Fluidized bed reactor and distribution system

Abstract

This invention provides a fluidized bed reactor with improved method and apparatus for inhibiting and clearing clogging of the fluid distribution network in such reactor. In particular, at least one channel or reservoir of fluid is provided over at least a selected portion of the distribution network, with fluid from such column/reserve being released to maintain flow and pressure in the distribution network as the media bed is defluidized. For the preferred embodiment, the fluid column is (a) a feed pipe connecting a fluid inlet which is above the reactor fluid level to the distribution network; and (b) a plurality of risers which, for the preferred embodiment, extend from the end of each lateral tube of the distribution network. A vacuum breaker is provided for each fluid column to permit fluid to flow from the column into the network when pressure is removed. A valve controlled opening may be provided at the top of each riser to permit purging of the distribution network through the openings when the valve is opened and to provide access to the distribution network for clearing clogs without requiring removal of the media bed.

What is claimed is: 
     
       1. A fluidized bed reactor for filtering fluids comprising: a reactor tank defining a volume;   a media bed disposed within said tank to a selected level;   a fluid inlet to said tank;   a distribution network .Iadd.within the media .Iaddend.connected to receive fluid from said inlet and having outlet ports for distribution of the fluid through the media bed;   a fluid outlet from said tank, said outlet maintaining a selected fluid level in the tank, which level is above that of the media; and   flow means for temporarily maintaining a gravity fed fluid flow through at least a portion of said distribution network after a termination in fluid flow from the fluid inlet.   
     
     
       2. A reactor as claimed in claim 1 wherein said flow means includes at least one riser, each riser extending substantially vertically from a selected portion of said network to a height above said selected fluid level and being connected to receive fluid from said network, fluid normally rising in said risers to a level above said selected fluid level when there is fluid flow to said network. 
     
     
       3. A reactor as claimed in claim 2 wherein said distribution network includes a plurality of spaced lateral tubes, each having a plurality of spaced ports, and wherein there is at least one riser extending from each of said lateral tubes. 
     
     
       4. A reactor as claimed in claim 3 wherein said network includes a main conduit connected to receive fluid from said fluid inlet, and a plurality of lateral tubes extending from opposite sides of said conduit for a selected length, and wherein the riser extending from each lateral tube extends from a point on the tube near the end of the selected length. 
     
     
       5. A reactor as claimed in claim 3 including an opening near the top end of each riser, and valve means for normally closing said openings, said valve means, when open, permitting purging of at least a portion of the network through the corresponding opening. 
     
     
       6. A reactor as claimed in claim 3 including a small orifice near the top end of each riser. 
     
     
       7. A reactor as claimed in claim 1 wherein said fluid inlet enters said tank at a level above said selected fluid level, and wherein said flow means includes a pipe connecting said fluid inlet to said distribution network, and vacuum breaker means operative after said termination of fluid flow for permitting fluid in said pipe to flow into said distribution network. 
     
     
       8. A reactor as claimed in claim .[.6.]. .Iadd.7 .Iaddend.wherein said flow means further includes at least one riser, each riser extending substantially vertically from a selected portion of said network to a height above said selected fluid level and being connected to receive fluid from said network, fluid normally rising in said risers to a level above said selected fluid level when there is fluid flow to said network. 
     
     
       9. A reactor as claimed in claim 1 wherein said flow means includes means for providing at least one column of fluid connected to and extending above said distribution network, the height of each of said fluid columns being greater than said selected fluid level in said reactor; and means for permitting each column of fluid to flow into the distribution network after said termination of fluid flow.   
     
     
       10. A method for inhibiting clogging of the fluid distribution network .Iadd.within the media bed .Iaddend.of a fluidized bed reactor comprising the steps of: providing at least one column of fluid connected to and extending above said distribution network, the height of each of said fluid columns being greater than the fluid level in said reactor; and   permitting each column of fluid to flow into the distribution network in the event there is a termination of normal fluid flow to said network.   
     
     
       11. A method as claimed in claim 10 including the step of providing a vacuum breaker for each column at least when said termination of normal fluid flow occurs. 
     
     
       12. A method as claimed in claim 11 wherein said method includes the step of purging the network of media which has entered the network from the fluidized bed. 
     
     
       13. A method as claimed in claim 12 wherein said providing step includes providing at least one riser extending from the network, which riser is normally sealed at its upper end, and said purging step includes the step of opening the sealed end of the riser, permitting a quantity of fluid from the riser and the network to gush out through the resulting opening. 
     
     
       14. In a fluidized bed reactor of a type having a tank containing a media bed to a selected level through which fluid is to be passed for filtering, and a fluid outlet which at least in part maintains a selected fluid level in the tank, which level is above the selected media level, the improvement comprising a distribution system comprising: a fluid inlet to said tank;   a distribution network .Iadd.within said media bed .Iaddend.connected to receive fluid from said inlet and having outlet ports for the distribution of the fluid through the media bed;   means for maintaining at least one fluid reserve, each of said reserves being positioned over a selected portion of said network at a level above said selected fluid level; and   means for permitting said reserves to flow into at least the corresponding selected portion of the network after a termination in fluid flow from said fluid inlet. .Iadd.   
     
     
       15.  A fluidized bed reactor for filtering fluids comprising: a reactor tank defining a volume;   a media bed disposed within said tank to a selected level;   a fluid inlet to said tank;   a distribution network within said media bed connected to receive fluid from said inlet and having outlet ports for distribution of the fluid through the media bed;   a fluid outlet from said tank, said outlet maintaining a selected fluid level in the tank, which level is above that of the media; and   risers passing through and extending to a selected height above said media bed from a plurality of points on said distribution network, said risers controlling media clogging of said distribution network. .Iaddend..Iadd.16. A reactor as claimed in claim 15 including a vacuum breaker for each riser for permitting air to escape when there is pressure in the distribution network so that fluid can rise in said risers and for permitting air to enter the riser so that fluid can flow from the riser into the distribution network when pressure drops in the distribution network. .Iaddend..Iadd.17. A reactor as claimed in claim 15 including an opening near the end of each riser, and a element for normally closing said openings, said element, when not closing the opening, permitting purging of at least a portion of the network through the corresponding   
     
     
        opening to flush media from the network. .Iaddend..Iadd.18.  A reactor as claimed in claim 15 including a normally closed access opening near the top of each riser, each of said openings, when open, permitting access to at least a portion of the distribution network to clear clogs therefrom. .Iaddend..Iadd.19. A reactor as claimed in claim 18 including at least one of a high pressure fluid source, a reamer and a brush which is passed through said opening and the corresponding riser to clear selected clogs. .Iaddend..Iadd.20. A fluidized bed reactor for filtering fluids comprising: a reactor tank defining a volume;   a media bed disposed within said tank to a selected level;   a fluid inlet to said tank;   a distribution network within said media bed connected to receive fluid from said inlet and having outlet ports for distribution of the fluid through the media bed;   a fluid outlet from said tank, said outlet maintaining a selected fluid level in the tank, which level is above that of the media; and   at least one riser connected to receive flow fluid from said distribution network, said riser extending substantially vertically from a selected portion of said distribution network through said media bed to a height which is at least above said selected level of the media bed.   
     
     
        .Iaddend..Iadd.21.  A fluidized bed reactor according to claim 20 comprising a plurality of said risers. .Iaddend..Iadd.22. A fluidized bed reactor according to claim 20, wherein said at least one riser extends above said selected fluid level, and further comprising at least one opening in each said at least one riser above the selected fluid level in said tank near the top of the riser. .Iaddend..Iadd.23. A fluidized bed reactor according to claim 22, wherein said at least one riser comprises a plurality of openings above the selected fluid level and at least one of said openings is a valve controlled opening near the top of said riser above the selected fluid level in said tank. .Iaddend.