Distributor plate in a fluidized bed reactor
AssigneeA. Ahlstrom Corporation
InventorJuhani Isaksson
Life of this patent
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Abstract
The grid plate is disposed between the fluidized bed reactor chamber and an underlying wind box and includes a plurality of nozzles for feeding fluidizing gas from the wind box into the reaction chamber. The nozzles are configured to afford different pressure drops across the grid such that with increasing pressure, additional nozzles are actuated in response to increasing pressure differences across the plate whereby fluidized bed start-up and steady state operating conditions may be facilitated.
Claims22
In a fluidized bed reactor for combustion or gasification processes having a reactor chamber for particulate material, a wind box below the reactor chamber, and a grid plate for disposition between the reactor chamber and the wind box at an interface therebetween, the improvement comprising a plurality of nozzles distributed across and through said grid plate including in a central portion thereof for substantially evenly distributing across said grid plate fluidizing gas from the wind box into the reactor chamber, and means including first and second sets of said plurality of nozzles having respective particulate material retention means for enabling flow of fluidizing gas from said wind box through said nozzle sets into said reactor chamber at different initial pressure drops across said grid plate, respectively, during initial fluidization of said reactor whereby, upon said initial fluidization, gas flow through said first and second sets of nozzles commences sequentially in response to said different initial pressure drops, respectively.
In a fluidized bed reactor having a reactor chamber for particulate material, a wind box below the reactor chamber, and a grid plate for disposition between the reactor chamber and the wind box at an interface therebetween, the improvement comprising first and second sets of nozzles through said grid plate for feeding fluidizing gas from the wind box and substantially evenly distributing the gas into the reactor chamber after initial fluidization thereof, and means for providing different initial pressure drops across said first and second sets of nozzles in said grid plate during initial fluidization of said reactor including means carried by the nozzles of said first and second sets of nozzles for retaining different magnitudes of particulate material therein, respectively, whereby gas flow through said first and second sets of nozzles during initial fluidization of said reactor is initiated sequentially in response to pressure drops across said grid plate corresponding to said different pressure drops, respectively.
A fluidized bed reactor for combustion or gasification processes comprising:
- a fluidized bed reaction chamber for particulate material and operable at a predetermined fluidizing gas flow rate;
- a wind box disposed below said fluidized bed reaction chamber;
- a grid plate in said reactor disposed between said fluidized bed reaction chamber and said wind box at an interface therebetween;
- means carried by said grid plate including first and second sets of nozzles for feeding fluidizing gas from said wind box through said grid plate for substantial even distribution of the fluidizing gas across said grid plate into said fluidized bed chamber after start-up of the reactor;
- and
- particulate material initially disposed inside said first and second sets of nozzles;
- said first and second sets of nozzles having retention means for retaining different quantities of said particulate material inside said nozzles for providing different initial pressure drops across said grid plate, respectively, said second set of nozzles having an initial pressure drop such that fluidizing gas flows therethrough initially at a fluidizing gas flow rate corresponding to a percentage of the predetermined fluidizing gas flow rate in the reactor different than the percentage of the predetermined fluidizing gas flow rate in the reactor at which gas initially flows through said first set of nozzles.
A method of starting up a fluidized bed reactor having a reaction chamber, a wind box, a grid plate at an interface therebetween and a first and second sets of nozzles through the grid plate each for flowing fluidizing gas from the wind box and substantially evenly distributing the fluidizing gas across said grid plate and into the reaction chamber, comprising the steps of providing particulate bed material inside said first set of nozzles and establishing at least in part a first predetermined pressure drop across said first set of nozzles before fluidizing gas may flow therethrough, initiating flow of fluidizing gas from the wind box into said reaction chamber through the said first set of nozzles at said first predetermined pressure drop across the grid plate sufficient to blow the particulate bed material out of said first set of nozzles, providing particulate bed material inside said second set of nozzles, and establishing at least in part a second predetermined pressure drop across said second set of nozzles before gas may flow therethrough, and initiating the flow of fluidizing gas through said second set of said nozzles from the wind box into said reaction chamber at said second predetermined pressure drop across the grid plate higher than said first predetermined pressure drop and sufficient to blow the particulate bed material out of said second set of nozzles, whereby, at reactor start-up, fluidizing gas flows through said first set of nozzles before flowing through said second set of nozzles.
In a fluidized bed reactor having a reactor chamber containing particulate material, a wind box below the reactor chamber, and a grid plate for disposition between the reactor chamber and the wind box at an interface therebetween, the improvement comprising first and second sets of a plurality of nozzles in said grid plate each for feeding fluidizing gas from the wind box and substantially evenly distributing it in the reactor chamber, and means carried by said grid plate for enabling initiation of fluidizing gas flow through said first and second sets of nozzles during initial fluidization of said reactor at two different pressure drops across said grid plate, respectively, including means carried by said first and second sets of nozzles for retaining particulate material therein whereby fluidizing gas flow through said first and second set of nozzles during reactor start-up is initiated in response to pressure drops across said grid plate corresponding to said different pressure drops, respectively.
A method of starting up a fluidized bed reactor having a reaction chamber, a wind box, a grid plate at an interface therebetween, and first and second sets of a plurality of nozzles each through the grid plate for flowing fluidizing gas from the wind box to the reaction chamber, comprising the steps of initiating flow of fluidizing gas through said first and second sets of the plurality nozzles in sequences in proportion to increasing initial pressure drops across said grid plate.
Dependencies are inferred from the claim text.