Resistência à fadiga de tubo API 5L X65 cladeado e soldado circunferencialmente com eletrodos de Inconel® 625

As recentes descobertas de petróleo e gás na camada do Pré-sal representam um enorme potencial exploratório no Brasil, entretanto, os desafios tecnológicos para a exploração desses recursos minerais são imensos e, consequentemente, têm motivado o desenvolvimento de estudos voltados a métodos e materiais eficientes para suas produções. Os tubos condutores de petróleo e gás são denominados de elevadores catenários ou do inglês \"risers\", e são elementos que necessariamente são soldados e possuem fundamental importância nessa cadeia produtiva, pois transportam petróleo e gás natural do fundo do mar à plataforma, estando sujeitos a carregamentos dinâmicos (fadiga) durante sua operação. Adicionalmente, um dos problemas centrais à produção de óleo e gás das reservas do Pré-Sal está diretamente associado a meios altamente corrosivos, tais como H2S e CO2. Uma forma mais barata de proteção dos tubos é a aplicação de uma camada de um material metálico resistente à corrosão na parte interna desses tubos (clad). Assim, a união entre esses tubos para formação dos \"risers\" deve ser realizada pelo emprego de soldas circunferenciais de ligas igualmente resistentes à corrosão. Nesse contexto, como os elementos soldados são considerados possuir defeitos do tipo trinca, para a garantia de sua integridade estrutural quando submetidos a carregamentos cíclicos, é necessário o conhecimento das taxas de propagação de trinca por fadiga da solda circunferencial. Assim, neste trabalho, foram realizados ensaios de propagação de trinca por fadiga na região da solda circunferencial de Inconel® 625 realizada em tubo de aço API 5L X65 cladeado, utilizando corpos de prova do tipo SEN(B) (Single Edge Notch Bending) com relações entre espessura e largura (B/W) iguais a 0,5, 1 e 2. O propósito central deste trabalho foi de obter a curva da taxa de propagação de trinca por fadiga (da/dN) versus a variação do fator de intensidade de tensão (ΔK) para o metal de solda por meio de ensaios normatizados, utilizando diferentes técnicas de acompanhamento e medição da trinca. A monitoração de crescimento da trinca foi feita por três técnicas: variação da flexibilidade elástica (VFE), queda de potencial elétrico (QPE) e análise de imagem (Ai). Os resultados mostraram que as diferentes relações B/W utilizadas no estudo não alteraram significantemente as taxas de propagação de trinca por fadiga, respeitado que a propagação aconteceu em condições de escoamento em pequena escala na frente da trinca. Os resultados de propagação de trinca por fadiga permitiram a obtenção das regiões 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 equação de Paris-Erdogan foram respectivamente iguais a 1,55 x10-10 [(mm/ciclo)/(MPa.m1/2)m] e 4,15. A propagação de trinca no metal de solda deu-se por deformação plástica, com a formação de estrias de fadiga.

Transmission and Transport of Energy in the Western U.S. and Canada: A Law and Policy Road Map

This collection of short essays arose from the inaugural meeting of the Idaho Symposium on Energy in the West, which was held in November, 2014. The topic for this first Symposium was Transmission and Transport of Energy in the Western U.S. and Canada: A Law and Policy Road Map. The essays in this collection provide a notable introduction to the major energy issues facing the West today. Topics include: building a resilient legal architecture for western energy production; natural gas flaring; transmission planning for wind energy; utilities and rooftop solar; special considerations for western states and the Clean Power Plan; the Clean Power Plan's implications for the western grid; siting renewable energy on public lands; and implications of utility reform in New York and Hawaii for the Northwest.

Integration of Sustainable Development Principles into a Community Park

Characteristics of six operating hot spring recreational facilities were reviewed to identify opportunities for integrating a range of sustainable design and operation approaches into a community park. Potential operating cost savings were evaluated for a conceptual landscape project, bathhouse project, and swimming pool project that reduced the use of electricity, natural gas, water, the discharge of water, and solid waste generation. The projects showed a combined cost savings of approximately $40,000 per year by adopting passive solar design, energy efficient lighting, native vegetation, water efficient fixtures, and a natural swimming pool. The greatest potential operating cost reductions were observed for cutbacks in the use of swimming pool water and reductions in natural gas needed for building and swimming pool heating.

NaOH and KOH for preparing activated carbons used in energy and environmental applications

Alkaline hydroxides, especially sodium and potassium hydroxides, are multi-million-ton per annum commodities and strong chemical bases that have large scale applications. Some of them are related with their consequent ability to degrade most materials, depending on the temperature used. As an example, these chemicals are involved in the manufacture of pulp and paper, textiles, biodiesels, soaps and detergents, acid gases removal (e.g., SO2) and others, as well as in many organic synthesis processes. Sodium and potassium hydroxides are strong and corrosive bases, but they are also very stable chemicals that can melt without decomposition, NaOH at 318ºC, and KOH at 360ºC. Hence, they can react with most materials, even with relatively inert ones such as carbon materials. Thus, at temperatures higher than 360ºC these melted hydroxides easily react with most types of carbon-containing raw materials (coals, lignocellulosic materials, pitches, etc.), as well as with most pure carbon materials (carbon fibers, carbon nanofibers and carbon nanotubes). This reaction occurs via a solid-liquid redox reaction in which both hydroxides (NaOH or KOH) are converted to the following main products: hydrogen, alkaline metals and alkaline carbonates, as a result of the carbon precursor oxidation. By controlling this reaction, and after a suitable washing process, good quality activated carbons (ACs), a classical type of porous materials, can be prepared. Such carbon activation by hydroxides, known since long time ago, continues to be under research due to the unique properties of the resulting activated carbons. They have promising high porosity developments and interesting pore size distributions. These two properties are important for new applications such as gas storage (e.g., natural gas or hydrogen), capture, storage and transport of carbon dioxide, electricity storage demands (EDLC-supercapacitors-) or pollution control. Because these applications require new and superior quality activated carbons, there is no doubt that among the different existing activating processes, the one based on the chemical reaction between the carbon precursor and the alkaline hydroxide (NaOH or KOH) gives the best activation results. The present article covers different aspects of the activation by hydroxides, including the characteristics of the resulting activated carbons and their performance in some environment-related applications. The following topics are discussed: i) variables of the preparation method, such as the nature of the hydroxide, the type of carbon precursor, the hydroxide/carbon precursor ratio, the mixing procedure of carbon precursor and hydroxide (impregnation of the precursor with a hydroxide solution or mixing both, hydroxide and carbon precursor, as solids), or the temperature and time of the reaction are discussed, analyzing their effect on the resulting porosity; ii) analysis of the main reactions occurring during the activation process, iii) comparative analysis of the porosity development obtained from different activation processes (e.g., CO2, steam, phosphoric acid and hydroxides activation); and iv) performance of the prepared activated carbon materials on a few applications, such as VOC removal, electricity and gas storages.

High-Pressure Methane Storage in Porous Materials: Are Carbon Materials in the Pole Position?

Natural gas storage on porous materials (ANG) is a promising alternative to conventional on-board compressed (CNG) or liquefied natural gas (LNG). To date, Metal–organic framework (MOF) materials have apparently been the only system published in the literature that is able to reach the new Department of Energy (DOE) value of 263 cm3 (STP: 273.15 K, 1 atm)/cm3; however, this value was obtained by using the ideal single-crystal density to calculate the volumetric capacity. Here, we prove experimentally, and for the first time, that properly designed activated carbon materials can really achieve the new DOE value while avoiding the additional drawback usually associated with MOF materials (i.e., the low mechanical stability under pressure (conforming), which is required for any practical application).

Gasification and Pyrolysis of Posidonia oceanica in the Presence of Dolomite

Resumen del póster presentado en Symposium on Renewable Energy and Products from Biomass and Waste, CIUDEN (Cubillos de Sil, León, Spain), 12-13 May 2015

Retrofit of heat exchanger networks with pressure recovery of process streams at sub-ambient conditions

This paper presents a new mathematical programming model for the retrofit of heat exchanger networks (HENs), wherein the pressure recovery of process streams is conducted to enhance heat integration. Particularly applied to cryogenic processes, HENs retrofit with combined heat and work integration is mainly aimed at reducing the use of expensive cold services. The proposed multi-stage superstructure allows the increment of the existing heat transfer area, as well as the use of new equipment for both heat exchange and pressure manipulation. The pressure recovery of streams is carried out simultaneously with the HEN design, such that the process conditions (streams pressure and temperature) are variables of optimization. The mathematical model is formulated using generalized disjunctive programming (GDP) and is optimized via mixed-integer nonlinear programming (MINLP), through the minimization of the retrofit total annualized cost, considering the turbine and compressor coupling with a helper motor. Three case studies are performed to assess the accuracy of the developed approach, including a real industrial example related to liquefied natural gas (LNG) production. The results show that the pressure recovery of streams is efficient for energy savings and, consequently, for decreasing the HEN retrofit total cost especially in sub-ambient processes.

Investigation of Performance Enhancements for a Liquid-Desiccant Solar Air-Conditioner

Thermally driven liquid-desiccant air-conditioners (LDAC) are a proven but still developing technology. LDACs can use a solar thermal system to reduce the operational cost and environmental impact of the system by reducing the amount of fuel (e.g. natural gas, propane, etc.) used to drive the system. LDACs also have a key benefit of being able to store energy in the form of concentrated desiccant storage. TRNSYS simulations were used to evaluate several different methods of improving the thermal and electrical coefficients of performance (COPt and COPe) and the solar fraction (SF) of a LDAC. The study analyzed a typical June to August cooling season in Toronto, Ontario. Utilizing properly sized, high-efficiency pumps increased the COPe to 3.67, an improvement of 55%. A new design, featuring a heat recovery ventilator on the scavenging-airstream and an energy recovery ventilator on the process-airstream, increased the COPt to 0.58, an improvement of 32%. This also improved the SF slightly to 54%, an increase of 8%. A new TRNSYS TYPE was created to model a stratified desiccant storage tank. Different volumes of desiccant were tested with a range of solar array system sizes. The largest storage tank coupled with the largest solar thermal array showed improvements of 64% in SF, increasing the value to 82%. The COPe was also improved by 17% and the COPt by 9%. When combining the heat recovery systems and the desiccant storage systems, the simulation results showed a 78% increase in COPe and 30% increase in COPt. A 77% improvement in SF and a 17% increase in total cooling rate were also predicted by the simulation. The total thermal energy consumed was 10% lower and the electrical consumption was 34% lower. The amount of non-renewable energy needed from the natural gas boiler was 77% lower. Comparisons were also made between LDACs and vapour-compression (VC) systems. Dependent on set-up, LDACs provided higher latent cooling rates and reduced electrical power consumption. Negatively, a thermal input was required for the LDAC systems but not for the VC systems.

Malta Transformed by Multi-level Governance: More Than Just an Outcome of Europeanisation. Occasional Paper 03/2014

Malta has been transformed in many ways with and by EU Membership. This paper goes beyond the more obvious impacts of ‘Europeanisation’ and instead reviews the implications of an explosion of multi-level governance on doing politics in Malta. While for most of its recent political history, there has been a clawing back of power by the central government – as when the Gozo Civic Council (1960-1973), an early foray into regional government, was “unceremoniously dissolved” in 1973 – this trend was reversed with the setting up of local councils as from 1994, an advisory Malta Council for Economic and Social Development (MCESD) in 2001, and then EU membership in 2004. These events have created a profligacy of decision-making tiers and multiplied the tensions that exist between different levels of governance in this small archipelago state. Malta has never experienced such pluralism before. In fact, since 1966, only two political parties have been represented in the national legislature and, therefore, there has been no division of powers between the executive and the national parliament. This paper reviews the implications of these developments on two hot political issues in 2014: the International Investor Programme (IIP) proposed by the Labour Government in its 2014 Budget; and the location of a Liquid Natural Gas (LNG)-storage vessel inside Marsaxlokk harbour.

A bottomless pit: the costs of Crimea’s annexation by Russia. OSW Commentary No. 143, 29.07.2014

The annexation of Crimea has brought the Russian authorities significant dividends, in particular on the domestic stage: it has resulted in an unprecedented social and political consolidation, and strengthened Vladimir Putin’s position after several years of decline in social support for him. It has provided Russia with strategic benefits, giving it broad access to the Black Sea and the military infrastructure on the peninsula, as well as access to natural gas and crude oil reserves. Russia has also taken over numerous assets (including the tourist infrastructure) previously owned by the Ukrainian state. However, the decision itself concerning Moscow’s annexation of Crimea was taken off the cuff, with no calculation of the costs of integrating it with the Russian legal, political and socio-economic space. Russia took over a region that required subsidies from the Ukrainian budget; moreover, the annexation struck at the most important industry of the Crimean economy – tourism. Crimea’s integration with Russia will be a complex process that entails high costs, financial, organisational and social, including multi-billion dollar investments in the modernisation and development of infrastructure, covering the region’s budget deficit, and paying out social benefits. For reasons of prestige and political significance, Moscow is treating Crimea as a showcase region. Russia is determined to prove that the Crimean incorporation will be beneficial for the region’s economy and will raise people’s living standards. However, the expenses triggered by Crimea’s integration will coincide with a deteriorating economic situation in Russia, aggravated by US and EU sanctions, and this may force Russia to postpone or even give up some of its ambitious investments in the peninsula. Some of the integration costs will have to be borne by other Russian regions, even though they already face serious financial problems that have forced them to reduce their own investment programs. Another issue that has come into question is the fulfilment of the Crimean people’s’ expectations concerning the improvement of their living standards, due to the tourist sector’s problems (small-scale tourist services used to be one of the local people’s main sources of income), the rising costs of maintenance, and finally, restrictions of civil rights after the introduction of the more restrictive Russian legislation.

Gazprom's expansion in the EU - co-operation or domination? OSW Report, April 2008

The energy sector, especially with regard to natural gas trade, is one of the key areas of co-operation between the EU and Russia. However, the character of this co-operation has given rise to increasing doubts both in Brussels and among the EU member states. The questions have emerged whether this co-operation does not make the EU excessively dependent on Russian energy supplies, and whether Gazprom's presence in the EU will not allow Moscow to interfere in the proces of devising the EU energy policy. This report is intended to present the factual base and data necessary to provide accurate answers to the foregoing questions. The first part of the report presents the scope and character of Gazprom's economic presence in the EU member states. The second part shows the presence of the EU investors in Russia. The data presented has been provided by the International Energy Agency, European Commission, the Central Bank of Russia and the Russian Federal State Statistics Service. Some of the data is the result of calculations made by the Centre for Eastern Studies' experts who were basing on the data provided by energy companies, the specialist press and news agencies.

At any price: Russia is embarking on the construction of South Stream. OSW Commentary No. 98, 2012-12-07

Gazprom is determined to continue its efforts to build the South Stream gas pipeline regardless of the slump on the European gas market and the fact that there is sufficient capacity already in the existing transport infrastructure. The official inauguration of the maritime section of South Stream was held on 7 December this year, but the construction itself will commence in 2014. The agreements concluded so far, both intergovernmental and between corporations, are necessary for the launch of the construction of the new pipeline, but still do not guarantee that the project will be completed on time. First of all, some legal problems have yet to be resolved, such as the evaluation of the compliance of the planned actions with the ‘third energy package’ or the fact that ecological surveys required under European law need to be carried out. Secondly, given the present situation on the European gas market and medium-term forecasts, the high cost of implementation of this project and the maintenance expenses of existing pipelines – which are not being used to full capacity – the new project seems to be unfeasible. However, Gazprom’s determination in its efforts to build the pipeline proves that Russia is ready to take a high economic risk to maintain its dominant position on the European gas supply market; it will restrict the possibilities of alternative infrastructural projects being implemented (above all, the EU’s Southern Corridor) and use the construction of new pipelines as an instrument of political pressure on the present transit countries (especially Ukraine).

Ukrainian economy on the verge of recession. OSW Commentary No. 96, 2012-11-21

In the third quarter of 2012, Ukraine’s economy recorded negative growth (-1.3%) for the first time since its 2009 economic crisis. Q4 GDP is projected to suffer a further decline, bringing Ukraine into formal recession. In addition to the worsening macroeconomic indicators, Ukraine is also facing a series of concomitant economic problems: a growing trade deficit, industrial decline, shrinking foreign exchange reserves, and the weakening of the hryvnia. Poor economic growth is expected to result in lower than projected budget revenues, which in turn could lead to the sequestration of the budget in December. The decline evident across the key economic indicators in the second half of 2012 brings to a close a period of relative economic stability and two years of economic growth, which had been seen as a significant personal achievement of President Viktor Yanukovych and the ruling Party of Regions. The health of the Ukrainian economy largely depends on the state of the country’s export- -oriented industries. The current economic forecasts for foreign markets are not very optimistic. It is impossible to determine whether the current economic downturn is likely to be merely temporary or whether it heralds the onset of a prolonged economic crisis. The limited capacity to deal with the growing economic problems may mean that Kiev will need to seek financial support from abroad. This is particularly significant with regard to external debt servicing, since in 2013 Ukraine will need to pay back around 9 billion USD, including over 5.5 billion USD to the International Monetary Fund. In order to overcome the recession and stabilise public finances, the government may be forced to take a series of unpopular measures, including raising the price of natural gas and utilities. These measures have been stipulated by the IMF as a condition of further financial assistance and the disbursement of the 12 billion USD stabilisation loan granted to Ukraine in July 2010. The only alternative for Western loans and economic reforms appears to be financial support from Russia. The price for Moscow’s help might however turn out to be very high, and precipitate a turn in Kiev’s foreign policy towards a gradual re-integration of former Soviet republics under Moscow-led geopolitical projects.

Gazprom’s evolving strategy in a new commercial and political context: how should the EU react? EPC Policy Brief, 27 April 2015

After years of unchallenged commercial domination of a sizeable portion of the EU's gas market, Gazprom is confronted with a statement of objections issued on 22 April by the EU Commission for abusing its dominant market position. The company was already prevented from going ahead with its South Stream project aimed at consolidating Gazprom's grip on Southeast Europe's markets by bypassing Ukraine – due to alleged non-compliance of intergovernmental agreements with the EU regulatory framework. Furthermore, it walked away from negotiations that could have allowed it to access more than 50% of the OPAL pipeline – an onshore branch of the offshore Russian German Nord Stream pipeline –, whilst its attempts to go downstream through the acquisition of European distribution and transmission operators, such as Wingas and DESFA, failed due to current political tensions and the risk of a negative Commission ruling on the operation. Does this mean that the Russian gas behemoth – so often portrayed as the energy arm of the Kremlin – is not so powerful after all? This Policy Brief aims to frame the erosion of Gazprom's power in a wider perspective, analysing its peculiar position at a time of transition, with the global gas business going from a sellers' to a buyers' market, and providing recommendations on how Europe should deal with it. It will be argued that Gazprom – despite still being affected by the Kremlin's political priorities – is moving towards more commercially sound behavior. The EU should profit from this evolution without being tempted by mercantilist options, and rather use the political momentum provided by the energy union to remove barriers to solidarity and to increase competition on the trading platforms.

Validation of the Swiss methane emission inventory by atmospheric observations and inverse modelling

Atmospheric inverse modelling has the potential to provide observation-based estimates of greenhouse gas emissions at the country scale, thereby allowing for an independent validation of national emission inventories. Here, we present a regional-scale inverse modelling study to quantify the emissions of methane (CH₄) from Switzerland, making use of the newly established CarboCount-CH measurement network and a high-resolution Lagrangian transport model. In our reference inversion, prior emissions were taken from the "bottom-up" Swiss Greenhouse Gas Inventory (SGHGI) as published by the Swiss Federal Office for the Environment in 2014 for the year 2012. Overall we estimate national CH₄ emissions to be 196 ± 18 Gg yr⁻¹ for the year 2013 (1σ uncertainty). This result is in close agreement with the recently revised SGHGI estimate of 206 ± 33 Gg yr⁻¹ as reported in 2015 for the year 2012. Results from sensitivity inversions using alternative prior emissions, uncertainty covariance settings, large-scale background mole fractions, two different inverse algorithms (Bayesian and extended Kalman filter), and two different transport models confirm the robustness and independent character of our estimate. According to the latest SGHGI estimate the main CH₄ source categories in Switzerland are agriculture (78 %), waste handling (15 %) and natural gas distribution and combustion (6 %). The spatial distribution and seasonal variability of our posterior emissions suggest an overestimation of agricultural CH₄ emissions by 10 to 20 % in the most recent SGHGI, which is likely due to an overestimation of emissions from manure handling. Urban areas do not appear as emission hotspots in our posterior results, suggesting that leakages from natural gas distribution are only a minor source of CH₄ in Switzerland. This is consistent with rather low emissions of 8.4 Gg yr⁻¹ reported by the SGHGI but inconsistent with the much higher value of 32 Gg yr⁻¹ implied by the EDGARv4.2 inventory for this sector. Increased CH₄ emissions (up to 30 % compared to the prior) were deduced for the north-eastern parts of Switzerland. This feature was common to most sensitivity inversions, which is a strong indicator that it is a real feature and not an artefact of the transport model and the inversion system. However, it was not possible to assign an unambiguous source process to the region. The observations of the CarboCount-CH network provided invaluable and independent information for the validation of the national bottom-up inventory. Similar systems need to be sustained to provide independent monitoring of future climate agreements.