Encontrados 17 documentos, a visualizar página 1 de 2

Tecnologias CAC e Inquéritos de Percepção da Opinião Pública sobre “O papel da ...

O carvão e outros combustíveis fósseis, continuarão a ser, por décadas, a principal matéria-prima energética para as Centrais Térmicas, não obstante os esforços para, dentro do possível, substituir os combustíveis fósseis por fontes de energia renovável.Tal como está, hoje, bem documentado, a produção de gases com efeito estufa (GEE), designadamente CO2, resulta da combustão dos ditos combustíveis fósseis, send...

Overview CO2 Geological Sequestration

Comparative study of the influence of minerals in gas sorption isotherms of thr...

This investigation compares the gas adsorption behaviour and capacity of three bituminous coals from South Africa, of similar rank, by assessing the characteristics of the raw coal, as well as the resulting float and sink fractions (at 1.80 cm3/g) obtained by density separation of crushed coal samples. Calculations were also made to obtain the raw coal gas storage capacity from the weighted contribution of both...

The identification of unusual microscopic features in coal and their derived ch...

During the petrographic study of seven feed coals from different origins, it was found that these coals presented microfeatures such as: material size, shape, weathering, thermally affected particles and contamination. After devolatilization under fluidized bed conditions, some chars presented the consequences of the above mentioned microfeatures, i.e., unreacted coal, unswelled particles, coatings and microstr...

Combustion studies in a fluidised bed—The link between temperature, NOx and N2O...

Five commercially available high volatile bituminous coals from different origins were studied with the objective of characterizing their petrographic nature with respect to emissions of NOx and N2O. The chars produced [at temperatures ranging from 700 to 1000 °C] from these coals were also petrographically analyzed to assess the contribution of char to NOx and N2O formation during combustion. Vitrinite-rich co...

Characterization of Coal Maceral Groups by Micro-Raman Spectroscopy

Comunicação apresentada no 7º Congresso de Geoquímica dos Países de Língua Portuguesa, Maputo (Moçambique), Setembro 2003. ; Uma caracterização rápida e não-destrutiva da organização estrutural do material carbonoso pode ser conseguida através da espectroscopia micro-Raman, uma vez que podem ser obtidos espectros de áreas micrométricas. Uma aplicação óbvia desta técnica é a caracterização pontual de macerais d...

A study on coal blending for reducing NOx and N2O and levels during fluidized b...

The objective of the study was to investigate the effect of blending on the emissions of NOx and N2O during the fluidized bed combustion of five coals with different levels of nitrogen, volatile matter, and fixed carbon contents, and diverse coal and char petrographic composition. The devolatilization chars were produced in a fluidized bed combustor. Using the petrographic analyses of the coals, sixteen coal bl...

The role of coal “cleat system” in Coalbed Methane Prospecting/Exploring: A new...

The Coalbed Methane (CBM) generated by coal is located in coal pores and the drainage of the coalbed gas to the production well is made through the so-called "cleat system", i.e., the natural fracture network of coal. This justifies the classic method of CBM production by providing fracture-stimulation with fluids under pressure to open coal natural fractures. However, natural fracturing system of any coal is ...

Prerequisites, general criteria and primary studies required in the CoalbedMeth...

The main objectives of this paper are: (i) to review and summarize current concepts of Coalbed Methane (CBM) genesis and storage, (ii) to highlight and present the principal procedures and methodologies concerned with prospecting/exploring of CBM leading to a sequence of basic criteria to be followed at an early stage and, subsequently, during research and exploration, and (iii) to present a list of the most im...

The measurement of coal porosity with different gases

Sorption processes can be used to study different characteristics of coal properties, such as gas content (coalbed methane potential of a deposit), gas diffusion, porosity, internal surface area, etc. Coal microstructure (porosity system) is relevant for gas flow behaviour in coal and, consequently, directly influences gas recovery from the coalbed. This paper addresses the determination of coal porosity (namel...