FLUIDIZED BED COMBUSTION SYSTEM AND METHOD HAVING A MULTICOMPARTMENT VARIABLE DUTY RECYCLE HEAT EXCHANGER

摘要

A fluidized bed combustion system and method in which a recycle heat exchanger is located adjacent the furnace section of the recycle heat exchanger. Heat exchange surfaces are provided in a compartment of the recycle heat exchanger for removing heat from the solids, and a bypass compartment is provided through which the solids directly pass to the furnace during start- up and low load conditions. The flow of solids between compartments is selectively controlled and an L-valve connects one of the compartments to the furnace section. Air is passed into the L-valve to promote the flow of the separated material s from the latter compartment to the furnace. The flow rate of the air is modulated to vary the duty of the recycle heat exchanger.