|ICESP X CONFERENCE PAPER ABSTRACTS 8A SERIES
Held in Cairns,
Conference on Electrostatic Precipitation (ICESP)
is the official conference of the International Society for Electrostatic
PERFORMANCE IMPROVEMENT OF ELECTROSTATIC PRECIPITATOR: SOME EXPERIMENTAL STUDIES
Emissions standards are becoming more stringer, as a result new retrofit/technique are beingapplied in the existing power plant in India. Electrostatic Precipitators (ESP) are used to control fly ash emitting from the boilers of the power plants. The coal burned in power plants in India to generate the power are characterized by low calorific value (3500-4500) Kcal/Kg., and high ash content (35-45) %. Thus compared to U.S. and European coals, Indian coal generate about 6 to 7 times more ash for collection for similar electricity generation. Besides, low sulfur content (<0.5), results in the resistivity of fly ash being 100-1000 times higher than that generated elsewhere. Thus ESPs in India, despite being much larger, have lower collection efficiencies than the ESPs in U.S/Europe. In this paper we discuss some methods which are being applied in different power plants in India to improve the collection efficiencies of ESP.
The methods, which have met with success, are (a) Pulse charging of ESP unit, (b) Flue gasconditioning by water fogging and ammonia, and (c) coal ash conditioning with sodium salt before feeding to boiler. In some case additional ESP was put in series with the existing one thereby, increasing the total collection area. The paper describes the experiments and analyses the results obtained.
LENA LILLIEBLAD AND CHRISTER MAURITZSON
Electrostatic precipitators (ESP's) are commonly used for collection of particles in power plantsand industrial applications. There are many ESP's around the world not meeting today's requirements due to aging, process changes and more stringent regulations for emission limits. Before ESP performance improvements can be considered, measures must be taken to ensure that the equipment is mechanically sound. Once this is accomplished there are various upgrade technologies available to improve the ESP performance. In order to choose the most appropriate upgrading technology it is necessary to have a good knowledge about the site-specific conditions.
Measures can be taken to:
·Avoid or reduce the effect of high resistivity dust
· Reduce re-entrainment of dust caused by rapping or high gas velocity
· Change the mechanical ESP design by replacing internals and/ or rapping system
· Upgrade the ESP energy supply and control systems
· Optimize gas distribution and reduce sneakage
· Increase the ESP size
· Change the particle size distribution with agglomeration technologies
In this paper different upgrading techniques are described and compared both from a technical andeconomical point of view. A modern ESP control system is often a cost-effective method with a significant potential to reduce both emissions and power consumption especially at high resistivity dust conditions.
Exchange of old transformer/ rectifiers (T/R's) to high-frequency power converters have beensuccessful in reducing the effect of corona quenching and allowing a higher T/R power input when severe space charge conditions prevails at high dust loads. Significant reductions in emissions have been observed.
Last updated: May 10, 2009.
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