Coal-fired power plants have traditionally operated with stack temperatures in the 300℉ range to minimize fouling and corrosion problems due to suifuric acid condensation and to provide a buoyancy force to assist in the transport of flue gas up the stack. However, as an alternative, there would be significant benefits to cooling the flue gas to temperatures below the water vapor and acid dew points. Among other benefits, the condensed water vapor would provide a source of water for use in power plant cooling; recovered latent and sensible heat could be used to reduce unit heat rate; and the availability of low temperature flue gas with reduced acid and water vapor content would reduce the costs of capturing CO_2 in back-end CO_2 scrubbers. This paper describes analyses carried out to estimate potential water vapor recovery rates and heat rate reductions which would result from separating water vapor from boiler flue gas in condensing heat exchangers.
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