Abstract
Ultra Super Critical (USC) technology, whose steam temperature is over 593℃, has been developed under government subsidization and applied to many power plants in Japan since early 1990. IHI delivered first USC boiler in Japan in 1993 and completed nine units in total by now, including one with steam temperature 620℃. Furthermore two units are under construction. Coal fired boilers built in the 1960's and 1970's are overdue for replacement due to aging and to meet latest environmental requirement. Customers of those boilers have strong intention to upgrade unit capacity and plant efficiency, when replacing old ones within the existing limited area. To meet such demand, IHI developed new type of tower boiler with USC technology. This paper introduces design concept and latest experience of IHI tower type USC boilers in Japan and Germany.
