Coal, sustainability

For utihties, two types of storage are used. A small amount of coal in storage meets daily needs and is continually turned over. This coal is loaded into storage bins or bunkers. However, long-term reserves are carefully piled and left undisturbed except as necessary to sustain production. 

Vei y small solid fuel particles such as sawdust, agricultural grains, or coal dust can sustain flames when they are suspended in air. In fact, very serious fires have occurred in grain storage towers and coal mines because of the flammability of suspended dusts. The combustion of the individual particles follows the usual pattern of solid particle burning— devolatization and char burning. The combustion of the whole cloud of particles is similar to spray combustion and its characteristics depend on the nature of the fuel, size of the particles, and the number of particles in a given volume. 

Can hydrogen be produced sustainably Over the next few decades, and probably well into the twenty-first centui y, fossil sources such as natural gas or coal may offer the lowest costs in many locations, with small contributions from electrolysis powered by low-cost hydropower. 

Coal is the least expensive and most sustainable fossil fuel energy source (world reserves of 1.2 to 1.8... 

For abiotic stock resources, the resource value is set as equal to the production and environmental cost for a sustainable alternative. For fossil oil, gas and coal, these alternatives are rapeseed oil, biogas and charcoal, respectively. For metal (metal ores), the production and environmental costs to upgrade low-quality ores (sustainable supplies), such as silicate minerals, to a quality similar to present day ores, using a bioenergy-driven process (near-sustainable process), is used as the resource value. 

Stiegel, G.J. and Ramezan, M., Hydrogen from coal gasification, An economical pathway to a sustainable energy future, Int.. Coal Geol., 65,173, 2006. 

EC (European Commission) (2007c). Sustainable Power Generation from Fossil Fuels Aiming for Near-Zero Emissions from Coal after 2020. Communication from the Commission to the Council and the European Parliament, COM(2007), 843 final. 

The alternative fuels and drive systems available only seem to be viable on the mass market, if the oil price stays above 60 to 70 /bbl for a sustained period. Oil prices peaked above 140 /bbl in summer 2008 and many experts believe that stable oil prices over 100 /bbl could be reached in the next one or two decades. The higher the market prices of fossil fuels, the more competitive low-carbon alternatives will become The principal choice here is between biofuels, electricity and hydrogen, provided that they are produced either from low/zero-carbon feedstock or that the C02 generated during their production is captured and stored. But higher priced conventional oil resources, on the other hand, can also be replaced by high-carbon alternatives such as oil sands, oil shale or synthetic fuels from coal and gas. 

However, the question whether the combustion of oxidised or weathered pulverised coal would maintain a self-sustaining flame in a full-size industrial boiler at maximum load cannot be addressed within the present study. The inhibition of volatile matter release, due to the promotion of char condensation reactions during coal pyrolysis, suggests that this may not be the case, a point pertaining especially to the more severely oxidised coals (i.e. 373 K for 112 days). Clearly there is need for ture work within this area of pulverised coal combustion. 

Research Centre for Coal in Sustainable Development www.ccsd.biz Cooperative... 

Robl, T. L. Groppo, J. G. 2002. The production of superpozzolan from coal fired utility ash ponds. In Dhir, R. K., Dyer, T. D. Halliday, J. E. (eds) Sustainable Concrete Construction. Thomas Telford Publishing, London, England, 2002. 

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