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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Production and Characterization of Coal-Biomass Briquettes

Dohm, Erich David 24 January 2014 (has links)
Roll press briquetting of coal-biomass mixtures presents a significant opportunity to address feedstock challenges associated with co-utilization of coal and biomass in existing coal-fired facilities. However, several technical and economic barriers require further investigation prior to industrial utilization of coal-biomass briquettes. The scientific contributions presented in this dissertation are intended to address the most critical technical challenges pertaining to coal-biomass briquette feedstocks. As with any product of an agglomeration process, the primary technical challenge regarding coal-biomass briquettes is achieving and maintaining a high level of quality from production to utilization. Several laboratory-scale research investigations were conducted to address this challenge. The first study was conducted to identify, develop and refine methods to characterize the most important physical properties indicative of coal-biomass briquette quality. The outcome of this work is a set of recommendations for novel and refined methods to characterize important coal-biomass briquette properties. The second study was conducted to develop a novel method to identify the optimum water content of coal-biomass blends prior to briquette production. As a result of this study, the Briquette Proctor Test was developed to minimize the time and materials required to identify the optimum water content that corresponds to maximum quality of coal-biomass briquettes. The third study was conducted to evaluate the influence of feedstock variables, additive variables, and roll press operating parameters in the production of coal-biomass briquettes from various coal and biomass types. From this study, the influence of each parameter on the quality of briquettes was determined and optimum conditions were identified for a variety of coal-biomass mixtures. The fourth and final study was conducted to develop and evaluate methods to improve the water resistance of coal-biomass briquettes using wood-derived chemicals. Using these chemicals, the novel coating method developed in this study significantly improved the water resistance and weathered durability of coal-biomass briquettes. / Ph. D.
2

Selection and Implementation of an Optimal System to Handle Garbage in Kigali, Rwanda

Kahigana, Innocent January 2011 (has links)
Reports from various institutions claim that garbage management in Rwanda has had diverse effects on both the natural environment and human society. Such claims prompted for an exploratory study to find out an optimal system to handle solid waste in Kigali City. The study considered a literature review and primary data from 400 randomly selected citizens. They were surveyed about their opinions on which system they perceived to be the optimal to handle garbage in Kigali City. The computer software Web-Hipre was used to analyze data on the three systems considered to handle solid waste in Rwanda: briquetting, composting, and incineration.The results indicate briquetting as the optimal alternative to handle solid waste from homesteads and workplaces of Kigali City. Briquetting considers production of solid fuels that may reduce destruction of forests for fuel. Other major reasons for briquetting, highlighted by respondents, include improved kitchen hygiene and sanitation and replacement of charcoal for a less dusty fuel. Economic factors governed surveyed participants to prioritise briquetting system to handle solid waste in Kigali. Composting may be considered for transforming organic materials into mulch to support farming activities in rural areas as well as gardening in the towns. However, a centralised incineration system is presently not suitable. The private sector has so far not fully been engaged in the transformation of solid waste into bioenergy in Rwanda.
3

Selection and implementation of an optimal system to handle garbage in Kigali, Rwanda

Innocent, Kahigana January 2011 (has links)
Reports from various institutions claim that garbage management in Rwanda has had diverse effectson both the natural environment and human society. Such claims prompted for an exploratory study to find outan optimal system to handle solid waste in Kigali City.The study considered a literature review and primary data from 400 randomly selected citizens. They weresurveyed about their opinions on which system they perceived to be the optimal to handle garbage in KigaliCity. The computer software Web-Hipre was used to analyze data on the three systems considered to handlesolid waste in Rwanda: briquetting, composting, and incineration.The results indicate briquetting as the optimal alternative to handle solid waste from homesteads and workplacesof Kigali City. Briquetting considers production of solid fuels that may reduce destruction of forests for fuel.Other major reasons for briquetting, highlighted by respondents, include improved kitchen hygiene andsanitation and replacement of charcoal for a less dusty fuel.Economic factors governed surveyed participants to prioritise briquetting system to handle solid waste in Kigali.Composting may be considered for transforming organic materials into mulch to support farming activities inrural areas as well as gardening in the towns. However, a centralised incineration system is presently notsuitable. The private sector has so far not fully been engaged in the transformation of solid waste into bioenergyin Rwanda.
4

Komplexní posouzení energetické náročnosti výroby granulí pro vytápění z obnovitelných zdrojů / Comprehensive Assessment of Energy Demand in Production of Granules for Renewable Resources Heating

STERNBERG, Jiří January 2015 (has links)
The first part of the graduation thesis deals with renewable resources, utilization possibilities of biomass and plant phytomass. The most common sources from which phytomass is obtained, are also mentioned here. A great deal of attention is paid to selected energetic plants included into the experiment. It is Sorrel Rumex OK-2 (Rumex tianschanicus x Rumex patientia) and Poppy seed (Papaver Somniferum). Further there are summarized the processes necessary for separating and pressing of biomass into granules for direct combustion. Within the research, two-year experience of growing sorrel stand is described. On the basis of performed technological operations in the stand, energy demands of growing are calculated. The real usage of energy at the production of one tonne of granules is measured. When labour costs are taken into account I can say that the expenses for the production of one tonne of briquettes from biomass would be 4 592 CZK, which is a non-competitive sum.
5

Blendas de carvão vegetal e carvão mineral para a produção de briquetes / Characterization of blend and briquetes of charcoal and coals

Barros, João Lúcio de 25 May 2014 (has links)
Submitted by Milena Rubi (milenarubi@ufscar.br) on 2016-10-25T23:33:10Z No. of bitstreams: 1 BARROS_Joao_2014.pdf: 6489061 bytes, checksum: 0cb2ffbbdb2ad52ec3e54efd745b9ac1 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2016-10-25T23:34:13Z (GMT) No. of bitstreams: 1 BARROS_Joao_2014.pdf: 6489061 bytes, checksum: 0cb2ffbbdb2ad52ec3e54efd745b9ac1 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2016-10-25T23:34:24Z (GMT) No. of bitstreams: 1 BARROS_Joao_2014.pdf: 6489061 bytes, checksum: 0cb2ffbbdb2ad52ec3e54efd745b9ac1 (MD5) / Made available in DSpace on 2016-10-25T23:34:35Z (GMT). No. of bitstreams: 1 BARROS_Joao_2014.pdf: 6489061 bytes, checksum: 0cb2ffbbdb2ad52ec3e54efd745b9ac1 (MD5) Previous issue date: 2014-05-25 / Não recebi financiamento / Brazil produces about 37 million cubic meters of charcoal per year whit an increasing due to the gradual coal replacement, once the coal mined in Brazil does not have adequate levels of carbon for some purposes, such as power generation. However, the large amount of coal found in all terrestrial crust propitiates an extremely low cost this product. Regarding to it, whit the intent to add value to the coal and provide an adequate destination to by-product (fine) of the charcoal, it was made briquettes of coal blends. For briquettes production it was used coal and charcoal fines, corn starch and boiling water at different proportions, summing up 25 treatments. Ten samples were made for each treatment, summing 250 specimens, wich were analyzed by the moisture content, proximate analysis, density, mechanical strength and thermal analysis. The treatments without the addition of binder were discarded because briquettes could not be formed from them. Other treatments had good features, reaching satisfactory results expect in relation to the formation briquettes (average mechanical strength of 0,2 MPa), presenting good mechanical strength for commercial application. According to the increased proportion of charcoal in the blend, the produced briquette achieved better results, mainly to thermal properties due to higher fixed carbon content (compared to coal) and reduced ash content, an appropriate behavior for various industrial and even residential applications. It was concluded that the use of by-products from vegetable and coal briquettes was technically feasible, providing advantageous physical characteristics for storage and transportation. / O Brasil produz aproximadamente 37 milhões de metros cúbicos de carvão vegetal por ano, e o crescimento tende a aumentar devido à gradativa substituição do uso de carvão mineral, uma vez que o carvão mineral extraído no Brasil não possui níveis de carbono adequados para diversas finalidades, como por exemplo, a geração de energia. Porém, a grande quantidade de carvão mineral encontrada em praticamente toda a crosta terrestre faz com que esse produto tenha um custo extremamente baixo. Diante disto, objetivou-se agregar valor ao carvão mineral e proporcionar uma destinação adequada ao subproduto (finos) do carvão vegetal, com a produção de briquetes de blendas de carvão. Para a produção dos briquetes foram utilizados os finos de carvão mineral e carvão vegetal, além do amido de milho e água fervente em diferentes proporções, totalizando 25 tratamentos. Para cada tratamento foram confeccionadas dez amostras, totalizando 250 corpos de prova. Foram realizadas as análises de umidade, análise imediata, densidades, resistências mecânicas e análise térmica. Os tratamentos sem a adição de aglutinante foram descartados, pois não houve a formação dos briquetes. Os demais tratamentos obtiveram boas características, atingindo resultado considerado satisfatório esperado em relação à formação dos briquetes (resistência mecânica média de 0,2 MPa). De acordo com o aumento da proporção de carvão vegetal na blenda, o briquete atingiu melhores resultados, principalmente em relação ás propriedades térmicas, devido ao maior teor de carbono fixo (em relação ao carvão mineral) e diminuição de teores de cinzas, comportamento adequado para diversas aplicações industriais e até residenciais. Concluiu-se que a utilização dos subprodutos de carvões vegetal e mineral na forma de briquetes foi tecnicamente viável, com características físicas vantajosas para o armazenamento e transporte.
6

Briquetagem de residuos vegetais : viabilidade tecnico-economica e potencial de mercado / Briquetting of vegetal residue : technical and economic feasibility and market potential

Filippetto, Daniele 15 February 2008 (has links)
Orientadores: Carlos Alberto Luengo, Felix Eliecer Fonseca Felfli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-10T03:34:37Z (GMT). No. of bitstreams: 1 Filippetto_Daniele_M.pdf: 2143026 bytes, checksum: 1e445cc88f2aace4fb7952fdfced1f19 (MD5) Previous issue date: 2008 / Resumo: Neste trabalho desenvolveu-se um estudo técnico-econômico sobre a briquetagem de resíduos vegetais focado na tecnologia da briquetadeira do tipo parafuso sem-fim, ainda inédita no Brasil. A vantagem dessa tecnologia é a produção de briquetes mais compactos, que além de servir para combustão direta, também são adequados para torrefação, carbonização e gaseificação. Investigou-se preliminarmente o mercado de briquetes no Brasil, através de um levantamento das empresas produtoras, que proporcionou dados sobre tecnologias empregadas, quantidades produzidas e preços de venda. Esse levantamento sugeriu a existência de um potencial de mercado para introdução de prensas de parafuso sem-fim. Estudou-se o desempenho de um protótipo de briquetadeira de parafuso sem-fim construído pela empresa Bioware Ltda, em parceria com a Universidade Estadual de Campinas. Avaliaram-se dados de produtividade e gasto de energia bem como as propriedades físico-químicas dos briquetes produzidos. Constatou-se o bom desempenho técnico do protótipo e a boa qualidade dos briquetes, de acordo com dados encontrados em literatura. Realizou-se um estudo de caso de uma planta de briquetagem que evidenciou a viabilidade econômica dessa tecnologia / Abstract: In this work a technical and economic study about briquetting of vegetable residues focused on screw briquetting technology ¿ still not introduced in Brazil ¿ was developed. The advantage of this technology is the production of more compact briquettes that, as well as for direct burning purpose, are suitable for torrefaction, carbonization and gasification. The Brazilian briquettes market was previously investigated by means of a survey on production factories. This survey provided information about present technologies, briquettes production quantities, and sale price. The investigation suggested the existence of a market potential for introducing screw briquetting machines. The performance of a prototype of screw briquetting machine built by Bioware Ltda in partnership with the State University of Campinas was examined. Data on productivity and energy requirements were investigated and chemical and physical properties of produced briquettes were analyzed. A good technical performance of the machine and a good quality of the briquettes were observed. A case study on a screw briquetting plant was investigated and it proveded economic feasibility / Mestrado / Mestre em Planejamento de Sistemas Energéticos
7

Systém zpracování kovového odpadu z řezných procesů / Metal waste processing system from cutting processes

Partlová, Veronika January 2021 (has links)
Diploma thesis will be focuses on the processing of steel chips, explanation of general con-cepts, the division of chips according to their origin, their types and examples of some machines that are related to the chip processing system. It will also describe which law to follow when sor-ting waste like this, how to recycle it and how much this topic is connected with the ecological point of view. The second part of the work will be focused on the processing of the aluminium waste from the production of aluminium components. It contains a specific example of the calculation of a proposal to change the treatment of the waste and the return on investment in this change. The reason why to undergo this change is described too and in what way it will be beneficial.
8

Design briketovacího lisu kovových třísek / Design of briquetting press for metal chips

Matušková, Adéla January 2020 (has links)
This dissertation deals with design of briquetting press of metal splinters. Dissertation reacts to non-complexity of solutions of present products. Goal is to raise the attractivity of the machine and related increase in awareness of this machine with ecological and economic benefits. Dissertation emphasizes preservation of functionality, consideration of ergonomics and safety of the machine.
9

Briquetting and Reduction of DRI/HBI Fines for Next-Generation Iron and Steel Making Technology

NITUNGA, Eddy-Nestor January 2024 (has links)
The current transition from Blast Furnace (BF) to Hydrogen-Direct Reduction (H-DR) is an initiative to reduce the carbon footprint in Iron and Steel production. The shift from traditional coke-based Iron and Steel making to a green H-DR requires new innovative technologies, underscoring the importance of collective efforts in this field. The production of DRI/HBI fines, which account for 1-2% wt. of DR production, poses a significant challenge for the iron and steel industries. These fines, rich in iron, are generated inside the plant during the handling, production, and transportation process. Their recycling in the DR process is difficult without proper agglomeration. Here, briquetting emerges as a promising solution to this challenge. This research work is dedicated to exploring the use of innovative binders in briquetting the DRI/HBI fines. It aims to understand the H2 -based reduction behaviour of the briquettes and the role of embedded biocarbon in enhancing resource efficiency. The study also investigates the impact of binders on the mechanical strength, moisture content, and compaction pressure of the briquettes. The optimized briquettes are then subjected to H2-based reduction using a thermogravimetric technique (TGA) followed by characterization by XRF, XRD, and LECO analysis, and mechanically evaluated to assess their potential in the next-generation H2-based Iron and Steel Making. Keywords: DRI/HBI Fines, Organic binders, Briquetting, H2 Reduction, Biocarbon, Recycling, Resource Efficiency
10

Estudo da obtenção de briquetes autorredutores de minério de ferro e carvão fóssil endurecidos por tratamento térmico. / Development of composite briquettes of iron ore and coal hardened by heat treatment.

Narita, Cesar Yuji 10 November 2014 (has links)
Nos últimos anos, novas tecnologias têm sido desenvolvidas para a redução da emissão de gás carbônico, um dos principais causadores do efeito estufa. Na indústria de ferro e aço, grande emissora de gás carbônico, tecnologias para uso mais eficiente de carvão fóssil tem sido desenvolvidas. Uma dessas tecnologias é o produto chamado de CCB (Carbon Composite Iron Ore Hot Briquette), um composto de minério de ferro e carbono briquetado a quente que usa a plasticidade térmica do carvão fóssil como aglomerante para aumento da resistência mecânica do aglomerado. Esse produto tem como vantagens a alta velocidade de reação e alta resistência mecânica a altas temperaturas, diferentemente das pelotas autorredutores que usam aglomerantes inorgânicos. Os objetivos deste trabalho foram: (a) propor um método para a fabricação de aglomerados autorredutores de minério de ferro e carvão fóssil via briquetagem a frio seguida de tratamento térmico; (b) identificar a principais variáveis de processo de fabricação; e (c) estudar o comportamento cinético durante a redução dos briquetes produzidos. Para fabricar os briquetes foram utilizados dois métodos de briquetagem, um em matriz cilíndrica de compressão uniaxial, e outro em prensa de rolos. Foram identificadas as principais variáveis de processo na fabricação dos briquetes: temperatura de tratamento térmico; tamanho de partícula dos componentes da mistura; características do carvão fóssil; pressão de compressão na conformação dos briquetes; proporção dos componentes; e taxa de aquecimento do tratamento térmico. A qualidade dos briquetes foi mensurada por sua resistência à compressão. Foi observado que a obtenção de um briquete autorredutor comparável com os CCBs, deve levar em conta as seguintes condições de fabricação: (a) tamanho de partícula do carvão fóssil entre 0,105 e 0,053 mm (150 e 270 mesh); (b) quantidade de carvão fóssil na mistura entre 25 e 30% em peso; e (c) temperatura de tratamento térmico de 500°C. Além disso, quanto maior a taxa de aquecimento do tratamento térmico, maior a resistência à compressão dos briquetes. A cinética de redução dos briquetes autorredutores tratados termicamente é bastante sensível à temperatura (E = 369 kJ/mol), principalmente quando comparada a pelotas autorredutoras de minério de ferro e carvão vegetal (E 200 kJ/mol). / In recent years, new technologies have been developed to reduce carbon dioxide emissions, one of the main causes of the greenhouse effect. Innovative energy saving technologies have been developed to improve the efficiency of coal usage, especially in the iron making industry, which emits large amounts of carbon dioxide. One of these technologies is a product known as CCB (Carbon Composite Iron Ore Hot Briquette), a self-reducing carbon composite iron ore that uses the thermal plasticity of coking coals as a binder to enhance the mechanical strength of the agglomerate. This product has advantages such as high reaction rate and high mechanical strength at high temperatures when compared against self-reducing pellets that uses inorganic binders. The objectives of this study are: (a) to propose a method for manufacturing composite briquettes of iron ore and coal hardened by heat treatment; (b) to identify the main process variables of the fabrication; and (c) to study the agglomerate reduction kinetics. Two methods of briquetting have been employed, one using a cylindrical die and the other using a laboratory roller press. The main process variables for manufacturing the briquettes have been identified: the heat treatment temperature; the particle size of the components; the coal characteristics; the briquetting pressure; the proportion of the components; and the heating rate. Compressive strength tests have been performed. It was observed that obtaining a self-reducing briquette as strong as the CCB should consider the following fabrication conditions: (a) coal particle size between 0,105 and 0,053 mm (150 and 270 mesh); (b) coal amount in the mixture between 25 and 30 wt%; and (c) heat treatment temperature of 500°C. Also, higher heating rates showed higher briquette compressive strengths. The self-reducing briquettes reduction kinetics are very sensitive to temperature (E = 369 kJ/mol), especially when compared against self-reducing pellets of iron ore and charcoal (E 200 kJ/mol).

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