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Co-firing also decreased the load on the pulverizers, potentially improving the sieve analysis of the coal and improving NOX emissions through that approach as well. NOX emissions were not reduced at Willow Island Generating Station as a function of co-firing.
The Allegheny co-firing demonstrations were successful. They demonstrated that co-firing in cyclone and T-fired boilers could be deployed commercially with certain operational benefits, few operational penalties and with environmental improvements. The success of any such deployment, however, depends on the plant-specific economics, including differential fuel costs, the monetized value placed on SO2 and NOX emissions, and the consequences for co-firing on coal procurement.
New advances in emerging technologies: Waterwall corrosion monitor successfully used for supercritical cracking at Luminant Martin Lake and at Pennsylvania Power and Light (PPL) Brunner Island
The on-line monitoring of corrosion will be a major advance in the tracking of early failures of boiler tubes, and it will be a useful supporting approach to regular ultrasonic inspections of the furnace walls. Single-point electrochemical sensors can provide qualitative and quantitative descriptions of high-temperature corrosion conditions in the radiant section of utility boilers. But this does not provide broad, on-line, continuous data.
Rowan Technologies Ltd., a UK-based company, developed a range of scanner systems for monitoring corrosion/erosion and thermal behavior for small or large areas of the plant. Data can be presented in the form of multi-dimensional plots. The systems are non-intrusive, using electrodes connected externally to the plant, and are maintenance-free at the monitoring location, allowing lifetime monitoring in potentially inaccessible areas. This scanning technology, which uses an ingenious scheme of circulating electric currents through the furnace wall, has been tested at the Drax Power Station, the largest coal-fired station in Western Europe with six 660 MW units. It also was successfully tested at two plants in the U.S.