Booster air heater for high moisture fuels

摘要

A system and method for drying pulverized high moisture fuel for use in a selective catalytic reduction system equipped combustion system is provided. The combustion system includes a mill for pulverizing fuel, an air heater, a booster air heater and a fuel duct for feeding dried pulverized fuel to a combustion furnace.

主权项

1. A method for drying pulverized high moisture fuel used to fuel a combustion system equipped with a selective catalytic reduction system; the method comprising:
pulverizing, in a mill a high moisture fuel to produce a moist pulverized fuel; heating primary air in an air heater using a first flue gas stream, whereby the first flue gas stream heats the primary air to an increased temperature; heating the primary air from the air heater using a second flue gas stream being a higher temperature than the first flue gas stream, whereby the second flue gas stream further heats the heated primary air from the air heater in a booster air heater to a higher temperature, the second flue gas stream being, a portion of the flue gas exiting an interior chamber of the combustion system prior to passing through a heat exchanger; drying the moist pulverized fuel in a mill using the higher temperature primary air from the booster air heater to produce a dry pulverized fuel; and feeding the dry pulverized fuel from the mill to a combustion furnace.