983 resultados para renewable resources
Resumo:
Coal, natural gas and petroleum-based liquid fuels are still the most widely used energy sources in modern society. The current scenario contrasts with the foreseen shortage of petroleum that was spread out in the beginning of the XXI century, when the concept of "energy security" emerged as an urgent agenda to ensure a good balance between energy supply and demand. Much beyond protecting refineries and oil ducts from terrorist attacks, these issues soon developed to a portfolio of measures related to process sustainability, involving at least three fundamental dimensions: (a) the need for technological breakthroughs to improve energy production worldwide; (b) the improvement of energy efficiency in all sectors of modern society; and (c) the increase of the social perception that education is a key-word towards a better use of our energy resources. Together with these technological, economic or social issues, "energy security" is also strongly influenced by environmental issues involving greenhouse gas emissions, loss of biodiversity in environmentally sensitive areas, pollution and poor solid waste management. For these and other reasons, the implementation of more sustainable practices in our currently available industrial facilities and the search for alternative energy sources that could partly replace the fossil fuels became a major priority throughout the world. Regarding fossil fuels, the main technological bottlenecks are related to the exploitation of less accessible petroleum resources such as those in the pre-salt layer, ranging from the proper characterization of these deep-water oil reservoirs, the development of lighter and more efficient equipment for both exploration and exploitation, the optimization of the drilling techniques, the achievement of further improvements in production yields and the establishment of specialized training programs for the technical staff. The production of natural gas from shale is also emerging in several countries but its production in large scale has several problems ranging from the unavoidable environmental impact of shale mining as well as to the bad consequences of its large scale exploitation in the past. The large scale use of coal has similar environmental problems, which are aggravated by difficulties in its proper characterization. Also, the mitigation of harmful gases and particulate matter that are released as a result of combustion is still depending on the development of new gas cleaning technologies including more efficient catalysts to improve its emission profile. On the other hand, biofuels are still struggling to fulfill their role in reducing our high dependence on fossil fuels. Fatty acid alkyl esters (biodiesel) from vegetable oils and ethanol from cane sucrose and corn starch are mature technologies whose market share is partially limited by the availability of their raw materials. For this reason, there has been a great effort to develop "second-generation" technologies to produce methanol, ethanol, butanol, biodiesel, biogas (methane), bio-oils, syngas and synthetic fuels from lower grade renewable feedstocks such as lignocellulosic materials whose consumption would not interfere with the rather sensitive issues of food security. Advanced fermentation processes are envisaged as "third generation" technologies and these are primarily linked to the use of algae feedstocks as well as other organisms that could produce biofuels or simply provide microbial biomass for the processes listed above. Due to the complexity and cost of their production chain, "third generation" technologies usually aim at high value added biofuels such as biojet fuel, biohydrogen and hydrocarbons with a fuel performance similar to diesel or gasoline, situations in which the use of genetically modified organisms is usually required. In general, the main challenges in this field could be summarized as follows: (a) the need for prospecting alternative sources of biomass that are not linked to the food chain; (b) the intensive use of green chemistry principles in our current industrial activities; (c) the development of mature technologies for the production of second and third generation biofuels; (d) the development of safe bioprocesses that are based on environmentally benign microorganisms; (e) the scale-up of potential technologies to a suitable demonstration scale; and (f) the full understanding of the technological and environmental implications of the food vs. fuel debate. On the basis of these, the main objective of this article is to stimulate the discussion and help the decision making regarding "energy security" issues and their challenges for modern society, in such a way to encourage the participation of the Brazilian Chemistry community in the design of a road map for a safer, sustainable and prosper future for our nation.
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Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS). Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 ºC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.
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Diplomityössä on selvitetty Etelä-Karjalan maakunnan energian käyttöä nyt ja tulevaisuudessa. Tavoitteena on selvittää eri energialähteiden hankintavaihtoehtoja, sekä eri energialähteiden käytön kehittymissuunnat seuraavan 10 - 20 vuoden kuluessa. Diplomityö on tehty Etelä-Karjalan liiton toimeksiannosta ja sitä tullaan käyttämään taustaselvityksenä maakuntakaavan laadinnassa sekä maakunnan aluevarauksia määriteltäessä. Tarkoituksena on arvioida miten energiahuollon rakenne tulee muuttumaan tulevaisuudessa ja mikä merkitys tulevaisuuden energiaratkaisuilla on alueiden käyttöön ja aluerakenteeseen liittyen. Etelä-Karjala on osa Euroopan suurinta metsäteollisuuskeskittymää ja maakunta on Suomen suurimpia teollisuuden energian- ja sähkönkäyttäjiä. Etelä-Karjalan vahva metsäteollisuus ja sen käyttämät puupolttoaineet sekä sijainti Venäjän maakaasuvarojen läheisyydessä ja kattava maakaasuverkko vaikuttavat merkittävästi maakunnan energiataseeseen. Vuonna 2007 Etelä-Karjalan primäärienergiankäyttö oli 24,3 TWh, tästä uusiutuvien energialähteiden osuus oli 68 % ja fossiilisten energialähteiden osuus 22 %. Etelä-Karjalan energiatalouden tulevaisuuteen vaikuttaa merkittävästi maakunnan metsäteollisuuden tulevaisuus. Tiukentuvan energia- ja ilmastopolitiikan ja ympäristömääräysten myötä maakunnan energiatehokkuutta on parannettava kaikilla sektoreilla. Maakunnan energiankulutusta voidaan vähentää tehostamalla energiantuotantoa, tiivistämällä yhdyskuntarakennetta ja lisäämällä bioenergian käyttöä energiantuotannossa. Etelä-Karjalassa on myös potentiaalia lisätä vaihtoehtoisten energialähteiden osuutta maakunnan energiatalouden tulevaisuudessa.
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The subject being analyzed of this Master’s Thesis is a development of a service that is used to define a current location of a mobile device. The service utilized data that is obtained from own GPS receiver in some possible cases and as well data from mobile devices which can be afforded for the current environment for acquisition of more precise position of the device. The computation environment is based on context of a mobile device. The service is implemented as an application for communicator series Nokia N8XX. The Master’s Thesis presents theoretical concept of the method and its practical implementation, architecture of the application, requirements and describes a process of its functionality. Also users’ work with application is presented and recommendations for possible future improvements are made.
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Most Finnish periodical magazines have a website, often an online service. The objective of this thesis is to understand the magazines’ resources and capabilities and match them with online strategies’ goals and objectives. The thesis’ theoretical part focuses on explaining and classifying resources, capabilities, goals and objectives, and applying everything into Finnish magazine publishing context. In the empirical part, there is a comparative case study of four magazines. The findings indicate that with cooperating, advertising and community hosting capabilities magazines may utilize their human, brand, content and customer base resources. The resources can be further addressed to reach profitability, customer-centricity and brand congruency goals.
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Kirjallisuusarvostelu
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Tämän diplomityön tavoitteena oli vertailla paikallisia energiantuotantovaihtoehtoja eri-tyisesti lämmöntuotantoon painottuen. Tarkastelu sovitettiin uuden matalaenergiarakentamista vastaavan kerrostaloasuinalueen tarpeisiin. Näkökulmana olivat sekä taloudellisuus että hiilidioksidipäästöt. Yksityiskohtaisemman tarkastelun kohteena olivat maalämpö, alueellinen biolämpölaitos sekö alueellinen pien-CHP-laitos. Perusvaihtoehtona tutkittiin kaukolämpöä. Kaikkiin vaihtoehtoihin kuului myös kapasiteetiltaan rajoitettu jäähdytys. Tulosten mukaan kokonaistaloudellisin vaihtoehto oli maalämpö yhdistettynä kaukolämpöön. Tässä vaihtoehdossa peruslämpö tuotetaan maalämmöllä, mutta huippu-lämpöön sekä käyttöveden lämmitykseen käytetään kaukolämpöä. Ratkaisulla saadaan aikaan myös päästövähennyksiä kaukolämpöön verrattuna. Tulosten mukaan pienimmät päästöt olivat pien-CHP-biovoimalaitoksella. Toisaalta nykyisillä sähkön myyntihinnoilla pienimuotoinen yhdistetty sähkön ja lämmön tuotanto ei pysty kilpailemaan kustannusrakenteensa puolesta muiden tutkittujen vaihtoehtojen kanssa.
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The thesis explores global and national-level issues related to the development of markets for biomass for energy. The thesis consists of five separate papers and provides insights on selected issues. The aim of Paper I was to identify methodological and statistical challenges in assessing international solid and liquid biofuels trade and provide an overview of the Finnish situation with respect to the status of international solid and liquid biofuels trade. We found that, for the Finnish case, it is possible to qualify direct and indirect trade volumes of biofuels. The study showed that indirect trade of biofuels has a highly significant role in Finland and may be a significant sector also in global biofuels trade. The purpose of Paper II was to provide a quantified insight into Finnish prospects for meeting the national 2020 renewable energy targets and concurrently becoming a largescale producer of forest-biomass-based second-generation biofuels for feeding increasing demand in European markets. We found that Finland has good opportunities to realise a scenario to meet 2020 renewable energy targets and for large-scale production of wood-based biofuels. The potential net export of transport biofuels from Finland in 2020 would correspond to 2–3% of European demand. Paper III summarises the global status of international solid and liquid biofuels trade as illuminated by several separate sources. International trade of biofuels was estimated at nearly 1 EJ for 2006. Indirect trade of biofuels through trading of industrial roundwood and material by-products comprises the largest proportion of the trading, with a share of about two thirds. The purpose of Paper IV was to outline a comprehensive picture of the coverage of various certification schemes and sustainability principles relating to the entire value-added chain of biomass and bioenergy. Regardless of the intensive work that has been done in the field of sustainability schemes and principles concerning use of biomass for energy, weaknesses still exist. The objective of Paper V was to clarify the alternative scenarios for the international biomass market until 2020 and identify the underlying steps needed toward a wellfunctioning and sustainable market for biomass for energy purposes. An overall conclusion drawn from this analysis concerns the enormous opportunities related to the utilisation of biomass for energy in the coming decades.
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Diesel fuel is used widely in Brazil and worldwide. On the other hand, the growing environmental awareness leads to a greater demand for renewable energy resources. Thus, this study aimed to evaluate the use of different blends of soybean (Glycine max) methyl biodiesel and diesel in an ignition compression engine with direct injection fuel. The tests were performed on an electric eddy current dynamometer, using the blends B10, B50 and B100, with 10; 50 e 100% of biodiesel, respectively, in comparison to the commercial diesel B5, with 5% of biodiesel added to the fossil diesel. The engine performance was analyzed trough the tractor power take off (PTO) for each fuel, and the best results obtained for the power and the specific fuel consumption, respectively, were: B5 (44.62 kW; 234.87 g kW-1 h-1); B10 (44.73 kW; 233.78 g kW-1 h-1); B50 (44.11 kW; 250.40 g kW-1 h-1) e B100 (43.40 kW; 263.63 g kW-1 h-1). The best performance occurred with the use of B5 and B10 fuel, without significant differences between these blends. The B100 fuel showed significant differences compared to the other fuels.
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The consideration of the streamflow seasonality has a high potential to improve the water use. In order to give subsidies to the optimization of water use, it was evaluated the impact of the change of reference annual streamflow by the monthly streamflows in the potential water use throughout the hydrography of Paracatu sub-Basin. It was evaluated the impact on Q7,10 (lowest average streamflow during a 7-day period with an average recurrence of 10 years) and on Q95 (permanent flow present 95% of the time). The use of monthly streamflow to substitute the annual streamflow had a high potential of improvement of water resources use in the sub-Basin studied. The use of monthly Q 7,10 in substitution of annual Q 7,10 increases the potential water use that vary from about 10% in the months of lower water availability to values exceeding 200% in the months with higher availability of surface water resources. The use of monthly Q95 in substitution of the annual Q95 implies in changes oscillating from reduction of 37% in months of higher water restriction to values exceeding 100% in the months of higher availability, so the use of monthly Q95 instead of the annual Q95 enables the more rational and safe use of water resources.
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The development of new technologies to supplement fossil resources has led to a growing interest in the utilization of alternative routes. Biomass is a rich renewable feedstock for producing fine chemicals, polymers, and a variety of commodities replacing petroleumderived chemicals. Transformation of biomass into diverse valuable chemicals is the key concept of a biorefinery. Catalytic conversion of biomass, which reduces the use of toxic chemicals is one of the important approaches to improve the profitability of biorefineries. Utilization of gold catalysts allows conducting reactions under environmentally-friendly conditions, with a high catalytic activity and selectivity. Gold-catalyzed valorization of several biomass-derived compounds as an alternative approach to the existing technologies was studied in this work. Isomerization of linoleic acid via double bond migration towards biologically active conjugated linoleic acid isomers (CLA) was investigated. The activity and selectivity of various gold catalysts towards cis-9,trans-11-CLA and trans-10,cis-12-CLA were investigated in a semi-batch reactor, showing that the yield of the desired products varied, depending on the catalyst support. The structure sensitivity in the selective oxidation of arabinose was demonstrated using a series of gold catalysts with different Au cluster sizes in a shaker reactor operating in a semibatch mode. The gas-phase selective oxidation of ethanol was studied and the influence of the catalyst support on the catalytic performance was investigated. The selective oxidation of the lignan hydroxymatairesinol (HMR), extracted from the Norway spruce (Picea abies) knots, to the lignan oxomatairesinol (oxoMAT) was extensively investigated. The influence of the reaction conditions and catalyst properties on the yield of oxoMAT was evaluated. In particular, the structure sensitivity of the reaction was demonstrated. The catalyst deactivation and regeneration procedures were studied. The reaction kinetics and mechanism were advanced.
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Thirty heads with the neck segment of Caiman latirostris were used. The animals were provided from a creation center called Mister Caiman, under the authorization of the Brazilian Institute of Environment and Renewable Natural Resources (Ibama). Animals were sacrificed according to the slaughtering routine of the abattoir, and the heads were sectioned at the level of the third cervical vertebra. The arterial system was washed with cold saline solution, with drainage through jugular veins. Subsequently, the system was filled with red colored latex injection. Pieces were than fixed in 20% formaldehyde, for seven days. The brains were removed, with a spinal cord segment, the duramater removed and the arteries dissected. At the level of the hypophysis, the internal carotid artery gave off a rostral branch, and a short caudal branch, continuing, naturally, as the caudal cerebral artery. This artery projected laterodorsalwards and, as it overpassed the optic tract, gave off its I (the first) central branch. Penetrated in the cerebral transverse fissure, emitting the diencephalic artery and next its II (second) central branch. Still inside the fissure, originated occipital hemispheric branches and a pineal branch. Emerged from the cerebral transverse fissure, over the occipital pole of the cerebral hemisphere. Projected rostralwards, sagital to the cerebral longitudinal fissure, as interhemispheric artery. This artery gave off medial and convex hemispheric branches to the respective surfaces of the cerebral hemispheres, anastomosed with its contralateral homologous, forming the common ethmoidal artery. This artery entered the fissure between the olfactory peduncles, emerging ventrally and dividing into ethmoidal arteries, right and left, which progressed towards the nasal cavities, vascularizing them. The territory of the caudal cerebral artery included the most caudal area of the base of the cerebral hemisphere, its convex surface, the olfactory peduncles and bulbs, the choroid plexuses and the diencephalus with its parietal organs.
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The iron ore pelletizing process consumes high amounts of energy, including nonrenewable sources, such as natural gas. Due to fossil fuels scarcity and increasing concerns regarding sustainability and global warming, at least partial substitution by renewable energy seems inevitable. Gasification projects are being successfully developed in Northern Europe, and large-scale circulating fluidized bed biomass gasifiers have been commissioned in e.g. Finland. As Brazil has abundant biomass resources, biomass gasification is a promising technology in the near future. Biomasses can be converted into product gas through gasification. This work compares different technologies, e.g. air, oxygen and steam gasification, focusing on the use of the product gas in the indurating machine. The use of biosynthetic natural gas is also evaluated. Main parameters utilized to assess the suitability of product gas were adiabatic flame temperature and volumetric flow rate. It was found that low energy content product gas could be utilized in the traveling grate, but it would require burner’s to be changed. On the other hand, bio-SGN could be utilized without any adaptions. Economical assessment showed that all gasification plants are feasible for sizes greater than 60 MW. Bio-SNG production is still more expensive than natural gas in any case.
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RENSOL (Regional Energy Solutions) project deals with the use of energy efficiency and renewable energy solutions in Kaliningrad Oblast to tackle climate change. Overall objective of the RENSOL work package 1 is to build awareness and knowledge on solutions for energy efficient buildings and street lightning applications. The project report describes available solutions to improve housing energy efficiency.