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Emissions of NO(x) and SO(2) from Coals of Various Ranks, Bagasse, and Coal-Bagasse Blends Burning in O(2)/N(2) and O(2)/CO(2) Environments

KAZANC, Feyza; KHATAMI, Reza; CRNKOVIC, Paula Manoel; LEVENDIS, Yiannis A.
Fonte: AMER CHEMICAL SOC Publicador: AMER CHEMICAL SOC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.53%
Oxy-coal combustion is a viable technology, for new and existing coal-fired power plants, as it facilitates carbon capture and, thereby, can mitigate climate change. Pulverized coals of various ranks, biomass, and their blends were burned to assess the evolution of combustion effluent gases, such as NO(x), SO(2), and CO, under a variety of background gas compositions. The fuels were burned in an electrically heated laboratory drop-tube furnace in O(2)/N(2) and O(2)/CO(2) environments with oxygen mole fractions of 20%, 40%, 60%, 80%, and 100%, at a furnace temperature of 1400 K. The fuel mass flow rate was kept constant in most cases, and combustion was fuel-lean. Results showed that in the case of four coals studied, NO(x) emissions in O(2)/CO(2) environments were lower than those in O(2)/N(2) environments by amounts that ranged from 19 to 43% at the same oxygen concentration. In the case of bagasse and coal/bagasse blends, the corresponding NO(x) reductions ranged from 22 to 39%. NO(x) emissions were found to increase with increasing oxygen mole fraction until similar to 50% O(2) was reached; thereafter, they monotonically decreased with increasing oxygen concentration. NO(x) emissions from the various fuels burned did not clearly reflect their nitrogen content (0.2-1.4%)...

Um estudo da combustão de carvão mineral CE4500 em reator de leito fluidizado borbulhante; A study of CE4500 mineral coal combustion in a bubbling fluidized bed reator

Lindo Samaniego, Julio Edgardo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/08/2011 PT
Relevância na Pesquisa
36.51%
O carvão mineral apresenta-se como uma importante alternativa para geração termoelétrica no Brasil. Os carvões brasileiros, porém, são caracterizados por elevados teores de enxofre, e na sua combustão libera-se consideráveis de quantidades dióxido de enxofre. O processo de combustão em leito fluidizado apresenta-se particularmente adequado para a queima destes carvões, notadamente devido à possibilidade da utilização de absorventes calcários para remoção in loco do dióxido de enxofre produzido na combustão. Neste trabalho estudou-se a combustão em leito fluidizado atmosférico borbulhante de um carvão mineral beneficiado para uso termoelétrico denominado CE4500, procedente de Criciúma-SC. Para absorção de enxofre utilizou-se um calcário dolomítico procedente de Ipeúna-SP. Utilizou-se a planta piloto para combustão em leito fluidizado do Laboratório de Engenharia Térmica e Fluidos da EESC-USP, com câmara de combustão de 0,5 x 0,5 m de seção transversal e 3 m de altura. Ensaios foram realizados para diferentes velocidades de fluidização e relações (Ca+Mg)/S de alimentação. Concentrações de gases foram medidas ao longo da altura e da seção transversal do reator, permitindo verificar a homogeneidade do processo...

Mobilidade de As, Cd, Mo, Pb e Zn em colunas de latossolo argiloso com cinza de carvão e contaminação do solo; Mobility of As, Cd, Mo, Pb and Zn in clayey oxisol columns with coal fly ash and soil contamination

Silva, Juliana Cristina da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/02/2013 PT
Relevância na Pesquisa
36.54%
A contaminação do solo tem sido motivo de preocupação ambiental e de saúde pública, uma vez que o homem depende do seu uso para sobreviver. O resíduo de cinza de carvão, gerado da queima de carvão em usina termoelétrica, é uma das fontes contaminadoras do solo quando disposto de forma inadequada. Os elementos tóxicos da cinza de carvão, quando depositada sobre o solo e exposta à chuva, podem ser lixiviados da cinza para o solo. No solo estes elementos podem ser sorvidos, transportados para a água subterrânea e superficial ou absorvido pelas plantas, o que pode contaminar estas matrizes ambientais. O objetivo do estudo foi avaliar a mobilidade de As, Cd, Mo, Pb e Zn em colunas de Latossolo argiloso com cinza de carvão sobreposta ao solo e avaliar se a retenção destes elementos provoca a contaminação do solo. As colunas foram percoladas com uma solução ácida com pH 4,5 para simular água de chuva, por períodos de 168 e 336 dias. As amostras de cinza de carvão, solo e percolado das colunas foram analisadas quanto à concentração dos elementos e as características físicas, químicas e mineralógicas. O Pb não foi lixiviado da cinza de carvão, portanto, o solo e percolado do solo não foram contaminados por este elemento. Os elementos As...

Estudo de pré-viabilidade do acoplamento de um queimador de resíduos sólidos urbanos a uma usina de geração termelétrica a carvão; Pre-feasibility study of a municipal solid waste boiler coupling to a coal fired thermoelectric power plant

Leite, Pedro Amaral Brito
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
POR
Relevância na Pesquisa
36.48%
Este trabalho faz um estudo de pré-viabilidade do acoplamento de um queimador de resíduos sólidos urbanos (RSU) a uma usina de geração termelétrica a carvão. O acoplamento tem o objetivo de reduzir investimentos e os custos operacionais necessários à construção de uma usina de tratamento térmico de resíduos, pela utilização conjunta dos equipamentos e sistemas já instalados em uma usina a carvão. Foi feito um estudo de caso em uma usina a carvão no estado do Rio Grande do Sul. O estudo foi dividido em pré-viabilidade técnica e econômica. Na parte técnica é avaliado os balanços de massa e energia do vapor fornecido pelo queimador a RSU para a planta a carvão, e os equipamentos necessários para limpeza dos gases de combustão do RSU. A parte econômica é desenvolvida pelo fluxo de caixa dos investimentos, despesas e receitas necessários para o acoplamento. Foi proposto dois cenários para avaliação. A proposta não se mostrou economicamente viável apenas com receita proveniente da taxa de destinação final do RSU e dos créditos de carbono. Logo, foi proposta a queima de resíduos de serviço de saúde para o aumento da receita. O resultado mostrou que 3% de queima de RSS aproxima a TIR da TMA sem a contabilização das taxas de juros do financiamento. Portanto...

Dispersão geoquímica elementar e isotópica na atmosfera e no solo em área com atividade minerária e termoelétrica a carvão; Geochemical dispersion of elements and radionuclides in the atmosphere and soil of an area with mining and coal-fired thermoelectric power plant activities

Veridiana Polvani Campaner
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 15/02/2013 PT
Relevância na Pesquisa
36.58%
A identificação de anomalias antrópicas de elementos no solo e na atmosfera necessita do discernimento de possíveis mistura e dispersão de fontes antrópica e natural. Em área com atividade minerária e termoelétrica a carvão, no município de Figueira (PR), foram investigadas a distribuição multielementar (e.g. As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, U, Zn e radionuclídeos) em carvão, cinzas, rochas, solo e no material particulado atmosférico (partículas fina e grossa). Nos perfis de solo e no solo de superfície, a influência do carvão e cinzas resultou em assinaturas geoquímicas As/Zr, Cd/Zr, Hg/Zr, Mo/Zr, Pb/Zr, Sb/Zr, U/Zr e Zn/Zr elevadas, devido à mistura destas razões de origem natural no solo com àquelas do carvão e das cinzas. Os diques de diabásio regionais apresentaram assinaturas geoquímicas Co/Zr, Cr/Zr, Cu/Zr, Ni/Zr e Sc/Zr na configuração da paisagem pedológica da área de estudo, onde a maior influência foi de rochas sedimentares. A intensidade das anomalias antrópicas no solo de superfície foi maior para As, Cd e Mo, seguidos por Hg, Zn, Pb, Sb e U (ordem decrescente de intensidade). Estas anomalias mostraram uma distribuição espacial no solo de superfície condizente com a direção predominante dos ventos na área...

Coal and fuel burning effects on the atmosphere as mediated by the atmospheric electric field and galactic cosmic rays flux

Reis, A. Heitor; Serrano, Claudia
Fonte: Inderscience Publicador: Inderscience
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.53%
Abstract: Emissions into the atmosphere of Greenhouse Gases (GHGs) and particulate matter resulting from fossil fuel burning are considered to be the main anthropogenic forcing on the global climate. We show here that the external cyclic influences of cosmic origin that modulate the earth’s climate may either reinforce or mitigate the ‘local’ terrestrial forcings. Among the external influences is cosmic radiation, whose intensity shows a cyclic variation of 11 years, accompanying the 11-year cycle of solar activity. We put forward a mechanism to explain how the emission of particulate matter into the atmosphere might influence global lightning activity. With respect to global lightning activity, we show why, during the 11-year cycle, the influence of an increase in particulate matter concentration in the atmosphere may be negligible in some years, while it will be reinforced in other years, depending on the place of the years in the cycle. We also remark that the effect on global warming of fossil fuel burning is also modulated by the cosmic ray flux, whose influence is mediated by the variation that it promotes on the cloud cover.

Application of multivariate statistical analysis to superficial soils around a coal burning power plant

Godoy,Maria Luiza D. P; Godoy,José M; Roldão,Luis A; Conti,Luis F
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2004 EN
Relevância na Pesquisa
36.54%
The Thermoelectric Complex Jorge Lacerda (TCJL), located in the Santa Catarina State, Brazil, is the largest coal burning thermoelectric complex of Latin America and consists of seven power plants with a total capacity of 832 MWe. In order to estimate the contribution of the atmospheric releases from the TCJL to the elemental composition of surface soils around it, forty-five samples were collected at up to a distance of 8 km. Forty-two elements were determined by ICP-MS and ICP-AES after total acid dissolution. The technique of principal component analysis was employed to identify the major sources that contribute to surface soil composition. Additionally, a source apportioning using multiple regression on absolute principal component scores was performed in order to obtain quantitative information about the contribution of the different identified sources on the soil composition. Based on the results obtained, four sources were identified as the main contributors to the surface soil elemental composition. One of them was related to TCJL because it retains volatile elements enriched on fly ash and released from powerhouse stacks.

Current Status and Prevention Strategy for Coal-arsenic Poisoning in Guizhou, China

Li, Dasheng; An, Dong; Zhou, Yunsu; Liu, Jie; Waalkes, Michael P.
Fonte: International Centre for Diarrhoeal Disease Research, Bangladesh Publicador: International Centre for Diarrhoeal Disease Research, Bangladesh
Tipo: Artigo de Revista Científica
Publicado em /09/2006 EN
Relevância na Pesquisa
36.78%
Arsenic exposure from burning coal with high arsenic contents occurs in southwest Guizhou, China. Coal in this region contains extremely high concentrations of inorganic arsenic. Arsenic exposure from coal-burning is much higher than exposure from arsenic-contaminated water in other areas of China. The current status and prevention strategies for arsenic poisoning from burning high-arsenic coal in southwest Guizhou, China, is reported here. Over 3,000 arsenic-intoxicated patients were diagnosed based on skin lesions and urinary arsenic excretion. Non-cancerous toxicities and malignancies were much more common and severe in these patients than in other arsenic-affected populations around the world. The high incidence of cancer and arsenic-related mortality in this cohort is alarming. Chelation therapy was performed but the long-term therapeutic effects are not satisfactory. The best prevention strategy is to eliminate arsenic exposure. Funds from the Chinese Government are currently available to solve this arsenic exposure problem. Strategies include the installation of vented stoves, the use of marsh gas to replace coal, health education, the improvement of nutritional status, and the use of various therapies to treat arsenic-induced skin and liver diseases.

Financing Energy Efficiency : Lessons from Brazil, China, India, and Beyond

Taylor, Robert P.; Govindarajalu, Chandrasekar; Levin, Jeremy; Meyer, Anke S.; Ward, William A.
Fonte: Washington, DC : World Bank Publicador: Washington, DC : World Bank
EN_US
Relevância na Pesquisa
36.64%
Energy for heating, cooling, lighting, mechanical power, and various chemical processes is a fundamental requirement for both daily life and economic development. The negative impact on the environment of current energy systems is increasingly alarming, especially the global warming consequences of burning fossil fuels. The future requires change through the development and adoption of new supply technologies, through a successful search for new, less resource-intensive paths of economic development, and through adoption of energy. Greater energy efficiency is key for shifting country development paths toward lower-carbon economic growth. Especially in developing countries and transition economies, vast potential for energy savings opportunities remain unrealized even though current financial returns are strong. Activities included specialized technical assistance, training, and applied research covering the four primary areas of country interest: (a) development of commercial banking windows for energy efficiency; (b) support for developing energy service companies (ESCOs); (c) guarantee funds for energy efficiency investment financing; and (d) equity funding for ESCOs or energy efficiency projects. One clear message from the experience of the three country Energy Efficiency Project is the importance of establishing and maintaining practical...

Technology Assessment of Clean Coal Technologies for China : Volume 3. Environmental Compliance in the Energy Sector

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
Relevância na Pesquisa
46.59%
Analysts expect China to continue improving the efficiency of energy production and use, thereby decoupling the traditional relationship between gross domestic product (GDP) and energy consumption. Environmentally acceptable economic growth is closely linked with further improvements in the overall efficiency of energy use. Both of these goals will require a continued increase in the use of coal to produce electricity, along with a more deliberate and rapid transition from direct coal combustion to the use of electricity and other cleaner coal-based fuel sources, especially for cooking, space heating, and industrial furnaces. The opportunity for environmental improvement in conjunction with economic growth lies in the wise adoption of clean coal technologies (CCT) for both the electric power and non-power sectors. This report presents CCT options for the power sector that can help China achieve these twin goals. The CCT options are: 1) air pollution controls for particulates, sulphur dioxide, and nitrous oxide; and 2) advanced electricity generation technologies--supercritical pulverized-coal boilers...

A new rheometer for direct measurement of the flow properties of coal ash at high temperatures

Tonmukayakul, N.; Nguyen, Q.
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: Artigo de Revista Científica
Publicado em //2002 EN
Relevância na Pesquisa
36.51%
Development of more effective technologies of utilising low rank coals for power generation has been driven by a demand for higher efficiency, low capital costs and minimal environmental impacts. Fluidised bed systems are regarded as one of the more promising alternative technologies for power generation to overcome the disadvantage of the existing pulverised coal burning power generation plants for low rank coals. However, ash deposition and bed agglomeration are potential problems in fluidised bed processing of coals with high alkali and sulphur contents. In order to gain a better understanding of the mechanism of agglomeration in fluidised beds, a good knowledge of the rheological behaviour of coal ash deposits at high temperatures and under the processing conditions is necessary. Rheological characterisation of materials at high temperatures is difficult due to lack of standard instruments and reliable measurement techniques. We have recently developed a rheometer that has the capability of measuring the rheological properties of coal ash slag over a wide range of temperatures from 600 to 1300°C and under different processing atmospheres. In this paper the features of this unique instrument are described and the experimental technique developed for flow property measurement is outlined. Some typical measured rheological properties of coal ashes from different Australian low-rank coals are presented and discussed to illustrate the potential applicability of the rheometer for high-temperature rheological characterisation. Furthermore...

Studies of the Release of Sodium from Pulverised Coal in a Flat Flame Burner

Syred, N.; van Eyk, P.; Chong, W.; Alwahabi, Z.; Nathan, G.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Conference paper
Publicado em //2004 EN
Relevância na Pesquisa
36.73%
This paper investigates the problem of the rate of release of alkalis from coal/coal blends as they are burnt in Utility Boilers with the aim of evolving better models of the effect of given fuel blends on slagging and fouling in real boiler situations. Although numerous slagging and fouling indices have been evolved over many years to describe the behaviour of coals in given boiler situations they often fail to give the required results and prove to be of little use when co-firing blends of coal with biomass materials. In this work we have constructed a natural gas flat flame burner with associated furnace and viewing ports so we can use a PLIF system to look at the evolution of sodium from burning coal/coal blend particles and relate this to the condition of the ash in the burning coal particle as the ash particle reaches the region of the superheater tubes in a boiler. By appropriate adjustment of the air fuel ratio we can produce temperature/residence time distributions downstream of the flat flame burner and in the furnace section which closely parallel those found in Utility Boilers. Pulverised coal particles as produced for boiler firing are sieved into two fractions, those in the size range 67 to 37 microns and above 67 microns (virtually no residue was found below 37 microns). This was to ensure that the finer fraction had a narrow size distribution...

Simultaneous measurements of the release of atomic sodium, particle diameter and particle temperature for a single burning coal particle

van Eyk, P.; Ashman, P.; Alwahabi, Z.; Nathan, G.
Fonte: The Combustion Institute Publicador: The Combustion Institute
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
46.7%
The temporal history of the release of volatile alkali species during coal combustion is a significant, but poorly understood factor in the fouling and corrosion of heat transfer surfaces within industrial coal-fired boilers. We present new results of the simultaneous measurement of particle temperature, particle size and the atomic sodium concentration in the plume of a burning coal particle. During the char phase, the sodium concentration in the plume was found to be linearly dependent on the inverse of particle diameter, but during the ash phase the sodium concentration was found to decay exponentially with decreasing particle temperature. The centreline decay of Na within the plume above the burning particle consists of one region controlled by a first order chemical reaction and a second region controlled by diffusion; P.J. van Eyk, P.J. Ashman, Z.T. Alwahabi and G.J. Nathan; Copyright © 2009 Elsevier B.V. All rights reserved

Quantitative in-situ measurements of sodium release during the combustion of single coal particles using planar laser induced fluorescence.

van Eyk, Philip Joseph
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
46.79%
The release of sodium from low rank coal during combustion is known to be an important factor in the phenomena of fouling and corrosion in industrial boilers. Although much is known about the gas phase chemistry of sodium compounds, and the likely sequence of events that lead to fouling and corrosion, very little fundamental work has been undertaken on the release of sodium from the coal particle as it is combusted. The principal objective of this study was to perform detailed quantitative measurements and mathematical modelling of sodium release during combustion of single brown coal particles. Planar Laser Induced Fluorescence (PLIF) was applied for the in-situ measurement of the atomic sodium concentration field in the plume of single Loy Yang brown coal particles. Laser absorption measurements at the sodium D1 line (589.59 nm) were utilised to calibrate PLIF measurements of atomic sodium in a purpose designed flat flame environment. Detailed measurements of atomic sodium in the plume of single combusting brown coal particles of varying amounts and forms of sodium and of varying particle sizes were then undertaken. A run-of-mine Loy Yang brown coal sample and two samples that were processed using Mechanical/Thermal Expression (MTE)...

Sodium and potassium released from burning particles of brown coal and pine wood in a laminar premixed methane flame using quantitative laser-induced breakdown spectroscopy

Hsu, L.J.; Alwahabi, Z.; Nathan, G.; Li, Y.; Li, Z.; Alden, M.
Fonte: Soc Applied Spectroscopy Publicador: Soc Applied Spectroscopy
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
46.88%
A quantitative point measurement of total sodium ([Na]total) and potassium ([K]total) in the plume of a burning particle of Australian Loy Yang brown coal (23 ± 3 mg) and of pine wood pellets (63 ± 3 mg) was performed using laser-induced breakdown spectroscopy (LIBS) in a laminar premixed methane flame at equivalence ratios ( U ) of 1.149 and 1.336. Calibration was performed using atomic sodium or potassium generated by evaporation of droplets of sodium sulfite (Na2SO3) or potassium sulfate (K2SO4) solutions seeded into the flame. The calibration compensated for the absorption by atomic alkalis in the seeded flame, which is significant at high concentrations of solution. This allowed quantitative measurements of sodium (Na) and potassium (K) released into the flame during the three phases of combustion, namely devolatilization, char, and ash cooking. The [Na]total in the plume released from the combustion of pine wood pellets during the devolatilization was found to reach up to 13 ppm. The maximum concentration of total sodium ([Na]maxMtotal) and potassium ([K]maxtotal) released during the char phase of burning coal particles for φ = 1.149 was found to be 9.27 and 5.90 ppm, respectively. The [Na]maxtotal and [K]maxtotal released during the char phase of burning wood particles for φ = 1.149 was found to be 15.1 and 45.3 ppm...

China : Air Pollution and Acid Rain Control - The Case of Shijiazhuang and the Changsha Triangle Area

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: ESMAP Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
36.48%
This study, and the associated technical assistance project, has three main objectives. The first is to help localities in China address several questions related to the planning, and implementation of SO2 emissions, and acid rain control: What are the environmental consequences, specifically for localities of different pollution control strategies, in terms of the impacts on human health, agricultural productivity, and other sectors and activities? What are the relative costs of different sulfur emission reduction plans? Will the proposed strategies enable localities to meet the environmental targets set by the central government? The second objective is to assist with capacity building, and training in China. to enable cities and regions to carry out environmental, and economic analyses of sulfur emission impacts, and control programs. The third objective is to provide a forum for discussion with the central government, primarily the State Environmental Protection Administration (SEPA), on the results of the case studies...

Impacts of Mountaintop Removal Coal Mining on the Mud River, West Virginia: Selenium Accumulation, Trophic Transfer, and Toxicity in Fish

Arnold, Mariah Christine
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2014
Relevância na Pesquisa
36.48%

Selenium (Se) is a micronutrient necessary for the function of a variety of important enzymes; Se also exhibits a narrow range in concentrations between essentiality and toxicity. Oviparous vertebrates such as birds and fish are especially sensitive to Se toxicity, which causes reproductive impairment and defects in embryo development. Selenium occurs naturally in the Earth's crust, but it can be mobilized by a variety of anthropogenic activities, including agricultural practices, coal burning, and mining.

Mountaintop removal/valley fill (MTR/VF) coal mining is a form of surface mining found throughout central Appalachia in the United States that involves blasting off the tops of mountains to access underlying coal seams. Spoil rock from the mountain is placed into adjacent valleys, forming valley fills, which bury stream headwaters and negatively impact surface water quality. This research focused on the biological impacts of Se leached from MTR/VF coal mining operations located around the Mud River, West Virginia.

In order to assess the status of Se in a lotic (flowing) system such as the Mud River, surface water, insects, and fish samples including creek chub (Semotilus atromaculatus) and green sunfish (Lepomis cyanellus) were collected from a mining impacted site as well as from a reference site not impacted by mining. Analysis of samples from the mined site showed increased conductivity and Se in the surface waters compared to the reference site in addition to increased concentrations of Se in insects and fish. Histological analysis of mined site fish gills showed a lack of normal parasites...

Book review: The silent epidemic: coal and the hidden threat to health

Harvey, Ross
Fonte: London School of Economics and Political Science Publicador: London School of Economics and Political Science
Tipo: Website; NonPeerReviewed Formato: application/pdf
Publicado em 07/02/2013 EN; EN
Relevância na Pesquisa
36.48%
We will not find “exposure to burning coal” listed as the cause of death on a single death certificate, but tens of thousands of deaths from asthma, lung cancer, heart attacks, strokes, and other illnesses are linked to coal-derived pollution. As politicians and advertising campaigns extol the virtues of “clean coal”, the dirty secret is that coal kills, argues Alan Lockwood in The Silent Epidemic. Lockwood addresses the big issues of global warming, health economics, and their policy implications, leaving Ross Harvey to recommend the book as a reference tool for answering critical questions of how to minimise the social costs of coal.

The estimation of greenhouse gas emissions from South African surface and abandoned coal mines

Cook,A.P.; Lloyd,P.J.D.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
46.65%
Gas samples were taken from a wide range of target areas on dumps arising from coal mining activities. Some of the dumps had largely burned out, some were still burning, some were in the process of rehabilitation, and on others rehabilitation was essentially complete. It was found that rehabilitation was very effective in reducing emissions to tolerable levels. Even incomplete rehabilitation reduced the CO2 emissions to less than about 1 kg/m²/a, whereas some unrehabil-itated areas showed emissions of over 100 kg/m²/a. Some areas where there was active combustion taking place were also sampled, and they showed as much as 7 000 kg/m²/a, but the areas concerned were very small and their total contribution accordingly low. Analyses were also made for SOx, NOx, NH3, and CH4, but these were generally (and unexpectedly) at very low levels. The mines sampled represented 53 per cent of all surface coal mining activity. Accordingly the estimated total emissions were scaled up, to arrive at estimates of 1 950 000 ± 350 000 t/a CO2, 2040 ± 580 t/a SOx, 306 ± 85t/a NOx, and 31 ± 9 t/a NH3 for all surface mines. Methane was detected only from burning coal, and due to the difficulty in sampling, no reliable estimate could be made of these methane emissions.

Achievable combustion efficiency with Alstom CFB boilers for burning discarded coal

Gauvillé,P; Foucher,J.-C.; Moreau,D
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
46.94%
The key driver for choosing a circulating fluidized bed (CFB) boiler is the ability to burn a wide range of fuels with highly efficient combustion while meeting low emission requirements. Reduced sorbent and water consumption compared with pulverized coal (PC) plants and the ability to deal with corrosive fuel constituents while still meeting local regulations make a CFB boiler-based power plant particularly attractive. CFB-based power generation is particularly relevant in coal mining areas. During mining, a portion of the roof and floor material may be extracted along with the coal seam in order to create adequate working height for the equipment and miners. Therefore, run-of-mine coal which comes directly from the mine contains impurities. The raw coal can undergo a washing or screening process in order to improve its quality by reducing the ash content in the fuel in order to sell it on the export market or to comply with domestic customer requirements. The coal discarded from the washing process usually has a high ash content and difficult mechanical properties resulting from the initial properties, the mining, and the coal cleaning processes. It can contain a large volume of stones or can be very fine as a result of the washing treatment. To create value from burning this discarded coal...