Method and apparatus for operating a circulating fluidized bed system
AssigneeA. Ahlstrom Corporation
InventorTimo Hyppanen
Life of this patent
Estimating the term…
Abstract
In association with a circulating fluidized bed reactor, a bed of particles is established in the return duce for particles from the particle separator to the combustion chamber. Inlet openings extend from the bed of particles into the combustion chamber, and the height of the particle bed is maintained above the inlet openings a sufficient distance to form a gas seal. The particles in the bed are fludized, and also transporting nozzles are arranged at different levels for transporting the particles from the bed through the inlet openings into the combustion chamber. Heat exhangers (e.g. superheaters) may be provided in the bed to recover heat from the particles.
Claims32
A method of operating a circulating fluidized bed reactor system, utilizing a combustion chamber, having a fluidized bed of particles therein, a particle separator connected to a discharge opening in the upper part of the combustion chamber, a return duct connected in its upper part to the particle separator and in its lower part to the combustion chamber through two or more inlets disposed one on top of the other and including a top inlet, and a gas outlet in the particle separator, the method comprising the steps of:
- (a) establishing a fast fluidized bed of solid particles in the combustion chamber so that a particle suspension comprising flue gases and solid particles entrained therein is caused to flow upwardly in the combustion chamber,
- (b) collecting solid particles separated from the gas and particle suspension,
- (c) directing the collected solid particles into the return duct,
- (d) establishing a bed of solid particles in the return duct immediately in front of the inlets and having an upper surface above the top inlet to provide a gas seal to substantially prevent the passage of gas through the inlets, and
- (e) introducing transporting gas into the bed of solid particles in the return duct to effect recycling of particles from the bed through the inlets into the combustion chamber.
A circulating fluidized bed reactor system, comprising:
- a combustion chamber, having a fast fluidized bed of particles therein and a discharge opening in an upper part thereof,
- a particle separated connected to the discharge opening in the upper part of the combustion chamber,
- a return duct having an upper part connected to the particle separator and a lower part connected to the combustion chamber,
- a gas outlet in the particle separator,
- said return duct including means for collecting solid particles separated from a particle suspension flowing upwardly in the combustion chamber to establish a bed of solid particles in said return duct, the bed having an upper surface;
- inlet means, comprising at least two horizontal or inclined slot-like inlet openings disposed one on top of the other, and including a top inlet, connecting the lower part of said return duct with the combustion chamber, said top inlet being disposed in said return duct at a level below the level of the upper surface of the bed of solid particles so that the particles engage the return duct at the inlet and substantially prevent the passage of gas through the inlets, providing a gas seal;
- and
- transporting gas nozzles disposed in operative association with the lower part of the return duct, for transporting particles from the bed towards the inlet means for discharging particles from the return duct into said combustion chamber.
Method of operating a circulating fluidized bed reactor system, utilizing a combustion chamber, having a fluidized bed of particles therein, a particle separator connected to a discharge opening in the upper part of the combustion chamber, a return duct connected in its upper part to the particle separator and in its lower part to the combustion chamber through inlets, the inlets comprising two or more horizontal or inclined slot-like openings disposed one on top of the other and opening directly into the combustion chamber from the return duct, and a gas outlet in the particle separator, the method comprising the steps of:
- (a) establishing a fast fluidized bed of solid particles in the combustion chamber so that a particle suspension comprising flue gases and solid particles entrained therein is caused to flow upwardly in the combustion chamber,
- (b) collecting solid particles separated from the gas and particle suspension,
- (c) directing the collected solid particles into the return duct,
- (d) establishing a bed of solid particles in the return duct to provide a gas seal, and ensuring that the bed of particles is above all of the horizontal or inclined slot-like openings, and
- (e) introducing transporting gas into the return duct, for recycling particles from the bed through the horizontal or inclined slot-like openings into the combustion chamber, to introduce particles directly from the bed into the combustion chamber.
A circulating fluidized bed reactor system, comprising:
- a combustion chamber, having a fast fluidized bed of particles therein and a discharge opening in an upper part thereof,
- a particle separator connected to the discharge opening in the upper part of the combustion chamber,
- a return duct having an upper part connected to the particle separator and a lower part connected to the combustion chamber,
- a gas outlet in the particle separator,
- said return duct including means for collecting solid particles separated from a particle suspension flowing upwardly in the combustion chamber to establish a bed of solid particles in said return duct,
- inlet means, comprising at least two superimposed inlet openings, connecting the lower part of said return duct with the combustion chamber,
- transporting gas nozzles disposed in operative association with the lower part of the return duct, for transporting particles from the bed towards the inlet means for discharging particles from the return duct into said combustion chamber;
- and
- a second return duct, disposed adjacent a wall inside said combustion chamber, for collecting particles separated from the upwardly-flowing gas and particle suspension and flowing downwardly along the wall.
A method of operating a circulating fluidized bed reactor system, utilizing a combustion chamber, having a fluidized bed of particles therein, a particle separator connected to a discharge opening in the upper part of the combustion chamber, a return duct connected in its upper part to the particle separator and in its lower part to the combustion chamber through inlets, and a gas outlet in the particle separator, the method comprising the steps of:
- (a) establishing a fast fluidized bed of solid particles in the combustion chamber so that a particle suspension comprising flue gases and solid particles entrained therein is caused to flow upwardly in the combustion chamber,
- (b) collecting solid particles separated from the gas and particle suspension,
- (c) directing the collected solid particles into the return duct,
- (d) establishing a bed of solid particles in the return duct having the level of its upper surface above the level of the inlets, to provide a gas seal, and
- (e) introducing transporting gas with a velocity of <0.5 m/s into the bed of solid particles in the return duct to effect recycling particles from the bed through the inlets into the combustion chamber, and to establish a slowly bubbling fluidized bed at least in a part of the return duct.
Dependencies are inferred from the claim text.