Use of pre-oxidized ilmenite in fluidized bed boilers
AssigneeImprobed AB
InventorsBengt-Ake Andersson, Fredrik Lind, Henrik Thunman
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Abstract
The invention relates to a method for starting up a fluidized bed boiler, such as a circulating fluidized bed (CFB) or a bubbling fluidized bed (BFB) boiler, for operation with a predetermined concentration of ilmenite particles in the bed material. The invention also relates to a method for pre-oxidizing ilmenite, to pre-oxidized ilmenite and to the use of pre-oxidized ilmenite in a fluidized bed boiler.
Claims17
A method for starting up a fluidized bed boiler for operation with a bed material that comprises a predetermined concentration of ilmenite particles, the ilmenite particles comprising at least one rock ilmenite and sand ilmenite, the method comprising:
- i) providing a bed material to the fluidized bed boiler;
- and
- ii) heating the bed material,
- wherein pre-oxidized ilmenite particles are provided to the bed material in the fluidized bed boiler before a predetermined operating temperature in the bed is reached.
A method for using pre-oxidized ilmenite particles to reach a predetermined concentration of ilmenite particles in a bed material for operating a fluidized bed boiler, wherein:
- i) pre-oxidized ilmenite particles are produced inside a furnace in a process comprising the steps of:
- a) heating the furnace to a predetermined temperature;
- b) maintaining an oxidizing environment inside the furnace;
- c) feeding fresh ilmenite particles to the furnace;
- d) pre-oxidizing the ilmenite particles by subjecting the ilmenite particles to the oxidizing environment inside the furnace at the predetermined temperature;
- e) removing pre-oxidized ilmenite particles from the furnace;
- wherein pre-oxidized ilmenite particles removed from the furnace are provided to the fluidized bed boiler to reach a predetermined concentration of ilmenite particles in the bed material before a predetermined operating temperature in the bed is reached;
- and/or
- ii) fresh ilmenite particles are provided to the fluidized bed boiler and are heated to a temperature wherein the ilmenite particles are pre-oxidized, and wherein the pre-oxidized ilmenite particles are used to reach a predetermined concentration of ilmenite particles in the bed material before a predetermined operating temperature in the bed is reached.
Dependencies are inferred from the claim text.