Eficiência energética na fabricação de placas cerãmicas mediante a utilização de óleo térmico

O processo de fabricação de placas cerâmicas consome uma grande quantidade de energia, maioritariamente energia térmica, que se obtém da combustão de gás natural. O aumento do custo deste combustível, assim como a situação económica do presente, faz com que este custo seja crítico para as empresas e pode minar a sua competitividade. O processo de cozedura das placas cerâmicas em fornos de rolos não se destaca precisamente pelo aproveitamento da energia utilizada, visto que aproximadamente 50% perdese através das chaminés de fumos e de arrefecimento do forno. Com o propósito de melhorar o aproveitamento da energia consumida durante a operação de cozedura instalaramse, nas chaminés de um forno, dois permutadores de calor, nos quais os gases provenientes do forno cedem o seu calor sensível a um óleo térmico, que posteriormente o transfere, através de outros dois permutadores, aos gases de secagem nas condutas de recirculação de um secador vertical. Neste trabalho apresenta-se uma instalação industrial experimental, na qual os resultados obtidos de economia energética se situam num valor médio de 650 kW, dependendo das condições de funcionamento e dos materiais processados

Setting conclitions, Petrology ancl Geochemistry of calc-alkaline rhyolites, stephanian-permian, in the iberian chains

[Resumen] Se exponen los caracteres del emplazamiento, la composición petrológica y geoquímica de unos sills riolíticos que, con afinidad calco-alcalina, se emplazaron, bajo un ambiente sin-colisional, en diversos sectores de la Cadena Ibérica. Estas riolitas representan un origen crustal, con baja tasa de fusión, previo a un magmatismo calco-alcalino de origen subcrustal.[Abstract] The setting characters, the petrological and geochemical composition are exposed for sorne rhyolitic sills, with calc-alkaline affinity, which were set, in a syncollisional environment, in several areas of the Iberian Chains. These rhyolites represent a crustal origin, with a low degree of fussion, previous to a calc-alkaline magmatism of subcrustal origino

Reduction of CO2-emissions in ceramic tiles manufacture by combining energy-saving measures

Ceramic tile manufacture requires a great quantity of energy, mainly in the form of heat. The heat is principally used in the kilns and dryers, and it is obtained by natural gas combustion. The increasing cost of natural gas, as well as the application of a new gas tax, the new legislation in regard to emissions trading, and the difficult current economic situation have driven the ceramic tile sector to implement energy-saving actions in the production process with the twofold aim of reducing energy costs and abating carbon dioxide emissions. One such course of action is the European project REDUCER, funded by the European Commission and led by Azulev S.A.U., in which the Instituto de Tecnología Cerámica (ITC) also participates. This project seeks to implement energy-saving actions in company kilns and dryers in order to lower natural gas consumption and reduce carbon dioxide emissions in the tile manufacturing process. One of the saving actions envisaged is the installation of a system of waste heat recovery from one of the company kilns to the tile body dryers. This new waste heat recovery system is to be added to and will complement the already existing system at the company, thus achieving maximum heat recovery from the kiln stacks. The recovered heat will go entirely to the green tile body dryers, thus reducing natural gas consumption in the dryers. The designed installation seeks to recover 600 kW heat from the stacks of one of the kilns, entailing a natural gas saving of more than 120 k€/year and suppressing the emission into the atmosphere of 720 tons of CO2/year, savings that are to be added to those attained with other energy-saving measures. This paper describes the energy-saving actions implemented at the company, as well as the resulting energy savings

Brasil x Espanha: consumo de energia térmica e emissões de CO2 envolvidos na fabricação de revestimentos cerâmicos

A demanda de energia térmica da indústria de revestimentos cerâmicos é bastante elevada, sendo atendida quase por completo pela combustão do gás natural. Os gastos com geração de energia térmica representam uma grande parte do custo de produção de revestimentos cerâmicos, e as emissões de CO2 resultantes desta atividade industrial são muito expressivas. Neste sentido, o aumento da eficiência térmica nos processos produtivos conhecidos atualmente deve ser buscado constantemente com o objetivo de reduzir o custo de fabricação e as emissões de CO2. Para isso, é necessário dispor de uma base de dados de consumos energéticos e emissões de CO2, a fim de conhecer a situação atual do setor e as possibilidades de aumentar a eficiência energética do processo. Dessa forma, o presente trabalho foi realizado com o objetivo de levantar dados baseados em medições diretas em equipamentos industriais consumidores de gás natural, no Brasil e na Espanha, utilizando a mesma metodologia. Foram visitadas 65 empresas e analisados 130 equipamentos, sendo possível estabelecer comparações entre o consumo de diversas tipologias de produtos, etapas do processo produtivo, distintas rotas de processamento, equipamentos com características construtivas diferenciadas, dentre outros. As informações obtidas constituem um inédito banco de dados que representa a real situação dos setores de revestimentos cerâmicos do Brasil e da Espanha, com respeito ao consumo energético e às emissões de CO2

Preliminary comparison of magmatic manifestations, calc-alkaline affinity and stephanian-permian age, in the Iberian Chain

[Resumen] En este trabajo se estudian, de forma sintética y actualizada, las manifestaciones (hipovolcánicas y volcanoclásticas) calco-alcalinas que, con carácter epizonal, pluriepisódico y edad Stephaniense-Pérmico, afloran en la Cadena Ibérica. El estudio del magmatismo en la cuenca de Sauquillo de Alcázar (Soria) permite identificar la geometría y la modalidad de este magmatismo con mayor precisi6n, respecto a lo obtenido en los cuatro afloramientos volcano-clásticos seleccionados. Los resultados obtenidos facilitan realizar consideraciones sobre el estudio espacio-temporal de este magmatismo..[Abstract] A synthetic and actualized study of several magmatic calc-alkaline manifestations of Stephanian-Permian age, of the Iberian Chain, is proposed in this papero The Sauquillo de Alcázar (Soria) outcrop allows a more complete study (with drilling logs and a surface profile) giving improved spacetime information on the geometry and evolution of this magmatism. Four pyroclastic outcrops are integrated in this compariso

Introducing the Coarse-Scattering Multigroup Method and Fine-Tuning the Finite-Element with Discontiguous-Support Multigroup Method for Time-Dependent Neutron Transport

The purpose of this research is to reduce the runtime and improve the accuracy of deterministic neutron transport simulations. Here, we introduce the coarse-scattering (CS) method, and prove its ability to reduce the computational time required to model scattering in multigroup (MG) simulations. We applied the CS method to a slab-geometry criticality simulation and showed that it was able to reduce the overall runtime of the simulation by almost a factor of four. Furthermore, we proved that the coarse-scattering method can conserve particle balance as long as the CS scattering spectrum and CS fission spectrum are recomputed in the last iteration. In this study, we also showed that finite-element with discontiguous-support (FEDS) method and the multigroup (MG) method have certain advantages and disadvantages for simulating time-of-flight problems. FEDS is inherently able to model cross sections more accurately, while MG inherently is able to model neutron speeds more accurately. We compared a wide variety of FEDS energy discretizations, and determined their performance for a single-material and a multi-material time-of-flight simulation. We found that either using FEDS energy discretizations with large energy penalties or FEDS energy discretizations with a small number of elements per coarse group performed best for time-of-flight sim-ulations. The FEDS energy discretizations that used energy penalties were usually more accurate than the MG simulations for the single-material and the multi-material time-of-flight problems, for various detector distances and number of time bins. Also, the FEDS energy discretization that used exactly two FEDS elements in each coarse group was competitive with MG for the single-material time-of-flight problem and usually more accurate than MG for the multi-material time-of-flight problem

Comparing Contiguous and Discontiguous Energy Grids and Propogating Uncertainties for Radiation Transport Finite Element Methods

The purpose of this study is to quantitatively compare the accuracy of radiation transport finite element methods which use a contiguous support to those which use a discontiguous support of the energy domain. The finite-element-with-discontiguous-support method (FEDS) is a generalized finite element framework for discretizing the energy domain of radiation transport simulations. FEDS first decomposes the energy domain into coarse groups and then further partitions the coarse groups into discontiguous energy elements within each coarse group. A minimization problem is solved in order to optimally cluster portions of the energy domain into FEDS elements. This document presents a procedure for propagating uncertainties for FEDS, and afterwards presents four benchmark problems that test the efficacy of FEDS, compared to Multigroup, for different radiation transport problems. The results from these benchmark problems suggest that we are accurately generating FEDS cross sections, correctly propating uncertainties from the nuclear data libraries, and that FEDS converges faster than Multigroup to an energy-resolved solution. The absolute error in the verification problems were 6 x 10^-8 and 5 x 10^-8, respectively, and the absolute error in the validation problems were 2 x 10^-4, and 4 x 10^-3, respectively

Geochemical exploration in the Montseny Mountains (NE Spain)

A five year program of systematic multi-element geochemical exploration of the Catalonian Coastal Ranges has been initiated by the Geological Survey of Autonomic Government of Catalonia (Generalitat de Catalunya) and the Department of Geological and Geophysical Exploration (University of Barcelona). This paper reports the first stage results of this regional survey, covering an area of 530 km2 in the Montseny Mountains, NE of Barcelona (Spain). Stream sediments for metals and stream waters for fluoride were chosen because of the regional characteristics. Four target areas for future tactic survey were recognized after the prospect. The most important is a 40 km* zone in the Canoves-Vilamajor area, with high base metal values accompanied by Cd, Ni, Co, As and Sb anomalie

The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans

Contamination des milieux aquatiques Camarguais par les résidus de produits phyto sanitaires

Les auteurs font état des résultats qu’ils ont obtenu au terme de deux années de recherches sur la contamination des milieux aquatiques cam arguais par les résidus de produits phytosanitaires. En Camargue, les techniques culturales employées, notam ment en riziculture : irrigation intensive et extensive, lutte chimique contre les parasites, menacent de pollution l’ensemble des milieux aquatiques et plus particulièrement les étangs de la Réserve Naturelle Zoologique et Rotanique. Les polluants sont d’origine rhodanienne ou proviennent des traitements agricoles, herbicides et insecticides. L’étude concernant les herbicides est délicate à mener et les résultats obtenus jusqu’à présent sont trop fragmentaires pour pouvoir être interprétés. Des résultats plus complets concernant les insecticides montrent que la contamination de l’eau est encore très faible, mais que l’accumulation des résidus organochlorés aux différents échelons trophiques des biocœnoses présente un réel danger. Les pesticides les plus fréquemment rencontrés sont alpha HCH (d’origine rhodanienne), gamma HCH (d’origine rhodanienne et agricole). La présence à des doses décelables de DDT est moins courante. D’autres résidus ne sont soupçonnés dans l’eau que du fait de leur présence dans les tissus animaux (dieldrine). D’autres enfin ne sont décelés qu’en période de traitement des cultures (les organophosphorés et notamment le parathion), ou à la faveur de circonstances particulières (polychlorocamphane) . Les polychlorobiphényles présents dans le milieu posent un problème. Leur origine est probablement mixte (Rhône et spé cialités commerciales de pesticides agricoles où ils servent d’adjuvant). Ces organochlorés très stables sont accumulés à des taux relativement importants aussi bien dans les sédiments que dans les végétaux et les animaux aquatiques et présentent un réel danger pour la conservation des milieux naturels. La conciliation de l’agriculture et de la conservatoin de la nature en Camargue est subordonnée à deux conditions : le rejet au Rhône de toutes les eaux de drainage des cultures jusqu’à présent déversées dans le Vaccarès et la recherche de pratiques culturales moins polluantes que celles actuellement employées.Results are given of a two year study on the pollution by pesticide-residues of the aquatic environment in the Camargue. The agricultural techniques employed, notably in rice-growing (intensive and extensive irrigation, chemical control of pests) threaten the whole aquatic environment in the Camargue with pollution, particularly the lakes situated in the « Réserve Naturelie Zoologique et Botanique ». These pollutants originate from the Rhône river and from agricultural treatments using herbicides and insecticides. Herbicide studies have proved difficult to conduct and results obtained to date are too fragmentary to allow a clear interpretation. More detailed results on insecticides show that water pollu tion is still very low but that the accumulation of organo- chlorides at the different trophic levels of the ecosystem presents a real threat. The pesticides most frequently recorded are alpha HCH (BHC) (Rhone origin) and gamma HCH (Rhone and agricultural origin). Detectable doses of DDT are less frequently recorded. Other residues are only suspected in water because of their presence in animal tissues (dieldrin). Lastly, others are only revealed during the period when crops are treated (organophosphates and espe cially parathion) or as a result of very particular circumstances (polychlorocamphene) . The presence of polychlorobiphenyls in the environment raises a special problem. They probably have a mixed origin (Rhone and commercial types of agricultural pesticides where they serve as an adjuvant). These very stable organochlorides are accumulated at relatively high rates in sediments as well as in aquatic plants and animals, and present a real danger to the conservation of natural habitats. The conciliation of agriculture and nature conservation in the Camargue is dependent on two conditions : return into the Rhone of all run-off water from crops, at present discharged into the « Etang du Vaccarès », and research into cultural methods which produce less pollution than those in current use