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Aplicação de biossorventes no tratamento de rejeitos radioativos líquidos / Application of biosorbents in treatment of the radioactive liquid wasteRafael Vicente de Padua Ferreira 20 February 2014 (has links)
Rejeitos radioativos líquidos contendo compostos orgânicos precisam de atenção especial, porque os processos de tratamento disponíveis são caros e difíceis de serem gerenciados. A biossorção é uma potencial técnica de tratamento que tem sido estudada em rejeitos simulados. O termo biossorção é utilizado para descrever a remoção de metais, metalóides e/ou radionuclídeos por um material de origem biológica independentemente de sua atividade metabólica. Dentre as potenciais biomassas, os resíduos agrícolas apresentam características muito atraentes, pois possibilitam a remoção dos radionuclídeos presentes no rejeito utilizando um biossorvente de baixo custo. O objetivo deste estudo foi avaliar o uso potencial de diferentes biomassas originadas de produtos ou resíduos agrícolas (fibra de coco, casca de café e casca de arroz) no tratamento de rejeitos radioativos líquidos orgânicos reais. Foram realizados experimentos com essas biomassas incluindo i) Preparação, ativação e caracterização das biomassas; ii) Realização dos ensaios de biossorção e iii) Avaliação do produto da imobilização de biomassas em cimento. As biomassas foram testadas nas formas brutas e ativadas. A ativação foi realizada com soluções diluídas de HNO3 e NaOH. Os ensaios de biossorção foram realizados em frascos de polietileno, nos quais foram adicionados 10 mL do rejeito radioativo ou diluições do rejeito em água deionizada com o mesmo pH e 2 % da biomassa (m/v). No final do experimento, a biomassa foi separada por filtração e a concentração dos radioisótopos remanescente no filtrado foi determinada por ICP-OES e espectrometria gama. O rejeito estudado contém urânio natural (U (total)), amerício-241 e césio-137. Os tempos de contato adotados foram 30 min, 1, 2 e 4 horas e as concentrações estudadas variaram entre 10% e 100%. Os resultados foram avaliados por meio da capacidade máxima de sorção experimental e modelos ternários de isotermas e cinética. As maiores capacidades de sorção foram observadas com casca de café bruta, com valores aproximados de 2 mg/g de U (total), 40 x10-6 mg/g de Am-241 e 50 x10-9 mg/g de Cs-137 e, também, com fibra de coco ativada, com valores de 2 mg/g de U (total), 70 x10-6 mg/g de Am-241 e 40 x10-9 mg/g de Cs-137. As propriedades avaliadas na determinação da qualidade do produto de imobilização foram água livre, resistência mecânica, trabalhabilidade e tempo de pega. Os melhores produtos de imobilização para estas biomassas foram obtidos com uma relação água/cimento de 0,30, contendo 5%, 10% e 15% de casca café bruto, fibra de coco ativada e casca de café ativado, respectivamente. Estes resultados sugerem que a biossorção com casca de café bruta e fibra de coco sob a forma ativada podem ser aplicadas no tratamento de rejeitos radioativos líquidos orgânicos contendo urânio, amerício-241 e césio-137. / Radioactive liquid waste containing organic compounds need special attention, because the treatment processes available are expensive and difficult to manage. The biosorption is a potential treatment technique that has been studied in simulated wastes. The biosorption term is used to describe the removal of metals, non-metals and/or radionuclides by a material from a biological source, regardless of its metabolic activity. Among the potential biomass, agricultural residues have very attractive features, as they allow for the removal of radionuclides present in the waste using a low cost biosorbent. The aim of this study was to evaluate the potential use of different biomass originating from agricultural products (coconut fiber, coffee husk and rice husk) in the treatment of real radioactive liquid organic waste. Experiments with these biomasses were made including i) Preparation, activation and characterization of biomasses; ii) Conducting biosorption assays; and iii) Evaluation of the product of immobilization of biomasses in cement. The biomasses were tested in raw and activated forms. The activation was carried out with diluted HNO3 and NaOH solutions. Biosorption assays were performed in polyethylene bottles, in which were added 10 mL of radioactive waste or waste dilutions in deionized water with the same pH and 2% of the biomass (w/v). At the end of the experiment, the biomass was separated by filtration and the remaining concentration of radioisotopes in the filtrate was determined by ICP-OES and gamma spectrometry. The studied waste contains natural uranium, americium-241 and cesium-137. The adopted contact times were 30 min, 1, 2 and 4 hours and the concentrations tested ranged between 10% and 100%. The results were evaluated by maximum experimental sorption capacity and isotherm and kinetics ternary models. The highest sorption capacity was observed with raw coffee husk, with approximate values of 2 mg/g of U (total), 40 x10-6 mg/g of Am-241 and 50 x10-9 mg/g of Cs-137 and, also, with activated coconut fiber, with values of 2 mg/g of U (total), 70 x10-6 mg/g of Am-241 and 40 x10-9 mg/g of Cs-137. The properties evaluated to determine the quality of the immobilization product were free water, mechanical strength, workability and setting time. The best immobilization products for these biomasses were obtained with a water/cement ratio of 0.30, containing 5%, 10% and 15% of raw coffee husk, activated coconut fiber and activated raw coffee husk, respectively. These results suggest that biosorption with raw coffee husk and activated coconut fiber can be applied in the treatment of radioactive liquid organic wastes containing uranium, americium-241 and cesium-137.
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An electrothermal fluidized-bed carbon-particle plasma reactor for hazardous waste treatment /Steinbach, Paul B., January 1996 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
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An electrothermal fluidized-bed carbon-particle plasma reactor for hazardous waste treatmentSteinbach, Paul B., January 1996 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
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EFFECTS OF SOLIDS RETENTION TIME ON THE TREATMENT OF SYNTHETIC WASTEWATER USING A MEMBRANE BIOREACTORMACOMBER, JEFF RAYMOND 11 October 2001 (has links)
No description available.
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Nevyriausybinių aplinkosauginių organizacijų vaidmuo atliekų tvarkyme / The role of non-governmental environment control organizations in waste treatmentLastauskienė, Monika 22 January 2009 (has links)
Šiame magistro baigiamajame darbe autorė analizuoja nevyriausybines organizacijas, kaip vieną iš institucijų įtakojančių atliekų tvarkymo sistemą. Šio darbo tikslas yra atskleisti nevyriausybinių aplinkosauginių organizacijų vaidmenį atliekų tvarkyme. Tyrimas pradedamas atliekų tvarkymo sistemos analize, kuri atskleidžia atliekų tvarkymo principus, atskirų atliekų srautų tvarkymo ypatumus bei atliekų tvarkymo kontrolės aspektus. Antrajame skyriuje nagrinėjamas nevyriausybinių organizacijų sektorius. Atskleidžiama nevyriausybinių organizacijų apibrėžimo problematika, analizuojama nevyriausybinių organizacijų veikla išskiriant veiklos apribojimų ir lengvatų aspektus bei aptariami nevyriausybinių organizacijų veiklą reglamentuojantys teisės aktai. Trečias šio magistro baigiamojo darbo skyrius yra skirtas nevyriausybinių aplinkosauginių organizacijų analizei: atskleidžiama nevyriausybinių aplinkosauginių organizacijų sisteminės duomenų bazės nebuvimo problema, įvertinama nevyriausybinių aplinkosauginių organizacijų veikla atliekų tvarkymo srityje, pateikiami veiklos pavyzdžiai, analizuojamos visuomenės turimos žinios apie nevyriausybines aplinkosaugines organizacijas ir jų atliekamą veiklą. Apibendrinant išnagrinėtą teorinę medžiagą ir gautus tyrimo rezultatus pateikiamos išvados bei rekomendacijos ir pasiūlymai. / In this final MA work author analyzes non-governmental organizations as one of these institutions that have influence on the waste treatment system. The aim of this work is to reveal the role of non-governmental environment control organizations in waste treatment. The research starts with analysis of waste treatment system which discloses the principles of waste treatment, peculiarities of separate waste flow treatment, and aspects of waste treatment control. The second part of the work analyzes sectors of non-governmental organizations. Problematic aspects of defining non-governmental organizations are presented, practice of non-governmental organizations is analyzed by singling out aspects of practice limitations and concessions, and legal acts that specify the practice of non-governmental organizations. The third part of this work focuses on the analysis of non-governmental environment control organizations: this part reveals the problem of lack of systemic non-governmental environment control organizations data base, evaluates the practice of non-governmental environment control organizations in the area of waste treatment, presents examples of the practice, analyzes the community's knowledge about non-governmental environment control organizations and their activities. Having analyzed theoretical material and results of the survey, certain conclusions, recommendations, and suggestions are presented.
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Syntheses, characterisation and applications of ionic liquids to recover materials from WEEEFaivre, Romain January 2010 (has links)
The recycling of materials from waste electrical and electronic equipment (WEEE) is of great concern today, as increasing public awareness and the implementation of recent legislations have created a situation where industries need to 1) comply with the environmental regulations and 2) fulfil producers’ responsibility initiatives. In this context, the work described in this thesis investigates the applications of new leaching solvents, the ionic liquids (ILs), to recycle two materials, copper and decabromodiphenylether (DBDE), which are common in WEEE. A total of 18 ILs, methylimidazolium (MIM) and methylpyridinium (MPy) based, were prepared using a microwave-assisted method. These ILs were selected to allow characterisation of performance with respect to three parameters: hydrophobicity of the cation, polarity of a terminal functional group in the cation side chain, and the type of aromatic ring, in order to identify their effects on the solubility and extraction processes. All ILs were successfully characterised by IR spectroscopy, mass spectrometry and NMR. Hydrophobicity was measured by HPLC, and the retention factors compared to logP values predicted from Molinspiration. High correlation (>88%) was observed, which indicated that the predicted logP values were representative of the real hydrophobicity of the cation. Copper metal was not significantly dissolved in any of the ILs, and performance was therefore assessed with the dissolution of CuO. The dissolution tests were conducted at 70°C for ten minutes and the resultant solutions analysed for Cu by using atomic absorption spectroscopy. A short side chain and the presence of a strongly polarised functional group at the terminal position were required to achieve maximum dissolution. Furthermore, the short chain methylimidazolium system was better than methylpyridinium for dissolving CuO. Consequently, 1-(2-cyanoethyl)-1-methylimidazloium bromide was found to be the best solvent and dissolved 75.5 mg of Cu in one g of IL. High impact polystyrene (HIPS), containing 4.4% of DBDE, was prepared in order to test the extraction abilities of various non-substituted ILs. The extraction of DBDE from the polymer was conducted at 90°C for 2 h 45 min. The results indicated that high hydrophobicity was required to achieve the maximum extraction of DBDE, however, the percentage extraction remained very low (<10%). The low extraction was attributed to the fact that only the DBDE present on the outer surface of the polymer was extracted during the process. In spite of being more hydrophobic, MPy-based systems did not dissolve as much as MIM-based systems because they were more viscous. The high viscosity value actually hindered the diffusion process and ultimately reduced the extraction of DBDE. The effects of different factors on the extraction process were evaluated and the maximum extraction was achieved by using 1-octyl-3-methylimidazolium bromide at 110 °C. The results described in this thesis have identified and quantified the link between the structures of the ILs and extraction efficiencies in relation to their potential use for recovery of CuO and DBDE from WEEE. The recommendations for future work have also been identified. The results obtained in this work, however, have contributed to increase the knowledge about the properties of ILs and can be used in future research to design a large scale recycling process.
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Hydrogen production from anaerobic co-digestion of coffee mucilage and swine manure / Production d hydrogène par co-digestion anaérobie de mucilage du café et de lisier de porcHernandez Pardo, Mario Andres 22 November 2012 (has links)
Cette étude examine une approche alternative à l'utilisation de deux déchets provenant des activités agricoles et d'élevage développés en Colombie. Lisier de porc et de mucilage café ont été utilisés pour évaluer une co-digestion anaérobie processus axé sur la production d'hydrogène. En outre, les objectifs couvert une nouvelle étape dans le but de fermer le cycle des déchets fois. La thèse a été menéeen trois phases : 1. Evaluation de la productiond'hydrogène à partir de la co-digestion de mucilage café et du lisier de porc pendant la fermentation sombre ; 2. Évolution dans le temps de rétention par la surveillance des micro-organismes par qPCR et d'autres paramètres incluiding pH, le potentiel d'oxydo-réduction, et une pression partielle d'hydrogène ; 3. Traitement de l'effluent de processus de production d'hydrogène par digestion anaérobie avec production de méthane. Les résultats expérimentaux ont montré que les mélanges de deux déchets sont en mesure de produire de l'hydrogène. Un ratio substrat de 5:5, ce qui a été associé à un rapport C/N de 53, a été adapté pour la production d'hydrogène. En outre, la stabilité et l'optimisation du processus ont été évalués par l'augmentation du taux de charge organique influent. Ce fut la meilleure condition expérimentale en termes de taux moy en volume d'hydrogène cumulatif de production et de rendement qui étaient 2661 NmL, 760 NmL H2/Lwdet 43 NmL H2/gDCO, respectivement. Cette performance a été préservé au fil du temps, ce qui a été vérifié par la culture discontinue répétitive pendant 43 jours. Deux tendances ont été identifiées au cours du temps de rétention associée à l'hydrogène cumulatif similaire, mais avec des différences de phase de latence le temps et le taux de production d'hydrogène. T. thermosaccharolyticum était le genre dominant au cours de la tendance à court lié à la plus courte phase de latence de temps et plus le taux de production d'hydrogène. Les tendances de long ont été associées à une diminution de Bacillus sp. concentration au début des expériences, et avec le concours possible pour des substrats solubles entre T. thermosaccharolyticum et Clostridium sp. La troisième phase a montré que l'utilisation d'une deuxième phase pour produire du méthane était utile d'améliorer le traitement des déchets tant. Enfin, l'énergie totale produite à la fois pour les biocarburants ont montré des niveaux similaires avec d'autres processus. Cependant,l'hydrogène a été d'environ 10% de l'énergie totale produite dans le processus. En outre, les deux gaz peuvent être mélangés pour produire biohythane qui améliore les propriétés de biogaz. / This research investigates an alternative approach to the use of two wastes from agricultural and livestock activities developed in Colombia. Swinemanure and coffee mucilage were used to evaluatean anaerobic co-digestion process focused on hydrogen production. In addition, the aims covered a further stage in order to close the cycle of the both wastes. The thesis was conducted in three phases : 1. Evaluation of hydrogen production from the co-digestion of coffee mucilage and swine manure during dark fermentation ; 2. Trends over retention time through the monitoring of microorganisms by quantitative PCR and other parameters incluiding pH, oxidation reduction potential, and hydrogen partial pressure ; 3. Treatment of the effluent from hydrogen production process by anaerobic digestion with methane production. The experimental results showed that mixtures of both wastes are able to produce hydrogen. A substrate ratio of 5:5, which was associated with a C/N ratio of 53, was suitable for hydrogen production. Moreover, the stability and optimization of the process were evaluated by increasing the influent organic load rate. This wasthe best experimental condition in terms of average cumulative hydrogen volume, production rate and yield which were 2661 NmL, 760 NmLH2/Lwd and 43 NmL H2/gCOD, respectively. This performance was preserved over time, which was verified through the repetitive batch cultivation during 43 days. Two trends were identified over retention time associated with similar cumulative hydrogen, but with differences in lag-phase time and hydrogen production rate. T.thermosaccharolyticum was the dominating genus during the short trend related to the shortest lag phase time and highest hydrogen production rate. The long trends were associated with a decrease of Bacillus sp. concentration at the beginning of the experiments and with the possible competition for soluble substrates between T.thermosaccharolyticum and Clostridium sp. The third phase showed that the use of a second stage to produce methane was useful enhancing the treatment of both wastes. Finally, the overall energy produced for both biofuels (Hydrogen andmethane) showed similar levels with other process. However, hydrogen was around the 10% of the overall energy produced in the process. In addition, both gases could be mixed to produce biohythane which improves the properties of biogas.
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Reciclagem do resíduo de cromo da indústria do curtume como pigmentos cerâmicos. / Recycling of chromium waste of leather industry as ceramic pigments.Abreu, Míriam Antonio de 29 June 2006 (has links)
Este trabalho apresenta uma alternativa para a reciclagem dos resíduos de cromo da Indústria do Curtume incorporando-os na formulação de pigmentos cerâmicos. Inicialmente o resíduo de cromo foi tratado sendo realizada a extração de sais solúveis, cloretos, sulfatos, carbonatos e posterior calcinação para a eliminação de matéria-orgânica, tornando assim, viável sua utilização como pigmentos. Os ensaios realizados utilizaram as seguintes técnicas: fluorescência de raios X, espectroscopia por emissão de plasma atômico, espectrofotometria com difenilcarbazida, análises termodiferencial e termogravimétrica, difração de raios X, eletroforese capilar e microscopia eletrônica de varredura. Através destas análises foram feitos estudos das composições de pigmentos que favoreçam a incorporação do cromo a vidrados cerâmicos. A incorporação foi avaliada por testes de lixiviação ácida e identificação por eletroforese capilar e absorção atômica, confirmando teores abaixo dos limites especificados pela norma NBR10004. Foi possível incorporar até 10% do resíduo de cromo na produção de vidrados cerâmicos, resultando em boas características de cor e textura no vidrado final, mostrando o grande potencial de reciclagem dos resíduos de cromo da indústria do curtume como pigmentos cerâmicos. / In this work, an alternative for recycling the chromium waste from the leather industry, incorporating it to formulations of ceramic pigments was studied. Firstly, the characterization of chromium waste was performed, as well as the extraction of soluble salts, chlorides, sulfates, ad carbonates. After that, the calcination, for the elimination of the organic matter to turn viable the use of the waste as ceramic pigments was performed. The various stages were evaluated by: X-ray Fluorescence, Inductively Coupled Plasma-Atomic Emission Spectrometer, Atomic Absorption, Spectroscopy with Dyphenylcarbazide, Differential Thermal Analysis and Thermogravimetry, X-ray Diffraction, Capillary Electrophoresis and Scanning Electron Microscopy. The results indicated that it is possible the incorporation of the waste into the ceramic glazes. Leaching tests were performed with the developed glazes and the chemical compositions of the leachates were determined by capillary electrophoresis and atomic absorption, confirming amounts lower than the ones specified by the Brazilian standard NBR10004. It was possible to incorporate 10wt.% of chromium residue in the production of inorganic pigments, resulting in glazes with good characteristics of color and texture, showing the great potential of recycling chromium waste from the tannery industry in the fabrication of pigments for the Ceramic Tile Industry.
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Biodigestão e co-digestão anaeróbias de cama de frangos com água residuária de suinocultura / Anaerobics biodigestion and co-digestion of poultry litter with swine wastewaterVicente Junior, Donizete Jose 13 July 2012 (has links)
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Previous issue date: 2012-07-13 / Brazil has great potential in food production, although the large scale production of grains and animal protein has increased waste generation. This justifies the study of recycling practices, such as biodigestion and anaerobic co-digestion of wastewater, excreta and solid waste from farms and processing products since the processing of potential polluting waste into biofertilizers and biogas has contributed to effective sanitation and added value to the final product. The studied wastes were reused poultry litter from six, seven and eight lots and sieved swine wastewater (SWW), from piglet production unit. Two trials were carried out: the first one aimed at verifying which system, biodigestion or anaerobic co-digestion, has recorded the greatest potential for biogas production. With those results from the first trial, the second one could be started to determine the best hydraulic retention time (40 or 55 days), according to the following evaluated parameters: pH, electrical conductivity (EC), reduction of both total solids (TS) and volatile solids (VS), reduction of chemical oxygen demand (COD), N, P, K, Ca, Mg, Zn, Cu, Fe, Mn and Na contents, both in influent and effluent as well as the potential biogas production and analysis of total and thermo-tolerant coliforms. The results have shown higher biogas production (p <0.05) in treatments that used anaerobic co-digestion with SWW (0.179, 0.158 and 0.117 m3 kg added TS) for poultry litter with six, seven and eight lots, respectively. In this trial, there was no interaction among factors (poultry litter and used wastewater) or differences among treatments for COD decrease. For the second test, when hydraulic retention times were compared, the biogas production was statistically higher (p <0.05) in 55 day (0.04, 0.05 and 0.03 m3/kg TS added), respectively for poultry litter with six, seven and eight lots. According to COD decrease, the largest decreases (p <0.05) were observed at 55 days (45.83, 67.49 and 29.45%), respectively, for the poultry litter with six, seven and eight lots. There was no total or thermo-tolerant coliform in biofertilizer, in both trials. According to the chemical composition of biofertilizers, there was higher concentration of nutrients in effluent when compared to the influent due to carbon losses in biogas for both trials. In the first trial, the Mg levels remained the same in both biofertilizers from co-digestion as in anaerobic digestion. For other nutrients, the biofertilizer from co-digestion of the increases ranged from 20.2% for Ca up to 92% for N. In the first trial, both processes were compared and there was an increase on nutrients concentration in co-digestion biofertilizers and the increases ranged from 20.2% for Ca up to 92% for N. For micronutrients, the variation was from 55.2% up to 904.7% in Cu. Thus, it was concluded that the anaerobic co-digestion of sieved swine wastewater and poultry litter with six, seven or eight lots plus a 55 day hydraulic retention time is the best option for recycling energy and nutrients, although it has resulted in greater concentration of Cu and Zn in biofertilizer / O Brasil apresenta grande potencialidade na produção de alimentos, porém, a produção em larga escala de grãos e proteína animal tem levado ao aumento da geração de resíduos. Este fato justifica o estudo de práticas de reciclagem, tais como a biodigestão e a co-digestão anaeróbia de águas residuárias e resíduos sólidos oriundos de criatórios e beneficiamentos, pois a transformação de resíduos potencialmente poluidores em biofertilizante e biogás contribui para o saneamento eficaz e agrega valor ao produto final. Os resíduos utilizados nesta pesquisa foram camas de frango de seis, sete e oito lotes, além de água residuária da suinocultura (ARS) peneirada, proveniente de unidade produtora de leitões. Foram implantados dois ensaios: no primeiro ensaio, objetivou-se verificar qual dos processos, a biodigestão ou a co-digestão anaeróbia apresentaria o maior potencial de produção de biogás. Com os resultados do primeiro ensaio, iniciou-se o segundo para determinar qual o melhor tempo de retenção hidráulica (40 ou 55 dias) em função dos parâmetros avaliados, a saber: pH; condutividade elétrica (CE); redução de sólidos totais (ST) e sólidos voláteis (SV); redução da demanda química de oxigênio (DQO); teores de N, P, K, Ca, Mg, Zn, Cu, Fe, Mn e Na, tanto no afluente quanto no efluente, além dos potenciais de produção de biogás e análise de coliformes totais e termotolerantes. Como resultados, observaram-se maiores produções de biogás (p<0,05) nos tratamentos em que se empregou a co-digestão anaeróbia com ARS: 0,179; 0,158 e 0,117 m3 por kg de ST adicionados, para as camas de frango com seis, sete e oito lotes, respectivamente. Neste mesmo ensaio, não se observou interação entre os fatores (cama e águas utilizadas) nem diferenças estatísticas entre os tratamentos para a redução de DQO. Para o segundo ensaio, ao serem comparados os tempos de retenção hidráulica, observou-se produção de biogás estatisticamente maior (p<0,05) no tempo de 55 dias: 0,04; 0,05 e 0,03 m3 por kg ST adicionados, respectivamente, para as camas de frango com seis, sete e oito lotes. Quanto à redução de DQO, as maiores reduções (p<0,05) foram observadas aos 55 dias: 45,83; 67,49 e 29,45%, respectivamente, para camas de seis, sete e oito lotes. Não foram observados coliformes totais nem termotolerantes no biofertilizante, em ambos os ensaios. Com relação à composição química dos biofertilizantes, observou-se, de maneira geral, maior concentração de nutrientes no efluente quando comparado ao afluente, devido às perdas de C via biogás, em ambos os ensaios. No primeiro ensaio, onde foram comparados os dois processos, houve aumento na concentração de macronutrientes, no biofertilizante proveniente da co-digestão, os incrementos variaram desde 20,2% para o Ca até 92% para o N. Para os micronutrientes, a variação foi desde 55,2% para o Na até 904,7% para o Cu. Concluiu-se que a co-digestão anaeróbia entre água residuária de suinocultura peneirada e cama de frango com seis, sete ou oito lotes, com tempo de retenção hidráulica de 55 dias, é a melhor opção para a reciclagem energética e de nutrientes, porém resulta em maior concentração de Cu e Zn no biofertilizante
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Conversão termoquímica do resíduo do triturador de sucata (RTS) de uma siderúrgicaPerondi, Daniele January 2017 (has links)
Diferentes resíduos são gerados pelas indústrias siderúrgicas, dentre eles o resíduo dos trituradores de sucata (RTS). O destino mais utilizado para o RTS pelas indústrias siderúrgicas brasileiras é o aterro de resíduos industriais. A pirólise se apresenta como uma alternativa para o reaproveitamento do RTS. O objetivo deste trabalho foi avaliar o efeito de diferentes parâmetros operacionais sobre as propriedades e o rendimento dos produtos do processo de pirólise do RTS para fins de um posterior aproveitamento. Um reator de pirólise de leito fixo foi utilizado e as seguintes variáveis foram testadas fazendo-se uso de um planejamento experimental 2k: temperatura (500, 600 e 700 ºC), taxa de aquecimento (5, 20, 35 ºC/min), vazão de gás inerte (N2) (0,03, 0,44 e 0,76 L/min) e razão CaO/RTS (0, 1 e 2). A utilização de uma taxa de aquecimento menor, associada a presença de CaO, resultou nos maiores rendimentos de gás não-condensável (> 50%). O poder calorífico deste gás, aumentou com o incremento da razão CaO/RTS. Este aumento foi atribuído a captura in situ do CO2. A utilização de uma vazão maior de gás inerte, também favoreceu o aumento do poder calorífico do gás não-condensável. Os maiores valores obtidos (25 MJ/Nm3) são apreciáveis, considerando o poder calorífico de outros combustíveis. Os maiores rendimentos de char (> 24%) foram obtidos nos experimentos com a utilização de uma temperatura menor, associada a ausência de CaO. A utilização de uma taxa de aquecimento mais elevada resultou em maiores rendimentos de voláteis condensáveis. Os menores rendimentos de voláteis condensáveis foram obtidos quando a vazão de inerte foi menor. Também foi possível verificar que, houve um aumento do rendimento de voláteis condensáveis com a presença de CaO para a temperatura de 700 ºC. Este comportamento foi atribuído ao maior rendimento global de estireno nas referidas condições operacionais. O rendimento global de 2,4-dimetil-1-heptano também apresentou comportamento semelhante ao observado para o rendimento de voláteis condensáveis, indicando que o AlCl3 pode ter atuado como catalisador da pirólise do PP presente no RTS. Com o aumento da razão CaO/RTS, houve uma redução da concentração de CO2. A redução da concentração de CO2 na presença de CaO está associada a formação de CaCO3. A retenção de cloro no char foi mais elevada nos ensaios conduzidos na presença de CaO. Verificou-se uma redução da retenção de cloro no char com o aumento da temperatura para os ensaios conduzidos na presença de CaO. Uma diminuição da retenção de metais no char foi verificada nos experimentos conduzidos com CaO para os seguintes metais: Co, Cu, Cr, Fe, Ni e Zn. A remoção do cloro permitiria conduzir o processo de pirólise a temperaturas mais elevadas, aumentando a Eficiência Energética mínima (EE) do processo. Desta forma, fica clara a necessidade da remoção do cloro do RTS antes do processo de pirólise, pois a partir disto o uso do CaO contribuiria para o aumento da EE e da retenção de metais no char, e consequentemente da desejabilidade global. / Different wastes are generated by steel industries, among them the shredder residue (SR). The most commonly used destination for SR by Brazilian steel industry is the landfill of industrial waste. The pyrolysis can be considered a solution to this problem. The aim of this work was to evaluate the effects of different operating parameters upon the properties and yield of the SR pyrolysis process products for later use. A fixed bed pyrolysis reactor was used and the following variables were tested using a 2k experimental design: temperature (500, 600 and 700 ºC), heating rate (5, 20, 35 ºC/min), flow rate of inert gas (N2) (0.03, 0.44 and 0.76 L/min) and CaO/SR ratio (0, 1 and 2). The use of a lower heating rate, associated with the CaO presence, resulted in higher yields of non-condensable gas (> 50%). The calorific value of this gas increased with the growth of the CaO/SR ratio. This increase was attributed to an in situ CO2 capture. The use of a higher flow rate of inert gas also favored the increase in the calorific power of the non-condensable gas. The highest values (25 MJ/Nm3) are appreciable considering the calorific value of other fuels. The highest char yields (> 24%) were obtained in the experiments using a lower temperature associated with the absence of CaO. The use of a higher heating rate resulted in higher yields of condensable volatiles. The lower yields of condensable volatiles were obtained when the inert flow rate was lower. It was also possible to verify that there was an increase in the condensable volatiles yield with the CaO presence at a temperature of 700 ºC.This behavior was attributed to the higher styrene overall yield under these operating conditions. The 2,4-dimethyl-1-heptane overall yield also presented a similar behavior to that observed for the condensable volatiles yield, indicating that the AlCl3 may have acted as a catalyst for the PP pyrolysis present in the SR. With the increase in the CaO/RTS ratio, there was a reduction in the CO2 concentration. The CO2 concentration reduction in the CaO presence is associated with the CaCO3 formation. The chlorine retention in the char was higher in the experiments conducted with CaO presence. A reduction in the chlorine retention in char was observed with increasing temperature for the experiments conducted with CaO presence. A decrease in metal retention in the char was verified in the experiments conducted with CaO for the following metals: Co, Cu, Cr, Fe, Ni and Zn. Chlorine removal would allow the pyrolysis process to be conducted at higher temperatures, increasing the minimum energy efficiency (EE) of the process. Therefore, it is clear the need to remove chlorine from the SR before the pyrolysis process, since, the CaO use would contribute to the EE increase and the retention of metals in the char, and consequently the global desirability.
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