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US 4,062,656 AGranted
Fluidized bed apparatus
AssigneeExxon Research & Engineering Co.
InventorsDon E. Blaser, Arthur C. Worley
Life of this patent
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AssigneeExxon Research & Engineering Co.
InventorsDon E. Blaser, Arthur C. Worley
Estimating the term…
A fluidized bed apparatus having an outer vessel provided at a lower region with a plenum chamber as well as a grid situated directly above the plenum chamber and carrying a plurality of nozzles through which gas flows from the plenum chamber into the space in the vessel above the grid. These nozzles provide a given pressure drop in the gas flowing therethrough while as the gas flows from the plenum chamber through each nozzle there is also provided by way of a suitable structure a preliminary pressure drop, so that a two-stage pressure drop is provided in the gas flowing through each nozzle from the plenum chamber into the vessel above the grid. In this way it is possible to achieve a flow of gas above the grid sufficient to maintain the particles suspended in the fluidized bed while attrition of the particles is maintained at a minimum so that very little if any fines flow out of the vessel with gas which is formed therein. According to this method, the particles are petroleum coke particles while the gas is a mixture of steam and air maintained in the plenum chamber at a pressure of only 1-5 psig above the pressure in the bed while at the region of the interior of the vessel above the grid the temperature is on the order of 1500.degree.-1800.degree. F. The grid supporting the nozzles is sloped 3.degree. to 5.degree. downwards towards a center well and supporting member to allow solid agglomerations such as lumps of coke and slag to move radially inward into the well for withdrawal.
In a fluidized bed apparatus, such as a petroleum coke gasifier, an outer vessel having at a lower region thereof a plenum chamber and carrying at said lower region above said plenum chamber a grid which extends across said vessel, and said grid carrying a plurality of nozzle means distributed over said grid and communicating through said grid with said plenum chamber for receiving gas therefrom and distributing the gas into the space in said vessel over said grid for maintaining particles in a fluidized condition above said grid, each of said plurality of nozzle means providing a drop in the pressure of gas received from said plenum chamber as the gas flows out of said nozzle means into the space in the vessel above said grid, first orifice means situated adjacent said grid in the path of gas flow to each of said nozzle means to provide a preliminary drop in the pressure of the gas flowing from said plenum chamber to each nozzle means, and second orifice means at the outlet of said nozzle means to provide a secondary drop in the pressure of the gas flowing from said plenum chamber into the space above the grid, so that the total pressure drop between said plenum chamber and the space over said grid occurs in two distinct stages within said nozzle means.
An improved nozzle means adapted for mounting upon the supporting grid of a fluidized bed said nozzle means comprising a central elongated metal conduit of relatively large bore to cause minimal pressure drop upon gas flowing therethrough and adapted to be secured at a lower end thereof to said grid in a generally perpendicular relationship to the plane of said grid, first orifice means at said lower end of said conduit and disposed in the plane of said grid for establishing a first stage pressure drop upon a gas flowing from below said grid through said elongated conduit, and at least one second orifice means located at the opposite end of said conduit for establishing a second stage pressure drop upon a gas flowing from said conduit into the area of the fluidized bed above said grid whereby, even though the upper portion of said conduit may fail or fracture due to exposure to the environment of the fluidized bed, the first stage orifice means will remain operative at the lower end of said conduit.
Dependencies are inferred from the claim text.