OXY-FIRED BOILER UNIT AND METHOD OF OPERATING THE SAME

摘要

An oxy-combustion boiler unit is disclosed which includes a furnace for combusting fuel and for emitting flue gas resulting from combustion. The furnace has first, second and third combustion zones, and an air separation unit for separating oxygen gas from air and providing a first portion of the separated oxygen to a first oxidant flow, a second portion to a second oxidant flow, and a third portion of the separated oxygen gas to the first, second, and third zones of the furnace. A controller can cause the separated oxygen gas to be distributed so that the first and second oxygen flows have a desired oxygen content, and so that the first, second, and third zones of the furnace receive a desired amount of oxygen based on a combustion zone stoichiometry control.

主权项

1. An oxy-combustion boiler unit, comprising:
a furnace for combusting fuel and for emitting flue gas resulting from combustion, the furnace having a first combustion zone, a second combustion zone and a third combustion zone; an air separation unit for receiving air and for separating oxygen gas from the air; at least one conduit for mixing a first portion of the separated oxygen gas with a first flow of the flue gas to form a first oxidant flow having a first predetermined content of oxygen therein, for mixing a second portion of the separated oxygen gas with a second flow of the flue gas to form a second oxidant flow having a second predetermined content of oxygen therein, and for directing a third portion of the separated oxygen gas to the first, second and third combustion zones of the furnace for combustion of the fuel, wherein the conduit directs the first oxidant flow to the first combustion zone of the furnace and directs the second oxidant flow to the first, second and third combustion zones of the furnace; and a controller for combustion zone stoichiometry control of the furnace by causing a first amount of the third portion of the separated oxygen gas to be sent to the first combustion zone, a second amount of the third portion of the separated oxygen gas to be sent to the second combustion zone, and a third amount of the third portion of the separated oxygen gas to be sent to the third combustion zone, the first amount, the second amount, and the third amount being determined based on a difference between: a total amount of oxygen specified for combustion of the fuel in the first, second, and third combustion zones, and an amount of oxygen determined to be within the first and second oxidant flows.