Showing papers on "Coal published in 2001"

Environmental Impact of Coal Mining on Water Regime and Its Management

Abstract: Coal mining is one of the core industries that contribute to the economic development of a country but deteriorate theenvironment. Being the primary source of energy coal has becomeessential to meet the energy demand of a country. It isexcavated by both opencast and underground mining methods andaffects the environment, especially water resources, by discharginghuge amounts of mine water. The mine water may be acidic orneutral depending upon the pyrite content in the coal asinorganic impurities. Acid mine drainage occurs in those mines in which sulphur content is found in the range of 1–5% in the form of Pyrite (FeS2). It degrades the water qualityof the region in terms of lowering the pH of the surrounding water resources and increasing the level of total suspended solids, total dissolved solids and some heavy metals. In non acidic mines, water quality shows high hardness, TSS and bacterial contaminants. The leachate water from overburden dump are found enriched in metal concentration especially Fe, Cu, Mn and Ni except in one of the clayey dumps. High values ofhardness of mine water reduces it's utility in domestic purposes.The article illustrates the quality of acidic and non acidic minewater and leachate characteristics of opencast coal mining OBdumps. Pollutants such as TSS, TDS, oil and grease and heavy metalare found in the coal mining waste effluents. Management ofthese liquid waste at the primary level and secondary level havealso been suggested to control the pollution level at the source.

In situ thermal processing of a coal formation using a controlled heating rate

Abstract: An oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a desired temperature. A heating rate for a selected volume of the formation may be controlled by altering an amount of heating energy per day that is provided to the selected volume.

Progress in Thermochemical Biomass Conversion

Abstract: Combustion: Co-combustion of coal and biomass wastes in fluidised bed Development of catalytic wood fired boiler The mathematical modelling of biomass pyrolysis in a fixed bed and experimental verification Operating parameters for the circulating fluidised bed (CFB) processing of biomass Combustion properties of a fuel bed - Experimental and modelling study Summary of recent parametric studies of small-scale domestic biomass combustion Combustion processes in a biomass fuel bed - Experimental results of the influence of airflow and of particle size and density Influence of the ash composition in slagging and defluidisation in a biomass fired commercial CFB boiler A new type of a boiler plant for dry and wet biofuel Gasification: Modern technologies of biomass conversion Redox process for the production of clean hydrogen from biomass Dynamic Modelling of Char Gasification in a Fixed-Bed A two stage pyrolysis/gasification process for herbaceous waste biomass from agriculture Fundamental fluid-dynamic investigations in a scaled cold model for biomass-steam gasification Biomass Power Generation: Sugar Cane Bagasse and Trash Biomass and waste to energy conversion in the Netherlands by means of (in) direct co-combustion: Status, projects and future applications in the Dutch utility sector Gasification study of biomass mixed with plastic wastes The development of methanol synthesis with biomass gasification Final report: Varnamo demonstration programme Design of a moving bed granular filter for biomass gasification Pyrolysis: Bagasse pyrolysis in a wire mesh reactor BCO/Diesel oil emulsification: Main achievements of the emulsification process and preliminary results of tests on diesel engine Overview of fast pyrolysis Production of hydrogen from biomass-derived liquids Levoglucosenone - A product of catalytic fast pyrolysis of cellulose Pyrolysis and gasification of black liquors from alkaline pulping of straw in a fixed bed reactor Thermal efficiency of the HTU process for biomass liquefaction Low-temperature pyrolysis as a possible technique for the disposal of CCA treated wood waste Mathematical modelling of the flash-pyrolysis process for wood particles Flash pyrolysis of biomass in a conical spouted bed. Kinetic study in the 400-500C range Scale up effect on plastics waste pyrolysis Research on the rotating cone reactor for sawdust flash pyrolysis Thermal desorption technology: Low temperature carbonisation of the biomass for manufacturing of activated carbon Scaling-up and operation of a flash-pyrolysis system for bio-oil production and applications on basis of the rotating cone technology Systems: Utilisation of bagasse residues in power production Barriers for the introduction of biomass in the Netherlands Assessment of the techno-economic viability of a bioelectricity demonstration plant in Spain Innovative components for decentralised combined heat and power generation from biomass gasification A role of bioenergy utilization technologies considering bioenergy supply potential and energy systems using a global energy and land use model

Utilization of zeolites synthesized from coal fly ash for the purification of acid mine waters.

Abstract: Two pilot plant products containing 65 and 45% NaP1 zeolite were obtained from two Spanish coal fly ashes (Narcea and Teruel Power Station, respectively). The zeolitic product obtained showed a cation exchange capacity (CEC) of 2.7 and 2.0 mequiv/g, respectively. Decontamination tests of three acid mine waters from southwestern Spain were carried out using the zeolite derived from fly ash and commercial synthetic zeolite. The results demonstrate that the zeolitic material could be employed for heavy metal uptake in the water purification process. Doses of 5-30 g of zeolite/L have been applied according on the zeolite species and the heavy metal levels. Moreover, the application of zeolites increases the pH. This causes metal-bearing solid phases to precipitate and enhances the efficiency of the decontamination process.

A life cycle assessment of biomass cofiring in a coal-fired power plant

Abstract: The generation of electricity, and the consumption of energy in general, often result in adverse effects on the environment. Coal-fired power plants generate over half of the electricity used in the U.S., and therefore play a significant role in any discussion of energy and the environment. By cofiring biomass, currently operating coal plants have an opportunity to reduce the impact they have, but to what degree, and with what trade-offs? A life cycle assessment has been conducted on a coal-fired power system that cofires wood residue. The assessment was conducted in a cradle-to-grave manner to cover all processes necessary for the operation of the power plant, including raw material extraction, feed preparation, transportation, and waste disposal and recycling. Cofiring was found to significantly reduce the environmental footprint of the average coal-fired power plant. At rates of 5% and 15% by heat input, cofiring reduces greenhouse gas emissions on a CO2-equivalent basis by 5.4% and 18.2%, respectively. Emissions of SO2, NOx, non-methane hydrocarbons, particulates, and carbon monoxide are also reduced with cofiring. Additionally, total system energy consumption is lowered by 3.5% and 12.4% for the 5% and 15% cofiring cases, respectively. Finally, resource consumption and solid waste generation were found to be much less for systems that cofire.

Estimation of Hydrogen Bond Distribution in Coal through the Analysis of OH Stretching Bands in Diffuse Reflectance Infrared Spectrum Measured by in-Situ Technique

Abstract: A new method was presented to estimate the strength distribution of hydrogen bonds in coal. The hydrogen bonds include the coal intramolecule hydrogen bonds and coal−water hydrogen bonds formed by hydroxyls in coal. The method analyzes the FTIR spectrum ranging from 2400 to 3700 cm-1 obtained using the in-situ diffuse reflectance IR Fourier transform (DRIFT) technique with neat, undiluted, coal samples. The FTIR spectra during the heat-up of eight coals (seven Argonne premium coals and an Australian brown coal), an ion-exchange resin, and a lignin were measured every 20 °C from room temperature to 300 °C. Each spectrum was divided into six hydrogen-bonded absorption bands by a curve-resolving method, then the amount of hydroxyls contributing to each hydrogen bond was estimated by Beer's law by using different absorptivity for each band. The strength of each hydrogen bond was estimated using a relation presented by Drago et al. that is known as one of the “linear enthalpy−spectroscopic shift relations”. Us...

Control of pollutants in flue gases and fuel gases

Abstract: Funding from the Nordic Energy Research Programme and from Helsinki University of Technology allowed for the preparation of this e-book, accompanied by overhead sheets as presented during the lectures. All material can be downloaded as pdf documents from the internet-address http://www.hut.fi/-rzeveho//gasbook, hence the qualification e- book Updates will be produced chapter-by-chapter in the future. Objectives and scope. Textbooks on this subject are, in general, limited to what can be called 'conventional' flue gas cleaning for conventional pulverised coal combustion processes, i.e. wet flue gas desulphurisation (FGD), bag filters and electrostatic precipitators for flyash and selective catalytic reduction (SCR) for NO{sub x} control. Other books address waste incineration within a discussion on waste management. The scope of this material we tried to make more up-to-date and therefore wider than these texts. Apart from pollutant control the formation of the pollutants is briefly addressed, which often provides the key to abatement methods as an alternative to control methods. Secondly, more species are addressed such HS in addition to SO{sub 2}; N{sub 2}0, HCN and NH{sub 3} in addition to NO{sub x}; alkali metals and trace elements such as mercury, halogenic compounds such as HO and dioxines and furanes; and volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Also greenhouse gases, mainly CO{sub 2}, and ozone-depleting gases, such as CFCs, are briefly discussed. The motivation for this was to cover flue gases from combustion as well as fuel gases from gasification processes, using various types of furnaces and boilers, and to extend the range of chemical compounds to those found in the product gases in waste incineration and energy-from-waste processes. Finally, not only 'cold' gas cleaning but also 'hot' gas cleaning is addressed. All this in an attempt to cover the wide spectrum of pollutants found in gas streams in modern thermal power generation processes, being based on combustion or gasification, with a fossil fuel, biomass or waste-derived fuel as input. Recovery boilers for black liquor are, however, not specifically- dealt with. For preparing the material the most important sources were the reports from LEA Coal Research in London, UK; Chapters 9, 10 and 11 of the Finnish textbook 'Poltto ja palaminen', and the articles, papers and theses (co-)produced by the authors themselves since the 1990s. (orig.)

Mesoporous materials prepared using coal fly ash as the silicon and aluminium source

Abstract: Coal fly ash was converted into two types of porous materials, MCM-41 and SBA-15 (both of hexagonal structure), using the supernatant of the fly ash. It was found that most of the Si and Al components in the fly ash could be effectively transformed into mesoporous materials, depending on the hydrothermal conditions, and that fusion is essential. Investigation by 29Si and 27Al MAS NMR demonstrated that fusion plays an important role in enhancing the hydrothermal conditions for synthesis of these materials. A high concentration of Na ions in the supernatant of the fused fly ash was not found to be critical in the formation of Al-MCM-41 when prepared under controlled pH conditions. Pyridine adsorption experiments on Al-MCM-41 prepared from coal fly ash revealed the presence of Bronsted and Lewis acid sites. It was also found that the catalytic activity in the cumene cracking reaction is linked only to the accessible aluminium, and not to the total incorporated aluminium present in the Al-MCM-41.