the European Union. The relatively small share of new buildings makes renovation of existing buildings possibly the most feasible way of improving the overall energy performance of the building stock. This of course involves improvements on the climate shell, for example by additional insulation or change of window glazing, but also installation of new heating systems, to increase the energy efficiency and to fit the new heat load after renovation. In the choice of systems for heating, ventilation and air conditioning (HVAC), it is important to consider their performance for space heating as well as for domestic hot water (DHW), especially for a renovated house where the DHW share of the total heating consumption is larger. The present study treats the retrofitting of a generic single family house, which was defined as a reference building in a European energy renovation project. Three HVAC retrofitting options were compared from a techno-economic point of view: A) Air-to-water heat pump (AWHP) and mechanical ventilation with heat recovery (MVHR), B) Exhaust air heat pump (EAHP) with low-temperature ventilation radiators, and C) Gas boiler and ventilation with MVHR. The systems were simulated for houses with two levels of heating demand and four different locations: Stockholm, Gdansk, Stuttgart and London. They were then evaluated by means of life cycle cost (LCC) and primary energy consumption. Dynamic simulations were done in TRNSYS 17. In most cases, system C with gas boiler and MVHR was found to be the cheapest retrofitting option from a life cycle perspective. The advantage over the heat pump systems was particularly clear for a house in Germany, due to the large discrepancy between national prices of natural gas and electricity. In Sweden, where the price difference is much smaller, the heat pump systems had almost as low or even lower life cycle costs than the gas boiler system. Considering the limited availability of natural gas in Sweden, systems A and B would be the better options. From a primary energy point of view system A was the best option throughout, while system B often had the highest primary energy consumption. The limited capacity of the EAHP forced it to use more auxiliary heating than the other systems did, which lowered its COP. The AWHP managed the DHW load better due to a higher capacity, but had a lower COP than the EAHP in space heating mode. Systems A and C were notably favoured by the air heat recovery, which significantly reduced the heating demand. It was also seen that the DHW share of the total heating consumption was, as expected, larger for the house with the lower space heating demand. This confirms the supposition that it is important to include DHW in the study of HVAC systems for retrofitting.

Formula����o de bet��o autocompact��vel com res��duos de pedreiras do Alentejo: Aproveitamento de res��duos no fabrico do bet��o

Os bet��es autocompact��veis (BAC) s��o bet��es que se definem pela capacidade de fluir no interior das cofragens, preenchendo-as e envolvendo as armaduras s�� por ac����o do seu pr��prio peso, sem bloqueio dos agregados e mantendo-se homog��neo em todo o seu volume. As adi����es activas do tipo II nomeadamente as cinzas volantes, utilizadas na fabrica����o do BAC ir��o escassear no futuro pelo facto de provirem da queima do carv��o da qual resulta uma quantidade elevada de C02. Para minimizar estas emiss��es, o carv��o come��a a ser substitu��do por g��s natural. Mas, como o BAC necessita duma grande quantidade de finos, h�� necessidade de encontrar outros subprodutos que a substituam. Tendo em conta o que atr��s se afirma introduziram-se na fabrica����o do BAC res��duos de pedreira do Alentejo, identificaram-se as suas caracter��sticas no estado fresco e no estado endurecido. Este estudo teve tamb��m em conta o factor econ��mico da sua produ����o. /ABSTRACT: Self-Compacting (SCC) is concrete which may be defined by the ability to flow inside the formwork, filling them and involving the reinforcements only by action of its own weight, without blocking and maintaining uniformity throughout its volume. Type II additions, as fly ash, are used in the manufacture of SCC. The supply of fly ash in the future will be difficult because they come from the burning of coal resulting in a high amount of C02. To minimize these emissions, coal is being replaced by natural gas. But, as the BAC requires a large amount of fine materials, the formulation of SCC requires other fine products. Having this in mind, the use of waste from Alentejo quarries in concrete was tested. The characteristics of SCC with waste material were identified in fresh and hardened state. This study also took into account the economic factor of production.

Does Final Energy Demand in Portugal Exhibit Long Memory? A Fractional Integration Analysis

In this paper, we measure the degree of fractional integration in final energy demand in Portugal using an ARFIMA model with and without adjustments for seasonality. We consider aggregate energy demand as well as final demand for petroleum, electricity, coal, and natural gas. Our findings suggest the presence of long memory in all of the components of energy demand. All fractional-difference parameters are positive and lower than 0.5 indicating that the series are stationary, although with mean reversion patterns slower than in the typical short-run processes. These results have important implications for the design of energy policies. As a result of the long-memory in final energy demand, the effects of temporary policy shocks will tend to disappear slowly. This means that even transitory shocks have long lasting effects. Given the temporary nature of these effects, however, permanent effects on final energy demand require permanent policies. This is unlike what would be suggested by the more standard, but much more limited, unit root approach, which would incorrectly indicate that even transitory policies would have permanent effects

Synthesis, Modification and Characterization of Polymeric Membranes for CO2 Separation

This doctorate focused on the development of dense polymeric membranes for carbon capture, mostly in post combustion applications, and for natural gas sweetening. The work was supported by the European Project NANOMEMC2 funded under H2020 program. Different materials have been investigated, that rely on two main transport mechanisms: the solution-diffusion and the facilitated transport. In both cases, proper nano-fillers have been added to the matrix, in order to boost the mechanical and permselective properties of the membranes. Facilitated transport membranes were based on the use of was polyvinylamine (PVAm), as main matrix with fixed-site carriers, and L-Arginine as mobile carrier; the filler, used mostly as reinforcer, was carboxymethylated nanocellulose (cNFC). Humid test showed interesting results, and especially the blend made of PVAm/cNFC/Arg in weight ratio 27,5/27,5/45 crossed the Robeson CO2/N2 upper bound, representing current state of the art membranes, with a CO2 permeability of 271 Barrer and CO2/N2 selectivity of 70. Solution diffusion membranes were based on Pebax��2533 matrix which was added with three different graphene oxide (GO)-based materials, namely pristine GO, Porous Graphene Oxide (PGO) and a GO functionalized with polyetheramine (PEAGO). All of them provided a modest but clear increment of permeability of the Pebax matrix, from plus 2% (GO) to plus 8% (PGO), with no change in selectivity. The gas tested with this type of composites were CO2 and N2, for Post combustion capture applications. Pebax��2533 was also chemically modified, obtaining the product called ���Benzoyl-P2533���, that was fully characterized, and tested in term of permeation using five gas: CO2, N2, CH4, O2, and He. Modified material showed an increment of the overall permeability of the material of a fair 10% for all gases tested, apart from helium, that increased of almost 50%.

Ultra-Low Temperature Partial Oxidation: Detailed Kinetics, Safety, and Environmental Issues

The innovation in several industrial sectors has been recently characterized by the need for reducing the operative temperature either for economic or environmental related aspects. Promising technological solutions require the acquisition of fundamental-based knowledge to produce safe and robust systems. In this sense, reactive systems often represent the bottleneck. For these reasons, this work was focused on the integration of chemical (i.e., detailed kinetic mechanism) and physical (i.e., computational fluid dynamics) models. A theoretical-based kinetic mechanism mimicking the behaviour of oxygenated fuels and their intermediates under oxidative conditions in a wide range of temperature and pressure was developed. Its validity was tested against experimental data collected in this work by using the heat flux burner, as well as measurements retrieved from the current literature. Besides, estimations deriving from existing models considered as the benchmark in the combustion field were compared with the newly generated mechanism. The latter was found to be the most accurate for the investigated conditions and fuels. Most influential species and reactions on the combustion of butyl acetate were identified. The corresponding thermodynamic parameter and rate coefficients were quantified through ab initio calculations. A reduced detailed kinetic mechanism was produced and implemented in an open-source computational fluid dynamics model to characterize pool fires caused by the accidental release of aviation fuel and liquefied natural gas, at first. Eventually, partial oxidation processes involving light alkenes were optimized following the quick, fair, and smoot (QFS) paradigm. The proposed procedure represents a comprehensive and multidisciplinary approach for the construction and validation of accurate models, allowing for the characterization of developing industrial sectors and techniques.

Modelling of ORC components and systems for low-medium temperature heat recovery applications with reduced environmental impact

Although its great potential as low to medium temperature waste heat recovery (WHR) solution, the ORC technology presents open challenges that still prevent its diffusion in the market, which are different depending on the application and the size at stake. Focusing on the micro range power size and low temperature heat sources, the ORC technology is still not mature due to the lack of appropriate machines and working fluids. Considering instead the medium to large size, the technology is already available but the investment is still risky. The intention of this thesis is to address some of the topical themes in the ORC field, paying special attention in the development of reliable models based on realistic data and accounting for the off-design performance of the ORC system and of each of its components. Concerning the ���Micro-generation��� application, this work: i) explores the modelling methodology, the performance and the optimal parameters of reciprocating piston expanders; ii) investigates the performance of such expander and of the whole micro-ORC system when using Hydrofluorocarbons as working fluid or their new low GWP alternatives and mixtures; iii) analyzes the innovative ORC reversible architecture (conceived for the energy storage), its optimal regulation strategy and its potential when inserted in typical small industrial frameworks. Regarding the ���Industrial WHR��� sector, this thesis examines the WHR opportunity of ORCs, with a focus on the natural gas compressor stations application. This work provides information about all the possible parameters that can influence the optimal sizing, the performance and thus the feasibility of installing an ORC system. New WHR configurations are explored: i) a first one, relying on the replacement of a compressor prime mover with an ORC; ii) a second one, which consists in the use of a supercritical CO2 cycle as heat recovery system.

Optimization and development of low environmental impact propulsion systems

The aim of the Ph.D. research project was to explore Dual Fuel combustion and hybridization. Natural gas-diesel Dual Fuel combustion was experimentally investigated on a 4-Stroke, 2.8 L, turbocharged, light-duty Diesel engine, considering four operating points in the range between low to medium-high loads at 3000 rpm. Then, a numerical analysis was carried out using a customized version of the KIVA-3V code, in order to optimize the diesel injection strategy of the highest investigated load. A second KIVA-3V model was used to analyse the interchangeability between natural gas and biogas on an intermediate operating point. Since natural gas-diesel Dual Fuel combustion suffers from poor combustion efficiency at low loads, the effects of hydrogen enriched natural gas on Dual Fuel combustion were investigated using a validated Ansys Forte model, followed by an optimization of the diesel injection strategy and a sensitivity analysis to the swirl ratio, on the lowest investigated load. Since one of the main issues of Low Temperature Combustion engines is the low power density, 2-Stroke engines, thanks to the double frequency compared to 4-Stroke engines, may be more suitable to operate in Dual Fuel mode. Therefore, the application of gasoline-diesel Dual Fuel combustion to a modern 2-Stroke Diesel engine was analysed, starting from the investigation of gasoline injection and mixture formation. As far as hybridization is concerned, a MATLAB-Simulink model was built to compare a conventional (combustion) and a parallel-hybrid powertrain applied to a Formula SAE race car.

Two stroke cycle, novel combustion concepts and electrification for a new generation of internal combustion engines

The pursuit of decarbonization and increased efficiency in internal combustion engines (ICE) is crucial for reducing pollution in the mobility sector. While electrification is a long-term goal, ICE still has a role to play if coupled with innovative technologies. This research project explores various solutions to enhance ICE efficiency and reduce emissions, including Low Temperature Combustion (LTC), Dual fuel combustion with diesel and natural gas, and hydrogen integration. LTC methods like Dual fuel and Reactivity Controlled Compression Ignition (RCCI) show promise in lowering emissions such as NOx, soot, and CO2. Dual fuel Diesel-Natural Gas with hydrogen addition demonstrates improved efficiency, especially at low loads. RCCI Diesel-Gasoline engines offer increased Brake Thermal Efficiency (BTE) compared to standard diesel engines while reducing specific NOx emissions. The study compares 2-Stroke and 4-Stroke engine layouts, optimizing scavenging systems for both aircraft and vehicle applications. CFD analysis enhances specific power output while addressing injection challenges to prevent exhaust short circuits. Additionally, piston bowl shape optimization in Diesel engines running on Dual fuel (Diesel-Biogas) aims to reduce NOx emissions and enhance thermal efficiency. Unconventional 2-Stroke architectures, such as reverse loop scavenged with valves for high-performance cars, opposed piston engines for electricity generation, and small loop scavenged engines for scooters, are also explored. These innovations, alongside ultra-lean hydrogen combustion, offer diverse pathways toward achieving climate neutrality in the transport sector.

Nonlinear modelling of non-structural masonry walls under a low-intensity earthquake motion: calibration through a parametric study

This thesis aims to understand the behavior of a low-rise unreinforced masonry building (URM), the typical residential house in the Netherlands, when subjected to low-intensity earthquakes. In fact, in the last decades, the Groningen region was hit by several shallow earthquakes caused by the extraction of natural gas. In particular, the focus is addressed to the internal non-structural walls and to their interaction with the structural parts of the building. A simple and cost-efficient 2D FEM model is developed, focused on the interfaces representing mortar layers that are present between the non-structural walls and the rest of the structure. As a reference for geometries and materials, it has been taken into consideration a prototype that was built in full-scale at the EUCENTRE laboratory of Pavia (Italy). Firstly, a quasi-static analysis is performed by gradually applying a prescribed displacement on the roof floor of the structure. Sensitivity analyses are conducted on some key parameters characterizing mortar. This analysis allows for the calibration of their values and the evaluation of the reliability of the model. Successively, a transient analysis is performed to effectively subject the model to a seismic action and hence also evaluate the mechanical response of the building over time. Moreover, it was possible to compare the results of this analysis with the displacements recorded in the experimental tests by creating a model representing the entire considered structure. As a result, some conditions for the model calibration are defined. The reliability of the model is then confirmed by both the reasonable results obtained from the sensitivity analysis and the compatibility of the values obtained for the top displacement of the roof floor of the experimental test, and the same value acquired from the structural model.

Gas Natural Fenosa: Equity research

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA ��� School of Business and Economics

Modelo de comercializaci��n del gas natural en la zona metropolitana de Monterrey. N.L. (bajo un entorno global competitivo) [por] Artidoro Gracia Vilches.

Tesis (Maestro en Administraci��n de Empresas con Especialidad en Mercadotecnia) U.A.N.L.

Pre-procesamiento de un problema de optimizaci��n de redes de gas natural

Tesis ( Maestro en Ciencias en Ingenier��a de Sistemas) U.A.N.L.

Una metodolog��a de soluci��n basada en programaci��n din��mica no secuencial y b��squeda Tab�� para la operaci��n eficiente de sistemas de transporte de gas natural en estado estable

Tesis (Maestro en Ciencias en Ingenier��a de Sistemas) U.A.N.L.

Operaci��n eficiente de sistemas de transporte de gas natural mediante el m��todo de gradiente reducido generalizado

UANL