OCR Text |
Show boilers and process combustors it is clear that the non-utility development of coal-liquid mixture technology will be much more difficult. A start has been made in this direction with the development of the ceramic atomizer by Scotia Liquicoal, and it is anticipated that this burner will require industrial demonstration in boilers, kilns, both of which are drastically different in their burner, flame shape and heat transfer requirements. However, whilst much scale-up information will be generated as larger utility demonstrations proceed, the small Chatham units are typical of many industrial boilers which may directly utilize the operating experience gained there. Consequently, at the conclusion of the coal-water mixture program in eastern Canada, some of the industrial sector, particularly large kilns and boilers, may convert to coal-water mixtures as fuels. However, smaller units, which may not be large enough to accommodate this slower burning unreactive fuel, may be compelled to use coal-oil or coal-oil-water mixtures. There will be need for significantly more R and D support for the penetration of coal-liquid mixtures into the industrial, marine and diesel markets. Following the Chatham demonstrations, scale-up is the next obvious step. Design of burners for front-wall or tangentially fired boilers in the 50 to 150 MW(e) range is planned as a third phase of the coal-water mixture program. A start has been made on a generalized derating study which uses modelling techniques to predict boiler performance when boilers designed for oil are fired with coal-water mixtures. A priori reasoning cannot predict specific derating effects because there is insufficient experience connecting the formation of ash from coal-water flames burning finely ground coal in an atomized spray to slagging or erosive effects on boiler tube surfaces. When more information concerning ash properties and ash formation is available from the current work, the program will go on to include specific application studies to 100 and 150 MW(e) oil-fired boilers in NOva Scotia which will predict the minimum overall cost, by balancing the costs of boiler derating against those of fuel beneficiation. 12-18 |