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AssigneeThe United States of America as represented by the United States Department of Energy
InventorsJoseph S. Mei, James DeVault, John S. Halow
Estimating the term…
A gas cleaning filter is formed in-situ within a vessel containing a fluidizable bed of granular material of a relatively large size fraction. A filter membrane provided by a porous metal or ceramic body or such a body supported a perforated screen on one side thereof is coated in-situ with a layer of the granular material from the fluidized bed by serially passing a bed-fluidizing gas stream through the bed of granular material and the membrane. The layer of granular material provides the filtering medium for the combined membrane-granular layer filter. The filter is not blinded by the granular material and provides for the removal of virtually all of the particulates from a process gas stream. The granular material can be at least partially provided by a material capable of chemically reacting with and removing sulfur compounds from the process gas stream. Low level radioactive waste containing organic material may be incinerated in a fluidized bed in communication with the described filter for removing particulates from the gaseous combustion products.
A filter in combination with a fluidized bed comprising a vessel having a chamber therein for containing a bed of granular material, inlet means underlying the bed of granular material for introducing at least one stream of gas into the chamber for fluidizing the bed of granular material, outlet means overlying the bed of granular material for the discharge of said at least one stream of gas from the chamber after passing through the fluidized bed of granular material, and filter means within said chamber adapted to be contacted by a particulate laden gas stream for removing particulate material borne by the gas stream contacting the filter means prior to the discharge of the gas stream from the chamber, said filter means comprising a ceramic or metal membrane characterized by having throughgoing pores of size larger than at least a minor portion of the granular material and the particulate material borne by the said gas stream and a layer of granular material from said bed on surface regions of the membrane exposed to the particulate laden gas stream, said layer of granular material being supported on said surface regions of the membrane by said gas stream and having a sufficient porosity for the passage of said gas stream therethrough while filtering therefrom virtually all of the granular material and the particulate material borne thereby including essentially all of said minor portion of the granular material prior to the passage of the gas stream through the pores in the membrane and the discharge thereof from said chamber through said outlet means.
A method for forming in situ a filter for filtering particulate material from a particulate laden gas stream, comprising the steps of exposing a surface region of a relatively porous ceramic or metal membrane to a bed of fluidizable granular material, passing a stream of gas through the bed of granular material for fluidizing the bed and entraining granular material therefrom and contacting the exposed surface region of the membrane with the gas stream laden with granular material from said bed for removing all but a minor portion of the granular material from the gas stream as it passes through the membrane to effect and maintain the deposit of granular material removed from the gas stream on the surface region of the membrane, contacting the surface region of the membrane for a sufficient duration to form in situ a layer of granular material on the surface region of the membrane with said layer being of a porosity substantially less than that of the membrane so as to form in combination with the membrane a particulate filter capable of removing virtually all particulate material and granular material from said bed borne by a particulate-laden bed-fluidizing gas stream as it flows from said bed of granular material through said filter and contacts and passes through the filter.
Dependencies are inferred from the claim text.